The detective value of 131I SPECT/CT on the recurrence and metastasis of well-differentiated thyroid cancer.

Objective To investigate the detective value of 131I SPECT/CT scan and 131I whole body scans on the recurrence and metastasis of well-differentiated thyroid cancer(DTC). Methods There were 197 patients who had been diagnosed as DTC between 2001 and 2007, and their 197 131I SPECT/CT scans and 131I whole body scans were retrospectively reviewed. According to the concentration,location,size,and range of radioactive uptake in the 131 I images,DTC were divided into stage Ⅰ-only thyroid beds were involved;stage Ⅱ-thyroid beds and neck lymph nodes or thyroid beds and mediastinal lymph nodes were involved;stage Ⅲ-neck lymph nodes or mediastinal lymph nodes were involved and lung were involved;stage Ⅳ-neck lymph nodes,mediastinal lymph nodes and lung were involved,or neck lymph nodes,mediastinal lymph nodes,bone and some other organs were involved. The radioactive uptaking grades were divided into four levels(0,1,2,3)in accordance to the distribution and concentration of the radioactive uptake. Results The difference in staging scores and radioactive uptake grading of vervical mediastinum and bone lesions between the results of 131I whole body scans and 131I SPECT/CT were significantly (Z=-3.864,P =0.000;Z =-3.779,P =0.000;Z =-3.434,P =0.001),and there were no significant differences in the radioactive uptake grading of situ and lung lesions between these two imaging methods(Z =-1.507,P =0.13;Z =-0.839,P =0.401). Conclusion The detecting value of 131I SPECT / CT scan is superior to that of 131I whole body scan in metastasis and recurrence of DTCs.