This study evaluated whether a static magnetic field can modulate the electron-associated component of dose during diagnostic electromagnetic photon beam exposures. Doses were measured with a solid-state dosimeter at 60–110 kVp (10-kVp steps) on an X-ray radiation gene rator operated at 200 mA, 100 cm source-to-detector distance, 1.0 s, and 20 × 20 cm field. For each kVp, 20 repeated measurements were acquired under two conditions: no field versus a transverse ~0.5 T field generated by Nd magnets; output reproducibility was verified (all CV ≤ 0.05). With the field applied, doses were consistently but slightly lower at 60–90 kVp (all two- sided P > 0.05). Statistically significant reductions appeared at higher kVp: 100 kVp, 21.325 ± 0.155 vs 21.245 ± 0.076 mGy (P = 0.048); 110 kVp, 24.970 ± 0.108 vs 24.910 ± 0.072 mGy (P = 0.047). These findings support the feasibility of magnetic-field–induced dose modulation under diagnostic-energy conditions.

Temporal Interference Stimulation (TIS) advancement is hindered by technical limitations. This study aims to overcome these by developing a precision system and experimentally validating its core principle, focal point steering via current ratio control, through cross-validation in phantom, ex vivo, and computational models. We performed invasive experiments applying 108 and 100 Hz for an 8 Hz difference at 1:1, 2:1, and 1:2 ratios, maintaining 2.1 mA total current, in phantoms, ex vivo mouse brain, and muscle. Results consistently matched TIS theory: the 8 Hz envelope peak was centered at 1:1 and predictably shifted toward the weaker current side at 2:1/1:2 ratios. High concordance between experiments and simulations confirmed steering was maintained despite different tissue impedances. This integrative validation confirms TIS steering feasibility and provides a validated platform for future personalized stimulation.

This study evaluates radiation exposure risks associated with baggage jamming in X-ray security inspection systems and proposes a new push-type shielding door mechanism to mitigate such exposure. Using the Monte Carlo code MCNPX v2.7 and the HDRK-Man computational phantom, simulations were conducted to estimate leakage and operator dose rates under various obstruction scenarios. The results demonstrated that when the lead curtain was fully open due to baggage jam, operator exposure reached up to 22.69 μSv/hr, exceeding public dose limits. Implementation of the newly designed shielding door reduced this dose to 0.06 μSv/hr, achieving a 99.7% reduction in exposure. The proposed system not only ensures compliance with domestic radiation safety regulations but also improves operational efficiency and inspection stability.

Myocardial extracellular volume (ECV) is an important parameter for assessing the pathophysiology of cardiomyopathy, and cardiac magnetic resonance imaging (CMR) is established as the standard technique for its measurement. However, CMR has several clinical limitations, creating a need for alternative imaging modalities. Cardiac computed tomography (CT) has emerged as a potential alternative. The primary aim of this study was to directly compare the accuracy and agreement of myocardial ECV measured by cardiac CT (CT-ECV) and by CMR (MRI-ECV) in the same patient cohort. In this retrospective study, 44 patients were included, all of whom underwent both cardiac CT and CMR. Statistical analyses, including paired t-tests and Pearson correlation, were performed to compare ECV values obtained by the two techniques. In the overall cohort, the mean MRI-ECV was 26.27%, and the mean CT-ECV was 26.57%. The mean difference between the two modalities was not statistically significant (p = 0.279). A strong positive correlation was observed between CT-ECV and MRI-ECV values (r = 0.776). CT-ECV demonstrated a high degree of correlation and agreement with the CMR reference standard, suggesting that CT-ECV may serve as a reliable, accurate, and clinically practical alternative for myocardial tissue characterization in patients with cardiomyopathy.

Low-dose computed tomography (CT) is essential for minimizing patient radiation exposure; however, increased noise often leads to image degradation and may adversely affect diagnostic accuracy. In this study, we propose an optimized CT image restoration method that integrates wavelet transform with the U-Net architecture. The proposed approach decomposes the input image into low- and high-frequency components, selectively removes noise from the high-frequency bands, and reconstructs the image while preserving structural information in the low-frequency bands. The reconstructed components are subsequently refined through the U-Net for final denoising. Performance was quantitatively evaluated using PSNR and SSIM, showing improvements in the average PSNR by 10.3% and average SSIM by 14.7%, respectively, compared to the conventional U-Net. These results demonstrate that the wavelet-based U-Net model offers superior denoising performance while maintaining image resolution and anatomical structure, suggesting it as an effective approach for improving the quality of low-dose CT images.

This study investigated the effects of a multimodal intervention on spatiotemporal gait parameters and mobility outcomes in patients with subacute stroke. Using a three-phase, single-case design, two participants (6–12 months after onset) received robot-assisted gait training with Angel Legs M20 and 1 Hz low frequency repetitive transcranial magnetic stimulation to the contralesional primary motor cortex as a priming procedure, with Participant 2 additionally receiving familiar place-based visual cues. Cadence, gait speed, and step length were assessed alongside the Berg Balance Scale, Timed Up and Go test, and Functional Ambulation Category. Incorporation of familiar place-based visual cues was associated with improved cadence (42.33 ± 0.58 to 65.00 ± 0.00 steps/min; Δ = +53.5%) and gait speed (0.353 ± 0.006 to 0.540 ± 0.000 m/s; Δ = +52.9%), without altering the step length (Δ = −0.6%). These enhancements were accompanied by modest but clinically meaningful improvements in balance and functional mobility. These findings support further research into its applicability for community ambulation.

A detector utilizing a block scintillator and a semiconductor light sensor was designed for small animal positron emission tomography/magnetic resonance imaging (PET/MRI) applications that achieves high resolution and sensitivity without signal distortion in a magnetic field. The goal was to achieve high sensitivity by using a block scintillator rather than a pixelated scintillator, and high resolution by applying a maximum likelihood position estimation (MLPE). A DETECT2000 simulation was performed to evaluate the performance of the designed detector. Gamma-ray events, where the scintillator and gamma-rays interact, were generated at 1 mm intervals in all directions within the scintillator, and signals were collected by the light sensor. A look-up table (LUT) was created based on the collected signals, and the measurement accuracy of the gamma-ray interaction location was evaluated using the LUT and MLPE. The results showed an excellent measurement accuracy of approximately 85.7% on average. It is considered that this detector can achieve excellent sensitivity and resolution when used in small animal PET/MRI.

C-arm fluoroscopy provides essential real-time imaging for various interventional procedures but entails radiation exposure risks for both patients and medical staff. Conventional lead and lead-free shields offer high attenuation yet remain limited in clinical use due to weight, image artifacts, and procedural constraints. This study evaluated a lead-free composite shield composed of tungsten, tungsten carbide, bismuth, aluminum, and polyurethane, focusing on dose reduction, scatter shielding performance, image quality, and interactions with Automatic Brightness Control (ABC) in a C-arm environment. PHITS-based Monte Carlo simulations demonstrated strong attenuation in the low-to-mid energy range across 60–120 kVp. Experimental measurements showed attenuation rates of 59.6–70.8% (no filter), 45.4–55.4% (Al 2.5 mm), and 37.5–49.5% (Cu 0.25 mm), corresponding to 0.04 mmPb. Scattered radiation shielding efficiency ranged from 36–58% (1 layer) and 61– 80% (1.5 layers). Phantom tests confirmed an average 29% dose reduction without significant ABC-driven parameter increases, and SNR/CNR changes were not statistically significant (p > 0.05).

Linear generators are used in free-piston Stirling engines (FPSE) because of their reciprocating mechanism. In the FPSE, the generator is driven using the motor mode to drive the engine. Once the engine begins to operate, the generator mode is used. For this reason, a single-phase linear permanent magnet generator (SPLPMG) suitable for the reciprocating motion of a mechanism-driven type and a simple initial driving operation is applied to a Stirling engine. However, compared with rotating machines, it is not as easy to evaluate the detent force and output power of a linear permanent magnet generator. It is particularly important to evaluate the former because the generator includes a permanent magnet. To analyze the characteristics of the linear generator, the detent force and static thrust were analyzed using finite element analyses. In addition, the composition and evaluation methods of the test rig for evaluating the detent force and static thrust are proposed. Finally, the evaluated static thrust was converted into an output and compared with the analytical results. Findings confirmed that the finite-element and experimental results of the proposed method were similar.