Patent US 4,460,832

A nuclear radiation attenuator for providing a test image from a source of radiation is disclosed. The attenuator provides a test image including a plurality of discrete target images located in a background image. Each target image has an intensity that differs from the intensity background image to provide a target to background contrast ratio for each target image. A plurality of the target images each have a different contrast ratio so that the contrast ratios of the target simulate contrast ratios found in clinical testing. The attenuator provides a standardized test image that enables the performance of a scintillation camera to be tested routinely.