Comparative study of automatic and manual plans of intensity-modulated radiation therapy for nasopharyngeal carcinoma

Abstract

Objective To compare the automatic and manual plans of intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma and investigate whether the automatic plan possesses advantages over the manual plan. Methods Clinical data of 97 nasopharyngeal carcinoma patients were retrospectively analyzed. All patients received IMRT with Eclipse treatment planning system (Version 11.0) using manual optimization. The same plans were optimized successively in Pinnacle3(version 9.10) treatment planning system using automatic plan software package module (provided by Prof. Zhang XD from MD Anderson Cancer Center). The D95(dose in 95% of planning target volume, PTV), homogeneity index, conformal index and normal organ dose were statistically compared between two plans. Results The PTV coverage and homogeneity did not significantly differ between two plans. Compared with the manual plan, the automatic plan could more effectively protect the normal organs. Two plans significantly differed in a majority of organ at risk (OAR). The mean dose was decreased by 270-1870 cGy. Conclusions For nasopharyngeal carcinoma patients, IMRT via the automatic plan can meet the clinical requirement for target prescription dose and reduce the dose of normal organs. Key words: Automatic plan; Manual plan; Nasopharyngeal neoplasms/radiotherapy