一种新型可调充气式鼻咽后装施源器的研制和应用

A New Applicator with Regulatable Air Bag Designed for Intracavitary Brachytherapy of Nasopharyngeal Carcinoma

背景与目的:鼻咽腔内近距离放疗施源器(以下简称施源器)在鼻咽腔内近距离放疗中起重要作用,直接影响治疗的效果。我们研制了一种新型施源器。方法:新型施源器用医用乳胶材料制成,在距施源器前端15mm处置一气囊,气囊边缘与管轴相切,紧贴于管壁一侧,令充气时管轴反向拱形隆起贴近治疗部位。使用时经中鼻道达后壁,通过旋转施源器可调节施源器方向和位置,经注气孔注入空气并固定。治疗前需复核定位证实。结果:共治疗221例鼻咽癌,初治病例中鼻咽肿物消退率92.6%,复发病例鼻咽肿物全部消退,鼻咽前壁或后壁粘膜坏死5例,鼻甲水肿及后鼻道粘连8例。结论:本施源器具有安全可靠,操作方便,患者无痛苦,剂量分布理想,固定性较好等优点。在治疗中出现鼻咽粘膜坏死可能与初期使用时单次剂量过高有关。

BACKGROUND &OBJECTIVE: Nasopharynx applicator used in intracavitar y brachytherapy plays an important role in the radiotherapy of nasopharyngeal ca rcinoma (NPC), its quality affects the efficiency of treatment. This study was t o design a new applicator for clinical use. METHODS: An inexpensive, reusable, a nd flexible latex nasopharynx applicator was designed. An air bag was placed at 15 mm from the foreside of the applicator, clung to the tube. The edge of air ba g is tangent to the axis of tube. When the bag was full of air, the tube would h unch reversely, close to nasopharyngeal vault. After introduced into nasopharynx through middle nasal meatus, the applicator could be fixed in suitable position by its rotation,and air bag regulation,and confirmed its position by simulation . RESULTS: A total of 221 patients with NPC were treated with external beam radi ation therapy in our hospital, and boosted HDR brachytherapy using this new appl icator. The response rate was 92.6%in the primary tumor group (200/216),and 100 %in the recurrent tumor group (5/5). Mucosal necrosis in the posterior or anter ior wall of nasopharynx occured in 5 patients, 8 patients experienced nasal cong estion and nasal synechia. CONCLUSIONS: This new nasopharynx applicator is easy to operate,painless,and well dosage-distributed. Mucosal necrosis is likely due to higher fractional dose.