%0 Journal Article %A Shinji Ito %A Katsuhiko Kato %A Mitsuru Ikeda %A Shingo Iwano %A Naoki Makino %A Masanori Tadokoro %A Shinji Abe %A Satoshi Nakano %A Masanari Nishino %A Takeo Ishigaki %A Shinji Naganawa %T Comparison of 18F-FDG PET and Bone Scintigraphy in Detection of Bone Metastases of Thyroid Cancer %D 2007 %R 10.2967/jnumed.106.039479 %J Journal of Nuclear Medicine %P 889-895 %V 48 %N 6 %X We compared the efficacies of 18F-FDG PET and 99mTc-bone scintigraphy for the detection of bone metastases in patients with differentiated thyroid carcinoma (DTC). Methods: We examined 47 patients (32 women, 15 men; mean age ± SD, 57.0 ± 10.7 y) with DTC who had undergone total thyroidectomy and were hospitalized to be given 131I therapy. All patients underwent both whole-body 18F-FDG PET and 99mTc-bone scintigraphy. The skeletal system was classified into 11 anatomic segments and assessed for the presence of bone metastases. Bone metastases were verified either when positive findings were obtained on >2 imaging modalities—201Tl scintigraphy, 131I scintigraphy, and CT—or when MRI findings were positive if vertebral MRI was performed. Results: Bone metastases were confirmed in 59 of 517 (11%) segments in 18 (38%) of the 47 study patients. The sensitivities (visualization rate) for bone metastases on a segment basis using 18F-FDG PET and 99mTc-bone scintigraphy were 50 of 59 (84.7%) and 46 of 59 (78.0%), respectively; the difference between these values was not statistically significant. There were only 2 (0.4%) false-positive cases in a total of 451 bone segments without bone metastases when examined by 18F-FDG PET, whereas 39 (8.6%) were false-positive when examined by 99mTc-bone scintigraphy. Therefore, the specificities of 18F-FDG PET and 99mTc-bone scintigraphy were 449 of 451 (99.6%) and 412 of 451 (91.4%), respectively; the difference between these values was statistically significant (P < 0.001). The overall accuracies of 18F-FDG PET and 99mTc-bone scintigraphy were 499 of 510 (97.8%) and 458 of 510 (89.8%), respectively; the difference between these was also statistically significant (P < 0.001). Conclusion: The specificity and the overall accuracy of 18F-FDG PET for the diagnosis of bone metastases in patients with DTC are higher than those of 99mTc-bone scintigraphy, whereas the difference in the sensitivities of both modalities is not statistically significant. In comparison with 99mTc-bone scintigraphy, 18F-FDG PET is superior because of its lower incidence of false-positive results in the detection of bone metastases of DTC. %U https://jnm.snmjournals.org/content/jnumed/48/6/889.full.pdf