A mathematical function, with which the brightness distribution (gray tones) of a display can be described from black to white correctly.
The software will adjust your display to the DICOM part14 Gamma.
For further information about DICOM part 14 standards Please refer the following website "http://medical.nema.org/dicom/2004/04_14PU.PDF"
The gamma of CRTs in different displays varies a little, but they are all generally assumed to be 2.5. Non-CRT (fixed-pixel) displays, such as plasma or LCD flat panels, or DLP or LCD projectors, are inherently linear display devices, unlike CRTs, which are inherently nonlinear. Since these newer fixed-pixel displays must properly display the same program material that has been produced for CRTs, however, they must be designed and set up to produce the same 2.5 gamma characteristics as a CRT display. If a fixed-pixel display doesn’t emulate the 2.5 power gamma of a CRT, video program material that has been properly gamma compensated for display on a CRT won’t look right on the fixed-pixel display.
When a manufacturer designs a fixed-pixel display, they build in circuitry that changes the display’s natural linear light output characteristic into a nonlinear characteristic, which is hopefully similar to the 2.5 gamma of a CRT. Oftentimes, though, rather than having just one gamma setup, the manufacturer provides a number of selectable gamma settings. These selectable gamma settings may be in the user menu, or they may be in the service menu. The question then becomes: “what is the proper setting of the gamma selection switch?” The answer is: whichever gamma setting comes closest to providing a 2.5 gamma characteristic, to mimic the gamma of CRT displays.