99mTechnetium-methylene diphosphonate bone imaging using low-intensity pulsed ultrasound: promotion of bone formation during mandibular distraction osteogenesis in dogs

Our objective was to assess the value of 99mtechnetium-methylene diphosphonate (99mTc-MDP) bone imaging in the use of low-intensity pulsed ultrasound to promote bony formation during mandibular distraction osteogenesis in dogs. The body of the mandibles in 7 dogs were cut between the first and the second premolar and were lengthened at the rate of 1 mm/day, twice a day, for 20 days. During the period of distraction one lateral distraction gap was irradiated with low-intensity pulsed ultrasound (LIPUS) for 10 min twice a day, and the other side was used as control. Serial radiographic inspections were made at different periods (0, 1, 2, 4, 6, 8, and 12 weeks) during the consolidation phase, followed by a plain radiograph and histological examination. The 99mTc-MDP imaging showed that the ratio of bone formation on the LIPUS-treated side was significantly higher than that on the control side during the early period of consolidation (before the 4th week), but later this was reversed and there were no significant differences between the two sides by the 12th week. Plain radiographs and histological examination showed that the new bone on the experimental side had matured earlier than that on the control side. Radionuclide bone imaging is a good way to assess the formation of bone after distraction osteogenesis.