PAAT vs Decay Lab
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
PAAT
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PAAT was developed to enhance the capabilities of States in assessing radiation alarms triggered by a person. In most cases, the reason the person will set off an alarm is a medical treatment or diagnostic procedure involving the administration of a radiopharmaceutical. When a radiation alarm is triggered by a person, PAAT can be used by the investigating officer to conduct a simple interview and measurement. The information in the App provides assistance for the investigating officers in States in the assessment of radiation alarms caused by persons to more effectively and efficiently combat the movement of nuclear and other radioactive materials out of regulatory control at points of entry and major public events (MPE). Note: • The App does not collect any identifying personal data. • The dose estimates in the App are for standard models and should not be considered patient-specific under any circumstances. • The assessment results shall be used only for nuclear security purposes. • The App has not been extensively tested on all platforms, under all conditions. As such, users of this tool must verify all results prior to decision making.
Decay Lab
This tool simplifies radionuclide decay calculations and radiation unit conversions. It's designed for professionals and students in nuclear medicine and related fields, offering a focused, offline workflow for quick and consistent results.
- Radioactive decay calculations
- Activity at different times
- Decay corrections
- Bq/Ci unit conversions
- Absorbed/equivalent dose conversions
- Dose rate conversions
- Built-in nuclide data
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DecayLab makes radionuclide decay calculations and radiation unit conversions quick and straightforward. Designed for nuclear medicine professionals, researchers, educators, and students, it provides a clean, focused workflow that works entirely offline. Key features: • Calculate radioactive decay for a wide range of radionuclides • View activity at different reference and calculation times • Apply decay corrections quickly and consistently • Work with Bq, kBq, MBq, GBq and TBq, alongside nCi, µCi, mCi and Ci • Convert absorbed dose in Gy and rad, and equivalent dose in Sv and rem • Convert dose rates per second, minute, hour or day • See one value in every other unit at once, rather than one pair at a time • Access built-in radionuclide half-life data for 1,625 nuclides • Use all calculation features without an internet connection Gray and sievert are kept in separate tables. Converting between them requires a radiation weighting factor, which is a judgement about radiation type rather than a unit conversion, so DecayLab does not offer it. DecayLab is useful for: • Nuclear medicine technologists • Medical physicists • Radiation safety professionals • Researchers and educators • Students in nuclear medicine and related fields Whether you're checking an activity value, preparing calculations for a workflow, or studying radioactive decay, DecayLab keeps the process clear and efficient. Important: DecayLab is a calculation and educational tool. Results should be independently verified before being used in clinical, diagnostic, therapeutic, or safety-critical decisions.
Screenshots
Verdict
The clearest difference is update cadence: Decay Lab at every 4 days against PAAT's every 3 weeks. PAAT's advantage is iOS requirement (13.0 vs 17.0). On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
PAAT ships an update every 3 weeks, Decay Lab every 4 days. The most recent releases landed on November 3, 2026 and November 5, 2026 respectively.
| Parameter | PAAT | Decay Lab |
|---|---|---|
| Price | Free | Free |
| Rating | — | 5.0 (1 ratings) — better |
| Number of ratings | — | 1 — better |
| Update frequency | Every 3 weeks | Every 4 days — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | — | Free |
| Devices | iPhone, iPod | iPhone, iPad |
| Requires iOS | 13.0 — better | 17.0 |
| Further details — not scored | ||
| Size | 11 MB | 6 MB |
| Age rating | 4+ | 4+ |
| Developer | IAEA | Carlos Uribe |
In-app purchases
PAAT
No in-app purchases
Decay Lab
No in-app purchases









