Patient Release After a Radiopharmaceutical (10 CFR 35.75, NRC Regulatory Guide 8.39)
Patient release after a radiopharmaceutical, by NRC Regulatory Guide 8.39.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Radionuclide
- I-131
- Administered activity
- 55
- Activity unit
- mCi
- I-131 patient-specific: condition treated
- Hyperthyroidism
- I-131 patient-specific: occupancy factor, first 8 hours
- 0.75
- I-131 patient-specific: occupancy factor after 8 hours
- 0.25
Result: release may be authorized; instructions, including written ones, are required
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Radionuclide
- Administered activity
- Activity unit
- Measured dose rate at 1 meter
- Another radionuclide: exposure rate constant
- Another radionuclide: physical half-life
- I-131 patient-specific: condition treated
- I-131 patient-specific: occupancy factor, first 8 hours
- I-131 patient-specific: occupancy factor after 8 hours
How this is calculated
Citation
NRC Regulatory Guide 8.39, Revision 1 (April 2020): Tables 1 and 2, Equations 2, 3 and B-5, Tables A-1 and B-1. 10 CFR 35.75: release at 5 mSv (0.5 rem), instructions above 1 mSv (0.1 rem), record of the basis for release. Read the sources: Regulatory Guide 8.39 Rev. 1 ↗, 10 CFR 35.75 ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.