PT - JOURNAL ARTICLE AU - Stefano Panareo AU - Roberta Rossi AU - Corrado Cittanti AU - Melchiore Giganti AU - Napoleone Prandini AU - Paola Franceschetti AU - Vincenzo De Biasi AU - Silvia Lunardon AU - Luciano Feggi TI - Recombinant thyrotropin stimulation improves 18F-FDG PET/CT sensitivity in patients with recurrent differentiated thyroid cancer DP - 2011 May 01 TA - Journal of Nuclear Medicine PG - 1308--1308 VI - 52 IP - supplement 1 4099 - http://jnm.snmjournals.org/content/52/supplement_1/1308.short 4100 - http://jnm.snmjournals.org/content/52/supplement_1/1308.full SO - J Nucl Med2011 May 01; 52 AB - 1308 Objectives To evaluate if the stimulation with Recombinant Thyrotropin (Rh-TSH) would improve the sensitivity of 18F-FDG PET/CT (PET) in patients with Differentiated Thyroid Cancer (DTC) in progression with high Thyreoglobulin (Tg) levels and both negative 131I Total Body Scintigraphy (TBS) and PET performed 6 months earlier. Methods We studied 10 patients with DTC in progression and both negative 131I TBS and PET performed 6 month earlier. All patients went pre-treated with Rh-TSH before PET. Tg and TSH levels were evaluated before and 24-48 hours after the injection of Rh-TSH. PET was performed using a dedicated PET-CT tomograph. Results Tg levels after Rh-TSH were within 2.1 and 27.6 ng/ml and they were unchanged in all patients compared to 6 months before. PET with Rh-TSH and Tg levels from 6.4 to 27.6 ng/ml was positive in 6 cases (mean SUV max 4.9) showing a direct correlation between Tg level and FDG uptake (p<0.1). Of these 3 showed right paratracheal radiotracer uptake not observed on UltraSonography (US) ad Computed Tomography. Three cases showed a laterocervical FDG uptake confirmed by US. All PET findings were confirmed by histological analysis after lymphadenectomy. Two patients with Tg levels respectively of 3.4 and 3 ng/ml showed no tracer uptake on PET and they were followed. Two patients with negative PET and Tg levels respectively of 8 and 11.7 ng/ml were re-treated with 131I because of the US localization of loco-regional disease recurrence. Conclusions PET seems to be better then conventional diagnostic image for the localization of lymph node recurrence of DTC in progression after Rh-TSH stimulation showing a direct correlation between Tg level and SUV max. Our results suggest that the Rh-TSH stimulation can improve the diagnostic sensitivity of PET in patients with DTC in progression changing their therapeutic strategy and follow-up. Our data must be confirmed in a larger casuistry