Abstract
As to the relationship between radiation dose and image quality in X-ray CT examinations, one can say, “the more radiation exposure we give, the better image quality we get”, as in the other X-ray examinations. Therefore, this relationship is a so-called trade-off relation, and it is a fundamental rule that radiation dose should be as low as possible under constraints to maintain diagnostic performance. Because the effects of image quality improvement by reducing radiation dose are expected to show “saturation” behavior as many natural phenomena, this improvement problem can be solved to a certain extent as an optimization problem. In this paper, I give an outline of some important research results that have been done for the relationship between radiation dose and image quality in X-ray CT examinations.
