What factors affect the patient dose in radiation therapy?

The correct answer reflects the critical factors that are directly related to the application and delivery of radiation during therapy. Specifically, the source-to-image distance (SID), time of exposure, kilovoltage peak (KVP), and collimation are all pivotal in determining the patient dose.

The SID affects the intensity of radiation reaching the patient—greater distances reduce exposure due to the inverse square law. Time of exposure is directly related to the dose; longer exposure times result in higher doses. KVP influences the penetrating ability of the beam and, consequently, the dose received by the patient. Collimation, which narrows the beam, helps minimize unnecessary exposure to surrounding tissues, thereby affecting the overall dose received by the targeted area.

These parameters are instrumental in ensuring that radiation therapy is delivered effectively while minimizing harmful exposure to surrounding healthy tissues, making them key considerations in radiation dose management.