Department of Radiation Oncology, Northwestern Memorial Hospital, Chicago, Illinois 60611.
Excecutive Medical Physics Associates and Biophysics Research Institute of America, Miami, Florida 33179.
Radiat Res. 2020 Dec 1;194(6):665-677. doi: 10.1667/RADE-20-00047.1.
The limits of radiation tolerance, which often deter the use of large doses, have been a major challenge to the treatment of bulky primary and metastatic cancers. A novel technique using spatial modulation of megavoltage therapy beams, commonly referred to as spatially fractionated radiation therapy (SFRT) (e.g., GRID radiation therapy), which purposefully maintains a high degree of dose heterogeneity across the treated tumor volume, has shown promise in clinical studies as a method to improve treatment response of advanced, bulky tumors. Compared to conventional uniform-dose radiotherapy, the complexities of megavoltage GRID therapy include its highly heterogeneous dose distribution, very high prescription doses, and the overall lack of experience among physicists and clinicians. Since only a few centers have used GRID radiation therapy in the clinic, wide and effective use of this technique has been hindered. To date, the mechanisms underlying the observed high tumor response and low toxicity are still not well understood. To advance SFRT technology and planning, the Physics Working Group of the Radiosurgery Society (RSS) GRID/Lattice, Microbeam and Flash Radiotherapy Working Groups, was established after an RSS-NCI Workshop. One of the goals of the Physics Working Group was to develop consensus recommendations to standardize dose prescription, treatment planning approach, response modeling and dose reporting in GRID therapy. The objective of this report is to present the results of the Physics Working Group's consensus that includes recommendations on GRID therapy as an SFRT technology, field dosimetric properties, techniques for generating GRID fields, the GRID therapy planning methods, documentation metrics and clinical practice recommendations. Such understanding is essential for clinical patient care, effective comparisons of outcome results, and for the design of rigorous clinical trials in the area of SFRT. The results of well-conducted GRID radiation therapy studies have the potential to advance the clinical management of bulky and advanced tumors by providing improved treatment response, and to further develop our current radiobiology models and parameters of radiation therapy design.
辐射耐受量的限制常常阻碍了大剂量的应用，这一直是治疗大块原发性和转移性癌症的主要挑战。一种使用兆伏治疗束空间调制的新技术，通常称为空间分割放射治疗（SFRT）（例如，GRID 放射治疗），该技术有意地在整个治疗肿瘤体积中保持高度剂量异质性，已在临床研究中显示出作为改善晚期、大块肿瘤治疗反应的方法的潜力。与常规均匀剂量放射治疗相比，兆伏 GRID 治疗的复杂性包括其高度不均匀的剂量分布、非常高的处方剂量以及物理学家和临床医生普遍缺乏经验。由于只有少数中心在临床上使用了 GRID 放射治疗，因此该技术的广泛有效应用受到了阻碍。迄今为止，观察到的高肿瘤反应和低毒性的机制仍未得到很好的理解。为了推进 SFRT 技术和计划，放射外科协会（RSS）的放射治疗工作组、网格/晶格、微束和闪光放射治疗工作组成立了物理工作组。RSS-NCI 研讨会之后。物理工作组的目标之一是制定共识建议，以标准化剂量处方、治疗计划方法、响应建模和 GRID 治疗中的剂量报告。本报告的目的是介绍物理工作组的共识结果，包括将 GRID 治疗作为 SFRT 技术、场剂量学特性、生成 GRID 场的技术、GRID 治疗计划方法、文档指标和临床实践建议的建议。这种理解对于临床患者护理、结果的有效比较以及 SFRT 领域的严格临床试验设计都是必不可少的。精心进行的 GRID 放射治疗研究的结果有可能通过提供改善的治疗反应来推进大块和晚期肿瘤的临床管理，并进一步发展我们当前的放射生物学模型和放射治疗设计参数。
