Influence of NiTi metal-stent on radiation dosimetry in esophageal carcinoma
- VernacularTitle:食管内置网状金属支架对放射治疗剂量的影响
- Author:
Shuchai ZHU
;
Fushan ZHAI
;
Chun HAN
- Publication Type:Journal Article
- Keywords:
Esophageal metal-stent;
Radiotherapy dose;
Wax phantom
- From:
Chinese Journal of Radiation Oncology
1992;0(04):-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To study the dose distribution of intra-cavitary NiTi metal-stent for correction in radiotherapy of esophageal carcinoma.Methods Thermoluminescence Dosimeter(TLD) with LiF dose units was used to simulate the dose variation in wax phantom with or without Chinese and Japanese metal stents in esophageal lumen on 60Co, 4 MV X-ray and 6 MV X-ray machines. The dose distribution on the stent fringe (i.e.,on the esophageal mucosa) was compared with that at the center of esophagus without metal stent.Results When a single anterior field was used to irradiate the esophageal carcinoma, the dose enhancement on the anterior and posterior point of the Chinese metal stent was 16.2% and 7.8% by 60Co,15.4% and 6.8% by 4 MV X-ray and 12.8% and 5.8% by 6 MV X-ray. With the same set-up, the dose enhancement of Japanese stent was 13.0% by 6 MV X-ray. When anterioposterior and posterioanterior (AP/PA) opposing fields were used ,the dose enhancement ratio was 11.7%～24.0%. When three fields from three different directions were used ,the dose were increased by 3.2～16.2%.Conclusions When irradiating esophageal carcinoma with intra-cavitary metal stent,we suggest the fraction dose be below 1.7 Gy when one field is used and not exceed 1.5 Gy when AP/PA fields are used. It is advisable to use the three field technique with the diameter of the stent limited to 1.5 cm.
