Design of programmable gain amplifier for dosimetry of variable energies in radiotherapy

Radiotherapy largely relies on the accuracy in radiation dose measurement. Before going for a dose delivery to the patient, proper calibration of radiation dose has to be conducted. The linac produces variable energies and to maintain the dose accuracy to 3 percent can be a difficult task. The control system used for the dose measurement provides the concept of programmable gain amplifier for the setting of various gain values with respect to variable radiation energies. The proposed design of programmable gain amplifier provides continuous as well as discrete gain values through the control of Field Programmable Gate Array (FPGA) with an automatic selection of radiation energies.