| Objective To explore the feasibility of non-invasive detection of bone metabolism in vivo by utilizing the microPET/CT scanner, and to analyze the changes of bone metabolism in overiectomized rats.Methods Twelve 6-month non-pregnant female SD rats, weighting 290-310g, were randomly divided into two groups: ovariectomy ( OVX) group and sham-operation ( SHAM) group.Bone imaging of all the rats were performed using a dedicated small animal PET scan with 18 F-fluoride.The fluoride uptake value and BMD were quantified at the 4th lunbar vertebra, the left proximal femur, the femoral disphysis, the tibial midshafts, and the right tibia.After imaging, all the rats bled to dead through the abdominal aorta.The uterus was collected and weighed.The 4th lumar vertebra, the left proximal femur, the left femoral disphysis, and the tibial midshafts were collected and BMD of these parts was detected using DXA.The right tibia was obtained for the histomorphometric measurement.Results BMD of L4, the left proximal femur, the femoral disphysis, and the tibial midshafts in OVX group was significantly lower than that in SHAM group.Compared with that in SHAM group, the image intensity of L4, the left proximal femur, the femoral disphysis, and the tibial midshafts in microPET/CT in OVX group was significantly higher than that in SHAM group (P<0.05).And the intensity of bone ROI in OVX rats increased.No significant difference of the bone histomorphometric variables of the femoral disphysis between the two groups was observed.But the histomorphometric variables of the cancellous bone of the proximal femur were significantly different between the two groups.The PET image intensity of the left proximal femur, the femoral disphysis, and the tibial midshafts was negatively correlated with BMD.Conclusion MicroPET/CT is a useful non-invasive method to detect and quantify bone metabolism, which can provide a new method to diagnose osteoporosis. |