• Gamma and neutron waves, like those emitted in the explosion of Little Boy over Hiroshima, are types of ‘ionizing radiation’. This means that they have enough energy to knock electrons from atoms to create ions.
• DNA contains four bases – cytosine, guanine, thymine & adenine. The ionized particles can create breaks in the structure of DNA. Cells can repair some of these breaks. Breaks can occur across one or both strands. Cells find it very tough to fix breaks across double strands.
• It is also possible for radiation to change the genetic code directly. Gamma and neutron radiation can alter one of DNA’s bases into another or can even make two bases stick together.
• The mistakes made by the broken DNA may lead to mutations. Sometimes these mutations can be so dangerous that a cell no longer understands its instructions. Rather than repairing itself or self-destructing, it may multiply, which can lead to a tumour.
If you get exposed to low level radiation, your body will just deal with it. If you suffer radiation sickness but later recover, you may have a higher risk of later cancer and miscarriage—higher than the already slight risk. You might also face long-term effects due to tissues that do not normally regenerate. But if you get exposed to a very high dose of radiation, then you’re likely to die because too many cells have been killed for your natural defenses to cope.
