Application Of CT Value Of Post-ball Adipose Tissue And Clinical Study Of LOF In Moderate To Severe Active TAO Retro-orbital Irradiation

Part 1 Application of CT value of post-ball adipose tissue in diagnosis of TAO Objective:To explore the value of CT value of post-ball adipose tissue in diagnosis of moderate to severe active TAO.Methods:From 2012 to 2017,58 cases of moderate to severe active TAO patients undergoing radiotherapy in our department were selected as TAO group,and another 58 cases of tumor patients without eye disease were selected as normal group.The t-test of independent samples was used to compare the CT value of post-ball adipose tissue,exophthalmols,and eyesight of the two groups.Pearson correlation analysis was performed to analyze the relationship between the CT value of post-ball adipose tissue,exophthalmols,and CAS scores of TAO group.Results:The CT value of post-ball adipose tissue and exophthalmols in both eyes of TAO group were greater than that of the normal group(P=0.000),and the eyesight was smaller than that of the normal group(P=0.000).The CT value of post-ball adipose tissue in TAO group was positively correlated with CAS score and exophthalmols(P=0.000).Conclusion:The CT value of post-ball adipose tissue can be used as an objective and quantitative evaluation index for the diagnosis of TAO.Part 2 Clinical study of LOF technique in TAO retro-orbital irradiation and the application of CT value of post-ball adipose tissue in evaluating the radiotherapy effect of TAO Objective:To evaluate the dosimetric advantages of lateral opposing fields(LOF)compared to Intensity-Modulated Radiation Thearpy(IMRT)in the moderate-to-severe active TAO retro-orbital irradiation and the application of CT value of post-ball adipose tissue in evaluating the radiotherapy effect of TAO.Methods:58 TAO patients who underwent radiotherapy from 2012 to 2017 were chosen.LOF and IMRT plans were developed for each patient separately.The independent sample t-test was used to compare the difference between CI、HI、PTV and the dose of organs at risk(OAR)between two groups.Pearson correlation analysis was used to analyze the relationship between exophthalmols and the dose of OAR.Efficacy and side effects were evaluated 6 months after radiotherapy(LOF).Results:CI、HI in IMRT group were better than those in LOF group,but the dose of crystal,eyeball and optic nerve were higher than those in LOF group(P<0.05).There was no significant difference in D95(P=0.261).In LOF group,exophthalmols was positivelycorrelated with the dose of lacrimal gland(P=0.000),negatively correlated with the dose of crystal and eyeball(P=0.000),and no correlation between the dose of optic nerve(P>0.05).In IMRT group,there is no correlation above(P>0.05).Six months after radiotherapy of LOF group,the CT value of post-ball adipose tissue,exophthalmols and CAS score were lower than that before treatment(P=0.000),and eyesight was higher than that before treatment(P=0.000).△CT value of post-ball adipose tissue was positively correlated with △CAS score,△exophthalmols and△eyesight(P<0.05).In the LOF group,the median observation time was 16 months,10%(2/20)had dry eyes,and 5%(1/20)had decreased vision.Conclusion:LOF is safer than IMRT which can make full use of the high exophthalmols of TAO patients to reduce the dose of OAR.LOF technology can still be used as the standard irradiation technique for TAO radiotherapy.And the CT value of post-ball adipose tissue can be used as an objective and quantitative evaluation index for the radiotherapy efficacy evaluation of TAO.