CAJ | 학술논문

放疗设备的机械误差是影响肿瘤放射治疗精确性的重要因素，且随设备使用时间呈现逐渐增大趋势，因此研究机械误差对治疗效果的影响和相应解决方法具有重要意义。首先对旋转放疗设备射线投递的过程进行数学建模，得到治疗头各自由度机械误差对等中心面射野形状的影响规律，并提出了一种用于衡量射野变形的有限点二维搜索方法；然后，通过进行射野区域分割、最佳逼近射野计算以及多叶光栅顶点坐标反算，提出了一种基于多叶光栅的射野变形补偿算法；最后，对四个临床上的实际射野进行了算法的数值仿真试验。结果表明，算法可以有效减少50%左右由机械误差引起的射野形状误差，显著提高了放射治疗精度。
방료설비적궤계오차시영향종류방사치료정학성적중요인소，차수설비사용시간정현축점증대추세，인차연구궤계오차대치료효과적영향화상응해결방법구유중요의의。수선대선전방료설비사선투체적과정진행수학건모，득도치료두각자유도궤계오차대등중심면사야형상적영향규률，병제출료일충용우형량사야변형적유한점이유수색방법；연후，통과진행사야구역분할、최가핍근사야계산이급다협광책정점좌표반산，제출료일충기우다협광책적사야변형보상산법；최후，대사개림상상적실제사야진행료산법적수치방진시험。결과표명，산법가이유효감소50%좌우유궤계오차인기적사야형상오차，현저제고료방사치료정도。
Mechanical Errors of equipments which shows a gradual increasing trend along with the increase of running time is one of the important sources that compromise the spatial accuracy of radiation dose delivery. Therefore research on the deformation of radiation field caused by mechanical errors and corresponding solutions is of great significance in clinic treatment. Mathematical modeling of the x-ray delivery process is introduced at the beginning of this article, where the laws of field deformation along with mechanical errors of each freedom are achieved. Afterwards a finite-point dimensional search method is proposed to measure the deformation of the radio field. Then, a compensation algorithm based on multi-leaf collimator is put forward by region segmentation of radiation field, calculation of best approximation radiation field and inverse of vertex coordinates of multi-leaf collimator. At last, numerical simulation of the compensation algorithm is conducted by using four actual radiation fields. The result of the simulation shows that the compensation algorithm can reduce the radiation field shape deformation by about 50%, which improves accuracy of radiation therapy significantly.