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112 Cards in this Set
- Front
- Back
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Presence of excess amounts of aluminum in TC-99m sulfur colloid preparation leads to abnormal accumulation where? What about aluminum in Tc-99m MDP?
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lungs
liver |
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How often is spatial resolution tested and with what?
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weekly, bar phantom
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How often is peaking of the camera tested?
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daily
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How often should spatial linearity be tested?
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weekly
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half life of samarium?
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67 hours
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DDx of superscan and typical appearance of each?
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diffuse mets - abrupt cutoff at proximal femurs/humeri
metabolic bone disease - head-to-toe multifocal paget's - multifocal |
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What is the % chance of Ca in a cold thyroid nodule?
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15-20%
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I-123 half-life? keV?
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13 hours, 159 keV
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Depths of each dose equivalent:
DDE SDE LDE |
1.0 cm
.007cm 0.3 cm |
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What is the purpose of CEDE?
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provides an estimate of lifetime average radiation dose to an individual from inhalation or ingestion
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mechanism of Thallium-201 in myocardial imaging?
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potassium channel analog and thus redistributes through intact cell membranes on delayed imaging to identify hibernating myocardium
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half-life of thallium-201? energy?
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72 hours, 69 and 81
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Mechanism of MIBI in myocardial imaging?
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mitochondrial binding
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DDx of altered biodistribution of FDG?
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hyperinsulinemia
exercise/myositis brown fat |
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Mechanism of Gallium?
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nonspecific Fe analog mediated by transferrin receptors
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What is better for abdominal imaging, ga-67 or in-111?
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In-111
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half-life of Ga-67? energy?
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78 hours
90,190,290,390 |
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Is Kaposi's sarcoma Ga-67 avid?
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No
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How can you distinguish a Meckel diverticulum from a renal pelvis?
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Lateral views
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Which ventilatory agent will accumulate in a fatty liver?
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Xe-133
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half-life of Xe-133? Energy?
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5.3 days, 81
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If no gallbladder filling after 1 hour?
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30 minutes imaging post morphine
3 hours imaging without morphine |
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DDx for decreased renal uptake on DMSA?
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pyelonephritis
chronic renal scarring tumor |
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What is better to assess adrenal tumors, MIBG or octreoscan?
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MIBG because octreoscan will accumulate in renal cortex
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What is used for a parathyroid scan?
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Tc99m-MIBI
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Two forms of dual subtraction that can be used in parathyroid scanning?
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Thallium - pertechnetate
MIBI - I-123 |
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Which thyroid cancers are I-131 avid?
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papillary and follicular
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what form of tracers can be used for medullary thyroid carcinoma?
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neuroendocrine
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In the setting of a patient with prior thyroid ablation, rising thyroglobulin, and a recent negative thyroid scan what should you do?
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A PET scan - the tumor may have dedifferentiated
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What happens with free-pertechnetate artifact on a tagged rbc scan?
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Gastric and thyroid accumulation of radiotracer
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Which form of tagging rbcs has the highest efficiency?
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In vitro
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Mickey Mouse vertebral body?
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Paget's
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Symmetric perfusion decrease to upper lobes with normal ventilation?
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artifact from upright injection of tc99m-MAA
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What happens if you 'draw back' the syringe prior to injection of MAA?
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you will get clumping and 'hot clots' on the scan
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Why do ventilation before perfusion:
- in the case of Xe-133? - in the case of DTPA? |
Xe- avoid downscatter from DTPA (higher energy then Xe)
DTPA - avoid overwhelming radioactivity (lower dose DTPA used in ventilation compared to perfusion) |
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What is the size of a capillary?
What particle size should 90% of MAA particles fall within? How many capillaries are temporarily occluded with a normal dose? |
7 micrometers
10-90 micrometers (none greater than 150) 0.1% |
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Gastric emptying:
Solid meal liquid meal |
solid - linear
liquid - exponential, no lag phase |
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What is normal gastric emptying?
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>90% at four hours
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Why might there be an apparent increase in gastric activity over time in a gastric emptying study?
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Poster->anterior movement of tracer from fundus to antrum
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Renal pelvic t1/2 washout
Normal indeterminate obstructed |
<10 min
10-20 min >20 min |
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What renal parameter is MAG3 a function of?
What renal parameteris DTPA a function of? |
active tubular secretion
GFR |
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Where might MAG3 show up on delayed images?
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GB and small bowel
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Where is the ROI drawn for determining split renal function? For washout?
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renal parenchyma
collecting systems |
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What phases of a bone scan are hot with a stress fx?
shin splints? |
all three
only delayed |
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What is the clinical significance of having too much Mo-99 contamination in Tc-99m?
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It increases the dose to the patient (740 keV photons)
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How is radiochemical purity tested?
What group are radiochemical purity standards set by? |
TLC (thin-layer chromatography)
US Pharmocopaeia (NOT NRC) |
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Why use a plastic syringe shield when injecting samarium?
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The beta particle interaction with the lead increases the dose to the injecting individual
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Samarium-153 (Quadramet)
Strontium-89 (Metastron) |
beta and gamma emitter and thus CAN be imaged
only a beta emitter |
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What is a good dual energy study for an infected prosthesis?
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In-111 wbc - tc99m-SC
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Diaphragm artifact on myocardial scan?
Breast artifact on myocardial scan? |
inferior (RCA territory)
anteroseptal apex (LAD territory) |
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How often is extrinsic flood performed?
What is the difference between intrinsic and extrinsic flood? |
daily
extrinsic is with collimators on - measures entire system intrinsic is with collimators off - measures crystal and electronics |
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Metastatic patterns of:
papillary thyroid Ca follicular |
regional (nodes)
distant (hematogenous) |
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Medullary carcinoma of thyroid associated with what type of cell and what syndrome?
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MENII, parafollicular C cells
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What MUGA criteria are used to clinically stop doxorubicin?
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LEVF decrease by >10% plus LVEF <50%
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Two ways to perform a MUGA scan? In what projections are images acquired for each
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equilibrium and first pass
equilibrium - LAO, anterior and left lateral first pass - RAO |
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what radiotracer is used for a MUGA scan?
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tc99m-rbc
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What is the reason for an abnormal renal curve in a captopril study in the kidney with renal artery stenosis when MAG3 is used? DTPA?
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MAG3-delayed tubular washour
DTPA - decreased GFR |
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What is a 'recordable' event?
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A 'misadmininstration' that does not meet the dose criteria for a medical event aka 'reportable' event to the NRC.
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What is given prior to a hepatobiliary scan looking for biliary atresia?
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Ursodeoxycholic acid or phenobarbital one to two days before to improve hepatic function.
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Purposes of drugs before a Meckel scan:
pentagastrin cimetidine glucagon |
-increases gastric mucosal uptake
-decreases mucosal secretion -decreases bowel motion |
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What is a 'rim sign' on a HIDA scan mean?
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gangrenous cholecystitis
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Does the presence of a gallbladder rule out biliary atresia?
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No, 25% will have a gallbladder
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What does it mean when Xe-133 accumulates around the pleural space?
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bronchopleural fistula
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Types of thyroiditis
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granulomatous (DeQuervain)
silent (lymphocytic) postpartum |
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Three ways to decrease brown fat uptake
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propranolol
low-carbohydrate diet vigorous warming before scan |
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Tc99m-HMPAO-wbc versus In-111-oxime-wbc
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HMPAO:
allows for higher dose and thus better images earlier imaging In-111 More specific label |
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What may simulate abnormal bowel uptake on a wbc scan?
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swallowing of wbcs from sinusitis
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What is the advantage of direct radionuclide cystography?
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lower dose, more sensitive
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What tracer is used in radionuclide cystography?
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tc99m-pertechnetate
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What is a useful implication of NaF-18
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PET bone scan
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what is the chance a solitary rib lesion is a metastasis?
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10%
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What is 'contour mapping' sign on a V/Q scan?
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diffuse tumor microemboli
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What does acetazolamide do?
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carbonic anhydrase inhibitor which causes cerebral and renal vasodilation.
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Name twocerebral cortical perfusion agents
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HMPAO, ECD
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In-111-wbc/tc99m-MDP for diabetic foot?
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cellulitis hot on wbc scan only
diabetic foot hot on bone scan only osteomyelitis is hot on both |
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Cavernous hemagioma shows up on?
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tc99m-rbc
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does FNH show up on tc99m-rbc?
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no
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4 minimally-fdg-avid lymphomas?
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MALT
small lymphocytic cutaneous anaplastic large t-cell splenic marginal zone |
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Increased uptake in quadrate lobe on tc99m-sc?
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svc syndrome
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Increased uptake in caudate lobe on tc99m-sc
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budd-chiari
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Three hepatic lesions that can be hot on Tc99m-sc?
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fnh
hemangioma regenerating nodule |
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Osteoid osteoma appearance on bone scan?
How about NOF and bone island? |
hot on all three phases
both negative |
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What is appearance of hepatic cavernous hemangioma on tc99m-rbc
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hot
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Administration of TcO4 and I-123 for thyroid scan?
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TcO4 is IV
I-123 is oral |
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ATN from rejection?
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ATN will show no excretion with rising renogram over time
rejection will show abnormal flow/extraction |
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What can mimic ATN on a MAG3 scan?
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poor hydration
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There is increased uptake on a PET/CT adjacent overlying the location of a chest port. You suspect this is artifact based on the large difference of keV between the CT scan and the 511 keV energy. How do you confirm this?
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See if it goes away on non-corrected images
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What drugs interfere with thyroid trapping?
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perchlorate and nitroprusside
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What drugs interfere with thyroid organification?
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methimazole, PTU, sulfonamides
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What does the recovery phase of thyroiditis look like on tc04 and i-123? what does thyroiditis look like before the recovery phase?
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trapping but no organification
low trapping and organification |
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Most common combos for rest/stress myocardial scans? (2)
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Th-201 (rest), tc-tetrofosmin (stress)
low-dose tc-tetrofosmin (rest), high-dose tc-tetrofosmin (stress) |
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What is a better way to perform cardiac perfusion imaging regarding spatial resolution?
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N13 or Rb82 PET
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Other than Th-201 how can cardiac viability be performed? Adavantages?
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FDG-PET - better images, lower dose
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Why might liver and spleen show up on a lymphoscintigraphy exam?
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If SC gets in a vein
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What does RDS show on a bone scan? What it it's chronic RDS?
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Increased uptake on all phases
it can show decreased activity on all three phases (chronic disuse) |
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What is the pledget count to blood ratio needed to make a positive dx for CSF leak?
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3:1
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Two radiolabeled Ab therapies for relapsed follicular or low-grade NHL?
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Bexxar - 1-131 beta/gamma emitter, can be used low-does for imaging/high dose for therapy, complicated dosing because of gamma component, requires thyroid blocking, cheaper
Zevalin - yytrium-90 beta emitter. In-111 gamma must be used for imaging, better images, easier dosing. $$$ |
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t1/2 of yttrium-90
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64 hours
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t/12 of strontium-89?
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50.5 days
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Of Zevalin and Bexxar (yttrium-90 and I-131 beta/gamma) which should you inject with a plastic syringe shield?
What is unique about the myelosuppression with these drugs? Can these patients be treated as outpatients? |
Zevalin (path of beta particle is much further than the Bexxar beta component)
suppression occurs much later (8-12 weeks as opposed to 4) yes |
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What is given prior to both Zevalin and Bexxar therapy?
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rituximab - provides therapeutic effect from naked Abs and destructive crossfire of beta emissions
if response to rituximab is minimal, respons to Bexxar or Zevalin may be minimal |
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What is the purpose of Prostacint-In-111?
When is Prostacint injected? What study is done in conjunction? |
Evaluate for soft tissue prostate mets
four days prior tagged-rbc to reduce false positive and map blood pool |
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Physiologic activity of wbc labeled to HMPAO?
Physiologic activity of wbc labeled to In-111? |
liver, spleen, BM, bladder
same without bladder |
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volume of blood a tagged rbc scan can detect?
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0.1-0.2 mL/hour
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What happens if patient has had caffeine prior to adenosine stress study?
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May cause false negative
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Balanced three-vessel disease may appear normal on a myocardial scan because it represents relative perfusion. Therefore, what additional parameter should be evaluated?
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TID
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What must postop FEV1 be to consider pneumonectomy?
At what preop volume should this calculation be performed? How do you calculate? |
> 800 mL
preop FEV1 <2000mL (100%-geometric mean % of desired lung)*preop FEV1 |
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Sickle cell bone infarcts versus polyostotic bone process?
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look for increased uptake in the spleen for sickle cell
Also, mets usually more proximal, infarcts can be anywhere |
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What is the t1/2 of Rb-82
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75 seconds
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What type of PET scanner increases the SNR without compromising spatial resolution?
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time-of-flight
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What are two relative contraindications to MAA injection?
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severe pulmonary HTN and R->L shunt
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List five positron nuclides?
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F-18
Rb-82 N-13 C-11 O-15 |
