# Radiotherapy Tools vs Decay Lab

The clearest difference is price: Decay Lab at Free against Radiotherapy Tools's $17.99. Decay Lab also leads on in-app purchases (none vs 1) and update cadence (every 4 days vs every 2 weeks). On ads, device support and iOS requirement there is nothing between them.

Decay Lab is free to download; Radiotherapy Tools costs $17.99 up front. Radiotherapy Tools sells 1 in-app purchase, starting at $29.99 per year. Decay Lab asks for nothing beyond the download.

Radiotherapy Tools ships an update every 2 weeks, Decay Lab every 4 days. The most recent releases landed on October 25, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | Radiotherapy Tools | Decay Lab |
| --- | --- | --- |
| Price | $17.99 | **Free** |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/decay-lab/id6746874842/reviews)** |
| Number of ratings | — | **1** |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 2 weeks | **Every 4 days** |
| Monetization | — | Free |
| Size | 29 MB | 6 MB |
| Requires iOS | 17 | 17.0 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 12+ | 4+ |
| Developer | [Yavuz Erol](https://appshunter.io/developer/1797117198) | [Carlos Uribe](https://appshunter.io/developer/1818871232) |

## What reviewers say

### Radiotherapy Tools

[App page](https://appshunter.io/ios/app/radiotherapy-tools/id6742157886)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium Plan | $29.99 | per year |


### Decay Lab

[App page](https://appshunter.io/ios/app/decay-lab/id6746874842)

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.

**Highlights:** Radioactive decay calculations, Activity at different times, Decay corrections, Bq/Ci unit conversions, Absorbed/equivalent dose conversions, Dose rate conversions, Built-in nuclide data

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Radiotherapy Tools free?

Radiotherapy Tools costs $17.99, and also offers in-app purchases.

### Is Decay Lab free?

Decay Lab is free to download, with no in-app purchases.

### Do Radiotherapy Tools or Decay Lab have ads?

Neither Radiotherapy Tools nor Decay Lab shows ads.

### Which is updated more often, Radiotherapy Tools or Decay Lab?

Radiotherapy Tools ships an update every 2 weeks, and Decay Lab every 4 days. Most recently, Radiotherapy Tools was updated on October 25, 2026 and Decay Lab on October 28, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*