How does alpha radiation affect body tissue?

Alpha radiation is composed of alpha particles, which are relatively heavy and carry a positive charge. When alpha particles interact with body tissues, they have a very short range due to their mass and charge. However, within that short distance — typically just a few centimeters in air and much less in biological tissue — alpha particles deposit a significant amount of energy. This results in a high level of ionization, which can cause substantial damage to the cells they interact with.

The high ionization density over that limited range is what makes alpha radiation potentially harmful, especially if alpha-emitting substances are ingested or inhaled, allowing them to come into close contact with sensitive tissues. In contrast, other forms of radiation, like beta or gamma radiation, have different properties in terms of penetration and ionization density, allowing them to affect tissues differently.

In summary, the correct answer accurately reflects that alpha radiation produces a lot of ionization over a short distance. This property is what makes it particularly damaging to tissues when close to or inside the body, explaining the need for caution with alpha-emitting isotopes.