Comparison of¹⁸F-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 ¹⁸F-fluoride positron emission tomography (¹⁸F-fluoride PET)/CT, ¹⁸F- fludeoxyglucose PET (¹⁸F-FDG PET)/CT, and ^99mTc 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 ¹³¹I therapy. Bone metastases were verified either when positive findings were obtained on both ¹³¹I 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 ¹⁸F-fluoride PET/CT and ^99mTc bone scintigraphy (SPECT) were significantly higher than those of ¹⁸F-FDG PET/CT and ^99mTc bone scintigraphy (planar) (p , 0.05). The accuracies of ¹⁸F- fluoride PET/CT and ^99mTc bone scintigraphy (SPECT) were significantly higher than that of ^99mTc bone scintigraphy (planar) ( p < 0.05). Conclusion: The sensitivity and accuracy of ¹⁸F-fluoride PET/CT for the detection of bone metastases of DTC are significantly higher than those of ^99mTc bone scintigraphy (planar). However, the sensitivity and accuracy of ^99mTc bone scintigraphy (planar) are improved near to those of ¹⁸F-fluoride PET/CT when SPECT is added to a planar scan. The sensitivity of ¹⁸F-FDG PET/CT is significantly lower than that of ¹⁸F-fluoride PET/CT or ^99mTc bone scintigraphy (SPECT). Advances in knowledge: This article has demonstrated first the high efficacy of ¹⁸F-fluoride PET/CT for the detection of bone metastases of DTC.