Radioactive Decay, Precalibration and Activity Units (Label Half-Lives)
Radioactive decay: the activity at another time, or the time to reach an activity.
Open the tool → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Radionuclide
- Tc-99m (6.02 hours)
- Activity at calibration
- 30
- Activity unit
- mCi
- Calibration date and time
- 2026-10-12T08:00
- Target date and time
- 2026-10-12T14:01
Result: 15.01 mCi of Tc-99m on October 12, 2026 at 2:01 pm: 15.01 mCi (555.2 MBq).
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Radionuclide
- Half-life, for another radionuclide
- Half-life unit
- Activity at calibration
- Activity unit
- Calibration date and time (YYYY-MM-DDTHH:MM)
- Target date and time (YYYY-MM-DDTHH:MM)
- Or a target activity, to get the time it is reached
How this is calculated
Citation
Physical half-lives from the FDA labels of Technelite, Fludeoxyglucose F 18, Hicon, AdreView, Octreoscan, thallous chloride Tl 201, Lutathera, Xofigo, Cardiogen-82, Netspot and Ammonia N 13 (DailyMed). Decay-in-storage: 10 CFR 35.92. Read the sources: Technelite label ↗, Fludeoxyglucose F 18 injection label ↗, Hicon label ↗, AdreView label ↗, Octreoscan label ↗, Thallous chloride Tl 201 injection label ↗, Lutathera label ↗, Xofigo label ↗, Cardiogen-82 label ↗, Netspot label ↗, Ammonia N 13 injection label ↗, 10 CFR 35.92 ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.