Malignant tumors remain a major global public health challenge, and the limitations of conventional energy-integrating detector computed tomography (EID-CT) in spatial resolution, early lesion detection, and quantitative analysis continue to constrain precise diagnosis and treatment of tumors. Photon-counting computed tomography (PCCT), an emerging CT technology, has shown promising potential in tumor imaging. In this study, the literature on PCCT in oncologic imaging was searched and screened. Existing reviews lack an integrated analysis of comparative evaluation and technological innovation for oncological applications, with insufficient large-sample clinical evidence and discussion of multimodal imaging-AI integration. Regarding these issues, the included literature was classified and analyzed based on comparative evaluation research and technological innovation research. First, the medical background and theoretical basis of PCCT in tumor imaging are introduced. Subsequently, recent relevant studies are reviewed from the perspectives of comparative evaluation and technological innovation. Finally, the current research status and development trends in this field are analyzed and discussed. PCCT achieves high-resolution, low-dose, spectral tumor imaging for lesion detection and tissue characterization. Therefore, PCCT may support precise imaging diagnosis and personalized tumor treatment.
Accurate brain tumor segmentation is critical for diagnosis and treatment planning. However, U-Net-based models struggle with complex tumor morphologies and fine boundaries. This paper proposes a novel brain tumor segmentation network, termed GFC-Unet. Built upon the 3D U-Net architecture, this network introduces three core modules: (1) the Multi-modal Feature Recalibration (MFR) module; (2) the Gated Feature Convolution (GFC) module; and (3) the Feature Uncertainty Evaluation (FUE) module. Experimental results on the Brain Tumor Segmentation (BraTS) 2020 and 2021 datasets demonstrate that GFC-Unet achieves Dice coefficients of 92.82%, 87.74%, and 87.47% on BraTS2020, and 92.61%, 87.49%, and 86.89% on BraTS2021 for whole tumor (WT), tumor core (TC), and enhancing tumor (ET), respectively. Ablation studies validate the effectiveness of each module. Furthermore, extended experiments on the Data Science Bowl (DSB) 2018 cell nucleus segmentation and International Skin Imaging Collaboration (ISIC) 2018 skin lesion segmentation tasks demonstrate the strong generalization capability. By integrating these modules, GFC-Unet improves segmentation accuracy and boundary delineation, demonstrating promise for supporting clinical decision-making.
Mobile X-ray examinations in neonatal intensive care units (NICUs) are essential for the critically ill neonates. However, scattered radiation generated during imaging can lead to unnecessary radiation exposure for adjacent neonates and healthcare workers. Conventional mobile shielding devices are often challenging to implement effectively in NICU environments due to limited space and workflow constraints. Consequently, this study developed a foldable lead curtain that can be attached to a mobile X-ray unit and evaluated experimental measurements and Monte Carlo simulations. The lead curtain features a foldable acrylic panel structure that contains 0.15 mmPb shielding material and is designed for attachment to a mobile X-ray unit. Shielding efficiency experiments showed that the lead curtain reduced scattered radiation by 91.1% at a distance of 50 cm when positioned directly in the scatter path. At distances of 100 cm and 150 cm, the shielded readings fell below the detection limit of the ionization chamber dosimeter. Notably, significant dose reductions were observed even under the relatively low shielding condition of 0.15 mmPb. These findings suggest that the proposed attachable foldable lead curtain may serve as a practical auxiliary radiation protection device for reducing scattered radiation exposure to adjacent neonates, which often face substantial spatial limitations.
Background: Calcium blooming in coronary CT angiography (CCTA) enlarges calcified plaques, obscures the coronary lumen, and complicates stenosis assessment. Objective: To develop an efficient restoration method that suppresses blooming while preserving calcium and recovering adjacent lumen structure. Methods: We propose Short-Trajectory Artifact-Reversal (STAR) Diffusion, which progressively transforms a blooming-corrupted patch toward a debloomed target. Soft Annular Boundary Attention (SABA) reduces attention leakage from the blooming-prone annulus into the calcium core. Results: On 232 held-out synthetic 3D test cases, each sampled from a distinct anatomical location and unique plaque, background, calcium concentration, and exposure/noise configuration, STAR Diffusion achieved Dice 0.9248, Core RMSE 134.99 HU, and Annulus RMSE 90.05 HU. Metrics were computed after slice-wise inference and volumetric reassembly, with one matched case-level measurement per test volume for direct comparison across methods. The method improved calcium-region agreement and annular error relative to classical, GAN-based, and latent diffusion baselines, while ablations showed complementary contributions from spatial-prior conditioning and SABA. STAR Diffusion also reduced inference time compared with long-trajectory latent diffusion. Conclusions: In synthetic paired-data experiments, short-trajectory, spatially guided diffusion with boundary-aware attention reduced blooming while preserving plaque morphology and apparent lumen visibility. Clinical examples showed qualitatively similar behavior across plaque shapes and backgrounds.
The development of high-atomic-number (high-Z) nanomaterials as computed tomography (CT) contrast agents has attracted considerable interest because of their strong X-ray attenuation. In this study, hyaluronic acid (HA)-functionalized bismuth sulfide nanoparticles (Bi2S3@BSA-HA) were synthesized and characterized, and their CT imaging performance was evaluated over a tube-voltage range of 80-130 kVp. CT attenuation was assessed as a function of Bi concentration and tube voltage and compared with non-functionalized Bi2S3@BSA nanoparticles and the clinical iodinated contrast agent Omnipaque. Contrast-to-noise ratio (CNR), cytocompatibility, and in vitro cellular CT imaging were also evaluated. Bi2S3@BSA-HA exhibited significantly higher CT attenuation than both Bi2S3@BSA and Omnipaque, reaching 146.8 +/- 6.9 HU at 1.5 mg Bi mL(-1) and 80 kVp. CT attenuation increased linearly with Bi concentration (R-2 > 0.93) and decreased with increasing tube voltage. The HA-functionalized nanoparticles consistently exhibited higher CNR values across all investigated tube voltages. MTT assays demonstrated low cytotoxicity, with cell viability exceeding 90% after 24 h. In vitro cellular CT imaging showed higher CT numbers and CNR in HT-29 cells incubated with Bi2S3@BSA-HA than with Bi2S3@BSA. These findings demonstrate improved in vitro CT imaging performance with good cytocompatibility under the investigated conditions.
