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Home > Issues > RetrieveEnergy Spectrum of Electromagnetic Radiation for a Dual-Energy Cone-Beam Computed Tomography in Radiotherapy
Journal of Magnetics, Volume 25, Number 4, 31 Dec 2020, Pages 614-619
Seunghyeop Baek (Department of Radiological Science, Yonsei University), Jin Sung Kim (Department of Radiation Oncology, Yonsei University College of Medicine,), Woo Sang Ahn * 
(Department of Radiation Oncology, Gangneung Asan Hospital, University of Ulsan College of Medicin), Sohyun Ahn * (Department of Radiation Oncology, Yonsei University College of Medicine)
(Department of Radiation Oncology, Gangneung Asan Hospital, University of Ulsan College of Medicin), Sohyun Ahn * (Department of Radiation Oncology, Yonsei University College of Medicine)
Abstract
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 192Ir
source. The energy spectrum was measured using a cadmium zinc telluride (CZT) detector. A figure-of-merit
(FOM) value was defined and evaluated in order to consider both the increase in the mean energy and the
decrease in the intensity according to the filter. For a 1 mm thick filter, the FOM values were 0.82 and 0.92 for
tube voltages of 100 and 120 kVp, respectively. The intens ity was maintained reasonably and the effect of
increasing the mean energy was evident, thus indicating its suitability for implementing dual-energy CBCT.
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 192Ir
source. The energy spectrum was measured using a cadmium zinc telluride (CZT) detector. A figure-of-merit
(FOM) value was defined and evaluated in order to consider both the increase in the mean energy and the
decrease in the intensity according to the filter. For a 1 mm thick filter, the FOM values were 0.82 and 0.92 for
tube voltages of 100 and 120 kVp, respectively. The intens ity was maintained reasonably and the effect of
increasing the mean energy was evident, thus indicating its suitability for implementing dual-energy CBCT.
Keywords: electromagnetic spectrum; CZT detector; dual-energy CBCT; energy modulation filter; energy in electromagnetic radiation
DOI: https://doi.org/10.4283/JMAG.2020.25.4.614
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