%0 Journal Article %A Ruud Ramakers %A Brendan Vastenhouw %A Freek Beekman %T Ultra-high resolution cardiac SPECT of frozen animals as an alternative to autoradiography %D 2009 %J Journal of Nuclear Medicine %P 1468-1468 %V 50 %N supplement 2 %X 1468 Objectives Cardiac gating is often used during SPECT acquisition in order to suppress motion induced blurring artifacts. Recently, sub-half-mm resolution gated images of the mouse myocardium have been obtained. Details like papillary muscles can be readily detected. Here we investigate if imaging of a frozen animal results in even more detailed imaging. Methods An anesthetized mouse was intravenously injected with 500MBq of Tc-99m-tetrafosmin. The animal was placed in a polymethylmethacrylate cylinder and was euthanized by placing it in liquid nitrogen. Cardiac images of the mouse were obtained using a stationary SPECT system with 75 focusing 0.35mm pinholes (U-SPECT-II, MILabs, The Netherlands). The animal was scanned for 300 minutes and the temperature was kept below minus thirty degrees Celsius. Results The proposed method generated images of superior image quality compared to live in vivo images. Specifically (i) every part of the right ventricular wall is extremely clearly visible, (ii) both the left and right ventricular and atrial walls are readily visible and (iii) there is a lower noise level than in vivo SPECT images. Conclusions We developed an efficient method for extremely high-resolution 3D radionuclide imaging as an alternative to tedious autoradiography methods. It provides ex vivo images with lower noise and a somewhat higher resolution than can be achieved with in vivo SPECT. %U