Research Of Evaluation For Radiation-induced Lung Injury And Therapeutic Effect Of Early Medicine Based On320-slice CT Perfusion Image

This subject consisted of two parts: Part One, established CT perfusion (CTP)imaging assessment indicators for radiation lung injury (RILI) models of rabbits anddiscussed the implications of CTP parameters through the hemodynamic changes ofRILI. Part Two, utilized perfusion imaging indicators to assess the therapeutic valueof early drug intervention.Part One：To establish RILI-Animal Model and assessment indicators of320-slice CTP perfusion and discuss the implications of CTP parameters throughthe hemodynamic changes of RILI.Objective To establish a method for early detecting radiation lung injury anddiscuss the relationship between the method and hemodynamic changes.Methods During the procedure, sixty adult New Zealand rabbits wererandomly divided into six groups, which involved one control group and five studygroups. The right lung of rabbits in the study groups were radiated with dose of30Gyby Varian medical linear accelerator in one fraction. Then, The320-slice CTP andpathological test following execution were performed at5time points involving thefirst day, the first week, the second week, the third week, and the eighth weekfollowing treatment, respectively. Morphological changes of lung tissues, alveolar,alveolar wall as well as dynamic changes of BF, PS and BV between control groupand study groups were observed.Result Rabbits in the study groups showed obvious changes of lung injury asthe duration elongated following radiation. Meanwhile, BF and BV significantlydecreased, and PS sharply increased. Pathological sections in the study groups showedchanges involving agglutination of leukocytes in the alveolar and pulmonaryinterstitium, damage of alveolus structures, broadening interstitium, severe hemorrhage, edema, and finally fibrotic.Conclusion (1) New Zealand rabbits are used as samples in this experiment toestablish an animal-based RILI model successfully, which can obtain satisfactory CTPparameters and images;(2) Perfusion parameters of CTP involving BF, PS and BVcould demonstrate hemodynamic changes in lung tissues following radiation.Part Two: The therapeutic efficacy of early-stage drug treatmentevaluated by perfusion CT.Objective To identify RILI early by CTP and evaluate therapeutic effect afterperforming early intervention using dexamethasone.Methods During the procedure, sixty adult New Zealand long-eared rabbits wereused to establish a RILI animal-based experimental models and randomly divided intosix groups, which involved one control group and remaining five study groups..Dexamethasone was injected into the rabbit auricular vein (dosage:3mg/Kg) at oneday following positive result of the RILI perfusion images in the study group, andthen, repeated one time per day for a week. Then, The320-slice CTP were performedfor one group selected randomly at the first week, the second week, the third week,and the eighth week following radiation, respectively. Dynamic changes of BF, PSand BV between control group and study groups were observed.Result Obvious changes of lung injury were showed at5time points involving1d,1w,2w,3w and8w following inflammation in control group and dexamethasoneintervention group. Meanwhile, BF, BV were significantly lower, and PS wasincreased. The values of BF and BV in study group at each time point were higherthan those in control group. The value of PS in study group at each time point waslower than that in control group. The differences of above results all reached statisticalsignificance (P＜0.05).Conclusion Dexamethasone treatment can reduce the permeability of the lung tissueand the degree of radiation-induced lung injury. CTP can be used to evaluate acuteRILI early and guide treatment.