Comparison of 18F-fluoride PET/CT, 18F-FDG PET/CT and bone scintigraphy (planar and SPECT) in detection of bone metastases of differentiated thyroid cancer: a pilot study

Objective: We compared the efficacies of F-18-fluoride positron emission tomography (F-18-fluoride PET)/CT, F-18-fludeoxyglucose PET (F-18-FDG PET)/CT, and Tc-99m bone scintigraphy [planar and single photon emission CT (SPECT)] for the detection of bone metastases in patients with differentiated thyroid carcinoma (DTC). Methods: We examined 11 patients (8 females and 3 males; mean age +/- standard deviation, 61.9 +/- 8.7 years) with DTC who had been Suspected of having bone metastases after total thyroidectomy and were hospitalized to be given I-131 therapy. Bone metastases were verified either when positive findings were obtained on both I-131 scintigraphy and CT or when MRI findings were positive if MRI was performed. Results: Metastases were confirmed in 24 (13,6%) of 176 bone segments in 9 (81.8%) of the 11 patients. The sensitivities of F-18-fluoride PET/CT and Tc-99m bone scintigraphy (SPECT) were significantly higher than those of F-18-FDG PET/CT and Tc-99m bone scintigraphy (planar) (p < 0.05). The accuracies of F-18-fluoride PET/CT and Tc-99m bone scintigraphy (SPECT) were significantly higher than that of Tc-99m bone scintigraphy (planar) (p < 0.05). Conclusion: The sensitivity and accuracy of F-18-fluoride PET/CT for the detection of bone metastases of DTC are significantly higher than those of Tc-99m bone scintigraphy (planar). However, the sensitivity and accuracy of Tc-99m bone scintigraphy (planar) are improved near to those of F-18-fluoride PET/CT when SPECT is added to a planar scan. The sensitivity of F-18-FDG PET/CT is significantly lower than that of F-18-fluoride PET/CT or Tc-99m bone scintigraphy (SPECT). Advances in knowledge: This article has demonstrated first the high efficacy of F-18-fluoride PET/CT for the detection of bone metastases of DTC.