Comparison Of Dose Distribution In IMRT And SRT Plans Of Targets In The Lung

[Objective]:To compare the relative advantages between intensity modulated radiotherapy(IMRT) and stereotactic radiotherapy(SRT) given their dose distribution in targets in the lung.Findings of this study provided evidence for the purpose of selecting optimal clinical solutions.[Methods and Materials]:SRT plans were designed for 16 patients with lung tumors in cancer hospital of CAMS,who received hypofractioned IMRT from April 2007 to April 2008.The IMRT and SRT plans were compared in terms of dose distribution,conformal index(CI) and homogeneity index(HI).[Results]: The mean dose of planing target volume(PTV) in hypofractioned IMRT was 6282.1±192.4 cGy,and in hypofractioned SRT 6340.6±101.6 cGy.Mean dose of PTV is similar in hypofractioned IMRT and SRT.SRT was available only if PTV was no more than 8 cm~3,which had satisfactory CI.Mean dose of total lung in hypofractioned IMRT was 492.4±368.5 cGy,and 310.0±73.1 cGy in hypofractioned SRT.There is difference between them(p＜0.05).V20 of SRT and IMRT was 6.9±2.1%,4.2±1.9%,respectively(p＜0.01).IMRT and SRT made no difference with respect of mean dose of heart and spinal cord.[Conclusions]:When PTV was more than 57cm~3,SRT should be avoided for its unsatisfactory dose distribution.However,when PTV was less than 57cm~3, hypofractioned SRT was more preferable to hypofractioned IMRT.