Heavy-ion tumor therapy: Physical and radiobiological benefits
Heavy-ion tumor therapy: Physical and radiobiological benefits
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DOI：
10.1103/revmodphys.82.383
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发表时间：
2010-01-01
影响因子：
44.1
通讯作者：
Schulz-Ertner, Daniela
中科院分区：
文献类型：
--
作者：
Schardt, Dieter;Elsaesser, Thilo;Schulz-Ertner, Daniela
与传统的兆伏光子疗法相比，高能带电核粒子束（质子和较重的离子）为治疗深部局部肿瘤提供了显著的优势。它们在组织中的物理深度剂量分布的特征在于小的入射剂量和接近范围末端的明显最大值（布拉格峰），在远端边缘处急剧下降。现代扫描射束系统充分利用了定义明确的范围和较小的横向射束扩展，可实现毫米级精度的剂量输送。此外，比质子重的射弹如碳离子在布拉格峰区域表现出增强的生物有效性，这是由单个粒子径迹的密集电离引起的，从而导致细胞修复减少。这使得它们对于治疗位于危险器官附近的放射抗性肿瘤特别有吸引力。虽然质子肿瘤治疗是一种成熟的治疗方式，全球有超过60 000名患者接受治疗，但迄今为止，重离子的应用仅限于少数设施。然而，临床I-II期试验的结果提供了证据，表明碳离子放射治疗可能对几种肿瘤实体有益。本文综述了重离子治疗的物理和技术进展、放射生物学研究和模型以及放射肿瘤学研究。由于在过去十年中在重离子医用加速器设施（日本）和GSI达姆施塔特（德国）的一个试点项目中用碳离子束获得了有希望的临床结果，最近重离子或质子和重离子联合治疗的新临床中心的计划得到了实质性的推动。
High-energy beams of charged nuclear particles (protons and heavier ions) offer significant advantages for the treatment of deep-seated local tumors in comparison to conventional megavolt photon therapy. Their physical depth-dose distribution in tissue is characterized by a small entrance dose and a distinct maximum (Bragg peak) near the end of range with a sharp fall-off at the distal edge. Taking full advantage of the well-defined range and the small lateral beam spread, modern scanning beam systems allow delivery of the dose with millimeter precision. In addition, projectiles heavier than protons such as carbon ions exhibit an enhanced biological effectiveness in the Bragg peak region caused by the dense ionization of individual particle tracks resulting in reduced cellular repair. This makes them particularly attractive for the treatment of radio-resistant tumors localized near organs at risk. While tumor therapy with protons is a well-established treatment modality with more than 60 000 patients treated worldwide, the application of heavy ions is so far restricted to a few facilities only. Nevertheless, results of clinical phase I-II trials provide evidence that carbon-ion radiotherapy might be beneficial in several tumor entities. This article reviews the progress in heavy-ion therapy, including physical and technical developments, radiobiological studies and models, as well as radiooncological studies. As a result of the promising clinical results obtained with carbon-ion beams in the past ten years at the Heavy Ion Medical Accelerator facility (Japan) and in a pilot project at GSI Darmstadt (Germany), the plans for new clinical centers for heavy-ion or combined proton and heavy-ion therapy have recently received a substantial boost.