What is the primary purpose of a collimator in medical dosimetry?

The primary purpose of a collimator in medical dosimetry is to define the radiation beam by restricting its size and shape. Collimators play a crucial role in shaping the treatment beam so that it conforms to the area of interest while minimizing exposure to surrounding healthy tissues. By adjusting the collimator, medical dosimetrists can create a beam that matches the target volume precisely, which is essential for effective treatment delivery and for maximizing the therapeutic ratio – delivering the necessary dose to the tumor while sparing normal tissues.

This beam definition capability is vital in radiation therapy, where precision is paramount. It ensures that the prescribed dose is accurately delivered to the treatment site while adhering to safe dosage limits for adjacent healthy structures. Hence, the collimator is an indispensable tool in ensuring both efficacy and safety in radiation therapy planning and administration.