What’s New in Photon Counting CT?

September 22, 2026 · 9 articles · 9 research themes · covering September 15, 2026 – September 22, 2026

Overview

Across this week’s set of studies, photon-counting CT (PCCT) is advancing along two parallel tracks: (1) establishing how to run PCCT reliably at lower dose and across acquisition settings, and (2) translating those capabilities into clinically actionable imaging for cardiovascular, pulmonary, and otologic workflows. Phantom and prospective human data emphasize dose–noise and quantitative stability—showing that tin-filtered pediatric chest protocols and ultra-low-dose lung PCCT can be optimized to preserve diagnostic image quality and maintain performance of automated quantitative CT metrics.

On the clinical translation side, PCCT is being tested as a high-fidelity tool for small-structure and high-stakes assessments. In coronary CTA, PCCT’s diagnostic accuracy for in-stent restenosis is evaluated against invasive angiography, while time-resolved PCD-CT metrics are assessed for post–TAVI prosthetic valve dysfunction. In atrial fibrillation, PCCT-derived 3D epicardial adipose tissue volumes are linked to arrhythmia recurrence after ablation, supporting a move toward PCCT-based body composition phenotyping as a risk stratifier. For otosclerosis, temporal bone PCCT is shown to reveal preoperative imaging signs that may be missed in radiology reports, highlighting potential value for surgical planning.

Finally, the technical foundation for broader adoption is strengthened by studies on spectral/virtual monoenergetic behavior and detector physics: kV dependence of VMI CT values and contrast-to-noise ratios is quantified, informing standardization of quantitative spectral outputs. Complementing this, a theranostic-oriented study demonstrates that SPCCT acquisition parameters can modulate fluorescence from surface-functionalized GdTbF3 nanoparticles, providing practical guidance for combining nanoparticle fluorescence with photon-counting spectral imaging. A narrative review further consolidates PCCT’s head-and-neck advantages—improved spatial resolution, reduced noise/metal artifacts, and lower contrast dose—into a roadmap for clinical implementation.

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PCCT in Pediatric Imaging (Chest Protocols & Phantom Validation)

Pediatric Chest Photon-counting CT: Dose and Noise Behavior of Clinical Sn100 kVp and 90 kVp Protocols across Image Quality Levels - a Phantom Study.

This phantom study compared a clinical tin-filtered Sn100 kVp ultra-high-resolution photon-counting CT (PCCT) protocol versus a non-tin-filtered 90 kVp standard-resolution protocol in three anthropomorphic pediatric chest phantoms (1, 5, and 10 years) across image quality levels (IQLs 1–300). The key finding was the characterization of how radiation dose and image noise change with IQL for these clinically implemented pediatric chest protocols, highlighting protocol-dependent dose–noise behavior attributable to the Sn100 kVp tin filtration and PCCT acquisition. These results support evidence-based optimization of pediatric PCCT chest protocols to maintain diagnostic image quality while minimizing dose and noise.

Klüner LV, Zensen S, Peuster H et al. · RoFo : Fortschritte auf dem Gebiete der Rontgenstrahlen und der Nuklearmedizin · (2026) · View on PubMed ↗

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Spectral Photon-Counting CT for Nanoparticle Activation & Theranostics

Optimizing x-ray based multimodal imaging: investigating dose dependency and modulation of fluorescence emission from GdF3nanoparticles doped with terbium using spectral photon counting CT.

This study investigated how spectral photon-counting CT (SPCCT) acquisition parameters influence x-ray–induced activation and imaging performance of surface-functionalized gadolinium terbium fluoride nanoparticles (GdTbF3 NPs) using terbium-doped GdF3-based agents. The key finding was that SPCCT irradiation and acquisition settings modulate fluorescence emission from the GdF3:Tb (GdTbF3) nanoparticles, enabling optimization of activation and imaging protocols. This is significant because it provides parameter guidance for combining nanoparticle fluorescence with SPCCT to improve contrast and potentially enable theranostic workflows.

Akl P, Gautheron A, Antonuccio MN et al. · Physics in medicine and biology · (2026) · View on PubMed ↗ · Free PDF ↗

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PCCT in Coronary Imaging (Stents & In-Stent Restenosis)

In vivo coronary stent evaluation using photon-counting computed tomography: diagnostic performance.

In a retrospective single-center study of 141 consecutive patients with coronary stents undergoing coronary CTA, photon-counting CT (PCCT) was compared with energy-integrating detector (EID)-CT for diagnostic performance in detecting in-stent restenosis (ISR) ≥50% using invasive coronary angiography as reference. The key finding was the assessment of PCCT’s diagnostic accuracy and image quality for ISR detection, including how image quality of the in-stent lumen related to diagnostic categorization. Clinically, this supports whether PCCT coronary angiography can improve detection of clinically relevant ISR while maintaining or enhancing stent visualization quality.

Lacaita PG, Bilgeri V, Spitaler P et al. · European radiology · (2026) · View on PubMed ↗ · Free PDF ↗

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PCCT for Temporal Bone/Otosclerosis Surgical Planning

Photon-counting CT for preoperative assessment of stapes footplate fixation in otosclerosis.

This retrospective case series evaluated photon-counting CT (PCCT) findings in 18 surgically confirmed otosclerosis patients who underwent temporal bone PCCT (March 2023–December 2024) to identify stapes footplate fixation. The key finding was the frequency with which preoperative radiology reports missed imaging signs of stapes footplate involvement (e.g., increased thickness or hypoattenuation) when compared with intraoperative surgical findings. This is significant because it quantifies the diagnostic value and potential reporting gaps of PCCT for preoperative planning in otosclerosis surgery.

Arora M, Seyedsaadat SM, Breen JT et al. · European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery · (2026) · View on PubMed ↗

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PCCT for Lung Imaging (Dose Reduction & Quantitative Metrics)

Quantitative and qualitative lung parameters in photon-counting CT: comparison of ultra-low-dose with standard low-dose protocols.

In a prospective same-session study of 101 patients, ultra-low-dose (ULD) photon-counting CT (PCCT) was compared with standard low-dose (LD) PCCT to determine effects on quantitative and qualitative lung parameters. The key finding was how ULD acquisition impacts automated quantitative CT (QCT) metrics—such as noise index, airway segmentation and wall percentage, emphysema index (EI), mean lung density (MLD), and Percentile 15 (Perc15)—and how these changes translate into reader-scored image quality for airways and emphysema. This is clinically important for defining safe dose-reduction limits in PCCT lung imaging without compromising quantitative assessment.

Kroschke J, Jungblut L, von Stackelberg O et al. · European radiology · (2026) · View on PubMed ↗ · Free PDF ↗

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PCCT in Cardiac Valve Assessment (TAVI & Hemodynamics)

Photon-counting detector CT for prediction of valve dysfunction after transcatheter aortic valve implantation: Comparison with echocardiography.

This retrospective single-center study screened post–transcatheter aortic valve implantation (TAVI) patients who underwent time-resolved photon-counting detector CT (PCD-CT) between January 2023 and December 2025, comparing CT-derived hemodynamic parameters for prosthetic valve dysfunction against echocardiography. The key finding was the diagnostic accuracy of PCD-CT–derived functional metrics (after excluding cases with severe mitral regurgitation and using CT measurements such as systolic prosthetic valve orifice area) for identifying suspected valve dysfunction. This is significant because it evaluates whether time-resolved PCD-CT can noninvasively provide both anatomic and hemodynamic information to improve post-TAVI assessment.

Hyska S, Osoria-Velasquez J, Hagar MT et al. · Journal of cardiovascular computed tomography · (2026) · View on PubMed ↗ · Free PDF ↗

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PCCT for Atrial Fibrillation Risk Stratification (Body Composition & EAT)

Epicardial adipose tissue in paroxysmal and persistent atrial fibrillation ablation using photon counting CT and automated 3D atrial segmentation: The Prospective AFAT Study.

In the prospective AFAT study, 210 adults undergoing first-time catheter ablation for paroxysmal or persistent atrial fibrillation underwent preprocedural photon-counting CT (PCCT) with semiautomated 3D biatrial segmentation to quantify epicardial adipose tissue (EAT) volumes. The key finding was the association between quantified biatrial EAT (from PCCT-based 3D reconstruction) and arrhythmia recurrence after ablation. This is significant because it supports PCCT-based body composition phenotyping as a potential predictor of ablation outcomes in AF.

Erhard N, Bahlke F, Prommersberger S et al. · Heart rhythm · (2026) · View on PubMed ↗ · Free PDF ↗

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PCCT in Head & Neck Imaging (Review/Clinical Translation)

Photon-counting CT in head and neck radiology: bridging detector physics and clinical applications.

This narrative review summarized how photon-counting CT (PCCT) advances head and neck imaging compared with energy-integrating detector CT (EID-CT), focusing on detector physics and clinical applications. The key finding was the consolidation of PCCT’s technical advantages—improved spatial resolution, reduced noise and metal artifacts, lower radiation exposure, reduced iodinated contrast dose, and spectral imaging—into practical benefits for visualizing small vessels, ossicles, and cartilage for preoperative planning and postoperative assessment. This is significant for guiding clinical adoption of PCCT protocols and highlighting where PCCT may improve diagnostic confidence in head and neck workflows.

Martín-Noguerol T, Escartín J, López-Úbeda P et al. · European radiology · (2026) · View on PubMed ↗

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Spectral/Virtual Monoenergetic Quantification & kV Dependence

Influence of X-ray Tube Voltage on Computed Tomography Values and Contrast-Noise Ratios in Virtual Monoenergetic Images in routine clinical Photon Counting Detector Computed Tomography: Does kV Still Matter?

This phantom study evaluated how x-ray tube voltage (kV) affects computed tomography values and contrast-to-noise ratios in virtual monoenergetic images (VMIs) generated from routine clinical photon-counting detector CT (PCD-CT). The key finding was the degree to which VMI CT values and CNR remain dependent on kV across tissue types, VMI keV levels, phantom sizes, and different kV settings—addressing whether kV still matters for quantitative spectral outputs. This is significant because it informs standardization and quantitative reliability of PCD-CT VMIs across scans performed with different tube voltages.

Jeukens CRLPN, Pinckaers FME, Martens B et al. · Investigative radiology · (2026) · View on PubMed ↗ · Free PDF ↗

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Generated automatically on September 22, 2026. Covers PubMed articles published September 15, 2026 – September 22, 2026. Summaries are AI-generated; always consult the original publication for clinical or research decisions.