Early dynamic bone-imaging as an indicator of osseous blood flow and factors affecting the uptake of 99mTc hydroxymethylene diphosphonate in healing bone.

We determined the uptake of 99mTc-labeled hydroxymethylene diphosphonate in a surgically created defect in the canine tibia with early dynamic and delayed static bone scans. The defect consisted of a cortical bone window, ten by five millimeters, centered over the middle of the tibia. The dynamic bone scans consisted of sixty one-second images of the tibia, recorded immediately after the injections of 99mTc, and the static scans were single forty-five-minute uptake images of the tibia. These were performed and the dogs were killed at seven, fourteen, and twenty-eight days postoperatively. The dynamic scans detected the postoperative increase in tibial blood flow because the values calculated from these scans demonstrated a significant linear relationship to tibial blood flow determined with radioactive microspheres (r = 0.76, p less than 0.001). The increased uptake of 99mTc in the cortical defect that was detected with static scans was attributable not only to the increased blood flow but also to uptake by immature bone. Early dynamic bone-imaging increases the versatility of bone scintigraphy. The significant correlation between the dynamic scans and bone blood flow suggests that this non-invasive technique can provide a quantitative comparison of changes in regional blood flow in bone.