The histogram of the viewed image can be displayed in the top right corner of the image window.
The range of pixels presented by the histogram is equal to the bits stored value in the DICOM header.
Use the histogram in combination with the brightness/contrast tool to set the best brightness and contrast.
Just below the histogram, a grayscale bar is displayed. The start and end values of the grayscale palette, are displayed with the yellow lines inside the histogram.
Histogram of an 8-bit (256 gray levels) image