CSH081 - Ultrasound in General Radiography, PET/CT/MRI, Radiographer Commenting, Patient Advocacy

Ways to keep exposure to a minimum in Nuc Med (5)

- Ensure proper education to patients and carers - Adopt conservative approach to dosing (ALARA) - Use of shielded uptake rooms - Maintain distance of 0.5m - Check patients imaging schedules so they can perform other modalities prior to nuc med to reduce exposure to imaging staff

How does a cyclotron work?

- Hydrogen ions are accelerated in a circular motion using magnetic fields or D's greatly increasing there velocity - Upon reaching a target material a carbon filter extracts the negatively charged particles to produce protons - Protons bombard the target producing unstable radionuclides - The amount of product produced is dependent on the cyclotron energy (MeV) used & length of time it is run for

Explain acoustic shadowing of needles used in U/S guided vascular access

- Metal needles have a high acoustic impedance and behave similarly to bone. - In contrast to bone, the acoustic shadow of the needle is not very obvious because of the small dimensions of the needle -> not wide or deep enough to distort the whole image. - A needle gives a very strong echo and appear as a hyperechoic line on an image - The posterior wall of the needle shaft which is very close to the highly reflective anterior wall is obscured. - A needle passing through the ultrasound beam in transverse section produces a shadow, seen as a black stripe, the approximate width of the needle - This artefact shows where the needle is crossing the beam but does not represent the path of the needle beyond it - If the needle is in longitudinal section no structures will be visualised deep to the length of the reflective element (this is dependent on the size of needle).

Explain the equipment used for U/S guided vascular access procedures?

- Should be performed using high-resolution linear array transducers (7.5 and 12 MHz are generally preferred, higher frequencies for superficial vessels and lower frequencies for deeper vessels) - Small-footprint probes (including the "hockey stick"-type probe) maybe helpful in paediatric patients or in areas where space is limited, such as near the clavicle. - Colour or Spectral Doppler imaging may be helpful for identifying flow in vascular structures and in aiding the differentiation of arteries and veins. Sterile probe covers should be available for all central access procedures - An additional person is often required to assist with sterile preparation of the ultrasound probe and machine operation - Echogenic needle tips for access may improve sonographic visibility - Longer intravenous catheters (>1.75 inches) are essential for peripheral venous access of deeper vessels identified with ultrasound.

What are some pitfalls of PET/CT (2)

- different breathing patterns in the PET & CT scan can cause mis-registration artefact leading to poor lesion localisation - high density contrast agents & metallic implants can cause overestimation of FDG activity -> specific algorithms need to be applied to correct this

Steps to performing a PET/CT/MRI

1) Prepare the radiopharmaceutical 2) Prepare the patient 3) Inject the patient 4) Scan the patient 5) Discharge the patient

What are the 7 universal ethical principles?

1. Justice: fairness 2. Autonomy: make own decisions 3. Beneficience: doing good 4. Nonmaleficience: do no harm 5. Veracity: telling the truth 6. Confidentiality: protect privacy 7. Fidelity: duty of care within scope of practice

How is a PET/MRI scan performed?

1. Patient positioned on scanning bed 2. MRI FASTVIEW localiser image acquired 3. MRAC + Dx MRI Sequences performed 4. PET images performed simultaneously

How is a PET/CT performed?

1. Patient positioned on the scanning bed 2. CT topogram performed 3. LDCT scan performed first 4. PET scan performed second 5. Dx CT performed last

What are the five components of a PET/MRI attenuation coefficient map

5x Compartments: 1. Bone 2. Air 3. Fat 4. Water 5. Tissue

What are clinical indications and patient prep for 68 GA Dotatate

68Ga-Dotatate Clinical Indications • Neuroendocrine tumours • Meningioma • Monitoring response to therapy (Lutate) Patient Preparation Dotatate • No fasting required • Written consent • 45 minute uptake

What are the advantages vs disadvantages of PET/MRI

Advantages Reduced radiation dose Reduction in MRI waitlists Additional functional imaging Superior soft tissue imaging Test of choice in paediatrics Test of choice for brain + prostate imaging Perfectly aligned simultaneous imaging L Disadvantages 60cm bore vs 80cm (PET/CT) < Level of patient compliance Larger scan room requirements Some patients contraindicated Safety requirements higher Scans take longer i.e. min 20mins No established protocols

Explain the longitudinal, long-axis approach for U/S guided vascular

Allows much better needle visualisation as the needle is more perpendicular to the ultrasound beam and multiple dots build up the image of the needle. Seen as a linear echogenic structure. Typically only see one echogenic line unless reverberation artifacts are present. Practice is require to keep the needle precisely within the image plane as any small movement out of the ultrasound beam results in the loss of the image of the needle. Sometimes referred to as InPlane approach The needle is placed inline with and parallel to the transducer. Both the needle shaft and tip are visualized.

What are the advantages/disadvantages of the longitudinal, long-axis approach for U/S guided vascular access

Allows the operator to visualize the entirety of the needle if in plane See in real time as the needle enters the vein in profile More technically challenging due to poor lateral resolution. Easier to loose site of the vein and accidently refocus the probe onto the adjacent artery with small moves of the ultrasound probe

Define hypoechoic

An area where the echo intensity is low - i.e. it is dark on the screen. However it is not anechoic - there are echoes present. Also echopenic

Explain the difference between veins and arteries

As tubular fluid-filled vessels, arteries and veins have a similar appearance on a grayscale ultrasound image. Both typically have an anechoic (black) lumen. Arteries have thicker walls that are slightly more hyperechoic (brighter) than the walls of veins. Arteries are less compressible than veins, but both are compressible with enough pressure. The ability to compress and coapt the venous walls with relatively minimal pressure is a useful way to distinguish a vein from an artery. If there is any doubt that a vessel may be arterial, the vessel should be imaged in the short axis and enough pressure applied to slightly deform the vessel, It should be observed for several seconds to determine whether arterial pulsations are present or absent. A non-compressible venous lumen indicates a thrombus. Doppler imaging may also be used to identify blood flow and to help differentiate arterial from venous flow. Any potential vessel should be evaluated for patency, diameter, depth, course, and surrounding or overlying structures.

What structures would be described as anechoic?

BLACK : fluid, blood, bile urine

What structures would be described echogenic/hyperechoic?

BRIGHT: bone, gas/air

What is the importance of CT/MRI in PET Imaging

CT + MRI crucial when performing PET imaging • Used to: 1.Provide attenuation correction 2.Precisely localise pathology 3.Report incidental findings 4. combines functional & anatomical imaging which allows identification of tissue composition (necrotic vs. metabolically active, useful for biopsy) 5. identification of pathological vs. benign lesion in checking for mets

How is CT contrast used in PET/CT?

CT Contrast • LDCT usually performed without contrast • Oral or IV contrast can be used with little effect on attenuation • Advantages of using contrast are seen in: • Distinguishing bowel from lymph nodes, peritoneal nodules & other structures • Also substantially increases CT accuracy

What is the disadvantage and advantage of using a dynamic image acuqisition in PET?

DIS • Larger storage requirements for dynamic data ADV • Manipulation of dynamic acquisitions, whereas static uses a sinogram

Explain the procedure involved in U/S PICC

During the procedure Local anaesthetic injected into the skin around the selected vein Using ultrasound as a guide the needle will be inserted into the vein Once the catheter has entered the vein, it is passed along using x-ray guidance The tip of the PICC will be positioned in one of the major blood vessels next to the heart. When the catheter is in the correct place an x-ray (chest / shoulder) will be taken to confirm placement. A PICC is inserted into a peripheral vein, such as the cephalic vein, basilic vein or brachial vein and then advanced through increasingly larger veins, toward the heart until the tip rests in the distal superior vena cava or cavoatrial junction. These lines are used for the semi long-term administration of total parental nutrition (TPN), drugs, chemotherapy, antibiotics and IV Fluids. The insertable portion of the PICC varies from 35-60cm in length. Some lines are designed to be trimmed to the desired length before insertion and others are simply inserted to the needed depth with the excessive left outside.

What a PMTs?

Photo-multiplier tubes • Convert the scintillation event and amplify the electrical signal (Now SiPM's) • Circuitry allows detection of true coincidence events to have occurred along the LOR • Single events are discarded

Explain the importance of chaperones

For professional integrity and personal safety, the sonographer should give equal consideration to their own need for a chaperone irrespective of the examination being undertaken or the gender of the patient. A chaperone is present as a safeguard for patients and sonographers and is a witness to continuing consent to the procedure. A formal chaperone should be offered to all patients undergoing intimate procedures or for any other procedure if the patient requests it, regardless of the patient's gender. No assumptions should be made on the basis of sex, age, culture or proposed procedure and no party should feel coerced into proceeding with an examination if an acceptable chaperone is not available A relative or friend of the patient is not an impartial observer and so would not be a suitable formal chaperone, but would be considered a witness.

Explain the reflection of needle related ultrasound artifact

Rough surfaces scatter ultrasound to all directions Smooth surfaces e.g. metal needles/cannulas behave like a mirror. Angle of incidence equals the angle of reflection. Smooth surfaces are best seen when the angle of incidence is zero (beam perpendicular to surface).

What are some additional radiation safety/logistical considerations of PET CT?

Higher energy photons i.e. 511keV (PET) versus 140kev (NM) Overall dose Approx. 8mSv (400MBq dose)- PET/CT PET radiopharmaceutical have much shorter half lives Potential higher radiation exposure to the public Injected activity set as a standard dose or weight based Education to patients on reducing radiation exposure Staff radiation dose higher than in general NM Time, distance & shielding critical Doses transported around the department in shielded containers and are much harder to transport

Explain annihilation coincidence detection

In a scanner there is series of PET detectors located 360 degrees around the patient. Two detector elements on opposite side of gantry are used to detect paired annihilation photons. If detected in coincidence the event is recorded. It is assumed the annihilation event has occured along the line between the two detectors (the line of response)

What are factors that influence assessment of the needle

Introducing the needle in a short 'in-and-out' or 'side-to-side' motion causes deflection of the adjacent soft tissues and makes the trajectory of the needle more discernible within the otherwise stationary field. Needles placed perpendicular to the beam are easier to visualise than needles parallel. Smaller gauge needles produce fewer artifacts but larger needles are more easily seen than smaller needles (particularly in cross-section). Principle of scattering can also be utilised to improve visualisation of the shaft of the needle. Injection of fluid has been shown to enhance needle and catheter tip visualisation Rocking the transducer into the path of the needle, if it has deflected out of the image plane. Injection of solutions, containing microbubbles from the needle into a fluid filled vessel can be seen with ultrasound (basis of one type of ultrasound contrast media) The needle tip can often be visualised even when the shaft cannot (tip with machine cut bevel has an irregular surface). When using a focused transducer, needles are seen best when within the focal zones When the needle shaft crosses the ultrasound beam an acoustic shadow is seen. Injection of air or microbubbles in solid tissues is not helpful because the acoustic shadow they produce further spoils further visualisation of deeper structures.

What structures would be described hypoechoic/echopenic?

Low intensity structures

Explain the difference between the traditional, medical model of care and a more patient centred model?

Medical Model Patient is quiet Patient is a recipient of treatment Provider is dominant decision maker Disease centred care Provider does most of the talking Patient may/may not comply with treatment plan Patient Centred Model Patient asks questions Patient is a partner in treatment plan Provider offers options and discusses with the patient Quality of life centred care Provider listens to the patient and talks less Patient more likely to follow plan that meets culture and values

Explain the transverse, short-axis approach for U/S guided vascular access

Needle is inserted steeply down, nearly parallel to the ultrasound beam. Typically in vascular access, vessels are viewed in cross-section. Enables adjacent structures to be easily visualised. But gives poorer visualisation of the needle when compared to longitudinal. Only one short segment of the needle is visible as an echogenic area on the display. The position of the needle tip can be established by rocking the transducer back and forth or by withdrawing the needle slightly. Seen as a highly echogenic (white) spot/dot which disappears immediately when the transducer is angled distal to it. The needle is placed perpendicular to the transducer

What is the normal uptake of 68 Ga Dotatate

Normal Biodistribution • Pituitary + thyroid + salivary glands • Stomach wall + spleen + liver • Adrenals • Pancreas • Prostate • Bowel + kidneys + bladder

What is ethical conduct

Practising according to rules or standards of practice (as prescribed by the MRPBA)

Explain how the needle tip is used in U/S guided vascular access

Recent advances have provided additional properties in needle technology that will improve needle echogenicity. Small angled indentations or notches have been created in the needle shaft resulting in an irregular surface that will increase the scatter of the ultrasound waves. Theoretically, the irregular or notched surface will provide a brighter signal and clearer ultrasound image at variable angles of needle insertion to the skin

What is the role of a sonographer with a chaperone

Sonographers should: honor patient requests to be examined with or without a chaperone reserve the right to insist on a chaperone being present and explain clearly why a chaperone is necessary they can delay an examination until a suitable chaperone is available if either patient or sonographer does not want the examination to go ahead without a chaperone present, or if either is uncomfortable with the choice of chaperone consider referring the patient to a colleague who would be willing to examine them without a chaperone, as long as a delay would not adversely affect the patient's health.

What is SUV?

Standard Uptake Value • A measure of relative uptake in an area of interest • Takes into consideration injected dose + time • SUV values in suspicious tissues are high i.e. >2.5 • SUV=Tissue Activity/Injected Dose

Explain the difference between static and dynamic ultrasound guidance

Static the static approach uses ultrasound to determine the vessel location and patency, assess surrounding structures, and mark the location to provide optimum placement for needle introduction. After determining this location, the procedure is performed without real-time ultrasound. Dynamic In a dynamic approach, the procedure is performed using realtime ultrasound observation of needle entry and placement and has been shown to be superior to the static approach in most situations.

What is patient advocacy?

Supporting, promoting, assisting and representing patients individual interests, needs and rights. Advising on suitability and application of procedures, Radiation benefits vs risks, Empowering patients to voice their own perspectives Advocate on behalf of the patient/client, when appropriate, within the context, of the practitioner's particular division of registration o Demonstrate understanding of the principles of patient advocacy and their application to the MRP o Communicate clearly with appropriate information and respond to pt. queries o Provide an environment where patient's feel safe enough to ask questions, be vulnerable, and an active consenting participant in their healthcare without judgment o Identify risks and limitations to protect and ensure patient safety and confirm requirements according to the clinical indications and patient interest.

What is empathy?

The ability to understand the patient's situation, perspective and feelings, and to communicate that understanding to the patient.

Define echogenic

This describes an area where the echoes are more intense - i.e. they are brighter on the screen. Also hyperechoic

Define echotexture

This is a description of the pattern of echoes. The echotexture could be described as: Fine Coarse Homogeneous (very even pattern) Heterogeneous (a mixed pattern)

Explain why ultrasound may be used in PICC placement?

The use of ultrasound guidance for PICC placement enhances vein assessment techniques, enhances overall success rate while decreasing complications ie. thrombosis. provides a better selection of optimal veins for access

Define anechoic

This term is used to describe an area that has no echoes - i.e. it appears completely black on the image. Fluid such as blood, bile or urine usually appears anechoic because there are no interfaces within the fluid to return any echoes. Also echolucent and sonolucent

What does a PICC look like on ultrasound

Two (2) echogenic parallel lines separated by an anechoic lumen. Positioned within the anechoic venous anatomy

Describe the use of ultrasound guidance for peripheral venous access

Ultrasound guidance for peripheral venous access can be an invaluable technique when short-term access is needed in patients who are difficult or impossible to access via the landmark technique. While ultrasound-guided peripheral access can be very effective when performed by an experienced individual, this procedure can be quite challenging, as the vessels are small and can be deep. Without sufficient operator experience with both intravenous access and ultrasound guidance for procedures, ultrasound may consume time and cause patient discomfort without benefits

What are the different approaches for U/S guided vascular access

Using basic B-mode imaging, the plane of the ultrasound image may be oriented relative to the vessel in the short (out-of-plane) or long (in-plane) axis. In a short-axis view, the image plane is perpendicular to the course of the vessel and to the needle (needle is "out of plane"). The vessel should appear as an anechoic circle on the screen with the needle visualized as a hyperechoic point in cross section. In a long-axis view, the image plane is parallel to the course of the vessel (needle is "in plane"). The image should show the course of the vessel across the screen and the shaft and point of the needle as it is advanced.

Explain the difference between one-person and two-person technique

Using dynamic visualization, it is possible for one person to perform the ultrasound while another person performs the procedure ("two person dynamic approach"). This provides the potential advantage of allowing the person performing the procedure to use two hands for the procedure itself and does not require the dual hand-eye coordination of directing the ultrasound transducer as well as performing the procedure. However, the two-person approach has the disadvantage of requiring additional personnel, and it may be more difficult for the practitioner doing the procedure to optimize the image positioning relative to the needle. In a one-person dynamic approach, the person performing the procedure holds the needle with one hand while directing the ultrasound probe in the other hand. While a one-person dynamic approach requires more experience, it is preferred by most advanced practitioners, as it allows for real-time hand-eye coordination.

Explain reverberation artefact

When U/S wave interact with a metal needle most of the energy is reflected back from the anterior needle wall. Occasionally some ultrasound penetrates the anterior wall and the beam gets into the shaft As the shaft consists of 2 parallel, very reflective walls, the ultrasound gets 'trapped' within the shaft by bouncing back and forth between the two walls giving a reverberation on every reflection They appear as multiple parallel lines The distance between consecutive lines is fixed and equals the diameter of the needle. No reverberation at the bevel as there is not 2 parallel surfaces.

What are CT findings which considered significant findings of a medically urgent nature which would require notification?

acute brain haemorrhage • signs of sub-arachnoid haemorrhage versus subdural haemorrhage • skull fracture • signs of subacute stroke • space occupying lesion in the brain • pulmonary embolus • dissecting aortic aneurysm • ureteric calculi.

What does an artery appear like on ultrasound?

anechoic the artery is round. the artery is pulsatile. on applying downward pressure vertically over the vessels, the muscular wall of the artery resists deformation and stays open, while a non-thrombosed vein gets compressed and the walls meet each other. Pulsed Wave Doppler will demonstrate a sharply accelerating, pulsatile flow in the artery

What does a vein appear like on ultrasound?

anechoic vein is ovoid on applying downward pressure vertically over the vessels, a non-thrombosed vein gets compressed and the walls meet each other Pulsed Wave Doppler will show a steady gradually changing flow in the vein

The sonographer must be satisfied that the formal chaperone will:

be of a gender approved by the patient or by the patient's support person be sensitive and respect the patient's dignity and confidentiality reassure the patient if they show signs of distress or discomfort be familiar with the procedures involved in a routine intimate examination stay for the whole examination and be able to see what the sonographer is doing, if practical be able to reliably judge whether the sonographer's actions are professionally appropriate and justifiable be prepared to raise concerns if they are concerned about the sonographer's behavior or actions. A record should be made in patient notes when chaperones are offered and used, and when they are declined, and any information, such as details of the chaperone and reasons for declining the chaperone, if relevant.

What are the advantages/disadvantages of the transverse, short-axis approach for U/S guided vascular access

better lateral resolution the requirement of moving the ultrasound probe dynamically to keep the needle tip on the screen shown to be easier to learn than long axis, resulted in higher success rate and took less time

Define echogenicity

is a description of how bright the tissue or structure is. - i.e. how intense the echoes are.

What is a Peripherally Inserted Central Catheter (PICC)?

is a long narrow tube (catheter) used to give medication directly into the blood stream without having to repeatedly insert a needle into a vein. possibly used in patients with poor venous integrity blood samples can be taken through a PICC for testing can be left in place for weeks / months depending on treatment guidance from medical imaging machines such as ultrasound and x-ray may be used during insertion

What is values-based practice?

o Aims to improve the health care professionals ability to engage with their patients in meaningful dialogue about decision making with mutual respect for differences in values o Values mean different things to different people o A partner to evidence-based practice in supporting clinical judgement in individual cases

What is values-based healthcare?

o Aims to improve the healthcare value ratio of patient outcomes per dollar expended o Improving patient care and saving dollars o Increase clinical efficiency and quality o Decrease overutilization, variability

Describe the piezoelectric crystal arrangement, footprint size, operating frequency (bandwidth), ultrasound beam shape and use of a curved ultrasound probe

piezoelectric crystal arrangement: curvilinear footprint size: big operating frequency (bandwidth): 1-5 MHz (usually 3.5-5 MHz) ultrasound beam shape: sector; the ultrasound beam shape and size vary with distance from the transducer, that causes the lack of lateral resolution at greater depths use: useful in all ultrasound types except echocardiography, typically abdominal, pelvic and chest why: greater penetration for deeper structures, lower frequencies = lower resolution, allows for greater depths and larger FOV however lacks lateral resolution.

Describe the piezoelectric crystal arrangement, footprint size, operating frequency (bandwidth), ultrasound beam shape and use of a linear ultrasound probe

piezoelectric crystal arrangement: linear footprint size: usually big (small for the hockey transducers) operating frequency (bandwidth): 3-17 MHz ultrasound beam shape: rectangular use: ultrasound of the superficial structures, breast, thyroid, scrotal, vascular and lumps and bumps

What is patient centered care?

providing care that is respectful of and responsive to individual patient preferences, needs, and values and ensuring that patient values guide all clinical decisions. Approach to healthcare treats each person as an individual not as a condition to be treated

Define professional ethics

standards of behaviour expected of members of a profession supported by consistent and well founded reasons established a foundation for professional practice based on universal principles of biomedical ethics

What are the advantages of digital PET?

• Advantages: • Reduced radiation dose both PET + CT • Reduced scan times • Improved spatial & temporal resolution • Faster time of flight

How are PET RPs administered and what happens after the injection?

• All PET RP's are administered via IV injection • Due to the radiation exposure injections take place in a variety of ways: - Hole in the wall - Automated injector device - Manual injection • After injection patient is kept in individual shielded uptake room • Remain in this room for the duration of their uptake time • 'Uptake time': time recommended for the radiopharmaceutical to adequately distribute around the body • Times vary from 0 mins up to 120 mins

Explain the uptake mechanism for 68 Ga Dotatate

• Analogue of somatostatin • NET's over express somatostatin receptors • Specifically SST2 • Dotatate efficiently binds to these receptors

What is 18F-FET's mechanism of uptake

• Artificial amino acid taken up by tumour cells • Malignant cells accumulate more tracer due to an increased number of amino acid transporters • This occurs during increased cell proliferation

What are some future opportunities for PET/CT and PET/MRI

• Biomarker Imaging • Immunotherapy response • Dose reduction • Paediatrics • Cardiac + respiratory gating • Therapy response • Additional pathologies + radiopharmaceuticals

What is 'Brown Fat' artefact?

• Brown fat is a type of adipose tissue • Innervated by the sympathetic nervous system • Activated in FDG PET scans by exposure to cold • Reduced by keeping the patient warm

What is the utility of CT attenuation corrected images versus non-attenuation corrected images

• CT allows a correction factor to be applied based on the complex range of densities within the body known as CT attenuation corrected image • Results in images of a higher diagnostic quality

What factors influence a practitioners choice between PET/CT or PET/MRI

• Clinical indication - certain modalities are better at visualising certain pathologies ie. lung cancer rule out PET/MRI • Location of suspected pathology • Equipment availability ie. timing of scan based on RP administration, will MRI b finished in time for this patient to still be hot • Frequency of scans - consideration of dose • Targeted vs global imaging ie. PET CT better for larger volumes • Patient compliance/suitability ie. claustrophobia, unable to lie still •Previous imaging ie. does the patient usually have PET/MRI, if so it may be better for continuity to have future scans done as PET/MRI • Radiopharmaceutical decay ie.

Explain PET acquisition convention

• Convention PET/CT works in bed positions • PET/MRI uses a similar concept called stations • Each bed position covers a specific area with 35% overlap • Each bed position is acquired for a pre-set time, usually 1-4 minutes • New PET/CT scanners allows for continuous bed motion imaging, with the bed translating at a pre-determined speed (cm/min)

Explain how PET detectors work

• Convert the energy of the photons into visible light • LYSO or LSO detectors used • Short decay times (40ns) + high light output (photons/MeV) • Used in both PET/CT + PET/MR

Explain the uptake mechanism for FDG

• FDG is an analogue of glucose • FDG is trapped in cancer cells due to glycolytic activity • Excreted from the body via the renal system • The reality of it is; Tumour cells tend to grow rapidly & as a result have higher rates of glucose metabolism.

What is the patient prep for FDG?

• Fasting for 4-6 hours • Reduce heavy physical activity for 24hrs • Keep warm on the way to the scan & during the uptake • Gap between chemo & scan (approx. 2-3 weeks) • Gap between RT & scan (approx. 3 months • BSL between 4-10mmol/L) • No surgery on the affected area (approx. 3 weeks) • 60min uptake in a quiet & darkened room

What are some applications of PET

• Imaging/quantification of cellular function & tumour detection • Establish the extent of disease (Staging) • Determining treatment methods i.e. Surgery, RT or Chemo • Monitor response to therapy • Localisation of sites for biopsy

What is the use of 18F-Fluoride Bone Scans

• Metastatic bone cancer • No special prep required • Alternative to HDP bone scans • Binds to the bones hydroxyapatite crystal

What are some issues with PET/MRI imaging in terms of patient/technical factors

• Patient compliance i.e. claustrophobia, prep • Difficult to distinguish between infection, inflammation & malignancy • If one component fails the entire system is down • Delayed tracer production • Artefacts caused by breathing, motion & internal metal

What safety considerations are there for PET/MRI

• Patient questionnaire/safety interview to screen patient for suitability • Patient factors: metallic implants ie. pacemakers, aneurysm clips, claustrophobia, ability to lay still + flat for long periods, frequency of urination, patient compliance • Additional Safety Features such as multi-zone entrance, safety warning signs, a lockable door, VESDA (Very Early Smoke Detection Apparatus) and staff training • All equipment must be MRI safe equipment eg. wheelchairs, patient trolleys, pressure injector, gases panel, equipment trolley • The high magnetic field strength: ferromagnetic objects will experience translational forces that will attract them to the magnet = projectiles • Gradients: Switching of gradients produces loud noises which must be protected against and induces electrical current which can causing twitching/tingling. • RF coils: can cause skin burns if looped incorrectly and in contact with the patient • Radiofrequency: RF power deposition results in heating of patient tissues.

What some indications for the use of 18F-FET Indications and relevant patient prep

• Primary brain tumours • Metastatic brain deposits • Recurrence following treatment • Clarify MRI findings Patient Preparation • 6 hour fast • MRI safety questionnaire • Written consent • Injected on the PET/MRI scanner

In what areas are FDG normally uptaken?

• Uptake will be noted in: • Brain • Kidneys + Bladder • Liver + Spleen • Heart • Skeletal Muscle • Bone marrow • Thyroid

What are some 18F-FBB indications and explain its uptake mechanism

• Used to identify brain & cardiac amyloidosis • Both AL + ATTR can be identified • Specifically binds to the amyloid β-pleated sheet structure

What is time of flight in a PET context?

• Uses difference in annihilation photon arrival time to estimate where in LOR the event occurred • Can identify events location within 7cm • Leads to improved image quality • No benefit in small structures

Define the following: • VIBE • STIR • HASTE • DWI • TSE • UTE • MPRAGE • FLAIR • SPACE • GAD

• VIBE: volume interpolated breath hold examination • STIR: short Tau inversion recovery • HASTE: half-fourier single shot turbo spin echo fat saturated • DWI: diffusion weighted imaging • TSE: turbo spin echo • UTE: ultra short echo time • MPRAGE: ultrafast gradient echo 3D • FLAIR: long Tau inversion recovery • SPACE: 3D TSE with variable flip angle • GAD: IV contrast used in MRI

What are x-ray findings which considered significant findings of a medically urgent nature which would require notification?

• acute dislocations • soft tissue signs of occult fractures • fractures around the hip and pelvis • disruption to the lines of alignment of cervical spine lateral projection and soft tissue signs of underlying injury • non alignment of the lateral masses of C1 and a break in the odontoid peg - fracture/dislocation of C1/C2 • fractures involving the thoracic, lumbar and sacro-coccygeal spine • foreign bodies in head, neck chest & abdomen, particularly in the paediatric patient • pneumothorax (spontaneous and tension), pneumomediastinum • mis-positioning of important chest tubes and lines • bowel (small and large) obstructions, sigmoid volvulus, pneumoperitoneum • ureteric calculi.

Explain beta + decay and annihilation radiation and how it relates to PET

•occurs in neutron deficient or proton rich radionuclides: 1. postively charged beta particle (positron) + neutrino emitted from parent 2. for beta plus decay to occur the transition energy must be above 1022keV 3. The positron emitted from the process of β+ decay are attracted to electrons as they are antiparticles to each other 4. After travelling a short distance following emission it is likely that the emitted positron will be brought into close contact with an electron and the two will annihilate 4. On annihilation the mass of the e- & positron is transformed into two 511keV photons which are emitted at 180 degrees to each other 5. Photons are then detected by the PET scanner to form the resultant image