Nuclear Medicine Flashcards
1
Q
meckel diverticulum scan
A
Tc99m pertechnetate
2
Q
FNH scan
A
- sulfur colloid
- HIDA (Tc99m iminodiacetic acid analog)
3
Q
what is used for HIDA
A
- Tc99m disofenin
- Tc99m mebrofenin
4
Q
pulmonary radiotracers
A
- perfusion: Tc99m macroaggregated albumin MAA
- ventilation: Xenon 133, Tc99m DTPA, Technegas (T99m)
5
Q
1/2 life T99m
nrg
A
6 hours
low nrg 140 kev
6
Q
1/2 life I 123
nrg
A
13 hours
low nrg 159 kev
7
Q
1/2 life I 131
nrg
A
8 days
high nrg 365 kev
8
Q
test for pNET
A
In-111 octreotide
Dotatate
9
Q
test for splenule
A
T99m sulfur colloid
T99m damaged RBC
10
Q
1/2 life gallium 68
A
68 minutes
11
Q
1/2 life Fluorine 18 (FDG)
nrg
A
110 minutes
high nrg 511 kev
analog sugar
12
Q
1/2 life gallium 67
A
3.3 days (78 hours)
nrg peaks are medium
100 (40%), 200 (20%), 300 (20%), 400 (5%)
analog is iron
13
Q
1/2 life sulfur colloid
A
2-3 minutes (Tc99m)
14
Q
1/2 life In-111
A
67.2 hours
15
Q
gallium 67 > indium 111 WBC scan when?
A
disc space infection
16
Q
medication to stop before I-123 MIBG
A
TCA, CCB, labetalol, sympathomimetics, reserpine
17
Q
what is yttrium-90 ibritumomab (zevalin)
A
murine anti-CD20 monoclonal antibody conjugated to the radioisotope yttrium-90
for non-hodgkins lymphoma (follicular)
18
Q
Tc-99m sulfur colloid scintigraphy is taken up by which cells?
A
reticuloendothelial - liver, spleen, bone marrow
19
Q
Nuclear Regulatory Commission (NRC) dose limits for annual whole body occupational exposure
A
50 mSv = 5 rem
20
Q
radiotracer for nuclear medicine cisternogram
A
In-111 DTPA
administered into CSF via lumbar puncture
21
Q
how frequent must a radiation survey be performed in areas of radionuclide waste storage?
A
weekly
22
Q
cold lesions on MDP bone scan
A
late radiation tx changes/osteitis (segmental)
early osteonecrosis
infarction (very early or late)
anaplastic tumor (renal, thyroid, neuroblastoma, myeloma)
artifact from prosthesis, pacemaker, spine stimulator
hemangioma (variable**)
bone cyst (without fracture)
mature heterotopic ossification
23
Q
why do you do bone scan for heterotopic ossification
A
to see if it’s mature (cold) for surgical resection (if painful or joint mobility affected)
- follow active HO (hot) until mature
24
Q
feature of osteomalacia best seen on a bone scan
A
pseudofractures/Looser zones
- contain fibrous tissue & poorly mineralized callus
- ribs, femoral neck, pubic rami, axillary margins of scapulae
(other features of demineralization & coarsened trabeculae better seen on radiography)
25
annual limit of radiation exposure to the public as defined by the NRC
1 mSv = 100 mrem
26
bone scan with tracer in stomach, thyroid, or salivary glands: what's the cause?
free pertechnetate
- d/t not enough stannous ion (during preparation from kit with MDP & stannous ion) or
- d/t air in vial or syringe causing oxidation
thin layer chromatography (TLC) used to identify free pertechnetate in the presence of a radiopharmaceutical
27
causes of super scan
diffuse skeletal metastatic activity (MC breast, prostate)
metabolic bone pathology (hot skull)
- hyperparathyroidism
- renal osteodystrophy
- Paget
- severe thyrotoxicosis
28
how do you block the thyroid gland from unintended radiation from unbound I-123 or I-131 in a MIBG scan?
Lugol's iodine, perchlorate, or SSKI (super saturated potassium iodide)
29
normal biodistribution of MIBG
liver, spleen, colon, salivary glands, heart
+/- adrenals faintly
+/- brown fat (around shoulders/traps), which has sympathetic innervation
kidneys & bone NOT seen
thyroid is NOT seen if pretreated with Lugol's iodine
30
what is a MIBG scan for?
any catecholamine producing tumor (analog of noradrenaline)
- neuroblastoma (classic)
- pheochromocytoma
- paraganglioma
- carcinoid
31
LVEF equation for MUGA
(end diastolic counts - end systolic counts)/(end diastolic counts - background)
32
cause of false high EF on MUGA
high background
| e.g. wrong background ROI over spleen: over subtraction
33
cause of false low EF on MUGA
low background
inclusion of left atrium counts (e.g. if LA enlarged)
erroneous LAO view: can cause overlap of LV with LA, RV or great vessels
34
dose for radioactive ablation of hyperfunctioning thyroid nodule
empiric dosing with 30 mCi of I-131 sodium iodide
- hyperfunctioning adenomas are difficult to treat and may not respond to smaller doses
- more than 15 mCi for Graves
35
dose for radioactive ablation for Graves disease
15 mCi
36
lymphoscintigraphy indications
identifying sentinel lymph node
- node that receives afferent drainage directly from a primary cancer
- melanoma with lesion 1-4mm deep, breast ca
functional evaluation of lymphatic channels
- points of blockage
- lymphedema
37
how long must a licensee maintain records of the disposal of licensed materials according to the NRC?
3 years
record must include:
- date of the disposal
- survey instrument used
- background radiation level
- radiation level measured at surface of each waste container
- name of individual who performed survey
38
radiotracers with normal biodistribution in liver, spleen and bone marrow
In-111 WBC
| Tc-99m sulfur colloid
39
radiotracers with normal biodistribution in liver, spleen, kidneys, bowel and urinary bladder
In-111 pentetreotide
40
I-131 whole body scan post radioactive iodine ablation + diffuse uptake in lungs
iodine-concentrating metastases
41
I-131 whole body scan + uptake is seen in liver
post radioactive iodine ablation scan
42
annual limit of occupational radiation exposure to ocular lens as defined by the NRC
150 mSv = 15 rem
43
annual limit of (occupational) total equivalent organ dose as defined by the NRC
500 mSv = 50 rem
44
annual limit of (occupational) total equivalent extremity dose as defined by the NRC
500 mSv = 50 rem
45
annual limit of total dose to embryo/fetus over entire 9 months as defined by the NRC
5 mSv = 0.5 rem
if fetus already got 5 mSv at time of declaration, NRC states you can get 0.5 mSv more for remainder of pregnancy
46
unit conversion rad, rem, Gy, mSv
1 rad = 1 rem = 0.01 Gy
| 1 mSv = 100 mrem = 0.1 rem
47
extraosseous uptake in heart on bone scintigraphy
amyloidosis (if diffusely in LV myocardium)
| prior myocardial infarction 2/2 to microcalcifications
48
uptake in skull sutures on bone scintigraphy
can be normal
| renal osteodystrophy if marked
49
extraosseous uptake in breast on bone scintigraphy
normal if mild diffuse uptake in younger women
| cancer if focal uptake
50
extraosseous uptake in renal cortex on bone scintigraphy
hemochromatosis if renal cortex hotter than adjacent lumbar spine
chemotherapy
otherwise normal
if you can't see kidneys, think super scan
51
extraosseous uptake in kidneys diffusely on bone scintigraphy
chemotherapy
| urinary obstruction
52
extraosseous uptake in liver on bone scintigraphy
too much aluminum contamination in Tc
cancer: HCC, mets
amyloidosis
liver necrosis
53
extraosseous uptake in spleen on bone scintigraphy
auto-infarcted spleen in sickle cell patients
| - will also have scattered hot and cold areas from multiple bone infarcts
54
extraosseous uptake in lung on bone scintigraphy
```
heterotopic calc'n (dystrophic or metastatic)
osteosarcoma mets, primary lung tumor
radiation changes
sarcoid, berylliosis
alveolar microlithiasis
Wegener/GPA
fibrothorax
```
55
extraosseous uptake in muscle on bone scintigraphy
localize to injured skeletal muscle
| rhabdomyolysis if diffuse bilateral quadriceps, calves, shoulders in marathon runner or military recruit
56
diffusely decreased skeletal uptake on bone scintigraphy
free Tc
| bisphosphonate therapy
57
rim sign
curved area of increased hepatic activity along GB fossa on HIDA scan
- suggests more significant cholecystitis
- in emphysematous cholecystitis, 20% of gangrenous cholecystitis
- mechanism: result of inflammation causing regional hepatic hyperemia, with more radiopharmaceutical delivered to this area
58
complex regional pain syndrome on bone scintigraphy
scan with 3 phase scan:
↑ uptake in affected limb on flow & blood pool + diffusely periarticular ↑ uptake on delayed phase
- ↑ uptake on all 3 phases: seen in <50%, but highest dx accuracy
- infxn & arthritis: false-positive findings
59
MUGA radiotracer
Tc99m labelled RBC
60
octreotide vs MIBG
MIBG does not have intense renal activity
61
hallmark location of PET hypometabolism in Lewy body dementia
occipital lobes
62
MC pattern of loss seen with Parkinson’s disease in dopamine transporter SPECT imaging
loss of activity in the putamen first before the caudate
63
Deauville criteria lymphoma
1: no uptake
2: =< mediastinum
3: > mediastinum, =< liver
4: > liver
5: >> liver or new lesions
X: new areas uptake unlikely lymphoma
64
parathyroid adenoma studies
1) single tracer dual phase sestamibi
2) dual tracer sestamibi & I123 (or Tc99m pertechnetate)
3) 4D CT
65
difference between HMPAO and ECD
HMPAO: fast washout, uptake favours frontal lobe, thalamus, cerebellum
ECD: slow washout, better background clearance, no intracerebral redistribution, favours parietal & occipital lobes
66
thallium:
- production
- energy decay
- half life
- major emissions
- daughter product
- cyclotron
- electron capture
- 3 days (73 hours)
- 69 & 81 keV
- mercury 201
67
normal thallium distribution
- thyroid & salivary glands
- lungs & heart
- skeletal muscle
- liver & spleen
- bowel
- kidneys & bladder
68
stop & maintain what drugs for gastric emptying?
STOP: 2 days before
- prokinetics (ex metoclopramide)
- opiates
- anticholinergic/antispasmodic (ex donnatal)
KEEP:
- serotonin receptor antagonist (ex zofran)
69
drugs for HIDA scan
CCK (GB contract): 0.02 microgram/kg over 60 mins
morphine (sphincter oddi contract): 0.02 mg/kg over 30-60 mins
70
drugs causing cholestasis with delayed excretion (HIDA)
- chlorpromazime
- erythromycin
- birth control (estrogen)
- anabolic steroids
- +/- statins
71
colloid shift
- what is it
- what causes it
- normally 85% sulfur colloid to liver (10% spleen, 5% bone marrow)
- change in uptake to spleen and bone
- diffuse hepatic dysfunction
- portal HTN
- hypersplenism
- bone marrow activation
specifically: cirrhosis, diffuse liver mets, diabetes, blunt splenic trauma.
72
renal function radiotracers
```
Tc DTPA: almost all filtered, for function
Tc MAG3: secreted, for renal plasma flow, better for poor renal fxn
Tc GH (glucoheptonate): filtered, structural or functional imaging
```
critical organ = bladder for all
73
renal structure radiotracers
Tc DMSA: binds cortex, cleared slowly, kidney critical organ
| Tc GH: binds & filtered, bladder critical organ
74
SUV calculation
SUV = FDG concentration at time T/(dose/body weight)
75
FDG uptake
- FDG into cells by GLUT1 transporter
- phosphorylated by hexokinase to FDG6 phosphate
- locked in cell
N biodist'n = brain, heart, liver, spleen, GI, blood pool, salivary glands, testes
critical organ = bladder
76
indium 111
1/2 life
photopeaks
normal uptake
1/2 life - 67 hours
peaks: medium nrg 173 & 247 kev
uptake: thyroid, liver, GB, spleen, kidneys, bladder, GI
- early imaging avoids bowel activity
77
medications to hold pre MIBG
- CCBs
- labetalol
- reserpine
- TCAs
- sympathomimetics
78
MIBG scan
- bound to I123 (better quality), I131 (longer 1/2 life)
- block thyroid w/ lugol's, perchlorate, SSKI
- dist'n: liver, spleen, colon, salivary +/- adrenals
79
scans for MIBG vs octreotide
MIBG: non malignant (adrenal) pheo, neuroblastoma
octreotide: carcinoid, gastrinoma, extra adrenal pheo, paraganglioma, medullary thyroid ca
80
critical organ for indium:
prostascint
WBC
octreotide
- liver
- spleen
- spleen
81
lymphoscintigraphy agent
10-50 nm (<0.2 microns/200nm) Tc99m sulfur colloid
82
LBBB classic artifact on myocardial perfusion
reversible perfusion defect at septum
83
Y90 1/2 life, emissions, particle size, radiation dose
1/2 life 2.67 days
emissions: 175 & 185 kev
particle size: 20-40 micrometre
dose: 100-1000 Gy, at least 70 for monotherapy success
84
protocol for zevalin radioimmune therapy
- used for refractory NHL
- give rituximab to block CD20 in circulating B cells & optimize biodist'n
- give In111 to assess dist'n
- ok dist'n give ibritumomab tiuxetan (zevalin) w/ Y90
85
altered dist'n of In 111 for NHL RIT
- uptake in lungs > heart day one, or >liver day 2 & 3
- uptake in kidneys > liver day 3
- uptake in bowel fixed and/or > liver
- uptake bone marrow >25%
don't give if plts <100k
86
xenon 133 1/2 life
| nrg
physical 1/2 life 125 hours
biologic 30 seconds
low nrg 81 kev
87
scan for neuroblastoma bone mets
I123 and I131 MIBG
88
bone uptake on MIBG, I131, octreotide:
| normal or abnormal
abN
| concerning for mets
89
bone scan or skeletal survey for:
blastic mets
lytic mets
myeloma
blastic - bone scan
| lytic & myeloma - skeletal survey
90
```
breastfeeding recommendations for:
Tc99m
I123
I131
FDG PET
```
Tc99m resume in 12-24 h
I123 resume in 2-3 days
I131 pump and dump
FDG PET continue; however, can get some external radiation from the skin so locally suggest no close contact 1st day
91
normal thyroid uptake values
4-6 hours
24 hours
4-6 hours: 5-15%
24 hours: 10-35%
correction of neck - thigh counts
92
max radiation dose worker/year
5 rem (50 mSv)
93
osseous radionuclide agent that can be imaged:
samarium 153 (alpha and beta emission)
strontium 89, phosphate 32 beta only
radium 223 alpha only
94
perfusion defect artifacts on cardiac imaging
diaphragm attenuation: inferior (RCA)
breast: anteroseptal apex (LAD)
no associated wall motion abN
95
scans for neuroblastoma
bone scan can show mass
| MIBG better for bone mets, combined can be better
96
hot lacrimal glands
- gallium 67
| - free Tc99m pertech (higher count/quality, spleen uptake)
97
decrease scatter
1) collimator: decrease off axis, increase resolution, but decrease sensitivity
2) pulse height analyzer: select narrow range
3) time of flight & coincidence detection: on PET
98
cardiac uptake
- sestamibi
- thallium
- MIBG
99
super hot spleen
1) tagged WBC (In111, Tc99)
2) octreotide (+ kidney, no bone)
3) sulfur colloid if colloid shift (+ bone)
100
high cardiac & high renal
1) Tc99m sestamibi
| or thallium but unlikely to have whole body scan
MIBG cardiac, no kidney
101
how often to check accuracy of dose calibrator?
| how often to calibrate geiger mueller counter?
annually
102
how often is linearity checked on a dose calibrator?
quarterly
103
sestamibi radionuclide?
Tc99m
