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 β = 100 rem
1 rem = 0.01 β
例子:
将15 beta颗粒转换为REM：
15 β = 1,500 rem
| beta颗粒 | REM |
|---|---|
| 0.01 β | 1 rem |
| 0.1 β | 10 rem |
| 1 β | 100 rem |
| 2 β | 200 rem |
| 3 β | 300 rem |
| 5 β | 500 rem |
| 10 β | 1,000 rem |
| 20 β | 2,000 rem |
| 30 β | 3,000 rem |
| 40 β | 4,000 rem |
| 50 β | 5,000 rem |
| 60 β | 6,000 rem |
| 70 β | 7,000 rem |
| 80 β | 8,000 rem |
| 90 β | 9,000 rem |
| 100 β | 10,000 rem |
| 250 β | 25,000 rem |
| 500 β | 50,000 rem |
| 750 β | 75,000 rem |
| 1000 β | 100,000 rem |
| 10000 β | 1,000,000 rem |
| 100000 β | 10,000,000 rem |
规则