Gamma-camera linearity and resolution assessed using coarsely sampled line spread functions

The measurement of gamma-camera linearity and resolution forms an important part of acceptance testing and routine quality control. Conventional techniques for measuring locations and widths of line spread functions require high precision digitization, usually via external analogue to digital converters. A technique is described for accurate measurement of peak location and width using coarsely sampled line spread functions. Results obtained for both simulated and actual gamma-camera data demonstrate that the method is capable of measuring peak deviations as small as 0.2 mm when the sampling interval is 1.5 mm or more. The precision of the method was found to be at least as good as conventional techniques. It is suggested that using the method accurate measurements of linearity can be made from a conventional 256 x 256 nuclear medicine image of a slit mask, and this enables routine evaluation of an important parameter of camera performance. (author)