The Clinical Research Of Prediction And Risk Factor Of Radiation Induced Lung Injury

Objective Part one:to investigate if [¹⁸F]2-fluoro-2-deoxyglucose (FDG) uptakechanges in the lung after radiotherapy can be used as a new predictor for acuteradiation pneumonitis.Part two:the purpose of this study was to investigate if thediabetics are more vulnerable to radiation induced pulmonary damage.Part three:toinvestigate the effect of diabetes mellitus on radiation induced lung injury.Methods Part one:Forty-one patients with lung cancer underwent FDG positronemission tomography/computed tomography (FDG-PET/CT) imaging before andafter radiotherapy.The mean standardized uptake value (SUV) were measured for theisodose regions of 0～10Gy,10～20Gy,20～30Gy,30～40Gy,40～50Gy.The mean SUVof these regions after radiotherapy were compared with baseline.The range of themean SUV in patients developed from radiation pneumonitis (RP) was also comparedto those who did not.The statistic difference was determined by matched pair t-test.Radiation Therapy Oncology Group (RTOG) Criteria was used for diagnosis andgrading of RP.Part two:52 diabetics with non small cell lung cancer were selectedand 104 non small cell lung cancer patients without diabetes mellitus were registeredin control group.All the patients have undergone three-dimension conformalradiation therapy between January 2006 and March 2007.A follow-up study wasperformed.Radiation pneumonitis was diagnosed according to the criteria ofRadiation Therapy Oncology Group.The statistical difference was determined bychi-square test.Part three:sixty Wistar mice were randomized into three groups(group A,B and C).Type 2 diabetes mellitus mice models were established byintraperitoneal injection (STZ 50mg/Kg) in treatment groups (Group A).Meanwhilethe control groups (group B and group C)were injected intraperitoneally with normalsodium.The group A and B received a single dose 15Gy to the right lung.The otherparts of the mouse were all shielded by 8cm lead blocks.Group C received 0Gy to theright lung.Six weeks later all mice underwent CT scan and the findings werecompared.Morphological changes of the lung tissue were observed under light.Results result of part one:with a median follow-up of 12 months,eleven of 41patients (26.8%) have developed grade 2 and above acute radiation pneumonitis.Themean SUV of regions (10～20Gy,20～30Gy,30～40Gy,40～50Gy) increased afterradiation therapy in all 41 patients,these patients had significantly higher FDGactivity in regions reveived 10Gy or more(P＜0.001).Compared to their counterparts,the elevation was significantly greater in those patients who developed acute RP subsequently.Result of part two:Twenty-one of 52 (40.38%) patients with diabeteswere diagnosed as radiation pneumonitis (grade 2 or greater).In the control group theratio was 21.35 %(22/104).The morbidity of the radiation pneumonitis in patientswith diabetes mellitus is higher than those without diabetes mellitus (40.38% vs.21.35%,P＜0.05).The value of the relative risk is 2.05.The confidence interval is(1.17,3.58).Result of part three:The detection rate of the radiation induced lunginjury of the Group A was higher than the group B (62.5% vs 30%),P＜0.05).Conclusion The mean SUV of the lung tissue may be a useful predictor for theacute RP.FDG-PET/CT may play a new role in study of the radiation damage oflung.