σ B = standard deviation of the background ROI counts, corresponding to noise in the image.
SD j = standard deviation of the background ROI counts for sphere j.
The mean and standard deviation of the background activity within this annulus region were measured and recorded.
The detection limit was calculated as 3 times the standard deviation of the background level and ranged between 1.3 and 3.8 ppb.
The coefficient of variation (COV) is given by COV = σ bg/N bg, where σ bgis the standard deviation of the background ROI.
The average and range of percent contrast obtained for hot and cold spheres, the average and range of the standard deviation of the background counts, and the mean residual error for the scatter and attenuation corrections were evaluated.
The grading provides an evaluation of the difference between the TB score (and if there is more than one target, the mean of the TBs) and the mean of the background blocks, normalized by the standard deviation of the background.
The mean background and the standard deviation of the background were measured in 19 VOIs, equal in size to the signal VOI, and placed in the central plane of the phantom.
The LOD and LOQ were computed three times and ten times, respectively, of the standard deviation of the background signal from ten measurements divided by the slope of the calibration equation.
where is the magnitude of the 3 dB point of the p th target signature in the 3D model generated by the proposed algorithm and is the standard deviation of the background noise.
The average (and range) percent contrast obtained for hot and cold spheres, the average (and range) standard deviation of the background counts, and the mean residual error in scatter and attenuation corrections were evaluated.
