Introduction of a deformable x-ray CT polymer gel dosimetry system.

摘要: This study introduces the first 3D deformable dosimetry system based on x-ray computed tomography (CT) polymer gel and establishes setup reproducibility, deformation characteristics dose response of system. A N-isopropylacrylamide (NIPAM)-based formulation optimized for CT was used, with a latex balloon serving as container low-density polyethylene polyvinyl alcohol providing additional oxygen barrier. Deformable gels were irradiated 6 MV calibration pattern to determine dosimetric dosimetrically uniform plan spatial uniformity response. Wax beads added each fiducial markers track dosimeters. From positions images reproducibility limits determined. Comparison measurements Monte Carlo calculations found excellent accuracy, comparable that an established non-deformable system, mean discrepancy 1.5% in low-dose gradient region gamma pass rate 97.9% using 3%/3 mm criterion. The dosimeter also showed good overall throughout some discrepancies within 20 mm edge container. Tracking sub-millimetre accuracy is achievable this able deform relax when externally compressed by up 30 mm without sustaining any permanent damage. Internal deformations produced average marker movements 12 mm along direction compression. These shown be reproducible over 100 consecutive deformations. work has several important new which shows promise future clinical applications, including validation accumulation algorithms.