放射線治療装置における三次元動画計測ソフトウェアを用いたガントリー幾何学的アイソセンタ検証法の考案

摘要

In recent years, development of advanced radiotherapy technology has resulted in an improvement in radiotherapy. Although the radiotherapy system has improved, the effect of the gap, the gyration center, and distortion of the rotation orbit cannot be neglected. Therefore, a verification method for a geometrical isocenter and rotation orbit in a three-dimension (3D) space is required. We developed a verification method for determination of the geometrical isocenter. In this method, the rotation of the gantry that applied the measured target from two directions was imaged and analyzed using animation pursuit analysis software. The measurement targets were pursued by analysis, and the rotation orbit of the target was visually evaluated from obtained coordinates and displacement distance. The gyration center in 3D space was calculated from pursued coordinates and compared with the intersection in the side laser and crosshair. In this verification method, the rotation orbit and geometrical isocenter in the 3D space were confirmed, and visually evaluated. Thus, this method was effective in verifying the geometrical isocenter by solving the problem of the measurement precision and reproducibility.%放射線治療の分野において診療放射線技師の業務は多岐に渡り，その負担は大きなものになっている．特に，放射線治療を効果的に行うには品質管理を怠ることはできず，多大な時間と労力を必要とする．また，近年放射線治療技術の発展によって，放射線治療装置はマルチリーフコリメータや直接備えられたkV X-rayを用いた位置照合システムなどで重量化が進んでいる．加速管など含め数トンにも及ぶガントリーの重量を回転させることによる幾何学的アイソセンタのずれと回転軌道の歪みの経時的な影響は無視できない．