Abstract

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Title:: Dosimetric study of fixed-jaw technique in intensity-modulated radiotherapy for middle thoracic esophageal carcinoma

Author(s):: SONG Wei; LU Hong; MA Jun; ZHAO Di; LIU Jie; YU Dahai; ZHANG Biyun; Department of Radiation Oncology, Jiangsu Province Hospital of Chinese Medicine, Nanjing 210029, China

Keywords:: Keywords: esophageal carcinoma; fixed-jaw technique; intensity-modulated radiotherapy; dosimetry

Abstract:: Abstract: Objective To investigate the potential dosimetric benefits of fixed-jaw intensity-modulated radiotherapy (fj-IMRT) plans over conventional split-field IMRT (sf-IMRT) plans for middle thoracic esophageal carcinoma. Methods Both fj-IMRT and sf-IMRT plans were designed for selected 10 patients receiving radical radiotherapy for middle thoracic esophageal carcinoma. The conformity index and homogeneity index of target areas, the dose-volume parameters of target areas and organs-at-risk, the total number of fields and monitor units were calculated and analyzed using paired t-test. Results Compared with fj-IMRT plans, sf-IMRT plans had a lower target D2% (P=0.025). The mean dose (Dmean), V5, V10 and V20 of the lungs, the Dmean, V5, V10, V20, V30 and V40 of the left lung, the Dmean, V5 and V10 of the right lung, the Dmean and V40 of the heart, and the Dmean, V5, V10 and V20 of the body volume minus PTV (body-PTV) in fj-IMRT plans were significantly lower than those in sf-IMRT plans, with statistical differences (P<0.05). The two plans had the same number of fields, and the monitor units in sf-IMRT plans were lower than those in fj-IMRT plans ［(997.12±209.73) MU vs (1 081.98±241.32) MU, P=0.013］. Conclusion For middle thoracic esophageal carcinoma, fj-IMRT plans significantly reduced the low dose exposure of lungs, heart, and body-PTV compared with sf-IMRT plans, while maintaining the similar target coverage and plan delivery efficiency.