Evaluation of Absorbed Dose for CBCT in Image-guided Radiation Therapy: Comparison of Each Devices and Facilities
| Autor: | Yumiko Kitazato, Fujio Araki, Toshihisa Kawasaki, Masahiro Enzaki, Yoshinobu Shimohigashi, Shinji Kawamura, Masahiko Toyoda, Katsutoshi Shirieda, Daisuke Kawahara, Yuji Nakaguchi, Noriyuki Kuga |
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| Rok vydání: | 2017 |
| Předmět: |
Dosimeter
Phantoms Imaging business.industry Radiotherapy Planning Computer-Assisted medicine.medical_treatment Radiotherapy Dosage General Medicine Dose distribution Cone-Beam Computed Tomography Imaging phantom 030218 nuclear medicine & medical imaging Radiation therapy 03 medical and health sciences 0302 clinical medicine 030220 oncology & carcinogenesis Absorbed dose Calibration Ionization chamber Dose verification Medicine business Nuclear medicine Radiotherapy Image-Guided Image-guided radiation therapy |
| Zdroj: | Japanese Journal of Radiological Technology. 73:309-316 |
| ISSN: | 1881-4883 0369-4305 |
| DOI: | 10.6009/jjrt.2017_jsrt_73.4.309 |
| Popis: | Recently, intensity-modulated radiation therapy (IMRT) is used worldwide, highly accurate verification of the location using image-guided radiation therapy (IGRT) has become critical. However, the use of cone-beam computed tomography (CBCT) to ascertain the location each time raises concerns about its influence on radiotherapy dosage and increased radiation exposure. The purpose of this study was to measure the absorbed dose using nine kilovoltage (kV) devices and two megavoltage (MV) devices (total 11 devices) at eight facilities, compare the absorbed dose among the devices, and assess the characteristics of the respective devices to ensure optimal clinical operation. For the measurement of the absorbed dose, a farmer-type ionization chamber dosimeter, calibrated using a 60Co and an IMRT dose verification phantom manufactured from water-equivalent material RW3, was used to measure the absorbed dose at nine points in the phantom for two regions, the pelvic and cephalic region. The average absorbed dose of the pelvic region was 3.09±0.21 cGy in kV-CBCT (OBI), 1.16±0.16 cGy in kV-CBCT (XVI), 5.64±1.48 cGy in MV-CBCT (4 MV), and 6.33±1.54 cGy in MV-CBCT (6 MV). The average absorbed dose of the cephalic region was 0.38±0.03 cGy in kV-CBCT (OBI), 0.23±0.06 cGy in kV-CBCT (XVI), 4.02±0.72 cGy in MV-CBCT (4 MV), and 4.46±0.77 cGy in MV-CBCT (6 MV). There was a difference in the absorbed dose at the measured points as well as in the dose distribution in the phantom cross section. No major difference was observed in the absorbed dose among identical devices, but a difference was identified among the devices installed at multiple facilities. Therefore, the angle of rotation should be paid attention to when CBCT is taken, and the image-taking conditions should be determined. In addition, it is important to handle the devices only after ascertaining the absorbed dose of each device. |
| Databáze: | OpenAIRE |
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