The purpose of this study was to investigate the ability of a management system\n(Delivery Analysis: DA) to detect intrafractional motion during intensity-\nmodulated radiation therapy (IMRT) in tomotherapy mode. Tomotherapy\nhas made it possible to manage internal movements during treatment using\nsoftware DA, which quantifies using the information of the passing dose obtained\nduring the radiation treatment of patients. First, three treatment plans\nfor the test were created (lumbar spine, prostate, and femur). Second, a pelvis\nphantom was moved in the X, Y, and Z directions, and a sinogram was acquired.\nThe magnitudes of the movements were 3 mm, 5 mm, and 10 mm,\nrespectively. Finally, the ability of DA to detect the motion was evaluated by\ncomparing the sinogram obtained by moving the phantom with a reference\nsinogram obtained without movement. The sensitivity of DA could be detected\nwith a shift amount of 3 mm (gamma analysis tolerance 0.3 mm/0.3%).\nThe average gamma analysis of each direction at 0.3 mm/0.3% tolerance at\neach treatment site was 96.1% for the prostate, 93.5% for the lumbar spine,\nand 94.4% for the femur. Additionally, the average gamma pass rate results\nfor the pelvic phantom in the X, Y, Z directions for a 10 mm shift were 96.2%,\n96.3%, and 95.9%, respectively. DA is a powerful tool with high detection\nsensitivity and ability to detect body movement during treatment.
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