Technical Basics and Clinical Benefits of Photon-Counting CT

Flohr, Thomas; Schmidt, Bernhard

doi:10.1097/rli.0000000000000980

Cited by 48 publications

(27 citation statements)

References 91 publications

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“…10,[12][13][14][15][16][17] It also improves visualization of coronary plaques, especially resulting from calcified lesions, 18,19 and therefore, increases accuracy in quantifying stenosis. 20,21 In addition, PCCT enables the reconstruction of multiple types of images from a single acquisition, offering several advantageous possibilities for enhancing image quality. For example, virtual monoenergetic images (VMI's) are reconstructed images at a specific photon energy level, which provides improved contrast between different tissues.…”

Section: Introductionmentioning

confidence: 99%

Thin slice photon‐counting CT coronary angiography compared to conventional CT: Objective image quality and clinical radiation dose assessment

van der Bie,

Bos,

Dijkshoorn

et al. 2024

Medical Physics

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BackgroundPhoton‐counting CT (PCCT) is the next‐generation CT scanner that enables improved spatial resolution and spectral imaging. For full spectral processing, higher tube voltages compared to conventional CT are necessary to achieve the required spectral separation. This generated interest in the potential influence of thin slice high tube voltage PCCT on overall image quality and consequently on radiation dose.PurposeThis study first evaluated tube voltages and radiation doses applied in patients who underwent coronary CT angiography with PCCT and energy‐integrating detector CT (EID‐CT). Next, image quality of PCCT and EID‐CT was objectively evaluated in a phantom study simulating different patient sizes at these tube voltages and radiation doses.MethodsWe conducted a retrospective analysis of clinical doses of patients scanned on a conventional and PCCT system. Average patient water equivalent diameters for different tube voltages were extracted from the dose reports for both EID‐CT and PCCT. A conical phantom made of polyethylene with multiple diameters (26/31/36 cm) representing different patient sizes and containing an iodine insert was scanned with a EID‐CT scanner using tube voltages and phantom diameters that match the patient scans and characteristics. Next, phantom scans were made with PCCT at a fixed tube voltage of 120 kV and with CTDIVOL values and phantom diameters identical to the EID‐CT scans. Clinical image reconstructions at 0.6 mm slice thickness for conventional CT were compared to PCCT images with 0.4 mm slice thickness. Image quality was quantified using the detectability index (d′), which estimated the visibility of a 3 mm diameter contrast‐enhanced coronary artery by considering noise, contrast, resolution, and human visual perception. Alongside d′, noise, contrast and resolution were also individually assessed. In addition, the influence of various kernels (Bv40/Bv44/Bv48/Bv56), quantum iterative reconstruction strengths (QIR, 3/4) and monoenergetic levels (40/45/50/55 keV) for PCCT on d′ was investigated.ResultsIn this study, 143 patients were included: 47 were scanned on PCCT (120 kV) and the remaining on EID‐CT (74 small‐sized at 70 kV, 18 medium‐sized at 80 kV and four large‐sized at 90 kV). EID‐CT showed 7%–17% higher d′ than PCCT with Bv40 kernel and strength four for small/medium patients. Lower monoenergetic images (40 keV) helped mitigate the difference to 1%–6%. For large patients, PCCT's detectability was up to 31% higher than EID‐CT. PCCT has thinner slices but similar noise levels for similar reconstruction parameters. The noise increased with lower keV levels in PCCT (≈30% increase), but higher QIR strengths reduced noise. PCCT's iodine contrast was stable across patient sizes, while EID‐CT had 33% less contrast in large patients than in small‐sized patients.ConclusionAt 120 kV, thin slice PCCT enables CCTA in phantom scans representing large patients without raising radiation dose or affecting vessel detectability. However, higher doses are needed for small and medium‐sized patients to obtain a similar image quality as in EID‐CT. The alternative of using lower mono‐energetic levels requires further evaluation in clinical practice.

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Section: Introductionmentioning

confidence: 99%

Thin slice photon‐counting CT coronary angiography compared to conventional CT: Objective image quality and clinical radiation dose assessment

van der Bie,

Bos,

Dijkshoorn

et al. 2024

Medical Physics

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“…New CT scanners use photon-counting detectors (PCD). In contrast to EID, PCDs are able to directly convert X-ray photons into an electric signal using semiconductors [5]. Based on this groundbreaking technology, PCD-CT can overcome many limitations of EID-CT.…”

Section: Introductionmentioning

confidence: 99%

“…Based on this groundbreaking technology, PCD-CT can overcome many limitations of EID-CT. The main advantages of PCD-CT are the elimination of electronic noise, the improvement of spatial resolution, the intrinsic spectral imaging capabilities, and the potential reduction of radiation dose [2,3,5,6,7,8].…”

Section: Introductionmentioning

confidence: 99%

Photon-counting detector CT – first experiences in the field of musculoskeletal radiology

Bette,

Risch,

Becker

et al. 2024

Rofo

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The introduction of photon-counting detector CT (PCD-CT) marks a remarkable leap in innovation in CT imaging. The new detector technology allows X-rays to be converted directly into an electrical signal without an intermediate step via a scintillation layer and allows the energy of individual photons to be measured. Initial data show high spatial resolution, complete elimination of electronic noise, and steady availability of spectral image data sets. In particular, the new technology shows promise with respect to the imaging of osseous structures. Recently, PCD-CT was implemented in the clinical routine. The aim of this review was to summarize recent studies and to show our first experiences with photon-counting detector technology in the field of musculoskeletal radiology.We performed a literature search using Medline and included a total of 90 articles and reviews that covered recent experimental and clinical experiences with the new technology.In this review, we focus on (1) spatial resolution and delineation of fine anatomic structures, (2) reduction of radiation dose, (3) electronic noise, (4) techniques for metal artifact reduction, and (5) possibilities of spectral imaging. This article provides insight into our first experiences with photon-counting detector technology and shows results and images from experimental and clinical studies.Bette S, Risch F, Becker J et al. Photon-counting detector CT – first experiences in the field of musculoskeletal radiology. Fortschr Röntgenstr 2024; DOI 10.1055/a-2312-6914

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“…This approach provides valuable and detailed information about the composition of various elements. 10,14–18 One of the main advantages of SPCCT is its ability to perform material identification and quantification of different materials based on their density, atomic composition, and energy-dependent attenuation. Unlike conventional CT or even DECT systems, SPCCT can effectively distinguish between different contrast agents with similar X-ray attenuation properties.…”

Section: Introductionmentioning

confidence: 99%