Three-dimensional conformal radiotherapy breast cancer planning: An evaluation study comparing two techniques using homemade phantom

Anthropomorphic phantoms, which can provide equivalent human tissue densities, are one of the best solutions for verifying the quality of radiotherapy treatment plans produced by treatment planning systems. The goal of this work was to develop and fabricate a breast phantom to estimate radiation doses to the breast, lung, and surface using radiochromic films (EBT3) for basically two techniques of three-dimensional conformal radiotherapy (3D-CRT) treatment planning. Thirty-two acrylic slices were used to construct the phantom. Cork and Teflon were used to mimic the lung and bone, respectively. Four slots were drilled for dosimetry purposes to allow access to the areas of ionization chamber installation. Both wedged and open of two tangential beams techniques were applied. With a mean deviation of 1.02 ± 1.1, the variation between estimated point doses and measurements using the three ionization chambers ranged from 2.9 to 1.4%. Using 0, 5 and 10 mm boluses, the mean percentage doses on the target surface were 54.7, 88.6 and 91.7% of the prescribed dose (PD), respectively. The homemade phantom was appropriate for conducting quality control (QC) tests for 3D-CRT planning techniques for breast radiotherapy