Bar-Ad Voichita, Hubley Emily, Luginbuhl Adam, Cognetti David, Curry Joseph, Harrison Amy S, Johnson Jennifer M, Keller James, Peng Cheng, To David, Doyle Laura
Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, United States.
Department of Otolaryngology, Thomas Jefferson University, Philadelphia, PA, United States.
J Contemp Brachytherapy. 2019 Jun;11(3):227-234. doi: 10.5114/jcb.2019.85778. Epub 2019 Jun 28.
Permanent interstitial brachytherapy is an appealing treatment modality for patients with locoregional recurrent, resectable head and neck carcinoma (HNC), having previously received radiation. Cesium-131 (Cs) is a permanent implant brachytherapy isotope, with a low average photon energy of 30 keV and a short half-life of 9.7 days. Exposure to medical staff and family members is low; patient isolation and patient room shielding are not required. This work presents a single institution's implementation process of utilizing an intraoperative, permanent Cs implant for patients with completely resected recurrent HNC.
Fifteen patients receiving Cs permanent seed brachytherapy were included in this analysis. The process of pre-planning, selecting the dose prescription, seed ordering, intraoperative procedures, post-implant planning, and radiation safety protocols are described.
Tumor volumes were contoured on the available preoperative PET/CT scans and a pre-implant treatment plan was created using uniform source strength and uniform 1 cm seed spacing. Implants were performed intraoperatively, following tumor resection. In five of the fifteen cases, intraoperative findings necessitated a change from the planned number of seeds and recalculation of the pre-implant plan. The average prescription dose was 56.1 ±6.6 Gy (range, 40-60 Gy). The average seed strength used was 2.2 ±0.2 U (3.5 ±0.3 mCi). Patients returned to a recovery room on a standard surgical floor and remained inpatients, without radiation safety restrictions, based on standard surgical recovery protocols. A post-implant treatment plan was generated based on immediate post-operative CT imaging to verify the seed distribution and confirm delivery of the prescription dose. Patients were provided educational information regarding radiation safety recommendations.
Cesium-131 interstitial brachytherapy is feasible and does not pose major radiation safety concerns; it should be considered as a treatment option for previously irradiated patients with recurrent, resectable HNC.
永久性组织间近距离放射治疗对于先前接受过放疗、局部区域复发且可切除的头颈癌（HNC）患者而言是一种有吸引力的治疗方式。铯-131（Cs）是一种永久性植入近距离放射治疗同位素，其平均光子能量低，为30keV，半衰期短，为9.7天。医护人员和家庭成员所受辐射暴露低；无需对患者进行隔离以及对病房进行屏蔽。本文介绍了一家机构对完全切除的复发性HNC患者采用术中永久性Cs植入的实施过程。
本分析纳入了15例接受Cs永久性籽源近距离放射治疗的患者。描述了术前规划、选择剂量处方、订购籽源、术中操作、植入后规划以及辐射安全方案的过程。
在可用的术前PET/CT扫描上勾勒出肿瘤体积，并使用均匀的源强和均匀的1cm籽源间距创建植入前治疗计划。在肿瘤切除后进行术中植入。15例病例中有5例，术中发现需要改变计划的籽源数量并重新计算植入前计划。平均处方剂量为56.1±6.6Gy（范围40 - 60Gy）。所使用的平均籽源强度为2.2±0.2U（3.5±0.3mCi）。患者返回标准外科楼层的恢复室，根据标准外科恢复方案，作为住院患者留院，无辐射安全限制。根据术后即刻CT成像生成植入后治疗计划，以验证籽源分布并确认处方剂量的给予。向患者提供了有关辐射安全建议的教育信息。
铯-131组织间近距离放射治疗是可行的，且不存在重大辐射安全问题；对于先前接受过放疗的复发性、可切除HNC患者，应将其视为一种治疗选择。
