放射性是不稳定原子核因辐射失去能量的过程。它以Becquerels（BQ）进行测量。
1 rem = 0.01 α
1 α = 100 rem
例子:
将15 REM转换为α颗粒：
15 rem = 0.15 α
| REM | α颗粒 |
|---|---|
| 0.01 rem | 0 α |
| 0.1 rem | 0.001 α |
| 1 rem | 0.01 α |
| 2 rem | 0.02 α |
| 3 rem | 0.03 α |
| 5 rem | 0.05 α |
| 10 rem | 0.1 α |
| 20 rem | 0.2 α |
| 30 rem | 0.3 α |
| 40 rem | 0.4 α |
| 50 rem | 0.5 α |
| 60 rem | 0.6 α |
| 70 rem | 0.7 α |
| 80 rem | 0.8 α |
| 90 rem | 0.9 α |
| 100 rem | 1 α |
| 250 rem | 2.5 α |
| 500 rem | 5 α |
| 750 rem | 7.5 α |
| 1000 rem | 10 α |
| 10000 rem | 100 α |
| 100000 rem | 1,000 α |
规则