What is the function of bolus in radiation therapy?

The function of bolus in radiation therapy is to create a tissue-equivalent material for radiation beams. When bolus is used, it is typically placed on the surface of the skin where the radiation beam is directed. Its primary role is to simulate the effects of tissue so that the radiation dose can be more accurately delivered to the target area while also ensuring that the skin surface and the underlying tissue are adequately treated. This is particularly important in cases where the tumor is located close to the skin or on the surface, as the bolus helps to ensure that the radiation dose is distributed as intended.

One of the key benefits of using bolus is that it can help to bring the high dose of radiation closer to the skin's surface, compensating for any irregularities in patient anatomy and allowing for a more uniform dose distribution. This is crucial in achieving the desired therapeutic effect while minimizing damage to surrounding healthy tissues.