[en] Objective: To investigate the practical value of dynamic bone imaging with ^99mTc-MDP in quantitatively evaluating the vascularization and ossification effects during the repairing of bone defect with the tissue-engineered bone graft. Methods: 15 model rabbits of skull defect were built which were symmetrically implanted nano-hydroxyapatite/collagen-l-type (nHAC) and particle-hydroxyapatite/collagen-l-type (pHAC) respectively into the defect sites. They were randomly and averagely divided into 5 time-point groups, namely 2, 4, 8, 10 and 12 week groups. After intravenous injection of ^99mTe-MDP via the auricle vein, the routinely dynamic bone imaging was performed. Using the ROI technique, the radioactivity peak and uptake ratio were calculated. The parameters mentioned obove were compared between the nHAC and pHAC. The X-ray of skull was done and the images were observed. Results: (1) Dynamic bone imaging: at every time-point, the radioactivity peak of perfusion phase and uptake ratio of static phase in nHAC implanted area both were significantly higher than those in pHAC implanted area (P<0.01). With the implantation time extending, the radioactivity peak of perfusion phase and uptake ratio of static phase in nHAC and pHAC implanted areas both increased; and these parameters after 8 week were significantly higher than those at 2 week in nHAC implanted area (P<0.05), while after 10 weeks in pHAC implanted area (P<0.01). (2) X-ray imaging: The bone repairing of nHAC was earlier than pHAC, and the density of neo-bone in nHAC was also greater than that in pHAC. Both edge and center of implanted area presented neo-born in nHAC, but only edge in pHAC. Conclusions: In promoting early vascularization and accelerating ossification, the nHAC has obvious superiority to the pHAC. The dynamic bone imaging with ^99mTc-MDP may evaluate the vascularization and ossification effects accurately, dynamically and quantitatively during the repairing of bone defect with the tissue-engineered bone graft. (authors)