The Radioprotection Of Salivary Glands By Vitamin C And Amifostine In ¹³¹I Treatment Of Patients With DTC

Purpose:To investigate salivary gland radioprotection of Amifostine and vitamin C in Radioiodine Treatment（RIT）of patients with differentiated thyroid cancer（DTC）by quantitative assessment of salivary gland scintigraphy,meanwhile,observing the influence of amifostine in the ablation of residual thyroid tissue by ¹³¹I remedial whole body scan（Rx-WBS）and neck SPECT/CT examination in RIT.Methods:63 patients who suffer from DTC and total thyroidectomy with an age of 20-67 years,were divided into two groups.Vitamin C group 32 patients who were treated with vitamin C tablets,100mg/2h,600-800mg/d,mouth meltingly in 2h after RIT,for 7days.Combination group of vitamin C and amifostine 31 patients who were treated with amifostine 400 mg intravenously before RIT and vitamin C tablets in 2h after RIT,methods ibid.Dynamic Salivary scintigraphy was performed with 99 m Tc-pertechnetate one day before radioiodine treatment（RIT）and six months after RIT,salivary gland function was quantitatively evaluated by parameters UR20,EF,EP and ER;xerostomia was graded according to World Health Organization（WHO）criteria,to evaluate the protective effects of the two methods.The effects of amifostine on the ablation of residual thyroid tissue of RIT was evaluated by ¹³¹I Rx-WBS and cervical SPECT / CT examination at 5-7 days after RIT.Results:1.Compared with those before treatment,six months after RIT,the parotid gland function parameters UR20 and EF in vitamin C group decreased by 0.02%（-0.06 0.07%）,-0.80%（-8.38 5.05%）,respectively,the difference was not statistically significant（P> 0.05）,the EP prolonged 0.65（0.10 2.25）min,the ER decreased by 4.10%（0.03 14.33%）,the difference was statistically significant（P <0.05）.Compared with those before treatment,the submandibular glands function parameters UR20 and EF in vitamin C group decreased by-0.01%（-0.05⁰.03%）、1.40%（-10.38¹3.95%）,respectively,the difference was not statistically significant（P> 0.05）,the EP prolonged 1.4（0.80².63）min,the ER decreased by 11.45%（5.38²0.98%）,the difference was statistically significant（P <0.05）,indicating that vitamin C has a protective effect on the uptake function of salivary glands,but it has a limited protective effect on the secretion function of salivary glands in chronic injury.2.Compared with those before treatment,six months after RIT,the function parameters UR20,EF,EP and ER of parotid gland and submandibular gland in the combination group of Vitamin C and amifostine had no significant changes（P> 0.05）.3.There was no significant difference in the functional parameters ΔUR20 and ΔEF of parotid glands and submandibular glands between the two groups（P> 0.05）,but compared with the combination group,the parotid glands and submandibular glands of vitamin C group has a longer ΔEP and a lower ΔER,respectively,and the difference had statistical significance（P<0.05）.4.The success rates of the vitamin C group and combination group were 70.00% and 78.95%,respectively,there was no significant difference between the two groups（P = 0.716）,showing that there was no significant difference in the the success rates of ablation of residual thyroid tissue in RIT in both groups.Conclusion:Vitamin C has a protective effect on uptake function of salivary gland of patients who were treated with high dose ¹³¹I,but it is less effective on secretion function of salivary glands in chronic injury.Amifostine combined with vitamin C has a better protective effect on the secretion function of salivary gland in the chronic injury.In addition,we found that amifostine had no obvious effect on the ablation of residual thyroid tissue in RIT.