Dose Constraints, Treatment Schemes, Treatment Machine/Procedures Designs and QA

What are typical dose-volume constraints clinically acceptable for the Iliac Crests?

***CCCN: V50Gy <= 10%*** V30Gy <= 50% volume (RTOG 0529) (Anus Treatments - Geisinger) V40Gy <= 35% volume (RTOG 0529) (Anus Treatments - Geisinger) V50Gy <= 5% volume (RTOG 0529) (Anus Treatments - Geisinger)

According to ABRPhysicsHelp summary of TG-63, approximately how many patients encountered ina clinic will have at least one prosthesis?

1%-4%

According to ABRPhysicsHelp and AAPM TG-256, what two things must be done to make the proton beam Bragg peak useful to a clinical capacity?

1. Bragg peak must be shift to desired depth. 2. Bragg peak needs to be a Spread Out Bragg Peak (SOBP) to cover desired target.

According to ABRPhysicsHelp, what is the purpose of TG-59?

(1) Examine current HDR treatment practices. (2) Detail MINIMUM HDR procedures involved in staffing, training, treatment QA, and emergency procedures.

According to ABRPhysicsHelp, what are 6 key characteristics of a Cyclotron?

(1) Fixed Energy (2) Need degrader/energy selection system (3) Continuous Beam Current (4) Higher max beam current compared to Synchrotrons (5) Smaller footprint (especially superconducting Cyclotron) compared to Synchrotrons (6) Designed for single ion type therapy (so have choose between protons, carbon ion, etc.)

According to Wepassed!, what are some of the methods employed by MLC control systems to verify proper leaf positioning? List them and briefly elaborate upon each within a couple sentences as necessary.

(1) Motor Encoder --- motion of each leaf is tracked by individual encoders. (2) Resistance Band --- may be in the form of a "contact ball" attached to each leaf, which generates a variable resistance signal based upon the ball's position. (3) Optical beam --- usually only employed during initialization of MLC leaves. During the initialization exercise, the MLCs motors drive the leaves to a specific set of positions according to light beams directed to receptors within the MLC structure.

According to ABRPhysicsHelp, What are adult malignancies often treated using proton therapy?

(1) Uveal Melanoma (2) Paraspinal tumors (3) Prostate cancer

What are typical dose-volume constraints clinically acceptable for the Great Vessels?

*** SRS: D10cc < 31Gy*** *** SBRT: D10cc < 47 Gy *** Dmax < 37 Gy (1 frac SBRS - TG-101 - aneurysm) D10cc < 31 Gy (1 frac SBRS - TG-101 - aneurysm) Dmax < 45 Gy (3 frac SBRS - TG-101 - aneurysm) D10cc < 39 Gy (3 frac SBRS - TG-101 - aneurysm) Dmax < 53 Gy (5 frac SBRS - TG-101 - aneurysm) D10cc < 47 Gy (5 frac SBRS - TG-101 - aneurysm)

According to ABRPhysicsHelp and TG-179, what is the typical scan time of a kV-CBCT?

1-2 minutes

According to ABRPhysicsHelp, what is greatest x-ray energy that can be generated by a Van De Graaff Generator used radiation therapy?

10 MV

What is a typical SRS/SRT treatment prescription for Acoustic Neuromas (Vestibular Schwannomas)?

12 Gy in 1 fx -> if no hearing preservation concern 21 Gy in 3 fxs -> if hearing preservation concern

According to ABRPhysicsHelp and Google what is the energy of kilovoltage machines used for "Contact" therapy? What is "Contact" therapy exactly?

40-50 kVp Its really a historical name for brachytherapy using electronic x-rays. It is also know as Papillon radiotherapy due to the "papillon technique" for treating rectal cancer.

According to ABRPhysicsHelp and TG-56 and your own experience, what are recommended QA tests for HDR afterloaders on a daily basis? What are the tolerances for each?

- Door interlock, warning lights, alarms, console buttons, switches, emergency interlocks -> Functional - Visual inspection of source transfer tubes -> kink free and attach properly. - Positional accuracy of source -> 1 mm - Timer check against standard -> +-2% (but I am more comfortable with 1%)

According to ABRPhysicsHelp and TG-56 and your own experience, what are recommended QA tests for HDR afterloaders on an annual basis? What are the tolerances for each? Elaborate each

- Emergency Retraction -> Functional: make sure manual crank for retracting source is function. - Emergency Procedures Training -> Make sure authorized users and licensed users receive training on how to handle stuck sources. Training usually provided by vendor on annual basis. - Applicator integrity and Source loading integrity (visually or by x-ray) IF APPLICABLE -> functional

According to ABRPhysicsHelp and TG-59, what are the three type of emergencies that could occur during an HDR brachytherapy treatment? List them and elaborate upon what kind of events each entail and precautions/response measures that should be in place when such emergencies occur.

(1) Physical Plant Emergencies --- include fire, physical disasters (storms, tornados, floods, earthquakes, etc.), and transient power interruptions. RESPONSE: (a) If necessary, should have system in place that warns emergency responders that radioactive source present. (b) There should be some sort of backup power system equipped with the unit so that the source will retract and maintain a record of partial treatment. (2) Minor emergencies --- abnormal performance of device that prevents or interrupts treatment, such as loose or kinked catheters, vault door not properly closing, etc. RESPONSE: - depends on the error/warnings the consoles give and own assessment of likely causes. (3) Major emergencies --- Really anything that requires the operators, physicist, and radiation oncologist to intervene to retract source into safe. (total computer failure, source retraction failure, patient medical emergency, etc.) RESPONSE: (a) See if can resolve issue without manual retraction via emergency stops in console area. (b) If need to manually retract it . . . - enter room with GM meter. - Hit any emergency retract buttons on the way into the vault. - Retract source into unit via hand crank. - Survey patient and afterloader. - If still detecting source, need to remove applicator and place into pig, which the radiation oncologist should do. - Survey patient, afterloader, and pig. - Remove patient from vault and survey patient and staff who had entered the room.

According to Wepassed! and ABRPhysicsHelp, what type of tests are typically done during the acceptance of a conventional linac? List in the order you would do them, and elaborate on the type of test within a sentence as necessary.

(1) Radiation Survey and Head Leakage Check -> will need pressured ion chamber, film, and possibly rem ball. (2a) Mechanical Safety Test - Collision Interlocks work, door interlocks, emergency shutdown, warning lights, etc. (2b) Mechanical/Radiation Isocenter - WL test. or very least startshots (2c) ODI, Rad-to-light, and laser alignment. (2d) Gantry/Collimator/Table/Jaw/MLC accuracy. (3) Dosimetry checks - Rough Absolute Calibration Check, MU/Dose Rate Stability checks. Relative dose factors (FS, wedges, etc.), and quick energy checks.

According to ABRPhysicsHelp and TG-147, what are the nonradiographic localization and position systems common to radiotherapy applications? List them

(1) Radiofrequency systems (2) Infrared (3) Laser (4) Video

According to ABRPhysicsHelp and AAPM Online Learning Center Lecture, The concepts of machine QA for photon therapy accelerator systems and proton therapy accelerator systems are mostly the same. However, there are some differences. What are the Daily QA checks that are unique to proton therapy accelerator systems? What equipment is normally utilized to do these measurements?

(1) Range Check (2) Beam Spot Position A Daily QA array with variations of beam build-up across the surface of device.

According to ABRPhysicsHelp and TG-147, what are few clinical applications of dual camera optical tracking systems?

(1) Real-time motion monitoring during treatment. (2) Guided patient position corrections when setting up patient for each treatment. (3) Beam gating during treatment - can halt beam if certain degree of motion.

According to ABRPhysicsHelp and TG-147, what are few clinical applications of radiofrequency localization and positioning systems?

(1) Real-time motion monitoring during treatment. (2) Guided patient position corrections when setting up patient for each treatment. (3) Respiratory motion management . . . MAYBE

According to ABRPhysicsHelp, power supplied to kilvoltage x-ray tubes via transformers has to be (1) ___________ to generate a (2) _________ _____________. Fill-in the blanks. In one sentence, elaborated upon entry of (1)? What are the two reasons why implementing entry (1) is important for kilovoltage x-ray tubes to operate?

(1) Rectified (2) constant voltage Rectification uses diodes to modulate an electric potential with time varying characteristics of an alternating current power source into an electric potential with time stagnant characteristics of a direct current power source. (1) Prevents electrons from flowing backward toward the cathode and potentially damaging it. (2) Enables efficient use of AC power sources - the whole wave cycle of the AC power can be utilized.

According to ABRPhysicsHelp, What are the two possible issues regarding energy efficiency and safety for the Waveguide Transportation System of a C-arm Linac? How are the transport systems engineered to address these two issues?

(1) Reflection of microwave energy from the Klystron: address via the Circulator and impedance matching of joined waveguide transport systems. (2) Electrical arching of gases that may be present in the transport system - waveguide system filled with sulfur hexafluoride (SF_6) gas, which functions as a dielectric that allows the transmission of high power electric fields.

According to ABRPhysicsHelp and TG-147, In general, what are three key limitations of dual camera infrared tracking systems?

(1) Require direct line of sight between Ir reflector and camera. (2) IR cameras are susceptible to thermal drift: perceived signals change more drastically with time during the warm-up phase of a camera. (3) Only handles external motion IF not used concurrently with another system.

According to Krauss, what is the motivations/advantages for administering HDR prostate treatments, especially in relation to LDR treatments? List and elaborate upon each within a sentence as necessary.

(1) Shorter treatment time. (2) Patient not radioactive after administering treatment (as is the case for LDR treatments). (3) Decreased exposure to staff and general public. (4) Increased control over dosage administered. (5) The perceived increase in prostate cancer sensitivity to higher dose rates.

According to ABRPhysicsHelp, what are the two main sources of the large penumbra exhibited by Co-60 units, that is "large" relative modern day linacs?

(1) Simple, non-divergent primary and secondary collimation. (perhaps due to isotropic emission of Co-60) -> HENCE LARGE TRANSMISSION PENUMBRA (2) Source spot size (size of source) is large -> HENCE LARGE GEOMETRIC PENUMBRA

According to ABRPhysicsHelp and TG-179, what is are a couple of advantages of a MV-CBCT over a kV-CBCT?

(1) Simpler to maintain - no kV source and orthogonal arms to correlate with radiation isocenter. (2) Produce less artifact for high Z materials, such as prosthetics.

In a single sentence, describe the operation principle of a Van De Graaff Generator?

A machine that uses a belt to strip electrons from a donor source and carry them to spherical dome where the electrons are removed to create a high voltage differential.

According to ABRPhysicsHelp and TG-56, What are QA recommendations applicable to a Cs-137 LDR program? List the tests, applicable tolerances, and testing frequency for each. Elaborate upon each one within a sentence as necessary.

(1) Source Inventory and Ambient Exposure Rate Readings - Quarterly: NRC 10 CFR 35 requires this and exposure rate reading of source storage area. (2) Leak Testing - biannually - NRC 10 CRF 35 requires this at the testing frequency but TG-56 advises to do it also as physicist deems appropriate. (3) Loading/Unloading Applicators - Initially/Annually: Whenever a new applicator or source is acquired and annually. Test encompasses dosimetric evaluation of applicator/source, verification of applicator/source integrity, proper seed/ribbon spacing/positioning inside applicator, and applicator/source dimensions. (4) Source Calibration - Initially/Annually: usually a well chamber reading with an NIST traceable calibration factor, temperature/pressure correctinos, and constancy check of chamber to verify activity or air-KERMA strength. (5) Radiation Safety Surveys - as needed: Readings to be performed during all parts of the treatment to ensure compliance with radiation protection regulations.

According to ABRPhysicsHelp summary of TG-106, what are the aims of the TG-106 report?

(1) Standardize acceptance testing (2) Describe specific measurement setups (3) Describe potential sources of error (4) Recommend procedures for acquiring linear accelerator beam parameters

According to ABRPhysicsHelp and TG-147, other than reference point correlation, what are aspects of a nonradiographic localization and positioning system should be periodically QA and assessed during acceptance/commissioning? List each aspect, and briefly (single sentence) elaborate the QA/commissioning of that aspect.. Also mention the recommended frequency of QA for each system aspect.

(1) System Drift (Thermal Drift) - characterize position with time during warm-up phase, and QA that characterization periodically; annually (2) Reproducibility - document ability for system to yield same localization and/or positioning result throughout a number of sessions; annually and after equipment changes. (3) Tracking Accuracy - document ability for system to relay proper gating signals; monthly and annually (4) Localization Accuracy - document ability of system to relay proper positioning information; daily, monthly, and annually. (5) Response time (latency) - document ability of system to relay proper positioning information and gating signals at a reasonable frequency; annually

According to ABRPhysicsHelp and TG-147, what basic test should be done on an annual basis?

(1) Test emergency off switches (2) Test backup power supplies (3) Check camera mounting (4) System drift measurements (5) End-to-End Tests

According to ABRPhysicsHelp summary of TG-63, what are the three primary physical-interaction effects of having a hip prothesis in a radiation field relative to homogenous medium? List each of them and elaborate their impact on dosimetry within a couple of sentences for each effect. Which two of these three prothesis effects tend to negate each other, and under what circumstances? Answer within a couple of sentences.

(1) Tissue Interface effects - sharp increase in PDD of about 50% (for all energies) on beam entering-side while at the beam-exit side, a 5% decrease in PDD for energies < 10 MV but a 50% increase in PDD for energies > 10 MV due to pair production increases. (2) Attenuation effects - attenuation rate (attenuation per cm depth) of photon beams increases due to higher density. (3) Scatter effects - scatter increases due to increased density of implant. Attenuation and Scatter effects tend to negate each other for "large" fields.

According to ABRPhysicsHelp summary of TG-63, what are the typical construction materials of hip prostheses seen in patients today? What is the approximate density for each? List in ascending order of greatest frequency to lowest frequency.

(1) Titanium - 4.3 g/cm^3 - most commonly seen. (2) CoCrMo = a copper/chromium/molybdenum alloy - 7.9 g/cm^2 - probably a second most frequent or just as frequent. (3) stainless steel - 8.1 g/cm^3 - older implants may utilize these materials.

According to ABRPhysicsHelp, what are the different methods available for administering Craniospinal irradiation to patients? List them and briefly elaborate on the method within a few sentences.

(1) Tomotherapy -> administer treatment in continuous helical delivery. (2) Linac-Based --> could be prone but I have seen it or heard people prefer supine. Utilizes a pair of lateral opposing fields for brain and upper cervical spine and 2 (if adult) or single (if pediatric) PA field(s) to treat spinal column. If 2 fields, the junction of the fields is matched at the anterior of the cord. Cranial and Spinal field junctions are moved every few fractions to distribute hot and cold spots.

According to ABRPhysicsHelp, what are the typical factors contribution to variations in dose prescriptions for SRS/SBRT treatments? List them and elaborate within a sentence as necessary.

(1) Tumor type -> may necessitate increase in overall prescription dose. (2) Proximity of normal structures -> may require fractionation or increase in already desired fractionation. (3) Prior Radiotherapy - may necessitate lowering overall prescription dose. (4) Tumor Size -> Larger tumors get smaller doses

According to ABRPhysicsHelp, What are key characteristics of a "Single-Field Uniform Dose" plan in the context of proton therapy?

(1) Utilizes multiple fields (2) Each field optimized to approximate homogenous dose (3) "Forward Planning"

According to ABRPhysicsHelp, what are 7 key characteristics of a Synchrotron?

(1) Variable (discrete) energies (2) No need for additional degrader/energy selection system (3) Non-continuous: spill structure. "pulsed" beam on order of 100 ms to 1s (4) Lower max beam current compared to Cyclotron (5) Larger footprint compared to Cyclotron (6) Can (in principle) accelerate multiple other ions with one machine (can choose between protons, carbon ions, etc. for on accelerator)

According to ABRPhysicsHelp and TG-59, what aspects of an HDR treatment plan should be reviewed prior to initial delivery, during a 2nd check of treatment plan? List them out, and clarify any briefly as necessary.

(1) Verify Patient name and treatment date (2) Verify decay source strength (3) Verify correct system files for treatment delivery exported to the treatment unit. (4) Verify magnification factors of any DRRs or film that will be used to compare to any image verifications that would be performed during treatment administration. (5) Verify intended step size of dwell positions agrees with expected standard. (6) Verify prescription criteria are consistent with clinical intent --- applicators, implant geometry, # of fractions, total dose, isodose shape etc. appropriate for clinical indication and physician expectations.

According to ABRPhysicsHelp and TG-59, what are key structural aspects and/or methodology to a well-run HDR brachytherapy program? List them and elaborate upon each as necessary.

(1) Written Documentation (2) Developing a formal procedure. (3) Exploiting redundancy (4) Exploitation of quality improvement techniques.

According to ABRPhysicsHelp and TG-59, what are the suggested types of "documentation" that should be incorporated into a patient treatment course via an HDR program. List each and elaborate upon each within a couple sentences as necessary.

(1) Written directive --- a document or multiple documents that . . . (a) unambiguously identifies a patient. (b) includes a prescription (fraction size, number of fractions, total dose, treatment planning criteria). (c) describes applicators used. (d) accommodates appending of daily treatment records. (2) Treatment Plan Documentation --- a document or multiple documents that . . . (a) clearly identifies catheters (b) clearly identifies dwell positions, insertion lengths, spacing between dwell positions. (c) displays isodose plots (d) Details 2nd check calculations (e) features a some sort of QA check-off list for plan review and during treatment delivery. (f) features any post-treatment reports.

According to ABRPhysicsHelp, a Synchrocyclotron is most similar in design to the design of a (1) _____________ except that the frequency of the (2) _______ _________ is varied across the gap between the two (3)____________ with the intention of accounting for (4) __________ __________. Another consequence is that it produces a (5)_________ _______, unlike a (1) ____________. Fill in the blanks

(1) cyclotron; (2) electric field; (3) "dees" (electrodes); (4) relativistic effects; (6) pulsed beam.

How would one match the divergence of the the two cranial fields for a cranial-spinal treatment?

(1) half beam block so no divergence. (2) kick couch to amount proportional to cranial field size -> couch kick = arctan(cranial field size along cranial-caudal direction divided by 2/SAD of cranial field_

According to TG-50 (AAPM Report 72), What were the prime motivations for replacing conventional blocking with MLCs driven blocking?

(1) improved workflow efficiency and financial efficacy. (2) Improved safety

According to ABRPhysicsHelp, what are the 4 IGRT systems discussed in TG-179?

(1) kV CBCT (2) MV CBCT (3) MVCT (4) kVCT-on-rails

According to ABRPhysicsHelp, what are the two biggest limitations of Betratrons in the use of radiotherapy?

(1) limited field size (2) limited beam current

According to ABRPhysicsHelp, what are various diseases that may be treated with total body photon irradiation? What about non-disease applications?

(1) multiple myelomas (2) Limited Immunity Deficiencies (3) Limited Genetic Disorders (e.g. Diamond Blackfan Anemia) (4) Bone Palliation ***(5) Leukemia ***Immune system suppression - for skin grafts or bone marrow transplants.

According to ABRPhysicsHelp and TG-147, what are the two key advantages of nonradiographic localization and positioning systems in comparison to radiographic techniques?

(1) no ionizing radiation dose contributions. (2) Real-time feedback

According to ABRPhysicsHelp and TG-147, what are two key disadvantages of nonradiographic localization and positioning systems?

(1) system feedback can be "blocked" or "interfered" (2) often employ a surrogate (body markers, beacons, etc.)

What are typical dose-volume constraints clinically acceptable for the Optic nerve/chiasm? What are the toxicity endpoints?

*** Conventional Treatment: Dmax < 54 Gy *** *** SRS: Dmax < 10 Gy*** *** SBRT: Dmax < 25 Gy*** ***Endpoint: neuropathy*** Dmax < 55Gy (Brain Treatments - Geisinger) D0.2cc < 8Gy (SRS - Geisinger) Dmax < 10 Gy (SRS - Geisinger) Dmax < 54 Gy (Pharynx Treatments - RTOG 0225) V60Gy < 1% vol (Pharynx Treatments - RTOG 0225) Dmax < 10 Gy ( SRS - TG-101 - neuritis) D0.2cc < 8 Gy ( SRS - TG-101 - neuritis) Dmax < 17.4 Gy ( 3 frac SRT - TG-101 - neuritis) D0.2cc < 15.3 Gy (3 frac SRT - TG-101 - neuritis) Dmax < 25 Gy ( 5 frac SRT - TG-101 - neuritis) D0.2cc < 23 Gy (5 frac SRT - TG-101 - neuritis) QUANTEC Analysis 3D-CRT: Dmax < 55 Gy (<3% complication rate) SRS (Single Fraction): Dmax <12 Gy (<10% complication rate)

What are typical dose-volume constraints clinically acceptable for the Brachial Plexus?

*** Conventional Treatment: Dmax < 66 Gy *** *** SRS: D3cc < 14 Gy*** *** SBRT: D3cc < 27 Gy *** Dmax <= 6Gy (Breast Treatments - Geisinger) Dmax <= 66Gy (Lung Treatments - Geisinger) Dmax < 66 Gy (Spine Metastasis Treatments - RTOG 0631) V60Gy < 5 % vol (Spine Metastasis Treatments - RTOG 0631) Dmax < 17.5 Gy (1 frac SBRS - TG-101 - neuropathy) D3cc < 14 Gy (1 frac SBRS - TG-101 - neuropathy) Dmax < 24 Gy (3 frac SBRT - TG-101 - neuropathy) D3cc < 20.4 Gy (3 frac SBRT - TG-101 - neuropathy) Dmax < 30.5 Gy (5 frac SBRT - TG-101 - neuropathy) D3cc < 27 Gy (5 frac SBRT - TG-101 - neuropathy)

What are typical dose-volume constraints clinically acceptable for the Heart? What are the toxicity endpoints?

*** Conventional Treatment: Dmax < 70 Gy, V40Gy < 40% , V25Gy < 10%** *** SRS: Dmax < 22 Gy*** *** SBRT: Dmax < 38 Gy*** ***Endpoint: Pericarditis (inflammation of the pericardium)*** V30Gy <= 50% volume (Breast Treatments - Geisinger) V45Gy <= 35% volume (Breast Treatments - Geisinger) Dmax <= 70 Gy (Breast Treatments - Geisinger) V30Gy <= 50% volume (Lung Treatments - Geisinger) V45Gy <= 35% volume (Lung Treatments - Geisinger) Dmax <= 70 Gy (Lung Treatments - Geisinger) V40Gy < 100% vol (Lung Treatments - RTOG 0623) V45Gy < 67 % vol (Lung Treatments - RTOG 0623) V60Gy < 33% vol (Lung Treatments - RTOG 0623) Dmax < 22 Gy (1 frac SBRS - TG-101 - pericarditis) D15cc < 16 Gy (1 frac SBRS - TG-101 - pericarditis) Dmax < 30 Gy (3 frac SBRT - TG-101 - pericarditis) D15cc < 24 Gy (3 frac SBRT - TG-101 - pericarditis) Dmax < 30 Gy (3 frac SBRT - TG-101 - pericarditis) D15cc < 24 Gy (3 frac SBRT - TG-101 - pericarditis) Dmax < 38 Gy (5 frac SBRT - TG-101 - pericarditis) D15cc < 32 Gy (5 frac SBRT - TG-101 - pericarditis) QUANTEC Analysis 3D-CRT: V25 < 10% (<1% complication rate)

What are typical dose-volume constraints clinically acceptable for the Total Lungs? What are the toxicity endpoints?

*** Conventional Treatment: Dmean < 20 Gy, V20Gy < 35% *** *** SRS: D(at least 1000cc) < 7.5 Gy*** *** SBRT: D(at least 1000cc) < 13.5 Gy*** ***Endpoint: pneumonitis (inflammation of lung)*** Dmean <= 20Gy (any treatment - Geisinger) V5Gy <= 70% volume (any treatment - Geisinger) V20Gy <= 35% volume (any treatment - Geisinger) Dmean < 20 Gy (Lung Cancer Treatments - RTOG 0623 ) V20Gy < 37% vol (Lung Cancer Treatments - RTOG 0623 ) D(at least 1000cc) < 7.4 Gy (1 frac SBRS - TG-101 - pneumonitis) D(at least 1500cc) < 7 Gy (1 frac SBRS - TG-101 - basic lung function) D(at least 1000cc) < 12.4 Gy (3 frac SBRT - TG-101 - pneumonitis) D(at least 1500cc) < 11.8 Gy (3 frac SBRT - TG-101 - basic lung function) D(at least 1000cc) <13.5 Gy (5 frac SBRT - TG-101 - pneumonitis) D(at least 1500cc) < 12.5 Gy (5 frac SBRT - TG-101 - basic lung function) QUANTEC Analysis 3D-CRT: V20 < 30% (<20 % complication rate)

What are typical dose-volume constraints clinically acceptable for the Cochlea? What are the toxicity endpoints?

*** Conventional Treatment: Dmean < 45 Gy *** *** SRS: Dmax < 9 Gy*** ***SBRT: Dmax < 25 Gy*** ***Endpoint: sensory hearing loss*** Dmean <= 45Gy (Brain Treatments - Geisinger) Dmean <= 45 Gy (Oral Cavity Treatments - Geisinger) Dmean <= 45 Gy (Head & Neck Treatments - Geisinger) Dmax < 9 Gy (SRS - Geisinger) If treating tumor in ear, Prescription Dose <= 12-14 Gy ( SRS- Geisinger) Dmean <= 3.7 -4.2 Gy (SRS - Geisinger) V55 Gy < 5 % vol (Pharynx Treatment - RTOG 0615) Dmax < 9 Gy (SRS - TG-101 - hearing loss) Dmax < 17.1 Gy ( 3 frac SRT - TG-101 - hearing loss) Dmax <25 Gy ( 5 frac SRT - TG-101 - hearing loss) QUANTEC Analysis 3D-CRT: Dmean < 45 Gy (<30% complication rate) SRS (Single Fraction): prescription dose <14 Gy (<25% complication rate)

What are typical dose-volume constraints clinically acceptable for the Rectum? What are the toxicity endpoints?

*** Conventional Treatment: Dmean < 54Gy, V75Gy < 25%, V40Gy < 40% *** *** SRS: D20cc < 14 Gy*** *** SBRT: D20cc < 25 Gy *** *** Endpoint: rectal toxicity (fistulas)*** V40Gy <= 80-100% volume (Bladder Treatments - Geisinger) V50Gy < 50% volume (Bladder Treatments - Geisinger) V65Gy <= 35-50% volume (Bladder Treatments - Geisinger) V70Gy < 20-25% volume (Bladder Treatments - Geisinger) V50Gy <= 50% volume (Pelvis Treatments - Geisinger) V60Gy <= 35% volume (Pelvis Treatments - Geisinger) V65Gy <= 25% volume (Pelvis Treatments - Geisinger) V70Gy <= 20% volume (Pelvis Treatments - Geisinger) V75Gy <= 15% volume (Pelvis Treatments - Geisinger) V60Gy <= 50% volume (Pelvis Treatments - RTOG 0126) V65Gy <= 35% volume (Pelvis Treatments - RTOG 0126) V70Gy <= 25% volume (Pelvis Treatments - RTOG 0126) V75Gy <= 15% volume (Pelvis Treatments - RTOG 0126) Dmax <= 18.4 Gy (1 frac SBRS - TG-101 -proctitis/fistula) D20cc <= 14.3Gy (1 frac SBRS - TG-101 -proctitis/fistula) Dmax <= 28.2 Gy (3 frac SBRS - TG-101 -proctitis/fistula) D20cc <= 24 Gy (3 frac SBRS - TG-101 -proctitis/fistula) Dmax <= 38 Gy (5 frac SBRS - TG-101 -proctitis/fistula) D20cc <= 25 Gy (5 frac SBRS - TG-101 -proctitis/fistula) QUANTEC Analysis 3D-CRT: V50 <50% (<15% complication rate)

What are typical dose-volume constraints clinically acceptable for the Stomach? What are the toxicity endpoints?

*** Conventional Treatments: D100cc < 45 Gy, Dmax < 54 Gy *** *** SRS: D10cc < 11 Gy*** *** SBRT:D10cc < 18 Gy *** *** Endpoint: ulceration/fistula*** D100cc < 45 Gy (Abdomen Treatments - Geisinger) D100cc < 45 Gy (Esophagus Treatments - Geisinger) Dmax < 54 Gy (Pancreatic Treatments - Spalding/Mobius Chart) V50 Gy < 2% vol (Pancreatic Treatments - Spalding/Mobius Chart) V45 Gy < 25% vol (Pancreatic Treatments - Spalding/Mobius Chart) Dmax < 12.4 Gy (1 frac SBRS - TG-101 -ulceration/fistula) D10cc < 11.2 Gy (1 frac SBRS - TG-101 -ulceration/fistula) Dmax < 22.2 Gy (3 frac SBRT - TG-101 -ulceration/fistula) D10cc < 16.5 Gy (3 frac SBRT - TG-101 -ulceration/fistula) Dmax < 32 Gy (5 frac SBRT - TG-101 -ulceration/fistula) D10cc < 18 Gy (5 frac SBRT - TG-101 -ulceration/fistula)

What are typical dose-volume constraints clinically acceptable for the Spinal Chord? What are the toxicity endpoints?

*** Conventional Treatments: Dmax < 50 Gy *** ***SRS: Dmax < 14 Gy*** *** SBRT: Dmax < 30 Gy*** *** Endpoint: myelopathy (spinal cord dysfunction)*** Dmax <= 50 Gy (Abdomen Treatments - Geisinger) Dmax <= 50 Gy (Brain Treatments - Geisinger) Dmax <= 50 Gy (Esophagus Treatments - Geisinger) Dmax <= 50 Gy (Lung Treatments - Geisinger) Dmax <= 45 Gy (Lung Treatments - RTOG 0623) Dmax <= 50 Gy (Oral Cavity Treatments - Geisinger) Dmax <= 50 Gy (Head & Neck Treatments - Geisinger) Dmax <= 14 Gy (SRS - TG-101 - myelitis) D0.35cc <= 10Gy (SRS - TG-101 - myelitis) D1.2cc <= 7Gy (SRS - TG-101 - myelitis) Dmax <= 21.9 Gy (3 frac SBRT - TG-101 - myelitis) D0.35cc <= 18Gy (3 frac SBRT - TG-101 - myelitis) D1.2cc <= 12.3Gy (3 frac SBRT - TG-101 - myelitis) Dmax <= 30 Gy (5 frac SBRT - TG-101 - myelitis) D0.35cc <= 23Gy (5 frac SBRT - TG-101 - myelitis) D1.2cc <=14.5Gy (5 frac SBRT - TG-101 - myelitis) If treating for 1% risk of myelopathy ( SRS - Geisinger) Point Dose Max to Thecal Sac is 9.2 Gy D0.35cc < 10 Gy Dmax <= 14 Gy If treating for 3% risk of myelopathy (SRS - Geisinger) Point Dose Max to Thecal Sac is 11.5 Gy D<1.2cc < 7Gy Dmax <= 14 Gy If treating for 5% risk of myelopathy (SRS - Geisinger) Point Dose Max to Thecal Sac is 12.4 Gy D10% of subvolume < 10 Gy D0.35cc < 10 Gy Dmax <= 14 Gy QUANTEC Analysis 3D-CRT: Dmax < 50 Gy (0.2% complication rate) SRS (Single Fraction): 13 Gy (1% complication rate) SRS (Hypofractionation): 20 Gy (1% complication rate)

What are typical dose-volume constraints clinically acceptable for the Bowel? What are the toxicity endpoints?

*** Conventional Treatments: Dmax < 54Gy, D180cc < 35 Gy; D90cc < 45 Gy *** *** SRS: D10cc < 9 Gy*** *** SBRT: D10cc < 13 Gy *** ***Endpoint: bowel toxicity diarrhea, inflammation, ulceration*** Dmax <= 55 Gy (Abdomen Treatments - Geisinger) Dmax <= 60 Gy (Abdomen Treatments - MobiusChart - Duodenum) V45Gy <= 33% (Abdomen Treatments - MobiusChart - Duodenum) V45Gy <= 195cc -70% volume (Bladder Treatments - Geisinger) V45Gy <= 195cc (Pelvis Treatments - Geisinger) V40Gy <= 30% volume (Rectum Treatments - Geisinger) Dmax <= 50 Gy (Rectum Treatments - RTOG 0822) V40Gy <= 100cc (Rectum Treatments - RTOG 0822) V35Gy <= 180cc (Rectum Treatments - RTOG 0822) V45Gy <= 65cc (Rectum Treatments - RTOG 0822) Dmax <= 18.4 Gy (1 frac SBRS - TG-101 - colitis/fistula of Colon) D20cc <= 14.3 Gy (1 frac SBRS - TG-101 - colitis/fistula of Colon) Dmax <= 12.4 Gy (1 frac SBRS - TG-101 - Ulceration of Duodenum) D10cc <= 9 Gy (1 frac SBRS - TG-101 - Ulceration of Duodenum) D5cc <= 11.2 Gy (1 frac SBRS - TG-101 - Ulceration of Duodenum) Dmax <= 15.4 Gy (1 frac SBRS - TG-101 - enteritis Ileum/Jejunum) D5cc <= 11.9 Gy (1 frac SBRS - TG-101 - enteritis Ileum/Jejunum) Dmax <= 28.2 Gy (3 frac SBRT - TG-101 - colitis/fistula of Colon) D20cc <=24 Gy (3 frac SBRT - TG-101 - colitis/fistula of Colon) Dmax <= 22.2 Gy (3 frac SBRT - TG-101 - Ulceration of Duodenum) D10cc <= 11.4 Gy (3 frac SBRT - TG-101 - Ulceration of Duodenum) D5cc <= 16.5 Gy (3 frac SBRT - TG-101 - Ulceration of Duodenum) Dmax <= 25.2 Gy (3 frac SBRT - TG-101 - enteritis Ileum/Jejunum) D5cc <= 17.7 Gy (3 frac SBRT - TG-101 - enteritis Ileum/Jejunum) Dmax <= 38 Gy (5 frac SBRT - TG-101 - colitis/fistula of Colon) D20cc <=25 Gy (5 frac SBRT - TG-101 - colitis/fistula of Colon) Dmax <= 32 Gy (5 frac SBRT - TG-101 - Ulceration of Duodenum) D10cc <= 12.5 Gy (5 frac SBRT - TG-101 - Ulceration of Duodenum) D5cc <= 18 Gy (5 frac SBRT - TG-101 - Ulceration of Duodenum) Dmax <=35 Gy (5 frac SBRT - TG-101 - Ulceration of Duodenum) D5cc <= 19.5 Gy (5 frac SBRT - TG-101 - Ulceration of Duodenum) QUANTEC Analysis (Small Bowel in particular) 3D-CRT: V15 < 120 cc (<10% complication rate)

What are typical dose-volume constraints clinically acceptable for the Esophagus? What are the toxicity endpoints?

*** Conventional Treatments: Dmax < 54Gy; Dmean < 34 Gy *** ***SRS: Dmax < 15 Gy*** *** SBRT: Dmax < 35 Gy*** ***Endpoint: esophagitis (inflammation of esophagus)*** V50Gy < 40% volume (Abdomen Treatments - Geisinger) Dmean < 35 Gy (Head & Neck Treatments - RTOG 0920) V54Gy < 15% volume (Head & Neck Treatments - RTOG 0920) V45Gy < 33% volume (Head & Neck Treatments - RTOG 0920) Dmax <= 15.4 Gy (1 frac SBRS - TG-101- Stenosis/fistula) D5cc <= 11.9 Gy (1 frac SBRS - TG-101- Stenosis/fistula) Dmax <= 25.2 Gy (3 frac SBRS - TG-101- Stenosis/fistula) D5cc <= 17.7 Gy (3 frac SBRS - TG-101- Stenosis/fistula) Dmax <= 35 Gy (5 frac SBRS - TG-101- Stenosis/fistula) D5cc <= 19.5 Gy (5 frac SBRS - TG-101- Stenosis/fistula) QUANTEC Analysis 3D-CRT: Dmean < 34 Gy (5-20% complication rate)

What are typical dose-volume constraints clinically acceptable for the Kidneys? What are the toxicity endpoints?

*** Conventional Treatments: Dmean < 12Gy (total kidney), V23Gy < 32% (total kidneys), Dmean <= 18Gy (single kidneys) *** *** SRS: D200cc < 8 Gy*** *** SBRT: D200cc < 18 Gy*** ***Endpoint: renal dysfunction*** V12Gy <= 55% Total Kidney Volume (Abdomen Treatments - Geisinger) V20Gy <= 32% Total Kidney Volume (Abdomen Treatments - Geisinger) V23Gy <= 30% Total Kidney Volume (Abdomen Treatments - Geisinger) V28Gy <= 20% Total Kidney Volume (Abdomen Treatments - Geisinger) Dmean <= 15Gy Total Kidney Volume (Abdomen Treatments - Geisinger) V30Gy <= 67% vol (Esophageal Treatment - RTOG 0436) V23 Gy <= 100% vol (Esophageal Treatment - RTOG 0436) D200cc < 8.4 Gy (1 frac SBRS - TG-101- Both Renal Cortex) D66% < 10.8 Gy (1 frac SBRS - TG-101- Renal vascular trunk) D200cc < 16 Gy (3 frac SBRT - TG-101- Both Renal Cortex) D66% < 18.6 Gy (3 frac SBRT - TG-101- Renal vascular trunk) D200cc < 17.5 Gy (5 frac SBRT - TG-101- Both Renal Cortex) D66% < 23 Gy (5 frac SBRT - TG-101- Renal vascular trunk) QUANTEC Analysis 3D-CRT: V20 < 32% (<5% complication rate)

What are typical dose-volume constraints clinically acceptable for the Liver? What are the toxicity endpoints?

*** Conventional Treatments: Dmean < 35Gy*** *** SRS: D(at least 700cc) < 9 Gy*** *** SBRT: D(at least 700cc) < 20 Gy*** ***Endpoint: Hepatitis and RILD (Radiation Induced Lung Disease - can involve pneumonitis and fibrosis) IF WHOLE LIVER GTV*** Dmean < 32 Gy if no disease (Abdomen Treatments - Geisinger) Dmean <= 28 Gy if CP class A or HCC (Abdomen Treatments - Geisinger) V35Gy < 50% vol (Esophageal Treatment - RTOG 0436) V30Gy < 100% vol (Esophageal Treatment - RTOG 0436) D(at least 700cc) < 9.1 Gy (1 frac SBRS - TG-101 - basic liver function) D(at least 700cc) < 19.2 Gy (3 frac SBRT - TG-101 - basic liver function) D(at least 700cc) < 21 Gy (5 frac SBRT - TG-101 - basic liver function) QUANTEC analysis 3D-CRT: Dmean < 30 Gy (<5% complication rate) SRS (Hypofractionation): Dmean < 13 Gy (<5% complication rate)

According to ABRPhysicsHelp and TG-56, what are recommended QA tests for HDR afterloaders on a quarterly basis, after a source exchange of an Ir-192 source? What are the tolerances for each? In the context of a source exchange, what is should be done prior to the actual source exchange and performance of the QA tests? Summarize within a few sentences.

- Source Calibration Check -> measurement of dose within 3% of manufacturer estimated dose. - Timer Accuracy = Timer vs dose linearity -> 1% deviation from calculated slope. - Positional accuracy of source -> 1 mm - Battery Backup -> functional - Update TPS with source characteristics (source activity and calibration date). Essentially two things: (1) The vendor engineer's preventative maintenance inspection (PMI) (2) The source retrieval process, which includes . . .- authorized user signing for source. - Visual inspection of package damage. - Survey radiation levels from package and perform a wipe test. - Storage of shielded bucket in secure area.

What are typical dose-volume constraints clinically acceptable for the Bladder? What are the toxicity endpoints?

*** Conventional Treatments: Dmean < 65 Gy, V40Gy < 40% , V75Gy < 25%*** *** SRS: D15cc < 11 Gy*** *** SBRT: D15cc < 18 Gy *** ***Endpoint: Toxicity (loss of urinary control), cystitis/fistula*** V35Gy <= 50% volume (Anus Treatments - RTOG 0529) V40Gy <= 35% volume (Anus Treatments - RTOG 0529) V50Gy <= 50% volume (Anus Treatments - RTOG 0529) Dmax < 65Gy (Bladder Treatments) V45Gy <= 35% volume (HDR & Gynaecology [GYN] Treatments - Geisinger) Dmax <= 75 Gy (HDR & Gynaecology [GYN] Treatments - Geisinger) V65Gy <= 50% volume (Pelvis Treatments - Geisinger/RTOG 0126) V70Gy <= 35% volume (Pelvis Treatments - Geisinger/RTOG 0126) V75Gy <= 25% volume (Pelvis Treatments - Geisinger/RTOG 0126) V80Gy <= 15% volume (Pelvis Treatments - Geisinger/RTOG 0126) Dmean <= 40 Gy (Rectum Treatments - Geisinger) Dmax < 18.4 Gy (1 frac SBRS - TG-101- BladderWall cystitis/fistula) D15cc < 11.4 Gy (1 frac SBRS - TG-101- BladderWall cystitis/fistula) Dmax < 28.2 Gy (3 frac SBRT - TG-101- BladderWall cystitis/fistula) D15cc < 18.8 Gy (3 frac SBRT - TG-101- BladderWall cystitis/fistula) Dmax <38 Gy (5 frac SBRT - TG-101- BladderWall cystitis/fistula) D15cc <18.3 Gy (5 frac SBRT - TG-101- BladderWall cystitis/fistula) QUANTEC Analysis 3D-CRT: V65 < 50%

What are typical dose-volume constraints clinically acceptable for the Brain? What are the toxicity endpoints?

*** Conventional: Dmax < 60 Gy*** *** SRS: V12 Gy < 10 cc*** ***Endpoint: Necrosis (death of tissue)*** Dmax < 60 Gy (Brain Treatments - Geisinger) D5-10cc < 12 Gy (SRS - Geisinger) D10cc < 10 Gy (SRS - Geisinger) D10cc < 10 Gy (SRS - Mobius Chart) QUANTEC Analysis 3D-CRT: Dmax < 60 Gy (<3% complication rate) SRS (single Fraction): V12 < 10 cc (<20% complication rate)

What are typical dose-volume constraints clinically acceptable for the Bronchus?

*** SRS: D0.5cc < 14 Gy*** *** SBRT: D0.5cc < 21 Gy *** Dmax < 13.3 Gy (1 frac SBRS- TG-101 - Stenosis with atelectasis) D0.5cc < 12.4 Gy (1 frac SBRS- TG-101 - Stenosis with atelectasis) Dmax < 23.1 Gy (3 frac SBRT- TG-101 - Stenosis with atelectasis) D0.5cc < 18.9 Gy (3 frac SBRT- TG-101 - Stenosis with atelectasis) Dmax < 33 Gy (3 frac SBRT- TG-101 - Stenosis with atelectasis) D0.5cc < 21Gy (3 frac SBRT- TG-101 - Stenosis with atelectasis)

What are typical dose-volume constraints clinically acceptable for the Ribs? What are the toxicity endpoints?

*** SRS: D1cc < 22 Gy*** *** SBRT: D1cc < 35 Gy*** *** Brachy: D0.1cc < 42.5 Gy*** Endpoints: rib fracture Dmax < 30 Gy (1 SBRS - TG-101 - pain/fracture) D1cc < 22 Gy (1 SBRS - TG-101 - pain/fracture) Dmax < 36.9 Gy (3 SBRT - TG-101 - pain/fracture) D1cc < 28.8 Gy (3 SBRT - TG-101 - pain/fracture) D30cc < 30 Gy (3 SBRT - TG-101 - pain/fracture) Dmax < 43 Gy (5 SBRT - TG-101 - pain/fracture) D1cc < 35 Gy (5 SBRT - TG-101 - pain/fracture) D0.1cc < 42.5 Gy (APBI Brachy - CCCN)

What are typical dose-volume constraints clinically acceptable for the Trachea?

*** SRS: D4cc < 10 Gy*** *** SBRT: D4cc < 16 Gy *** Dmax < 20.2 Gy (1 SBRS - TG-101 - stenosis/fistula) D4cc < 10.5 Gy (1 SBRS - TG-101 - stenosis/fistula) Dmax < 30 Gy (3 SBRT - TG-101 - stenosis/fistula) D4cc < 15 Gy (3 SBRT - TG-101 - stenosis/fistula) Dmax < 40 Gy (5 SBRT - TG-101 - stenosis/fistula) D4cc < 16.5 Gy (5 SBRT - TG-101 - stenosis/fistula)

What are typical dose-volume constraints clinically acceptable for the Cauda Equina?

*** SRS: D5cc < 14 Gy*** *** SBRT: D5cc < 30 Gy *** Dmax < 16 Gy (1 frac SBRS- TG-101 - neuritis) D5cc < 14 Gy (1 frac SBRS- TG-101 - neuritis) Dmax < 24 Gy (3 frac SBRT- TG-101 - neuritis) D5cc < 21.9 Gy (3 frac SBRT- TG-101 - neuritis) Dmax < 32 Gy (5 frac SBRT- TG-101 - neuritis) D5cc < 30 Gy (5 frac SBRT- TG-101 - neuritis)

What are typical dose-volume constraints clinically acceptable for the Sacral Plexus? What are the toxicity endpoints?

*** SRS: D5cc < 14 Gy*** *** SBRT:D5cc < 23 Gy *** *** Endpoint: bone fractures, neuropathy*** Dmax <= 16 Gy (1 frac SBRS - TG-101 - neuropathy) D5cc <= 14.4 Gy (1 frac SBRS - TG-101 - neuropathy) Dmax <= 24 Gy (3 frac SBRT - TG-101 - neuropathy) D5cc <= 22.5 Gy (3 frac SBRT - TG-101 - neuropathy) Dmax <= 32 Gy (5 frac SBRT - TG-101 - neuropathy) D5cc <= 30 Gy (5 frac SBRT - TG-101 - neuropathy)

What are typical dose-volume constraints clinically acceptable for the Femoral Heads?

***CCCN: Dmax < 50 Gy; V45Gy < 25% *** V30Gy <= 50% volume for each (Pelvis Treatments - Geisinger) V40Gy <= 40% volume for each (Pelvis Treatments - Geisinger) V45 Gy <= 5% volume for each (Pelvis Treatments - Geisinger) Dmax <= 50 Gy for each (Pelvis Treatments - Geisinger) V30Gy <= 50% volume for each (Rectum Treatments - Geisinger) V40Gy <= 40% volume for each (Rectum Treatments - Geisinger) V45 Gy <= 5% volume for each (Rectum Treatments - Geisinger) Dmax <= 50 Gy for each (Rectum Treatments - Geisinger) Dmax <= 50 Gy for each (Rectum Treatments - RTOG 0822) V45Gy <= 25% (Rectum Treatments - RTOG 0822) V40Gy <= 40% (Rectum Treatments - RTOG 0822) D10cc <= 14 Gy for each (1 frac SBRS - TG-101 - Necrosis) D10cc <= 21.9 Gy for each (3 frac SBRT - TG-101 - Necrosis) D10cc <= 30 Gy for each (5 frac SBRT - TG-101 - Necrosis)

What are typical dose-volume constraints clinically acceptable for the Larynx?

***CCCN: Dmax < 66 Gy; Dmean < 42 Gy*** Dmax <= 66Gy (Oral Cavity Treatments - Geisinger) Dmean <= 50 Gy (Oral Cavity Treatments to for lower Aspiration Risk - Geisinger) V50Gy <= 27% volume (Oral Cavity Treatments - Geisinger) Dmax <= 66Gy (Head & Neck Treatments - Geisinger) Dmean <= 50 Gy (Head & Neck Treatments for lower Aspiration Risk - Geisinger) V50Gy <= 27% volume (Head & Neck Treatments - Geisinger) Dmean < 45 Gy (Pharynx Treatment - RTOG 0225)

What are typical dose-volume constraints clinically acceptable for the External Genitalia?

***CCCN: Dmean < 25 Gy*** V20Gy <= 50% volume (RTOG 0529) (Anus Treatments - Geisinger) V30Gy <= 35% volume (RTOG 0529) (Anus Treatments - Geisinger) V40 Gy <= 5% (RTOG 0529) (Anus Treatments - Geisinger)

What are typical dose-volume constraints clinically acceptable for the Brainstem? What are the toxicity endpoints?

***Conventional Treatment: Dmax < 54Gy*** *** SRS: Dmax < 15 Gy*** *** SBRT: Dmax < 31 Gy*** ***Endpoint: Necrosis or neuropathy*** Dmax < 64 Gy (Brain Treatments - Geisinger) D0.5cc < 10 Gy (SRS - Geisinger) Dmax < 15 Gy (SRS - Geisinger) D1cc <= 12 Gy (SRS - Geisinger) Dmax < 54 Gy (Pharynx - RTOG 0225) V60Gy < 1% vol (Pharynx - RTOG 0225) Dmax < 15 Gy (SRS - TG-101 - cranial neuropathy) D0.5cc < 10 Gy (SRS - TG-101 - cranial neuropathy) Dmax < 23.1 Gy (3 frac SRT - TG-101 - cranial neuropathy) D0.5cc < 18 Gy (3 frac SRT - TG-101 - cranial neuropathy) Dmax < 31 Gy (5 frac SRT - TG-101 - cranial neuropathy) D0.5cc < 23 Gy (5 frac SRT - TG-101 - cranial neuropathy) QUANTEC Analysis 3D-CRT: Dmax < 54 Gy (<5% complication rate) SRS (Single Fraction): Dmax < 12.5 Gy (<5% complication rate)

What are typical dose-volume constraints clinically acceptable for the Pharynx?

***Conventional Treatment: Dmean < 54 Gy*** Dmean < 50Gy (Breast Treatments - Geisinger) Dmean < 50Gy (Oral Cavity Treatments - Geisinger) Dmean < 50Gy (Head & Neck Treatments - Geisinger) Dmean < 54 Gy (Larynx Treatments - Caglar/Mobius Chart) D50Gy < 51% vol (Larynx Treatments - Caglar/Mobius Chart) D52Gy < 60% vol (Larynx Treatments - Caglar/Mobius Chart)

What are typical dose-volume constraints clinically acceptable for the Parotids? What are the toxicity endpoints?

***Conventional treatments: Dmean <26 Gy (single parotid)*** ***Endpoint: loss of parotid salivary function (xerostomia)*** D20cc <= 20 Gy if sparing both (Oral Cavity Treatments - Geisinger) Dmean <= 26 Gy for one if sparing one (Oral Cavity Treatments - Geisinger) D50% <= 30 Gy for for one if sparing one (Oral Cavity Treatments - Geisinger) D20cc <= 20 Gy for both (Head & Neck Treatments - Geisinger) Dmean <= 26 Gy for one if sparing one (Head & Neck Treatments - Geisinger) D50% <= 30 Gy for one if sparing one (Head & Neck Treatments - Geisinger) Dmean < 28 Gy for one if sparing one (Thyroid Treatments - RTOG 0912) V30Gy < 50% vol for one if sparing one (Thyroid Treatments - RTOG 0912) V20Gy < 20cc if sparing both (Thyroid Treatments - RTOG 0912) QUANTEC Analysis 3D-CRT: Dmean < 25 Gy (<20% complication rate)

What are typical dose-volume constraints clinically acceptable for the Penile Bulb? What are the clinical endpoints?

***Conventional: Dmean <= 52.5 Gy*** ***Endpoint: erectile dysfunction, pain/fracture*** Dmean <= 52.5 Gy (Prostate Treatments - Geisinger & RTOG 0126) Dmax <= 34 Gy (1 frac SBRS - TG-101 - Pain/fracture) D3cc <= 14 Gy (1 frac SBRS - TG-101 - Pain/fracture) Dmax <= 42 Gy (3 frac SBRT - TG-101 - Pain/fracture) D3cc <= 21.9 Gy (3 frac SBRT - TG-101 - Pain/fracture) Dmax <= 50 Gy (5 frac SBRT - TG-101 - Pain/fracture) D3cc <= 30 Gy (5 frac SBRT - TG-101 - Pain/fracture) QUANTEC Analysis 3D-CRT: V50 < 90% (<35% complication rate)

What are typical dose-volume constraints clinically acceptable for the Tongue?

***Dmax < 55 Gy (Pharynx Treatment - RTOG 0225)*** D1% < 65 Gy (Pharynx Treatment - RTOG 0225)

What are typical dose-volume constraints clinically acceptable for the Temporal Lobes?

***Dmax < 60 Gy (Pharynx Treatments - RTOG 0225)*** V65Gy < 1% vol (Pharynx Treatments - RTOG 0225)

What are typical dose-volume constraints clinically acceptable for the Mandible?

***Dmax < 70 Gy (Pharynx Treatment - RTOG 0225)*** D1cc < 75 Gy (Pharynx Treatment - RTOG 0225)

What are typical dose-volume constraints clinically acceptable for the T-M Joint?

***Dmax < 70 Gy (Pharynx Treatment - RTOG 0225)*** D1cc < 75 Gy (Pharynx Treatment - RTOG 0225)

What is a typical SRS/SRT treatment prescription for Brain metastases (single or multiple)?

***Geisinger - 15 Gy to 24 Gy in 1 to 3 fractions. ABRPhysicsHelp- 14 Gy to 22 Gy in a single fraction

According to ABRPhysicsHelp, how does target motion impact Single Field Uniform Dose (SFUD) plans for proton therapy?

"Blurring" or "Smearing" of dose over the target will occur but the effect is for the most part averaged out with multiple fields at varying entry angles.

According to ABRPhysicsHelp, What is the buzz word/description of the two hollow hemi-spherical electrodes, which are kept under vacuum and generate an electric field in a gap in between the pair, of a cyclotron accelerator? Since such accelerators are designed with magnets such that the hollow electrodes are between magnetic upper and lower poles, how do the particles accelerate in a cyclotron?

"dee" shaped. SPIRALS outward increasing energy from the middle of the "dee" electrodes and magnetic poles until reaching a revolution frequency limited by the diameter of the cyclotron.

According to ABRPhysicsHelp, What is the buzz word for the magnets used to laterally scatter a charged particle therapy beam using the spot scanning technique?

"wobbler" magnets

According to ABRPhysicsHelp, What is the approximate cost projection of installing a conventional proton therapy facility? What about facilities that utilize compact accelerator units?

$150 to $180 million ~$20 million

According to ABRPhysicsHelp, The concepts of machine QA for photon therapy accelerator systems and proton therapy accelerator systems are mostly the same. However, there are some differences. What are the Monthly QA checks that are unique to proton therapy accelerator systems? What equipment is normally utilized to do these measurements?

(1) "Proton-image" isocentricity (2) Ranges and Modulations Checks Use a multi-layer parallel plan ionization chamber -> analogous to a 1D-beam scanning water tank, which could also be used, but not as easily. take orthogonal films of steel ball with well know diameter and position.

According to ABRPhysicsHelp and Khan, How should the machine isocenter be position for an electron arc therapy treatment?

(1) As equidistant from surface contour, for all beam angles, for ideal agreement with dose calibration conditions, but its (2) depth needs to be greater than the maximum range of the electrons utilized to avoid excessive dose accumulation of electron dose at the isocenter.

According to ABRPhysicsHelp and MPPG.9A, what are the types of machine/program checks that should be done monthly and that are unique to Cyberknife, relative to Linac-based SRS/SBRT programs? Tolerances?

(1) Beam Symmetry -> Not really unique but tolerances are bit looser -> +-3 for 4cm field; +-4 for 6 cm field. (2) Imager Alignment -> Refers to the floor imagers angled 45 degrees with respect to floor surface and normal to respective sources CAX across treatment room. "Center" is defined according to "isopost" ("isocrystal") -> 1mm = center pixels +-2 pixels.

According to ABRPhysicsHelp and TG-59, what are the recommended training requirements for a physicist before he or her could become "involved" in HDR brachytherapy procedures? List them and elaborate within a couple sentences as necessary.

(1) Board-certified with HDR expertise/experience. (2) 1-3 weeks familiarizing self with HDR program, by shadowing procedures and talking with staff. (3) Be AT MINIMUM trained by vendor in operation of treatment unit and treatment planning system.

What are the primary treatment indications for SRS/SRT?

(1) Brain Metastases (2) Vestibular Schwannoma (Acoustic Nerinoma) (3) Glioma and other rarer brain tumors, both benign and cancerous (4) Pituitary Adenoma (5) Arterio-venous malformations (AVM) (6) Trigeminal Neuralgia (7) Functional Indications (Thalamotomy for tremor etc.) (8) Relapses or Retreated sites

According to Krauss, when it comes to generating a treatment plan for HDR prostate brachytherapy, what are different dosimetric approaches? List them and elaborate upon the advantages and disadvantage of each.

(1) CT-based planning Advantages: - more precise anatomic quantification of bladder and rectal doses Disadvantages: - Requires that the patient be moved multiple times to complete imaging studies and to move to shielded treatment room (2) Ultrasound-based planning: Advantages: - precise visualization of prostate capsule. - Can allow for completion of procedure without moving patient. Disadvantages: -Do not have advantages of CT and MRI. (3) MRI-based planning: Advantages: -unequivocally the highest image quality for dose planning. Disadvantages: - Have to worry about MR-compatibility of prostate implant and any necessary anesthesia equipment.

According to ABRPhysicsHelp and TG-147, what basic tests should be done on a daily basis?

(1) Check interlocks and field of views (2) Some localization test

According to an AAPM Online Learning Center Video Lecture, what are Patient Specific QA tests that may be typical for patients being treated with proton therapy?

(1) Compensator milling precision checks. -> for patient specific compensators. (2) Output factor checks -> for patient specific apertures .

According to ABRPhysicsHelp and MPPG.9A, what are the types of machine/program checks that should be done annually and that are unique to Tomotherapy, relative to Linac-based SRS/SBRT programs? Tolerances?

(1) Couch speed uniformity -> Not specific to SRS/SBRT, but unique test compared to Linac. Measured by using film to verify dose (opacity) does not vary along center of treatment plane when translating table. -> 2%. (2) Couch and Gantry Synchronization -> Not specific to SRS/SBRT, but unique test compared to Linac. Couch translation speed and gantry rotation speed for a given pitch should remain fixed throughout treatment. Measure using ion chamber to collect time varying waveform. -> each dose peaks should be 5cm apart +- 1mm.

According to ABRPhysicsHelp Summary of TG-101, what are key characteristics of a SBRT treatment plan? Any characteristics of dose distributions, treatment parameters, or machine/TPS software/hardware typically sought/selected in SBRT that are unique in comparison to conventional treatments? List as many as you can and elaborate upon each of them within a sentence if necessary.

(1) Delivers high biologically equivalent dose (BED) - usually 120-170 Gy within less than 10 fractions. (2) Tight target margins and dose fall-off for normal tissue sparing - done by prescribing dose to a low isodose line (typically 80%). (3) Many beams and typical to incorporate non-coplanar beams. (3) Large Dose to centroid of target - typically 125%-135% in excess of the prescription. (4) Dose fall-off from prescription isodose line and 50% isodose line is usually kept within 2cm. (5) usually 6MV is used (could use Flattening-Filter-Free beams if would like larger dose rate) since less penumbra due to less lateral electron transport. (6) Leaves with widths less than 5 mm desirable. (7) TPS should be equipped with dose calculation algorithm that adequately accounts for tissue inhomogeneities.

According to Wepassed!, What are the two types of electron guns that could be installed in a Linac? Be sure to call them by their "Buzz" names. What are the key differences between these two types of electron guns, in terms of operating principle?

(1) Diode Electron Gun -> Heated Cathode + Perforated Anode (2) Triode Electron Gun -> Heated Cathode + Perforated Anode + Grid. Diode and Triode -> IN Diode gun -> The static cathode-anode potential accelerate the electrons into waveguide. IN Triode Gun -> Voltage pulse to grid and static cathode-anode potential accelerate electrons into waveguide.

According to Wepassed!, What are the two different methods of heating an electron gun could employ? Be sure to use "Buzz" name/words. What is the temperature reached by each of the heating methods? What is the generated electron current per unit area for each heating method?

(1) Directly Heating = "Directly Heated Cathode" = Cathode and heater are one filament/coil of wire. 900 deg Celsius. 1 A/cm^2 (2) Indirectly Heating ->"Indirectly Heated Cathode = Cathode is a dispenser type and is typically a semi-hollow cylinder with the emitting end having a concave shape and the heating wire. 1100 deg Celsius. 100 A/cm^2

According to residency materials, how are T1-weighted MRIs useful for in the context of radiotherapy?

(1) Distinguishing fluids/edema from tumors (CSF and water looks dark), especially when using gadolinium contrast (2) Visualizing vascular structures and breakdown of blood-brain barrier, especially when using gadolinium contrast.

According to ABRPhysicsHelp, What are key characteristics of a "Multi Field Optimized" plan in the context of proton therapy? What is another name for this type of plan?

(1) Each field delivers varied dose distributions (summation of field dose is however homogenous). (2) "Inverse Planning" Inverse Modulated Proton Therapy (IMPT) plan

According to ABRPhysicsHelp, what are some safety precautions that should be implemented and safety considerations that should be addressed when administering I-131 ablation therapy? List and briefly elaborate within a couple sentences as necessary.

(1) Exposure to Adjacent rooms - need to make sure the treatment room housing the patient is shield. (2) Biohazard exposure control - treatment room need to be covered with plastic sheets since I-131 will be coming out through any patient perspiration and involved staff need to undergo bioassay to assess any iodine update.

According to ABRPhysicsHelp summary of TG-63, while one should always try to avoid irradiation through a prostheses, this may not always be possible. What are some of TG-63 recommendations for addressing this situation? List each of them and elaborate upon each possible course of action within a couple of sentences, if necessary.

(1) Figure out limitations of CT # vs electron density curve (2) Calculated using best TPS algorithm and correct of streak artifacts. (3) Use TG-63 data to do a hand-calc and compare to TPS calculation (4) Use diodes to measure body-exit dose or a TLD loaded in a catheter to measure dose to approximate body mid-point

According to ABRPhysicsHelp and TG-147, what basic test should be done on a monthly basis?

(1) Gating termination test (2) System communication test

According to ABRPhysicsHelp and MPPG.9A, what are the different levels of "supervision" a radiation oncologist and a "qualified" medical physicist can assert during the administration of radiation therapy services? List them and elaborate upon each within a couple of sentences as necessary.

(1) General Supervision -> assert direction and control but not required to have any sort of presence during the procedure. (2) Direct Supervision -> general supervision + present in the facility and immediately available to offer services throughout procedure. (3) Personal Supervision -> general supervision + physically present during the performance of procedure.

According to ABRPhysicsHelp Summary of TG-101, what types of information does the task group report provide? List them out.

(1) Guidelines for establishing a SBRT program. (2) Comprehensively present patient outcome and complication information. (3) Present guidelines for imaging, treatment planning, and quality assurance.

According to TG-40, What are the encouraged means in which a healthcare practices/organizations can audit their QA programs?

(1) Have periodic "reappraisal" of QA programs by persons within organization. (2) Have QA programs reviewed by external group of professionals (e.g. ACR). (3) Have periodic external monitoring of key programs aspects (TLDs/OSLDs of annual outputs). (4) Have the QA program incorporate a number of redundant monitoring/verification systems (e.g. chart checks, multiple detector systems)

According to ABRPhysicsHelp, what are some handy resources for QA of proton therapy accelerator systems?

(1) IAEA TRS 398 -> National TG-51 equivalent (2) ICRU 59 -> Proton dosimetry and Proton Physics report (3) ICRU 78 -> Prescribing and Reporting Recs for Proton therapy (4) TG-40 (5) TG-142 (6) TG-224 - Proton machine QA (7) TG-185 - IMPT commissioning

According to ABRPhysicsHelp and TG-147, In general, what are two key limitations of Radiofrequency localization and positioning systems?

(1) Implanted transmitters can migrate, complicating relationships established during simulation. (2) Relatively small field of view or operating range (~ 20cm for Calypso).

According to ABRPhysicsHelp, What are the two key purposes of the bending magnet system of a C-arm Linac?

(1) In a compact way, direct beam to patient so beam conducive for treatment. (2) Provide energy discrimination independent of the accelerating waveguide.

According to ABRPhysicsHelp summary of TG-106, what are potential sources of error in collected beam data?

(1) Inappropriate choice of detector (detector size, response dependencies, build-up region limitations, etc.) (2) Gantry Tilt (3) Excessive chamber leakage or incorrect gain applied to chamber (4) Incorrect chamber positioning or scanning direction (as for wedge profiles) (5) Scanning too quickly (6) Scanning through trays - can lead to artifacts

According to TG-50 (AAPM Report 72) and ABRPhysicsHelp, MLCs are not perfect blocks since they still can transmit radiation. What are three possible ways radiation can transmit through a two banks of leaves? Briefly describe each one and mention approximate magnitudes of beam transmission.

(1) Interleaf Transmission: radiation transmitting between the sides of two leaves. ~3% (2) Intraleaf Transmission: radiation transmitting through the entire leaf height (length of leaf along beam direction). ~2% (3) Leaf-end Transmission: radiation transmitting through the ends of leaves on opposite MLC banks, specifically in the context that the leaf ends are abutting. ~20%

According to ABRPhysicsHelp and MPPG.9A, what are the types of machine/program checks that should be done on a daily basis for Linac-based SRS/SBRT programs? Tolerances for each?

(1) Laser localization -> 1 mm (2) Collimator sizes -> 2 mm Unique****(3) Abridged Isocentricity test -> SRS = 1mm and SBRT = 1.5mm (4) IGRT Alignment test -> SRS = 1 mm and SBRT = 2 mm (5) Output Constancy -> +-3%

According to ABRPhysicsHelp summary of TG-76, What organs are typically affected by respiratory motion? List as many as reasonably possible.

(1) Lungs (2) Esophagus (3) Liver (4) Pancreas (5) Breast (6) Prostate (7) Kidneys

According to ABRPhysicsHelp, What are pediatric malignancies often treated using proton therapy?

(1) Medulloblastoma (2) Retinoblastoma

What are some typical benign spinal tumors that are usually treated with SRS/SRT/SBRT? List them. What are the typical radiation dose prescriptions when treating such tumors with such techniques?

(1) Meningioma (2) Schwannoma (3) Neurofibroma (4) Hemangioblastoma prescriptions are identical or VERY similar to that for cranial meningiomas: 20 Gy in 2 fractions or 21 Gy in 3 fractions or 18 Gy in 1 fraction

According to ABRPhysicsHelp, The concepts of machine QA for photon therapy accelerator systems and proton therapy accelerator systems are mostly the same. However, there are some differences. What are the Annual QA checks that are unique to proton therapy accelerator systems?

(1) Modulation checks Everything else seems pretty much analogous to that of photons systems.

According to an AAPM Online Learning Center Video Lecture, What are some prominent challenges in machine QA for proton therapy? List them out.

(1) Mores things to check -> proton delivery systems more complex. (2) Lack of methodology or forum to exchange ideas. (3) Proton systems are not robust yet -> still working out the bugs. (4) QA programs are highly dependent on vendor's system specs -> aka. type of delivery system dependencies, no software/hardware integration. (5) Limited dedicated QA devices. (6) Have to share one proton beam among 4 to 5 treatment rooms.

According to ABRPhysicsHelp, What kind of routine QA needs to be done for Gamma Knife Units? If need a basic overview what needs to be done, what resource can you refer to?

(1) Needs QA specific for helmets ---- helmet factors, helmet collimation alignment, etc.. (2) Needs QA unique to teletherapy machines (such as Co-60 teletherapy) --- Shutter Effect assessment, timer accuracy, transmission through shielding, etc. (3) Needs more or less dosimetry QA typical for Linac --- outputs, field size correction factors, beam profiles, etc. Refer to TG-42

According to ABRPhysicsHelp and TG-147, In general, what are two key limitations of dual camera optical tracking systems?

(1) Only tracks surface which may not be adequately correlated to internal motion. (2) Patient's clothes and hair may not be reflective enough to the cameras.

According to Wepassed!, what are the two types of cathodes that could be used in the electron gun of a Linac? Be sure to mention "Buzz" words and a few key properties of both of them. What is the heating method of the electron gun typically utilized for each cathode type?

(1) Oxide Cathodes -> - lower operating temperature (900 deg Celsius) - lower current density (1 A/cm^2) - Barium or Thorium with a Tungsten (W) coated with Barium or Thorium Oxide. - Direct heating (2) Dispenser Cathodes -> - higher operating temperature (1100 deg Celsius) - higher current density (100 A/cm^2) - Tungsten (W) impregnated with Barium, Alumina, and Calcium (BAC) - Indirect heating

According to ABRPhysicsHelp, how are PET scans following proton therapy treatment acquired these days in a clinic? What is the buzz word for each method? What is one key advantage for each?

(1) PET detectors installed on a proton gantry -> "Online (In-Beam) Monitoring" -> maximize signal by taking advantage of short-lived radioactive isotopes. (2) Patient moved to dedicated PET/CT -> "Offline Monitoring" -> can utilize more sophisticated PET scanner systems.

According to ABRPhysicsHelp and MPPG.9A, what are the types of machine/program checks that should be done annually and that are unique to Cyberknife, relative to Linac-based SRS/SBRT programs? Tolerances?

(1) Path Verification -> verifying all positional nodes along a set of nodes ("path") result in robot pointing direction (beam CAX) intersecting with the tip of an "isopost" ("isocrystal") for all deliverable beams. (2) Auto QA Baseline -> Recheck baseline for center of radiographic shadow for AQA test.

According to ABRPhysicsHelp and TG-147, what are few clinical applications of dual camera infrared tracking systems?

(1) Patient monitoring of position during treatment. (2) Positioning of patient for treatment (3) Management of respiratory motion.

According to ABRPhysicsHelp, What are the two generally accepted categories of clinical situation for which proton therapy is deemed to have an therapeutic advantage over photon therapy? What is a corollary of these two categories? What two other categories of usefulness could be extrapolated from this corollary?

(1) Pediatric patients - due to dose sensitivity of developing organs (2) Adult/pediatric patients with tumors close to critical structures. Corollary: proton plans dose fall-off can be made much steep/sharper than photon plans (1) Patients who would more likely be cured with dose escalation (Uveal melanoma, unresectable sarcomas). (2) Patients who would greatly benefit from normal tissue sparing (prostate cancer, medulloblastoma).

According to ABRPhysicsHelp summary of TG-106, What should be the bare minimum of commissioning data that should be measured for electrons? What additional commissioning data should be acquired beyond the bare minimum, and under what scenarios should these additional data be acquired (think MPPG 5a.)?

(1) Percent depth dose values (2) In-plane and cross-plane profiles (3) Cone-factors (4) Tray Factors (5) Virtual Source Positions EXTRA: (1) Cutout Factors --- Will definitely need them but collecting such data only makes sense if you anticipate common/simple shapes that will be used regularly. (2) Vendor data specific for TPS algorithms utilizing heterogeneity corrections --- Will be needed if plan on using such algorithms.

According to ABRPhysicsHelp summary of TG-106, What should be the bare minimum of commissioning data that should be measured for photons? What additional commissioning data should be acquired beyond the bare minimum, and under what scenarios should these additional data be collected (think MPPG 5a.)?

(1) Percent depth dose values (2) in-plane and cross-plane profiles (3) wedge factors (4) MLC data (interleaf and intraleaf leakage, penumbra, tongue and groove effect, etc.) (5) Scatter Factors (6) Tray Factors EXTRA: (1) Heterogeneity Data - If TPS Calculation algorithm capable of applying heterogeneity corrections. - HU vs Electron Density Curve - Mass Density Tables (Acuros) (2) IMRT/VMAT Data - If Linac will be used for IMRT/VMAT treatments. - DLGs measurements. - MLC interleaf/intraleaf transmission. - Leaf timing (if Tomotherapy).

According to ABRPhysicsHelp, kilovolt electrode tubes were used for radiation therapy until around what time? What was the maximum energy of these tubes around that time?

Around World War II; 300 kVp

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of Stereotactic accessories and lockouts? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Daily and Annually; Functional Same as TG-142

According to ABRPhysicsHelp and Khan, what are well known clinical treatment applications of Total Skin Irradiation (TSI)?

Mycosis fungoides; other cutaneous lymphomas.

According to ABRPhysicsHelp, When would a two different scatters be useable/desired in a passive scattering system of a particle therapy system? Such a system would be said to a _______ ___________ system. Fill in the blank

For larger fields: double scattering

According to ABRPhysicsHelp, When would a single scatter be useable/desired in a passive scattering system of a particle therapy system? Such a system would be said to a _______ ___________ system. Fill in the blank

For smaller fields; single scattering

According to residency materials, how are FLAIR MRIs useful for in the context of radiotherapy?

Good for identifying pathology more readily visible when signals from normal bodily fluids are suppressed.

According to ABRPhysicsHelp, what is the definition of the "phase III" of a clinical trial? Describe within a couple of sentences, as necessary.

Is the state of a clinical trial during which studies are performed to ascertain if a treatment is BETTER THAN ANOTHER STANDARD TREATMENT. Study is often RANDOMIZED, and cohort consists of a large number of people, such that DATA IS STATISTICALLY SOUND.

According to ABRPhysicsHelp and TG-179, which medical accelerator vendor, IGRT systems employ MV-CBCT?

Siemens Artiste

According to ABRPhysicsHelp, what is the Circulator of a conventional-C arm Linac? Where does it approximately sit relative to the treatment room or Linac itself?

System that prevents the microwaves originally from the klystron and entering the waveguide transport system from reflecting back into the Klystron and RF Driver. It is part of the waveguide transport system after the Klystron. It is located in the stand.

What are typical dose-volume constraints clinically acceptable for the Pelvic Bones?

V10Gy <= 90% volume (HDR & Gynaecology [GYN] Treatments - Geisinger) V40Gy <= 37% volume (HDR & Gynaecology [GYN] Treatments - Geisinger)

What are typical dose-volume constraints clinically acceptable for the Peritoneal Cavity?

V45Gy < 195 cc (Abdomen Treatments - Geisinger)

According to ABRPhysicsHelp, When wer Van De Graaff Generators phased out of use in radiotherapy applications?

With the advent of Co-60 teletherapy units in the 1950s.

According to ABRPhysicsHelp and TG-100, what is a "failure mode"?

a pathway a process can "fail"

According to ABRPhysicsHelp, what is the basic construction of a Thyratron? What is the voltage limit of a Thyratron and the frequency limit of switching on and off?

a pressurized tube filled with hydrogen gas that ionizes to form a conductive plasma that serves to charge circuits. ~10 kV; ~6 microseconds

Does the radiation light field tend to underestimate or overestimate a radiation field defined by round-ended MLC leaves?

underestimate

According to ABRPhysicsHelp, what is the precision of MLC leaf positioning often quoted by manufacturers?

0.1 mm to 1 mm

According to TG-59, in the event that a 10 Ci Ir-192 HDR source fails to retract and manual retraction is required to the point staff has to enter the room, what is a reasonable limit for the effective dose equivalent to personnel?

0.5 Sv (500 mSv) = 10 times the occupational dose limit.

According to ABRPhysicsHelp and TG-100, What are three characteristics of something (a process, a service, etc.) that define "quality"?

1. Aspects that take into consideration patients or clinics medical, psychological, and economic goals. 2. Meet standards of practice 3. Freedom from errors and mistakes

According to ABRPhysicsHelp and a paper by Ford et. al titled "A streamlined failure mode and effects analysis" (2014), what were the top ten failure modes identified in this report, ordered from highest risk priority number to lowest risk priority number

1. Delay in film check 2. No pacemaker consent and/or protocol 3. Failure to contour OAR 4. Pregnant patient simulated without knowledge of pregnancy. 5. Tomotherapy blocks turned off 6. Therapists unaware of prescription or written directive change. 7. Unclear setup instructions from simulation 8. Prior treatment records unavailable 9. Incorrect table angels entered into the record and verify system. 10. Planner not sure if physician contouring is complete.

According to ABRPhysicsHelp and TG-100, What are the 3 types of "failure modes"? Elaborate briefly upon each of them?

1. Errors: failures from acts of commission or omission that incorrected execute intended action required by process. 2. Mistake: failures due to incorrect intentions or plans that, even if executed perfectly, would fail to achieve goal. 3. Violation: failures due to intentionally not following procedures or sabotaging them in order to achieve intended goal

According to ABRPhysicsHelp and TG-100, What are the top nine major causes of failure in radiotherapy sorted from highest occurrence rating to lowest occurrence rating?

1. Human Failure 2. Lack of standardized procedures 3. Inadequate training 4. Inadequate communication 5. Hardware/Software Failure 6. Lack of Resources 7. Design Failure 8. Inadequate Commissioning 9. Defective Materials/Tools

According to ABRPhysicsHelp, what are some common concerns that arise when treating obese patients with radiation therapy? List the concerns and briefly elaborate upon each within a couple of sentences.

1. Machine weight limits -> CT simulator couches and treatment couches usually have weight limits on the order of 350 to 450 lbs. 2. Skin folds and panniculus (fatty tissue folds)-> can be sites of severe skin reactions unless pull back using tape or another method to flatten out folds in a reproducible way. 3. Reduced SSD -> extra tissue could mean less distance from treatment head to patient surface, which can increase likelihood of collisions.

According to ABRPhysicsHelp, what are key needs of patient positioning should be considered when designing a positioning approach for a patient? List them, and briefly mention some techniques or devices that can help fulfill these key needs?

1. Patient Comfort -> knee bolster, hand ring, head pillow. 2. Reproducibility -> belly board, supine/prone breast boards. Compression paddles. Bladder filling. Patient attire. Patient instructed positioning (head turning). 3. Safety -> limiting gantry/couch positions to prevent possible collisions. Restraints to secure patient in a compromised coordination or confused state. 4. Target Access -> Really a need that always considered in the examples already provided.

According to ABRPhysicsHelp and TG-100, what are the two major, and distinctive, components of a quality management program? Elaborate briefly upon both.

1. Quality Control (QC) - procedures that help achieve a desired level of quality - manage quality 2. Quality Assurance (QA) - procedures that help demonstrate that the desired level of quality has been achieved and maintained.

According to ABRPhysicsHelp and your own experience, what are some methods for creating space between rectal and irradiated areas during pelvis treatments? List them and elaborate upon each within a couple of sentences.

1. SpaceOars hydrogel -> special solidifying gel is inserted via trans-perineum needle, between the rectum and anterior tissue. 2. (Transrectal) Endorectal Balloons -> saline filled balloon inserted into rectum.

According to ABRPhysicsHelp, What kinds of shielding are usually used (or at least considered) when treating total skin electron cases? List them and briefly elaborate if necessary within a sentence. What material is usually used?

1. top of scalp ***2. eyes - lead contacts under eyelids, since can also harbor disease. 3. nails small pieces of lead

According to ABRPhysicsHelp and your own experience, what is "busy" daily case load for a Cyberknife unit? How long does it take to typically deliver a patient fraction?

About 6 to 8 patients a day. ~30 mins to an hour.

According to ABRPhysicsHelp, What are the names of the two bending magnet types? Give a brief description of design. What is the consequence of each on the electron beam? Which one does Varian use?

Achromatic and Chromatic Achromatic Bending Magnet: bends electron beam by 270 degrees. Consequence: Pencil-Beam Geometry Preserved - electrons of electron beam emerge from arc trajectory in same orientation as they each were upon entry of the bending magnetic. Chromatic Bending Magnet: bends electron beam by 90 degrees. Consequence: Pencil-Beam Geometry not Preserved - electrons of electron beam emerge from arc trajectory in orientations different from their entry into the bending magnetic. The orientations the electrons are dependent upon the insertion angle and position of the beam into the bending magnetic. Varian uses the Achromatic bending magnet

According to ABRPhysicsHelp, what are typical prescriptions of I-131 when administering I-131 ablation therapy? Be sure to mention the clinical indications for the various prescriptions. Is there any variations in prescription on a patient by patient basis? If someone wanted to vary prescriptions on a per patient-basis, what is considered the most precise way of determining the prescription for a specific patient?

Administered after tumor resection -> 30 mCi to 150 mCi Administered for metastases or recurrences -> 150 to 250 mCi They could, but typically facilities use fixed prescriptions for a clinical indication, such as 75 mCi tumor resected cases 200 mCi for recurring cases. Most precise method is to do a I-124 PET scan uptake study for patient to determine how much activity is needed.

According to Krauss, How many needles are typically implanted during a HDR prostate procedure? What are the typical dosimetric coverage to the prostate and the tolerances imposed for OARs?

15 to 20 needles. Similar to LDR Prostate -> V100% >95%; V150% < 30% ; V125% < 60% Urethra -> V110% < 5% Rectum -> D1cc < 75% Bladder -> D1cc <75%

According to Krauss, How long does it usually take to deliver a HDR prostate brachytherapy treatment? What are typical prescriptions (including accompanying treatment modalities) that utilize HDR prostate Brachy?

15-25 minutes. External Beam with HDR prostate boost -> 45 Gy in 25 fractions of external beam + 15Gy in a single fraction of HDR. Stand-alone HDR prostate brachy -> 27 Gy in 2 fractions, each fraction spaced by at least 6 hours. PRESCRIPTION CAN HOWEVER WIDELY VARY.

According to ABRPhysicsHelp and Google what is the energy of kilovoltage machines used for "Orthovoltage" therapy? What is "Orthovoltage" therapy exactly?

150-300 kVp It is the treatment of superficial lesions within 2cm of surface. While could be used for certain skin treatments, it is likely to be used for intra-operative procedures.

Given your experience at CCCN, what is a typical fractionation scheme for treating keloids? What modality is typically used?

16Gy in 4 fractions, a single fraction per day. electrons.

What are typical prescription doses for treating tumors causing spinal cord compression with SBRT radiation techniques?

18 to 24 Gy in single fraction

According to ABRPhysicsHelp summary of NCRP 151 and McGinley's "Shielding Techniques", How many Co-60 sources does a gamma knife unit typically have? What is the combined activity at the time of source placement?

192-201; 6500 Ci

According to ABRPhysicsHelp and TG-179, how many images per degree does a kV-CBCT typically take?

2 images per degree

According to ABRPhysicsHelp and TG-40, what is the recommended frequency for ADCL calibration of an ion chamber used for reference dosimetry?

2 years

According to ABRPhysicsHelp and TG-40, what is the recommended frequency for inspecting the reading linearity of an ion chamber used for reference dosimetry? What is the recommended tolerance?

2 years; 0.5%

According to ABRPhysicsHelp, a study performed in 2003 (Goitein, M, Jermann, M) found that proton therapy was approximately how much more expensive than photon therapy?

2.4

What is a typical SRS/SRT treatment prescription for Cranial meningiomas?

20 Gy in 2 fractions or 21 Gy in 3 fractions.

According to ABRPhysicsHelp and Wikipedia, what is the energy of kilovoltage machines used for "Grenz-ray" therapy? What is "Grenz-ray" therapy exactly?

20 kVp and below Basically the treatment of skin disorders that occur within 2mm depth from skin surface, such as seen in the epidermis.

According to ABRPhysicsHelp, Due to the efficiency limitations of the target and the attenuation of flattening filters, how many times higher does a electron beam current need to be if a C-arm Linac is to operate in photon mode (to produce photons rather than just using the electron beam)?

200-1000 times higher (~600 times higher)

According to ABRPhysicsHelp and TG-179, What is the typical photon energy utilized for MVCTs?

3.5 MV (not the treatment energy of 6 MV)

According to ABRPhysicsHelp, what is the typical prescription for Whole Brain treatments with Hippocampal sparing, if one is following trail protocol? By the same token, what are some key dose constraints on the treatment target and OARs?

30 Gy in 10 fractions to the whole brain minus hippocampus. (1) Brain, nerves and chiasm should not receive more than 125% of prescription (less than 37.5 Gy) (2) Hippocampus max dose less than 16 Gy. (3) total Hippocampus volume (D100%) should be less than 9 Gy.

What is the typical treatment regiment and technique for palliative pelvis treatments?

3DCRT driven 4-field box with optional boost: 45 Gy in 25 fractions + 5.4 Gy to 9 Gy in 3 to 5 fractions for a total of 50.4 Gy to 54 Gy.

What is the typical treatment regiment and technique for treating heterotopic ossification, palliative bone malignancy, and secondary bone marrow malignancy?

3DCRT or AP/PA fields delivering 7 Gy to 8 Gy in a single fraction.

According to ABRPhysicsHelp, the energy of the Co-60 gamma emissions is similar to the average energy produced by a ________________ (1). Fill in the blank.

4 MV linac.

According to ABRPhysicsHelp and Khan, what is the recommended "scanning field width" (width of field moved along an arc) of an electron beam for the delivery of electron arc therapy? What is the reasoning for this recommendation? Are there any consequences that could be considered disadvantageous if abiding by this recommendation?

4-8cm field size. Smaller field sizes allow for (1) improved normal incidence -> simplifying dosimetry. (2) dose per arc has less dependence total arc trajectory. Limited to lower dose rate and generate more x-ray contamination.

According to ABRPhysicsHelp and Google what is the energy of kilovoltage machines used for "Superficial" therapy? What is "Superficial" therapy exactly?

50-150 kVp It is the treatment of skin cancer and other skin conditions within 5 mm from from the skin surface. Also could encompass electronic brachytherapy treatments.

According to ABRPhysicsHelp and Google what is the energy of kilovoltage machines used for "Supervoltage" therapy? What is "Supervoltage" therapy exactly?

500-1000 kVp It seems to be the predecessor of modern MV linacs in that they were used to treat disease/lesions deeper that 2cm from surface. There does not seem to be much more info that is easily accessible on the subject, but apparently is not a very practical modality since such voltages would result in electrical arcing within kilovoltage units.

According to ABRPhysicsHelp, What is a typical/historical treatment regime for Ocular Melanoma delivered with proton therapy?

70 GyRBE in 5 fractions (14 GyRBE per fraction).

According to ABRPhysicsHelp, What is a typical/historical treatment regime for low-stage prostate cancer delivered with proton therapy?

75 GyRBE in 46 fractions (1.63 GyRBE per fraction).

How would you describe a cyclotron in one sentence?

A cyclic accelerator for which the electric field is alternated while the magnetic field is kept constant to accelerate particles to a specific energy limited by the radius of a circular orbit limited by the bounds of the accelerator.

How would you describe a synchrotron in one sentence?

A cyclic accelerator for which the magnetic and electric fields are synchronized with a particle beam.

According to ABRPhysicsHelp, how should one describe the machine design of a Gamma Knife unit? Describe within a few sentences. What are key advantages and disadvantages of the Gamma Knife in comparison to other stereotactic treatment methods? Describe a couple of Gamma Knife models available and their unique features.

A helmet-like apparatus that is placed on a patient's head. The helmet features about 192-201 channels, each containing a Co-60 seed, and each collimated radiation to at the isocenter of the helmet. Advantages: (1) Perhaps most precise stereotactic treatment system - ~0.3 mm precision. Disadvantages: (1) Have to worry about radioactive sources. (2) limited assortment of field sizes - 4 to 20 mm collimators. Elekta Perfexion System - 3 collimators built into unit (4, 8 , 16 mm) that can be utilized without exchanging helmets. Elekta Icon System - Uses CBCT and IR monitoring for patient frameless (mask based) radiosurgery.

According to Wepassed!, what are log files in the context of MLC systems in Linacs? Describe within a couple of sentences. How can these log files be used? List each, and elaborate upon each within a couple of sentences as necessary.

A machine record of actual leaf positions during the execution of a plan or performance script by the Linac. They ultimately enable one to compare actual leaf positions to planned leaf positions. (1) Could be saved as auditable records for the machine. (2) Could be used for MLC diagnostics and machine QA. (3) Could be used for pre-treatment QA.

According to ABRPhysicsHelp and Wikipedia, in a single sentence, what is the basic design and operating principle of a Betatron? What types of radiation beams can the machine produce? What is a Betatron's physically mechanistic equivalent?

A machine that accelerates an electron current from a filament though magnetic induction within a doughnut (torus) vacuum tube electron beam or a photon beam if there is a target. a transformer with the tube being the secondary induction coil.

According to ABRPhysicsHelp, How is the pencil-size cross-section of the electron beam maintained within the accelerating waveguide?

A magnetic field generated by a solenoid coil running the length of the accelerating waveguide.

According to ABRPhysicsHelp, What is a Magnetron system? What are some of their key characteristics often worth considering in the context linear accelerator designs?

A microwave power generator that employs a cathode electrons source, a immersive magnetic field, and a enclosed-ring wall with carved cavities and spatially alternating regions of charge. Electrons emitted from the cathode spiral towards the charge wall, resulting in a resonant phenomenon with the cavities that generates microwaves. Key characteristics worth considering: (1) does not need a RF Driver (2) frequency of generated microwaves not stable (because of reflections from transport waveguides) (3) Limitations of output power (hence limitations of output energy)

According to ABRPhysicsHelp, what is the RF driver of a conventional-C arm Linac? Where does it approximately sit relative to the treatment room or Linac itself?

A system between the Pulse Modulator and the Klystron that converts the ~3 GHz voltage pulses from the PFN to ~3 GHz microwaves.

According to ABRPhysicsHelp, what is the Accelerator Electron Gun of a conventional-C arm Linac? Where does it approximately sit relative to the treatment room or Linac itself? What are the components of the Accelerator Electron Gun and the basic function of each?

A vacuumed system that provides a PFN-pulsed, electron density-controlled, pencil-beam of electrons into the accelerator waveguide. The electron-density of each pulse set by the grid determines the dose rate, and the frequency of the pulses set by the PFN ensuring proper timing of the electrons insertion with the Klystron microwaves inserted into the accelerator waveguide. It sits above the linac stand, close to the treatment room wall and just prior to the accelerator waveguide.

According to ABRPhysicsHelp and TG-147, if a peripheral localization and positioning device has a kind of reference point inherent in the system, how should that reference point be evaluated during system QA? How frequently should that reference point be evaluated? What are recommended tolerances? Explain the general idea in an sentence for each question.

A well understood correlation between the system's reference point and the machine's radiation isocenter should be established - the system's reference point "calibration" to radiation isocenter. The frequency of QA of this correlation should be as frequency as QA of radiation isocenter - Which typically daily to some level. The peripheral system reference point should correlate to the machine's radiation isocenter within 1 mm (SRS/SBRT) or 2 mm (conventional).

What is the typical prescription dose for treating Spine-proximal cancer with SBRT radiation techniques?

ABRPhysicsHelp & Geisinger - 1) 5 x 7 Gy to 35 Gy 2) 5 x 8 Gy to 40 Gy

What is the typical prescription dose for treating Liver cancer (such as Hepatocellular carcinoma) with conventional treatment techniques (IMRT and 3DCRT) and SBRT radiation techniques?

ABRPhysicsHelp & Geisinger - 4 x 15 Gy to 60 Gy (RTOG Liver Protocol 0438)

According to ABRPhysicsHelp and own experience, what are the typical fractionation schemes for Total Skin Electron (TSE) treatments?

ABRPhysicsHelp - 36 Gy in 200cGyx18fxs + possible boosts to perineum, scalp, palms, and soles. Usually 2 fractions per week

According to ABRPhysicsHelp and own experience, what are the typical fractionation schemes for Craniospinal Irradiation treatments?

ABRPhysicsHelp - 36 Gy in 200cGyx20fxs + optional boost to tumor bed of 18 Gy in 180cGyx10fxs to total of 54 Gy.

According to ABRPhysicsHelp and own experience, what are the typical fractionation schemes for Hodgkin's lymphoma treatments via mantle fields?

ABRPhysicsHelp - 36 to 40 Gy in 18 to 20fxs, respectively, for adults. 15 to 24 Gy in 10 to 16 fractions, respectively, for children

What is the typical prescription dose for treating Gynecological/Uterus pelvis cases with conventional radiation techniques (IMRT or 3DCRT)? Brachy?

ABRPhysicsHelp- EB-3DCRT primary & boost + LDR Brachy: 40 Gy whole pelvis + 20 Gy split pelvis EB, then 20Gy Cs-137 LDR implant, two 48 hour implant sessions separated by 2 weeks. Geisinger & ABRPhysicsHelp - EB + optional HDR Brachy: 45 Gy in 15 fractions to 55 Gy in 25 fractions external beam + optional 3 to 5 fractions of T&R HDR (Ir-192) to 15 Gy to 25 Gy. Surgical Resection + HDR Brachy: hysterectomy (uterus removed) then 15 Gy to 25 Gy of Vaginal Cylinder HDR (Ir-192) to vaginal cuff in 3 to 5 fractions. CCCN - EB + HDR Brachy: 45 Gy in 25 fractions external beam + 5 fractions of T&R HDR (Ir-192) to 25 Gy. Surgical Resection + HDR Brachy: hysterectomy (uterus removed) then 15 Gy of Vaginal Cylinder HDR (Ir-192) to vaginal cuff in 3 fractions.

What is the typical prescription dose for treating Lung cancer with conventional treatment techniques (IMRT and 3DCRT) SBRT radiation techniques? Brachy techniques?

ABRPhysicsHelp- SBRT: 4 x 12 Gy to 48 Gy (RTOG Lung protocol 0915) 3DCRT fields + 3DCRT boost: 40 Gy in 20 fractions + boost of 20 Gy in 10 fractions for a total of 60 Gy. LDR Permanent Lung Mesh: scale of 100Gy to 0.5 cm depth, using array of Pd-103 sources. Geisinger- SBRT: 3 x 18 Gy to 54 Gy other prescriptions similar to that of CCCN CCCN- 3DCRT fields + optional 3DCRT boost: 45 Gy in 25 fractions + boost of 18 Gy in 10 fractions for a total of 63 Gy VMAT: 60 to 66 Gy in 30 to 33 fractions.

According to ABRPhysicsHelp summary of TG-76, What are motion encompassing techniques in the context of respiratory motion management? Describe their fundamental principle within a couple of a sentences. What type of imaging scans are performed when employing such techniques? List the typical imaging scans and generate imaging sets and briefly describe each of them within a couple of sentences.

Basically any technique that attempts to accounts for motion by using larger treatment margins determined based off of imaging scans performed during treatment SIMULATION. (1) Slow CT Scans - averages tumor's motion in composite CT image set. (2) A full inhale and full exhale CT scan pair - gives a sense of full extent of tumor movement in a patient's respiratory cycle. (3) Binned 4DCT image sets - correlates acquired images to external surrogate tracking respiratory phases. The imaging procedure can group or "bin" acquired images to respiratory phases in either two of the following ways: Prospective binning - where images acquired ONLY during certain respiratory phases to limit imaging dose; or Retrospective binning - where images are acquired during all phases, all of which are sorted into phase groups after acquisition (4) MIP-Maximum Intensity Projection image set - requires a Binned 4DCT image set. Essentially, each imaging slice is a composition of the highest value pixels found in that imaging slice throughout all of the the respiratory phases. This results in giving a sense of the full volume encompassed by a moving, high density tumor immersed in relatively less dense tissue, which is usually beneficial in lung cases. (5) MinIP - Minimum Intensity Projectio image set - requires a Binned 4DCT image set. Essentially each imaging slice is a composition of the lowest vlaue pixels found in that imaging slice throughout all of the respiratory phases. This results in giving a sense of the full volume encompassed by a moving , low density tumor immersed in relatively more dense tissue, which is usually beneficial in liver cases.

According to ABRPhysicsHelp summary of TG-106, if a manufacturer of a medical linear accelerator provides "Golden Beam data" (standardized data set that attempts to match beam characteristics among instances of the same linac model), how would that change the commissioning process for a clinical linacs? Should this data be used to model the linac in the TPS system?

Beam data collected is to demonstrate that the clinic linac characteristics resembles the golden beam data. Whether the physicist uses the golden beam data directly in the TPS system or the clinic's acquired data is left to the judgement of the physicist. TG-106 cautions against the direct use of golden beam data for the TPS.

According to ABRPhysicsHelp, what is the motivation for considering the delivery of Hippocampal sparing whole brain radiotherapy? Describe within a couple of sentences and mention any pertinent resources.

Because the alternative, just conventional whole brain radiotherapy, has been show to cause cognitive decline within a relatively short period of time (~ 6 months). The hippocampus is known to play a critical role in memory formation and after the NRG-CC001 trial, it is believe sparing it will help avoid the occurrence of neuro-cognitive decline.

According to ABRPhysicsHelp, what are the benefits of a standing waveguide design over a traveling waveguide design? What are the pitfalls in relation to a traveling waveguide design?

Benefits: (1) More energy efficient acceleration and energy stability: Less impedance due to fewer cavities (fewer surfaces to dissipate power within the waveguide). Also no unused microwave power. (2) Shorter length necessary Cons: (1) Maximum dose rate reduced by 20%

According to ABRPhysicsHelp, What collimators are used in proton therapy in a way analogous to cerrobend blocks used for electron therapy?

Brass Collimators - patient specific and define a single field.

What is the typical prescription dose for treating Rectum cancer with conventional radiation techniques (IMRT or 3DCRT)?

CCCN & Geisinger - External Beam Primary + boost: 45 Gy in 25 fxs + 5.4 Gy in 3 fractions.

What is the typical prescription dose for treating Anal cancer with conventional radiation techniques (IMRT or 3DCRT)?

CCCN & Geisinger - External Beam with SIB: 45 Gy to elective nodes, 50.4 Gy to involved nodes, and 54 Gy to primary gross tumor in 30 fractions.

What are typical prescription doses for treating bladder cancer with 3DCRT/IMRT techniques?

CCCN - Salvage Bladder 3DCRT/IMRT with boost: 42 Gy in 21 fxs to whole pelvis + 20 Gy in 10 fxs for a total of 60Gy to bladder. Bladder Bed IMRT: 50.4Gy in 28 fxs to bladder bed and pelvic lymph nodes.

What is the typical prescription dose for treating Head and Neck cancer with conventional radiation techniques (IMRT or 3DCRT)?

CCCN - Primary growth + nodes VMAT: 35 fractions to 70 Gy with SIB of 63/56 Gy. Base of Tongue VMAT : 28 fractions to 56 Gy.

What is the typical prescription dose for treating Prostate cancer with conventional radiation techniques (IMRT or 3DCRT)? SBRT? Brachy

CCCN - Prostate Bed VMAT: 70.2 to 81 Gy in 39 to 45 fractions Prostate + SV VMAT: 70 Gy SIB (56Gy/50.4Gy) in 28 fractions Prostate + Pelvis VMAT: 45 Gy in 25 fractions for pelvis lymph nodes + boost of 32.4 Gy in 18 fraction for prostate. LDR Prostate Seeds monotherapy: I-125 to 160 Gy or Pd-103 to 124 Gy Pelvis VMAT + LDR Prostate Seeds Boost: 45 Gy in 25 fractions to Pelvis + boost implant to 107 Gy with I-125 or to 95 Gy with Pd-103. Geisinger & ABRPhysicsHelp - SBRT VMAT: 5 x 7.25 Gy to 36.25 Gy LDR Prostate Seeds monotherapy: I-125 to 145 Gy, Pd-103 to 125 Gy, or Cs-131 to 110 Gy Krauss Paper - HDR Brachy monotherapy: Ir-192 to 21 Gy in 2 fractions, fractions about two weeks apart. Pelvis VMAT + HDR Brachy boost: 45 to 50 Gy in 25 fractions + Ir-192 HDR to 15 Gy in a single fraction.

What is the typical prescription dose for treating Esophageal cancer with conventional radiation techniques (IMRT or 3DCRT)?

CCCN/Geisinger - VMAT + optional VMAT boost: 45 Gy in 25 fractions + 5.4 Gy to 9 Gy in 3 to 5 fractions for a total of 50.4 Gy to 54 Gy. ABRPhysicsHelp- 3DCRT Off-cord fields + 3DCRT boost: 36 Gy in 20 fractions + boost of 28.8 Gy in 16 fractions for a total dose of 64.8 Gy.

According to ABRPhysicsHelp, Is I-131 ablation therapy an inpatient or outpatient procedure? Name any pertinent resources and elaborate as necessary.

Can be either, but to be an outpatient procedure, needs to meet one of three criteria at time of patient release provided in NUREG-1556 Volume 9. (1) patient activity is less than 33 mCi. (2) dose rate one meter from patient less than 0.07 mSv/hr. (3) patient instructed on minimizing exposure to others and dose calc performed demonstrating exposure to others less than 5 mSv.

According to residency materials, how are T2-weighted MRIs useful for in the context of radiotherapy?

Can identify edema that may want to be know for radiotherapy purposes.

According to ABRPhysicsHelp, what is the typical construction/design of energy degraders used for particle beam therapy? What is its primary purpose and safety concern that derives from its use? Where is it usually located relative to a particle beam line in the context of a medical particle accelerator?

Carbon wheel of variable thicknesses - "modulator wheel"; Meant to decrease energy of the beam to MAXIMUM target depth; they are known to produce a lot of neutron contamination; usually right before the beam line but after the accelerator.

According to ABRPhysicsHelp and MPPG.9A, what are the types of machine/program checks that should be done daily and that are unique to Cyberknife, relative to Linac-based SRS/SBRT programs? Tolerances?

Chiefly, "Auto QA" (AQA) test = robot pointing test -> the centering of a radiographic shadow of a 2cm diameter tungsten ball hidden in a cubic phantom is measured on a pair of orthogonal films.

What are typical SRS/SRT treatment prescriptions for Cranial and Spinal Arteriovenous Malformations (AVMs)?

Cleveland Clinic Treatment Scheme document - Residency Resource: 20 Gy in 2 fractions.

What are typical prescription doses for treating Cholangiocarcinoma (bile duct), Adrenal, and renal cancers with SBRT techniques?

Cleveland Clinic Treatment Scheme document - Residency Resource: Cholangiocarcinoma -> 45 Gy in 3 fractions Adrenal/Renal -> 32 Gy in 4 fractions to 45 Gy in 3 fractions

What is the typical prescription dose for treating pancreatic cancer with conventional treatment techniques (IMRT and 3DCRT) and SBRT radiation techniques?

Cleveland Clinic Treatment Scheme document - Residency Resource: 33 Gy in 5 fractions or 25 Gy in 1 fraction (Cyberknife) CCCN/Geisinger - 50.4 Gy in 28 fxs

According to ABRPhysicsHelp, what is the basic construction of a Klystron? What is the basic operation theory of the Klystron in a C-arm Linac?

Comprised of a electron filament or "gun", emitting electrons according to the PFN input, at the end of a waveguide where RF driver microwaves enter. In the Buncher Cavity of the waveguide, the oscillating electric field of the microwave accelerates each electron in accordance to their velocities, accelerating (slowing, speeding, or enacting no change) each of them such they will eventually reach a velocity corresponding to the the ~ 3 GHz frequency of the entrant microwaves. In within the cavities within the Drift Tube region of the waveguide, the accelerated electrons are allowed to "bunch" (or focus the grouping of electrons in space) by letting each of them reach the velocity corresponding to the ~3 GHz frequency The Catcher Cavity at the end of waveguide is designed to resonate with the net oscillating electric fields generated by the bunch electrons such that amplified microwaves are generated and funneled out into the transport waveguide system.

According to ABRphysicsHelp, what is the main advantage of a cyclotron over a synchrotron for a proton-therapy system? How does the footprint of a cyclotron vault compare to that of a synchrotron vault?

Cyclotrons have continuous beam eliminating interplay effects between the spill structure and scanning of a beam. ("spill structure" refers to the energy bandwidth of the particles that enter circulation of the cyclotron portion of the accelerator.) Even though the cyclotron is smaller than the synchrotron, cyclotron hardware needs (the degrader) makes a cyclotron vault not much smaller than a synchrotron vault.

According to ABRPhysicsHelp, What are the typical construction materials of scattering foils in a C-arm medical Linac? What kinda of scattering system does Varian incorporate in their machines? Briefly, how does it work?

Lead or copper Varian uses a dual-scattering foil system; the system incorporates two scattering foils: The first foil scatters the beam and the second flattens it to make the beam more uniform in the coronal plane of a patient.

According to ABRPhysicsHelp, What does the "round divergence" design of the primary collimators of a C-arm medical Linac do the enhance the quality of the generated x-ray or electron beam?

Leads to "sharper than expected" fall-off at the edges of large field sizes

According to TG-50 (AAPM Report 72) and ABRPhysicsHelp, The MLC leaves are accurately tracking position and moving the leaves through a variety of mechanisms. What position tracking mechanism has been most prevalently used in manufactured systems? What moving mechanism has been most prevalently used in manufactured systems?

Linear Encoder - transducer or sensor that converts a scaled position to an analog or digital signal. Specifically, high precision potentiometers are used for MLC position tracking. linear actuators aligned to "T-bolts" serve as a popular moving mechanism

According to ABRPhysicsHelp and MPPG.9A, what are the types of machine/program checks that should be done monthly and that are unique to Tomotherapy, relative to Linac-based SRS/SBRT programs? Tolerances?

Longitudinal Beam Profile -> Not really unique to SRS/SBRT applications of Tomotherapy, but still unique compared to Linac. Analogous to Linac radial beam profile but these profiles are comprehensive in that they are generated from combination of collimation and the moving table. -> 1% of FWHM for nominal slice width.

According to ABRPhysicsHelp, if one want to reduce the contributions to dose penumbra by reducing the magnitude of transmission penumbra, what photons energies would be best for doing so? What if wanting to reduce contributions to dose penumbra due to scatter penumbra? What photon energies optimizes the reduction in transmission AND scatter penumbra?

Lower energies -- 6/10 MV better for reducing transmission penumbra. Higher energies --- such at 18/20MV better for reducing scatter penumbra. ~ 10MV

What are typical dose-volume constraints clinically acceptable for the Contralateral Breast?

D5% <= 1.9-3.0Gy (Breast Treatments - Geisinger) Dmax <= 3.0Gy (Breast Treatments - Geisinger)

According to ABRPhysicsHelp and TG-100, what are the three categories that are used to quantify "risk"? What is the term for the quantity metric used to quantify "risk" and how is it calculated?

DOS -> Detectability = How likely is something to happen Occurrence = What can happen? Severity = What are the consequences if that something were to happen? Risk Priority Number = RPN = D*O*S

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of the localization lasers? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Daily and Monthly; 2mm/1.5mm/1mm for 3DCRT/IMRT/SRS for daily, and 2mm/1mm/1mm for 3DCRT/IMRT/SRS for monthly. Daily and Monthly; 2mm for daily, 1mm for monthly

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of jaw position indicators? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Daily and Monthly; 2mm/2mm/1mm for 3DCRT/IMRT/SRS for daily, 2mm/1mm per jaw for symmetric/asymmetric positioning controls for monthly. Daily and Monthly; 2 mm per jaw for a single field for daily, 2 mm per jaw for clinical range of motion.

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of electronic (internal physical wedges and collimator shaped) wedges? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Daily, Monthly, and Annually; Daily -> functional Monthly -> 2% deviation of central axis output or WF measured for single wedge angle Annually -> 2% deviation of Off-Axis Ratios for commonly used wedge angles Daily and Monthly; Daily -> 3% deviation of central axis output or WF measured for single wedge angle. Monthly -> Same as TG-142 Annually -> Same as TG-142

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of an photon and electron beam's output constancy? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Daily, Monthly, and Annually; 3%, 2%, and 1% Daily, Monthly, and Annually, respectively. Same as TG-142

According to ABRPhysicsHelp and TG-142, what are the daily interlock/safety test recommended? What are the monthly interlock/safety tests recommended by TG-142? the Annual Tests? What are recommended interlock/safety tests and frequencies recommended in MPPG 8.a?

Daily; Door interlock beam off Door closing safety Audio/visual monitors Radiation area monitor Beam on indicator Monthly; Laser-guard (Anticollision) interlock Annually; None Same as TG-142 but daily anticollision interlock test and recommends any additional tests QMP may deem appropriate.

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of ODI (optical distance indicator)? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Daily; 2mm/2mm/2mm for 3DCRT/IMRT/SRS. Daily and Monthly; 2 mm at isocenter for daily, 2 mm over clinical range for monthly.

According to ABRPhysicsHelp and TG-59, what is the definition of HDR? What typical radioactive source, activity quantity, and treatment delivery method does TG-59 focus on?

Delivery of dose at a dose rate of 12Gy/hr or higher to a prescription point. Ir-192, 10 Ci, and delivery via afterloader unit.

According to ABRPhysicsHelp, what kind of imaging study could be needed to treat an arteriovenous malformation (AVM)? Elaborate on this imaging study within a couple of sentences.

Digital Subtraction Angiography (DSA) - fluoroscopy technique used in interventional radiology to distinguish blood vessels from soft tissues.

What are typical dose-volume constraints clinically acceptable for the Eyes?

Dmax < 50 Gy (Pharynx Treatment - RTOG 0615) ***Dmean < 35 Gy (Pharynx Treatment - RTOG 0225)***

What are typical dose-volume constraints clinically acceptable for the Vaginal Mucosa?

Dmax <= 130 Gy (HDR Gynaecology [GYN] Treatments - Geisinger)

What are typical dose-volume constraints clinically acceptable for the Lips?

Dmax <= 45 Gy (Oral Cavity Treatments - Geisinger) ***Dmax <= 25 Gy (Head & Neck Treatments - Geisinger)***

What are typical dose-volume constraints clinically acceptable for the Lenses?

Dmax <=7 Gy (If Meningioma case - Geisinger) Dmax < 25 Gy (Pharynx Treatments - RTOG 0615)

What are typical dose-volume constraints clinically acceptable for the Ears?

Dmean < 50 Gy (Pharynx Treatment - RTOG 0225)

According to ABRPhysicsHelp summary of TG-76, what are "dose blurring effects" and "interplay effects" in the context of respiratory motion management? Describe each effect within a few sentences.

Dose Blurring effects manifest mostly in the delivery of static fields. The dose distribution determined for a target at the time of planning ends of up being dispersed across the target and surrounding tissues according to the targets motion. If looking a dose profiles, a planned centralized-high dose region would then appear to have been smooshed laterally, resulting in wider low-dose profile. Interplay effects manifest mostly in the delivery of dynamic fields (IMRT/VMAT) and scanned particle beams. The resulting discrepancies between the planned and delivered dose distributions depends on MLC positions (particle beam position) over time and tumor motion over time. Any correlation between the two timelines is usually transient.

According to ABRPhysicsHelp, what was the primary reason Co-60 machines were designed with an SAD of 80cm?

Dose rate limitations

According to Krauss, when were the first HDR prostate treatments administered? What is the typical radioactive source used for prostate HDR treatments? What is the method of administration (answer within a couple of sentences)? What factors or characteristics of a patient's case render the patient an appropriate candidate for HDR prostate brachytherapy?

During the 1990s. Ir-192. Transperineal, interstitial needle implant with transrectal ultrasound imaging guidance. The source is guided thorough the catheters of the implant via an afterloader unit. Pretty much things that are a concern for LDR treatments: (1) Prostate Size -> should be between 20-60cc, though not a hard-n-fast rule. (2) Patient positioning must allow for adequate avoidance of urethra. (3)Adequate Prostate and Rectum spacing. (4) Adequate pubic arch width to avoid interference with needle placement. (5) Minimal risk posed by anesthesia and comorbidities. (6) clear of uropathy (blockage of urinary tract)

According to ABRPhysicsHelp, where does the Circulator of a C-arm Linac direct reflected power?

Either to a water load (dissipates at heat) or circles it back into the waveguide transport system leading to the Accelerator Waveguide (which prevents wasted microwave energy).

According to ABRPhysicsHelp, What are the three ways beam energy selection can be performed? Which of the methods is most frequently used and why?

Electron Gun Current (Beam Loading): the more electrons injected into the guide, the less energy they will gain (only so much microwave power). Technique not used frequently. RF Output Power: Adjusting RF power output from Klystron or RF Driver Guide Shorting - shorting out part of the accelerating guide: The electric fields generated in the cavities of the guide are shorted to lower acceleration power, effectively making "drift tube" regions. Guide Shorting is the most frequently used since in allows for a much wider energy selection.

According to TG-50 (AAPM Report 72), There are three possible MLC-inclusive, radiation blocking configurations established by vendors of conventional Linacs. the Upper Jaw Replacement configuration is one of them. Which vendor established this configuration? Briefly describe the configuration. What are the advantages and disadvantages of this configuration?

Elekta MLCs replace upper jaws of the secondary collimators (the "y-jaws"; jaws move along axis parallel to gantry rotation axis). There is a back-up upper jaw in place just in case the MLCs fail and to help reduce leakage. Advantages: (1) Range of movement necessary for blocking adjustments small (since further up in beam path) (2) More compact treatment head (leaves do not have to be that long). (3) small leaf width. Disadvantages: (2) Positioning errors have greater impact (since further up in beam path) (3) Penumbra not as sharp (since further up the beam path)

According to ABRPhysicsHelp, what is the Klystron of a conventional-C arm Linac? Where does it approximately sit relative to the treatment room or Linac itself?

Essentially a mini-linac that serves the purpose of amplifying the microwaves from the RF driver to ~5-10 MW. It is under vacuum. It is located in the Linac stand further away from the treatment room wall, more towards the center of the treatment room, in relation to the Pulse Modulator

According to ABRPhysicsHelp and TG-100, What are "events"? What are "near events"?

Events: a failure itself and its propagation through an overall process process. Near Event: a detected failure which would have propagated through the process and resulted in detriment to quality of an overall service to a patient.

According to ABRPhysicsHelp and TG-40, what is the recommended frequency for inspecting the calibration of a barometer system? What is the recommended tolerance?

Every 3 months; 1 mmHg

According to ABRPhysicsHelp and TG-40, what is the recommended frequency for inspecting the calibration of a TLD dosimetry system used for reference dosimetry? What is the recommended tolerance?

Every Use; there is no recommended tolerance since dependent on manufacturing.

According to ABRPhysicsHelp and TG-40, what is the recommended frequency for inspecting the reading leakage of an ion chamber used for reference dosimetry? What is the recommended tolerance?

Every use; 0.1%

According to ABRPhysicsHelp and TG-40, what is the recommended frequency for inspecting the processor uniformity of film dosimetry system used for reference dosimetry? What is the recommended tolerance?

Every use; there is no recommended tolerance since dependent on film manufacturing, but should be documented.

According to ABRPhysicsHelp and TG-100, What is the the process called that identifies failure modes and then attempts to establish an assessment of risk posed by all failure modes through a risk priority number (RPN)?

Failure Modes and Effects Analysis - FMEA

According to ABRPhysicsHelp and TG-100, how are "causes", "detectablity", and "severity" associated with a failure mode and the risk priority parameters identified?

Fault Tree Analysis

According to ABRPhysicsHelp, what is the basic design of the Mammosite ABPI applicator? What are advantages of or important implications when using this applicator when considering others available commercially?

Features a balloon that is filled with saline via a syringe. Original design had is a single central catheter that travels down the center of the balloon, but now multi-lumen designs are available allowing up to three surrounding catheters (4 in catheters in total). (1)The balloon can be filled with contrast for visualization. (2) cavity is filled with saline, which improves accuracy of TG-43 calcs.

According to ABRPhysicsHelp, what is the basic design of the SAVI ABPI applicator? What are advantages of or important implications when using this applicator when considering others available commercially?

Features struts that can be expanded after implantation into cavity. This applicator does not feature a balloon. (1) strutted catheters allow for greatest degree of optimization, which is useful when optimizing does to skin and ribs. (2) There is no saline filled balloon, which which reduces the accuracy of dose calculations that employ TG-43 methodology without heterogeneity corrections.

According to ABRPhysicsHelp and TG-40, what is the recommended frequency for inspecting the calibration (dose response) of film dosimetry system used for reference dosimetry? What is the recommended tolerance?

For each batch; there is no recommended tolerance, since dependent on film manufacturing, but should be documented.

What is the gap formula for two "matched" spinal fields of a cranio-spinal treatment? How would one match the divergence of the the two cranial fields?

G = G_1 + G_2 = (d/2)*[(L_1/SSD_1) + (L_2/SSD_2)]

According to TG-50 (AAPM Report 72), There are three possible MLC-inclusive, radiation blocking configurations established by vendors of conventional Linacs. the Lower Jaw Replacement configuration is one of them. Which vendor established this configuration? Briefly describe the configuration. What are the advantages and disadvantages of this configuration?

GE (General Electric) - Siemens MLCs replace lower jaws of the secondary collimators (the "x-jaws"; jaws that move along axis perpendicular to gantry rotation axis) Advantages: (1) More compact treatment head (leaves do not have to be that long). Advantages/Disadvantage: (1) seemed most balance compared to other configurations --- in terms of Penumbra, positioning error magnification, leaf width and length, range of necessary motion. Disadvantages: None that are clear

What are typical 3DCRT and VMAT/IMRT treatment prescriptions for Brain lesions?

Geisinger & ABRPhysicsHelp- WB 3DCRT opposed laterals: 20 Gy to 30 Gy in 10 fractions. Partial Brain VMAT + optional VMAT boost: 54Gy to 60 Gy in 30 fractions + optional boost of 6 Gy in 3 fractions. Total dose usually 60 to 66 Gy. CCCN - WB 3DCRT opposed laterals: 30Gy to 35 Gy in 10 and 14 fractions, respectively. Partial Brain VMAT + optional VMAT boost: 46 Gy to 60 Gy in 23 to 30 fractions, respectively, + boost of 14 Gy to 6 Gy. total dose usually 60 to 66 Gy.

According to ABRPhysicsHelp and own experience, what are the typical fractionation schemes for Total Body Irradiation (TBI) treatments?

Geisinger - 7.5 Gy in 150cGyx5fxs to 12 Gy in 200cGyx6fxs, given twice a day, given twice a day, separated by 6 hours. ABRPhysicsHelp - 14 Gy in 350cGyx4fxs to 12 Gy in 150cGyx8fxs, given twice a day, separated by 6 hours

What is the typical prescription dose for treating breast cases with conventional radiation techniques (IMRT or 3DCRT)? Brachy?

Geisinger - Hypofractionated 3DCRT + electron/3DCRT boost: 40.05 Gy in 15 fractions + 10 Gy boost in 5 fractions. Standard Fractionated 3DCRT + optional electron/3DCRT boost: 50 Gy in 25 fractions + optional boost of 10 to 14 Gy in 5 to 7 fractions (varied widely). CCCN - Hypofractionated 3DCRT + electron/3DCRT boost: 40.05 to 42.56 Gy in 15 to 16 fractions + 10 Gy boost in 4 to 5 fractions. Standard Fractionated 3DCRT/VMAT + optional electron/3DCRT boost: 50 Gy to 50.4 Gy in 25 to 28 fractions + optional boost of 10 Gy to 14 Gy in 5 to 7 fractions. HDR Brachy APBI: 34 Gy in 10 fractions, twice a day via SAVI/Contura applicator. 3DCRT APBI: 34 Gy in 10 fractions, 1 fraction per day.

According to ABRPhysicsHelp, when fiducial markers are implanted for IGRT purposes, what is the typical material used? Why? For what kind of treatment cases are fiducials normally used? How are they normally implanted?

Gold. Several Reasons: (1) non-reactivity (2) Good high image contrast. (3) clearly distinct from any surgical clips that may be proximally placed. Large needle with local anesthesia by a specialist such as urologist or radiation oncologist. Pelvis cases (prostate at CCCN but).

According to ABRPhysicsHelp, When referring to a dose to be administered by proton therapy, what is the unit of RBE corrected dose?

GyRBE

According to ABRPhysicsHelp, How does Varian adjust beam energy in their C-arm medical Linacs (Recall the three general methods of energy selection in Linacs)?

Highest energy (18/20 MeV) requires the entire waveguide Lowest energy (6 MeV) shorts the waveguide by a copper pin Subtle variations in between short the waveguide and vary RF driver output

What is the typical treatment regiment and technique for eye plague treatments for which Ocular Melanoma is the typical disease?

I-125 seeds in eye plaques with gold backing. Deliver 8500 cGy in 96 hours (4 days).

According to ABRPhysicsHelp, kilovoltage electrode tubes once upon a time used for therapy and now more often used for imaging were designed with a target (anode) that was "beveled"? What is the purpose of this "bevel" design of the anode? What is side-effect of this bevel design? What is the buzz word for this side-effect?

Increase the surface area electrons incoming from the cathode can strike the target while the focal spot of the electron stream remains effectively small. "Heel effect" - energy hardening of the photon beam towards the lower-bevel edge of the anode due to photons generated deeper in the target.

According to ABRPhysicsHelp and TG-40, what is the recommended frequency for inspecting the extra-cameral signal (stem effect) of an ion chamber used for reference dosimetry? What is the recommended tolerance?

Initially or after repair; 0.5%

According to ABRPhysicsHelp and TG-40, what is the recommended frequency for inspecting the recombination of an ion chamber used for reference dosimetry? What is the recommended tolerance?

Initially or after repair; there is no recommended tolerance, since dependent on chamber model and irradiation conditions.

According to ABRPhysicsHelp and TG-40, what is the recommended frequency for inspecting the calibration of a thermometer system? What is the recommended tolerance?

Initially; 0.1 degrees

According to ABRPhysicsHelp and TG-40, what is the recommended frequency for inspecting the energy dependence of a Diode dosimetry system used for reference dosimetry? What is the recommended tolerance?

Initially; there is no recommended tolerance since dependent on manufacturing.

According to ABRPhysicsHelp and TG-40, what is the recommended frequency for inspecting the extra-cameral signal (stem effect) of a Diode dosimetry system used for reference dosimetry? What is the recommended tolerance?

Initially; there is no recommended tolerance since dependent on manufacturing.

According to ABRPhysicsHelp and TG-40, what is the recommended frequency for inspecting the linearity of a TLD dosimetry system used for reference dosimetry? What is the recommended tolerance?

Initially; there is no recommended tolerance since dependent on manufacturing.

According to ABRPhysicsHelp and TG-40, what is the recommended frequency for inspecting the linearity of a Diode dosimetry system used for reference dosimetry? What is the recommended tolerance?

Initially; there is no recommended tolerance since dependent on manufacturing.

According to ABRPhysicsHelp, what is operating principle of pulsed-dose rate (PDR) brachytherapy? What was the motivations for this treatment modality? What were some of the concerns associated with this treatment modality?

Inserting an HDR source into patient for a matter of seconds to minutes, over 24 hours. (1) To make HDR treatments resemble that of LDR treatments in radiobiological terms ->It was popular when HDR use was new, hence little clinical data on HDR. (2) Make physicians more comfortable with using HDR sources and afterloaders -> patients stay and care similar to LDR. (1) Increase of error risk -> really a consequence of having so many HDR treatments in uncontrolled/unspecialized area, carried out by unspecialized staff (staff not trained in radiation therapy treatments).

According to ABRPhysicsHelp, what treatment technique is enabled by outfitting a proton therapy system with an active scattering (scanning) system? What else would the proton therapy system need to make this treatment technique possible?

Intensity Modulated Proton Therapy (IMPT); a synchrotron to actively adjust proton energy and hence penetration depth.

According to ABRPhysicsHelp, What is the main advantage of pursing other heavy ions for radiation therapy other than protons? Summarize in one sentence. In another sentence, why is this the case?What other heavy ions are currently being investigated for therapeutic use?

Ions heavier than protons have Bragg Peaks with shaper dose fall-off and greater biological effectiveness (RBE ~ 2 to 5) at equivalent energies. Greater mass means less range/energy straggling. Helium and Carbon

According to ABRPhysicsHelp, what is the Modulator (Pulsed Modulator) of a conventional-C arm Linac? Where does it approximately sit relative to the treatment room or Linac itself?

Is acts as a big power supply that supplies power to all components of a Linac. It features two subsystems: the Thyratron and the Pulse Forming Network (PFN) It sits in the stand of a Linac, against or within the treatment room wall.

According to ABRPhysicsHelp, what is the definition of the "phase II" of a clinical trial? Describe within a couple of sentences, as necessary.

Is the state of a clinical trial during which studies are performed to ascertain if a treatment is EFFECTIVE WITHOUT EXCESSIVE SIDE-EFFECTS. The study cohort consists of a moderate number of people, such as 25 to 100 people.

According to ABRPhysicsHelp, what is the definition of the "phase I" of a clinical trial? Describe within a couple of sentences, as necessary.

Is the state of a clinical trial during which studies are performed to ascertain if a treatment is SAFE. The study cohort consists of a small number of people, such as a dozen.

What is the basic purpose of a synchrotron injector? What system shares the same the operating and design principle as the synchrotron injector?

It accelerates a low stream of particles to a certain energy before the particles enter the circular accelerating cavity. works like a linear accelerator.

According to ABRPhysicsHelp, what are the basic components of a particle beam line that is established for the particles exiting a medical accelerator? Describe in a single sentence.

It consists of bending magnets under vacuum.

According to ABRPhysicsHelp, what are the basic components of the Accelerator Electron Gun of a conventional-C arm Linac? What are the functions of the each of the components?

It features a triode (cathode, anode, grid), focusing electrodes, and collimator. Cathode - made of Tungsten doped with Barium Oxide (BaO). It acts as an electron source by boiling off electrons. Anode - positive charged, doughnut shaped electrode that accelerates the electrons towards the accelerator waveguide. Grid - a wire mesh capable of emitting a varied electric field within a region of space to adjust the amount of electrons amassing in each of the electron pulses (or "bunches") that formed PFN-driven emissions of the electrons from the Cathode. This component controls the final dose rate. Focusing Electrodes and Collimator - narrows the electron pulses into a narrow pencil beam cross-section

According to ABRPhysicsHelp, what is the Waveguide Transport System of a conventional-C arm Linac? Where does it approximately sit relative to the treatment room or Linac itself?

It is a network of rectangular cross-sectioned, metal tubes used to transport the Klystron microwave power to the Accelerator Waveguide. The system is still in the stand of the Linac

According to ABRPhysicsHelp, what is the Accelerating Waveguide of a conventional-C arm Linac? Where does it approximately sit relative to the treatment room or Linac itself?

It is a standing wave design, waveguide meant to accelerate the electron pulses from the gun to greater energies (to the MeV range). The Klystron microwaves resonate in the waveguide forming a standing wave. The cavities and the magnetic fields of the microwaves create strong electrical fields in the cavities further bunch and accelerate the electrons in the bending magnet. It is located above the stand, closer to the treatment room wall relative to the Linac treatment head.

According to ABRPhysicsHelp, what is the "Interplay Effect" in the context of photon beam delivery? Describe in a single sentence.

It is a term that refers to dose discrepancies that occur in MRT plan delivery during which MLC motion is occurring simultaneously as target motion.

According to ABRPhysicsHelp, what is the "Interplay Effect" in the context of proton beam delivery? Describe in a single sentence.

It is a term that refers to the dose discrepancies that manifest in scanning proton plans during which there is the incoordination of target motion and the beam delivery timeline.

According to ABRPhysicsHelp and your own experience, Describe the basic operating principles and mechanical design of the Tomotherapy modality. Summarize your description with a few sentences.

It is an Accuray owned radiation therapy modality that utilizes a magnetron powered Linac housed in a CT-unit design. It uses a 6MV-FFF beam fixed at 850cGy/min and binary MLC field shaping to deliver dose in either a helical fashion --- the gantry ring rotates the source and modulating MLCs while the patient is being translated into the bore --- or "guitar-hero" action --- gantry ring remains at set of fixed positions as MLCs modulate during the translating of the patient through the bore. It features patient localization and patient tumor tracking/respiratory motion management system ("Synchrony") powered individually or through the combination of MC-CTs, infrared monitoring, and landmark (fiducial and bony landmark) tracking.

According to ABRPhysicsHelp, Describe the basic operating principles and mechanical design of the MRI-Guided treatment modality. Summarize your description with a few sentences. What are the two most prominent ones on the market right now?

It is an emerging treatment modality that combines a MRI scanner into either a Co-60 teletherapy unit or a Linac. The motivation of this modality is that MRI offers enhanced soft-tissue contrast and allows for the possibilities of adaptive radiotherapy taking into account intra-fraction motion and changes. MRidian by Viewray -> 0.35T, 6-FFF beam. Unity by Elekta -> 1.5 T, 7-FFF

According to ABRPhysicsHelp, what is the "Electron Return Effect" in the context of MRI-Guided radiation therapy? Describe within a couple sentences as necessary. How can this effect be minimized (or maximized) for a given patient? where along the primary radiation beam path is this effect is of particular concern?

It is an phenomenon that occurs in a phantom or patient due to the acceleration of secondary electrons generated in the phantom by the MRI magnetic field. It specifically refers to secondary electrons that are accelerated enough to curve into a path wrapping back upstream. (1) Reducing field strength (2) Having patient surface as normal to beam propagation as possible. (3) limit heterogeneities present along primary beam path. Tissue-air interfaces -> can cause addition of "re-entrant" dose at interfaces.

According to ABRPhysicsHelp and TG-179, Compared to the other IGRT systems and other than superior image quality, what is an irrefutable advantage of the kVCT-on-rails?

It is ideal for adaptive radiotherapy.

According to AAPM TG-222 and you own experience, What is permanent mesh Brachytherapy? Summarized the essence of it within a couple of sentences. What anatomical sites have found this type of brachytherapy useful? What radioisotopes are commonly used when employing this technique? What are the clinical indications for such a therapeutic technique? List them and elaborate upon each within a couple sentences as necessary.

It is the treatment of irregular shaped volumes using an array of "dot" geometry radioactive seeds. The array is constructed by weaving in evenly spaced seeds (stranded seeds) into premade strands of some bio-absorbable material. Lung, pelvis, H&N, Spine, Breast, Brain, and various thoracic locations. Same as LDR prostates: I-125, Pd-103, and Cs-131. - Irregular volumes -> volume that treating brachytherapy through the use of needles or catheters would fail to deliver uniform doses; curved anatomy. - Superficial targets -> targets that do not extend too deep, or at least treatable using radioisotopes at disposal yet still capable of giving conformal doses.

According to ABRPhysicsHelp, what is the process of "beam steering" a photon beam for a conventional Linac?

It refers to the adjustment of positioning of the electron beam via the linac bending magnets in the treatment head so that photon beam generated at the target is translated across the flattening filter until centered.

According to ABRPhysicsHelp, what is prostate hormonal therapy? How could it be pertinent to radiation treatments a patient may receive?

It refers to therapeutic techniques that work to stop the production androgens (male sex hormones) and their ability to reach cancer cells. it kills cancer cells and decreases the growth rate of cancer cells in the prostate, which could shrink the prostate. Really, just need to consider the potential change in size of the prostate and its timing if considering radiation therapy treatments.

According to ABRPhysicsHelp and TG-59, what are the notable advantages of HDR brachytherapy in comparison to LDR brachytherapy? Disadvantages? List them and elaborate upon each as necessary. Only include advantages and disadvantages that are pertinent to modern day HDR treatments.

Advantages (1) Increase dose optimization (2) Outpatient treatment (3) Smaller applicators, hence less patient discomfort (e.g., gynecological tandems -> HDR = 3mm diameter while LDR = 7mm diameter). (4) Better documentation for treatment - utilization of automatic documentation from the HDR unit versus relying on the diligence of person inserting the sources to document the treatment. (5) Reduction of exposure to health care providers. Disadvantages (1) Increase risk of catastrophic failure - due to high doses being delivered within short time. (2) Increased importance in accurate dosimetry and anatomic information. (3) In the event of malfunction of unit and source being unretractable, an increased danger of exposure for health care providers. (4) Increase complexity of treatments -> due to the need of safety interlocks and monitors when administering treatment and, thereby, more training.

According to ABRPhysicsHelp, What are the two typical pieces of hardware that are be inserted into the "snout hold" of a "nozzle" of a particle beam therapy system?

An aperture and/or a range compensator - essentially patient specific devices.

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of electron MU linearity? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Annually; +- 2% for delivered MU >= 5 Annually; +- for delivered MU in reasonable clinical range.

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of photon MU linearity? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Annually; +- 2% for delivered MU >= 5, +-5% for delivered MU< 5 Annually; +- 2% for delivered MU >= 10

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of radiation isocentricity (MLC/jaw radiation isocenter with collimator, gantry, and couch rotation)? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Annually; +-2mm radius for 3DCRT/IMRT from baseline but +-1 mm radius walkout from baseline for SRS. Annually or more frequency if SRS/SBRT program; +- 1 mm radius walkout

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of photon and electron output vs gantry angle? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Annually; 1% from baseline Annually; 1% from output at IEC gantry 0 degrees

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of photon and electron OAF vs gantry angle? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Annually; 1% from baseline -- ONLY SPECIFIED FOR ELECTRONS Annually; 2% of OAFs at IEC gantry 0 degrees

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of an photon beam's energy constancy (beam quality)? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Annually; 1% from baseline PDD/TPR Monthly and Annually; 1% change in value from PDD/TPR for monthly and annually

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of Arc mode (expected MU and degrees for arc trajectory)? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a? Elaborate upon this test a bit

Annually; 1% from baseline, but 2% of MU and 1 degree for SRS Arc mode. Annually; 2% of MU and 2 degrees A test if dynamic (VMAT) deliveries not used, but something analogous to 3D conformal arc therapy is used.

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection special procedure modes (TBI/TSET PDDs/TMRs, OAFs, and outputs with and/or without accessories)? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Annually; 1% or 1mm discrepancy for PDDs/TMRs and OAFs, 2% from baseline for outputs with and without accessories. Annually; same as TG-142 except 2% from baseline for OAFs (profile constancy).

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of Table top sag? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Annually; 2 mm from baseline This test is not recommended in MPPG 8.a.

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of field size dependent output factors for photons? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Annually; 2% for sizes less than 4x4cm^2 but, 1% for sizes greater than 4x4cm^2 This test is not recommended in MPPG 8.a.

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of output factors for electron applicators? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Annually; 2% from baseline This test is not recommended in MPPG 8.a..

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of Electron applicator collimator settings/physical inspection/interlocks? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Annually; functional Same as TG-142

According to ABRPhysicsHelp and TG-40, what is the recommended frequency for inspecting the densitometer linearity of film dosimetry system used for reference dosimetry? What is the recommended tolerance?

Annually; there is no recommended tolerance, since dependent on film manufacturing, but should be documented.

According to ABRPhysicsHelp summary of TG-76, what are Real Time Tumor Tracking (RTT) techniques in the context of respiratory motion management? Describe their fundamental principle and typical applications of such techniques within few sentences.

Any technique that directly monitors tumor movement during treatment. Such systems often use a combination of fiducial markers implanted in a tumor, external markers for respiratory cycle tracings, and live treatment imaging to monitor and account for tumor motion. Cyberknife Synchrony system is an example of respiratory RTT (while it can still do RTT for non-respiratory cases, but those other techniques are not called "Synchrony"); Tomotherapy Synchrony system is another example (its "Synchrony" system includes respiratory and non-respiratory induced motion).

According to ABRPhysicsHelp Summary of TG-101, what sites are usually treated with SBRT? What is a reasonable size limit for targets treated with SBRT?

Lung, Liver, and spine lesions. less than 5cm-7cm.

According to ABRPhysicsHelp, What is the key functional difference between a Magnetron and a Klystron?

Magnetron acts as a source of microwave power; Klystron acts as a amplifier of microwave power (hence needs to be couples with a RF Driver).

According to ABRPhysicsHelp, what are Accelerated Partial Breast Irradiation (APBI) brachytherapy applicators commercially available? Just list them in ascending order of first date of FDA approved use in clinic.

Mammosite Contura SAVI

According to ABRPhysicsHelp and TG-137, what does "MPD" stand for? what about "mPD"? What does each of these acronyms describe/represent?

Matched Peripheral Dose -> dose delivered to a volume equal to the prostate volume. (so equivalently, D100?) minimum Peripheral Dose -> the lowest dose at the intersection of the periphery of each seed array and a plane halfway between the planes carrying the seed. (sounds like contraction ROI for evaluating the "target" relative to most peripheral seeds).

According to AAPM Online Learning Center Lecture, What are the two possible methods of range compensation techniques employed in the "nozzle" of a particle beam? What is the hardware used for each of these techniques? Regardless of the technique, what is the effect of these range variation techniques?

Modulation wheel and continuous synchrotron energy variation. Modulation wheel -> wheel with thickness gradient along the circumference of the wheel. Synchrotron Energy Variation -> need a synchrotron accelerator. Creates a SOBP.

According to ABRPhysicsHelp, What are the components of a passive scattering system in a particle therapy system that utilizes modulator wheels? List them in the order of most upstream to most downstream.

Modulator Wheels-> Scatters->Collimation->Compensator

According to ABRPhysicsHelp and TG-142, what are the recommended monthly respiratory gating tests to be performed during linac QA. Annual tests? What are the recommended frequencies and tolerances of each test?

Monthly and Annually; Monthly -> -Beam output constancy -> 2% -Phase, amplitude beam control -> functional -In-room respiratory monitoring system -> functional -Gating interlock -> Functional Annually -> -Beam energy constancy -> 2% -"Gate-on" temporal accuracy of phase/amplitude -> 100 ms of expected -Calibration of surrogate for respiratory phase/amplitude -> 100 ms of expected

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of treatment couch position indicators for translation and rotations? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Monthly and Annually; 2mm/1 degree for 3DCRT/IMRT and 1mm/0.5 degree for SRS for Monthly. 2mm/1 degree over "full range of motion" for Annual. Monthly; 1mm/0.5 degree for relative movements 2mm/1 degree for table position to isocenter

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of an photon beam's flatness and symmetry (beam profile constancy)? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Monthly and Annually; 1% from baseline for monthly and annually Monthly and Annually; 2% from baseline for monthly and annually

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of photon dose rate constancy (photon output vs dose rate)? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Monthly and Annually; 2% from baseline for typical dose rate for monthly, 2% from baseline for all used dose rates. Annually; 2% from baseline for all used dose rates.

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of an electron beam's energy constancy (beam quality)? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Monthly and Annually;+- 2%/2mm from expected percent depth dose/expected depth for monthly, and +- 1 mm from expected depth. Monthly and Annually; +- 2mm from expected depth (such as 50% with 2mm of R50.)

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of Gantry/Collimator angle indicators? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Monthly; 1 degree for digital indicators Monthly; 1 degree

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of Cross-Hair Centering (graticule walkout)? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Monthly; 1 mm Same as TG-142

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of MLC position accuracy? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Monthly; 1 mm at cardinal angles (picket fence). Same as TG-142

According to ABRPhysicsHelp and TG-40, what is the recommended frequency for inspecting the calibration of a Diode dosimetry system used for reference dosimetry? What is the recommended tolerance?

Monthly; 2%

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of light-to-radiation field coincidence? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Monthly; 2mm or 1% on a side (jaw) After service; 2mm per jaw (side)

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of MLC travel speed? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a?

Monthly; Assess no loss of speed greater than 5 mm/s. There is no such recommendation in MPPG 8.a.

According to Krauss, what is the key disadvantage of HDR prostate brachy treatments, especially in relation to LDR prostate treatments?

More source shielding due to higher energy radioisotopes (need treatment vault, cannot handle source directly, etc.).

According to ABRPhysicsHelp summary of TG-76, What is general directionality of most organ motion due to respiratory motion? How much motion is typically observed in a patient's axial plane?

Mostly superior/inferior direct, but this does not mean motion cannot occur within the axial plane. Typically within 2mm displacement in the axial plane.

According to ABRPhysicsHelp, in regards to the patient factors of dose delivery inaccuracies, other than accounting for target motion in proton therapy, what other motion must be account for due to the dose nature of proton beams? What is the solution for addressing motion due to target motion? What is the solution for the other phenomenon that must be accounted for?

Motion of non-target heterogeneities - density changes upstream from target as a function of time. Make an internal target volume analogous to that made in cases treated using photon therapy. Adapted range margins - use higher effective energy than deemed necessary

According to ABRPhysicsHelp Summary of TG-101, Why is the scientific motivation behind SBRT? Explain this within a few sentences. Is there a clinical benefit, compared to conventional methods, for body irradiation, to doing SBRT treatments? Explain within a few sentences.

Motivated by a number of rationale supporting its use as a curative or palliative effort. The following surmise the rationale motivating such treatements: (1)Theory of Oligometastases - if small number of mets, a cure still viable. (2) Immunomodulation - abrupt delivery of radiation can stimulate immune response against cancer. (3) Noroton-Simon Hypothesis - decreasing tumor burden below lethal level. Any clinical benefit in compared to conventional treatment is still under continuous evaluation, more so for some anatomical sites than others.

According to ABRPhysicsHelp and Khan, What kind of collimation should be employed for electron arc therapy treatments?

None, other than Linac jaws and lead blocks on patient surface to outline treatment field area.

According to ABRPhysicsHelp, How is Co-60 to be used for radiotherapy applications made?

Nuclear fusion reactions via bombardment of Co-59 with neutrons

According to ABRPhysicsHelp, what is the Thyratron of a conventional-C arm Linac? Where does it approximately sit relative to the treatment room or Linac itself?

One of the two components of the Linac Modulator. The thyratron act as a high-frequency on-and-off switch by the charging capacitors in circuits. There are two independent thyratrons in a Varian: the DQing thyratron and the main thyratron. The DQing thyratron sits before the Pulse Forming Network (PFN) and controls the charging of the PFN circuits. The main thyratron sits after the PFNs to regulate the pulses leaving the Pulse Modulator system.

According to ABRPhysicsHelp, what is the Pulse Forming Network (PFN) of a conventional-C arm Linac? Where does it approximately sit relative to the treatment room or Linac itself?

One of the two components of the the Linac Modulator. It steps up voltage input to ~ 120 kV, forms ~ 3 GHz voltage pulses, and emits them to the RF driver, klystron, and the accelerator electron gun. It sits within the linac pulse modulator in the stand of the Linac.

According to Khan, what should additional be done to "calibrate" an electron beam utilized for electron arc therapy?

One of two procedures: (1) Calculate integrated beam profiles -> requires integrating stationary electron beam profiles over fixe angular intervals to estimated accumulated dose to point at center of rotation. (2) Direct Measurement -> requires ion chamber in cylindrical polystryrene or Lucite phantom.

According to ABRPhysicsHelp, What are the two possible lateral scattering techniques employed in the the "nozzle" of a particle beam? What hardware is used for each of these techniques?

Passive Scattering and Active Scattering (or spot scanning) technique. Scatterers enable the passive scattering technique. Steering magnets enable the active scattering (or spot scanning) technique.

According to ABRPhysicsHelp summary of TG-106, what typically transpires during the commissioning of a medical linear accelerator?

Physicist performs collects beam data from the machine that would be needed for the treatment planning system utilized for patient treatments. Afterwards, would run validation tests. Validation tests and the necessary beam data sampling is dependent on the needs of the linac and judgment of the physicist.

According to ABRPhysicsHelp, What is a unique in-vivo dosimetry method that can be utilized for proton therapy? In one sentence, describe how it works. Other than in-vivo dosimetry, what more clinical uses can it offer?

Post-Treatment PET scan It detects anti-parallel gamma rays from the annihilation of positrons generated by nuclear capture interactions between the nuclei of the patient medium and the impinging protons. (1) Detect daily setup differences (2) Infer information about actual proton therapy delivery and beam range. (3) Detect anatomical changes such as heterogeneities

According to ABRPhysicsHelp, What is the basic construction and design of MU chamber of a C-arm medical Linac? How many are typically featured in such Linacs and why that many?

Pressurized, independent parallel-plate ion chambers There are normally 4 of them, so that beam symmetry and flatness can be monitor in 4 quadrants of space.

According to ABRPhysicsHelp and TG-59, what precautions and verifications should be performed prior to initial HDR brachytherapy delivery, during patient setup of a fraction delivery? List them out, and clarify briefly as necessary. What quality assurance measures should be performed after the the delivery of fraction of an HDR brachytherapy treatment? List them out, and clarify briefly as necessary.

Prior to Delivery (1) Verify Emergency Equipment is present --- leaded pig, forceps, and any cutting tools such as wire cutters (2) Verify GM or Survey meter present in good working order --- verify batteries, check correct reading with typical background, and check correct reading with check source (if available). (3) Confirm patient identity --- make sure multiple staff present, used redundant sources of identity, make sure patient gives information (do not use "yes or no" questions). (4) Verify the correct applicators are connected to correct channels --- at least two people should do this. (5) Verify dwell times and positions of plan match as presented at the console of the treatment unit. (6) Note time fraction delivery initiated --- important if delivering two fractions a day, since need to administer at least 6 hours apart. After Delivery (1) Check area monitor and GM/Survey meter to verify source retraction. (2) Note time fraction delivery complete --- important if delivering two fractions a day, since need to administer at least 6 hours apart. (3) Survey patient to confirm source returned to HDR afterloader. (4) Secure HDR unit --- lock it up.

According to ABRPhysicsHelp and TG-100, What is the endeavor of graphically representing the flow of steps that occur in a process being evaluated via a prospective safety approach?

Process Mapping

According to ABRPhysicsHelp, How does the active scattering (scanning) method pose less of a radiation exposure concern than the passive scattering method in the context of proton therapy systems?

Produces less neutron scatter.

According to ABRPhysicsHelp, other than serving as proton therapy accelerators, what other medical use do cyclotrons serve?

Production of radiopharmaceuticals F-18 (O-18 bombarded with protons).

According to ABRPhysicsHelp and TG-40, what is the recommended frequency for redundancy (reading stability) check of an ion chamber used for reference dosimetry? What is the recommended tolerance? What exactly is meant by "redundancy check"? Is this check done by your clinic, how often and how do you do it?

Quarterly (read TG-40 passage, and not table); 2% The phrase refers to the inter-comparison of your "local standard" dosimetry system to another "independent" dosimetry standard by using both to measure a "calibrated" source of radiation. Yes but we do it yearly rather than quarterly. During one day, we measure the output of a single Linac using ion chamber dosimetry systems that are are devoted to monitoring outputs of Linacs at other clinics.

According to ABRPhysicsHelp, what is another term for a "bolus" in proton therapy? What makes these "boluses" different? What does the difference account for?

Range Compensator; they are milled so depth varies through the material; the impact of patient surface irregularity and internal heterogeneities (motion, alignment error, etc.) on the distal coverage of the target volume.

According to ABRPhysicsHelp and MPPG.9A, what are the types of machine/program checks that should be done daily and that are unique to Tomotherapy, relative to Linac-based SRS/SBRT programs? Tolerances?

Red/Green Laser Congruence -> Not necessary unique to SRS/SBRT, but still unique compared to Linac -> 1 mm

According to ABRPhysicsHelp, what is the meaning of "adjuvant therapy"? What are the other two variations of adjuvant therapy? What are examples of an adjuvant therapy and the other two variations that are relevant to radiotherapy?

Refers to a secondary treatment that administered after a primary mode of treatment. Typical Example = radiation treatment that is administered after a surgery to clear microscopic disease, as in breast cancer cases. Neoadjuvant = secondary form administered BEFORE the primary mode. Typical Example = radiation treatment that is administered before surgery to reduce tumor to resectable size. Concomitant (Concurrent) = secondary form and primary form of treatment are administered at the same time. Typical example = radiation treatment that is administered at the same time as chemotherapy.

According to Wepassed!, what is meaning of "afterloading" in the context of brachytherapy radiation treatments? What is meant by "remote loading" in the context of brachytherapy treatments? What is meant by "manual loading" in the context of brachytherapy treatment?

Refers to technique that loads a radioactive material into apparatus AFTER verification of proper placement of applicators. Refers to technique that loads a radioactive material into apparatus with staff out of treatment room, or no in same room as patient. Refers to technique in which radioactive material is loaded into an apparatus physically by staff.

According to ABRPhysicsHelp and TG-100, What is the meaning of the "Severity" parameter in the context of Failure Modes and Effects Analysis (FMEA)? What is the value range of this parameter?

Reflects magnitude of impact of the failure mode if not detected and/or corrected. 1 to 10

According to ABRPhysicsHelp and TG-100, what is the meaning of the "Occurrence" parameter in the context of Failure Modes and Effects Analysis (FMEA)? What as the value range of this parameter?

Reflects probability that a specific CAUSE will result in a failure mode (Note: it is NOT the probability that a failure mode will occur, it is the probability that a failure mode occurs GIVEN A SPECIFIC CAUSE.) 1 to 10

According to ABRPhysicsHelp and TG-100, What is the meaning of the "Lack of Detectability" parameter in the context of the Failure Modes and Effects Analysis (FMEA)? What is the value range of this parameter?

Reflects probability that failure would NOT be detected. 1 to 10

According to ABRPhysicsHelp and TG-147, How do radiofrequency localization and positioning systems work? Describe in a sentence. Give a current clinical example of such a system and briefly (one to two sentences) describe how it works?

Rely on RF transmitters implanted in patient's body to relay signals to receivers beyond the patient's body. Calypso from Varian - transponders (or "beacons") which consist of an AC current are implanted, typically, in the prostate or prostatic bed under ultrasound guidance. These transponders interact with the magnetic fields produced by a source coil in an array panel positioned closely above the patient during treatment to generate a resonate signal in the transponders, which themselves generate a magnetic decay signal detected by receiver coils in the array.

According to ABRPhysicsHelp, When determining necessary shielding for an electron beam, as in the context of lip or eyelid treatments, how does one normally estimate the required shielding (using any material) for an electron beam of some nominal energy? If using lead as the shielding material for a 12 MeV electron beam, what should be the thickness of the shield? If using high density materials to shield, such as lead, what should be of concern? How does one account for this?

Shielding thickness should be the electron beam practical range in water (MeV/2 [cm]), then scaled appropriately by the ratio of shield material density to water. Lead density ~ 11 g/cc Water density ~ 1 g/cc practical range ~ 6 cm shield thickness ~ 6cm (1/11) ~ 5.46 mm Backscatter to tissue from shield. Wrap shield with approximately water equivalent material, like wax.

According to ABRPhysicsHelp and TG-179, which medical accelerator vendor, IGRT systems employ CT-on rails?

Siemens Primatom

According to ABRPhysicsHelp, what is the basic design of the Contura ABPI applicator? What are advantages of or important implications when using this applicator when considering others available commercially?

Similar to Mammosite applicator but has two key distinctions: (1) has five channels/catheters (2) Has a vacuum port to remove air and seroma around balloon (1) Better optimization possibilities because of the extra catheters in comparison to Mammosite. (2) cavity is filled with saline from balloon, which improves accuracy of TG-43 calcs.

According to ABRPhysicsHelp, how does target motion impact Multi Field Optimized (MFO) plans for proton therapy?

Since these plans use scanning (rastering) delivery technique, the "interplay effect" is much more pronounced for these plans.

What is the operational description of a standing waveguide design?

Standing Waveguide Design - creates spatially fixed yet temporally varied superposition of microwaves by their reflection back and forth within the waveguide. This standing wave creates spatially fixed yet temporally varied electric fields that are in synch with the timing of bunches electrons as to accelerate them..

According to ABRPhysicsHelp, the cavities of a klystron can be tuned independently of each other to vary the gain (the power of the output vs the input) and the frequency bandwidth of output. What happens to the gain and frequency bandwidth if the cavities' tuning is synchronous (designed to resonate at the same frequency)? What about when the cavities' tuning is staggered (designed to resonate at slightly different frequencies)?

Synchronous Tuning - Higher gain, narrow bandwidth Staggered Tuning - Lower gain, larger bandwidth.

According to ABRPhysicsHelp and TG-147, What do all nonradiographic localization and positioning systems basically achieve? What are the common buzz words for this basic process?

Take 3D-data and convert it into 2D-images. "Stereo Localization"; "Stereo Correspondence" imaging; "Stereoscopic" imaging; "Binocular" Imaging

According to ABRPhysicsHelp and TG-100, what is the basic mechanic of Fault Tree Analysis?

Takes a failure mode, the end event, and back projects links to input failure modes, the input events, via logic gates until the primary event is discovered.

According to ABRPhysicsHelp, the RF Driver frequency is adjusted in accordance to what condition of the Main Waveguide in a typical C-arm Linac? What is the system called that manages this feedback loop?

Temperature - Waveguide resonant frequency changes as the waveguide expands and contracts Automatic Frequency Control (AFC)

According to ABRPhysicsHelp and my own experience, where to do most tissue dose tolerances derive from for conventional/IMRT treatments? What about tolerances for SRS/SBRT? What are typical key limitations of prevalent tissue dose tolerances utilized clinically today? What is a typical complication rate associated with a reported tissue dose tolerance?

The "Emami" paper (conventional) and QUANTEC papers (IMRT). SRS/SBRT -> trial protocols and AAPM TG-101 report. (1) Dose tolerances are not "safe" doses -> there is a complication rate associated with any tolerance. (2) Do not take into account adjuvant or concurrent treatments, such as chemotherapy. (3) Based on calculations without heterogeneity corrections. ~5%

According to ABRPhysicsHelp and Khan, during treatment planning of electron arc therapy, what prominent phenomenon needs to be taken into account when selecting beam energy? Explain this phenomenon.

The "velocity effect". It is an observed increase in penetration depth in comparison to a stationary field due to the continuous movement of the field exposing deeper tissue points during a longer duration of the treatment than shallower points.

According to ABRPhysicsHelp and TG-179, other than the CT unit being in the same room as the linac, what is the only other distinction between kVCT-on-rails and a conventional CT simulator?

The CT gantry slides on rails to scan the patient, rather than the patient being moved through the gantry via the treatment table.

According to TG-40, What is JCAHO? What does it do? What is its specific relationship with radiation oncology clinics? What is another entity that is similar to this one and has influence on radiation oncology practices?

The Joint Commission on the Accreditation of Health Care Organizations --- an United States non-profit organization. (1) It accredits other United States health care organizations/programs (2) It sets criteria for health care organizations in documenting the quality of patient care (3) It audits health care organizations quality of patient management. Radiation Oncology clinics must fulfill their requirements and recommendations as minimum QA requirements. American College of Radiology

According to ABRPhysicsHelp, what is the primary physics challenge clinicians are faces when administering MRI-Guided radiation treatment to patients? Describe within a couple of sentences. What are other challenges/concerns that come administering such treatments? List them and elaborate upon each or how each can be addressed within a couple of sentences.

The interaction between the magnetic field produced by the MRI unit and the electron beam generated by the Linac unit; electron acceleration in magnetic field complicates a couple of treatment aspects: (1) calculations necessary for accurate dosimetry and (2) patient safety due to the "Electron Return Effect" (ERR). All other issues are due to the the presence of the MRI unit: (1) MRI is a giant magnet and will pull anything ferromagnetic into it, which is a safety issue -> establish protection zones and ensure people are screened for metallic objects upon entering the treatment room. (2) RF signals for MR can affect electronics of important devices and Linacs in adjacent rooms -> make sure enough RF shielding in MR treatment room to reduce magnetic strength below 5 Gauss (just for perspective, MRI unit field strength is on magnitude of 40,000 Gauss). (3) Dosimetry equipment and Immobilization devices need to be MR-compatible.

According to TG-50 (AAPM Report 72) and ABRPhysicsHelp, What is a "doubled focused" design of a MLC leaf? What MLC configurations utilize this design?

The leaves are designed to reduce unnecessary beam attenuation by being shaped to match the beam divergence occurring in the planes perpendicular and parallel to the leaf motion (along the width, height of the leaf, and length of the leaf). Leaf ends are straight but the entirety of each leaf are curved to create the focus effect. Siemen's Lower Jaw configuration utlizes this design.

According to TG-50 (AAPM Report 72) and ABRPhysicsHelp, What is a "single focused" design of a MLC leaf? What MLC configurations utilize this design?

The leaves are designed to reduce unnecessary beam attenuation by being shaped to match the beam divergence occurring in the planes perpendicular to the leaf motion (along the width and height of the leaf). The leaf ends are thus rounded tips and angled within the perpendicular plane of travel. Varian's Tertiary configuration and Elekta's Upper Jaw configuration utilize this design.

According to ABRPhysicsHelp, what is ultimate motivation for the pursuit understanding the mechanisms of FLASH, and the pursuit of its establishment as a radiation therapy modality? What kind of studies on the FLAH modality have been done so far?

The little research into it so far demonstrates its potential to significantly increase the therapeutic ratio. Mostly animal studies and some patient studies utilizing electron beams of modern day linacs.

According to ABRPhysicsHelp and TG-179, what is the definition of "image-guided radiotherapy"? Briefly describe in one to two sentences. Also list the two buzz words associated with this definition.

The management of variations in patient setup ("inter-fraction motion") and internal organ motion ("intra-fraction motion") through the acquisition of images during treatment.

According to ABRPhysicsHelp, What is the Beam Shaping system of a C-arm Medical Linac? Where does it approximately sit relative to the treatment room or Linac itself?

The portion of the linac treatment where patient-specific beam shaping takes place. It typically includes secondary collimators, MLC's, Blocks, electron cones, and wedges. It is located within the approximate bottom half of the Linac Treatment Head, the portion no longer in physical continuity with the accelerator waveguide.

What is the purpose of the "shutter" of Co-60 teletherapy units? What is a common error associated with it?

The shutter is source shielding that is in place at the beam window when the source is not be used for treatment. A common error associated with the the shutter is a "timer error" - the imprecision in the time it takes for the shutter to open and close.

According to ABRPhysicsHelp and TG-142, what is the recommended frequency of inspection of the dynamic delivery control capability of a linac? What is the tolerance per TG-142? What are the frequencies and the tolerances per MPPG 8.a? Elaborate a bit upon what it is?

There is no such test recommended by TG-142 Monthly; +-3% of dose delivered by open field under same dose objective. Assessment of SYNCHRONIZATION of the dose rate with other machine components utilized during VMAT/IMRT (gantry speed and MLC speed primarily).

According to ABRPhysicsHelp summary of TG-76, what are breath hold techniques in the context of respiratory motion management? Describe their fundamental principle within a couple of a sentences. What is the perhaps the most common variations of this technique? List and briefly describe each within a couple of sentences and what typical treatment cases for which they are useful.

These are techniques that combine procedures done for motion encompassing techniques and gating techniques: they aim to account for motion through imaging acquired at treatment SIMULATION and respiratory motion tracings utilized at treatment DELIVERY. They typically require couching patient to hold their breath with external monitoring or manage their breathing through some sort of feed back system such as external surrogate IR markers (Varian RPM system) or spirometers (Elekta ABS -Active Breathing Control - System). Deep Inspiration Breath Hold (DIBH) - patient holds in breath (deeply inhale) during a CT simulation, a plan is generated off of that planning CT, then the patient is gated according to respiratory phase coinciding with the breath hold position. Typically done for breast patients but could be used for other sites as well. Expiratory Breath Hold (EXBH) - patient exhales as much as possible during a CT simulation, a plan is generated off of that planning CT, then the patient is gated according to respiratory phase coinciding with the breath hold position. Not as typical as DIBH, but can be at times advantageous for abdomen cases.

According to ABRPhysicsHelp summary of TG-76, what are Forced Shallow Breathing with Compression techniques in the context of respiratory motion management? Describe their fundamental principle and typical applications of such techniques within a couple of a sentences.

These are techniques that use equipment to restrict patient breathing range, hence limiting the range of motion of a tumor. The most prevalent of such techniques is abdominal compression using a paddle apparatus that mounts to the treatment during simulation and treatment.

According to ABRPhysicsHelp and TG-147, in terms of operating principle and use, how do single camera systems differ from dual camera systems? Describe in a sentence. Give a current clinical example of such a system and briefly (one to two sentences) describe how it works?

Theses systems do not utilize the principles of stereoscopic imaging, but are really only designed to address respiratory motion. Real-Time Position Management (RPM) system from Varian - Uses a single camera, sensitive to IR and optical wavelengths, to monitor a surrogate with two IR markers as the patient breathes. The camera information is utilized to track the surrogate motion in the AP direction and trace a motion waveform representative of the patient's breathing pattern.

According to ABRPhysicsHelp, what is the "RTOG"? Describe within a few sentences, as necessary.

This is an United States organization funded by the National Cancer Institute (NCI) that is a source of radiation therapy clinical research protocols. It acts as a facilitator for the conglomeration of data from many institutions under the umbrella of a single research study and acts to eventually disseminate the results of that study.

According to ABRPhysicsHelp and your own experience, Describe the basic operating principles and mechanical design of the Cyberknife treatment modality. Summarize your description with a few sentences.

This is radiation treatment modality owned by Accuray that utilizes a magnetron powered Linac mounted on a high-precision movement arm. It only has a 6MV-FFF beam and a maximum field size of 60mm cone, so its considered only practical for SRS/SBRT treatments. It features a patient localization, tumor motion tracking, and respiratory tracking ("Synchrony") system powered individually or through the combination of orthogonal floor x-ray imaging, infrared monitoring, and landmark (fiducials and bony anatomy) tracking.

According to ABRPhysicsHelp, what is the basic clinical indication and method/motivation of I-131 Ablation therapy? Why Iodine-131? Describe within a few sentences.

Thyroid cancer. It is therapy that is usually adjuvant to surgical resection meant to "mop up any remaining thyroid cells" that may possess any cancerous cells. I-131 is the radioactive nuclide of choice because . . . (1) short half-live for quick delivery of dose. (2) high energy beta minus emissions. (3) One of the few radioactive isotopes that accumulates in the thyroid in great quantities.

According to TG-50 (AAPM Report 72) and ABRPhysicsHelp, What is the purpose of the tongue-and-groove designs common to all implementations of MLCs? What is amount of interleaf leakage (% of fluence) with such designs?

To help remove interleaf leakage. ~2%

According to ABRPhysicsHelp and TG-179, which medical accelerator vendor, IGRT systems employ MVCT?

Tomotherapy (its integrated into the medical accelerator)

According to ABRPhysicsHelp and your own experience, what is the key advantage of a Tomotherapy unit over a Linac when it comes to types of patient treatments?

Tomotherapy can treat long fields continuously, saving time and reducing room for setup error when it comes to treatment involving long fields.

According to ABRPhysicsHelp summary of TG-106, How long does it take to complete the commissioning of a conventional medical linear accelerator? Break down the total timeline into the timeline of key steps of the process. What the timeline for acceptance testing?

Total time: 4-6 weeks (1) 1.5 weeks for scanning (2) 1 week for point data collection (3) 1-2 weeks for analysis Probably week at most, but depends on energies being commissioned.

What is the operational description of a traveling waveguide design?

Traveling Waveguide Design - creates a temporally fixed yet spatially varied microwave that moves along with bunches of electrons at the same velocity. This traveling wave creates temporally fixed yet spatially varying electric fields that continue to accelerate the electrons with which they travel with.

According to ABRPhysicsHelp, what is the standard practice for determining the number of field junctions shifts needed for a crainal-spinal irradiation treatment? What factors contribute to this determination?

Tumor dose and cord tolerance dose. junction number = Tumor Dose/(Tolerance - Tumor Dose)

According to ABRPhysicsHelp, what is the targeted disease when treating a patient via Craniospinal Irradiation (CSI)? What anatomy is usually included in CSI treatments? Any procedures usually done before administration of CSI?

Tumors of the central nervous system that tend to spread through cerebrospinal fluid (CSF) ---- Medulloblastoma is most common. Brain, Spinal Cord, Cauda Equina Primary tumor is resected

According to ABRPhysicsHelp, What are the two materials x-ray targets typically made of in C-arm medical linacs? What are the beneficial characteristics of each? Do they significantly differ in their bremsstrahlung production efficiency for clinical energies?

Tungsten and Copper Tungsten: Has high melting point (~ 3400 degrees Celsius) Copper: decent metling point (~1000 degrees Celsius) but best thermal conductor (helps with water cooling efficiency of target) No, the change is very little.

According to TG-50 (AAPM Report 72) , what is the typical composition of MLC leaves? Which of the constituents is the most abundant and what percentage of this constituent makes-up a leaf? What is the rationale for having an alloy rather than a single metal?

Tungsten, Iron, Nickel, Copper (TINC). Tungsten; ~90-97% Alloy helps . . . (1) Overcome brittleness of Tungsten (2) imbue MLCs with low coefficients of expansion (important for interleaf separation)

According to ABRPhysicsHelp and TG-147, what is the basic design of all nonradiographic localization and positioning systems? What basic hardware systems are required? What is the basic operating principle of the hardware systems when working together? Describe in a single sentence. What is the buzz word that refers to this operating principle?

Two signal receivers and a transmitter. The geometries of systems relative to each other are known and utilized to associate two 2D-image projections to an original coordinate in 3-dimensions. "triangulation"

According to ABRPhysicsHelp and MPPG.9A, what are the types of machine/program checks that should be done on an annual basis for Linac-based SRS/SBRT programs? Tolerances for each? Emphasize tests unique to SRS/SBRT programs.

UNIQUE***(1) SRS Arc Rotation -> Not really sure what this is but seems to be a mode you could have the machine run at the console. Only need to QA it if use it, I am pretty sure we don't use it. -> 1 MU, 1 degree. (2) MU Linearity -> +-2% for MU >5 (3) Output -> +-1.5% (4) Isocentricity radiation/mechanical -> +-1 mm Unique **** (5) Small Field Data -> FSCFs and profiles -> +-2% for fields > 1cm; +-5% for fields sizes <= 1 cm. Unique****(6) E2E tests: localization of hidden target and dose accuracy -> 1mm and +-5%.

According to AAPM Online Learning Center Lecture, what are the specific buzz names of the two sub-categories of active scanning? Elaborate briefly upon each.

Uniform Scanning -> active scanning that uses modulator wheel range compensation. Pencil Beam Scanning -> active scanning that uses synchrotron energy variation range compensation.

According to ABRPhysicsHelp and MPPG.9A, what are the types of machine/program checks that should be done on a monthly basis for Linac-based SRS/SBRT programs? Tolerances for each? Emphasize tests unique to SRS/SBRT programs.

Unique***(1) Complete Isocentricity Test -> same as for daily (SRS=1mm;SBRT=1.5mm) (2) Couch Position Indicators -> Not really unique to SRS/SBRT program but tolerances different -> 1mm/0.5 degrees (3) Output Constancy -> +-2% (4) Safety Interlocks -> Including those unique to SRS/SBRT devoted systems.

According to ABRPhysicsHelp and TG-147, How do dual camera optical tracking systems work? Describe in a sentence. Give a current clinical example of such a system and briefly (one to two sentences) describe how it works?

Use surface imaging technologies to reconstruct surface maps of patients. AlignRT from VisionRT - a real-time surface imaging system that relies on two "pods" mounted within the treatment room. The pods both project a pattern onto a patient surface and capture the pattern reflected from the patient, which is then used to generate a surface contour.

According to ABRPhysicsHelp, what is he purpose of the beam steering coils in the bending magnet of a C-arm Linac? What are the names of the two steering coils pairs, what do they specifically do, and where do they approximately exist within the bending magnet system?

Used to make adjustable magnetic field strengths to direct the electrons so that they strike the target or scattering foils at the proper locations. the "properness" of the strike on the target or scattering foil is evinced by the flatness and symmetry of beam profiles. The two steering coil pairs are the radial and transverse steering coils The radial steering coils adjusts the electron beam radially: they adjusts its radius of curvature after the beams' exit of the accelerating waveguide and entering into arc trajectory imposed by the bending magnets. This translates into beam position adjustments along the inline direction the machine. The transverse steering coil adjusts the electron beam transversally: they adjust the the electron beam along abscissa of a patient's transverse plane (x-axes) when just before its arc trajectory. This translates into beam position adjustments along the crossline direction of the machine.

According to ABRPhysicsHelp, what is the "hallmark" (unique design characteristic) of the modern day linac?

Uses microwave energy (magnetron or klystron) to accelerate electrons.

According to ABRPhysicsHelp and TG-147, How do dual camera infrared tracking systems work? Describe in a sentence. Give a current clinical example of such a system and briefly (one to two sentences) describe how it works?

Uses surrogates placed on patient body to reflect infrared signals to infrared cameras. ExacTrac System from BrainLab - combines information from stereoscopic x-rays (tubes mounted on ceiling and detectors in floor) and signals from a infrared surrogate on patient and received by cameras near the patient feet or mounted within the treatment room.

According to ABRPhysicsHelp and your own experience, what lymph nodes are treated for a tangent field breast treatment? What lymph nodes are treated for 4-field breast treatments? what lymph nodes are treated for 5-field breast? Be specific in the designation lymph nodes.

Usually Axilla level 1 and part of Axilla level 2. Axilla level 1, 2 3, and supraclavicular nodes. Axilla lavel 1, 2, 3, supraclavicular, and internal mammary nodes (2-4 cm depth, run along both sides of sternum).

According to TG-50 (AAPM Report 72), There are three possible MLC-inclusive, radiation blocking configurations established by vendors of conventional Linacs. the Tertiary Collimator configuration is one of them. Which vendor established this configuration? Briefly describe the configuration. What are the advantages and disadvantages of this configuration?

Varian A pair of MLCs banks located down the beam line just after secondary jaw collimators. The leaves move along the "x-axis", along the axis perpendicular to the gantry rotation axis. Leaves are also on a "carriage", which helps reduce required length of MLCs leaves due to being farther along the beam path. Advantages: (1) Treatment machine is still capable of conventional blocking (assuming MLCs fail) Disadvantages: (1) Treatment head a bit more bulky. (2) Limited MLC Field Sizes and Positioning Range (since further along beam path and carriage, respectively)

According to ABRPhysicsHelp and TG-179, which medical accelerator vendor, IGRT systems employ kV-CBCT?

Varian OBI and Elekta XVI systems

According to TG-50 (AAPM Report 72) and ABRPhysicsHelp, which MLC configuration allows for "interdigitating" of leaves? What is leaf "interdigitating? What is the advantage of "interdigitating"?

Varian's Tertiary Collimator configuration Means a leaf can move past adjacent leaves on the opposing bank (Opposing bank leaves can move past each other). It enables the formation of "Island" fields (like what you would see in single-iso multiple-met SRS treatments).

According to ABRPhysicsHelp, how are magnetic and electric fields of a synchrotron varied as to accelerate a charged particle beam?

Varied synchronously to the particle beam's REVOLUTION FREQUENCY.

According to ABRPhysicsHelp and AAPM TG-256, What is "Range Straggling" in the context of a clinical proton beam?

Varying energy to change the depth of penetration.

According to ABRPhysicsHelp summary of TG-106, What typically transpires during acceptance testing of a medical linear accelerator?

Vendor performs a subset of spot checks, that would have to be done during the commissioning process, to verify the integrity of the accelerator installation. Physicist is usually present and has to sign off on the data or documentation for the tests performed.

According to ABRPhysicsHelp, what is the key difference between the two treatment delivery approaches currently employed in practice of proton therapy: "Fixed Beam" and "Gantry"? Elaborate. Which is more popular?

What is moved in positioning target. Fixed Beam -> moves patient via robotic treatment couch. Gantry -> Beam is moved via isocentric rotating gantry to typical limit of 180 degrees. The gantry delivery approach.

According to ABRPhysicsHelp and TG-100, What is a "failure"?

When a process lacks "quality" as defined by TG-100.

According to ABRPhysicsHelp, where does PET "avidity" (magnitude of relative signal) appear the greatest for PET scans following proton therapy treatments? What is the physical explanation of this, in one sentence?

Where protons had highest energy upon entry into tissue - upstream of proton beam and decreasing up to Bragg Peak. Nuclear interactions occur for higher energy protons, so greater number of positrons are produce and hence more signal occurs proximal to those generation sites.

According to ABRPhysicsHelp, Are Co-60 units still used in modern day (2000s)? Elaborate on where and why if still in use.

Yes - 3rd world countries use them since mechanically simple (break less) and do not require a stable power supply for clinical use.

How would you describe a isochronous cyclotron in a single sentence?

an accelerator system with design similar to a synchrocyclotron but attempts to compensate for relativistic increase in particle mass by increasing the magnetic field strength with increasing radius of the particle beam trajectory.

How would you describe a "synchrocyclotron" in a single sentence?

an accelerator that is COMPACT enough to mount directly on a GANTRY, hence no need for a beamline.

According to ABRPhysicsHelp and recent paper by Maxim Borisov et. al. "Racetrack Microtron---Pushing the Limits" , what is the operation and design principle of a Racetrack Microtron? Answer in one sentence. What are three advantages of a racetrack microtron? Ultimately, why are they not used for medical purposes today?

an accelerator that utilizes an accelerator waveguide as in modern day linacs to accelerate electrons in between the gap of two, magnetic-filed immersed dees as in a cyclotron. (1) easy energy selection (2) small overall machine size (3) beam transport simple -> can power multiple gantries. electron beam current tow low (micorAmps)

According to ABRPhysicsHelp, a medical C-arm Linac system is under vacuum from the ______ system to the ________ system?

beginning of the RF driver system; end of the bending magnet system.

According to TG-50 (AAPM Report 72), how many leaves are typically on each of the two banks of a conventional Linac?

between 20 to 80 leaves (a pair of 20 to 80 leaves).

How would one calculate the necessary angle of the cranial-field to match the divergence of the upper spinal field (assuming fields symmetrical about isocenter) for a cranial-spinal treatment?

collimator angle = arctan(field size along spine divided by two/SAD of spinal field)

According to ABRPhysicsHelp, what is another category of accelerators known designed as affordable "table-top" solutions for proton/particle therapy which can be utilized for a single vault? Are synchrocyclotrons part of this category?

compact accelerators; no

According to ABRPhysicsHelp, To what energies can a racetrack microtron accelerate electrons?

energies greater than 50 MeV

According to ABRPhysicsHelp, What are the constituent components of the "nozzle" following a particle beam line? What is the order of the components starting from the beam line-to-nozzle interface?

lateral beam scattering system -> ionization chambers -> snout holds

According to ABRPhysicsHelp and TG-179, what is the key advantage of MVCT over conventional kV CT? What is a disadvantage in comparison to a conventional kV CT? Answer both questions in one sentence.

less beam hardening and streaking artifacts for high Z materials. suffers from more noise due to dose reduction ("photon starvation").

According to ABRPhysicsHelp summary of TG-63, how much neutron production is generated by a hip protheses if treating with an energy greater than 10 MV in terms of percentage of prescription dose to surrounding bone? Is this contribution deemed negligible?

less than 0.5% of prescription dose to surrounding bone; yes

According to ABRPhysicsHelp, What is the bending magnet of at C-arm Linac? Where does it approximately sit relative to the treatment room or Linac itself?

magnet and collimation system that directs the electron beam from the accelerating waveguide towards the patient direction. It is inclusive of primary collimators, removable x-ray target, and the scattering foil/flattening filter carousel system. It is sits towards the top of the Linac Treatment Head , in conjunction with the accelerating waveguide but more towards the center of the treatment room

According to ABRPhysicsHelp, what are the typical construction materials of flattening filters in a C-arm medical Linac?

materials vary: Lead, aluminum, steel, and brass have been used "LABS"

According to ABRPhysicsHelp, what is pathological cause of Hodgkin's lymphoma? What are considered curative doses for both adults and children? Conventionally, how were such cases treated with radiation therapy? What tissues/organs could be targeted if treating Hodgkin's lymphoma?

mutations of the white blood cells. Adults -> 36 to 44 Gy Children -> 15 to 25 Gy Conventional Linac through variations of mantle and inverted-Y fields utilizing 6 MV photons. lymph nodes ---inguinal, iliac, axial, mediastinal, and cervical nodes --- and the spleen.

Given content provided by ABRPhysicsHelp, how would you describe the energy spectrum of an electron beam that exits a the bending magnet of Linac treatment head? How would you describe it upon exiting the treatment head, near the patient surface? How would you describe it upon entering the patient?

narrow energy spectrum, so narrow that one would say the electron beam energy is the monoenergetic. electron beam energy is broaden, but I guess one could say its mostly monoenergetic. electron beam energy spectrum is SIGNIFICANTLY broaden.

According to ABRPhysicsHelp, Relative to a synchrotron, what is the disadvantage of using energy degraders to modulate the range of charged particle beam in a cyclotron?

produce neutron contamination, more so than a synchrotron.

According to ABRPhysicsHelp, What is the purpose of the beryllium window of a C-arm Linac? Where is it approximately located? What comes after the this beryllium window? Where the does the x-ray target reside?

separates the high vacuum inside the bending magnet system with the outside air while minimizing attenuation of the beam. In a Varian Linac, towards the middle of the Linac Treatment Head and still in conjunction with the accelerating waveguide system. Beam Modifier and Collimation Components. (See image.) X-ray target resides just before the electron beam exits the beryllium window.

According to ABRPhysicsHelp, what is the treatment plan design principle (# of beams, angle/orientation of beams, aperture size) in the context of proton therapy when employing a "Multi Field Optimization" (MFO) technique?

setup beams and angles so that BEAM OVERALP IS MINIMIZED TO REDUCE SKIN DOSE.

According to ABRPhysicsHelp, what is the overall treatment plan design principle (# of beams, angle/orientation of beams, aperture size) in the context of proton therapy when employing a "Single-Field Uniform Dose" (SFUD) technique ?

setup beams and angles so that THE SHORTEST DISTANCE FROM THE SURFACE TO THE TARGET ARE ACHIEVED.

According to ABRPhysicsHelp summary of TG-76, what are gating techniques in the context of respiratory management techniques? Describe their fundamental principle within a couple of a sentences. What needs to be acquired, in addition to the preparations typical for modern day treatment planning, so that the treatment can be gated? What is the meaning of "Duty Cycle" in the context of such techniques? What is a typical duty cycle you would see in a clinic? What are some concerns if your duty cycle is too high? Too low?

techniques that aims to account for tumor by correlating beam activation at the treatment machine with patient's respiratory cycle during treatment DELIVERY. An AMPLITUDE or a PHASE window can be set that "gates" the beam --- if patient breathe is within a certain AMPLITUDE or PHASE, then the beam is triggered on. A time tracing of a patients respiratory cycle - Can be acquired by using internal or external surrogate markers. It is the ratio of beam-on time to total treatment time. it reflects the treatment delivery time efficiency of a gated treatment. ~30%-40% - but this can be lower depending on patient case. If duty cycle is too high - while treatment time will be a lot shorter, you will be treating the tumor as it moves more. If duty cycle is too low - you will be treating tumor mostly at a standstill but treatment time would be impractically high.

What is the rule-of-thumb for determining the optimal wedge angle (theta) given the treatment "hinge-angle" (phi), the angle between the normal axes of the flat sides of two wedges (or equivalently, the difference between the gantry angles of the two wedged-outfitted fields)?

theta = 90 degrees - phi/2

According to ABRPhysicsHelp and Khan, What is the typical clinical application of electron arc therapy?

treatment of curved surfaces, such as scalp, chest wall, ribs, and entire limbs.

According to ABRPhysicsHelp, Why would steel be considered as the raw material for constructing MLCs (multi-leaf collimators) to be used for proton therapy? (Why not tungsten as used in MLCs for photon therapy?)

tungsten was discovered to produce unacceptably high neutron dose.

According to ABRPhysicsHelp and TG-100, what is meant by taking a "reactive approach to safety"? What is the process called that identifies failure modes through this reactive approach and then attempts to establish key cause and efficacy of precautions currently in place?

undergo an evaluation of a process once a failure is identified. Root Cause Analysis - RCA

According to ABRPhysicsHelp and TG-100, what is meant by taking a "prospective approach to safety"? What are the four basic evaluation steps that TG-100 recommend occur for a prospective approach to safety? List them in the order performed.

undergo an evaluation of process before failures manifest. TG-100 is focused on developing techniques for performing this evaluation. 1. Process Mapping 2. Failure Modes and Effect Analysis (FMEA) Part I: identify failure modes for each process step 3. Fault Tree Analysis 4. Failure Modes and Effect Analysis (FMEA) Part II: identify causation, detectivity, and severity of each failure mode and input events.

According to ABRPhysicsHelp, when does radiation need to be delivered to a bone site to prevent ossification of bone that may occur after a surgery?

within hours BEFORE an operation associated with surgery.

According to ABRPhysicsHelp summary of TG-76, how much can lung tumors move on average? What is the max displacement one could expect? How does magnitude of displacement of lung tumors due to respiratory motion correlate with location? Is the movement of lung tumors between inhale and exhale phases rectilinear? Explain within a couple of sentences.

~ 1 cm (though I recall 2 cm from my reading of TG-76); ~ 5 cm. There is not really a correlation, except tumors typically near diaphragm tend to move more. Not necessarily - there can be an hysteresis effect.

According to TG-59, in the event that a 10 Ci Ir-192 HDR source fails to retract and manual retraction is required to the point staff has to enter the room, how much time would need to elapse for any one individual whom is 1 meter from the source to receive a dose equal to the yearly occupation dose limit (50 mSv, 5 cSv)? How much time if 25cm away (a little bit more than the average thickness of a person from their mid-line) from the source? In this event, if you want to limit the dose to the patient's target anatomy to a single fractional dose (340cGy to 700cGy), how much time do you have to remove the source from the the patient? When the source is in a traditional lead pig (4 inches diameter, 1 inch thick lead walls), at what distance from the pig would you need to be to expect an exposure rate of 1 mR/hr (~ 1 mrad/hr) if dealing with a 10 Ci source?

~ 1 hour; ~ 5 minutes ; ~ 1 to 2 minutes; 0.5 meters

According to TG-29, what percentage variation in dose uniformity is deemed acceptable by most protocols for TBI treatments?

~ 10%

According to ABRPhysicsHelp, What is the operating power of the RF driver system of a typical C-arm Linac?

~ 100 - 300 Watts

According to ABRPhysicsHelp, At what approximate kinetic energy does the accelerator electron gun inject electrons pulses into the accelerator waveguide?

~ 15 kV

According to ABRPhysicsHelp, What is the max beam energy typical Magnetrons are capable of producing? Which medical Linac vendors typically utilize Magnetrons in their accelerators?

~ 18 MeV Elekta, Accuray (Cyberknife and Tomo)

According to ABRPhysicsHelp Summary of TG-101, what is the recommended imaging slice thickness for planning CT scans or any imaging used for patient positioning during treatment sessions?

~ 1mm to 3mm

According to ABRPhysicsHelp summary of TG-76, when tumor motion is present due to respiration, what is a reasonable tumor displacement threshold marking when respiratory motion management techniques should be implemented?

~ 2 cm- if less than 2 cm, motion management is not necessary. (says 0.5 mm in TG-76 but this is a typo and Geisinger used 2cm)

According to ABRPhysicsHelp, what is the recommended block distance from patient surface if administering a photon beam treatment and if you would like to maximize penumbra sharpness but minimize electron contamination contributions to skin dose?

~ 20 cm.

According to ABRPhysicsHelp, what is the approximate Bremsstrahlung production efficiency of the electron beam striking a x-ray target in a C-arm Linac?

~ 20%, increases with energy

According to ABRPhysicsHelp, What is the resonance frequency of the accelerating waveguide? How does it compare to the frequency of the Klystron microwaves?

~ 3 GHz; should be approximately the same

According to ABRPhysicsHelp, How narrow is the pencil-beam of electrons created by the accelerator electron gun?

~ 3 mm

According to ABRPhysicsHelp, What is the energy discrimination window (in percent) afforded by the energy slit (copper collimator blocks) incorporated into the bending magnet of a C-arm Linac?

~ 3%

According to ABRPhysicsHelp, what are the dose rates exhibited by machines capable of FLASH Radiotherapy?

~ 30 Gy/s

According to ABRPhysicsHelp, what is the highest energy electron generated by medical betratrons?

~ 40 MeV

According to TG-62, TBI in-vivo patient dosimetry measurements should be in agreement with calculations by what percent?

~ 5%

According to ABRPhysicsHelp, How much of the useful beam do flattening filters attenuate in a C-arm Medical Linac?

~ 50-90% (depends on energy)

According to ABRPhysicsHelp summary of TG-63, a successful hip prosthesis relies on bone fusing to it to keep it in place. What approximate dose to a hip prosthesis tends to result in bone necrosis in 5% of patients, within 5 years? What about 50% of patients?

~ 52 Gy; ~ 65 Gy

According to Wepassed!, what is the typical amount activity and distribution of Cs-137 used T&O LDR procedures? Describe in units of mgRaeq, then mCi and U if possible.

~ 65 mgRaeq total = 1 x 15 mgRaeq in distal tandem + 2 x 10 mgRaeq in proximal tandem + 1 x 10 mgRaeq in left ovoid + 1 x 10 mgRaeq in right ovoid ~ 88 mCi total ~ 468 U total

According to TG-50 (AAPM Report 72) and ABRPhysicsHelp, For Upper and Lower jaw replacement configurations, what is the recommended radiation transmission tolerance? What about for the tertiary collimation configuration? Briefly explain the rationale for the tolerances.

~0.5%: MLCs are replacing solid jaws, so should be held to the same standards ~5%: MLCs are acting as custom blocks, so should be held to the same standards.

According to ABRPhysicsHelp, what is the typical beam diameter of a narrow proton beam spread out as a result of a lateral beam scattering system employing the passive scattering technique?

~10 to 20 cm

According to ABRPhysicsHelp and Dieterich tetbook, how many seeds that are to be used for an LDR procedure should by assayed, regardless of the seed form/type? Should this be done regardless of manufacturer seed assay? What is an alternative to a clinic performing a seed assay?

~10% of the total seeds ordered for a procedure. Yes Hiring third party service to perform seed assay, such as BARD.

What are typical SRS/SRT treatment prescriptions for Pituitary Ademona?

~15 Gy in single fraction -> nonfunctioning (not producing excess hormones = benign ) ~24 Gy in single fraction -> functioning (producing excess hormones = cancerous)

According to ABRPhysicsHelp summary of TG-76, If there is no method of motion management, what is the percent error in delivery of prescribed dose that could occur for modulated treatment fields (IMRT, wedges, VMAT, etc.)? If considering a treatment course of 30 fractions, what would be the approximate percent error in delivery of prescribed dose? Explain within a sentence. Would the dose error typically be larger or smaller for static treatment fields? Explain why within a sentence.

~20% ~2% - errors tend to be random though can be said to stem from systematic sources so they average out when considering all the fractions. Smaller - For modulate fields, there is an motion interplay effect that exacerbates dose errors.

According to ABRPhysicsHelp summary of TG-63, if generating a 4-field box treatment for a patient, what is a conservative assumption regarding the change of dose contribution to the body midpoint (relative to no implant) due to a single field traveling through an titanium rod implant, assuming all fields are equally weighted? What if a Co-Cr-Mo implant?

~20% lower in comparison to situation with no implant; ~ 30% lower in comparison to situation with no implant.

According to ABRPhysicsHelp and your own experience, at what magnitude of delivered prescription dose does a bolus placed for external beam breast treatments typically need to be removed for the remainder of treatment? Why?

~20-25Gy, so about half of typical breast prescription dose (50 to 50.4 Gy). Because, at these doses, the patient's skin begins to exhibit moist desquamation.

According to ABRPhysicsHelp, when looking at backscatter contributions to upstream tissue due to a lead electron shield, at what approximate distance upstream from the lead shield would backscatter contributions be deemed to cease?

~3 mm

According to ABRPhysicsHelp, what is a typical diameter of a cyclotron accelerator utilized for protons?

~3.5 to 5 meters

According to ABRPhysicsHelp, what are typical treatment times for stereotactic radiosurgery treatments administered through Gamma Knife?

~40 to 60 mins

According to ABRPhysicsHelp, what is the typical diameter for a synchrotron designed for protons? for carbon ions?

~8-10m; ~25m