Comparison of Dose Distributions for Rectal Cancer Radiotherapy in Two Patient Treatment Positions: Supine and Prone

Abstract

The aim of this study was to compare dose distributions using the Volumetric Modulated Arc Therapy (VMAT) rotational technique for rectal cancer for two patient positions during the irradiation process: supine and abdominal positions. Patients were retrospectively selected into two groups, each group consisting of 10 patients with rectal cancer. For each patient, a VMAT treatment plan was carried out using two or three arcs of 6 MV energy,a TrueBeam linear accelerator, and a set dose of 25 Gy in 5 fractions. The following parameters were analyzed in the plans for the PTV volume: the dose values deposited in 98% and 2% of the PTV volume and the doses received by the critical organs according to the tolerance doses used in the treatment plans. In a group of patients treated for rectal cancer, the VMAT technique in the abdominal position has been shown to reduce intestinal dose by reducing e intestine volume in the irradiation field compared to placing the patient in the supine position. The difference in doses in other critical organs, even the bladder, is insignificant.