Estimation of organ doses and effective doses in image-guided respiration-gated radiotherapy
Minoru Nakao1, Satoshi Obara2, Kuniaki Nabatame3
1National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan Kanazawa University, 5-11-80, Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan mnrnakao@nirs.go.jp.
Abstract:
Dose conformity in thoracic and abdominal ion-beam radiotherapy is degraded by respiratory motion. To improve conformity, an image-guided respiration-gated system can be used in the treatment room. The purpose of this study was to estimate the organ doses and effective doses to patients from an image-guided respiration-gated system. Glass dosemeters were inserted into an adult anthropomorphic phantom and were attached to the surface on the phantom. The phantom was placed on the treatment couch, and the imaging dose from fluoroscopy was evaluated. In addition to the organ doses, the effective doses were also estimated according to the ICRP Publication 103. The irradiation time is over 3-5 min per beam angle. When image acquisition conditions were assumed for thoracic treatment, the effective doses and maximal skin doses were 0.48-0.79 mSv and 5.9-9.9 mGy, respectively. The estimated doses can be the base data for considering radiological protection in the radiotherapy.
