Jan Ya-Ting, Chang Chih-Long, Tai Hung-Chi, Huang Yu-Chuen, Liao Chia-Ling, Chen Yu-Jen
Department of Radiology.
Department of Obstetrics and Gynecology.
J Contemp Brachytherapy. 2016 Feb;8(1):82-7. doi: 10.5114/jcb.2016.57803. Epub 2016 Feb 8.
Radiotherapy with concurrent chemotherapy has been recommended as standard treatment for locally advanced cervical cancer. To validate the main tumor location before each high-precision helical tomotherapy (HT) fraction, the development of a more reliable marker or indicator is of clinical importance to avoid inadequate coverage of the main tumor.
A 61-year-old woman with cervical cancer, TMN stage cT2b2N1M1, FIGO stage IVB was presented. Extended field external beam radiotherapy (EBRT) with concurrent chemotherapy and the interdigitated delivery of intracavitary brachytherapy was performed. Helical tomotherapy equipped with megavoltage cone beam computed tomography (MV-CBCT) was used for image-guided radiotherapy. For the insertion of tandem of brachytherapy applicator, a silicone sleeve with a central hollow canal was placed into the endocervical canal with the caudal end stopping at the outer surface of the cervical os, and making contact with the distal boundary of the cervical tumor during the entire brachytherapy course.
In the remaining EBRT fractions, we found that the air cavity inside the central hollow canal of the sleeve could be clearly identified in daily CBCT images. The radiation oncologists matched the bony markers to adjust the daily setup errors because the megavoltage of the CBCT images could not provide a precise boundary between the soft tissue and the tumor, but the sleeve air cavity, with a clear boundary, could be used as a surrogate and reliable marker to guide the daily setup errors, and to demonstrate the primary tumor location before delivery of each HT fraction.
The application of the sleeve during the interdigitated course of HT and brachytherapy in this patient provided information for the feasibility of using the sleeve air cavity as a surrogate marker for the localization of the main primary tumor before the daily delivery of image-guided HT.
同步放化疗已被推荐为局部晚期宫颈癌的标准治疗方法。为在每次高精度螺旋断层放疗（HT）分次治疗前验证主要肿瘤位置，开发一种更可靠的标志物或指标对于避免主要肿瘤覆盖不足具有重要临床意义。
介绍了一名61岁宫颈癌女性患者，TMN分期为cT2b2N1M1，国际妇产科联盟（FIGO）分期为IVB期。进行了同步放化疗的扩大野体外照射放疗（EBRT）以及腔内近距离放疗的交叉施予。配备兆伏级锥形束计算机断层扫描（MV-CBCT）的螺旋断层放疗用于图像引导放疗。在插入近距离放疗施源器的串列时，将一个带有中央空心管的硅胶套管置入子宫颈管，尾端止于宫颈外口表面，并在整个近距离放疗过程中与宫颈肿瘤的远端边界接触。
在剩余的EBRT分次治疗中，我们发现在每日的CBCT图像中可以清晰识别套管中央空心管内的气腔。放射肿瘤学家通过匹配骨标志物来调整每日的摆位误差，因为CBCT图像的兆伏级能量无法提供软组织与肿瘤之间的精确边界，但具有清晰边界的套管气腔可作为替代且可靠的标志物来指导每日的摆位误差，并在每次HT分次治疗前显示原发肿瘤位置。
该患者在HT和近距离放疗交叉过程中应用套管，为在每日图像引导HT治疗前将套管气腔用作主要原发肿瘤定位的替代标志物的可行性提供了信息。
