1. An image producing method causing a computer to execute: a processing step of, in scan data acquired by a radiation CT scan, applying suppression processing with which noise components are suppressed to a high noise level portion having a radiation detection level lower than a specified threshold, and applying enhancement processing with which noise components are enhanced to a low noise level portion having a radiation detection level equal to or higher than the specified threshold; and a reconstructing step of reconstructing an image based on the scan data subjected to the processing by the processing step.