Development of a computer simulation technique for low-dose chest radiographs: a phantom study.

The present study aimed to develop a simple computer simulation method of low-dose radiographs based on a radiograph acquired at a clinical-dose level. A chest phantom was used for the development of this method. In this method, a simulated low-dose image was obtained from a clinical-dose image using an input-output characteristic curve of a flat panel detector and noise metrics of the standard deviation (SD) and noise power spectrum. We applied this method for low-dose images of a chest phantom to evaluate the simulation accuracy. The noise SDs were compared between the simulated and real images corresponding to 1/2, 1/4, and 1/8 of clinical doses. The relative error of noise SDs in the chest phantom images was less than 3%. Therefore, we believe that the proposed simulation method has the potential to be useful for determination of the optimal exposure condition in chest radiography to reduce patients' exposure dose.