Radiotherapy (RT), including external beam RT and internal radiation therapy, uses high-energy ionizing radiation to kill tumor cells. However, ionizing radiation inevitably damages the surrounding normal tissues. Therefore, it is imperative to develop precision RT for improving the treatment outcome and reducing the adverse effects. Recent breakthroughs in nanotechnology have provided a variety of strategies by which RT can precisely and efficiently eradicate local tumors. In this review, we would like to summarize a series of nanotechnology-mediated strategies to achieve precision RT, including tumor-targeted delivery, image-guided precision radiotherapy, and exo/endogenous stimuli-responsive nanomedicines for enhanced tumor accumulation/penetration. In addition, this review will also discuss two representative featured applications of precision RT: RT-induced immunotherapy against cancer metastasis and radioprotection of the surrounding healthy tissues. Since RT is usually thought to be only effective for treating local tumors, this review will interpret the unusual mechanisms of RT-mediated systemic antitumor immunity for eliminating distant cancer metastasis as well as the abscopal effects of RT in combination with other treatments (e.g., photodynamic therapy (PDT), chemodynamic therapy (CDT), etc.). Furthermore, this review will discuss nanotechnology-mediated radioprotection strategies for shielding healthy tissues from radiation damage. Finally, the current challenges and future prospects of precision RT are also elucidated with the intention to accelerate its clinical translation.

中文翻译：

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开发纳米技术介导的抗转移和辐射防护精准放疗

放疗 (RT)，包括外照射放疗和内部放疗，使用高能电离辐射来杀死肿瘤细胞。然而，电离辐射不可避免地会损伤周围的正常组织。因此，开发精准放疗以提高治疗效果和减少不良反应势在必行。纳米技术的最新突破提供了多种策略，放疗可以通过这些策略精确有效地根除局部肿瘤。在这篇综述中，我们想总结一系列纳米技术介导的策略来实现精确放疗，包括肿瘤靶向递送、图像引导精确放疗和用于增强肿瘤积累/渗透的外/内源性刺激响应纳米药物。此外，本综述还将讨论精准放疗的两个具有代表性的特色应用：放疗诱导的癌症转移免疫疗法和周围健康组织的辐射防护。由于放疗通常被认为只对治疗局部肿瘤有效，这篇综述将解释放疗介导的全身抗肿瘤免疫消除远处癌症转移的不寻常机制，以及放疗与其他治疗相结合的远隔效应（例如，光动力疗法(PDT)、化学动力疗法(CDT)等。此外，这篇综述将讨论纳米技术介导的辐射防护策略，以保护健康组织免受辐射损伤。最后，还阐述了精准放疗目前面临的挑战和未来前景，以期加速其临床转化。