ALARA Concept for MDCT Optimization: What is Reasonable, What is Achievable?
Almost all MDCT scanners are installed with default parameters providing a perfect image quality called “standard”, and deliver the corresponding “standard dose”. Optimization is a process by which a substantial proportion of the standard dose is eliminated without loss in diagnostic performance and/or confidence. The final “optimized dose” reached by this process is not clearly defined in the literature because it varies among manufacturers, scanner generation, and CT users. The ALARA principle implies setting the optimized dose at the lowest reasonable level. In this chapter, we describe possible methods for optimization and propose achievable and reasonable limits for CT scanning of the head, the chest, the abdomen, and the spine.
KeywordsIterative Reconstruction Filter Back Projection Automatic Exposure Control Tube Potential Pitch Factor
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