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Nucs Board Review > Clinical > Flashcards

Clinical Flashcards

1
Q

2 reasons for the T-half you get with chromium labeling.

A

Elution of Cr from normal RBCs

the fact that you’re labeling all ages of RBCs (some of which are already 120d old)

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2
Q

What are the units for bone density?

A

a. BMD = g/cm2

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3
Q

BMD - basis set determination (I think this is synonymous with basis set decomposition). How does this affect BMD and soft tissue attenuation? (2 marks)

A

Mathematical theory used in DXA, assumes that the person is made of only two densities (bone and soft tissue). Does not take into account fat density, and assumes that fat density is combination of a positive amount of soft tissue and negative amount of bone. This will falsely decreased the BMD. If the amount of marrow fat is known, a correction factor can be applied to the BMD measurement.

three dimension basis set has more information since we can image bone, soft tissue, and adipose tissue separately while with the two dimension set in Fig. ​Fig.77 the adipose tissue appears as a positive amount of soft tissue and a negative amount of bone.

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4
Q

.Dimensionality and noise in energy selective x-ray imaging

A

X-ray transmimssion factor through a physical object can be decomposed into equivalent densiities of two any two designated materials.

Ignoring fat can artifically reduce BMD. When marrow fat is known, DXA estimation of BMD can be corrected

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5
Q

Why is the femoral neck the reference standard for osteoporosis and fracture risk?

A

This site has been the most extensively validated, and provides a gradient of fracture risk as high as or higher than that of many other techniques.

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6
Q

Advantages of central DXA

A

Consensus that bone mineral density results can be interpreted using WHO T‐scores
Proven ability to predict fracture risk
Basis of new WHO algorithm for predicting fracture risk
Proven for effective targeting of antifracture treatments
Good precision
Effective at monitoring response to treatment
Acceptable accuracy
Stable calibration
Effective instrument quality control procedures
Short scan times
Rapid patient set up
Low radiation dose
Availability of reliable reference ranges

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7
Q

Name 3 advantages of DEXA over radionuclide bone densitometry.

A

Improved resolution; Improved image quality; Improved precision; Reduction in scan time to 2-5 minutes

x-ray tube as the radiation source. The device is pulsed alternatively at two energies- usually 70 and 140 keV. The attenuation between bone and soft tissue is greater for the low energy beam. By entering both attenuation profiles into an equation, the soft tissues can be subtracted and an attenuation profile of the bony components can be calculated [3,4]. The radiation dose from the procedure is only about 1/1000 of that from a routine spine film.

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8
Q

What is the LSC in bone densitometry and what does it signify?

A

Amount by which one BMD value must differ from another in order for the difference to be statistically significant at a 95% confidence level

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9
Q

DXA – times when technologist have to do precision testing

A

After: basic scanning skills have been learned; 100 patients have been scanned; when a new DXA system is installed; and whenever their skill level has changed.

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10
Q

Name 2 methods of producing photons of two different energies in DXA?

A 
Voltage switching (e.g. Hologic) - continuously switch voltage between high and low values
K-edge filtering (e.g. GE, Norland) - Use carefully chosen metal filter (thin sheet of a special metal) to create two separate energy peaks in x-ray spectrum
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11
Q

Why do we use the Robinson formula when calculating GFR? What happens to GFR is we don’t use it?

A

Robinson formula calculates ideal body weight. Using IDW in a GFR calculation is more accurate than actual body weight. If you don’t apply it, you will overestimate GFR in fatter people.

Cockcroft and Gault equation:
CrCl = [(140 - age) x IBW] / (Scr x 72) (x 0.85 for females)

Robinson is a formula to calculate ideal body weight:
Men: Ideal Body Weight (in kilograms) = 52 kg + 1.9 kg for each inch over 5 feet
Women: Ideal Body Weight (in kilograms) = 49 kg + 1.7 kg for each inch over 5 feet

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12
Q

A patient presents after dental extraction while on bisphosphonates. He presents with pain in the mandible. What is the most likely consideration?

A

Osteonecrosis of the jaw

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13
Q

Define acronym:

a) RIS
b) PACS
c) DICOM

A

a) Radiology Information System
b) Picture Archiving and Communication System
c) Digital Imaging and Communications in Medicine

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14
Q

What is a MeSH and what does it mean to explode a MeSH?

A

MeSH (Medical Subject Headings) is the (U.S.) National Library of Medicine’s controlled vocabulary thesaurus and is used for indexing articles for MEDLINE

n PubMed, MeSH (Medical Subject Headings) terms (as well as any subheading that is the top of a “subheading tree”) are “exploded” automatically to retrieve citations that carry the specified MeSH heading (or subheading) and also retrieve citations that carry any of the more specific MeSH headings (or subheadings) indented beneath it in the Tree structure

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15
Q

What is the difference between a systematic review and a metaanalysis?

A

Systematic review - literature review that collects and critically analyzes multiple research studies or papers.

Meta-analysis - statistical analysis that combines the results of multiple scientific studies.

The aim then is to use approaches from statistics to derive a pooled estimate closest to the unknown common truth based on how this error is perceived.

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16
Q

Phase 1, 2, 3 trials (know what each phase involves)

A

1 = initial trial of a drug in humans for dosing, safety, and early efficacy (20-80 patients)

2 = Drug safety and efficacy in a specific disease setting (100-300 patients)

3 = Larger trial comparing to best available therapy to confirm efficacy and safety; often used for drug approval (1000-3000)

4 = after FDA approval to gain info about drug risks and benefits

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17
Q

Name 6 roles of a president of a medical meeting before, during and after the meeting.

A
  • Prepare the agenda
  • Convening the Assembly
  • Ensure the quorum
  • Open meeting
  • Facilitate the meeting
  • Ensure that meeting keeps to schedule
  • Verify the right to speak and interventions
  • Close the meeting
  • Ensure that minutes are produced
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18
Q

Name 3 ways a nuclear medicine physician can be a health advocate.

A
  • Clearly explain radiation protection standards to others
  • Precise information to patients about a possible post-treatment pregnancy with iodine
  • Inform nursing patients about the duration of cessation of breastfeeding
    Petition for purchasing of CZT semiconductor gamma cameras which would enable reduction of patient dose while maintaining equivalent image quality and scanning time
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19
Q

You see requisition for 12 year old and “hypothyroid”

A
  1. Phone the referring physician to clarify the indication for the study (Health advocate, Medical expert)
  2. If the study was indeed ordered to evaluate hypothyroidism, inform the referring physician that this is not the appropriate test
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20
Q

You work in a small department with two dual head cameras. One head on one of the cameras is not working.
a)List 2 actions to take to decrease chance of equipment breakdown

        b) List 3 ways you would prioritize patients if you had to cancel patients
   	 c) What studies would you perform on the defective camera to be least disruptive to the day
A

a) Regular maintenance and QC

b) 1. Urgent/Emergent cases
2. Inpatients
3. Patients who have travelled from out of town

c) - Studies that are unlikely to need SPECT
- Studies that don’t require both anterior and posterior views
Eg. Renogram, thyroid imaging

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21
Q

Patient just received subcutaneous injection. Fever, dyspneic, systolic blood pressure 95, heart rate 110 (and rash?).

a)What is happening (0.5 marks)

List 2 of your first actions to take

A

a) anaphylactic shock

b) Call a code
Assess ABCs and Get IV access
Maybe give an intramuscular dose of epi (.3-.5 ml 1:1000 in lateral thigh) while obtaining IV access.

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22
Q

List the medication and adult doses that could be used for the following situations: (A)Antidote for dipyridamole. (B) Cerebral perfusion reserve. (C) Hydronephrotic collecting system on renography.

A
  • Aminophylline 100-200 mg IV
    • Acetazolamide 1000 mg IV
    • Furosemide 40 mg IV
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23
Q

A Nuclear Medicine technologist tells you that a patient has shown up, referred for a bone scan to rule out a metatarsal stress fracture, but the patient thinks she may be pregnant (last period was 4 weeks ago). Do you proceed with the scan? Give reasons.

A

No, get a pregnancy test first. Especially considering the study is not an emergency. Can consider doing MRI.

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24
Q

6 absolute contraindication to cardiac stress

A

Absolute:

  1. Acute MI (<4d)
  2. Acute PE
  3. Acute dissection
  4. Acute myocarditis/pericarditis
  5. Severe pulm hypertension
  6. Severe angina (high risk/unstable)
  7. Severe CHF (decompensated or poorly controlled)
  8. Severe HTN (200/110 mmHg)

Relative:

  1. Known LM disease
  2. Moderate AS
  3. Outflow tract obstrution
  4. Arrhythmia
  5. High degree AV block
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25
Q

6 contraindications (relative or absolute ) to dipyridamole

A

Absolute:
1. Asthma with ongoing wheezing (if mild, can pretreat with two puffs of albuterol or a comparable inhaler)
2. 2nd/3rd degree AV block without pacemaker
3. Systolic BP < 90
4. Known hypersensitivity
5. Recent xanthine
+ ones from above

Relative:
1. Profound sinus bradycardia (< 40 bpm)

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26
Q

What are the mechanisms of action of dipyridamole and adenosine?

A

a. Dipyridamole: Indirectly inhibits the metabolism of adenosine by blocking adenosine deaminase and phosphodiesterase.
b. Adenosine readily diffuses into extracellular space, where it acts on coronary endothelial cells’ A2A receptors, causing vasodilation. It also acts on A1 receptor subtypes (causing AV heart block), and on A2B & A3 receptor subtypes (causing bronchospasm).

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27
Q

Apical hypertrophic cardiomyopathy
a) EKG findings?

b) MPI findings?
A

a) Typical finding is giant (>10 mm) inverted T waves in the anterolateral leads

b) Increased apical tracer uptake, ‘spade-like’ deformity of the left ventricle, ‘Solar Polar’ map pattern
Stress: relative apical ischemia (reduced apical flow reserve)

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28
Q

Name 2 complications of Kawasaki disease.

A

a. Coronary artery aneurysms
b. Valvular disease
c. Aortic aneurysms
d. Intestinal ischemia and obstruction
e. Uveitis and conjunctival hemorrhage
f. Cerebral ischemia and infarct

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29
Q

What is Takotsubo cardiomyopathy?

A

Transient systolic dysfunction of the LV in the absence of obstructive CAD. Most commonly there is ballooning of the LV apex, and it most commonly occurs in women exposed to sudden emotional or physical stress.

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30
Q

What are 4 advantages of thallium in myocardium perfusion imaging.

A
  • Redistribution from single injection
  • Viability
  • Better target to background
  • highest myocardial extraction coefficient (85%)
  • peak myocardial concentration at 10 minutes after injection (image earlier)
  • Longest shelf life
  • Cheaper
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31
Q

Which segment model is standard according to some (?) cardiac paper? What is SDS and how is it calculated? ( I think they also asked importance of SDS?)

A

17 segment model.
Sum difference score. SSS-SRS=SDS

Many investigators consider a SSS < 4 a negative exam [146]. A SSS of 4-8 is associated with an event rate of 1-3% [144]. More extensive and severe abnormalities, encumbering 10% of more of the myocardium, are associated with up to 5% annual cardiac event rates. Patients with less than 10% ischemic myocardium are candidates for an initial strategy of intensive medical and lifestyle intervention with deferred revascularization.

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32
Q

4 or 5 high risk prognosticators on cardiac nuc study.

A

1- Multiple perfusion defects in more than one coronary artery distribution- reflective of multivessel disease

2- Single large perfusion defect. PCI fails to offer any prognostic benefit over optimal medical therapy, unless a significant amount (generally more than 10%) of the LV myocardium is ischemic [80].

3- TID

4- Post stress LVEF < 40%

5- Increased lung activity on post stress imaging (>0.5 thallium, >0.4 sestamibi/tetrofosmin)

6- Increased end-systolic volume (greater than 70 mL)

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33
Q

Define TID? What is the cause?

A

Transient Ischemic DIlatation.

TID is considered to represent severe and extensive subendocardial ischemia and has been shown to be highly specific for critical stenoses in vessels that supply a large portion of the myocardium (ie, proximal left anterior descending/left main or multivessel lesions (90% stenosis). Implies that disease is more extensive than the (sum of the) focal defects alone.

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34
Q

You read a MIBI scan that shows mild to moderately severe ischemia involving the entire inferior wall. The EF is normal. The patient is asymptomatic, is not on any medications, does not have known coronary artery disease, has a normal ECG and no risk factors. According to the Courage trial, what would you recommend as the most appropriate next step? The family physician contacts you and asks whether PCI would reduce his chances of myocardial infarction and death?

A

Next step
o Assuming that I am satisfied that the inferior wall defect is not due to attenuation artifact, since
the patient is asymptomatic, I would recommend conservative medical management as the first
step
Benefit?
o No significant difference between conservative best medical management and PTCA/PCI for
mortality

The COURAGE trial (reported in NEJM 2007): Optimization of medical therapy alone without PCI is sufficient for initial treatment of patients with stable coronary artery disease. The addition of PCI to optimal medical therapy does not improve mortality or cardiovascular outcomes as evidenced by the COURAGE trial, and given its risks as an invasive procedure, should not be offered as initial treatment strategy for this patient population.

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35
Q

A fixed perfusion defect is seen on a MIBI SPECT study. What are 3 ways to differentiate attenuation artifact from a true defect?

A
  1. cine data for motion artifact and attenuation
  2. Review attenuation corrected images
  3. Perform prone imaging, which separates the subdiaphragmatic structures further from the heart and
    can reduce attenuation artifact
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36
Q

What is the length of each stage in a Bruce protocol stress test? After completing 1 stage in a Bruce protocol stress test, how many METS will the patient have achieved?

A
  • Length: 3 minutes

* METS: 4.6

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37
Q

4 causes of decreased PFR (peak filling rate) on MUGA (peak filling rate)

A 
Coronary artery disease
CHF
Cardiomyopathies
Aortic valve disease
Rejection post cardiac transplant
Normal aging
HTN
LVH due to aortic stenosis
mitral stenosis
Medications: e.g., doxorubicin, nitro, beta blockers
Pericardial disease

Diastolic function assessment. The lower normal limit of PFR is 2.50 end diastolic volume per second (EDV/s).

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38
Q

Describe 3 methods to prepare a patient for cardiac viability study using FDG-PET.

A
  1. Oral glucose load
    o 50-100 g glucose po 1-2h before exam
    o In a diabetic check serum glucose and administer insulin per sliding scale
2. Hyperinsulinemia euglycemic clamp
o Start 2 IV’s
o Run insulin 100 mIU/kg/h in one IV
o Run glucose (20% in 500 ml) + KCl (20 ml of 15%) solution in second IV
o Adjust to maintain euglycemia
  1. Nicotinic acid derivatives
    o Acimipox 250 mg
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39
Q

a) List 4 imaging patterns for cardiac perfusion and FDG

b) Give most typical cause for each of the FDG patterns

A

Pattern Perfusion FDG metabolism

Normal Present Present

Ischemic Absent or decreased Present

Infarcted Absent Absent

Hibernating Decreased Normal or increased

Stunned Present Present

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40
Q

Indications for cardiac PET

A

•A) prior stress imaging study of poor quality or inconclusive

•B) body characteristics affecting image quality
–Obesity, large breasts/implants, pleural effusion

•C) High-risk patients
–Chronic kidney disease, DM, CABG, suspected LM or 3VD

•D) Young patients with established CAD
–To decrease radiation

•E) If myocardial blood flow quantification is desired

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41
Q

Fixed stress and 4 hr delayed thallium defect (give 2 non artifactual causes, and 2 pet tracers to differentiate it.

A

Causes: Infarct vs hibernating myocardium (Thallium not 100% sensitive/specific)

FDG or C11-palmitate or C11-acetate for viability

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42
Q

4 causes for reversed mismatch perfusion and FDG.

A

Reverse mismatch pattern denotes normal perfusion with relatively reduced metabolism.

○	non-ischemic cardiomyopathy
	○	LBBB
	○	repetitive stunning
	○	following revascularization early post-MI when the myocardium is stunned
	○	in some patients with diabetes
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43
Q

In hibernating myocardium, what is type of metabolism is the main source of energy? In the fasting state, what is the usual substrate for normal myocardium? What is observed on an FDG-PET study in hibernating myocardium.

A

• Hibernating: glycolytic
• Fasting: fatty acids
• What is observed in hibernating:
o Preserved uptake on FDG-PET imaging (perfusion-metabolism mismatch)

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44
Q

Name 3 causes of cardiac uptake on pyrophosphate scan.

A 
Acute MI
Unstable angina
Valvular calcification (very focal)
Resuscitation / cardioversion
Myocarditis / pericarditis
Amyloidosis
Cardiomyopathy
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45
Q

What does heparin do in cardiac imaging

A

IV unfractionated heparin activates lipoprotein and hepatic lipases, thereby increasing plasma free fatty acid levels, and ultimately causing a reduction in glucose consumption of normal myocytes. Doses as high as 50 IU/Kg were used in prior studies.

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46
Q

Rpt 23: What energy sources (plural) does heart use

A

a) typically? Free fatty acids(major), Glucose
b) in fasting conditions? Free fatty acids
c) in carbohydrate-rich conditions? Glucose

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47
Q

Regarding hibernating myocardium:

A

a. What is metabolic substrate of hibernating myocardium? Glucose
b. What is metabolic substrate of normal myocardium? Fatty acids

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48
Q

Name 4 contraindications to atropine.

A
  1. Narrow angle glaucoma
  2. Obstructive uropathy
  3. A-fib with uncontrolled HR
  4. Obstructive GI disease or paralytic ileus
  5. Known hypersensitivity
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49
Q

Name 2 surgical procedures that would be performed in a repair for transposition of the great arteries.

A

a. Historical: Senning and Mustard

b. Today: Jatene

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50
Q

Patient is mildly hypocalcemic and has mild elevation of parathyroid hormone. What is cause of increased PTH? What will the scan look like (which scan are they talking about)?

A

Secondary hyperparathyroidism due to chronic renal disease.
Sestamibi: will be negative for parathyroid adenoma
Bone scan: can have metabolic superscan
Overproduction of parathyroid hormone occurs in response to hyperphosphatemia, hypocalcemia, and impaired 1,25-dihydroxyvitamin D production by the diseased kidneys.

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51
Q

3 ways parathyroid functions in the body

A
  1. Promotes bone resorption by osteoclasts
  2. Calcium absorption in bowel via vit D
  3. Calcium resorption in the renal tubules
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52
Q

Parathyroid imaging: up to how many parathyroid glands can one have, and what is the typical number? Where can ectopic parathyroid glands lie? The technologist informs you that instead of Tc-MIBI, Tc-Tetrofosmin was delivered instead. Can you use this instead?

A

How many: up to 6-7, typically 4

Ectopic locations
- Typically along the thyrothymic tract, most commonly in the anterior mediastinum, although
can be anywhere from high cervical to inferior to the heart
- Can lie anywhere along the migratory paths of the 3rd and 4th branchial pouches; from the cricothyroid cartilage superiorly to the tracheal carina inferiorly.

Literature indicates no, tetrofosmin inferior to sestamibi

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53
Q

Describe 3 types of Hyperparathyroidism.

A
  1. Primary - hyperfunction of glands themselves. There is oversecretion of PTH due to a parathyroid adenoma, parathyroid hyperplasia or, rarely, a parathyroid carcinoma. This disease is often characterized by the quartet stones, bones, groans, and psychic overtones referring to the presence of kidney stones, hypercalcemia, constipation and peptic ulcers, as well as depression, respectively
  2. Secondary - physiological (i.e. appropriate) secretion of parathyroid hormone (PTH) by the parathyroid glands in response to hypocalcemia (low blood calcium levels). The most common causes are vitamin D deficiency (caused by lack of sunlight, diet or malabsorption) and chronic kidney failure.
  3. Tertiary - long-term secondary hyperparathyroidism which eventually leads to hyperplasia of the parathyroid glands and a loss of response to serum calcium levels. This disorder is most often seen in patients with chronic renal failure and is an autonomous activity.
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54
Q

For a parathyroid scan, what is the difference between a dual phase vs. a dual isotope study?

A

o A dual phase scan relies upon differential washout characteristics between thyroid tissue and
parathyroid tissue at early and late time points with sestamibi (i.e., thyroid washes out,
parathyroid does not)

o A dual isotope study compares or subtracts a thyroid uptake scan (pertechnetate or 123I) from a
sestamibi study, to determine what constitutes parathyroid uptake

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55
Q

Thyroid surgeon to take out thyroid and do central compartment clearance. What are the anatomical boundaries of central compartment?

A

Hyoid bone (superior)
Carotid arteries (laterally)
Superficial layer of deep cervical fascia (anteriorly)
Deep layer of deep cervical fascia (posteriorly)
Innominate artery on right and corresponding axial plane on left (inferior)

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56
Q

List mechanism of PTU and methimazole

A

PTU: Affects thyroid peroxidase therefore decreases oxidation/iodination/coupling, Non-competitive inhibitor for T4 to T3 conversion

Methimazole: Affects thyroid peroxidase therefore decreases oxidation/iodination/coupling

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57
Q

List 4-5 reasons for increased RAIU, excluding hyperthyroidism (Graves) and iodine deficiency

A
  1. TSH-secreting pituitary adenoma
  2. Early Hashimoto’s thyroiditis
  3. Rebound after subacute thyroiditis
  4. Rebound after thyroid hormone withdrawal
  5. Lithium
  6. Pregnancy
  7. Medications – overtreatment with PTU
  8. Dyshormonogenesis (decompensated)
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58
Q

What is a discordant nodule?

A

A discordant nodule is hot on Tc-99m images, but cold on the I-123 exam. Discordant nodules can be explained by either the preservation of Tc-pertechnetate trapping, but failure of organification or the rapid release of organified iodine from the nodule (iodine has washed out of gland by time of scanning at 24 hours)

Solitary discordant thyroid nodules are generally considered to be rare (2 to 8%) and cases of discrepancy between the Tc-99m and I-123 studies appear most often in multinodular goiters [6,17]. Discrepancies are also far more likely to be caused by benign thyroid disorders rather than malignancy

A conservative approach to this problem would be to re-scan any patient with a hot nodule on the Tc-99m pertechnetate exam with I-123. However, the risk of cancer in a nodule appearing hot with Tc-99m and cold with radioiodine is probably so low that routine reimaging is not necessary

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59
Q

List 5 high risk thyroid cancer pathologies or cell types

A

Anaplastic, medullary, Tall cell, Hurthle, follicular

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60
Q

Papillary thyroid cancer. Thyroglobulin remains high post-surgery. What measurement do you use for 2 sequential thyroglobulin?

A

Thyroglobulin doubling time (< 1 year, 1-3 years and > 3 years all different prognoses)

b) What prognosis does it indicate?
Increased chance of death

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61
Q

Thyroid cancer

a) List 2 cell types of thyroid cells (2 marks)
b) List cancers associated with these cell types and biochemical markers (2 marks)

A

a) Follicular and C (parafollicular) cell

b) Papillary and follicular – thyroglobulin
Medullary – calcitonin and CEA

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62
Q

Radioiodine treatment for hyperthyroidism. How long to stop medications?

A

b) thioamides (PTU and methimazole) – 3 days
e) iodine-containing multivitamins 7-10 days
c) Lugol’s 2-3 weeks
d) CT contrast 6-8 weeks
a) amiodarone – 3-6 months

f) SSKI 2-3 weeks

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63
Q

What is the role of lithium in thyroid cancer treatment? What is a condition in which it could be used?

A

Combining with radioiodine in the treatment of metastatic radioiodine resistant thyroid cancer (increases radioiodine uptake).

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64
Q

2 causes of thyrotoxicosis and decreased RAIU

A
  1. Thyroiditis
  2. Iodinated contrast
  3. Exogeneous
    a) Facticious hyperthyroidism
    b) Exogeneous thyroid hormone in food/medication
  4. Ectopic
    a) struma ovarii
    b) follicular thyroid CA with functioning mets
  5. Jod-Basedow
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65
Q

Name 4 causes of absent or low uptake of the thyroid on thyroid scan.

A
  1. Thyroidectomy
  2. Thyroiditis
  3. Iodinated contrast
  4. Iodine rich diet
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66
Q

Name 4 medications that can decrease RAIU.

A
  1. PTU
  2. Methimazole
  3. Iodinated contrast
  4. Amiodarone
  5. Synthroid
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67
Q

.What is the reason for doing perchlorate washout test?

A

To identify thyroid iodine organification defects

in patients with defects in peroxidase activity (usually hypothyoid), trapped radioiodine is rapidly discharged when sodium perchlorate (an inhibitor of thyroid iodide trapping) is administered.
Thyroid uptake is then determined between 2 and 4 hours after administration of the dose. Potassium perchlorate 109 mg/kg is then administered orally and a repeat measurement of RAIU performed in 30 to 60 minutes. A decrease in RAIU greater than 10-15% following perchlorate administration is indicative of any organification defect.

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68
Q

When do you stop methimazole before treatment and when to re-start.

A

SEE NOTES FOR STOPPAGE TIMES

Can be restarted 2-3 days after therapy.

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69
Q

4 clinical risk factors for thyroid cancer.

A
  1. Hx of childhood head and neck radiation.
  2. Total body irradiation for bone marrow transplant.
  3. Family history 1st degree relative.
  4. Cowden’s, FAP, Carney complex, MEN2.
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70
Q

. 2 reasons to image congenital hypothyroidism.

A

It can be transient (maternal antibodies or maternal meds) or permanent.
Aplasia, hypoplasia/ectopic thyroid or dyshormonogenesis.
Image to differentiate anatomical causes from functional causes.

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71
Q

List 6 causes for focal uptake on FDG-PET in thyroid gland.

A
  • Thyroid adenoma
    • Thyroid malignancy (e.g., papillary or follicular carcinoma)
    • Thyroid abscess
    • Thyroid hematoma
    • Thyroid lymphoma
    • Intrathyroidal parathyroid lesions (e.g., parathyroid adenoma, parathyroid carcinoma)
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72
Q

What are 3 causes of jaundice in an infant.

A 
Biliary atresia
Neonatal hepatitis
Sepsis/TORCH infection
Breast feeding/breast milk
Choledochal cyst
Alagile syndrome
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73
Q

List 4 clinical/laboratory/pathology (non-imaging) findings that may differentiate between biliary atresia and hepatitis.

A

Onset - earlier onset of jaundice and of acholic stools in biliary atresia compared with those who have neonatal hepatitis.

Associated abnormalities – congenital heart disease and polysplenia syndromes associated with biliary atresia.

GGT – usually elevated in biliary atresia; if low or normal should look for other diagnosis

Patient demographics - Neonatal hepatitis – more common among males, especially low birth weight or preterm; biliary atresia - more common in females of normal weight

Liver biopsy – can look for obstructive vs. non-obstructive features

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74
Q

What tracer is used for biliary atresia versus hepatitis? What is interpretation criteria for each? What is the dose and time of the pre-medication given.

A

Tcc99m – mebrofenin 1mCi IV
Mebrofenin recommended over other IDA agents because of better hepatic excretion.
Standard dose of 1mCi is given because of the potential need for 24hr imaging and the decay of Tc99m at 24hrs (normal max IDA dose is 0.5mCi)

Pharmacologic enhancement with phenobarbitol: 2.5mg/kg po bid x 5 days:
o phenobarbitol enhances hepatic excretion of the tracer, which should allow earlier visualization of excretion into the bowl → this is an issue because we are imaging with Tc99m, which decays significantly by the time we get to doing 24hr images

Lack of biliary excretion into the bowel at 24 hrs
o Image first at 1hr, return in 4hrs and 24hrs to confirm
o not diagnostic of biliary atresia, but supportive of the diagnosis
o False +ves:
▪ Immature intrahepatic transport mechanisms
▪ Severe intrahepatic cholestatsis (alagille’s syndrome)

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75
Q

What is a Kasai procedure. What is a Kasai procedure used to treat?

A

Portoenterostomy: to bypass atretic biliary duct

Used to treat biliary atresia

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76
Q

List 4(6) actions of CCK

A

Moving a bolus into stomach and another bolus out of stomach.

  • relax LES
  • increase pyloric tone
  • decrease gastric motility
  • increase pancreatic secretions
  • increase gall bladder contraction
  • increase small bowel motility
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77
Q

6 causes of non vis of GB after 1 hr of hida study (excluding acute cholecystitis and chronic cholecystitis)

A 
Prolonged fast (resulting in gall bladder filled with bile)
Complete common duct obstruction
Postcholecystectomy
Acute pancreatitis
Nonfasting normals
Severe hepatocellular disease
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78
Q

Name 2 advantages of using a longer (60 minute) rather than a short (3 minute) infusion for Sincalide. List 4 clinical conditions (not medications) that cause decreased gallbladder contraction.

A

2 advantages
o Longer infusion is more physiologic and results in fewer symptoms
o Largest study to date using 60 minute infusion found less variability in gallbladder ejection fraction

4 causes
o Chronic acalculous cholecystitis
o Sphincter of Oddi syndrome
o Biliary dyskinesia
o Cystic duct syndrome
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79
Q

List one effect and one use of the following agents in hepatobiliary scintigraphy: CCK, morphine, phenobarbital

A

CCK:
o Induces gallbladder contraction
o Can be used to evaluate gallbladder ejection fraction

Morphine:
o Causes sphincter of Oddi contraction
o Can be used to reduce time of hepatobiliary scintigraphy for acute cholecystitis if have nonvisualization of GB at 30-60 min

Phenobarbital:
o Induces hepatic enzymes and improves uptake
o ↑ specificity of hepatobiliary scintigraphy for biliary atresia

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80
Q

Name 3 lesions that show uptake on a hepatobiliary scan.

A

Hepatocellular carcinoma
Focal nodular hyperplasia
Hepatic adenoma

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81
Q

How to detect aspiration post feeds in a child?

A

Radionuclide Salivagram

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82
Q

List 4 medications or classes of medications that decrease gastric emptying

A 
Drugs that increase motility
o erythromycin
o metoclopramide
o domperidone
o cisapride
o tegaserod
o thyroxine
Drugs which delay motility
o opiates
o antispasmodic agents (anticholinergic)
o atropine
o nifedipine
o progesterone
o octreotide
o theophylline
o benzodiazepine
o phentolamine

Conditions that change gastric emptying:
o Increased gastric emptying: Gastritis, Hyperthyroidism

o Decreased gastric emptying: Anorexia, fatty meal, protein meal, hypothyroidism

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83
Q

List amount and quantities of meal for gastric emptying as per SNM

A 
meal eaten within 10 minutes
▪        4oz liquid egg white
▪        2 slices white toast
▪        30g jam
▪        120mL water
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84
Q

Describe the meals used for liquid and solid gastric emptying.

A

Solid: 0.5-1.0mCi 99m-Tc Sulfur Colloid, 4oz. egg white equivalent, 2 slices white toast, 30g strawberry jam, 120 cc H20, consumed within 10 minutes

Liquid: Not as sensitive a test for delayed emptying as solid. Can use any liquid. Ensure used locally.

  • Solid gastric emptying has three phases in the stomach, accommodation, trituration and emptying, and the last phase is linear. The liquid emptying does not require trituration, and it is exponential
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85
Q

Name a tracer being investigated for congenital hyperinsulinism.

A
  • F-18 DOPA PET/CT
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86
Q

Urea breath test
a) Urease. What happens to 14C-urea. (What are products of urease?)

b) Explain reason for achlorhyrdia causing positive test

A

a) 14C urea is hydrolyzed into ammonia and 14CO2 in the presence of urease
b) Achlorhydria (absence of hydrochloric acid in gastric secretions) can cause overgrowth of non-H.Pylori bacteria (resulting in a false positive)

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87
Q

How does partial gastrectomy lead to a false positive urea breath test?

A

Potential resultant bacterial overgrowth (achlorhydria) with resultant non-H. pylori urease

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88
Q

In a C-14 urea breath test, what is the bacterial enzyme responsible for degrading the urea? What two components is the urea degraded to in the stomach?

List 2 causes of false positive C-14 urea breath tests.

List 3 classes of medications that can cause false negative C-14 urea breath test.

A

Enzyme: urease

Two components: NH3 and 14CO2

False positives
o Chewing capsule
o Chemiluminescence
- achlorhydria

False negative medications
o Antibiotics
o Proton pump inhibitor
o Bismuth

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89
Q

What does aminopyrine test measure?

A

The 14C-Aminopyrine Breath Test provides quantitative assessment of liver function in conditions such as established chronic hepatitis and cirrhosis.

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90
Q

Name 2 causes of focal decreased activity on a liver sulfur colloid scan.

A

CYST, METASTASIS, HEPATOMA, HEMATOMA, ABSCESS, HEMANGIOMA

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91
Q

Name 2 causes of focal increased activity on a liver sulfur colloid scan.

List 3 reasons for liver hot spots/ increased live activity on sulfur colloid.

A
  1. FNH
  2. Regenerating nodule of cirrhosis
  3. Budd Chiari
  4. SVC obstruction
92
Q

Name 3 causes of diffuse lung uptake on sulphur colloid imaging.

A
  1. Al3+ ion in generator eluate (causing flocculation)
  2. Medications containing aluminum (e.g., antacids)
  3. Boiling radiopharmaceutical preparation for too long, resulting in too large particles
93
Q

What is the lowest bleeding rate detectable by radionuclide techniques?

A
  1. Tc-99m SC 0.05-0.1cc/min
  2. Tc-99m RBC scan 0.1cc/min
  3. Angiography 0.5-1.0cc/min
94
Q

What are 3 medications used to prepare a patient for Meckel scan.

A
  1. H2 Blockers: H2 receptor antagonist, decreases excretion, so that pertechnetate is trapped in areas of ectopic gastric mucosa
    Cimetidine 300 mg PO qid 2 days before study (10-20 mg/kg in children); OR
    Ranitidine 1mg/kg IV over 20 min, 1 hr before test
  2. Pentagastrin (Pentavlon): ↑ uptake and excretion by ectopic gastric mucosa
    Pentagastrin 6 ug/kg SC 5-15 min before study
  3. Glucagon: Used with Pentagastrin; ↓ GI motility to prevent excreted pertechnetate migrating from area of ectopic gastric mucosa. Following the I.V. administration of glucagon peak activity occurs between 2 to 4 minutes and last for 10 to 17 minutes [1].
    Glucagon 50 ug/kg IV 10 min before study
95
Q

What is the incidence of Meckel’s? What proportion of Meckel’s diverticula have ectopic gastric mucosa? Which gender if more affected and by how much?

A

Incidence: many textbooks say 2%
Proportion with ectopic gastric mucosa: 20-40%
Gender: male (3-5:1) No gender predilection in incidence of diverticula, but boys are 3-4x more likely to develop complications.

96
Q

4 factors that increase accuracy of quantitation of gastric emptying study.

A

Adhered to overnight fast before procedure and abstained from caffeine or smoking
Held meds known to interfere with gastric emptying
Patient ate the standard meal within 10 minutes
No nausea or vomiting after meal ingestion
No gastroesophageal reflux
No bowel activity overlapping with stomach ROI
Decay correction of tracer used

97
Q

Name 2 false positives for Meckel and 2 false negatives.

A

False positive

  1. Any cause of focal hyperemia: Hemangioma (usually multiple), AVM, Vascular tumor
  2. Duplication cyst containing gastric mucosa
  3. Intussusception
  4. Inflammation: Appendicitis/Abscess/IBD
  5. Renal pelvis or collecting system activity

False negative

  1. Small amount of ectopic gastric mucosa - < 2cm^2
  2. Uptake in Meckel’s diverticulum obscured by overlying activity (urine, bladder)
  3. Uptake obscured by barium from prior study
98
Q

a) What is 75SeHCAT?

b) Describe imaging

A

a) Taurine-conjugated bile acid analog which is used to investigate for possible bile salt malabsorption in patients with diarrhea

b) Oral capsule (10 μCi = 370 kBq)
Uncollimated gamma camera
Image head to thigh, 1-3 h after ingestion
Repeat scan at 7 days
Retention >15% normal
Retention <15% abnormal, suggest bile acid malabsorption

99
Q

List the 3 most commonly used renal tracers. For each, list their main mechanism of excretion/action. Which renal agent may bind poorly to the renal cortex in the setting of renal tubular acidosis?

A

TC-DTPA – glomerular filtration

TC-MAG3 - proximal renal tubule (tubular secretion)

TC-DMSA – eliminated by the glomerulus and tubular secretion; binds to prox tubule (affected by RTA)

100
Q

You are evaluating a 2 week old infant being evaluated for prenatal hydronephrosis. What are 4 false positives for obstruction?

A
  1. Inadequate Lasix response (renal failure, paediatrics, dehydration)
  2. Functional obstruction (can be postural, dilated collecting system)
  3. Technical issues (high background or cortical retention)
  4. Large, flaccid, compliant renal pelvis or ureter
  5. Interstitial injection of lasix
  6. Overdistension of bladder
101
Q

2 reasons DMSA show a defect. One complication of severe reflux in children.

A

Reasons:

  1. Pylonephritis
  2. Scar
  3. Cyst
  4. Mass

Complication:
Scarring, HTN, infection

102
Q

List 5 causes of error in GFR determination using radionuclide techniques (5 marks)

A

Camera based:

  1. Background correction
  2. AC
  3. System dead time
  4. Radiopharmaceutical quality
  5. Estimation of arterial plasma activity

Plasma sample based:

  1. Interstitial injection
  2. RP quality
  3. Handling blood samples
  4. Wrong time for plasma collection

Common to both:

  1. Patient hydration
  2. Free technetium
  3. Interstitial injection
  4. Meds (aluminum)
  5. CHF
103
Q

Name 2 contraindications for GFR calculation that affect the volume of distribution.

A
  1. Hyperhydration
  2. 3rd spacing - edema, fluid collection-> delays mixing of tracer through its distribution volume, results in overestimated GFR
104
Q

Name 3 features of a high probability study for renovascular hypertension.

A
  1. Unilateral parenchymal retention after ACEI is the most important criterion for 99mTc-MAG3 and 123I-OIH
  2. Change in the renogram grade
  3. Prolongation of the transit time
  4. Decrease in relative uptake by 10%
105
Q

What is the most common cause of hypertension?

A

Essential hypertension

106
Q

Name 2 causes of renovascular hypertension.

A

Atherosclerosis
Fibromuscular dysplasia
Systemic vasculitis
Renin-secreting renal tumor

107
Q

List 5 (or 6?) clinical findings that may suggest renovascular hypertension

A
  1. Abrupt or severe HTN (diastolic BP > 120 mm Hg
  2. HTN resistant to medical therapy
  3. HTN with onset in patients < 30 yo or > 55 yo
  4. Abdominal or flank bruits
  5. Worsening renal function during ACE inhibitor therapy
  6. Patients with occlusive vascular disease in other vascular beds
108
Q

3 patient prep steps for captopril studies.

A
  1. Discontinue all ACEI 2-3 days for captopril and 5-7 days for enalapril/lisinopril
  2. Stop ARBS and Ca channel blockers. Also stop diuretics
  3. No solid food 4 hours prior to exam.
  4. Be well hydrated.
109
Q

List 3 advantages of RNC over VCUG

A
  1. At least and probably more sensitive than VCUG
  2. Gonadal dose is about 1/100 of VCUG
  3. High temporal resolution/allows for continuous monitoring
  4. Overlying bowel contents not a factor
110
Q

According to the SNMMI guidelines, what are the 3 grades of reflux that should be used in radionuclide cystography, what do they represent? What is the smallest amount of reflux that can be detected by radionuclide cystography?

A

a. 3 grades:
i. Grade I: mild = reflux within ureter
ii. Grade II: moderate = reflux into renal collecting system
iii. Grade III: severe = dilation of collecting system and dilated/tortuous ureter
b. Smallest amount detectable: 0.2 cc

111
Q

Post-renal transplant. Still anuric at 24 hours. List 3 possible reasons

A

Hyperacute rejection
ATN
Ureteric obstruction
Renal artery thrombosis

112
Q

Non radioactive tracer for GFR, most common nucs tracer for GFR.

A

Inulin

Tc-99m-DTPA

113
Q

What is the most common organism in malignant otitis externa?

What is the underlying condition that predisposes to this entity?

A

a) Pseudomonas aeruginosa

b) Diabetes

114
Q

Name 2 causes of non-infectious focal and diffuse increased activity on a In111-WBC scan.

A

Infection:
● Opportunistic infections such as pneumocystis carinii pneumonia, CMV pneumonitis, or Mycobacterium avium-intracellulare

Non-infectious:
● Congestive heart failure
● Adult respiratory distress syndrome: Due to increased permeability of the alveolar-capillary membrane resulting in migration of leukocytes into the lung parenchyma [34].
● Drug induced pneumonitis: Induces an intense neutrophilic reaction in the lungs
● Aspiration
● Following XRT
● Following cardiopulmonary resuscitation
● Following hemodialysis: Complement activation after hemodialysis results in increased pulmonary sequestration of leukocytes [34].

115
Q

Name 2 causes of diffuse lung activity on a Ga67 scan.

A 
Other disorders which can result in diffuse pulmonary accumulation of Gallium include:
●       Lymphangitic carcinomatosis
●       Pneumoconiosis/Silicosis
●       Idiopathic Pulmonary Fibrosis
●   	Acute Radiation Pneumonitis
116
Q

Inflammatory imaging. List mechanisms of localization or uptake for:

a) WBCs
b) MDP
c) FDG
d) Ga

A

a) WBCs – chemotaxis to sites of infection/inflammation
b) MDP – chemiabsorption on hydroxyapatite in sites of increased bone turnover
c) FDG – facilitated diffusion of FDG as glucose analog for aerobic metabolism.
d) Ga – attachment to transferrin, lactoferrin, bacterial siderophore, increased flow and macrophage phagocytosis

117
Q

Name the most frequent cause of a false positive on In111 WBC scan performed for IBD.

A

labeled cells sloughed from sites of active inflammation can be carried distally causing the appearance of pan-colitis, multiple sites of bowel inflammation, etc.

118
Q

3 radiotracers to image FUO?

A

Gallium-67, Indium-111 WBC, FDG

119
Q

Which tracer is best for toxo versus lymphoma?

A

Thallium 201 is +ve in Lymphoma but –ve in Toxoplasmosis

vs. FDG

120
Q

Gallium forms in circulation and their biodistribution? 3 causes for increased bone uptake on gallium.

A

Gallium:

a) bound to the plasma protein transferrin (iron binding protein)
b) it accumulates in leukocytes by binding lactoferrin
c) taken up by bacteria into siderophores (iron scavengers)

Causes
●	Transfusions (increased Fe pool saturates iron receptors and increases bone and GU activity)
	●	Gadolinium
	●	Cytotoxic drugs (cisplatin)
	●	Infection
	●	Violated bone (surgery or #)
121
Q

How do the following things affect a gallium scan? Gold therapy in patient treated for juvenile rheumatoid arthritis, furosemide, (bleomycin, busulphan, nitrofurantoin), vincristine, cisplatin, amiodarone.

A

Gold therapy - Decreased hepatic uptake; increased lung uptake

Amiodorone - Increased lung uptake often related to pneumonitis

Furosemide - drug induced interstitial nephritis; delayed and increased renal uptake

Cytotoxic drugs - cisplatin, methotrexate -> decreased tumour and hepatic uptake; increased skeletal adn renal

122
Q

4 reasons for cold defect on WBC images?

A
  1. Attenuation from hardware, barium, external objects.
    1. Encapsulated nonpyogenic abscess.
    2. Vertebral osteomyelitis.
    3. Chronic low-grade infection.
    4. Parasites, mycobacteria, fungal infection.
    5. Infarct
123
Q

3 features of fever of unknown origin?

A

Fever
higher than 38.3 °C
for at least 3 weeks,
without Dx after aggressive investigation in hospital for 3 days or 3 outpatient visits.

124
Q

2 tracers that can be used for WBC imaging.

A

111In oxine

99mTc-HMPAO

125
Q

How much blood do you collect for WBC imaging? What is needle size allowed?

A

40-50 ml.; 19-gauge needle

126
Q

In the setting of inflammatory disease, list the mechanism for localization with each of the following radiotracers: FDG? MDP? Tc or In-WBC? Ga?

A

FDG: Activated leukocytes in areas of inflammation have elevated GLUT-1 expression and higher glucose metabolism, which ↑uptake

MDP: In areas of increased osteoblastic activity. Phosphonate compounds bind to Ca2+ in bone (chemisorption). They are then exchanged for calcium phosphate in new bone matrix.

Tc/In-WBC: Labeled leukocytes undergo chemotaxis to areas of inflammation in response to cytokine gradient

Ga: Multiple mechanisms:
▪ Gallium bound to transferring in plasma
- Activated neutrophils in areas of inflammation secrete lactoferrin, which has a higher binding affinity for Ga than transferrin in plasma; therefore get transchelation from Ga-transferrin to Ga-lactoferrin
- Increased capillary permeability and hyperemia in areas of inflammation causes ↑Ga uptake
▪ B lymphocytes and other leukocytes may express transferrin receptor, which binds Ga-transferrin complex
▪ Phagocytes may internalize Ga-protein complexes into siderophores

127
Q

Most common age group for osteosarcoma? 2 most common met sites? Most common bones involved? Within a long bone which is most common place?

A

a. Most common age range: 10-30 then 60+
b. Most common sites of metastasis: lung, skip lesions to bone
c. Most common primary: metaphysis of long bones (femur, tibia, humeri), then verterbrae
d. Clinical presentation: pain and soft tissue swelling

128
Q

Paget’s
a) Appearance on bone scan/ What are the 3 phases and degree of uptake in each?

b) Characteristic findings in long bones (What feature in long bones differentiate Paget from other entities?)
A

o lytic phase – increased uptake
o mixed phase – increased uptake
o sclerotic phase – mild to normal uptake

The most commonly involved bones:
o   vertebral bodies (30-75%)
o   pelvis (30-75%)
o   skull (25-65%)
o   proximal long bones (25-30%)

Begins in the epiphysis and extends along the diaphysis of long bones in a characteristic wedge-shaped (“flame” or “blade of grass”) appearance

129
Q

How do following drugs affect a bone scan? Nifedipine, dextrose, corticosteroids, vincristine, doxorubicin, estrogen, iron dextran.

A
  1. nifedipine (Ca channel blocker) - decreased bone uptake
  2. corticosteroid - decreased bone uptake
  3. dextrose - increased renal activity
  4. iron dextran - increased uptake at injection site
  5. estrogen - increased uptake in breast tissue
  6. vincristine and doxorubicin - increased renal retention due to nephrotoxicity
130
Q

MDP
a) Explain mechanism of renal excretion

b) Critical organ (other than bone) how to reduce dose to that organ

A

a) Glomerular filtration

b) Bladder - frequent voiding

131
Q

CRMO
a) Name 3 clinical features (3 marks)

b) Name 2 bone scan findings (2 marks)

A

a)
1. Presents in late childhood/early adolescence with a single, locally painful, tender and swollen site- most commonly in the tibia.
2. Bone biopsy culture is negative.
3. Female predominance (2:1)

b)
1. Multifocal symmetric areas of increased tracer accumulation (in 2/3 of cases)
2. Characteristic involvement of the medial third of the clavicle (30% of all CRMO lesions are located in the clavicle)

132
Q

Breast cancer.
a) Proportion of positive bone scans in stage I breast cancer?

b) Probability of metastasis in solitary sternal lesion in patient with bone scan?

A

a) 4%

b) 75%

133
Q

A patient with prostate cancer has increased bloodpool and decreased osseous activity on a bone scan. Give 4 reasons for this biodistribution.

A 
Imaging too early
Interstitial injection
Corticosteroids
Elevated serum aluminum levels
Congestive heart failure
Poor hydration
Poor radiopharmaceutical preparation – dissociation of tag
134
Q

Give 3 inflammatory spondyloarthropathies.

A

Ankylosing spondylitis
Psoriatic
Enteropathic
Reactive (Reiter)

135
Q

What is a superscan? List 4 reasons other than malignancy for a superscan?

A

Diffuse uptake through the skeleton leading to beautiful bone scan with decreased soft tissue or absent kidney.

Nonmalignant Causes:
●	Renal osteodystrophy
●	Primary hyperparathyroidism
●	Osteomalacia
●	Paget disease
●	myelofibrosis
●	mastocytosis
136
Q

Define calciphylaxis.

A

Disorder that results in skin ischemia and necrosis from decreased arterial blood flow in the dermo-hypodermic arterioles. Most commonly seen in end stage renal disease.

137
Q

Causes of MDP uptake in the myocardium

A 
Infarct
Amyloidosis
Metastatic calcification (any cause)
Hyperparathyroidism
Long standing CHF
Cardiomyopathy
Myocardial contusion
Post-cardioversion
Myocarditis
Unstable angina
138
Q

Stress fracture - what is time difference between radiographic and scintigraphic appearance?

A

Radiographs – 7-10 days

Bone scintigraphy – 1-3 days depending on patient age

139
Q

MDP

a) When is peak bone uptake or activity?
b) When is best bone-target to background ratio?

A

5 hours (why is NM Requisites so different at 1hr?)

6-12 hours

140
Q

MDP bone scan: time when uptake is maximal & best time for uptake vs. background. What are 2 most important determinants of increased uptake on MDP bone scan

A

About 50% of the compound will be affixed to bone by 2-4 hours after injection. Maximal skeletal uptake occurs at 5 hours - other source: 1-2 hour

Factors determining increased uptake:

  • rate of blood flow
  • rate of bone formation – osteoblastic activity
  • extraction efficiency
  • interruption of sympathetic supply
141
Q

What are 3 most common factors that predispose to heterotopic ossification?

A

Common etiologies include:
Musculoskeletal trauma (most common)
Burns
Brain or Spinal Cord injury

142
Q

a) What is flare response?

b) Why do you see flare response?

A

Flare phenomenon = paradoxical increase in abnormal tracer uptake on bone scan (#/intensity) after therapy. It may be seen between 2 weeks and 3 months post therapy and it should subsequently decrease on repeat exam at 2-3 months but may last up to 6 months.

It is due to increased osteoblastic activity caused by skeletal healing in response to therapy, a favorable response.

143
Q

Bone scan of suspected NAT. List 3 steps to take or recommend to pediatrician. (Alternate recall: A child is admitted to ICU with fever, bone scan shows pattern suspicious for non-accidental injury. What are 3 things to tell the pediatrician?)

A
  • Communicate your suspicion for child abuse to the pediatrician
  • Perform a radiographic skeletal survey
  • Perform NaF PET if available (ref Treves)
  • +/- additional imaging such as CT Head
144
Q

A 8 month child is admitted to ICU with fever and seizure. a )What is the most specific fracture on bone scan for non-accidental trauma?

A

Most specific fracture is the CML (Classic metaphyseal lesion), although bone scan has low sensitivity for its detection. Rib fractures are the most common fracture in child abuse, and bone scan is more sensitive than x-ray at detecting rib fractures (pattern: multiple posterior rib fractures).

145
Q

List 4 malignancies that frequently result in a negative bone scan

A

Multiple Myeloma, RCC, Thyroid, LCH

146
Q

Match the terms “intense,” “moderate,” “mild,” “isointense,” “variable,” and “cold” for uptake on bone scan for:

a) osteoid osteoma
b) adimantinoma
c) fibrous cortical defect
d) fibrous dysplasia
e) cortical desmoid
f) bone island

A

a) osteoid osteoma - intense
b) adimantinoma - intense
c) fibrous cortical defect - mild-isointense
d) fibrous dysplasia - intense
e) cortical desmoid - intense
f) bone island - mild-isointense

147
Q

3 stages (or phases) of complex regional pain syndrome 1?

A

CRPS has two forms:
CRPS 1 is a chronic nerve disorder that occurs most often in the arms or legs after a minor injury (Sudeck atrophy, RSD).
CRPS 2 is caused by an injury to the nerve (causalgia).

It is now instead thought that patients are likely to have one of the three following types of disease progression:
1. “Stage” one is characterized by severe, burning pain at the site of the injury, muscle spasms, joint stiffness, restricted mobility, rapid hair and nail growth, and vasospasm (causes changes in skin color and temperature), +/- hyperhidrosis (increased sweating). In mild cases this stage lasts a few weeks.

  1. “Stage” two is characterized by more intense pain. Swelling spreads, hair growth diminishes, nails become cracked, brittle, grooved, and spotty, osteoporosis becomes severe
  2. “Stage” three is characterized by unyielding pain, and irreversible muscle atrophy, flexor tendon contractions, and marked bone softening and thinning.
148
Q

Why is a bone scan preferred for evaluation of metastases in neuroblastoma over MIBG, particularly if the patient is <18 months old)? Name 3 causes of false positives and 1 cause of false negative on a bone scan for neuroblastoma.

A

Why preferred?
o Said sensitivity for bone metastases is lower with mIBG than bone scan
o (may differentiate cortical from medullary)
initial assessment should include both MDP bone scan and MIBG scintigraphy. MIBG assesses response to treatment of primary tumour and metastatic sites.

False positive
o Aneurysmal bone cyst
o Fibrous dysplasia
o Osteoid osteoma
 - nfection, fracture

False negative
o Too small a lesion
- marrow involvement only

149
Q

List the anatomical site affected in the following: Kohler, Osgood-Schlatter, Legg-Calve-Perthes, Kienbock, Thiemann.

A

a. Kohler Navicular bone AVN
b. Osgood-Schlatter Patellar tendon insertion on tibia tuberosity, chronic microtrauma
c. Legg-Calve-Perthes Femoral head AVN
d. Kienbock Lunate AVN
e. Thiemann Phalangeal epiphyses AVN (PIP joints)

150
Q 
Fill in the following table for lesions on bone SPECT/CT, assuming there has been no trauma:
Enchondroma 
Osteoid osteoma
osteochondroma
GCT
A

Enchondroma - mild; intramedullary; diaphyseal; lytic

Osteoid osteoma - high; cortical; ? ; sclerotic with nidus

Osteochondroma - variable/usually high; cortical; metaphyseal; sclerotic with corticomedullary continuity

GCT - high; intramedullary; epiphyseal; lytic

151
Q

How does NaF bone uptake work?

A

F- substitutes for -OH group (hydroxyl ion) in the hydroxyapatite crystal

152
Q

List location of uptake

a) 18F-FDDNP 
b) flumazenil 
c) 18F-DOPA 
d) 123I FP-CIT 
e) 11C-DTBZ  
f) 11C-nicotine
A

a) 18F-FDDNP – B amyloid plaques & neurofibrillary tangles (Alzheimer’s)
b) flumazenil – central GABA receptors (extra)
c) 18F-DOPA – L-amino acid transporter (Parkison’s)
d) 123I FP-CIT – Dopamine transporter (presynaptic; Parkinson’s)
e) 11C-DTBZ - Vesicular monoamine transporter (presynaptic; Parkinson’s)
f) 11C-nicotine – nicotinic receptors (extra)

153
Q

2 characteristics in the pathologic examination of the brain on autopsy in Alzheimer’s disease patients. What region(s) are first affected on FDG-PET of Alzheimer’s disease? What specific pathologic finding shows potential for in vivo imaging?

A

2 characteristics
o Beta amyloid plaque
o Neurofibrillary tangles consisting of tau protein

What regions
o Posterior temporo-parietal and posterior cingulate gyrus

Pathologic finding with potential for in vivo imaging
o Beta amyloid plaque imaging is currently being investigated (e.g., with agents like 18Fflorbetapir), but combined beta amyloid plaque and neurofibrillary tangle agents may be better (e.g., 18F-FDDNP)

154
Q

Name a WHO low grade pediatric intracranial tumor that demonstrates increased FDG activity.

A

pilocytic astrocytoma
ganglioglioma
choroid plexus papilloma

155
Q

What are the 3 main classes of dementia imaged with FDG PET (or, which classes of dementia are better imaged with PET than SPECT?).

A

Alzheimer’s, Lewy body dementia, frontotemporal dementia (Pick disease)

156
Q

Pattern of brain uptake for 1 month old child? When does it resemble adult?

A

Neonate: increased uptake in thalamus, brainstem, midbrain, cerebellum and sensorimotor cortex.
3-6 months of age: above, plus, increase uptake in basal ganglia, parietal temporal and occipital lobes.
6-12 months: frontal lobe has increasing uptake
By 1 year, pattern of GLUCOSE uptake is qualitatively similar to adult.
(auntminnie says that for PERFUSION, pattern is similar to adult by 2 years.

157
Q

Name 3 principal symptoms of dementia with Lewy Bodies.

Features on imaging?

A

Dementia, visual hallucinations, and parkinsonism

Similar in distribution to AD (posterior temporoparietal decreased uptake), but greater posterior temporal decrease, involvement of the occipital cortex, and can demonstrate sparing of the posterior cingulate gyrus

158
Q

What is crossed cerebellar diaschisis.

A

Hypometabolism (seen on PET) and hypoperfusion (seen on SPECT) in the cerebellum contralateral to a focal supratentorial lesion (eg infarct or tumor), due to interruption of the cerebropontocerebellar pathways (deafferentation)

159
Q

Clinical features of parkinsonism.

A

● tremor of the hands, arms, legs, jaw and face
● rigidity or stiffness of the limbs and trunk
● bradykinesia or slowness of movement
● postural instability or impaired balance and coordination

160
Q

How does I-βCIT look on scan? If patient has left sided symptoms, which side on scan is there a change?

A

Cocaine analog (looks like F-dopa, localizes in presynaptic dopamine transporters). Has decreased striatal uptake in Parkinsons. Substantial striatal specificity.

If unilateral symptoms, decreased contralateral tracer uptake. Predominantly decreased in the putamen.

161
Q

Brain death

a) main clinical finding (1 mark)
b) List 4 confirmatory tests (4 marks)
c) What do you have to exclude for diagnosis

A

a) Coma/unresponsiveness
Absence of brainstem reflexes
Apnea

b) Pupillary reflex, gag reflex, oculovestibular reflex and apnea tests

c)
Shock/ hypotension
Hypothermia -temperature < 32°C
Drugs known to alter neurologic, neuromuscular function and electroencephalographic testing, like anaesthetic agents, neuroparalytic drugs, methaqualone, barbiturates, benzodiazepines, high dose bretylium, amitryptiline, meprobamate, trichloroethylene, alcohols.
Brain stem encephalitis.
Guillain- Barre' syndrome.
Encephlopathy associated with hepatic failure, uraemia and hyperosmolar coma
Severe hypophosphatemia.
162
Q

VP shunt study

a) Dose and radiopharmaceutical (1 mark)
b) Normal time for abdominal activity

A

Tc-DTPA 0.5-1 mCi
In-111-DTPA can be used

Normal time for abdominal activity ~15-20 min

163
Q

a) What is the purpose of VP shunts?
b) What portion of the shunt more commonly occludes?
c) What tracer is used?
d) What is the dose?

A

a) To treat the symptoms of hydrocephalus
b) Distal limb
c) 99mTc-DTPA, 111In-DTPA, and 99mTc-pertechnetate
d) 99mTc-DTPA 0.5 mCi

164
Q

For cisternogram in VP shunt eval, how much and what do you give? Most common site of obstruction? By when do you expect to see peritoneal activity?

A

250 uCi 111In-DTPA or 0.5-1 mCi Tc-DTPA, make sure it is pyrogen free.
Ventricular catheter obstruction is the most common, and can result from:
• Fibrin debris
• Blood clot
• Ingrowth of choroids plexus or glial elements

Clearance from the reservoir should occur by 10 minutes. Activity should be visualized in the peritoneal cavity by 15-20 minutes.

165
Q

Name 8 organs with a probability between (23-87%) to harbor metastatic melanoma.

A 
brain
thryoid
heart
lung
liver
adrenal
pancreas
spleen
166
Q

Name 6 tumors with low FDG avidity.

A 
bronchoalveolar CA/ Lung adenocarcinoma in situ
·        carcinoid
·        prostate CA
·        low grade glioma
·        low grade HCC
·        renal cell CA
·        mucinous tumours
Cholangiocarcinoma
Bladder Cancer
Lobular Breast Carcinoma
167
Q

Why mucinous shows decreased FDG uptake?

A

Mucin is metabolically inert and avascular. Sensitivity: 59%

Types: Ovarian cystadenoma/carcinoma, mucinous cystic pancreatic tumor, mucinous of the appendix which can lead to a mucocele of the appendix, mucinous carcinoma of the breast (rare), mucinous carcinoma of the colon is the most common. BOCAP

EXTRA - Mucinous tumors produce a glycoprotein that is similar to immature bone scaffolding and can demonstrate increased MDP uptake.

168
Q

What is the new term for BAC? (0.5 marks) and what is maximum size?

A

There are multiple new terms, not just one. Because they are asking for size, I think I would answer:
Adenocarcinoma in situ (AIS) and Minimally invasive adenocarcinoma (MIA), <= 3cm.

169
Q

When to image/ how long to wait before PET (FDG)

a) post-chemo 3 weeks
b) post-GCSF

\

A

PET at least 3 weeks (preferably 6-8) following chemotherapy and preferably 8 to 12 weeks after radiation therapy

10 days vs 2-4 weeks after G-CSF administration is recommended to minimize the influence of G-CSF on the bone marrow.

170
Q

Patient Prep for FDG in 1) malignant cancer 2) cardiac sarcoid 3) viability

A

Cancer: fast x4h, avoid muscular activity, etc.

Sarcoid: low carb, high protein diet x1d before scan, fast 12h beforehand.

Viability: low fat, high carb diet morning of exam (or IV glucose 1-3h before injection).

171
Q

What is Deauville criteria?

A

Deauville 5-point scoring system is an internationally accepted and utilized five-point scoring system for the Fluorodeoxyglucose (FDG) avidity of a Hodgkin’s lymphoma or Non-Hodgkin’s lymphoma tumor mass as seen on FDG Positron emission tomography

172
Q

List Deauville criteria (2.5 marks)

A

Deauville 1 – No FDG activity
Deauville 2 – FDG activity <= mediastinal blood pool
Deauville 3 – FDG activity > mediastinal blood pool and <= Liver
Deauville 4 – FDG activity greater than liver
Deauville 5 - FDG activity markedly greater than liver (2-3x) and/or new lesions

Deauville X - activity unrelated to cancer

173
Q

List interpretation of Deauville criteria (2.5 marks)

A

Complete metabolic response = Deauville 1-3 after therapy with or without residual mass

Partial metabolic response = Deauville 4-5 after therapy with a decrease in FDG activity compared with baseline and residual masses of any size

No metabolic response = 4 or 5 with no obvious change in FDG activity (at interim or end of treatment)

Progressive disease = 4 or 5 with increase compared with baseline or new FDG avid foci consistent with lymphoma (at interim or end of treatment)

174
Q

. Regarding the Ann Arbor classification (with Colbert modification)?

  1. What is stage II?
  2. What is meant by “X”?
  3. What are B symptoms?
A

Stage II – 2 sites of disease on the same side of the diaphragm.

X indicates largest disease deposit is greater than 10 cm or mediastinum wider than 3rd of chest on CXR
B symptoms include :
- recurrent significant night time sweating which requires the changing of sheets
- weight loss (greater than 10%) without dietary change in < 6 months
- Fever of > than 38o without other focus.

175
Q

A patient is being evaluated for Eaton Lambert syndrome. CT scans have been negative. Why is FDG PET used?

A

A study demonstrated extrathoracic SCLC in 3 patients with this syndrome that had normal Chest CT

Eaton Lambert myasthenia syndrome commonly presents as a paraneoplastic syndrome secondary to malignancy (most often lung ca)

176
Q

What are the criteria for the International prognostic score? (Not be confused with International Prognostic Index)

A

The IPS incorporates seven clinical parameters that were demonstrated to be independently associated with a poorer outcome (for HL):

  • male sex
  • age >= 45 years
  • stage IV disease
  • hemoglobin < 105 g/L
  • leukocytosis: WBC count > 15 x 10^9 / L
  • lymphopenia: lymphocyte count < 0.6 x 10^9/ L or < 8% of differential
  • albumin < 40 g/L
177
Q

The International Prognostic Index (IPI) is used for prognosis of patients with aggressive NHL

A
  • Age > 60yrs
  • Stage 3 or 4 disease
  • Elevated serum LDH
  • ECOG performance status 2,3,4
  • More than one extranodal site
178
Q

What is the TNM stage of the following lung cancers

A
  1. 1.8 cm tumor, SUV 12, ipsilateral paratracheal lymph node 0.8 cm with SUV of 1.0, no metastases. T1aN0M0 49% 5 year survival
  2. 2.8 cm tumor in right lung, SUV 12, pericardial effusion with uptake, subcarinal and left lower paratracheal lymph node activity. T1bN3M1a
  3. Tumor with pleural nodularity and activity. TXNXM1a
179
Q

According to the latest AJCC, what would be TNM classification and stage for the following: (A) 2.5 cm isolated lung lesion with solitary ipsilateral hilar lymph node involvement and no distant metastases.

(B) 4.0 cm lung lesion with chest wall invasion, bilateral lower paratracheal lymph nodes, and no distant metastases.

A

a. Stage IIA
b. Stage IIIB
(Remember: Stage IIIA is operable, IIIB is not)

  • SEE RECALL 2013-2016 PAGE 130
180
Q

Why hepatoma shows decreased FDG uptake?

A

Because of higher expression of:
glucose 6 phosphatase (dephosphorylate the FDG and allow it to be transported back out of the cell)
p-glycoprotein, which acts to kick FDG out of cells (there is greater expression of p-glycoprotein in well differentiated tumors).

Also, HCC has variable expression of glucose transporters and hexokinase.

181
Q

Hepatocellular carcinoma may have decreased uptake on FDG-PET. What is the effect of tumour expression of P-glycoprotein on FDG uptake? What is the effect of serum alpha fetoprotein levels on FDG uptake? What is the effect of FDG uptake on prognosis?

A

P-glycoprotein effect = “multidrug resistance gene”: ↓uptake due to export of 6’-FDG-P
Alpha fetoprotein: ↑uptake
Effect of FDG uptake on prognosis: ↑ uptake indicates worse prognosis (less differentiated, higher metabolic activity)

182
Q

Multiple myeloma - name 3 radionuclides for imaging

A

F18 FDG, Tc99m Sestamibi, In111 Pentetreotide

183
Q

111In-pentreotide
a) percent hormonal uptake (1 mark)

b) biological T1/2
c) primary elimination
d) adult Dose and how to determine pediatrics dose

A

a) Hormonal effect of pentetreotide is approximately 10% that of octreotide
b) 6 hrs
c) Renal

d) 6 mCi in adults
(0. 08 mCi/kg) in children

184
Q

111In-pentreotide. List 4 non-cancer-related uptake

A

· Lung uptake from radiation therapy
· Lung uptake from Bleomycin
· Joints in RA
· Hila in the setting of upper respiratory tract infection
· Increased thyroid uptake Graves
· Surgical wounds, stomies, drains

185
Q

What is the sensitivity and specificity for 123I and 131I-MIBG for detection of pheochromocytoma and paraganglioma? Name 2 alternative radiotracers that can be used for evaluation of pheochromocytoma and paraganglioma.

A

• Sensitivity and specificity (what I put—NOT SURE):
o Pheochromocytoma: 131I MIBG or 123I MIBG 90%, (Octreotide 85%, Both 95% sensitivity)

o Paraganglioma: 42% (75% 123I-MIBG, 50% 131I-MIBG); Sp ?%

• Alternatives
o 111In-Pentetreotide
o 18F-DOPA

186
Q

a) What is Curie Score (1 mark)
b) List 3 things to look at for Curie Score (3 marks)
c) Patient has 2 femoral lesions and 1 contralateral femoral lesion completely involving femur. What is Curie stage? (1 mark)

A

a) Objective semi-quantitative score to describe Neuroblastoma disease burden with I-MIBG measured at 10 sites (9 MSK 1 Abd).
b) site of lesion, number of lesions per site, proportion of total site involvement.
c) 3 (both femurs counts as one compartment, max score for each compartment is 3)

187
Q

What tumor is associated with opsoclonus in a child. (uncontrolled eye movement)

A

Neuroblastoma

188
Q

Name tumors that are MIBG avid.

A 
Neuroblastoma
Pheochromocytoma
Paraganglioma
Carcinoid
Medullary thyroid cancer
189
Q

What is a name for extra-adrenal pheo? 2 pet tracers other than fdg and mibg to diagnosis it.

A

paraganglioma

F-18 DOPA and Ga-68 DOTATATE

190
Q

MIBG drugs – 3 classes that affect uptake and an example in each.

A

Antihypertensives: Beta blockers (Labetalol), CCB’s (diltiazem, verapamil, nifedipine)

Antidepressants: TCAs (amitriptyline)

Antipsychotics: phenothiazines (fluphenazine)

191
Q

What are 4 parameters to assess before treating someone with DCIS according to NCCN?

A

Hx/Px
Mammogram(+/- MRI),
ER/PR receptor testing from biopsy,
genetic testing for BRCA etc..

192
Q

Aside from FDG, what PET agent is used for gynecological cancers?

A

16α-18F-fluoro-17β-estradiol (18F-FES)

193
Q

.3 pet tracers for well differentiated prostate cancer and their mechanisms.

A

11C-acetate -> fatty acid synthesis

11C-methionine - AA transport and protein synthesis

11C-choline - choline turnover

18F-FDHT - androgen receptor expression

Increased androgen receptor expression -([18F]fluorodihydrotestosterone (FDHT))

194
Q

.3 ways to determine pediatrics dosing.

A

Weight based formula (Clark’s): Adult dose x (child weight (lbs)/150) (or 70kg instead of lbs)

For kids under 2 (Fried’s): Adult dose x (age in months/150)

BSA formula: Adult dose x (BSA/1.73)

EANM Dose card

195
Q

Sizes

a) Technegas 
b) Radioaerosol 
c) MAA 
d) red blood cell
A

a) Technegas - 0.005-0.150 μm
b) Radioaerosol - 0.1 – 0.5 μm
c) MAA - 10-90 μm
d) red blood cell - 6-8 μm

196
Q

What is the size of Technegas particles? What is the usual size of MAA particles? If the Technegas ventilation study is to be performed before the MAA study, what ratio of activity should be used for the ventilation vs. perfusion?

A

a. Technegas:0.005-0.150 μm
b. MAA: most should be 10-90um, none <10um or >150um
c. 3-4x higher

197
Q

4 indications of VQ scan in a child.

A 
Pulmonary embolism
Structural abnormalities of the chest (eg, Congenital diaphragmatic hernia, scoliosis)
Congenital heart defects
Swyer James syndrome
Pulmonary sequestration
198
Q

3 causes of non-segmental defects on lung scan.

A

Pleural fluid
Atelectasis
Malignancy
Pneumonia

199
Q

5 causes of unilateral decreased perfusion to a lung.

A
  1. PE
  2. Bronchogenic carcinoma
  3. Mucous plug
  4. Congenital abscense of pulmonary artery
  5. Swyer James syndrome
200
Q

Ventilation agents. Given table of “133Xe,” “127Xe,” “81Kr,” and “99mTechnegas” and asked to fill in T1/2 and keV of each (2 marks total)

A

133Xe - 5.2d; 81 keV
127Xe - 36d; 172, 203, 375 keV
81mKr - 13.1s; 191 keV
99mTechnegas - 6h; 140keV

201
Q

What happens to MAA (excretion)?

What is the ultimate fate of MAA trapped in lungs?

A

Occludes precapillary arterioles, eventually enter systemic circulation and are phagocytosed by RES with an effective half life 1.5-3.8 hours

202
Q

Compare CT and V/Q in the following conditions.

a. Breast dose
b. More likely to have a technical problem
c. For anomalies in the lung bases.
d. Chronic pulmonary emboli

A

a. Breast dose CT> V/Q
b. More likely to have a technical problem CT > V/Q
c. For anomalies in the lung bases. Think they are getting at the preliminary abnormal radiograph improving CTPA performance ???
d. Chronic pulmonary emboli V/Q better than CT

203
Q

What are 2 (or was it 3?) indications when VQ SPECT is preferred over CTPA? What are 2 situations when CTPA is preferred over VQ SPECT?

A

a. VQ over CTPA:
i. Young women (lower breast dose)
ii. Contrast allergy
iii. Renal dysfunction
iv. Low pre-test prob and normal CXR

b. CTPA over VQ:
i. Abnormal CXR
ii. When an alternative diagnosis other than pulmonary embolism is suspected
iii. Intermediate pretest probability

204
Q

Advantages of SPECT over planar V/Q scanning.

A
  1. More reproducible
  2. Faster to acquire.
  3. Better anatomic (medial basal segments) and contrast resolution
  4. More sensitive, specific and accurate.
  5. Lower number of inconclusive reports
  6. Lower interobserver variability.
  7. Better able to estimate the size of defects
205
Q

Name 5 criteria for very low probability according to PIOPED II.

A
  1. Non-segmental
  2. 1-3 small segmental defects
  3. Q defect < CXR lesion
  4. Stripe sign
  5. Solitary large pleural effusion
  6. Solitary matched V/Q/CXR defect less than 1 segment in mid or upper lung
206
Q

PIOPED II - High probability

A

> = 2 large mismatched V/Q segmental defects

207
Q

4 reference standards used in Pioped 2.

A

They did DSA, CTPA (combined with Well’s score), CTV (of the IVC, pelvic veins, and thighs), compression ultrasound, and VQ.

208
Q

Patient has severe pulmonary hypertension and asks if he will die from VQ study? What do you tell her? What would you tell the technician.

A

No (non-zero risk from any medical procedure, but only tiny fraction of pulmonary capillaries become occluded).

Reduce number of particles to 60,000-100,000.

209
Q

Name 8 risk factors for venous thromboembolism.

A 
• Protein C deficiency
• Protein S deficiency
• Antithrombin III deficiency
• Factor V Leiden
• Malignancy
• Immobility
• Pregnancy
• Polycythemia
- Recent travel
- Recent surgery
210
Q

A patient treated with MIBG develops leukopenia and thrombocytopenia. What are 2 measures that can be taken?

A

Stem cell rescue, platelet transfusion

211
Q

a) List the 3 most commonly used radiopharmaceuticals used for palliation of bone metastases.
b) Which has the longest half life?
c) Which has the highest energy of emission?
d) Which has the highest proportion of gamma photon emissions and could be imaged?

A

a) List the 3 most commonly used radiopharmaceuticals used for palliation of bone metastases. - Sr89-chlorid; Ra223; Sm153
b) Which has the longest half life? Sr89-chloride
c) Which has the highest energy of emission? Ra223
d) Which has the highest proportion of gamma photon emissions and could be imaged? Sm153

Sr89-chloride - 50.5 days; beta: 1460keV; no significant gammas

Sm153-EDTMP - 46 hours; beta 810keV; 28% gammas

Ra223-chloride - 11.4 days; 5780keV alphas, no significant gammas

P32 has the highest energy, but isn’t used anymore.

212
Q

a) Ideal tracer property for radiosynovectomy?
b) Contraindications for radiosynovectomy?
c) How long to wait after arthroscopy?
d) 3 radiotracers for radiosynovectomy?

A

Ideal tracer particle:

  • Beta particle penetrates thickened synovium but does not extend beyond joint.
  • Size: minimize leakage from joint, but small enough to be phagocytosed.
  • Any biologically induced degradation should release radionuclide in a form that’s rapidly cleared from the body.

Contraindications:
○ Absolute :
■ Pregnancy
■ Breastfeeding
■ Local skin infection
■ Ruptured popliteal cyst [knee]
○ Relative
■ children and young patients (<20 years)
■ extensive joint instability with bone destruction
■ evidence of significant cartilage loss within the joint

Time interval between arthroscopy or joint surgery and radiosynovectomy should be 2-6 weeks; between joint puncture and radiosynovectomy is 2 weeks; between repeated treatments in the same joint is 6 months.

213
Q

List 3 radiopharmaceuticals used for radiosynovectomy and their half lives.

A

3 Raditracers:
● 90-Y-citrate - 64.1h
● 186-Re-sulphide - 3.7d
● 169-Er-citrate - 9.4d

214
Q

Zevalin - adverse reaction (1 mark)

A

Prolonged and severe reduction in the number of blood counts

215
Q

What is HAMA?

What percentage do you expect to see it in?

2 issues if patient has had HAMA.

A

Human Anti-Mouse Antibodies.

HAMA response can create problems such as allergic-like reaction to the mouse antibody, rapid removal of the mouse antibody, and weak ability to recruit human immune system processes necessary to clear the targeted antigen

What percentage do you expect to see it in?
3.8% for Zevalin

1) interfere with murine antibody-based immunoassays (such as immunoassays for carcinoembryonic antigen (CEA) and cancer antigen 125;
2) alter biodistribution of Bexxar/Zevalin if retreatment required which would preclude readministration;
3) produce an allergic reaction (even anaphylaxis) if more murine Ab-based agent is given.

216
Q

Name 6 early complications of radioiodine therapy.

A 
Xerostomia
Sialoadenitis
Radiation parotiditis
Nausea and vomiting
Radiation gastritis
Radiation cystitis
Thyroid storm
Loss of taste (acute/chronic)

Late side effects may include temporary infertility (in men this can be permanent as dosages progressively exceed 7.4–11.1 GBq [200–300 mCi]); rarely, permanent damage to the salivary glands resulting in loss of saliva or sialolithiasis, excessive dental caries, and reduced taste; dry eyes; epiphora from scarring of the lacrimal ducts, and possibly the very rare development of other malignancies, including those of the stomach, bladder, colon, and salivary glands, and leukemia.

217
Q

4 key elements of thyroid storm management.

A

1) fever → tx hyperthermia with ice packs/cool blankets + acetaminiophen
2) tachycardia and htn(sympathominetic effects) → tx beta blocker (propranolol)
3) block TH release and peripheral conversion → Lugols or other po iodine
4) decrease TH synthesis → antithyroid meds, PTU preferred b/c it is fast acting and also decreased peripheral conversion warning, significant risk of acute liver failure]

218
Q

How long should be one be on low iodine diet for therapy?

A

7-14d, according to SNM guidelines

219
Q

Role of lithium in iodine treatment for graves.

A

Lithium blocks coupling of iodothyronine residues in thyroid, and inhibits release of T3 and T4.

Used to reduce possibility of thyroid storm.

220
Q

TNM of thyroid cancer. No information on mets, node in paratracheal region only, 2.5 cm thyroid cancer in 40 year old female. Next question and how does stage change if distant mets is present.

A

Looking at staging info in docs (2013-2016 page 146)

221
Q

According to AJCC and ATA guidelines, what stage would a 40y F patient with a 4.0 cm thyroid carcinoma, with 3/12 positive lymph nodes, and no evidence of distant disease be?

A

Stage 1(due to age <55y and no mets)

222
Q

A 46 year old female patient presents post-thyroidectomy for a left-sided 1.0 cm (some recalls said 2.0 cm, but we’re pretty sure it’s 1.0 cm) papillary thyroid carcinoma (follicular variant), with no lymphovascular invasion or evidence of locoregional or distant metastases. According to SNMMI and ATA guidelines, would you recommend this patient have radioiodine ablation? List 6 things that should be done in preparing a patient for radioiodine ablation.

A 
• Recommendation on ablation?
	o Yes (because of unfavourable histology)

• 6 things to prepare
o Low iodine diet
o Check for pregnancy/breastfeeding
o Check TSH if using depletion protocol
o Administer rhTSH (Thyrogen) 0.9 mg IM on days 1 and 2 if using Thyrogen protocol
o Whole body scintigraphy before ablation
o Stop interfering medications

223
Q

Whole body thyroid scintigraphy is normally performed using 10 mCi of 131I-iodide. List 3 things that can be done to reduce stunning if whole body scanning is to be performed before radioiodine ablation?

A
  • ↓dose for whole body scintigraphy to <2 mCi
  • Administer ablation dose immediately after whole body scintigraphy
  • Wait 1-2 weeks after whole body scintigraphy before giving ablation dose
  • Use 123I instead
224
Q

Name 3 hyperthyroid conditions that should not be treated with I-131 therapy.

A

a. Subacute thyroiditis
b. Iodine excess with Jod Basedow decompensation (dietary (e.g., seaweed), medications (iodinated contrast media, amiodarone)
c. Exogenous administration of thyroid hormone (factitious thyrotoxicosis, hamburger thyrotoxicosis)
d. Struma ovarii

225
Q

In selective internal radiotherapy (SIRT), what is the incidence of hepatic radiotoxicity?

What are 2 clinical consequences of hepatic radiotoxicity?

Name 2 risk factors for development of hepatic radiotoxicity.

A

Hepatic radiotoxicity
o 4% (see 2015 answer)

Clinical consequences
o ↑ hepatic enzymes
o Ascites

Fatigue, RUQ pain, weight gain, increased abdominal girth

2 risk factors
o Large volume of disease
o High administered dose
o Pre-existing hepatic cirrhosis
 - number of prior treatments

Nucs Board Review (21 decks)

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