The dose to a patient’s skin and build-up region increases with which factor?

The dose to a patient’s skin and build-up region increases with the placement of bolus material. When bolus is used, it effectively raises the surface dose by replacing air with tissue-equivalent material. This is because bolus material, often made of plastic or a similar substance, helps to bring the region of maximum dose closer to the skin surface, ensuring that more radiation is deposited in the build-up region, which is particularly important for treating superficial tumors.

In the context of treatment planning, using bolus can also help tailor the dose distribution to ensure that the intended area receives adequate treatment while minimizing exposure to surrounding healthy tissues. The bolus material creates a situation where the radiation treatment is optimized for specific clinical objectives, enhancing the effectiveness of radiation therapy for skin lesions or other superficial targets.