2001 Volume 3 Issue 4 Pages 251-256
Low contrast resolutions in the CT unit is carried out in accordance with the second recommendation proposal compiled by the X-ray CT commission. The recommended method alters the diameter of the signal to its minimum identifiable size. This is in order to enable the observer to detect this signal visually and perform an evaluation of the system. ROC analysis is widely used as an objective method for evaluation of images. This method was originally developed for evaluation of the measuring capacity of radar. Accordingly, ROC analysis can be applied to achieve objective evaluation of the detection properties of image diagnosis apparatuses in terms of their physical capacity. The ROC analysis measurement method for low contrast resolutions introduced by Shiraishi, allows for the objective evaluation of the detection characteristics in the CT unit. This time, we used this new method to measure the resolution of low contrast resolutions in the CT unit. We will report on the relationship between the tube current, slice thickness, X-ray dose absorption, reconstruction function and low contrast resolution, all of which have been difficult to evaluate in the past. The method prescribed by Shiraishi, sensitively captures any changes in the low contrast resolution of the CT unit that occurs due to the varying conditions. A1so because low contrast varying resolutions could easily be evaluated using the Shiraishi method, it is thought that this is a further step in the effective evaluation of low contrast resolutions.
