First-generation clinical dual-source photon-counting CT: ultra-low dose quantitative spectral imaging

Objective Evaluation of quantification capabilities at ultra-low radiation dose levels of a first-generation dual-source Photon-Counting Computed Tomography (PCCT) compared to a dual-source dual-energy CT (DECT) scanner. Methods A multi-energy CT phantom was imaged with and without extension ring on both scanners over a range of radiation dose levels (CTDI vol 0.4 - 15.0 mGy). Scans were performed in different modes of acquisition for PCCT with 120 kVp and DECT with 70/Sn150 kVp and 100/Sn150 kVp. Various tissue inserts were used to characterize the precision and repeatability of Hounsfield Units (HUs) on virtual mono-energetic images between 40 and 190 keV. Image noise was additionally investigated at ultra-low radiation dose to illustrate PCCT’s ability to remove electronic background noise. Results Our results demonstrate high precision of HU measurements for a wide range of inserts and radiation exposure levels with PCCT. We report high performance for both scanners across a wide range of radiation exposure levels with PCCT outperforming at low exposures compared to DECT. PCCT scans at lowest radiation exposures illustrate significant reduction in electronic background noise, with a mean percent reduction of 74% (p-value ∼10 −8 ) compared to the 70/Sn150 kVp and 60% (p-value ∼10 −6 ) compared to the 100/Sn150 kVp. Conclusions This paper reports first experiences with a clinical dual-source PCCT scanner with Quantum technology. PCCT provides reliable HUs without disruption from electronic background noise for a wide range of dose values. Diagnostic benefits are not only for quantification at ultra-low-dose but also for imaging of obese patients. Key Points PCCT scanners with Quantum technology provide precise and reliable quantitative Hounsfield Units at ultra-low-dose levels. Influence of electronic background noise can be removed at ultra-low dose acquisitions with PCCT. Both spectral platforms have high performance along a wide range of radiation exposure levels with PCCT outperforming at low radiation exposures.