Electron beam detection in radiotherapy using a capacitor dosimeter equipped with a silicon photodiode

In this study, a newly developed capacitor dosimeter was evaluated using electron beams commonly utilized in radiotherapy. The capacitor dosimeter comprised a silicon photodiode, 0.47- μF capacitor, and dedicated terminal (dock). Before electron beam irradiation, the dosimeter was charged using the dock. The doses were measured without using a cable by reducing the charging voltages using the currents from the photodiode during irradiation. A commercially available parallel-plane -type ionization chamber and solid–water phantom were used for dose calibration with an electron energy of 6 MeV. In addition, the depth doses were measured using a solid–water phantom at electron energies of 6, 9, and 12 MeV. The doses were proportional to the discharging voltages, and the ma ximum dose difference in the calibrated doses measured using a two-point calibration was approximately 5% in the range of 0.25–1.98 Gy. The depth dependencies at energies of 6, 9, and 12 MeV corresponded to those measured using the ionization chamber.Graphical Abstract
Source: Medical and Biological Engineering and Computing - Category: Biomedical Engineering Source Type: research