New Approach to Quantification of Molecularly Targeted Radiotracer Uptake from Hybrid Cardiac SPECT/CT: Methodology and Validation

 Illustrations of CT epicardial edge (A), correction map for extracardiac activity correction (B), LV myocardial volume in CT with unit activities assigned (C), and correction map for partial-volume effect generated by convolving binary CT image shown in C with PSF (D).

 Illustrations of in vivo CT short-axis slice with segmented LV cavity colored in red (A), in vivo CT short-axis slice with LV myocardium (in green) superimposed (B), and in vivo SPECT short slice of α_vβ₃-targeted image with LV myocardium superimposed (C).

 Demonstrations of in vivo SPECT short-axis slice of α_vβ₃-targeted image with region of interest (A), segmented LV myocardium volume in same SPECT slice before extracardiac activity correction (B), and SPECT slice after extracardiac activity correction (C).

 Comparisons between SPECT-quantified and well-counted radioactivities for representative SPECT slice shown in Figure 4. Green curve shows true well-counted radioactivity. Red and black curves demonstrate SPECT-quantified radioactivity with and without corrections, respectively.