Inexpensive fiber optic two-dimensional densitometer for the high-resolution quantitation of autoradiogram grain densities.

The design and construction of a simple, low cost high performance fiber optic 2-dimensional microdensitometer is described. With this instrument the film to be quantitated is placed upon a back-lit frosted glass bench and scanned with an optic fiber probe attached to a transparent micromanipulator. The emerging light is transported by the fiber to the photocell of a direct reading spectrophotometer. The resulting numerical data can either be transcribed, portrayed on a recorder or entered into the memory of a microdata processor for further analysis and comparisons. The instrument was sensitive to very small differences in optical density and could resolve lines 100 but not 30 micrometers apart. It was precise, reliable and easy to build. With the use of this equipment many previously undetected, significant local brain glucose utilization differences were quantitated in groups of unrestrained rodents, maintained in several behavioral states.