Method for evaluation of low-contrast detectability in X-ray CT

Generally speaking, X-ray CT is more dependable than other X-ray examinations, because it is more precise for low-contrast detectability. Therefore, when we try to estimate the ability of CT equipment, we should focus on the high accuracy of low-contrast detectability. We were able to conclude that we could estimate low-contrast detectability easily with a numerical value by applying the official approval of significant difference in statistics. For example, the necessary differences of CT number to detect about 5 cm diameter object are 3.66, 2.59 and 1.83 for doses 115, 230 and 460 mAs with the filter function of the head mode. Then, we used the value 0.01 % level of significance. (author)