Dosimetric investigation of non-coplanar field technology in static intensity-modulated radiation therapy for gastric carcinoma / 中国辐射卫生

ABSTRACT

Objective To compare the dosimetric characteristics of non-coplanar and coplanar field technology in static intensity-modulated radiotherapy of gastric cancer patients, so as to provide a reference for clinical radiotherapy plan selection. Methods Thirty-six patients with gastric cancer were selected to receive intensity-modulated radiotherapy in Huanggang Central Hospital, which was designed plan A and B. Group A used 7-field coplanar technology, while Group B used 7-field non-coplanar technology. We compared the differences of the optimized monitor unit, the dosimetry of organs at risk and target areas between group A and group B. Results Both group A and B could meet the requirements of doctors. The homogeneity index (0.14 ± 0.02), the conformity index (0.98 ± 0.01), Dmin (4315.21 ± 16.74) cGy、Dmean (4679.28 ± 28.39) cGy and Dmax(4952.30 ± 33.26) cGy of target areas in group B were better than those of group A. Moreover, the monitor unit of group B was much lower than that of group A, and the difference was statistically significant (P < 0.05). The Dmax, Dmean, V15, V20 and V30 of the left and right kidneys in group B were lower than those of group A. The Dmax (3408.57 ± 46.03) cGy, Dmean (1250.32 ± 14.27) cGy and V20 (44.91% ± 6.67%) of spinal cord and the Dmax (3408.57 ± 46.03) cGy, Dmean (1720.55 ± 17.42) cGy, V20 (25.31% ± 7.78%) and V30 (18.52% ± 1.56%) of small intestine were also lower than those of group A. The differences were statistically significant (P < 0.05). Conclusion The non-coplanar field radiation plan has more advantages in terms of target dose distribution and protection of organs so that it can be more considerably used in the process of planning and design.