The Study On The Consistency Of STg And ¹³¹I Whole Body Scan,and Relationship Between STg And The Factors Related To Absorbed Dose Of Residual Thyroid Tissue Of First ¹³¹I Remnant Ablation In Adults With DTC

Objective:This was a study on the consistency of sTg and ¹³¹I whole body scan,and relationship between sTg and the factors related to absorbed dose of residual thyroid tissue of first¹³¹I remnant ablation in adults with DTC.Methods:A retrospective study with 34 cases of adult patients with DTC(male 8 cases,female 26 cases,age?47.9±12.9?]who underwent first ¹³¹I remnant ablation in the department of nuclear medicine,the first hospital of China Medical University from May2017 to April 2018 was analyzed with complete patient data and no distant metastasis.All the patients had post-treatment whole body scan?Rx–WBS?.6 to 18 months after ¹³¹I remnant ablation,the patients withdrawal of L-T₄ for at least 2 weeks and thyroid stimulating hormone?TSH?level reached to 30 mU/L,sTg level and Dx-WBS were then evaluated.According to 2014 edition of the domestic ¹³¹I treatment of differentiated thyroid cancer guidelines,patients are divided into groups as group A?serum sTg negative?,group B?serum sTg positive?,group C?Dx-WBS negative?,group D?Dx-WBS positive?to analyze the consistency of sTg and Dx-WBS for remnant ablation efficacy evaluation.According to sTg together with Dx-WBS patients are divided into groups as group 1?serum sTg negative and Dx-WBS negative?,group 2?serum sTg negative and Dx-WBS positive?,group 3?serum sTg positive and Dx-WBS negative?and group 4?serum sTg positive and Dx-WBS positive?to analyze the consistency of sTg and Dx-WBS for remnant ablation efficacy evaluation.The consistency between sTg and Dx-WBS in evaluating the efficacy of remnant ablation was investigated.Based on the¹³¹I radioactive distribution characteristics of residual gland on Rx-WBS,the radioactive activity and mass of residual gland were measured and calculated,and the relationship between sTg level,residual gland activity,residual gland mass and clinical factors was analyzed.SPSS 22.0 was used for chi-square test or Fisher's exact probability test,t test,rank sum test and correlation analysis.p<0.05 was considered as significant difference.Results:1.34 first ¹³¹I DTC remnant ablation adults patients with pathological diagnosis of papillary thyroid carcinoma?PTC?,including 8 men,26 women with average age?47.9±12.7?were selected.The efficacy of remnant ablation valuated by serum sTg was67.6%?23/34?,while that of Dx-WBS was 97.1%?33/34?.There was statistically significant difference in the efficacy of remnant ablation between sTg and Dx-WBS[p<0.05?0.003?].In group C,66.7%?22/33?sTg were negative,and 33.3%?11/33?sTg were positive.In group D,100%?1/1?were serum sTg negative,and 0%?0/1?were serum sTg positive.Dx-WBS negative patients accounted for 96.7%?22/23?and Dx-WBS positive patients accounted for 4.3%?1/23?in group A.Negative Dx-WBS in group B accounted for 100%?11/11?,and positive Dx-WBS in group B accounted for 0%?0/11?.The proportion of group 1 was 64.7%?22/34?;group 2 for 2.9%?1/34?;group 3 for 32.4%?11/34?and group 4 for 0%?0/34?.2.The residual gland activity in the group A and group B was 4.05?1.53,13.46?MBq and 8.04?3.64,14.41?MBq,respectively,the difference was not statistically significant?z=-1.419,p=0.136?,and there was no correlation between serum sTg and residual gland activity?r=0.199,p=0.259?.The mass of residual glands in group A and group B were?3.90±1.88?g and?3.66±1.10?g,respectively,and the difference was not statistically significant?t=0.399,p=0.693?.There was no correlation between serum sTg and the mass of residual glands?r=0.084,p=0.639?.There was no correlation between serum sTg and TgAb?r=0.084,p=0.639?.There was no significant correlation between residual gland activity and treatment dose?r=-0.320,p=0.065?.3.The age of group A and group B were?49.5±11.5?years old and?43.1±14.3?years old,respectively.There was no significant difference between the two groups in age?t=1.406,p=0.169?.There was no significant difference in gender between the two groups?p=0.388?.The TSH levels?after withdrawal of L-T₄?of the two groups were?70.23±24.30?mU/L and?80.70±19.20?mU/L,respectively.There was no significant difference between the two groups?t=-1.246,p=0.222?.The TgAb levels of the two groups were 2.25?1.40,6.59?U/ml and 1.93?1.36,2.45?U/ml,respectively,and the difference was not statistically significant?z=-1.031,p=0.303?.The therapeutic doses of the two groups were?79.3±20.9?mCi and?84.1±20.2?mCi,respectively,and the difference was not statistically significant?t=-0.626,p=0.536?.Conclusions:1.STg and Dx-WBS were inconsistent in the efficacy evaluation of¹³¹I remnant ablation;2.There was no correlation between sTg level and residual gland activity 2 or 3 daysafter remnant ablation and residual gland mass after treatment.There was no correlation between residual gland activity 2 or 3 days after remnant ablation and treatment dose.3.There was no correlation between serum sTg and patients'age,gender,post-treatment TSH and TgAb?after withdrawal of L-T₄?,and treatment dose.