La radiactividad es el proceso por el cual un núcleo atómico inestable pierde energía por radiación.Se mide en Becquerels (BQ).
1 t½ = 1,000 mSv 
1 mSv = 0.001 t½ 
Ejemplo: 
Convertir 15 Vida media a Milisabuela:
15 t½ = 15,000 mSv 
| Vida media | Milisabuela | 
|---|---|
| 0.01 t½ | 10 mSv | 
| 0.1 t½ | 100 mSv | 
| 1 t½ | 1,000 mSv | 
| 2 t½ | 2,000 mSv | 
| 3 t½ | 3,000 mSv | 
| 5 t½ | 5,000 mSv | 
| 10 t½ | 10,000 mSv | 
| 20 t½ | 20,000 mSv | 
| 30 t½ | 30,000 mSv | 
| 40 t½ | 40,000 mSv | 
| 50 t½ | 50,000 mSv | 
| 60 t½ | 60,000 mSv | 
| 70 t½ | 70,000 mSv | 
| 80 t½ | 80,000 mSv | 
| 90 t½ | 90,000 mSv | 
| 100 t½ | 100,000 mSv | 
| 250 t½ | 250,000 mSv | 
| 500 t½ | 500,000 mSv | 
| 750 t½ | 750,000 mSv | 
| 1000 t½ | 1,000,000 mSv | 
| 10000 t½ | 10,000,000 mSv | 
| 100000 t½ | 100,000,000 mSv |