NUKES Flashcards
Tc-99m
“low” 140 keV; 6 hours
Iodine - 123
“low” 159 keV; 13 hours
Xenon - 133
“low” keV 81; 125 hours or 5.3 days (biologic 1/2 life of 30 seconds)
Thallium - 201
Potassium analogue; “low” x-rays from daughter Hg 201 at 68-82 keV (71 or 77 keV), 135 keV (2%), 167 keV; half life 73 hours
Indium - 111
“medium” 173 keV, 247 keV; 67 hours
Gallium - 67
Iron analogue; 93 keV (40%), 184 keV (20%), 300 keV (20%), 393 (5%); half life 78 hours
Iodine - 131
“high” 365 keV, 8 days
Fluorine - 18
“high” 511 keV, 110 mins
Strontium 89 half life
50.5 days (14 days in bone)
Samarium 153 half lif
46 hours
Radium half life
11 days
Yttrium 90 half life
64 hours
Rubidium 82 half life
75 seconds
Nitrogen 13 half life
10 mins
Critical organ Tc-MDP
Bladder (some say bone)
Critical organ Tc - sulfur colloid (IV)
Liver
Critical organ Tc - sulfur colloid (oral)
proximal colon
Critical organ Tc - pertechnetate
stomach > thyroid (some sources say colon)
Critical organ Tc - sestamibi
proximal colon
Critical organ Tc - heat treated RBC
Spleen > heart
Critical organ Tagged RBC - MUGA
Heart
Critical organ Tc - MAA
Lung
Critical organ Tc- DMSA
Renal cortex
Critical organ Tc - MAG 3
Bladder
Critical organ DTPA
Bladder
Critical organ I-123 MIBG
Bladder (some say adrenal medulla)
Critical organ I-131 MIBG
Liver (some say adrenal medulla)
Critical organ I-131, I-123
Thyroid
Critical organ In-111 WBC
spleen
Critical organ In-111 ProstaScint
Liver
Critical organ In-111 Octreoscan
Spleen
Critical organ Thallium 201
renal cortex
Critical organ F18 FDG
Bladder
Critical organ Gallium-67
Distal colon
HIDA
GB wall
Mechanism of localization: Tc - sestamibi
passive diffusion (lipophilic diffusion)
Mechanism of localization: Tc - tetrofosmin
passive diffusion (lipophilic diffusion)
Mechanism of localization: Tc - HMPAO
passive diffusion (delivery flow related - then diffuse into brain)
Mechanism of localization: Tc - ECD
passive diffusion (delivery flow related - then diffuse into brain)
Mechanism of localization: DTPA
Filtration
Mechanism of localization: F18 - FDG
Facilitated diffusion (Carrier mediated transport across membrane via GLUT)
Mechanism of localization: I-123, I-131
Active transport (AtP to move against concentration gradient)
Mechanism of localization: Thallium
Active transport (Na/K Pump)
Mechanism of localization: Rubidium
Active transport (Na/K Pump)
Mechanism of localization: MIBG
Active Transport (Na facilitated norepinephrine uptake system)
Mechanism of localization: DMSA
active transport
Mechanism of localization: Pertechnatate
Secretion (Active transport OUT of gland or tissue)
Mechanism of localization: MAG - 3
secretion (secreted by peritubular capillaries)
Mechanism of localization: Tc-99m IDA
secretion (secreted by hepatocytes)
Mechanism of localization: Sulfur colloid
phagocytosis (RES eats teh colloid particles)
Mechanism of localization: Heat treated RBCs
sequestration
Mechanism of localization: MAA
Capillary blockade (lung perfusion)
Mechanism of localization: MDP
Chemisorption to calcium hydroxyapatite
Mechanism of localization: SM - 153
Chemisorption
Mechanism of localization: Indium WBC
Cellular migration
Mechanism of localization: Octreotide
receptor binding
DAT Scan (I-123 Isoflupane)
receptor binding
Tumors that are PET COLD (6)
1) BAC (adeno in situ) - lung cancer
2) Carcinoid
3) RCC
4) Peritoneal bowel/liver implants
5) anything mucinous
6) prostate
PET HOT - NOT CANCER (6)
1) Infection
2) Inflammation
3) Ovaries in follicular phase
4) Muscles
5) Brown fat
6) Thymus
Indium is better than gallium for evaluating (1)
abdomino-pelvic abscess due to lack of normal bowel excretory pathway
Gallium is better than indium for evaluating (3)
1) Spine
2) diffuse pulmonary process (gallium is probably the agent of choice for the evaluation of pulmonary inflammatory abnormalities)
3) Lymphocytic mediated infection
Tc - HMPAO is better than In WBC (3)
1) children (lower dose)
2) IBD (image early 30-60 minutes)
3) Osteomyelitis in extremity
In WBC is better than Tc - HMPAO (1)
Fever of unknown origin
tumors that take up octreoscan
Somatostatin analog
Taken up by:
1) carcinoid tumor
2) paraganglioma (glomus jugulare tumor, glomus jugulotympanicum, glomus vagale, glomus tympanicum, carotid body tumor)
3) phaeochromocytoma
4) small cell lung cancer
5) pituitary adenoma
6) neuroblastoma
7) medullary thyroid carcinoma
8) pancreatic islet cell tumor
Variable taken up by: meningioma, astrocytoma, breast carcinoma, lymphoma, Merkel cell carcinoma
Excessive aluminum from generator elution on Tc study results in accumulation of radiotracer where?
Causes colloid formation and accumulation in the liver
How frequently is field uniformity checked for nuclear medicine?
Extrinsically (with a collimator) is done daily and checks the collimator and cyrstals
Intrinsically (without a collimator) is done weekly (can use either Na99TcO4 or Co57
If bulls eyes are seen then that is a PMT problem.
Need to compare if defect is seen on intrinsic or extrinsic alone or on both to determine where problem is. If only on extrinsic then the collimator may be cracked!
How frequently are linearity and spatial resolution checked in nuclear medicine?
What about Energy Window?
Center or rotation?
Linearity and SR should be sheck weekely with bar phantom and flood source (Co57)
Energy window should be checked daily (Tc center at 140 keV with 20% window)
Center of Rotation is done with 5 small Tc point sources along the axis of rotation and should be performed monthly.
Radionuclide purity test
1) What are you testing for?
2) How is it performed?
3) What is the NRC allowance?
Testing for Molybdenum in Tc-99m eluate (breakthrough).
Mo (740 keV) is assayed first by shielding lower Tc.
0.15 micro Ci of Mo per 1 milli Ci of Tc, AT THE TIME OF ADMINISTRATION
Ratio less than 0.038 at the time of elution will be suitable for injection at least 12 hours.
Chemical purity test
1) What are you testing for?
2) How is it performed?
3) What is the NRC allowance?
4) What artifact is caused?
Testing for aluminum with pH paper. Must be < 10 mg of Al per 1 mL.
Can show up as liver activity on Tc scan due to clumping (bone study for example)
Can show up in lungs on liver/spleen scan with Sulfur Colloid
Radiochemical purity test
1) What are you testing for?
2) How is it performed?
3) What is seen on the scan?
This is done using thin layer chromatography to essentially check labeling efficiency.
You are testing for free pertechnatate (TcO4)
Due to incomplete reduction by stannous ions or by accidental air injection
Shows up on the scan with gastric, salivary gland and thyroid uptake
Allowable dose exposure limits (NRC) for occupational, public, family of patient and pregnant categories? Lens dose?
Occupational total body dose limit: 50 mSv (5 rem)
Dose to the ocular lens: 150 mSv (15 rem)
Total equivalent organ dose per year: 500 mSv (50 rem)
Embryo/fetus dose over 9 months: 5 mSv (0.5 rem)
Annual dose to the public: 1 mSv (0.1 rem or 100 mrem)
No greater than 2 mrem/hr in an “unrestricted area”
Hot sink limit
1 Ci per year
Package labels and limits
White I: < 0.5 mrem/hr (surface); N/a @ 1 m
Yellow II: < 50 mrem/hr (surface) AND < 1 mrem/hr @ 1 m
Yellow III: 50 < x < 200 mrem/hr (surface) OR 1 < x < 10 mrem/hr @ 1 m
When does a Mo/Tc generator have the max Tc-99m amount? How frequently should generator undergo elution?
Max build up of Tc-99m occurs after about 4 half lives or 23 hrs
Should be eluted daily to prevent accumulation of Tc-99 (notice the not metastable form)
What can cause diffuse muscle uptake on MIBG?
Medications (TCA, antihypertensives, sympathomimetics, cocaine)
How frequently should PET QA “Blank Scan” be done?
What about a normalization scan?
This should be done daily. Can be done with a positron source and no patient in the scanner either Ge 68 or Cs 137 or a uniform source phantom.
Normalization scan should be done monthly or annually? Expose to uniform source, looking for variations in detector elements (variations in crystal thickness, etc?)
Note Ge(68)/Ga(68) system is similar to Mo/Tc, Ga 68 (not 67) is a positron emitter with half life of only 68 minutes.
Name beta minus decay radiotracers
Tc - 99m Xe - 133 I - 131 Strontium - 89 Samarium 153 Y - 90
Name electron capture radiotracers
I - 123 (goes to Te-123m) Thallium -201 (goes to Hg) Indium - 111 (goes to Cadmium) Gallium - 67 (goes to Zn) Cobalt 57 - (goes to Fe)
*** GIIT and Cobalt
Name the beta plus (positron) radiotracers
F-18 (Yields oxygen 18)
Rubidium - 82
N - 13
Low, medium and high energy radiotracers
Low: Tc, I-123, X-133, TI-201 (1-200 keV)
Med: Ga-67 and In-111 (200 - 400 keV)
High: I - 131 (>400 keV)
Qc for Ionizing Chamber or Dose Calibrator
Consistency w/i 5% checked daily
Linearity (quarterly)
Accuracy (annually)
Geometry (installation and anytime it is moved)
10 CFR part 19
10 CFR part 20
10 CFR part 35
19: Notices, instructions and reports to workers
20: Standards for protection against radiation
35: Medical use of by-product material
Major spill thresholds
100 mCi Tc-99m and TI-201
10 mCi In-111, I-123, Ga-67
1 mCi I-131
Recordable event versus Reportable event
Recordable: less than 5 rem whole body dose or single organ dose < 50 rem with error (wrong drug, route, patient or dose >20%) *** Must be kept for 5 years (most other things for only 3 years)
Reportable: mistake causing harm to patient with whole body dose greter than 5 rem or single organ dose > 50 rem
Reporting
- Call NRC w/i 24 hours
- write NRC letter w/i 15 days
- Notify referring doc w/i 24 hours
- Notify patient
Tolerated wipe dose or survey on packages
> 6600 dpm/300 cm^2 is not allowed
Must check within 3 hours of receipt