Radiotherapy should have low toxicity in the entrance channel (normal tissue) and be very effective in cell killing in the target region (tumour). In this regard, ions heavier than protons have both physical and radiobiological advantages over conventional X-rays. Carbon ions represent an excellent combination of physical and biological advantages. There are a dozen carbon-ion clinical centres in Europe and Asia, and more under construction or at the planning stage, including the first in the USA. Clinical results from Japan and Germany are promising, but a heated debate on the cost-effectiveness is ongoing in the clinical community, owing to the larger footprint and greater expense of heavy ion facilities compared with proton therapy centres. We review here the physical basis and the clinical data with carbon ions and the use of different ions, such as helium and oxygen. Research towards smaller and cheaper machines with more effective beam delivery is necessary to make particle therapy affordable. The potential of heavy ions has not been fully exploited in clinics and, rather than there being a single ‘silver bullet’, different particles and their combination can provide a breakthrough in radiotherapy treatments in specific cases.

放射治疗应在入口通道（正常组织）中具有低毒性，并且对靶区（肿瘤）的细胞杀伤非常有效。在这方面，比质子重的离子比传统的 X 射线具有物理和放射生物学优势。碳离子代表了物理和生物学优势的完美结合。欧洲和亚洲有十几个碳离子临床中心，还有更多正在建设或规划阶段，其中包括美国的第一个。日本和德国的临床结果很有希望，但由于与质子治疗中心相比，重离子设施占地面积更大，费用更高，因此临床界仍在就成本效益展开激烈辩论。我们在这里回顾了碳离子的物理基础和临床数据以及不同离子的使用，比如氦气和氧气。有必要研究更小、更便宜且具有更有效光束传输的机器，以使粒子疗法负担得起。重离子的潜力尚未在临床上得到充分发挥，在特定病例中，不同的粒子及其组合可以为放射治疗提供突破，而不是单一的“银弹”。