Nucs physics/QC

Question 1

cyclotron produced

Answer 1

Mother Fucking Gargantuine Technique: moly-99, FDG-18, Gallium 67, Thallium-201

Question 2

Nuclear reactor/fission produced

Answer 2

MIXing Target: Moly 98, Iodine 131, Xenon 81, Thallium 201

Question 3

Generator produced

Answer 3

T-99m

Krypton 81m

Question 4

Testing T-99m production

Answer 4

1) Radionuclide purity, ie: How much Mo in Tc, ie: Mo breakthrough.
- tested in dose calibrator w/ lead shield
* 0.15 µCi Mo / 1 milliCi of Tc

high yield trivia:

• ratio must be abd at time of ADM, not elution
• assay Mo before Tc

2) Chemical purity: How much Al in Tc?
- pH paper
* <10 µg Al/ 1mL Tc

ways to show:

• Lung act on liver/spleen scan
• Liver on Tc scan

high yield trivia:
-testing not required by NRC states

3) radiochemical purity: Free Tc, labelling efficacy
- thin layer chromatography
* 95% Na99 TcO4
* 92% Tc99 sulfur colloid (MAA)
* 91% all other Tc99

-free T99: salivary, stomach, thyroid

Question 5

half life Mo-99

Answer 5

67 hrs

Question 6

ten half life rule

Answer 6

how long you keep radioactive material

Question 7

low E

Answer 7

<200

T99, I-123, X-133, TI 201

Question 8

medium E

Answer 8

200-400 keV

Indium 111 and Gallium 67

Question 9

High E

Answer 9

> 400 kEv

• I-131
• FDG 18

Question 10

ideal collimator for high and lower E

Answer 10

High: tall, thick, wide holes
Lw: short, thin, narrow holes

Question 11

collimator types

Answer 11

• parallel-sensitivity not affect by distance
• pinhole: magnify and invert
• converge: magnify, no inversion
• diverging: minify

Question 12

Testing QC for gamma cameras

Answer 12

*DONE BY TECH

1) field uniformity-Testing crystal uniformity/homogeneity of system.
- “flood” w/ T99Na point source (intrinsic) or Co57 sheet.
- 4 quadrant bar phantom. Img is a shadow of lead bars on crystal

• extrinsic=w/ collimator. Testing collimator and crystal
• Daily.
• intrinsic-w/o collimator.
• Weekly

Goal:
-5-10 million counts

Bad study:
see tubes

2) window setting- testing symmetric window centered at peak E
- syringe, vial or patient

Time:
-Daily, bf each study

Goal:
-Tc=20% window at 140keV

Bad study:
off peak/fuzzy

3) image linearity & spatial resolution
-lead bar phantom btw collimator and 57Co sheet OR
???????????-FWHM

Time:
-weekly

Goal:
straight lines that you can see separately

bad study:

• wavy lines (linearity)
• can’t differentiate separate bars (spatial res)

4) center of rotation- alignment of SPECT gamma cameras
- 5 small Tc99 point sources along axis of rotation

Time: monthly

Goal: straight axis

Question 13

set up of gamma cam

Answer 13

patient –> collimator –> crystal 0-> PMT –> pulse heigh analyzer

Question 14

mnemonic for gamma cam

Answer 14

Daily: EU W: Every Usual Weekday
Weekly: Linearity/SR & IU: Lazy Sunday Is Usual
Monthly: COR: Can’t Own Rent

Question 15

what do survey meters measure

Answer 15

Geiger-Muller

• exposure rates (mR/h)
• counting rates (counts per min (CPM))

Dose calibrator/ion chamber
-mCi or MBA

well counter

• CPM
• disintegrations/min

Thyroid prone:
-disintegrations/ min

Question 16

scintillation detectors

Answer 16

1) well counters-contamination
- weekly
- daily package wipes

2) organ uptake probes, ex: thyroid
3) hand held-measuring radioactive waste at background after 10 t1/2 decay-in-storage (for radionuclides with < 120-day t1/2)

Question 17

Dose Calibrator Checks

Answer 17

CLAG
*ALL DONE AT INSTALLATION

Constancy/consistency-instrument precision, reproducibility of measurements

• Cs-137 +/- 5%
• DAILY

Linearity-ability of calibrator to measure radioactive at all clinically applicable low to high levels

1) high act Tc99 over 80 hrs
2) high act t99 in lead shields (lower levels)
* QUARTLY

Accuracy: accurately assay samples
-ANNUAL

Geometry: tests eff due to volume of source
-REPAIR, RECALIBRATION, MOVING INSTRUMENT

Question 18

labelling packages

Answer 18

white
Yello II
Yellow III

Question 19

gas containing survey meters

Answer 19

• geiger-muller (low E)

- dose calibrator/ion chamber (hi E)

Question 20

effective dose at which patient may be released home

Answer 20

5mSv

Question 21

transport indext (TI)

Answer 21

highest radiation level at 1 m from surface of package.

Ex: TI = 2 –> at 1 m from package, the radiation intensity that is measured should be no more than 2 mrem/hr (0.02 msV/hr)

• if radiation exposure of received package great than what is listed on placard, one should consider if shielding was damaged or wrong radish was shipped or label is wrong and
• notify proper authorities

Question 22

Transport labels

Answer 22

White I:

• surface radiation level <0.5 mrem/hr
• radiation level at 1 m: not applicable

Yellow II

• surface radiation level: <50 mrem/h AND
• radiation level at 1 m: <1 mrem/hr

Yellow III

• surface radiation level: 50-200 mrem/hr
• radiation level at 1 m: 1-10 mrem/hr