Physical interpretation of diaphanograms using the computer-controlled image scanner OSIRIS.

Experiments have shown that the light recorded in diaphanography covers approximately the wavelength region of 645 to 900 nm. No significant change in image quality was noted by changing the camera distance between 10 and 25 cm and the light source aperture between 5 and 30 mm. Experiments using polarising filters indicated that the breast is optically isotropic; therefore the results cannot be improved by using polarising filters. In a comparison of various films. Kodak Ektachrome Infrared Film gave the best results. No degradation or variation in image quality was observed when different batches were compared or when the exposed film was stored for 3 weeks before processing. The exposure level is a critical factor and a series of 3 images is needed for optimum evaluation of diaphanograms. The experiments indicate that diaphanography gives consistent results.