First Experience With a Whole-Body Spectral Photon-Counting CT Clinical Prototype

Abstract

Spectral photon-counting computed tomography (SPCCT) technology holds great promise for becoming the next generation of computed tomography (CT) systems. Its technical characteristics have many advantages over conventional CT imaging. For example, SPCCT provides better spatial resolution, greater dose efficiency for ultra-low-dose and low-dose protocols, and tissue contrast superior to that of conventional CT. In addition, SPCCT takes advantage of several known approaches in the field of spectral CT imaging, such as virtual monochromatic imaging and material decomposition imaging. In addition, SPCCT takes advantage of a new approach in this field, known as K-edge imaging, which allows specific and quantitative imaging of a heavy atom-based contrast agent. Hence, the high potential of SPCCT systems supports their ongoing investigation in clinical research settings. In this review, we propose an overview of our clinical research experience of a whole-body SPCCT clinical prototype, to give an insight into the potential benefits for clinical human imaging on image quality, diagnostic confidence, and new approaches in spectral CT imaging.

Technical Basics and Clinical Benefits of Photon-Counting CT

“…This system was later upgraded to a preclinical PCD-CT with a field of view (FOV) of 50 cm, a z-coverage of 17.6 mm at the isocenter, and 0.33 seconds of gantry rotation time. 20 This system has been used for large animal and human studies, including cardiac CT. [21][22][23][24] In 2020, the second generation of preclinical PCD-CT with a CdTe detector (SOMATOM CounT Plus; Siemens Healthcare) was installed at 3 clinical institutions. The single-source CT had 0.3 seconds gantry rotation time and was equipped with a detector consisting of subpixels with a size of 0.275 Â 0.322 mm 2 (0.151 Â 0.176 mm 2 at the isocenter).…”

“…This system was later upgraded to a preclinical PCD-CT with a field of view (FOV) of 50 cm, a z-coverage of 17.6 mm at the isocenter, and 0.33 seconds of gantry rotation time 20 . This system has been used for large animal and human studies, including cardiac CT 21–24 …”

Image Quality Analysis of Photon-Counting CT Compared with Dual-Source CT: A Phantom Study for Chest CT Examinations

“…Si-Mohamed et al investigated the differences in image quality and detectability between various CT scanners and algorithms for Philips [ 14 , 16 ]. A smaller noise gap between the DSCT and the PCCT of the Siemens company was observed compared to the Philips CT.…”

“…For the DSCT scanner, the iterative algorithm Advanced Modeled Iterative Reconstruction (ADMIRE) was applied at each iteration level from one to five. Its model is based on the IR algorithm that uses advanced noise reduction methods such as noise and system modeling [ 16 ]. The PCCT scanner was released with a new iterative algorithm, namely, Quantum IR (QIR), with four strength levels.…”

“…Since the first clinical PCCT was released, several technical and clinical studies have been performed and have shown that image quality was improved while keeping the dose constant [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. As the PCCT is used in our thoracic imaging department, the goal of our study was to investigate the PCCT performance in lung nodule detection using physical metrics, which were compared with those obtained using DSCT, which was previously used in the same department.…”