Setianegara Jufri, Zhu Ya-Nan, Zhu Mingyao, Badkul Rajeev, Zhao Tianyu, Li Harold, Wang Fen, Akhavan David, Gao Hao, Lin Yuting
Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas, United States of America.
Phys Med Biol. 2025 May 19;70(11):115002. doi: 10.1088/1361-6560/add2cc.
. This study aims to develop and evaluate various treatment clinical proton spatially-fractionated-radiotherapy (pSFRT) planning techniques namely proton GRID (pGRID) and LATTICE (pLATTICE).pSFRT plans (27 Gy(RBE), single-fraction) were initially developed using phantom geometries and created retrospectively for a liver patient previously treated with photon virtual GRID (vGRID). pGRID plans varied in cylinder diameters (= 0.4-1.4 cm) and center-to-center distances (c-t-c = 1.7-3.4 cm) and were evaluated by peak-to-valley dose ratios (PVDRs), equivalent uniform dose (EUD), and.and c-t-c distances matching the vGRID EUD andvalues guided pLATTICE sphere distributions. Various pLATTICE techniques, including different beam numbers, orientations, and sphere arrangements, were investigated. We also explored using collimating brass apertures to enhance the pGRID PVDR.pGRID plans with 3.4 cm c-t-c and 0.4 cmresulted in 2.09%, closely matching vGRID's 1.50%. The resultant pGRID PVDR was 8.92 compared to vGRID's 2.7-3.0. PVDRs were affected by spot sizes with reductions of 15.0% with range shifters and 76.0% from 7.5 cm to 27.5 cm depths. The highest PVDR of 4.17 was achieved with two-field pLATTICE plans with favorable beam angles, with a 44.6% reduction with unfavorable beam orientations and up to 24.7% reductions with an increasing number of beams. Non-maximal pLATTICE sphere packing arrangements increases the PVDR with a decrease inwarranting further investigation. pSFRT plans reduced the healthy liverby 83.6%-90.7% compared to vGRID. Apertures enhanced the PVDR by 170% at the deepest depths but increased the skin Dfrom 26.77 Gy to 54.66 Gy.We developed pGRID and pLATTICE plans, demonstrating that desired plan metrics was achieved by adjusting the geometrical arrangements of SFRT contours. The relative orientation of these contours with beam entrances was crucial for high-quality SFRT plans. pSFRT plans achieved superior PVDRs and better dose sparing to OARs compared to vGRID plans.
本研究旨在开发和评估各种治疗性临床质子空间分割放射治疗（pSFRT）计划技术，即质子GRID（pGRID）和点阵（pLATTICE）。pSFRT计划（27 Gy（RBE），单次分割）最初使用体模几何结构制定，并为先前接受光子虚拟GRID（vGRID）治疗的一名肝脏患者进行回顾性创建。pGRID计划的圆柱直径（= 0.4 - 1.4 cm）和中心距（c - t - c = 1.7 - 3.4 cm）各不相同，并通过峰谷剂量比（PVDRs）、等效均匀剂量（EUD）进行评估，且c - t - c距离与vGRID的EUD相匹配，值指导pLATTICE球体分布。研究了各种pLATTICE技术，包括不同的射束数量、方向和球体排列。我们还探索使用准直黄铜孔径来提高pGRID的PVDR。中心距为3.4 cm且直径为0.4 cm的pGRID计划产生的PVDR为2.09%，与vGRID的1.50%非常接近。与vGRID的2.7 - 3.0相比，最终的pGRID的PVDR为8.92。PVDR受光斑大小影响，使用射程移位器时降低了15.0%，在深度从7.5 cm到27.5 cm时降低了76.0%。具有有利射束角度的双野pLATTICE计划实现了最高的PVDR为4.17，不利射束方向时降低了44.6%，射束数量增加时降低高达24.7%。非最大pLATTICE球体填充排列会增加PVDR，同时降低，值得进一步研究。与vGRID相比，pSFRT计划使健康肝脏剂量降低了83.6% - 90.7%。孔径在最深深度处将PVDR提高了170%，但使皮肤剂量从26.77 Gy增加到54.66 Gy。我们开发了pGRID和pLATTICE计划，表明通过调整SFRT轮廓的几何排列可以实现所需的计划指标。这些轮廓与射束入口的相对方向对于高质量的SFRT计划至关重要。与vGRID计划相比，pSFRT计划实现了更高的PVDR和对危及器官更好的剂量 sparing。
