Forward IMRT planning of nasopharyngeal carcinoma by field aperture shape optimazing based beam direction / 中华放射肿瘤学杂志

ABSTRACT

Objective To evaluate and summarize a new way of forward intensity modulated radia- tion therapy (IMRT) plan for nasopharyngeal carcinoma with 3Dmulti-leaf collimator (MLC) planning sys- tems is practised routinely in our department.Methods From September 2000 to July 2003 and November 2005 to March 2006,78 patients with nasopharyngeal carcinoma who were treated with eonformal radiothera- py used CT simulation for localizing,then doctors supervised the delineation of the planned tumor volume (PTV),gross tumor volume (GTV) and other sensitive organs on ACQsim workstation,and then sent the CT imagines to ELEKTA Precise Plan by DICOM RT Ethernet.Then,the physicists take over the responsibility of all directions of beam projection according to these organs and PTV shape,and completed the IMRT plan by manual correction making and the optimization of fields or segments shaped with forward 3D planning sys- tem.Results To analyse all the patient's dose distributions taking conformal radiotherapy in our hospital, we found the dose distribution and DVH data excellent,even better than the inverse planning of nasopharyn- geal carcinoma.Conclusions Intensity modulated radiation therapy (IMRT) is an advanced radiotherapy technique.A very good IMRT plan of nasopharyngeal carcinoma by forward planning can be obtained with 3D multiple leaf collimator (MLC) planning system.This planning method is more flexible,but the radia- tion physicists should be very much experienced in professional skill.