Application of F-18-Sodium Fluoride (NaF) dynamic PET-CT (dPET-CT) for defect healing: Comparison of biomaterials in an experimental osteoporotic rat model

Objectives The aim of the current study was to measure and compare the effect of different biomaterials for the healing of osteoporotic bone defects in the rat femur using 18F-Sodium Fluoride dPET-CT.

Methods Osteoporosis was induced by ovariectomy and a calcium restricted diet. After three months, rats were operated to create a 4 mm defect in the distal metaphyseal femur with internal fixation. Different biomaterials including calcium phosphate cement CPC-based (Group II), silicate/collagen-based (Group III) and iron-based (Group IV) materials have then been used for bone replacement and defect healing. Furthermore, a control group of 22 rats without any biomaterial (Group I) was used for reference. 18 weeks after osteoporosis induction and 6 weeks following femoral surgery, dPET-CT studies scan were performed with 18F-Sodium Fluoride. SUVs and a 2-tissue compartmental learning-machine model (K1-k4, VB, influx) were used for quantitative analysis.

Results K1 was the most significant parameter for the characterization of healing process and revealed the best differentiation between the control group (Group I) and the CPC-based group (Group II). VB was the most significant parameter for the characterization between Group I and Group III, and k3 for the characterization between Group I and Group IV based on Wilcoxon rank-sum test (p<0.05).

Conclusions PET scanning using 18F-Sodium Fluoride seems to be a sensitive and useful method for evaluation of bone healing after replacement with these biomaterials.