A protocol-based evaluation of medical image digitizers

Medical film digitizers play an important transitory role as digital-to-ana logue bridges in radiology. Their use requires performance evaluation to as sure medical image quality. A complete quality control protocol is presente d, based on a set of test objects adaptable to the specification of various digitizers. The protocol includes parameters such as uniformity, input-out put response, noise, geometric distortion, spatial resolution, low contrast discrimination, film slippage and light leakage, as well as associated mea surement methods. The applicability of the protocol is demonstrated with tw o types of medical film digitizers; a charge-coupled device (CCD) digitizer and a laser digitizer. The potential value of the protocol is also discuss ed.