18F-fluoride-PET for dynamic in vivo monitoring of bone formation in multiple myeloma

Abstract

Background: Bone disease in multiple myeloma is characterized by reduced bone formation. The gold standard of bone formation is the mineral apposition rate (MAR), an invasive technique reflecting bone formation at a single site. We compared 18F-fluoride-PET with the MAR in myeloma patients. Methods: Bone formation was measured before and after bortezomib treatment by determination of the MAR in iliac bone marrow biopsies and the measurement of 18F-uptake. Results: The inter- and intra-individual variations in 18F-uptake (SUVA50%) were pronounced as 33.50 (range 4.42 to 37.92) and 27.18 (range 4.00 to 31.18), respectively. A significant correlation between the MAR and 18F-uptake was found (r = 0.80, p = 0.017). There was a heterogeneous response after treatment varying from −2.20 to 4.53. Conclusions: Iliac 18F-uptake was associated with the local MAR in myeloma patients. Furthermore, 18F-fluoride-PET demonstrated the heterogeneity of in vivo bone formation, enabling monitoring during treatment.