Department of Radiation Oncology, National Cancer Center Hospital, Tokyo, Japan.
Jpn J Clin Oncol. 2020 May 5;50(5):490-501. doi: 10.1093/jjco/hyaa029.
Brachytherapy is an invasive therapy with placement of radiation source into or near the tumor. The difference between planning target volume and clinical target volume is minimal, and the dose out of the tumor reduces rapidly due to the inverse-square law. High-dose-rate brachytherapy enables three-dimensional image guidance, and currently, tumor dose as well as doses of the surrounding normal structures can be evaluated accurately. High-dose-rate brachytherapy is the utmost precision radiation therapy even surpassing carbon ion therapy. Biological disadvantages of high-dose rate have been overcome by the fractional irradiation. High-dose-rate brachytherapy is indispensable in the definitive radiation therapy of cervical cancer. Also in prostate cancer and breast cancer, high-dose-rate brachytherapy plays a significant role. Brachytherapy requires techniques and skills of radiation oncologists at the time of invasive placement of the radiation source into the tumor area. Education of young radiation oncologists is most urgent and important.
近距离治疗是一种有创疗法，将放射源置于肿瘤内部或附近。计划靶区与临床靶区之间的差异很小，由于平方反比定律，肿瘤外的剂量迅速降低。高剂量率近距离治疗可实现三维图像引导，目前可以准确评估肿瘤剂量和周围正常结构的剂量。高剂量率近距离治疗是最精确的放疗，甚至超过碳离子治疗。分次照射克服了高剂量率的生物学劣势。高剂量率近距离治疗在宫颈癌的根治性放疗中不可或缺。在前列腺癌和乳腺癌中，高剂量率近距离治疗也发挥着重要作用。近距离治疗需要在将放射源植入肿瘤区域时具备放射肿瘤学家的技术和技能。对年轻的放射肿瘤学家的教育是最紧迫和最重要的。
