What is the main advantage of using custom compensators for missing tissue in MV therapy over bolus?

Using custom compensators for missing tissue in megavoltage (MV) therapy has the primary advantage of preserving skin sparing compared to bolus. This is significant because bolus, which is often used to bring the dose closer to the surface, causes higher doses at the surface layer, potentially increasing skin toxicity and compromising normal tissue preservation.

Custom compensators are designed to mimic the tissue density and geometry, allowing for better dose distribution while maintaining the desired tumor coverage. By carefully tailoring the compensator, clinicians can achieve appropriate dose distribution to the target volume without unnecessarily increasing the dose at the skin surface. This helps to protect the surrounding healthy tissues from excessive radiation, promoting better patient outcomes and reducing the risk of adverse effects such as skin burns or other complications associated with higher surface doses.