| Objective Firstly to investigate the influence of the diameter of needle, the volume of VX2 cell suspension and the modality of VX2 cell in making the rabbit model under CT guidance in order to find the best way in establishing animal model. Secondly to evaluate the therapeutic effect of 125I seeds upon the rabbit VX2 liver tumor and to provide experimental basis for clinical application of 125I seeds implantation.Methods The experiment was divided into two parts. Part I:Thirty-two healthy New Zealand white rabbits divided into 4 groups at random(8 per group) were implanted by using different needles, tumor cell suspension of different volumes and different tumor modalities. In Group A and Group B, the VX2 cell suspension was injected in a volume of 0.1ml with the 25-gauge and the 22-gauge needles respectively. In Group C, VX2 cell suspension was injected in a volume of 0.5ml with the 25-gauge needle. Two fragments of VX2 tumor were implanted with the 18-gauge needle in Goup D. There were 107 tumor cells in each millilitre of suspension and the fragment was 1mm3 in volume. All the rabbits underwent US and CT at 1st,2nd,3rd and 4th week after operation in order to observe the success rate of implantation, the index of tumor growth, the complication and survival time. Two rabbits with solitary liver tumor that was about 2cm in diameter at 2nd or 3rd week were chosen from each group for the second part of the experiment. All the rabbits were dissected after death for pathological observation. PartⅡ:Eight chosen rabbits were randomly divided into control group (n=2) and treatment group(n=6).125I seeds and empty seeds were implanted in treatment group and control group respectively. CT examination and liver function test were performed before operation and at 1 st week,2nd week,1 st month,2nd month after operation. All the rabbits were dissected two months after operation for pathological observation, and therapeutic effect of 125I seeds on rabbit implanted liver tumor was evaluated according to pathological results.Result 1. There was no significant difference in success rate between every two groups and between suspension group and fragments group. The incidence of complication in group A was lower than that in Group B and Group C, there was a significant difference in the incidence of ectopic implantation in abdominal wall between Gorup A and Group B and between Group A and Group C. The incidence of complication in fragments group was lower than that in suspension group. There was a significant difference in the incidence of ectopic implantation in abdominal wall between suspension group and fragments group. The survival time in Group A was longer than that in Group B and Group C. And there was no significant difference in survival time between suspension group and fragments group.2. There was a significant difference in the decrease of tumor size between treatment group and control group. The decrease of tumor size in trearment group had a significant difference before and after implantation of 125I seeds.Conclusion 1. The diameter of needle, the volume of VX2 cell suspension and the modality of tumor influence the quality of the rabbit model with VX2 liver tumor. Utilization of the needle with a smaller diameter and less volume of suspension leads to an remarkable decrease in the implantation in abdominal cavity, and the implantation in abdominal wall significantly decreases by using fragments of tumor. CT Guided 125I seeds interstitial implantation was a safe, effective method in treating rabbit VX2 liver tumor. The prescribed dose of 120Gy had a good curative effect. |
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