What’s New in Photon Counting CT?

July 21, 2026 · 7 articles · 7 research themes · covering July 14, 2026 – July 21, 2026

Overview

Across these studies, photon-counting detector CT (PCD/PCCT) emerges as a platform for both quantitative tissue characterization and clinically actionable imaging improvements. Several works leverage spectral information—either through virtual monoenergetic/virtual non-contrast reconstructions for liver attenuation and steatosis quantification, or through physics-driven material decomposition to estimate proton stopping power ratio and range for radiotherapy planning. Complementing this, a scanner-specific spectral modeling approach estimates voxelwise effective atomic number and electron density, aiming to move beyond conventional CT attenuation toward more fundamental, tissue-relevant biomarkers.

On the clinical imaging side, photon-counting CT shows promise for dose-efficient routine abdominal imaging and for high-contrast vascular applications. A prospective comparison of PCCT versus energy-integrating CT demonstrates significant radiation dose reduction while maintaining objective and subjective image quality. In parallel, photon-counting CT angiography is shown to be feasible for detecting spinal arteriovenous fistulas, exploiting improved spatial resolution and contrast-to-noise ratio.

Finally, the digest includes a non-CT modality innovation: an AI-assisted, inversion recovery prepared IR-UTE approach for faster, radiation-free bone MRI of the knee. Together, the articles highlight a broader trend toward faster, safer imaging—either by reducing CT dose, enabling radiation-free alternatives, or extracting more information per scan via spectral reconstruction and advanced reconstruction/estimation methods.

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Photon-Counting CT Spectral Quantification (Zeff/ρe)

Power law spectral photon-counting CT for quantitative effective atomic number and electron density imaging.

This study developed and evaluated a scanner-specific power-law spectral photon-counting CT method to estimate voxelwise effective atomic number (Zeff) and electron density (ρe) on a commercial spectral photon-counting CT system. The approach modeled the energy-dependent attenuation coefficient as a power-law sum of photoelectric, Compton, and empirical correction terms, fitting coefficients to NIST cross sections (Z=6–21) over 7–115 keV and validating using a QRM spectral-CT phantom with soft-tissue-equivalent, hydroxyapatite, and iodine inserts. If robust across scanners and heterogeneous tissues, this enables quantitative tissue characterization beyond conventional CT attenuation.

Alzaabi M, Behouch A, Tariq B et al. · Physics in medicine and biology · (2026) · View on PubMed ↗ · Free PDF ↗

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Photon-Counting CT for Proton Therapy Planning (SPR/Range)

Optimal dimensionality and fundamental limits of proton stopping power estimation with photon-counting CT material decomposition.

This physics study investigated the optimal dimensionality and fundamental limits of proton stopping power ratio (SPR) and range estimation from photon-counting CT (PCCT) data using material decomposition. Using eigentissue decomposition for CT-based material decomposition, the work evaluated how increasing the number of energy measurements and decomposition dimensionality affects SPR/range estimation feasibility for proton therapy planning. The results inform whether PCCT’s spectral information can reduce range uncertainty and treatment margins in proton radiotherapy.

Larsson K, Näsmark T, Andersson J et al. · Physics in medicine and biology · (2026) · View on PubMed ↗ · Free PDF ↗

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Virtual Non-Contrast / Monoenergetic Imaging from PCD-CT

Single-Phase Surrogate for True Non-Contrast Liver CT Using 190-keV Monoenergetic Imaging on Photon-Counting CT: Implications for Hepatic Steatosis Assessment.

This retrospective study evaluated whether 190-keV virtual monoenergetic imaging (VMI) reconstructed from photon-counting detector CT (PCD-CT) equilibrium-phase scans can act as a surrogate for true non-contrast (TNC) CT in 49 patients undergoing abdominal PCD-CT and MRI-proton density fat fraction (PDFF) within 2 months. Liver attenuation agreement between TNC and 190-keV VMI (and comparison with virtual non-contrast, VNC) was assessed using Pearson correlation and Bland–Altman analysis across four hepatic segments. If validated, 190-keV VMI from PCD-CT could enable more accurate hepatic steatosis quantification without requiring separate true non-contrast acquisitions.

Ohtani T, Shimada M, Nishiyama K et al. · Academic radiology · (2026) · View on PubMed ↗

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Dose Reduction and Image Quality in Photon-Counting vs Conventional CT

Photon-counting CT vs. energy-integrating detector CT: image quality and radiation dose in multi-phase abdominopelvic imaging.

In a prospective study of 94 adults undergoing multi-phase abdominopelvic CT, the authors compared photon-counting detector CT (PCCT) with energy-integrating detector CT (EID-CT) for radiation dose and image quality. PCCT significantly reduced radiation exposure (CTDIvol, DLP, and scan-length normalized DLP) while objective metrics (hepatic noise, SNR, CNR) and subjective radiologist Likert scores were used to evaluate image quality. This supports PCCT as a dose-reducing alternative to EID-CT for routine multi-phase abdominal imaging while maintaining diagnostic image quality.

Huang YF, Yang JF, Zhao L et al. · Radiation protection dosimetry · (2026) · View on PubMed ↗

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Photon-Counting CT Angiography (Vascular Lesion Detection)

Utility of Photon Counting Detector CT Angiography for Detecting Spinal Arteriovenous Fistulas.

This retrospective two-institution case series assessed the utility of photon-counting detector CT angiography for detecting spinal arteriovenous fistulas in eight patients. Leveraging photon-counting CT’s higher spatial resolution, inherent spectral sensitivity, and improved contrast-to-noise ratio, the study demonstrated feasibility for identifying and characterizing these vascular lesions. Clinically, this could expand noninvasive, high-contrast spinal vascular imaging options for a treatable cause of myelopathy.

Madhavan AA, Bathla G, Hauck EF et al. · AJNR. American journal of neuroradiology · (2026) · View on PubMed ↗ · Free PDF ↗

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Spectral CT for Musculoskeletal Oncology/Pathology (Myeloma)

Ultra-High-Resolution Dual-Source Photon-Counting CT for Expanded Characterization of Pathophysiological Imaging Patterns in Multiple Myeloma.

This retrospective study of 84 patients with multiple myeloma (53 therapy-naïve and 31 with precursor conditions) used dual-source photon-counting CT (DS-PCCT) to characterize axial and appendicular skeletal manifestations at initial diagnosis. By exploiting attenuation characteristics in low-keV virtual monoenergetic images (VMI), the authors expanded pattern characterization of soft tissue and fat contributions across the skeleton. The approach may improve whole-body assessment of myeloma pathophysiology by combining spectral information with ultra-high spatial resolution.

Heidemeier A, Huflage H, Rasche L et al. · Investigative radiology · (2026) · View on PubMed ↗ · Free PDF ↗

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AI-Accelerated Radiation-Free Bone MRI (Knee)

Fast MRI of bones in the knee - An AI-driven reconstruction approach for adiabatic inversion recovery prepared ultra-short echo time sequences.

This feasibility study aimed to accelerate radiation-free bone MRI of the knee using inversion recovery prepared ultra-short echo time (IR-UTE) sequences reconstructed from undersampled data with an AI-driven approach. Using a denoising convolutional neural network (DnCNN) trained on data from eight healthy subjects and reconstruction with conjugate gradient sensitivity encoding (CG-SENSE), the method targeted faster 3D imaging of osseous tissue. If successful, it could reduce MRI acquisition time for bone imaging while preserving image quality.

Nunn PH, Huflage H, Grunz JP et al. · Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB) · (2026) · View on PubMed ↗ · Free PDF ↗

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Generated automatically on July 21, 2026. Covers PubMed articles published July 14, 2026 – July 21, 2026. Summaries are AI-generated; always consult the original publication for clinical or research decisions.