Ell C, Hochberger J, Fietkau R, Schneider T, Schmitt M, Hahn E G
Department of Medicine I, Friedrich-Alexander-University, Erlangen-Nuremberg, Germany.
Endoscopy. 1993 Mar;25(3):236-9. doi: 10.1055/s-2007-1010299.
Applicators used to date in endoluminal "high dose rate" (HDR) afterloading (AL) radiotherapy of esophageal carcinoma consist of hollow plastic probes with an average thickness of 4 mm (1.8-5.0 mm), the diameter of which, however, often strongly deviates from that of the lumen of the tumor stenosis. Consequently, the probe can occupy an eccentric position in the esophagus. Exact dosimetry in the tumor region thus becomes virtually impossible, since the dose of the iridium emitter drops significantly with increasing distance (> 60% at a distance of 5 mm from the surface of the 4 mm probe). The bougie-type afterloading applicators developed by our group, however, offer a number of distinct advantages in comparison to conventional applicator probes: 1. Precise positioning of the applicator in the stenosis with simultaneous bougie effect. 2. Exact centering of the radiation source in the lumen of the esophagus. 3. Individual adaptation of the applicator size to the diameter of the residual lumen resulting from the tumor. 4. Upon patient-specific adaptation of the radiation exposure period, a distinct reduction of the surface (mucosa) dose is achieved together with simultaneous enhancement of the depth effect of radiotherapy treatment. Using these new afterloading bougies in over 150 treatment sessions involving 55 patients, no complications were thus far observed.
以往用于食管癌腔内“高剂量率”（HDR）后装放疗的施源器由平均厚度为4毫米（1.8 - 5.0毫米）的中空塑料探头组成，但其直径往往与肿瘤狭窄腔的直径有很大偏差。因此，探头在食管中可能处于偏心位置。由于铱放射源的剂量会随着距离增加而显著下降（距离4毫米探头表面5毫米处剂量下降超过60%），肿瘤区域的精确剂量测定实际上变得不可能。然而，我们团队研发的探条式后装施源器与传统施源器探头相比具有许多明显优势：1. 施源器在狭窄部位精确就位，同时起到探条作用。2. 放射源在食管腔内精确对中。3. 施源器尺寸可根据肿瘤导致的残余腔直径进行个体化适配。4. 根据患者具体情况调整放射暴露时间，可显著降低表面（黏膜）剂量，同时增强放射治疗的深度效应。在涉及55例患者的150多次治疗中使用这些新型后装探条，目前尚未观察到并发症。
