Single-energy material decomposition using X-ray path length estimation

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.

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.

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.

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.