Dosimetric comparison of conventional and three-dimensional radiotherapy techniques for limited-stage small cell lung cancer

Abstract

Objective To compare the dosimetric difference in planning target volume(PTV)and organ at risk(OAR)with conventional and the three-dimensional treatment planning for limlted-stage small cell lung cancer.Methods Ten patients with limited-stage small cell lung cancer were chosen in the present study.Two treatment planning were designed twice respectively with the Cadplan R 3.1.2 treatment planning system for each patient in two-course.The total radiation dose was 50 Gy.The dosimetric parameters were assessed with dose volume histograms in PIT and OAR.Results For the first course,the dose homogeneity indices(HI)of PTV1,conformal indices(CI)of PTV2,contralateral lung V3o and eontralateral mean lung dose in the three-dimensional treatment planning were better than that in the conventional treatment planning.For the second course,the HI,CI and mean dose of PTV1,CI and mean dose of PTV2 in the three-dimensional treatment planning were better than that in the conventional treatment planning.Conclusions By comparison with conventional treatment planning,the three-dimensional conformal treatment planning could meet the demands of dosimetrie requirements well for limited-stage small cell lung cancer with three-dimensional conformal radiotherapy,but with no significant dnsimetric differences in the OAR. Key words: Limited-stage small cell lung cancer; Three dimensional eonformal radiotherapy; Conventional radiotherapy; Dose volume histograms