Application of the BPW-34 photodiode for depth dose measurements in the presence of inhomogeneities

In recent years, semiconductor detectors have found application in radiation dosimetry due to their high sensitivity and small dimensions. In previous papers the response of the common photodiode BPW-34 has been studied to evaluate its stability for use as a radiation dosemeter. In this study, the BPW-34 was used for measuring percentage depth dose in inhomogeneous tissues. Measurements were performed along the central axis of both 60Co γ ray and 6 MV X ray field in a Perspex phantom containing low density inhomogeneities. The percentage depth doses measured with the photodiode were compared with those obtained with TLDs irradiated in the same conditions. The results show that the discrepancy between the responses of the photodiode and that of TLDs is less than 1%, indicating that the BPW-34 can be used for measuring dose distributions in heterogeneous tissues. (author)