Imaging radiation induced muscular necrosis with antimyosin-scintigraphy and computed tomography.

Radiations accidents involving high exposures require accurate assessment of radiation dose for correct surgical or medical management. Techniques involving computed tomography and antimyosin-antibody scintigraphy were evaluated in an experimental model of acute localized irradiation overexposure to 192Ir. Ten rabbits were exposed to a single dose of 192Ir gamma irradiation (120 Gy) on the back (right iliospinal muscle). Computed tomography and antimyosin-antibody scintigraphy results were compared with those in four control animals. Planar scintiscans (posterior views) were performed 48 h post-injection of antimyosin-antibody each week for 2 mo after exposure. An antimyosin uptake was observed in irradiated muscle five weeks after exposure and correlated with computed tomography and histopathology results, showing muscle necrosis. Biodistribution assessed at 7 and 9 wk post exposure confirmed antimyosin-antibody accumulation in damaged muscle. A semi-quantitative analysis of a region of interest over the uptake area in the irradiated muscle (on the right side) and a contralateral non-irradiated region of interest used as control showed that uptake was significantly higher in irradiated animals than in control animals (p < 0.02). Antimyosin-antibody scintiscans used in nuclear cardiology to explore ischemic heart disease, myocarditis or heart transplant rejection could be realized to assess the extent of muscle necrosis after trauma or radiation induced injury.