| Interstitial implantation of radioactive iodine-125 seeds, one kind of brachytherapy, is a good method which can greatly injury tumor by implanting radioactive sources which can irradiateγrays with low capacity continuously whereas normal tissue is not or slightly injury. Compared with external irradiation, it has many advantages: low strength of radioactive source, short distance of function, strong damage on tumor, small injury to normal tissue, continuous irradiation, high biological effect and therapeutic efficacy predominancely elevate. Many for the urogenital system, head and neck, lung and other organs of the substantive cancer is to utilize. Present iodine-125 seeds implantation in the prostate cancer has been more mature in abroad, and the clinical treatment of the practice in gynecological malignancies , skin and soft tissue malignant tumors,showing a very good therapeutic efficacy, greatly increased in patients with quality of life and prolongs the survival time of patients. In hollow organs such as the gastrointestinal tract, esophagus and other parts of cancer conducted a preliminary study. Gastrointestinal cancer easily cause recurrence and transfer, when patients have lost their chance of operation, the reception dose of the organization gastrointestinal around is low, so the application of radiotherapy is limited. And iodine-125 seeds implantation because of its unique advantages of the biology, there is an application of the gastrointestinal cancer recurrence and transfer.With iodine-125 seeds implantation in a generally applications, peoples pay close attention to its complications. Particularly in the abdominal tumor for iodine-125 seeds implantation when the intestinal tissue of ray sensitive prone to radiation damage. Intestinal tract are an important part of the digestive system, its main function is to digest and absorb. Epithelium mucosae are the most important function, from the composition of intestinal crypts and bloom, both the formation of an updated system. Recess at the base of the stem cells continue to produce epithelial cells migrating to the blooms top, the top falling into the enteric cavity. Therefore, epithelial cell proliferate faster, belong to highly radiation-sensitive organizations. Iodine-125 sustained-release of low energyγ-rays, the characteristics of radiation damage on intestinal, and whether or not same with external radiotherapy is pending further research, in order to avoid radioactive intestinal injury, when iodine-125 seeds implantation adjoin to the gastro -intestinal, Inevitably, the small intestine will produce radioactive damage. Its may appear ankylenteron, intestinal obstruction, perforation, bleeding, increase the chance of intestinal infection. The patient cause unnecessary suffering. How to protective effectively, it's the question which clinicians are concerned about.In this study, iodine-125 seed implantation rabbit intestinal wall, to observe the radiation injury of normal small intestine. we application colic omentum covers the embedding location, to observe the protection of colic omentum to the small intestine, to provide experimental basis for iodine-125 seeds security and protection method in clinical.Objective: To discusses the damage effect of the iodine-125 seeds to rabbit small intestine and the protection of the colic omentum to the small intestine.Methods: 30 health and majority rabbits were chosen. The rabbits were divided into 3 groups randomly, respectively is heat seed sink implants group (A group), pure seed to implant group (B group) and seed implants added colic omentum to pkg group (C group). On the 3 groups of rabbits intestines wall Implants 3 iodine-125 seeds, the triangle arrangement, spacing 0.3 ~ 0.5cm. According compute distribution the target area peripheral dosage was 120Gy. While A group was implanted by the heat sink, B group was implanted by the iodine-125 seed of activity for 2.22×107Bq, C group was implanted after the same method, periphery the colic omentum would fold thick approximately 1cm, covered the target area and fixed. Observation the pathological of small intestine for be apart from target area 0.2cm,0.5 cm,1.0cm and the damage of colic omentum situation at the 14th day and the 30th day. Results: At the 14th day, A group of small intestine hadn't adhered with the periphery tissue. B group had adhered with the periphery tissue, 1 rabbit died, the cause of death was intestinal obstruction, C group was adhered with the colic omentum, had not adhered with the periphery tissue. At the 30th day B group, C group of adhesion degree aggravated, but had not enterorrhagia, obstruction and perforation. granule abscission rate and the adhesion rat with periphery small intestine and the obstruction rate of C group obviously was lower than B group (P<0.05).Under the light microscope observed: At the 14th and 30th day, A group small intestine only light phlegmonosis. At the 14th day, intestinal gland thinning and pack bloom defluxion for be apart from plan target area 0.5cm. The tips of bloom defluxion and interstitial edema relieved for be apart from plan target area 0.5cm. There was no glandular organ construction change for be apart from plan target area 1.0cm. There was mainly regeneration and reparation at the 30th day. At the 14th day C group bloom to line up in order , interstitial edema relieve, and no manifest demarcation of colic omentum and tunica serosa intestini tenuis, multiplicity inflammatory cell infiltrate for be apart from plan target area 0.2cm. inflammatory cell infiltrate palliate for be apart from plan target area 0.5cm. At the 30th day collagenoblast proliferation on the place of colic omentum pkg particle, inflammatory cell infiltrate aggravation. At the 14th and 30th day B group compared with A group, B group compared with C group, had statistics significance in being apart from plan target area 0.2 cm,0.5cm (P<0.05), had no statistics significance in being apart from plan target area 1.0cm (P>0.05).Conclusions: The 120Gy iodine-125 seeds may have the radioactivity damage to the rabbit small intestine, the damage gradually relieve to follow the increase of target area's distance, and gradually reparation to follow the lasting of time; the colic omentum which thickness 1.0cm interface wraps the seeds to prevent of small intestine effectively. |
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