Liu Zhongshan, Zhao Yangzhi, Li Yunfeng, Sun Jing, Lin Xia, Wang Tiejun, Guo Jie
Department of Radiation Oncology, The Second Affiliated Hospital of Jilin University Changchun 130041, China.
Department of Hematology, The First Hospital of Jilin University Changchun 130021, China.
Am J Cancer Res. 2020 Dec 1;10(12):4165-4177. eCollection 2020.
Brachytherapy (BT) delivers integrated boost doses to the central tumor while sparing the surrounding organs at risk (OARs) efficiently. It's a mandatory treatment component for locally advanced cervical cancer (LACC) because it results in excellent overall survival and local control compared with other dose boosting modalities. Currently, BT is undergoing a transition from 2-dimensional (2D) to 3-dimensional (3D) treatment planning. Imaging-guided BT (IGBT) employing computed tomography (CT) or magnetic resonance imaging (MRI) can provide exact individual delineation of target and OARs meanwhile prescribe the dose to the target volume instead of "point A" for X-ray-based BT. There are three main techniques for BT: intracavitary (IC), interstitial (IS), and intracavitary/interstitial (IC/IS) combination. The applicator choice depends on the specific tumor extension. The real-time transabdominal ultrasound (US)-guided applicator placement technique is strongly recommended to ensure ideal applicator positioning. MRI is the ideal standard imaging for BT owing to its superior soft tissue visualization than CT. However, CT-based BT is more often performed because of the availability. In developing countries, US-based BT can be adopted. For treatment planning, the applicator reconstruction is easier on CT than on MRI, because the applicator image is more clearly visible. Individual treatment planning should be performed for every single applicator insertion to ensure dose accuracy. In this review article, we explain the main clinical process and common techniques, including the applicator choice and placement, imaging techniques, target delineation, and treatment planning; asthose will help to improve the efficiency of 3D BT.
近距离放射治疗（BT）可向中央肿瘤提供整合的增敏剂量，同时有效地保护周围的危及器官（OARs）。对于局部晚期宫颈癌（LACC），它是一种必不可少的治疗组成部分，因为与其他剂量增强方式相比，它能带来出色的总生存率和局部控制率。目前，BT正从二维（2D）治疗计划向三维（3D）治疗计划转变。采用计算机断层扫描（CT）或磁共振成像（MRI）的影像引导BT（IGBT）能够同时精确地对靶区和OARs进行个体化勾画，并向靶区体积而非基于X线的BT中的“A点”规定剂量。BT有三种主要技术：腔内（IC）、组织间（IS）以及腔内/组织间（IC/IS）联合。施源器的选择取决于肿瘤的具体扩展情况。强烈推荐采用实时经腹超声（US）引导的施源器放置技术，以确保施源器理想的定位。由于MRI在软组织可视化方面优于CT，所以它是BT的理想标准成像方式。然而，基于CT的BT因可用性更高而更常被采用。在发展中国家，可以采用基于US的BT。对于治疗计划而言，基于CT的施源器重建比基于MRI的更容易，因为施源器图像在CT上更清晰可见。应对每一次施源器插入进行个体化治疗计划，以确保剂量准确性。在这篇综述文章中，我们解释了主要的临床过程和常用技术，包括施源器的选择和放置、成像技术、靶区勾画以及治疗计划；因为这些将有助于提高3D BT的效率。
