ABSTRACT
This study investigated the dosimetric advantages of inversely planned intensity-modulated radiotherapy (IMRT) over forward-planned conventional 3D conformal radiotherapy (3D-CRT) in treating lung cancer patients at escalated dose. Three consecutively accrued patients on the RTOG 93-11 dose-escalation protocol were replanned using IMRT with the same dosimetric rules, so that the isodose distributions and dose-volume histograms could be generated and compared. The Helax-TMS treatment planning system, with an IMRT optimization module (version 6.0), was used. In all cases, a consistent approach of inverse planning and set of dose-volume constraints (DVCs) provided improved critical structure sparing. However, the minimum dose in PTV was generally below that achieved with the corresponding forward planned 3D-CRT.
