Moiré interference in gamma camera quality assurance images.

Moiré interference effects have been noted in gamma camera images for some time. Recent work has shown that the effects are still prevalent with the current generation of cameras, though apparently dependent upon collimator design. All previous work has been related to bar phantom images only. This paper also demonstrates a variety of moiré effects using the Anger "pie" phantom. Some of the principles underlying moiré interference as they apply to gamma cameras are given and possible uses of the effects are discussed, as well as the limitations they impose upon the use of certain test objects in routine quality assurance testing.