https://scholar.dgist.ac.kr/handle/20.500.11750/12141 2026-04-05T06:27:33Z https://scholar.dgist.ac.kr/handle/20.500.11750/59977 Title: Golay-Net: Deep learning-based Golay coded excitation for ultrasound imaging Author(s): Hwang, Suntae; Kim, Jinwoo; Lee, Eunji; Chang, Jin Ho Abstract: Ultrasound imaging modality, which operates by transmitting and receiving short ultrasound pulses, offers a promising approach for real-time, high-resolution diagnostic imaging at relatively low cost. However, the conventional short-pulse approach is inherently limited by signal attenuation with increased imaging depth, leading to reduced penetration and a lower signal-to-noise ratio (SNR), which ultimately degrades diagnostic performance. Golay-coded excitation has been introduced to mitigate these issues by transmitting longer, coded pulses that use a pair of complementary sequences (Codes A and B) to enhance SNR and imaging depth. However, this technique requires two sequential transmissions to acquire two echoes related to the complementary codes, inevitably reducing the frame rate by half. In this work, we propose a novel deep learning framework that overcomes this limitation by generating the echo signal corresponding to Code B from the echo signal obtained after transmitting code A. For this, we developed Golay-Net, based on a 1-D U-Net architecture, which changes the phase of the range sidelobes of the Code A-related echo signals, thereby effectively synthesizing the echo signals that would have been obtained using Code B. In vitro and in vivo experiments demonstrate that the proposed Golay-Net can synthesize code B-related echo signals with high fidelity, enabling the reconstruction of ultrasound images with enhanced SNR and imaging depth, without compromising frame rate. 2026-02-28T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59884 Title: Intravascular ultrasound imaging with directional synthetic aperture focusing and coherence factor weighting Author(s): Cho, Hyunwoo; Lee, Jaebin; Park, Daehyun; Chang, Jin Ho; Jang, Jihun; Yoo, Yangmo Abstract: Purpose: Intravascular ultrasound (IVUS) is widely used to visualize vascular structures and assess atherosclerotic plaques, particularly for evaluating the risk of rupture. Although increasing the center frequency of the transducer can enhance spatial resolution, it also increases attenuation, which substantially degrades image quality at greater depths. To mitigate this trade-off, synthetic aperture focusing (SAF) techniques have been studied; however, when applied to single-element rotational IVUS systems, they have yielded only minimal improvements and introduced undesirable artifacts. Methods: In this work, a directional SAF (dSAF) method is proposed to address these limitations. The convex nature of the point spread function in rotational IVUS scanning is analyzed to track the true direction of echo signals, enabling the selective exclusion of off-axis signals. By focusing only on valid signals during synthesis, resolution degradation and artifact formation are prevented, and the fidelity of the reconstructed image is preserved. Results: Validation through simulations and phantom experiments indicates that the dSAF method achieves an average 37.3% improvement in lateral resolution and an 8.6% increase in contrast-to-noise ratio, without degrading penetration depth. Conclusion: These findings suggest that directional echo screening effectively mitigates the limitations encountered with conventional SAF in IVUS imaging, offering a robust pathway to improved image quality. Additionally, the proposed approach can be integrated into existing IVUS workflows, potentially expediting clinical adoption and advancing intravascular diagnostic capabilities. 2025-10-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59877 Title: Streamlining the cell flow: Feasibility of acoustically driven cell alignment for in vivo flow cytometry Author(s): Kim, Jinwoo; Kwon, Jae Gwang; Bark, Hyeon Sang; Chang, Jin Ho; Kim, Haemin Abstract: In vivo flow cytometry (IVFC) utilizes blood vessels as natural conduits for real-time and noninvasive monitoring of circulating cells. However, conventional IVFC systems are primarily limited to superficial vessels, restricting analytical throughput and diagnostic sensitivity. Here, we propose a novel acoustic-based cell alignment strategy that allows IVFC to be applied in a broader range of vascular locations. We developed a dual ultrasound transducer (DUST) system in which two transducers are positioned face-to-face at the same angle. This configuration generates an interference-based acoustic field containing periodically arranged pressure nodes and antinodes within the vessel. The resulting field aligns flowing cells into multiple parallel streamlines, concentrating their movement within a confined region and enhancing the consistency and efficiency of signal detection. Blood vessel mimicking phantom experiments demonstrated that a dual ultrasound (DUS) enables stable multiple parallel streamlines of microbeads in a vessel while maintaining uniform flow velocity. Furthermore, fluorescent beads modeling rare cells exhibited approximately a 9-fold increase in signal-to-noise ratio (SNR) under DUS application compared to the non-aligned condition. Signal intensity fluctuations at the detection point were also significantly reduced, enabling more stable and reliable signal analysis. This approach demonstrates strong potential for highly sensitive, single-cell-level diagnostics in vivo. It also enables seamless integration with photoacoustic or fluorescence-based detection systems for future multimodal single-cell analysis. 2025-11-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59168 Title: Handpiece for light treatment and treatment method using same Author(s): 장진호; 김진우; 김혜민 Abstract: The invention provides a handpiece for light therapy. In one embodiment, the handpiece for light therapy may include: a main body portion provided in a cylindrical shape to be gripped by a user; an ultrasonic wave generation unit which is provided at one end of the main body unit and which irradiates ultrasonic waves to the treatment site so as to increase the temperature of the treatment site to a set temperature; a laser irradiation unit which is provided inside the main body unit and irradiates laser light to the treatment site; and a housing coupled to the tip of the ultrasonic wave generating unit and housing therein a medium for transmitting ultrasonic waves to the treatment site, in which the ultrasonic wave generating unit may comprise: a frame coupled to the upper part of the housing and having a through-hole through which the laser beam passes; and an ultrasonic element coupled to the frame.