Investigations of moving-slit radiography.

The technique of moving-slit radiography for reduction of scattered radiation was investigated using a prototype moving-slit radiographic apparatus. Slit widths of 1-2 cm, when used in conjuction with an 8: 1 grid, were found to improve radiographic contrast by a factor of 2 in studies employing physical as well as anatomic phantoms. Use of the moving-slit technique at elevated kVp's was found to provide radiographic contrast as good as or better than that obtained in conventional low-kVp full-field techniques, but with a substantial reduction of patient exposure (factor of 2-4). Considerations in the design of an optimal multislit apparatus are discussed. Excessive tube loading is shown not to be a factor in such a system.