Single-Energy Material Decomposition Using X-Ray Path Length Estimation

Objective: Clinical computed tomographies (CTs) can typically use only a single energy at a time. The main purpose of the present paper was to study whether the calculated x-ray path lengths can help replace one of the 2 dual-energy measurements by 2-material decomposition. Method: The proposed single-energy material decomposition method (SEMD) is based on the evaluation of a single CT scan. The SEMD combines postreconstruction and prereconstruction algorithms for the determination of x-ray path length and material decomposition, respectively. Results: The simulation results of the proposed and dual-energy methods were compared using pregenerated look-up tables. The results show that SEMD is more sensitive to CT signal errors at higher tube voltages. The dual-energy method is generally less sensitive to CT signal bias but more sensitive to the noise. Conclusions: In the case of inferior signal errors, the proposed method gives the same results as the dual-energy variant. Although the x-ray path length estimation method with SEMD is more complex, the dose is considerably lower.