Energy Spectrum of Electromagnetic Radiation for a Dual-Energy Cone-Beam Computed Tomography in Radiotherapy

To implement dual-energy cone-beam computed tomography (CBCT), a 1 to 3 mm thick copper filter was applied in front of the kilovolt generator mounted on a medical linear accelerator. The energy calibration was performed from three energy peaks among the electromagnetic radiation, gamma rays, emitted by the SUP192/SUPIr source. The energy spectrum was measured using a cadmium zinc telluride (CZT) detector. A figure-of-merit (FOM) value was...