99mTc-MDP动态骨显像在定量监测组织工程骨修复兔颅骨缺损中的应用

目的 探讨99^mTc-MDP动态骨显像在定量监测组织工程骨修复骨缺损过程中血管化和成骨效果中的应用价值.方法 选取兔15只,制作颅骨缺损模型缺损处对称植入纳米羟基磷灰石/Ⅰ型胶原复合人工骨（nHAc）和颗粒羟基磷灰石/Ⅰ型胶原复合人工骨（pHAc）],随机分为2、4、8、10和12周5组,每组3只.耳缘静脉注射99^mTc-MDP后,行常规骨动态显像,利用ROI技术,计算出放射性峰值和摄取比值.比较nHAc和pHAC植入区各时相的放射性峰值或摄取比值.行头颅X线摄片,并观察分析图像.结果 ①骨动态显像：nHAC组植入区各时间点的血流相放射性峰值及静态相摄取比值均显著高于pHAc组（P＜0.01）;随时间延长,nHAc及pHAc组植入区的血流相放射性峰值与静态相摄取比值均逐渐增高;nHAc组上述参数于第8周开始显著高于第2周（P＜0.05）,而pHAc则始于第10周（P＜0.01）.②X射线检查：nHAc组骨修复时间早于pHAc组,且前者各时间点的新生骨密度均更高;nHAC组植入区边缘及中央区均见新骨形成,而pHAC组仅限于边缘部位.结论 在促进早期血管化及加速成骨活动方面,nHAc明显优于pHAc.99^mTc-MDP动态骨显像能准确、定量、动态地评价组织工程骨修复骨缺损中血管化和成骨效果.

Using dynamic bone imaging with 99mTc-MDP for quantitatively evaluating the repairing of skull defect with tissue-engineered bone graft in rabbits

Objective To investigate the practical value of dynamic bone imaging with ~ 99m Tc -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-1-type (nHAC) and particle-hydroxyapatite/collagen-1-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 ~ 99m Tc -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 ~ 99m Tc -MDP may evaluate the vascularization and ossification effects accurately, dynamically and quantitatively during the repairing of bone defect with the tissue-engineered bone graft.;