A sensitivity analysis on parameters that affect a multi-step material decomposition for spectral CT
When using a photon counting detector (PCD) for material decomposition problems, a major issue is the low-count rate per energy bin which may lead to high image-noise with compromised contrast and accuracy. We recently proposed a multi-step algorithmic method of material decomposition for spectral CT, where the problem is formulated as a series of simpler and dose efficient decompositions rather than solved simultaneously. While the method offers higher flexibility in the choice of energy bins for each material type, there are several aspects that should be optimized for effective utility of these methods. A simple domain of four materials: water, calcium, iodine and gold was explored for testing these. The results showed an improvement in accuracy with low-noise over the single-step method where the materials were decomposed simultaneously. This paper presents a comparison of contrast-to-noise ratio (CNR) and retrieval accuracy in both single-step and multi-step methods under varying acquisition and reconstruction parameters such as Wiener filter kernel size, pixel binning, signal size and energy bin overlap.
