| Isotope | Half Life | 
| Polonium-215 | 0.0018 seconds | 
| Uranium-238 | 4.5 billion years | 
| Radium-226 | 1600 years | 
| Cobalt-60 | 5.26 years | 
| Iodine-131 | 8.07 days | 
| Sodium-24 | 15 hours | 
| Bismuth-212 | 60.5 seconds | 
| Holmium-166 | 1200 years | 
| Selenium-79 | 1130000 years | 
| Samarium-147 | 106000000000 years | 
| Indium-115 | 
 | 
| Carbon-14 | 5730 years | 
| Uranium-233 | 159200 years | 
| Rhenium-186m | 200000 years | 
| Technetium-99 | 211000 years | 
| Krypton-81 | 229000 years | 
| Uranium-234 | 245500 years | 
| Chlorine-36 | 301000 years | 
| Curium-248 | 340000 years | 
| Bismuth-208 | 368000 years | 
| Plutonium-242 | 373300 years | 
| Aluminum-26 | 717000 years | 
| Selenium-79 | 1130000 years | 
| Iron-60 | 1500000 years | 
 years
years