On-line Setup for Lung Cancer Patient in Stereotactic Radiation Surgery using CBCT

ABSTRACT

PURPOSE: On-line setup procedure was performed before treatment for lung cancer patient for stereotactic radiation surgery (SRS) using recently introduced Cone Beam CT. MATERIALS AND METHODS: Cone Beam CT was performed for 10 patients who did SRS during 18 July and 1 September, 2006 using On Board Imager (OPB) system made by Varian, USA. The treatment position of patient was corrected comparing Images obtaining from CBCT and used in treatment planning. RESULTS: Comparing the CBCT images and CT images used in treatment planning, the movement of the couch is 2.3+/-2.3 mm, 1.8+/-2.8 mm, 0.3+/-3.5 mm for vertical, lateral, and longitudinal direction. It took about 1 hr for conventional treatment procedure in image acquisition of CT before treatment and image registration. But it took about 4~7 minute in on-line setup using CBCT (1~2 min for image acquisition using CBCT, 2~3 min for CT reconstruction of 2.5 mm slice thickness, 1~2 min for on-line setup using image registration). CONCLUTION The accurate treatment could be performed after tumor localization for SRS using CBCT images. And the consumed time for tumor localization was reduced significantly.