radcards nuclear medicine

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what is the routine for cardiac thallium imaging: inject 2-3 mCi
image at 10 min with two windows, 69-87 keV and 167 keV
what predictive info does thallium give in MI: size of thallium infarct predicts income:
>40% of LV = 92% chance of mortality over next 9 months
<40% of LV = 7% mortality
what is adequate exercise in thallium cardiac stress imaging: 85% of maxiumum HR (220-age) or 250 000 double product
when do you stop a stress test: symptoms
arrhythmia
2nd or 3rd degree heart block
ST depression over 3 mm
systolic BP decrease or HTN > 240/120
how do you tell if there was adequate exercise at imaging: no liver uptake
how often do areas of ischemia fill in delayed on standard thallium: 15-35%

*pearl* reinjection reduces this to negligible
how is a dipyridamole stress test performed: give 140 ug/kg/min DP for 4 min
wait 7-9 min and inject thallium
wait 5 min and image

*pearl* reverse DP with 50-100mg of aminnophylline
how do you perform an adenosine stress test: give 140 ug/kg/min adenosine for 6 min
give thallium at 3 min
image 5 minutes later

*pearl* adenosine's half-life is seconds, so turn it off to reverse it
which type of lymphoma is best seen by gallium: hodgkin's > non-hodgkin's
which type of hodgkin's is toughest to see on gallium: lymphocyte predominant

*pearl* it also has the best prognosis
what tumors take up gallium: melanoma
lung ca
head and neck ca
sarcoma
gynecologic tumors
why must gallium be imaged late: so that kidney, lung and bowel activity is cleared - usually by 24 hours
ddx: lung uptake with gallium: Some Causes of Lung Uptake Are Tough to Remember Properly

sarcoid
CMV
lymphoma
UIP (IPF)
asbestosis/silicosis
TB/fungus
radiation/chemotherapy
PCP
when should you use gallium or indium in infection imaging: indium for most bone and belly imaging
gallium for spine imaging
how do you tell infection with bone scan and gallium imaging together: it's all relative
gallium > MDP uptake - infection
MDP > gallium - no infection
how do you image prostheses: sulfur colloid and gallium - sub out the marrow on SC from the gallium
on V/Q imaging, what is the drawback of Xe-133 imaging: low energy (keV = 81)
down scatter from Tc perfusion
what are pros and cons of radioaerosols in V/Q: pro: multiple views because aerosolized particles settle

con: no wash out info
what are the minimum requirements for particle size and number in V/Q: 60 000 particles with 10-90 micron size
how do you perform a sestamibi stress cardiac study: 2 ways to do it:
give 8 mCi
image 30 min later for rest
4 hours later give 20 mCi at peak stress
image 30 min later

if low likelihood of disease:
give 30 mCi for stress
- if normal: done
- if abnormal: redo next day with rest/stress
what are the benefits of first pass and MUGA with ventriculography: first pass:
rapid collection
measure at peak exercise
RV better measured

MUGA:
better counts/statistics
how is EF calculated with nucs: (end diastolic counts - end systolic counts)/end diastolic counts
when is MUGA not good to use: with afib or if >5-10% PVCs
what is a normal study for ventriculography: 3 things:
no wall motion abnormality
normal chamber size
EF increases at least 5% with stress

*pearl* a decrease in EF with stress portends a bad prognosis
ddx: increased renal uptake of MDP: NO SCAR

nephrocalcinosis
obstruction
sulfur colloid/thallium
chemo
ATN
radiation
ddx: decreased renal uptake: renal failure
mets
superscan
paget's
ddx: superscan: mets
metabolic
- hyperparathyroidism
- osteomalacia
- renal failure
myelofibrosis
ddx: AVN: ASEPTICLeG

alcohol/anemia
sickle cell/SLE
exogenous steroids
pancreatitis
trauma
idiopathic
caisson's
leukemia/legg-perthes
gaucher's
in what situations is there a high chance of a solitary bone lesion being cancer: spine:
- 40-80% malignant
- higher if in pedicle/body
- lower endplate

pediatrics:
- 55% malignant
how may one image the parathyroid: 3 options:
1. sestamibi
- early: uptake in both parathyroid and thyroid
- delayed: (4-6 hours) thyroid washes out, parathyroid retains

2. sestamibi minus iodine/pertechnetate

3. thallium minus iodine/pertechnetate
- subtracts thyroid - iodine/tech - from thyroid/parathyroid - thal and mibi
what drugs cause uptake on lung gallium studies: BANC

bleomycin
amiodarone
nitrofurantoin
cytoxan
ddx: resting cardiac wall-motion abnormality: contusion
infarct
severe ischemia
non-ischemic cardiomyopathy
valvular heart disease
endocarditis
abscess
what is the appearance of MI on ventriculography: ventricular dilatation
regional wall-motion abnormality
decreased EF

*pearl* EF < 35% in setting of MI = high mortality
ddx: sulfur colloid uptake in lung: DIC
EG
bone marrow transplant
trauma
infection
serum albumin elevation
radiopharmaceutical impurity
liver disease
malignancy
ddx: fatty liver infiltration: POoR ST. JUDE

pancreatitis
obesity
reye's syndrome
steroids
TPN
jejunoileal bypass
ulcerative colitis
DM
ETOH
ddx: solitary splenic lesion on sulfur colloid: infarct
abscess
hematoma
cyst
hemangioma
fibroma
hamartoma
lymphoma
met
ddx: liver hot spot on sulfur colloid: IVC/SVC obstruction
budd-chiari
regenerating nodule
FNH
ddx: absent perfusion to one lung: obstructing mass
post pneumonectomy
congenital heart disease with shunt procedure
sever parenchymal disease
massive pulmonary embolism
ddx: gallium uptake in kidneys: Nucs Scans Are Long And Tiring To Read Particularly Post-Chemo

neoplasm
sarcoid
abscess
liver failure
amyloid
TB/tuberous sclerosis
transplant
radiation
pyelonephritis
PAN chemo
where is gallium normally seen: glands (lacrimal, salivary)
nasopharynx
bone marrow
spleen
neutrophils
colon
thymus
minimal liver
ddx: delayed gastric emptying: DM
drugs
surgery
scleroderma
anorexia
amyloid
high grade obstruction
how do you do a CSF leak radionuclide cisternogram: use In-111 DTPA
inject via LP
image at 4,24 and later if necessary
include abdomen to see swallowed tracer if leaks into nose/mouth
measure pledgets from nose
- ratio of counts/gm nose: counts/gm serum
- if > 3.1 then positive for leak
ddx: meckel's scan uptake: GI DAMIT

GI tract
duplication cyst
AVM
meckel's diverticulum
inflammation (appendicitis)
tumor, hypervascular
ddx: non-visualized thyroid: subacute thyroiditis
IV contrast within 6 weeks
exogenous iodine
PTU, tapazole
foods (turnips, cabbage)
hypothyroidism
ectopic thyroid
surgery/radiation
infiltration
ddx: increased uptake in liver on MDP imaging: hepatoblastoma
hemangioendothelioma
lymphoma
hepatoma
cholangiocarcinoma
mets
aluminum breakthru
recent sulfur colloid study
amyloid
ddx: MIBG uptake: neuroblastoma
pheochromocytoma
carcinoid
medullary thyroid ca
evaluation for right to left shunt: use MAA, IV
look for uptake in brain and kidney
quantify by measuring:
- ROI of lungs
- ROI systemic (whole body - lung)
- divide systemic by systemic + lung
- normal = 1-10%
ddx: cold thyroid nodule: carcinoma
adenoma
colloid cyst
hematoma
focal thyroiditis
fibrosis
parathyroid adenoma
lymphoma
extrinsic mass
ddx: cold defect in vertebral body: hemangioma
met
infarct
XRT
osteomyelitis
brown tumor
what is the formula for I-131 treatment of: - graves - multinodular goitre: graves:
gland wt x 100/% uptake X 160 ug/g

MNG:
gland wt x 100/% uptake x 240 ug/g
what is I-131 treatment for cancer after: - partial thyroidectomy - total thyroidectomy: partial:
60-80 mCI for ablation

total: wait 4-6 weeks then 60-100 mci
follow thyroglobulin q6mo and retreat if increased

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