What must patient immobilization devices not do during treatment?

Patient immobilization devices play a crucial role in ensuring the effectiveness and safety of radiation therapy. Their primary function is to restrict movement so that the tumor area remains in the same position during each treatment session. However, these devices must not interfere with the treatment beam. Interference could lead to misalignment of the radiation dose delivered to the target area, potentially resulting in inadequate treatment of the tumor or increased exposure of surrounding healthy tissues to radiation.

While enhancing patient comfort, restricting movement, and providing warmth can be beneficial aspects of immobilization devices, they are secondary to their primary purpose of not obstructing or altering the path of the treatment beam. Any obstruction that interferes with the radiation could compromise the treatment's effectiveness and patient safety. Therefore, ensuring that immobilization devices do not interfere with the treatment beam is a fundamental requirement in the design and use of these devices in clinical practice.