Evaluation of three different CT simulation and planning procedures for the preoperative irradiation of operable rectal cancer.

Purpose: To find the best procedure regarding quality and work load for treatment planning in operable non-locally advanced rectal cancer using 3D CT-based information.

Methods: The study population consisted of 62 patients with non-locally advanced tumours, as defined by MRI in the lower (N=16), middle (N=25) and upper (N=21) rectum referred for preoperative short-course radiotherapy. In procedure 1 (Pr1), planning in one central plane was performed (field borders/shielding based on bony anatomy).