RESUMO
PURPOSE: The purpose of this study was to evaluate the feasibility and efficacy of beta-radiation therapy with a rhenium-188-mercaptoacetyltriglycine ((188)Re-MAG(3)) filled balloon to prevent tissue hyperplasia secondary to stent placement in a rabbit esophageal model. MATERIALS AND METHODS: Fifteen rabbits were divided into the three study groups. The ten rabbits having the radioactive balloon dilation performed immediately after stent placement were scheduled to be sacrificed at six weeks; the 20 Gy (Group I, n=5) or 40 Gy (Group II, n=5) at 1 mm away from the balloon surface were also sacrificed at six weeks. The remaining five rabbits that had conventional balloon dilation done immediately after stent placement were scheduled to be sacrificed six weeks later; this was the control group (Group III). At follow-up, we obtained esophagography and the histologic findings (epithelial layer thickness, degree of destruction of the muscularis propria, and degree of submucosal inflammatory cell infiltration) at both the normal area and the mid-stent area for each esophageal specimen after sacrificing each rabbit. The differences among the three groups were statistically assessed using Kruskal-Wallis and Mann-Whitney U tests. RESULTS:There were no complications such as migration after stent placement. Nine of the rabbits died 1-3 weeks after stent placement and the stents were partially obstructed with a lot of residue, so it was impossible to compare the esophagographic findings among the three groups. Esophageal perforation (n=6) and mucosal reddish changes (n=5) of the esophagus adjacent to the stent were observed only for rabbits of group I or II. The esophageal mucosa displayed smoothness in group I and II, and the esophageal mucosa displayed nodularity in group III. The degree of destruction of the muscularis propria was significantly higher in group I or II when compared to group III (p<0.05). CONCLUSION: Beta-irradiation using a (188)Re-MAG(3)-filled balloon dilation has the potential for preventing tissue hyperplasia secondary to stent placement in a rabbit esophageal model.
