title: Autoradiography of technetium-labelled diphosphonate in rat bone.
abstract: The passage of technetium-labelled methylene diphosphonate (99mTc-MDP) across rat bone was examined by autoradiography. The autoradiographs showed that shortly after an injection of the bone-seeking agent there was activity outside the bone, within the bone marrow and also adjacent to the highly vascular epiphysial plate; the distribution of the isotope in the incubated bone appeared to be non-uniform, a high concentration being seen adjacent to the epiphysial plate and also on the surfaces of the bone. The evidence suggested that a two-fold mechanism resulted in the uneven distribution of 99mTc-MDP. The first factor probably represented the regional distribution of blood flow with a transcapillary movement of the tracer from the capillary bed to the extravascular space; the subsequent incorporation of the tracer into bone appeared to depend on the nature of the bone matrix.
mesh_terms: D000818:Animals; D001345:Autoradiography; D001857:Bone Matrix; D001842:Bone and Bones / Q000098:blood supply / Q000000981:diagnostic imaging / Q000378:metabolism*; D004164:Diphosphonates / Q000378:metabolism; D008297:Male; D011877:Radionuclide Imaging; D051381:Rats; D012039:Regional Blood Flow; D013667:Technetium / Q000378:metabolism
chemical_list: D004164:Diphosphonates; D013667:Technetium