Digital radiography: Detector Latitude

This weeks topic on digital radiography is detector latitude.  Detector latitude is the ability of a receptor to capture a range of x ray exposures.  The term used to describe this is magnitude.  Analog film has a large range of magnitudes from 0.5 to 4, however, only under bright illumination (film held next to bright light in a dark room) can the last two magnitudes (3 and 4) be seen.  Digital radiography (sensors) has the same range of magnitudes as film (0.5 to 4).  The last two magnitudes can be viewed by adjusting the contrast and brightness of the image.  Computed radiography (phosphor plates) has a slightly larger range of magnitudes (0.5 to 5).  Again the magnitudes past 2.5 can be viewed by adjusting the contrast and the brightness of the image.

The diagnostic range of detector latitude is 2 magnitudes (0.5 to 2.5).  While both digital systems (digital radiography and computed radiography) and analog film are capable of showing higher magnitudes than this range, they do not provide a superior diagnostic image.  Any magnitude past 2.5 can only be seen by adjusting contrast and brightness (digital radiography and computed radiography) or with bright illumination (analog film).

I hope this information about detector latitude is helpful.  If you have any questions or comments, please let me know.

Thanks and enjoy!