内镜超声引导下^125I粒子腹腔神经节照射近期安全性评价的实验研究

Evaluation of safety of celiac plexus brachytherapy with ^125 seeds placement guided by endoscopic ultrasound in porcine model

目的观察EUS引导下^125I粒子腹腔神经节照射对大血管及周围脏器的影响。方法14只家猪随机分成4组：A组，空粒子种植对照；B组及C组分别选择放射活度为0．4mCi（1．48×10^7Bq）和0．8mCi（2．96×10^7Bq）的^125I粒子种植；D组行无水乙醇腹腔神经节阻滞术。A、B、C3组术后摄腹部平片和CT增强扫描以及血管三维重建辅助判断种植的准确性，D组单侧注射无水乙醇5ml，检测血常规、肝肾功能、血淀粉酶以及CD4^＋／CD8^＋值。观察期结束后处死，解剖观察粒子在位情况，取粒子周围组织、脏器送病理检测。结果A组1只与C组中1只种植失败（16．7％），隔日再行补种均成功，其余粒子均一次性植入，定位良好，除C组中1只术后7d出现白细胞升高，解剖发现局部小脓肿形成外，其余家猪血常规、肝肾功能、血淀粉酶以及CD4^＋／CD8^＋值穿刺前后均无差异。病理检测显示周围脏器均无异常发现，与对照组相比，^125I粒子照射的血管外膜有变性坏死，并伴随轻微炎性反应，周围有纤维组织增生，程度随照射剂量及照射时间的增加而略有加重，血管肌层、内膜均未受任何影响，血管内未见血栓形成。注射无水乙醇的家猪解剖发现其腹腔干呈淡褐色，较正常粗大，病理发现血管外膜及周围纤维结缔组织坏死出血明显，大量炎症细胞浸润。结论放射性粒子对周围脏器没有影响，不会损害其免疫功能，对血管有一定的损伤作用，但作用有限，较无水乙醇对血管的损伤小，因此EUS引导下^125I粒子腹腔神经节照射是安全的。

Objective To assess the safety of celiac plexus brachytherapy with ^125I seeds placement guided by endoscopic ultrasound in porcine model, and to evaluate its effect on surrounding vessels and organs. Methods Fourteen pigs were randomly divided into 4 groups to accept celiac plexus block by bilateral injection with 2 non-radioactive seeds in group A （ n = 4） , 0.4 mCi seeds in Group B （ n = 4） , 0. 8 mCi seeds in Group C （ n = 4） and one lateral injection with 5 ml dehydrated alcohol, respectively. Abdominal X- ray, Enhanced CT and three-dimensional reconstruction of blood vessels were performed to confirm the proper placement of the seeds in group A,B and C. Routine blood test, liver and renal function, serum amylase and CD4 ^＋/CD8 ^＋ ratio were examined preoperatively and at the end of the follow-up in all groups. Animals were euthanized in batch to observe the position of the implanted seeds. Tissues and organs around the seeds were dissected for pathological examination. Results The procedure succeeded in 12 pigs （85.7%） and failed in two others （ 1 in group A, and 1 in C） due to inappropriate position. Rescue procedures were performed on another day and succeeded. No significant difference was found in routine blood test, liver and renal func- tion, serum amylase and CD4 ^＋/CD8 ^＋ ratio, except WBC elevation and small abeesses were found 7 days after the procedure in one pig of group C. In the radiated area, there was degeneration, necrosis and mild inflammation at the outer membrane of blood vessels, with fibrosis around, which was positively correlated withthe radiation dosage and duration. There was no change at the muscular layer and the innermost membrane of blood vessels, and no thrombosis was found. In group D, the celiac trunk became slightly brown and wider with obvious hemorrhage, necrosis and infiltration of inflammatory ceils in the outer membrane of blood vessles and connective tissues around. Conclusion Brachytherapy has little negative effect on the organs around. It does not harm immunnity but induces lesions in blood vessels. Compared with dehydrated alcohol, this negative effect is limited. Therefore, celiac plexus brachytherapy with ^125I seeds guided by endoscopic ultrasound is safe.