The method includes acquiring the gray tone images, and plotting a histogram of {TAIL ~ the average pixel signal intensities} for selected regions of interest in {HEAD ~ each image} 
The method includes acquiring the gray tone images , and plotting a histogram of { TAIL ~ the average pixel signal intensities } for selected regions of interest in { HEAD ~ each image }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD