nuclear Flashcards
Cardiac uptake on a scan - not PET
MIBG, sestamibi, thallium
MIBG vs. Octreotide
MIBG and octreotide can both localize to neuroendocrine tumors (pheochromocytoma, paraganglioma, **neuroblastoma, and carcinoid). In almost all cases, MIBG is the way to go. The exceptions are **carcinoids and extraadrenal pheochromocytomas, gastrinoma (according to Gainesville)
what nuclear scan to look for PCP pneumonia
Gallium 67
What is thyrogen and when is it used in nuc med?
a highly purified recombinant form of human thyroid stimulating hormone (TSH), given by injection prior to I-131 study as an alternative to going off thyroid hormone
normal distribution of octreoscan?
Liver, spleen, kidneys, thyroid, GB, bladder, Normal pituitary gland
What is MIBG structurally similar to?
Norepinephrine - thus scanning for Pheos, **neuroblastoma, and paragangliomas
half life of Tc-99m
6 hours
In-111 half life
2.8 (3) days
In-111 WBC scan normal distribution
liver, spleen, bone marrow (NO urinary or GI tract activity!)
I-123 half life
13h
Iodine scan normal distribution
thyroid gland (target organ) nasopharynx salivary glands stomach (target organ) colon bladder (target organ) lactating breasts
I-131 half life
8 days
What’s the prep before I-131 scanning?
D/c thyroid hormone or us thyrogen
octreoscan - what radiopharmaceutical?
In-111
Octreoscan - what’s it used for?
Neuroendocrine tumors: carcinoid tumour, paraganglioma(s), glomus jugulare/tympanicum/vagale,
carotid body tumour, pheochromocytoma, small cell lung cancer, pituitary adenoma, neuroblastoma, medullary thyroid carcinoma, islet cell tumour of pancreas
octreotide is an analogue of what?
somatostatin (thus useful for neuroendocrine tumors)
MIBG - what radiopharmaceutical?
I-123
MIBG - used for what?
*phaeochromocytoma.
*neuroblastoma
esthesioneuroblastoma
carcinoid tumour
paraganglioma
phaeochromocytoma
medullary thyroid carcinoma
ganglioneuroma
ganglioneuroblastoma
MIBG normal distribution
liver spleen heart(!) salivary glands urinary bladder gastrointestinal tract (faint) lungs brown fat
FDG - half life
109 minutes
Gallium-67 - half life
78 hours (think 67, 78)
Ga-67 normal distribution
lacrimal glands!
liver (site of highest uptake)
bone marrow
spleen
GI tract
salivary glands
nasopharynx
kidneys and bladder in the first 24 hours (only!)- faint uptake can still be normal for up to 72 hours
breast uptake (especially in pregnant and lactating women)
mild diffuse lung uptake at 24 hours or less
What’s a superscan in a bone scan? What are causes?
intense symmetric activity in the bones with diminished renal and soft tissue activity
diffuse metastatic disease (prostatic, breast cancer, TCC, lymphoma
metabolic bone diseases (renal osteodystrophy, hyperparathyroidism -often secondary hyperparathyroidism-, osteomalacia (will involve distal skeleton smoother uptake)
myelofibrosis / myelosclerosis
mastocytosis
widespread Paget’s disease
sestamibi - normal distribution
thyroid, parathyroid, heart
sestamibi radiopharmaceutical
Tc 99m
sestamibi - used for?
parathyroid adenoma detection cardiac imaging (MIBI)
sulpher colloid - what radiopharmaceutical?
Tc 99m
sulpher colloid normal distribution
spleen, Kupffer cells in the liver and a small proportion by bone marrow
Tc-99m pertechnetate - used for?
Meckel’s scan (also thyroid in pediatrics, parathyroid, testicle)
what’s a bone scan’s pharmaceutical?
Tc 99m MDP
What is lung perfusion imaging done with?
Tc 99m MAA
Tc brain scan radiopharmaceutical?
HMPAO
pertechnetate normal distribution
stomach, thyroid, salivary glands, (testicles)
Renal imaging agents:
What’s each for?
MAG3 - good for poor renal function pts (tubular excretion)
DTPA - generally used, need good renal fctn (glomerular filtration)
DMSA - cortical imaging (kids mostly)
What instructions to I-131
drive home alone/sit in rear seat if ride separate bedroom & bathroom flush twice don't share phone store trash/laundry flush tissues
What’s the allowed dose to the Public
5 mSv/year
Lung uptake on bone scan - what is it? Caused by?
Metastatic calcification or pulmonary microlithiasis
met calc: caused by same things as medullary calcinosis: hyperparathyroidism, renal tubular acidosis, milk-alkali, hyper vit. D, sarcoid, diffuse tumors (esp. myeloma)
Ddx for elevated I-123 uptake in thyroid
IF TSH is low (supressed): Graves
Ddx for low I-123 uptake in thyroid
IF TSH is low (supressed): Subacute or postpartum thyroiditis, exogenous (factitious),
WT@#$??: brain and heart, sharp images
FDG PET
WT@#$??: brain and heart, not so sharp
whole body HMPAO
WT@#$??: heart, no brain:
thallium, sestaMIBI, I-123 MIBG
WT@#$??: bone marrow, gut, lacrimal glands (no heart or brain)
Gallium
WT@#$??: liver, spleen, kidneys (no heart or brain)
octreotide
WT@#$??: spleen, liver, bone marrow (no heart or brain)
WBC
WT@#$??: shitty images, no heart or brain
I-131
What’s the full name of a Tc labelled WBC scan?
Tc-99m HMPAO WBC
How do you diagnose infected prosthesis in nucs?
Start with a bone scan - if normal, high negative predictive value
Do sulfur colloid
Do WBC scan - if WBCs go where there’s no marrow, it’s an infection
Dx for normal bone scan with known lytic lesions: in adult? in child?
Older: myeloma/plasmacytoma, RCC
Young: LCH
Abdominal tumor in a child visible (uptake) on bone scan
Neuroblastoma - look for mets
95% take up MDP
75% calcify
How long does radioactive material need to be stored before discarding?
10 half lives (I-131 would be 3 months)
then survey to ensure it’s not above background
What’s the generic (acronym) response to a radioactive spill?
SWIM: Secure the area Warn others Identify the spill/agent Maintain the area (until help arrives)
Heart and liver uptake on bone scan
amyloidosis (also kidneys, but hard to tell since already hot on bone scan)
Radioactive spill categories - discuss
Major spill: >100 mCu or potential for airborne (any I-131), large area, uncontrollable, or catastrophic malfunction of radiation producing equipment
Minor spill: small quantity, not meet criteria for major, recognized and should not result in personnel contamination
What causes “ring artifact” in SPECT?
Center of rotation error
Non-uniform gamma camera
Steps to receive a radioactive package:
Survey, check for damage, wipe test
must be done w/in 3 hours during working hours, w/in 18 hours non-working
features of Lewy body dementia:
occipital abnormality (not seen in Alzheimer’s), visual hallucinations
2nd most common dementia
some think related to Parkinson’s
Absent perfusion to one lung on VQ
If vent is also abnormal: Swyer James, mass, mucus plug
If vent is normal: pulmonary mass, PA agenesis, PE, and fibrosing mediastinitis
unilateral focal spine uptake, young pt
pars fracture, ask for Hx, do SPECT
why would you see heterogeneous liver uptake on bone scan?
liver mets - acute cellular death or calcification in mucinous mets
How often do you have to do wipe tests on the patient waiting area?
Weekly. at least 5 spots per room.
Daily, you survey with the survey meter.