Zhao Zhipeng, Zhang Ning, Liu Ying, Wu Ning, Mao Zhuang, Yang Wei, Cheng Guanghui
Department of Radiation Oncology, China-Japan Union Hospital of Jilin University, Changchun, China.
J Contemp Brachytherapy. 2020 Jun;12(3):252-259. doi: 10.5114/jcb.2020.96866. Epub 2020 Jun 30.
To analyze the results of clinical utilization of ring applicator for combined intracavitary (IC)/interstitial (IS) image-guided brachytherapy (BT) technique in locally advanced cervical cancer (LACC), and to explore the application conditions of IC/IS BT approach with this applicator for Chinese patients.
IC/IS BT was performed in total of 95 LACC patients, who already received external beam radiotherapy. In forty-three of these patients, utilization of ring applicator in brachytherapy was done, including IC/IS BT approach with ring applicator for 65 fractions. Clinically optimized IC/IS BT plan with ring applicator (IC/IS treatment) and additionally generated optimized plan without needle use (IC research) were designed, respectively. Dosage differences in target regions and organs at risk (OARs) were analyzed between both the plans. Four planes were selected in the longitudinal direction of uterine cervix and divided the 360° area around the tandem into eight equal sectors. Tumor target features and prescription dose distributions on different planes were described.
The usage rate of ring applicator with most suitable ring diameter of 26 mm was 45.3% in Chinese cervical cancer patients. The high-risk clinical target volume (HR-CTV) D/D and intermediate-risk CTV (IR-CTV) D/D in IC/IS treatment were significantly higher than IC research. As compared with IC research plan, the D of bladder and rectum in IC/IS treatment were significantly lower ( < 0.05). There was no significant difference in D of sigmoid and small bowel between two plans. When the target volume was larger than 36 cm, IC alone had an inadequate coverage of target.
Nearly half of Chinese patients with LACC could be treated with the ring applicator. The application conditions of IC/IS BT approach with ring applicator for Chinese patients were achieved. Combined IC/IS image-guided BT based on magnetic resonance imaging (MRI) planning is clinically feasible in Chinese patients.
分析环形施源器在局部晚期宫颈癌（LACC）腔内（IC）/组织间（IS）图像引导近距离放疗（BT）技术中的临床应用结果，探讨该施源器用于中国患者的IC/IS BT方法的应用条件。
对95例已接受外照射放疗的LACC患者进行IC/IS BT。其中43例患者在近距离放疗中使用了环形施源器，包括使用环形施源器进行IC/IS BT共65次分割。分别设计了临床优化的带环形施源器的IC/IS BT计划（IC/IS治疗）和额外生成的不使用针的优化计划（IC研究）。分析两个计划在靶区和危及器官（OARs）的剂量差异。在子宫颈纵向上选择四个平面，并将串联周围的360°区域分成八个相等的扇形区。描述不同平面上的肿瘤靶区特征和处方剂量分布。
在中国宫颈癌患者中，最适合的环形直径为26 mm的环形施源器使用率为45.3%。IC/IS治疗中的高危临床靶区体积（HR-CTV）D/D和中危CTV（IR-CTV）D/D显著高于IC研究。与IC研究计划相比，IC/IS治疗中膀胱和直肠的D显著更低（<0.05）。两个计划之间乙状结肠和小肠的D无显著差异。当靶区体积大于36 cm时，单纯IC对靶区的覆盖不足。
近一半的中国LACC患者可用环形施源器治疗。实现了环形施源器用于中国患者的IC/IS BT方法的应用条件。基于磁共振成像（MRI）规划的IC/IS图像引导BT在中国患者中临床可行。
