Microdensitometry using a slide projector

We have evaluated a simple microdensitometer concept by Stanton et al. for measurements of dose distributions with high spatial resolution. A magnified image of the film is created by a slide projector and its light intensity measured with a photomultiplier with a small aperture. The projector is placed on a movable stage to allow scanning of the film. A resolution of 17 micron (full width at half maximum of the line spread function) was achieved in the film plane.