Development of DICOM image-based CT low dose simulator using fan-beam transform

BACKGROUND: Projection-data based method is established as an accurate simulation of low-dose CT, but cooperation of the CT manufacturer is required. Image-based method is awaited for independent and efficient research. OBJECTIVE: To develop and verify image-based method for adding noise to DICOM images. METHODS: This technique reproduces projection data by fan-beam transform of the DICOM image data and by creating and reconstructing noise projections into a noise image that can be added to the original image. A cylindrical test phantom and anthropomorphic phantom were used to verify the simulation method for both standard and adaptive iterative reconstruction methods. RESULTS: The simulated images compared favorably with actual images. Standard deviation difference of the simulated images were 1.27% +/- 0.81% (cylindrical phantom) and ranged from 1.61% +/- 0.81% (head), to 5.41% +/- 1.57% (hepatic portal region) (anthropomorphic phantom). The standard deviation difference of the cylindrical phantom with the adaptive iterative technique were 3.41% +/- 1.76% at 50% ASIR and 3.85% +/- 1.82% at 100% ASIR. The simulated noise power spectra of both types of images were comparable to the actual images. CONCLUSION: We developed and validated a DICOM image-based low-dose simulation that allows researchers to perform dose reduction research independently and efficiently.