Patient Dose Verification with In Vivo Dosimetry Using Diodes in Radiotherapy

Abstract

This study aims to use semiconductor diodes for real-time verification of the prescribed dose to the patient in radiotherapy and the dose delivered during treatment. A quality assurance step in radiotherapy is provided by comparing the dose prescribed in patient treatment planning with the doses delivered during treatment. A well-planned in vivo dosimetry program in the clinic prevents the development of undesirable situations in patient treatments. For this purpose, patient dose verification was performed using the Scanditronix Wellhofer in vivo dosimetry system in a total of 61 patients in lung, breast, pelvic box, brain, prostate, craniospinal, esophagus, and nasopharynx patient groups. Patient entrance doses were measured with semiconductor diodes placed on the patient. Corrected doses were calculated by using measured doses with correction factors appropriate to the treatment conditions and compared with the planned doses from patient planning. According to the results of the study, it was found that there was a difference of approximately 5% between the measured doses and the corrected doses in patient treatment, and this difference decreased to less than 1% between the corrected doses and the planned doses. These results emphasize that correction factors should be determined correctly and used correctly in patient dose verification in the clinic.