SPECIAL - Nuclear Safety Flashcards
Radiochemical purity
free pertechnetate; tested with thin layer chromatography
Chemical purity
alumina breakthrough; tested with color indicator paper
Radionuclide purity
Mo breakthrough; tested with dose calibrator with lead shield
Limit for radiochemical purity
95% for Tc-99m pertechnetate, 92% for Tc-99m sulfur colloid, 90% for all other Tc-99m
Isotopes produced from a generator
Tc-99m, rubidium; generators are used to produce short-lived isotopes
Limit for radionuclide purity
0.15 uCi of Mo per mCi of Tc-99m
Limit for chemical purity
10 ug of aluminum per mg of eluate
Shielding for a beta-minus emitter
plastic (low Z); lead (high Z) would result in Bremsstrahlung
How long do you have to keep radioactive material?
10 half lives; includes waste and contaminated materal (e.g. clothing, shoes)
Ring badge positioning
dominant hand, index or ring finger, label towards source (palm usually), under a glove (avoid contamination)
CFR 19
WORKERS; notices, instructions, and reports to worker
CFR 20
PROTECTION; standards for protection against radiation
CFR 35
MEDICAL USE; medical use of by-product material
Major spill threshold of 100 mCi
Tc-99m, Tl-201
Major spill threshold of 10 mCi
In-111, Ga-67, I-123
Major spill threshold of 1 mCi
I-131
Major spill procedure
clear area/alert => absorbent paper (stop spread) => shield if possible => lock door => report to RSO => decomination; DO NOT CLEAN
Minor spill procedure
notify people in area => absorbent paper => CLEAN up => survey with G-M => report to RSO
Criteria for disposing radioactive material
physical half-life <120 days, greater than 10 half-lives passed, activity indistinguishable from background at time of disposal, all labels removed, keep records for 3 years
Checklist for receiving goods
check within 3 hours on same day or start of next business day if received after hours; visually inspect package, check at surface and at 1 meter with survey meter, wipe test at surface, keep records for 3 years
Received goods with activity >200 mrem/hr at surface or >10 mrem/hr at 1 meter
notify RSO, NRC, and delivery company
What does TI stand for?
Transportation Index
What does TI measure?
dose rate at the time of shipping (written on label by manufacturer); TI is AT 1 METER
How is TI measured?
G-M counter used to measure mrem/hr at 1 meter
How often should a Geiger-Muller counter be calibrated?
annually
How long to keep records for a reportable event?
3 years
What is the frequency of an ambient radiation survey?
daily (at end of the work day) where written directives are prepared or administered
Potential dose to others at which written instructions must be given to I-131 patients to minimize exposure
> 1 mSv
Are outpatients actually measured before they leave our department?
only if the expected (calculated) exposure is >5 mSv to any individual
Is there a dose limit to the caregiver of an individual who received I-131?
no regulated dose limit for caregiver, only that which does not cause health problems
Resume breastfeeding after Tc-99m in…
12-24 hours
Resume breastfeeding after I-123 in…
2-3 days
Resume breastfeeding after I-131 in…
never (do NOT resume)
Resume breastfeeding after FDG PET in…
no cessation required
Resume breastfeeding after Tl-201, Ga-67, or In-111 in…
1-4 weeks
Radiation limits for white I package label
<0.5 mrem/hr at surface; no TI; no special handling required
Radiaiton limits for yellow II package label
<50 mrem/hr at surface AND <1 mrem/hr at 1 meter; special handling required
Radiation limits for yellow III package label
<200 mrem/hr at surface OR <10 mrem/hr at 1 meter; special handling required
Dose limit for an uncontrolled/unrestricted area?
<0.02 mSv/hr AND <1 mSv over 7 consecutive days
Dose threshold for a controlled/restricted area?
> 0.02 mSv/hr; area under supervision of a person in charge of radiation protection
What radiation level defines a “radiation area”?
Possible excess of 5 mrem/hr at 30 cm
What radiation level defines a “high radiation area”?
Possible excess of 100 mrem/hr at 30 cm
What radiation level defines a “very high radiation area”?
Possible excess of 5 Gy/hr at 30 cm; access needs to be restricted (e.g. lock on door)
Medical events must be reported to NRC verbally within…
1 day of discovery
Medical events must be reported to referring physican verbally within…
1 day of discovery
Medical events must be reported to NRC in written form within…
15 days of discovery
Personal dosimeter requirement?
individuals who are likely to receive >10% of allowable occupational exposure limits
Maintenance of records?
Actions taken by management relative to the radiation protection program must be kept for 5 years. All other records need to be kept for 3 years.
Diagnostic recordable event
wrong patient OR wrong radionuclide OR wrong dose (>20%) OR wrong route OR wrong site, AND whole body dose <50 mSv AND single organ dose <500 mSv
Diagnostic reportable event (a.k.a. medical event)
wrong patient OR wrong radionuclide OR wrong dose (>20%) OR wrong route OR wrong site, AND whole body dose >50 mSv OR single organ dose >500 mSv; OR any administration that results in unintended permanent functional damage
Therapeutic recordable event
dose administered differed from prescribed dose by >10%
Therapeutic reportable event
dose administered differed from prescribed dose by >20%
Pregnancy after I-131 treatment?
wait 6-12 months
When is sterility/pyrogenicity of radiopharmaceuticals tested?
post-administration
Criteria to release patient after I-131 treatment
dose received is <33 mCi, dose rate at 1 meter is <7 mrem/hr, potential dose to a maximally exposed person is <5 mSv; if patient does not meet at least 1 criteria, must admit to hospital
Regulations for disposal of radioactive human waste
human excreta is not regulated
Written directive from an authorized user is required for what dose of I-131?
30 uCi or higher
How often must sealed sources have leak tests?
every 6 months
Surface contamination limit for a radioactive material use area?
6600 dpm/300 cm^2 (measured with wipe test); limit is 10% for a non-RAM use area
Precautions for Xe-133 use
low vent, charcoal trap; negative pressure room no longer required by NRC
Exceed annual occupational limit by 5x
1 hour reporting to NRC