Relationship of actual absorbed dose and volumetric change in patients with squamous cell carcinoma of thyroid treated by 125I radioactive seeds / 中华内分泌外科杂志

ABSTRACT

Objective:To investigate the relationship between dosimetric parameters and tumor volume change after 125I implantation for thyroid cancer and obtain better dosimetric parameters that predict the curative effect more accurately. Methods:A total of 22 consecutive patients with thyroid cancer (23 targets) who received 125I interstitial brachytherapy in Department of Oncology, Hebei General Hospital were retrospectively analyzed. All the patients received post-operative dose verification, and the D 90 (Minimum dose received by 90% target volume) was calculated. After a regular follow-up, the tumor volume reduction ratio after t months (R t) , actual absorbed dose (D 1m) , efficacy corrected absorbed dose (D 1e) , and sensitivity corrected absorbed dose (D 1s) of the first month were calculated according to the actual follow-up CT images. The statistical test was carried out by SPSS21.0. The Spearman linear analysis was applied to analyze the relationship between D 90, D 1m, D 1e, D 1s and R t, and the curve fitting was also completed. Results:The post-operative D 90, D 1m, D 1e, D 1s and R t were (129.73±14.22) Gy, (36.95±7.35) Gy, (43.45±11.32) Gy, (41.78±13.39) Gy, and (32.00±19.00) %, respectively. And the correlation coefficient were 0.692, 0.551, 0.728, and 0.858, respectively, which showed significant positive relevance between dosimetric parameters and tumor volume change ( P<0.01) , the curve fitting presented cubic function. Conclusion:The post-operative D 90, D 1m, D 1e, and D 1s can be predictors for curative effect, and D 1s is the best predictor.