What’s New in Photon Counting CT?

May 06, 2026 · 27 articles · 15 research themes · covering April 29, 2026 – May 06, 2026

Overview

Across this week’s set of studies, photon-counting CT (PCCT/PCD-CT) is repeatedly positioned as a next-generation platform for more reliable quantitative imaging—especially where conventional energy-integrating CT struggles. The dominant technical themes are (1) improved spectral separation (e.g., Gd K-edge vs calcium to reduce calcification-related lumen ambiguity), (2) better spatial resolution and reduced blooming for tiny structures and heavily calcified anatomy (coronary arteries, middle ear prostheses), and (3) more robust quantitative performance through physics-aware reconstruction and post-processing (scatter modeling, noise propagation through spectral decomposition, and reduced CT-number location dependence). Together, these advances aim to make CT-derived biomarkers more consistent across scanners, patients, and clinical workflows.

Clinically, the strongest momentum is in cardiovascular and thoracic applications. Multiple coronary CT angiography papers—spanning severe calcification, lumen assessment, and automated plaque quantification—suggest that UHR photon-counting systems can improve visualization and diagnostic confidence by mitigating calcification blooming and enabling more stable quantitative measurements. In the lung, UHR photon-counting CTPA shows improved peripheral pulmonary artery visibility and confidence for detecting distal emboli, while other thoracic work explores low-dose feasibility and physics-based nodule detectability. Beyond imaging performance, several studies extend PCCT value into downstream decision-making: radiotherapy planning (CT-number robustness for dose calculations), proton therapy range uncertainty (virtual PCCT stopping power), and cardiac/ablation planning via CT-derived atrial thickness and adipose anatomy.

Finally, the digest highlights growing translational breadth—moving from imaging physics into disease-specific biomarkers and clinical pathways. Hepatic studies use PCCT-derived fat fraction and extracellular volume to align with MRI and to noninvasively risk-stratify portal hypertension, while head/neck and musculoskeletal work leverages PCCT’s resolution to improve lesion/prosthesis characterization (parathyroid adenomas, COCD features). Reviews and qualitative assessments (including SWOT-style neuroradiology evaluation and implementation roadmaps) reinforce that the field is actively mapping where PCCT’s spectral and resolution advantages are most likely to translate into measurable clinical benefit, while acknowledging ongoing implementation and evidence-generation needs.

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Photon-Counting CT Physics, Reconstruction, and Noise/Scatter Modeling

Spectral deep learning-based patient and bowtie scatter correction for clinical photon-counting CT.

The research investigated whether spectral information from photon-counting CT can improve deep learning–based scatter correction by explicitly modeling how energy-threshold–dependent scatter signatures differ for patient scatter and bowtie-filter scatter. The key finding is that a spectral deep learning approach can exploit photon-counting energy discrimination to better estimate and correct scatter than conventional non-spectral methods. This is significant because more accurate scatter correction can improve quantitative CT image quality and downstream tasks (e.g., material decomposition and radiotherapy planning) in clinical photon-counting CT.

Hennemann L, Erath J, Heinkele A et al. · Medical physics · (2026) · View on PubMed ↗

Self-Supervised Denoising With Noise Propagation Model: Improving Material Decomposition in Photon-Counting CT.

The study developed a self-supervised deep learning denoising framework that incorporates a physics-based noise propagation model to improve spectral material decomposition in photon-counting CT (PCCT). It found that explicitly modeling detector photon-count variability and propagating its noise through the decomposition process can better control noise amplification during material decomposition than denoising methods that only target already-degraded images. This is significant because it can improve quantitative material separation in PCCT while reducing noise/artifact buildup, enabling more reliable spectral imaging for clinical material characterization.

Wu Q, Ji X, Lei X et al. · IEEE transactions on bio-medical engineering · (2026) · View on PubMed ↗

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Radiation Dose Reduction and Pediatric/Low-Dose Imaging

Photon-counting Detector CT Enables Pediatric Low-dose Chest Imaging With Further Reduction of Radiation Exposure.

The study retrospectively compared pediatric unenhanced low-dose chest photon-counting detector CT (PCD CT) with conventional energy-integrating detector CT (EID CT) in children matched by water-equivalent diameter and age (n=44 per group). It found that PCD CT could further reduce radiation exposure while maintaining or improving quantitative and qualitative image quality for frequently acquired pediatric low-dose lung imaging. This is clinically significant because it supports broader use of photon-counting CT to lower dose in children without sacrificing diagnostic performance.

Krueger MB, Werncke T, Eicke M et al. · Investigative radiology · (2026) · View on PubMed ↗

Photon-Counting Detector CT Versus Conventional CT for Low-Dose Chest Imaging: A Reader Preference Study.

This reader preference study compared low-dose chest imaging quality between photon-counting detector CT (PCD-CT) and conventional energy-integrating detector CT (EID-CT) in asbestos-exposed participants from the Western Australian Asbestos Review Program, using paired scans at reduced dose. It found that radiologists’ relative preferences and image-quality assessments favored one modality over the other (PCD-CT versus EID-CT) under the paired low-dose conditions. The significance is that it directly informs clinical acceptability and perceived image quality when transitioning from EID-CT to photon-counting CT for low-dose chest imaging.

Milne B, Soon J, Srigandan S et al. · Journal of medical imaging and radiation oncology · (2026) · View on PubMed ↗

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Radiotherapy Planning and CT-Derived Quantitative Biomarkers

Reduction of CT number location dependency using photon-counting detector CT and virtual monoenergetic imaging.

This work compared photon-counting detector CT (PCD-CT) versus energy-integrating detector CT (EID-CT) for reducing CT-number location dependency relevant to radiotherapy planning across tissue types, imaging modes, and patient sizes using a multi-energy CT phantom (Gammex) with tissue inserts (cortical bone, liver, lung, adipose) and a larger phantom configuration with Superflab. PCD-CT reduced CT-number location dependence relative to EID-CT across the tested conditions by leveraging energy-selective measurements and virtual monoenergetic imaging. The findings indicate that PCD-CT could improve radiotherapy dose calculations and robustness by making CT-derived electron density/stoichiometry more spatially consistent.

Sadeghian M, Swicklik JR, McCollough CH et al. · Physics in medicine and biology · (2026) · View on PubMed ↗

Photon-counting CT for radiotherapy: Qualitative assessment of potential clinical value by semi-structured expert interviews.

This qualitative study investigated where photon-counting CT (PCCT) could add clinical value in radiotherapy by interviewing expert teams across eight treatment sites (radiation oncologists and a site-experienced radiologist). The key finding was that PCCT’s intrinsic spectral information and high-resolution imaging were perceived as most beneficial for specific radiotherapy workflows and anatomical targets, varying by treatment site. This supports prioritizing PCCT implementation toward the radiotherapy indications most likely to improve planning, visualization, and operational efficiency.

Kroes-Kobus T, Rossi L, Nuyttens JJME et al. · Clinical and translational radiation oncology · (2026) · View on PubMed ↗

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Coronary CT Angiography in Calcified Disease and Plaque Quantification

Lumen imaging in calcified coronary arteries using high-resolution Gd-enhanced color K-edge imaging with spectral photon-counting CT: a phantom study.

The study evaluated Gd-enhanced coronary CT lumen assessment in an anthropomorphic phantom containing a hollow coronary artery with calcifications of varying hydroxyapatite density using a clinical spectral photon-counting CT prototype with high-resolution color Gd K-edge imaging. Lumen visibility improved by exploiting the spectral separation between gadolinium and calcium, addressing the similar attenuation problem that limits conventional iodine-based CCTA in calcified arteries. This phantom evidence supports K-edge–based photon-counting CT for more reliable coronary lumen evaluation in heavily calcified disease, potentially improving CCTA diagnostic performance and treatment planning.

Dobrolinska MM, van der Werf N, Greuter M et al. · European radiology experimental · (2026) · View on PubMed ↗

Ultra-high resolution photon-counting detector coronary CT angiography: diagnostic accuracy in patients with high Agatston scores.

This single-center diagnostic accuracy study evaluated ultra-high resolution (UHR) photon-counting detector coronary CT angiography in patients with very high coronary calcium burden (Agatston score > 600), using invasive coronary angiography (ICA) as the reference. It found that UHR PCD-CT improved visualization by reducing calcium blooming artifacts compared with conventional CCTA, leading to better performance for detecting coronary stenoses. The clinical significance is that UHR PCD-CT may provide more reliable noninvasive assessment of coronary artery disease in patients with severe calcification.

Demmert TT, Klambauer K, Moser LJ et al. · European radiology · (2026) · View on PubMed ↗

Deep Learning-based Automated Coronary Plaque Quantification: First Demonstration With Ultra-high Resolution Photon-counting Detector CT at Different Temporal Resolutions.

The study evaluated a deep learning–based automated coronary plaque quantification tool with automatic case preparation in 45 patients undergoing ultra-high resolution (UHR) photon-counting detector CT coronary angiography (CCTA), comparing dual-source reconstructions at 66 ms temporal resolution versus simulated single-source reconstructions at 125 ms. It found the tool was feasible and reproducible for plaque quantification and that temporal resolution influenced plaque quantification results. This is significant because it informs how UHR PCCT reconstruction timing affects automated coronary plaque measurements, supporting more consistent quantitative CCTA in clinical practice.

Klambauer K, Burger SD, Demmert TT et al. · Investigative radiology · (2026) · View on PubMed ↗

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Pulmonary CT Angiography and Pulmonary Embolism/Distal Vessels

Increasing pulmonary artery visibility and diagnostic confidence with ultra-high resolution photon-counting detector CT pulmonary angiography.

This retrospective single-center study compared ultra-high-resolution photon-counting detector CT pulmonary angiography (UHR-PCD-CTPA) at two image quality indices (IQ50 and IQ25) with dual-energy energy-integrating detector CTPA in 227 analyzed examinations (after exclusions) to assess pulmonary artery visibility and diagnostic confidence. UHR-PCD-CTPA improved peripheral pulmonary artery visibility and increased radiologist-rated image quality/diagnostic confidence compared with dual-energy EID-CTPA, with performance varying by IQ setting. Clinically, this suggests that UHR PCD-CTPA may enhance detection of distal pulmonary emboli while maintaining diagnostic reliability, potentially enabling lower-dose or more confident CTPA interpretation.

Pannenbecker P, Rüth C, Grunz JP et al. · European radiology · (2026) · View on PubMed ↗

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Other Thoracic Imaging (Nodules, Prostheses, Asbestos Cohorts)

Impact of Spatial Resolution on CT Imaging of Middle Ear Prostheses: Comparison of Photon-Counting and Energy-Integrating Detectors.

This study assessed how spatial resolution affects visualization of submillimeter middle ear prostheses by comparing photon-counting detector CT (PCD-CT), energy-integrating detector CT (EID-CT), and EID-CT with attenuating comb filters using a head phantom containing 21 middle ear prostheses. Higher spatial resolution with PCD-CT improved prosthesis visualization compared with standard EID-CT approaches, and comb-filter strategies partially mitigated resolution limitations. The results support selecting PCD-CT (and potentially resolution-enhancing reconstruction/filtering) to improve imaging of tiny middle ear implants critical for postoperative management.

Sadeghian M, Benson JC, Farnsworth PJ et al. · AJNR. American journal of neuroradiology · (2026) · View on PubMed ↗

Diagnostic Significance of Phase-Resolved Functional Lung Low-field Magnetic Resonance Imaging in Comparison to Photon-Counting CT and Pulmonary Function Tests in Connective Tissue Disease-associated Interstitial Lung Diseases.

This prospective single-center study evaluated phase-resolved functional lung (PREFUL) low-field MRI in connective tissue disease-associated interstitial lung disease (CTD-ILD) and compared it with photon-counting CT (PCCT) and pulmonary function tests (PFTs). It found that PREFUL performance correlated with disease severity/extent metrics derived from PCCT and with physiologic measures from PFTs, suggesting complementary diagnostic information. The significance is that PREFUL may reduce reliance on repeated CT in CTD-ILD by offering an alternative imaging pathway with lower radiation exposure.

Muecke R, Shahzadi I, Assmann G et al. · Journal of thoracic imaging · (2026) · View on PubMed ↗

First-generation Photon-counting Computed Tomography Angiography Versus Third-generation Dual-energy Computed Tomography Angiography for Peripheral Artery Disease Imaging.

This retrospective study compared first-generation photon-counting CT angiography (PCCT) with third-generation dual-energy CT angiography (DECT) for peripheral artery disease (PAD) imaging, using digital subtraction angiography (DSA) as the reference standard for stenosis grading. It found that PCCT and DECT differed in objective performance and subjective image quality across reconstructed virtual monoenergetic images (40–60 keV), with measurable differences in noise and signal-to-noise ratio (SNR). The significance is that it provides early comparative evidence for selecting PCCT versus DECT strategies for PAD CTA, potentially improving stenosis assessment accuracy and image quality.

Ghibes P, Partovi S, Wrazidlo R et al. · Investigative radiology · (2026) · View on PubMed ↗

Comparing the detectability of pulmonary nodules on two ultra-high resolution CT scanners: a preliminary phantom study.

The study used a preliminary phantom design to compare detectability of pulmonary nodules between an ultra-high-resolution CT scanner with energy-integrating detectors and a photon-counting CT (PCCT) system in UHR mode. It found that task-based metrics derived from noise power spectrum and transfer function (including detectability indices d’) differed between the two scanner types at matched low-dose settings (7.5/2.5/0.4 mGy), affecting modeled nodule detectability. This is significant because it provides early, physics-based evidence on whether PCCT improves nodule detectability under UHR chest protocols before larger clinical studies.

Greffier J, Salvat C, Pastor M et al. · European radiology · (2026) · View on PubMed ↗

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Neuroradiology and Intracranial CSF Leak Disorders

Recent Updates to Diagnosis and Treatment of Spontaneous Intracranial Hypotension.

This focused review studied spontaneous intracranial hypotension in patients with spinal cerebrospinal fluid (CSF) leaks, emphasizing updated mechanisms, diagnostic imaging for leak localization, and treatment strategies. It found that modern classification of causative spinal CSF leak types and improved imaging approaches have substantially refined diagnosis and management beyond earlier decades. Clinically, these updates support more accurate localization and more targeted therapy for orthostatic headache and other manifestations of CSF hypovolemia.

Madhavan AA, Yoon ES, Chazen JL · Korean journal of radiology · (2026) · View on PubMed ↗

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Head/Neck CT Applications (Parathyroid and Middle Ear)

4D Parathyroid CT Using Photon-Counting Detector CT.

The article describes a 4D parathyroid CT protocol implemented on photon-counting detector CT for patients with hyperparathyroidism undergoing multiphase imaging to detect parathyroid adenomas. The key premise is that photon-counting CT’s increased spatial and contrast resolution can better distinguish parathyroid adenomas from thyroid and adjacent central-compartment soft tissue density patterns. If validated clinically, this protocol could improve adenoma localization and surgical planning accuracy compared with traditional energy-integrating 4D parathyroid CT.

Mark IT, Shanblatt ER, El Sadaney AO et al. · AJNR. American journal of neuroradiology · (2026) · View on PubMed ↗

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Musculoskeletal Imaging and Pediatric Bone Lesions

Interrater agreement for characterization of capitellar osteochondritis dissecans using photon-counting computed tomography technology.

This study evaluated interrater agreement for characterizing capitellar osteochondritis dissecans (COCD) lesion features in children using photon-counting CT (PCCT) compared with conventional CT by having multiple experienced clinicians and musculoskeletal radiologists independently assess anonymized PCCT and conventional scans. PCCT demonstrated improved or comparable reliability (quantified via intraclass correlation coefficients) for lesion characterization relative to conventional CT, supporting more consistent imaging-based assessment. The significance is that higher-resolution, dose-reducing PCCT may strengthen surgical decision-making by improving agreement on COCD imaging findings.

Steenbeek ED, van der Laan T, Booij R et al. · JSES international · (2026) · View on PubMed ↗

[Primary malignant bone tumours-part 1].

This radiology review studied primary malignant bone tumors, focusing on children and adolescents where osteosarcoma and Ewing sarcoma are the most frequent sarcomas. It found that early recognition of radiologic signs (e.g., periosteal reactions) using a broad diagnostic toolkit including radiography, MRI, CT, and ultrasonography is crucial because these tumors are highly malignant with poor prognosis, especially for metastatic Ewing sarcoma. Scientifically and clinically, the article highlights how familiarity with early imaging patterns can improve suspicion and downstream diagnostic accuracy.

Grieser T · Radiologie (Heidelberg, Germany) · (2026) · View on PubMed ↗

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Cardiac Tissue Characterization (Iron/Fat, Atrial Anatomy for Ablation)

Quantification of myocardial iron and fat-an experimental study with photon-counting detector CT.

This experimental study evaluated photon-counting detector CT (PCD-CT) for quantifying myocardial iron and fat using porcine myocardium phantoms with iron citrate (0–20 mg Fe g−1) and matched fat conditions (5% fat vs no-fat). It found that attenuation increased linearly with iron concentration on virtual monoenergetic images and that a re-parameterized 3-material decomposition could separate iron and fat from myocardium. The results suggest PCD-CT is feasible for noninvasive myocardial iron/fat quantification, which could improve assessment of cardiac iron overload and related tissue composition.

Maintz PN, Demmert TT, Flohr T et al. · The British journal of radiology · (2026) · View on PubMed ↗

Simulation of peri-mitral ablation lines using photon-counting computed tomography-based mapping of atrial wall thickness and epicardial adipose tissue.

This prospective simulation study in 198 patients used photon-counting CT (PCCT) to map left atrial wall thickness and epicardial adipose tissue, then simulated peri-mitral catheter ablation lines. The key finding was that the simulated ablation line profiles differed in their relationship to myocardial thickness and epicardial adipose tissue, enabling identification of a more favorable line profile for durable lesion formation. Clinically, this PCCT-based planning approach could help optimize peri-mitral flutter ablation strategies by tailoring lesion geometry to patient-specific atrial anatomy.

Bahlke F, Siller M, Grosshauser M et al. · Heart rhythm · (2026) · View on PubMed ↗

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Hepatic Imaging Biomarkers (Fat, ECV, Portal Hypertension)

Agreement of VNC and Spectral Photon-Counting CT in the Assessment of Normal to Minimal Hepatic Fat in Comparison with MRI.

This retrospective clinical study assessed agreement between virtual non-contrast (VNC) and spectral photon-counting CT (PCD-CT) methods for quantifying normal-to-minimal hepatic fat, using MRI-derived fat fraction (FF) as the reference standard. It found that PCD-CT-based reconstructions and spectral post-processing showed measurable concordance with MRI FF for low liver fat levels. Scientifically, this supports PCD-CT as a potential radiation-efficient alternative for hepatic fat quantification in patients undergoing abdominal imaging.

Klemm D, Russe MF, Reisert M et al. · Academic radiology · (2026) · View on PubMed ↗

Photon-counting CT-derived hepatic extracellular volume quantification for noninvasive risk stratification of clinically significant portal hypertension (CSPH): a prospective cohort study.

This prospective cohort study investigated whether photon-counting CT (PCCT)-derived hepatic extracellular volume (ECV) can noninvasively detect or exclude clinically significant portal hypertension (CSPH) in 113 participants with compensated advanced chronic liver disease. It found that hepatic ECV calculated from delayed-phase contrast-enhanced PCCT (5 minutes post-contrast) performed as an imaging biomarker aligned with reference standards including transient elastography liver stiffness measurements and histological fibrosis grading. Clinically, PCCT-derived hepatic ECV could improve noninvasive risk stratification for CSPH, potentially reducing the need for invasive assessment.

Dell T, Tischler V, Zocholl D et al. · European radiology · (2026) · View on PubMed ↗

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Proton Therapy Range Uncertainty and Stopping Power Estimation

Proton therapy range uncertainty reduction using vendor-agnostic tissue characterization on a virtual photon-counting CT head scan.

This computational study proposed vendor-agnostic tissue characterization using a virtual photon-counting CT head scan to reduce proton therapy range uncertainty by improving stopping power estimation from spectral data. The approach validated in complex human head geometry showed that virtual PCCT–based stopping power ratios can reduce range uncertainty compared with conventional assumptions used in proton planning. Scientifically, it supports using photon-counting spectral information (even via virtual simulators) to make proton range predictions more accurate in realistic anatomy.

Vrbaski S, Stanic G, Molinelli S et al. · Medical physics · (2026) · View on PubMed ↗

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Computational/Mechanistic Modeling for Respiratory Drug Response

Subject-Specific Whole-Lung CFPD Coupled with PBPK/PD to Predict Inhaled Bronchodilator Response in Asthmatic and Healthy Subjects.

The study developed and tested a coupled computational fluid and particle dynamics (CFPD) with physiologically-based pharmacokinetic/pharmacodynamic (PBPK/PD) framework to predict inhaled bronchodilator response (ΔFEV1) using subject-specific CT-derived airway trees and airflow distributions in six asthmatic and ten healthy subjects. For a 400 μg albuterol dose delivered via metered dose inhaler (MDI) and dry powder inhaler (DPI), the model predicted subject-specific regional lung exposure and the resulting clinical effect on ΔFEV1. This is significant because it provides a CT-informed, mechanistic way to forecast bronchodilator performance and could support personalized inhaler therapy optimization.

Rajaraman PK, Zhang X, Comellas AP et al. · Journal of aerosol science · (2026) · View on PubMed ↗

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Clinical Reviews, SWOT/Qualitative Assessments, and Implementation Roadmaps

Optimizing Screening of Hepatocellular Carcinoma with Computed Tomography and MR Imaging: Emerging Research, Updated Guidelines, and New Technologies.

This narrative review summarized emerging research, updated guidelines, and new technologies for hepatocellular carcinoma (HCC) screening using CT and MR imaging, emphasizing abbreviated MR protocols and advances in CT including dual-energy and photon-counting CT. The key message is that CT/MR strategies can complement or improve upon ultrasound in populations where ultrasound sensitivity is limited, with photon-counting CT highlighted as a promising next-generation technique. Clinically, the review frames how newer spectral CT approaches may improve detection performance and workflow for HCC screening.

An JY, Dane BR, Marks RM · Radiologic clinics of North America · (2026) · View on PubMed ↗

Photon-counting CT in neuroradiology: a comprehensive SWOT analysis.

This SWOT analysis studied photon-counting detector CT (PCD-CT) in neuroradiology, comparing its capabilities to conventional energy-integrating detector CT. It found that PCD-CT’s advantages—higher contrast-to-noise ratio, reduced metal artifacts, improved spatial resolution, and potential reductions in radiation and iodine dose—are major strengths, while limitations and implementation challenges represent key weaknesses. The significance is that the review frames where PCD-CT is most likely to impact neuroradiologic practice and where further evidence and technical development are needed.

Martín-Noguerol T, Santos-Armentia E, Zhu D et al. · European radiology · (2026) · View on PubMed ↗

Japanese Radiology 2025 Updates.

This review summarized recent Japanese advances in diagnostic imaging, focusing on technologies such as upright multidetector CT (MDCT), AI computer-aided synthesized mammography, automated breast ultrasound (ABUS), and abbreviated MRI protocols. It found that these innovations are reshaping clinical workflows and improving diagnostic capabilities across radiology subspecialties. The significance is that it provides a consolidated, Japan-focused roadmap of emerging imaging techniques that may accelerate adoption of posture-aware CT and AI-augmented breast and MRI workflows.

Iima M, Saida T, Yamada Y et al. · Canadian Association of Radiologists journal = Journal l’Association canadienne des radiologistes · (2026) · View on PubMed ↗

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Generated automatically on May 06, 2026. Covers PubMed articles published April 29, 2026 – May 06, 2026. Summaries are AI-generated; always consult the original publication for clinical or research decisions.