Portable scanning slit device for obese patients.

A portable apparatus with rotating scanning slits has been designed to reduce scatter in the radiographs of obese patients. Rotating scanning slit radiography reduces scatter efficiently, but previous instruments with linear or curved slits have been too heavy to be portable. The author's "dart-board" pattern of multiple sector-shaped holes is theoretically efficient at reducing scatter, compensates for potential ring artifacts by overlapping the holes and expands the holes in the lower plate to account for penumbra. Computer simulation with Monte Carlo techniques shows that the new design is free of concentric ring artifacts. This design should improve the quality of radiographs of very obese patients.