Reduction of patient dose in digital mammography: simulation of low-dose image using computed radiography system and flat panel detector system

Abstract

To reduce the patients’ exposure, several low-dose images are necessary to obtain an image that can be used for diagnosis. However, it is clinically undesirable to expose a patient to multiple exposures in order to obtain an optimal image. The purpose of this study was to simulate a low-dose image from the image generated by a routine-dose. Images of acrylic steps were obtained using multiple doses in digital mammography to generate additional noise. The additional noise was calculated as three different noise sources. This study used the digital mammography system with different detectors. It is computed radiography (CR) system and flat panel detector (FPD) system. This noise was added to take into account the resolution of the X-ray detector using the following filters. The filters were designed based on the presampled modulation transfer function (MTF) and digital MTF containing aliasing. The image simulated using the presampled MTF filter was less similar to an actual low-dose image using the CR system. The image simulated using the digital MTF filter was closer to an actual low-dose image compared to the image simulated using the presampled MTF filter using the CR system. The image simulated using the digital MTF filter of the FPD system was similar to an actual low-dose image. By using the proposed method, we were able to obtain a simulated low-dose image from an image generated by a routine-dose.