RTT214 Midterm
Which type of IMRT treatment delivery has the gantry in a fixed position with an initial MLC pattern? A "Step-and-shoot" B dynamic MLC C "tomotherapy" D robotic IMRT
A "Step-and-shoot"
A wedge pair technique may effectively treat to a tumor depth of: A 0 - 7 cm B 7 - 9 cm C 9 - 12 cm D 12 - 15 cm
A 0 - 7 cm
A compensator can be used to compensate for: 1. a sloping skin surface 2. varying patient thickness over the target volume (or irregular patient surface) 3. non-uniform energy fluence across the treatment field A 1 and 2 only B 2 and 3 only C 1 and 3 only D 1, 2, and 3
A 1 and 2 only
In a constant SSD, three-field technique with the three fields eqully weighted, the dose at the input ports due tot he three fields is: 1. 1:1:1 2. 100%:100%:100% 3. 1:0.5:0.5 4: 1:1:0.5 A 1 and 2 only B 2 and 3 only C 2 and 4 only D 3 and 4 only
A 1 and 2 only
The wedge angle is determined by the tilt of the isodose lines at: 1. The 50% isodose line in low energy beams 2. A depth of 10 cm for high energy beams 3. The depth of the 20% isodose line in high energy beams 4. The depth of 5 cm for low energy beams A 1 and 2 only B 2 and 3 only C 2 and 4 only D 1 and 3 only E 3 and 4 only
A 1 and 2 only
The brachial plexus is most often included using which of the following techniques: 1. Mantle field 2. Inverted Y field 3. Pelvic box technique A 1 only B 2 only C 3 only D 1, 2, and 3
A 1 only
Which factors influencde the construction of a PTV from a CTV? 1. Patient set-up uncertainty 2. Organ motion 3. Proximity of critical structure 4. Extent of microscopic disease A 1, 2, 3 B 1, 3 C 2, 4 D 4 only E 1, 2, 3, 4
A 1, 2, 3
The side of an equivalent square of a rectangular field (a cm x b cm) is approximately given by A 2ab / (a+b) B √ab C (a+b) / 2 D none of the above
A 2ab / (a+b)
The skin dose, in the case of electron beams, is about A 80% to 90% B 30% to 40% C 100% D none of the above
A 80% to 90%
Bragg peak is: A An ionization maximum near the end of the range of a heavy charged particle B A maximum in the curve of activity and time for a patient and daughter radionuclide in equilibrium C A maximum concentration of Compton interactions D The maximum activity of an isotope
A An ionization maximum near the end of the range of a heavy charged particle
In an isocentric treatment technique, the dose is routinely normalized: A At the isocenter B At the tumor depth C At Dmax D On the surface
A At the isocenter
The machine that consists of a short metallic cylinder into two D-shaped cavities is known as the: A Cyclotron B Betatron C Microtron D Van De Graaf
A Cyclotron
The highly evacuated section of a cyclotron in which the particles are accelerated is called the: A Dee B Stripper C Waveguide D Injection chamber
A Dee
Which one of the following precautions would most effectively reduce radiation exposure to family members visiting a patient with an Iridium implant? A Double the distance between the patient and the family B Place a lead shield of one HVL thickness between the patient and the family C Reduce the visiting time by one-half D Place a personal radiation detection monitor on each visiting family member E All options are equally effective
A Double the distance between the patient and the family
All of the following are true of IMRT except: A IMRT dose distributions are always more inhomogeneous than conventional 3-D plans B In prostate treatment, IMRT can reduce rectal toxicity C A 3-D data set is required for IMRT planning D Immobilization is more important because of the tighter margins
A IMRT dose distributions are always more inhomogeneous than conventional 3-D plans
As electron energy increases, surface dose ___________ and depth of dmax __________. A Increases, increases B Decreases, increases C Increases, decreases D Decreases, decreases
A Increases, increases
Which of the following most significantly effects brachytherapy dose distributions? A Inverse square law B Absorption within tissue C Scatter within tissue D Tissue heterogeneities E Use of point or line source model
A Inverse square law
The use of a split beam technique in which half of the field is blocked has the advantage of: A Preventing beam divergence B Increasing the number of hot spots C Avoiding areas of increased dose D decreasing the number of cold spots
A Preventing beam divergence
Which of the following methods is most appropriate for determining if cerrobend blocks are free of internal voids? A Radiography B Visual inspection C Weighing the blocks D Comparison with other cerrobend blocks
A Radiography
The penumbra of a linear accelerator beam is: A Smaller than that of a cobalt-60 machine B Larger than that of a cobalt-60 machine C The same as that of a cobalt-60 machine
A Smaller than that of a cobalt-60 machine
Absorbed dose at a given depth divided by the dose in air dose at a fixed reference is the definition of: A TAR B TMR C TPR D PDD
A TAR
The entire right breast will be treated in your patient diagnosed with T1 N1 M0 infiltrating ductal carcinoma. The most likely field arrangement would be: A Tangential fields with subsequent tumor bed boost B Tangential fields with internal mammary and supraclavicular fields C Parallel opposed AP/PA fields with spinal cord blocked D Single field electron field to the entire breast with bolus
A Tangential fields with subsequent tumor bed boost
When dealing with brachytherapy sources, which of the following should be kept at a minimum to reduce exposure? A Time spent in the vicinity of the sources B Distance between the operator and the source material C Shielding between the operator and the source material D All of the above
A Time spent in the vicinity of the sources
Clinical target volume (CTV) A Volume enclosing tumor and subclinical spread B Tumor volume as determined by the radiation oncologist C Volume enclosing tumor, its subclinical spread, and a margin to include patient (or organ) movements and setup error D Defined by a specified isodose surface
A Volume enclosing tumor and subclinical spread
Conformal treatment improves tumor control. A Yes B No
A Yes
IMRT treatment gives better conformity compared to 3D-CRT treatments. A Yes B No
A Yes
In SAD techniques, the beams are weighted at target center. A Yes B No
A Yes
In SSD techniques, the beams are weighted at dmax points. Answer Choices A Yes B No
A Yes
Organs at risk (OAR) are the critical normal tissues or structures whose irradiation may significantly influence the treatment plan or dose presciption. A Yes B No
A Yes
The surface dose for clinical electron beams is: A about 75% to 95% B about 40% to 70% C less than 40% D none of the these values
A about 75% to 95%
The principle advantage of a universal wedge is in its ability to function at all: A beam widths B energy levels C SSD's D Hinge angles
A beam widths
When adjacent areas must be treated, it is best to: A cacluate gap necessary between the fields to prevent an overlap B set a 2-cm gap between all fields C rely on tattoos to prevent an overlap
A cacluate gap necessary between the fields to prevent an overlap
A patient's separation, also referred to as IFD, is generally obtained during the conventional simulation process using a: A caliper B contrast agent C radiopague marker D target-volume ratio E interfraction-motion ratio
A caliper
A(n) ______________ is a reproduction of an external body shape, usually taken through the transverse plan of the CA of the treatment beam. A contour B separation C SSD D SAD
A contour
What accessories are used to shape electron fields? A cutouts B blocks C compensators D transmission filters
A cutouts
The therapeutic depth (along beam central axis) for dose prescription is given by (electron beam): A depth of 90% of isodose level B depth of 50% of isodose level C peak depth D none of the above
A depth of 90% of isodose level
PDD is significantly affected by: A field size, energy, SSD, and depth B only field size, SSD, and depth C only energy, field size, and depth D only energy, SSD, and depth E only field size, SSD, and energy
A field size, energy, SSD, and depth
A dose-volume histogram A helps in optimizing the treatment plan B is the only method of optimizing treatment plans C is the best method for optimizing treatment plans D is a totally objective tool for optimization
A helps in optimizing the treatment plan
As the field size increases, the PDD: A increases B decreases C remains the same D there is no effect
A increases
The shielding around stored radioisotopes must be adequate to reduce radiation levels to: A less than 2 mrem/hr at 1 m B less than 5 mrem/hr at 1 m C less than 5 mSv/hr at 1 m D less than 5 rem/hr at 1 m
A less than 2 mrem/hr at 1 m
The calculation of dose at a point away from the central axis requires a knowledge of the: A off-axis ratio B tissue-phantom ratio C photon fluence D photon flux E kerma
A off-axis ratio
A shifting field arrangement (feathering) often used in treatment of brain and spinal cord is used primarily to: A prevent "hot" spots B prevent "cold" spots C increase the dose of the gapped area D spare overlaying skin tissue
A prevent "hot" spots
What determines the hinge angle? A the angle between two beams' central axes that share an isocenter B the angle of the 80% isodose line with a line perpendicular to the central axis of a wedges field C the angle of the 100% isodose line with a line perpendicular to the central axis of a wedges field D the wedge angle divided by 2
A the angle between two beams' central axes that share an isocenter
Each point along an isodose line has exactly the same dose. A true B false
A true
When equally-weighted, POP 18MV photon beams are used and the isocenter is placed at middepth (midplane) in the chest of a supine patient: A. the length of irradiated spinal cord will be greater in the anterior beam B. the length of the irradiated spinal cord will be greater in the posterior beam C. the length of irradiated spinal cord will be equal in both fields D. the spinal cord will receive most of its dose from the anterior beam
A. the length of irradiated spinal cord will be greater in the anterior beam
Which of the following factors will not effect the isodose curve? 1. Bolus 2. Lucite tray 3. Compensator A 1 only B 2 only C 3 only D 1, 2, and 3
B 2 only
Dmax is defined as: 1. Skin to isocenter distance 2. Depth in which 20% of dose is absorbed 3. Point of peak dose in an irradiated medium 4. Depth where electronic equilibrium occurs 5. Area of maximum penumbra A 1, 2, and 3 only B 3 and 4 only C 2 and 3 only D 1, 3, and 4 only E 4 only
B 3 and 4 only
Clinical proton generators consist of: 1. Linacs 2. Microtrons 3. Synchrotrons 4. Betatrons 5. Cyclotrons A 1, 2, and 5 B 3 and 5 C 2 and 4 D 1, 2, 3, 4
B 3 and 5
In clinical photon beam therapy planning, the PTV must be normally enclosed by: A 99% B 95% C 80% D 50%
B 95%
When planning a GYN implant, which point is dose calculated to? A W B A C J D F
B A
As photon energy increases, surface dose _______ and depth of dmax _______. A Increases, increases B Decreases, increases C Increases, decreases D Decreases, decreases
B Decreases, increases
The type of radium needles that have a higher activity at both ends are termed: A Indian club needles B Dumbbell needles C Balanced needles D Flip-flop needles
B Dumbbell needles
Heyman capsules may be used to treat the: A Vaginal vault B Endometrium C Vulva D Prostate
B Endometrium
The Sterling formula is a method to determine: A Extended distance B Equivalent square C Skin gap D Inverse square E Dmax F Penumbra
B Equivalent square
Which of the following has the shortest half-life? A Cesium - 137 B Gold - 198 C Iridium - 192 D Radon - 222
B Gold - 198
The angle between two beams is known as the: A Arc angle B Hinge angle C Wedge angle D Divergent angle
B Hinge angle
According to the text, methods of obtaining dose uniformity across field junctions include: I. dosimetric isodose matching II. separated fields III. junction field IV. half beam blocking V. geometric matching A I, II, III, and V B I, III, IV, and V C II, III, IV, and V D III, IV, and V
B I, III, IV, and V
The most desirable feature of a wedge pair technique is a __________ beyond the overlap region. I. Rapid dose build-up II. Rapid dose fall-off III. Uniform dose distribution A I only B II only C III only D I, II, and III
B II only
Which of the following is not an advantage of using a multifield approach? A Minimizes side effects B Increases integral dose C Reduces a potentially high dose in any single area D Provides more homogeneous dose distribution around target
B Increases integral dose
The Fletcher's suite application is an example of: A Interstitial low dose rate brachytherapy B Intracavitary low dose rate brachytherapy C Permananet implant brachytherapy D Injected, unsealed source brachytherpay
B Intracavitary low dose rate brachytherapy
In SAD techniques, the beams are weighted at dmaxpoint. A Yes B No
B No
In SSD techniques, the beams are weighted at target center. A Yes B No
B No
MLCs used with various linacs are identical. A Yes B No
B No
The aim of treatment planning is to plan a treatment that gives the prescribed dose to the target volume of interest and no dose to surrounding normal tissues. A Yes B No
B No
The skin dose can be reduced by using a bolus (of less than the buildup thickenss) for treatment with accelerator photon beams. A Yes B No
B No
Beam modifiers such as wedges would most likely be used in a treatment plan for: A Metastatic bone lesion in the femur B Primary cancerous lesion in the rectum C Metastatic bone lesion in the cervical spine D Primary cancerous lesion in the prostate
B Primary cancerous lesion in the rectum
If the physician changes the field size after the treatment plan has been approved, the therapist should: A Record the new field size and follow the plan as approved B Record the new field size and submit the change to physics for new calculation C Reduce the monitor units by 1 if the field size has increased by 1 cm D Increase the monitor units by 1 if the field size has increased by 1 cm
B Record the new field size and submit the change to physics for new calculation
The concept of tissue-air ratio (TAR) is most commonly employed for calculations involving: A Overlapping fields B SSD varying fields C Separated fields D Opposed fields
B SSD varying fields
According to the Bragg-Gray cavity theory, the ratio of dose to the surrounding medium to the dose to cavity air is given by: (Assume cavity size to be infinitesimally small) A The ratio of mass absorption coefficient of medium to that of air for the photons crossing the cavity B The ratio of mass stopping power of medium to that of air for the electrons crossing the cavity C The ratio of electron density of medium to that of air D Roentgen-to-cGy conversion factor for the medium
B The ratio of mass stopping power of medium to that of air for the electrons crossing the cavity
For isocentric parallel opposed equally weighted photon fields: A The target dose specificationpoint is the depth of Dmax B There is reproducibility of setup with less chance of geometric miss C Treating one field per day is less harmful to normal tissues than treating both fields per day D The peripheral dose increases with increasing energy for constant midline dose
B There is reproducibility of setup with less chance of geometric miss
Protracted or fractionated dose are better tolerated by tissue than single doses because: A Tissue tolerance increases as dose increases B Tissue repair occurs between exposures C Fewer cells will be struck by radiation D Radiation damage cannot occur in previously killed cells
B Tissue repair occurs between exposures
Wedges are used for all of the following except: A To increase dose homogeneity for breast tangent fields B To increase the anterior hot spot for a larynx treated with lateral opposed fields C To increase dose homogeneity for othogonal fields in partial-brain treatments D As a missing-tissue compensator E To increase dose homogeneity in a three-field plan (anterior and two opposing laterals)
B To increase the anterior hot spot for a larynx treated with lateral opposed fields
Gross tumor volume (GTV): A Volume enclosing tumor and subclinical spread B Tumor volume as determined by the radiation oncologist C Volume enclosing tumor, its subclinical spread, and a margin to include patient (or organ) movements and setup error D Defined by a specified isodose surface
B Tumor volume as determined by the radiation oncologist
A remote after-loading device is useful in brachytherapy treatments because of the: A long half-life of the radioisotope used B advantages in reducing the radiation exposure to personnel involved in treatment C high energy of the gamma rays from the after-loading unit D improved cure rate E reduction in patient discomfort
B advantages in reducing the radiation exposure to personnel involved in treatment
Which of the following is most likely to be treated using a remote afterloader? A pterygium B cervical cancer C ocular melanoma D prostate cancer
B cervical cancer
As the depth increases, the PDD: A increases B decreases C remains the same D there is no effect
B decreases
PDD, for use in SSD type of treatmetns, is normalized to: A skin dose B dose at dmax C dose at d5 cm D dose at d10 cm
B dose at dmax
What is(are) spatial representattion(s) of the magnitude of the dose produced by a source of radiation? A treatment planning B dose distributions C dose calculation matrix D dose-volume histogram (DVH)
B dose distributions
The percentage depth dose (PDD) curve is an example of a two-dimensional representation of the variation of dose. A true B false
B false
What is an advantage of remote afterloading? A less invasive for the patient B limits exposure to the patient and personnel C decreased treatment time D allows the patient to have a semiprivate form
B limits exposure to the patient and personnel
Which of the following is the most favorable situation for the overall goal of radiation therapy? A radiosensitive tumor and radiosensitive normal tissue B radiosensitive tumor and radioresistant normal tissue C radioresistant tumor and radioresistant normal tissue D radioresistant tumor and radiosensitive normal tissue
B radiosensitive tumor and radioresistant normal tissue
In opposing field techniques specifically designed for treatment of breast might be: A AP/PA arrangement B tangential fields C box technique D right and left laterals
B tangential fields
The goal of radiation therapy planning is to deliver an evenly distributed radiation dose to the ________ while minimizing the dose to the normal surrounding tissue. A isodose lines B target volume C hinge angle D penumbra
B target volume
The wedge angle is the angle of: A the wedge B tilt of the isodose curve with respect to the normal to central axis at a reference depth C tilt of the gantry while using the wedge D all of the above
B tilt of the isodose curve with respect to the normal to central axis at a reference depth
Field weighting is used: A when tumors are centrally located B when contribution from any of the fields needs to be reduced or increased with respect to other fields C in rotation therapy D in single field treatments
B when contribution from any of the fields needs to be reduced or increased with respect to other fields
Rotational x-ray beam therapy is acceptable: 1. When the external contour of the patient is fairly cylindrical 2. When blocking is required to shield sensitive structures 3. When target volume is small 4. When target volume is centrally located A 1, 2, and 3 B 2, 3, and 4 C 1, 3, and 4 D 1, 2, 3, and 4
C 1, 3, and 4
Geometric penumbra width increases with increase in: 1. Source (or focal spot) diameter 2. Source-diaphragm distance 3. Source-surface distance 4. Depth in the patient A 1 and 2 only B 2 and 3 only C 1, 3, and 4 only D 1, 2, 3, and 4
C 1, 3, and 4 only
In electron beam therapy, the dose perscription point is generally: A the patient's skin surface B reference depth of calibration C 90% isodose depth D none of the points
C 90% isodose depth
Which technique is most often used for the treatment of superficial tumors that extend to a depth of 7 centimeters? A Rotational therapies B Parallel opposed therapies C Angled fields using wedge-pair technique D Angled fields without wedges
C Angled fields using wedge-pair technique
In a fixed SSD technique, the dose is routinely normalized: A At the isocenter B At tumor depth C At Dmax D On the surface
C At Dmax
The most commonly used axial image database for a 3-D treatment planning computer is: A MRI B PET C CT D US
C CT
Which of the following machines does not accelerate electrons? A Microtron B Betatron C Cyclotron D X-ray tube
C Cyclotron
A patient is planned for equally weighted, parallel-opposed 6 MV photon fields treating the mediastinum, AP thickness 22 cm. If the beam energy is changed to 18 MV photons, all of the following would decrease except: A MU B Skin dose C Depth of maximum tissue dose D Percent variation in dose across the treated volume
C Depth of maximum tissue dose
The amount of geometric penumbra is not effected by the: A SSD B SDD C Field size D Source Size
C Field size
High LET radiation usually has: A An RBE of 1 B An RBE of 0 C High RBE D No relation to RBE
C High RBE
A method for correcting an isodose chart for contour irregularities is the: A Impedance method B Field shaping method C Isodose shift method D Isocenter method
C Isodose shift method
Which of the following accounts for target motion and uncertainty in positioning? A GTV B CTV C PTV D treated volume
C PTV
The cyclotron may produce _________ beams. A Electron B X-ray C Proton D Gamma ray
C Proton
Radioactive sources should be transported around the treatment facility in: A Sterile bags B Biohazard bags C Shielded containers D Sterile boxes
C Shielded containers
Planning target volume (PTV) A Volume enclosing tumor and subclinical spread B Tumor volume as determined by the radiation oncologist C Volume enclosing tumor, its subclinical spread, and a margin to include patient (or organ) movements and setup error D Defined by a specified isodose surface
C Volume enclosing tumor, its subclinical spread, and a margin to include patient (or organ) movements and setup error
To minimize the gap between two adjacent fields abutting at a depth. A a posterior field alone can be used B an anterior field alone can be used C a half beam block can be used
C a half beam block can be used
Dose distribution in multiple levels may be necessary when the following area is treated: A pelvis of thin patient B breast of a thin patient C breast of a large patient D brain of an obese patient
C breast of a large patient
Radium has largely been replaced with 137Cs for brachytherapy because radium sources: A have less filtration than 137Cs sources, making them more likely to bend and fracture B have greater energy, making them prone to radiation damage C can emit radon gas, which is an alpha emitter D have a much longer half-life E deliver a dose distribution less homogeneous than 137Cs in tissue
C can emit radon gas, which is an alpha emitter
dmax is most dependent on: A SSD B field size C energy D total dose E thickness of tissue
C energy
Forced shallow breathing technique is used to control: A compression B imaging C motion D interfraction dose
C motion
During IMRT treatments, how is the intensity of the beam altered? A insertions of a wedge B movement of the collimators C movement of the MLCs D fluctuations in the beam energy
C movement of the MLCs
Bragg-Gray cavity theory relates ionization produced in an air cavity in a medium to the dose in the medium using the: A Roentgen to rad f-factor B Mayneord F-factor C stopping-power ratio D decay constant E mechanical equivalent of heat
C stopping-power ratio
A universal wedge is a wedge A of the largest wedge angle in use B that can be used with any accelerator C that can be used for many field sizes D none of the above
C that can be used for many field sizes
The rapid fall-off of dose around a 137Cs source in a 5 cm radius of tissue is due primarily to the: A the low energy of the radiation B the attenuation in tissue C the inverse square law D the attenuation of beta rays E the attenuation of alpha rays
C the inverse square law
The radiation oncologist should mark on each CT slice: A the gross tumor area B the clinical target area C the planning target area D the irradiated area
C the planning target area
TAR is: A corrected for SSD with Mayneord's F-factor B dependent on SAD C used for irregular fields and rotation calculations D not defined for photon beams below 3 MeV
C used for irregular fields and rotation calculations
An autoradiograph is taken to: A determine the energy of the source B check source placement in the patient C verify uniformity of source D determine source strength
C verify uniformity of source
For nonisocentric treatment techniques, ______ is the factor of choice to demonstrate central axis dose at a given depth. A TMR B TPR C TAR D %DD
D %DD
Organs that can be affected by motion are the: 1. lung 2. liver 3. pancreas A 1 and 2 B 2 and 3 C 1 and 3 D 1, 2, and 3
D 1, 2, and 3
According to ICRU specifications, the wedge angle is defined at: A Depth of 50% isodose line B Depth of 80% isodose line C Depth of Dmax D 10 cm depth
D 10 cm depth
At what point does the treatment planning process begin? A dose determination B beam delineation C organ segmentation D CT imaging
D CT imaging
___________________ contours are the most accurate of all transverse contouring methods. A Solder wire B A thermoplastic tube C A plaster strip D CT-generated
D CT-generated
Treatment volume (TV) A Volume enclosing tumor and subclinical spread B Tumor volume as determined by the radiation oncologist C Volume enclosing tumor, its subclinical spread, and a margin to include patient (or organ) movements and setup error D Defined by a specified isodose surface
D Defined by a specified isodose surface
Which of the following is an advantage of HDR over LDR? A HDR is noninvasive B HDR dosimetry is simpler C Treatment time is decreased from 72 hours to 24 hours D HDR can be given on an oupatient basis
D HDR can be given on an oupatient basis
Which of the following factors can be corrected to adjust the isodose lines of beams with oblique incidences? I. PDD II. TAR III. TMR A I and II B I and III C II and III D I, II, and III
D I, II, and III
High dose rate (HDR) brachytherapy procedures should be performed in: A A private surgical suite B In a private hospital room C In a patient examination room D In a shielded vault
D In a shielded vault
One disadvantage of radium is: A It has a long half-life B It decays by alpha emission C It is not as effective as other radioisotopes D It decays to form a radon, a dangerous gas
D It decays to form a radon, a dangerous gas
What invention allowed IMRT to become a reality? A Cerrobend B %DD C Tomotherapy D MLC E CT
D MLC
Absorbed dose at depth x 100% = absorbed dose at Dmax is the definition of: A TAR B TMR C TPR D PDD
D PDD
Generally, which term would describe the largest volume of tissue in the patient planning process according to ICRU Report 50? A GTV B CTV C VTV D PTV
D PTV
Using a lateral dose profile taken at depth of Dmax, the distance between the 90% and the 10% dose values is the description of the: A Geometric penumbra B Effective field size C Treatment field size D Physical penumbra
D Physical penumbra
A monitor unit is: A Part of the hardware of a record and verify system B A length of time (fraction of a minute) that the linac beam is turned on C A unit used to describe the electron energy of a linac D Proportional to the dose delivered at a reference point
D Proportional to the dose delivered at a reference point
The term "step-and-shoot" is sometimes used to describe which IMRT delivery technique? A Helical tomotherapy B Serial tomotherapy C IMAT D Segmental MLC - IMRT E Dynamic MLC - IMRT
D Segmental MLC - IMRT
Nursing and other patient care staff caring for an admitted patient undergoing low dose radiation (LDR) brachytherapy should: A Wear gown and gloves to prevent radioactive spills B Wear a face mask to prevent inhalation of radioactive materials C Wear goggles to prevent splashes of radioactive material D Use standard precautions and perform duties as quickly as possible
D Use standard precautions and perform duties as quickly as possible
When more than two planes of sources are used, it would be called a: A Stereo implant B Single-plane implant C Orthogonal D Volume implant
D Volume implant
The most important characteristics of the electron beam isodose curves that influence treatment planning are: A constriction of 80% to 90% isodose curves B ballooning (or lateral spred) of 50% to 20% isodose curves C therapeutic depth D all of the above
D all of the above
Treatment fields can be shaped using: A standard blocks B custom made blocks C a multifield collimator D all of the above
D all of the above
Treatment planning and delivery systems are rapidly evolving to accomplish all of the following except: A increase tumor effects B reduce normal tissue damage C improve patient safety D decrease patient care
D decrease patient care
The shape of the isodose distribution for a tandem and ovid treatment is: A apple shaped B triangular C mushroom shpaed D pear shaped
D pear shaped
During monthly linac QA, film is commonly used to check the radiation field size, with marks on the film indicating the light-field edge. The light field should coincide with the ___________ isodose line at dmax. A 95% B 90% C 80% D 75% E 50%
E 50%
Which of the folloiwng could be used as a tissue compensator? A Shaped bolus B A wedge C Cerrobend D Dynamic MLC E All of the above
E All of the above
"Skin sparing" is reduced in photon beams by all of the following except: A Using bolus B Treating through a plaster cast C Using a beam spoiler D Treating tissue under a skin fold E Increasing photon energy
E Increasing photon energy
Why are 125I and 103Pd typically used for prostate implants? A The cost/source is small compared to alternatives B Large dose anisotrophy protects structures superior and inferior to implant C The smaller source size for each allows more flexibility in the implant D Reduced radiation safety issues E Lower energies reduce the dose to surrounding critical structures
E Lower energies reduce the dose to surrounding critical structures