Terms in this set (111)
differentiate whole body scans (see flip side)
Gallium has light spleen uptake
Octreotide has intense kidney uptake
MIBG has no kidneys (remember we use it to look at adrenals)
Indium vs. Tc99m WBC scan appearance
-renal and GI activity
-lung uptake if imaged at 4 hours
-no renal or GI activity
mechanism of MDP bone scans
-phosphate binds to bone
-distribution based on flow and osteoblastic activity
how is MDP tagged to Tc99m
add free pertechnetate to stannous ion (to reduce it)
it will then bind to MDP
what causes free Tc when preparing MDP scans
air in the syringe (oxidation)
not enough stannous ion
highest dose organ with MDP and F-18 bone scans
marked bone scan uptake along cranial sutures
focal breast uptake on bone scan
marked renal cortex uptake on MDP bone scan
liver uptake on bone scan
cancer, amyloid, liver necrosis
spleen uptake on bone scan
infarcted spleen (sickle cell)
sacral insufficiency fracture on bone scan
muscle uptake on bone scan
preferred test for bones mets from neuroblastoma
MIBG with I-123/131
hypertrophic osteoarthropathy on bone scan
"tram line uptake" along periosteum
next step? chest CT for lung cancer
Pagets on bone scan
enlarged hot long bone or hemipelvis
"mickey mouse" vertebrae (body and post elements)
early and late AVN on bone scan
Early and late are cold
middle may be hot (from repair)
osteoid osteoma on bone scan
BENIGN BONE LESIONS ON BONE SCAN
HOT or COLD?
bone cyst without fracture
giant cell tumor
all hot except bone cyst without fracture
decreased soft tissue uptake vs. increased soft tissue uptake on bone scan
increased soft tissues
-metabolic superscan (kidney disease)
skull hot on metabolic (from PTH)
causes of triple phase positive bone scan
RSD or CRPS
preferred nucs agent for spine osteomyelitis
Gallium (In-WBC can be false negative)
which patients sometimes require a 4th phase bone scan (24 hours)?
give time for soft tissue tracer to clear
critical organ of In-WBC
agent for V/Q perfusion portion?
biologic half life of the agent?
4 hours biologic half life
ventilation with Xenon-133
physical vs. bio half lives
when doing V/Q, is xenon of MAA done first?
physical: 5.3 days
bio: 30 seconds (exhaled)
ALWAYS do XENON first, energy is around 80kEv (will be overpowered by Tc99 if Tc done first)
allows for different views
tends to clump
DO BEFORE THE PERFUSION
size of V/Q scan MAA particles
when is number of particles reduced
10-100 micrometers (any bigger will block arterioles)
reduce for kids and pregnancy, or R>L shunts, or pulm HTN
multiple scattered hot spots on V/Q perfusion
clumped MAA, from tech drawing back blood into the syringe before injection
liver uptake on Xenon-133 ventilation
unilateral whole lung perfusion defect
get cross sectional imaging to exclude large central obstructing cancer
technically speaking this is low probability for PE
what is it used for?
used for tumor/inflammation/infection
iron analogue (acute phase reactant)
half life 78 hours
peaks at 100, 200, 300, 400 (technically 93, 184, 300, 393)
critical organ is the colon
radiotracer uptake in lacrimal glands
typical of gallium scan
sarcoidosis on gallium scan
hilar and paratracheal uptake ("lambda")
"panda sign" - lacrimal glands, parotids, nasopharynx
-also seen with sjogrens or treated lymphoma
Gallium appearance with PCP vs. Kaposi sarcoma
-gallium negative, but thallium positive
preferred nucs agent for abdominal or pelvic infections
gallium will have decreased sensitivity because of normal GI uptake
I-131 vs. I-123 vs. Tc99m
-high energy (364 keV) - think "1 year is 365 days"
-8 day half life
-ideal energy (159 keV)
-decays via electron capture
-13 hour half life
-6 hour half life
when is Tc99m preferred over iodine for thyroid imaging
recent IV contrast or thyroid blocker medication
how long is breastfeeding held for thyroid imaging agents
-NO MORE BREASTFEEDING
-2 to 3 days
what medications artificially lower thyroid uptake on nucs
appearance on nucs
typical treatment dose I-131
hot homogeneous gland
high uptake (at times >75% at 24 hours)
15-20 mCi I-131
normal thyroid uptake at 4 and 24 hours
4 hours - 5-15%
24 hours - 10-35%
toxic multinodular goiter
typical treatment dose I-131
uptake around 35%
heterogeneous with hot nodules
treat with 30 mCi I-131
heterogeneous cold gland with cold areas
clinically hyperthyroid ... viral prodrome
clinically like a graves, with diffusely low uptake (all hormones already released)
thyroid uptake >5% after thyroidectomy, but prior to I-131 treatment
send back to surgeon
can treat when <5%
how is TSH increased before I-131 treatment
stop thyroid hormone
dosing for I-131 cancer treatment
local - 100mCi
local nodes - 150mCi
distal mets - 200mCi
which I-131 patients need to be admitted
limit is 7mR/h at 1 meter
residual activity cutoff is 33mCi
side effects of I-131 treatment
pulmonary fibrosis if diffuse lung mets are treated
salivary gland damage
contraindications to I-131 therapy
what do you do with dialysis materials for I-131 patient
fluid can be discarded
dialysis tubing must be stored to decay
techniques for nuc med parathyroid imaging
dual phase (early and delyaed)
-parathyroid adenoma persists on delays (thyroid disappears)
-subtract I-123 from sestamibi
agents that cross blood-brain-barrier
agents used for neuroimaging which dont cross
DON'T CROSS (lipophobic)
nucs seizure focus localization
need lipophilic agent (HMPAO or ECD)
-inject when seizing
HOT area during ictal
COLD during interictal
how is it made?
made in cyclotron
decays via electron capture
half life of 73 hours
energy 69 and 81 keV
behaves like potassium (taken up by living cells Na/K pump)
Thallium properties ... hot or cold?
only accumulates in living tissue (Na/K pump)
nuclear diagnosis of brain ischemia
1. do SPECT
2. give Diamox
3. repeat SPECT
worsening ischemia should be seen with diamox (like a brain stress test)
-next step: angiography and possibly treat it
nuclear imaging features of dementia?
dementia with lewy body?
-low temporoparietal activity
-random low activity
-occipital low activity
-cingulate island sign (IMAGE)
-low activity in the caudate and putamen
nuclear test for parkinsons
ioflupane I-123 scan
crossed cerebellar diaschisis
issue in one lobe turns off cerebellum of other lobe
-related to cortciopontine-cerebellar pathway
how is NPH diagnosed?
administer via lumbar puncture
4hours: around sylvian fissures and cisterns
24 hours: around convexities (not lat vents)
in lateral ventricles (not over convexities) at 24 hours which persists
how is imaging for CSF leak performed
pack pledgets in the nose
administer a CSF tracer (ex. In-111 DTPA)
wait 1-3 hours
compares counts on pledgets to serum (ratio > 1.5 is positive)
pretreatment considerations before gastric emptying scan
STOP prokinetics (reglan), erythromycin
STOP opiates for 2 days
STOP anticholinergics for 2 days
tagging RBC for GI bleed scan
hybrid in vivtro?
-stannous ion injected into patient
-stuff binds, lots of free tech
-affected by heparinized tubing and recent IV contrast
-stannous into patient
-15 mins later draw blood
-tag it outside and reinject
-all done outside of body
pertechnetate used (taken up by gastric mucosa)
30 mins of dynamic imaging
do the study when NOT BLEEDING
STOP H2 blockers
gallbladder rim sign (HIDA)
implies bad acute cholecystitis, may be gangrenous
doses for CCK and morphine for HIDA
CCK: 0.02 mcg/kg over 60 mins
morphine: 0.02 mg/kg over 30-60 mins
how is the liver primed for HIDA to rule out biliary atresia
phenobarbital to induce liver
"5 for 5 keeps the liver alive"
5mg/kg x 5 days, then scan
Liver masses on nucs
what is HOT on RBC scan?
what is HOT on gallium scan?
what is HOTon Xenon?
what is HOT on sulfur colloid?
RBC - hemangioma
gallium - HCC or abscess
xenon - steatosis
sulfur colloid - FNH
cause of lung activity in sulfur colloid
excess aluminum in the colloid
RENAL SCAN physiology of ...
-better for poor renal function tests
-decreased uptake and flow of stenotic side
-tracer retention on stenotic side (looks like obstruction curve)
18-FDG for PET
how is it made?
physics of this and energy?
beta positive emission
positron emitted, collides with electron which gives off two 511 keV photons
diffuse muscle uptake on PET
ideal PET imaging time after chemo? and XRT?
2-3 weeks post chemo
8-12 weeks post XRT (avoid false positives)
how is SUV calculated for PETs
SUV = FDG concentration at a time/(dose/body weight)
tumors that are PET cold?
peritoneal bowel implants
cold ground glass nodule on PET
cancer ... HOT is likely infec/inflamm
how is it made?
electron capture decay
67 hours half life
173 and 247 keV ("175 and 250")
what is its primary use?
always give Lugol's (SSKI) first to block thyroid
used for neuroblastoma met staging
can use for pheochromocytoma
REMEMBER KIDNEYS ARE COLD (so you can see adrenals)
what medications interact with MIBG scan?
calcium channel or beta blockers
classic location of brown fat on PET
around the shoulders/trapezius
what is it labeled with?
which suspected tumor may require supplementation with D50 or glucose?
critical is spleen
which test is preferred - MIBG or octreotide?
non-functional islet cell tumor?
medullary thyroid cancer?
carcinoid - octreotide
gastrinoma - octreotide
pheochromocytoma/paraganglioma - MIBG for adrenal, extraadrrenal with octreotide
non-functional islet cell tumor - FDG-PET
medullary thyroid cancer - octreotide or PET
neuroblastoma - MIBG
agent and radionuclide?
when is it used (clinical scenario)?
where does it localize?
Capromab pendetide (monoclonal Ab for PSA membrane antigen)
labeled with In-111
rising PSA with negative bone scan, localizes to soft tissue mets
critical organ is liver
Tc99m sulfur colloid
inject at site of cancer or in breast, and follow to sentinel node
particles are very smaller (smaller than V/Q)
-200 nanometers or less
molecular breast imaging
Tc99m sestamibi ... 20-30 mCi
image during proliferative phase of cycle, image 20 mins after injection
-small or deep lesions
-lesions in medial breast
-lesions overlying the heart
preparation for nuclear cardiac stress
no eating for 4 hours
STOP calcium channel, beta blockers, nitrates for 24 hours
NO CAFFEINE (offsets effects of pharmacologic stress agents)
LBBB false positive artifact on stress perfusion
reversible perfusion defect at the anteroseptal region (can't evaluate this area for true ischemia)
-related to septum not relaxing during diastole
LV cavity larger on cardiac stress imaging
transient ischemic dilatation
correlate for 3 vessel disease
stunned myocardium vs. hibernating on nucs and PET
-looks like infarct
-decreased perfusion and contractility
Hibernating is HOT on FDG-PET
thallium viability imaging
hibernating looks like infarct on perfusion stress test
on thallium ... tracer redistributes by 24 hours
cold on day 1, hot on day 2 (essentially the opposite of normal stress test)
how is EF calculated?
what causes falsely low or high calculated EF?
Tc99m labeled RBC
gated imaging, compare end diastole and end systole
EF = (EDV/ESV) / (EDV - background)
False LOW: LV measurement overlaps LA
False HIGH: wrong background ROI
-such as over spleen
which radionuclides are made in a generator?
What is Rubidium-82 used for?
can be a cardiac perfusion agent, is expensive
short half life (75 seconds)
side effect of adenosine
Strontium-89, Samarium-153, Radium-223
bone marrow toxicity?
half life of radium?
-most marrow toxic
-bone mets tx
-beta emitter, few gamma rays (~100keV)
-medium marrow toxic
-bone mets tx
-less marrow toxic
-improves survival with prostate mets
-half life is 11 days
risk of treatment?
energies and emission?
half life 2.67 days
beta emitter ... 175 and 185 keV
dose ~100 Gy
particles 20-40 micrometers
risk of lung fibrosis if shunt too big on mapping (shunt > 10% may be an issue)
radioimmune therapy for lymphoma
pretreatment for mapping?
map with In-111
treat with Y-90
target antibody to CD-20 receptors on B-cells
altered bio distribution is contraindication
-lung uptake at days 2-3
-kidneys>liver day 3
-fixed bowel activity
-uptake > 25% in marrow
pretreat with rituximab to block native CD20 receptors when mapping
which radionuclides have a 3 day half life
critical organ of ...
energy and half life?
which meds can be administered to increase sensitivity of each scan?
HIDA for biliary atresia?
HIDA for cholecystitis?
Renal scan for renal artery stenosis
-cimetidine or glucagon
HIDA for atresia
-phenobarbital ("5 for 5" - 5/MG/KG FOR 5 DAYS)
HIDA for chole
-morphine (0.04 mg/kg)
Renal for RAS
gallium imaging for neoplasm ....
when are the images normally taken
3 day half life
images taken around 48-72 hours
typical gallium dose for infection or cancer imaging?
INFECTION - 5 mCi
CANCER - 10 mCi
PIOPED for triple matched V/Q defect ...
in lower lobes?
in right middle?
in upper lobes?
LOWER - intermediate prob
MIDDLE OR UPPER - low prob
radiotracer used for testicular imaging
typical dose for sulfur colloid liver/spleen scan?
when is imaging done on liver/spleen scan
which organ is hotter typically?
LIVER > SPLEEN UPTAKE
typically ~ 5 mCi
image at 20 mins
how far from the patient is the thyroid uptake probe placed for the 24 hours measurement
25-30 cm from neck to crystal