https://scholar.dgist.ac.kr/handle/20.500.11750/1199 2026-04-04T14:15:21Z 2026-04-04T14:15:21Z Lee, Junyeong Park, Joowon Park, Sukho https://scholar.dgist.ac.kr/handle/20.500.11750/59393 2026-01-29T08:10:12Z 2026-01-31T15:00:00Z

Title: Energy-Based Kinematic Analysis on Magnetic Soft Continuum Robot With Asymmetric Magnetization Author(s): Lee, Junyeong; Park, Joowon; Park, Sukho Abstract: Magnetically actuated soft continuum robots (MSCRs), which offer remote and wireless control via external magnetic fields along with high flexibility, have recently emerged as a promising technology for minimally invasive surgery (MIS). However, the magnetic actuation forces of MSCRs are generally limited, resulting in inherent workspace constraints. To overcome these limitations, various design strategies have been explored, including the development of an asymmetric magnetized soft continuum robot (AMSCR). Although AMSCRs have demonstrated a significantly larger workspace than conventional MSCRs, a quantitative relationship between the magnetization patterns of embedded magnetic particles and the resulting workspace has not yet been fully clarified. In this study, an energy-based kinematic analysis of AMSCR was conducted to address this issue. Specifically, the equilibrium posture of the AMSCR was determined by minimizing the total potential energy, considering different combinations of external magnetic field directions and internal magnetization patterns. Based on the resulting potential energy graph, the workspace of the AMSCR was quantitatively analyzed, and an optimal linear asymmetric magnetization pattern was identified. Furthermore, the proposed energy-based kinematic model was validated through finite element analysis (FEA) conducted using COMSOL Multiphysics, as well as through experiments performed on a fabricated AMSCR prototype. As a result, an optimal magnetization design method for linearly asymmetric AMSCRs was proposed and experimentally confirmed. The proposed approach is expected to be further applicable to the kinematic performance evaluation and design optimization of AMSCRs with various other magnetization patterns.

2026-01-31T15:00:00Z Lee, Yun-jeong Bang, Sang-won Hong, Jeong-bin Park, Sukho https://scholar.dgist.ac.kr/handle/20.500.11750/59368 2026-01-15T12:40:12Z 2025-11-30T15:00:00Z

Title: Image-Free Tumor Segmentation of Soft Tissue Using a Minimally Invasive Robotic Palpation System Author(s): Lee, Yun-jeong; Bang, Sang-won; Hong, Jeong-bin; Park, Sukho Abstract: Tumor segmentation is crucial for surgical planning and precise tumor resection for effective treatment. Traditionally, tumor localization has been performed using medical imaging techniques such as CT and MRI or through direct palpation by surgeons. However, in minimally invasive robotic surgery (MIS), these methods have limitations, including registration errors with imaging and inaccuracies caused by the subjectivity of palpation by surgeons. In this study, we introduce a robotic palpation system and an image-free process for MIS tumor segmentation using a robot. Our proposed system enables precise tumor shape differentiation through direct robotic palpation. For this, the robotic palpation system collects surface shape information through the proposed process, allowing tissue palpation at specific depths according to surface curvature. Additionally, it visualizes stiffness maps, enabling image-free tumor segmentation. In experiments using this system, evaluation of planar and curved phantom models demonstrates precise segmentation at targeted sites, with sensitivities of 0.9634 and 0.9729, and specificities of 0.9646 and 0.9878, respectively. Validation on ex-vivo porcine liver models further confirms the efficacy of our approach.

2025-11-30T15:00:00Z Kee, Hyeonwoo Lee, Hyoryong Park, Joowon Jang, Saeeun Park, Sukho https://scholar.dgist.ac.kr/handle/20.500.11750/59366 2026-01-15T12:40:11Z 2025-12-31T15:00:00Z

Title: Integrated focused ultrasound and electromagnetic actuation (FUEM) system for enhanced targeted drug delivery in brain cancer treatment Author(s): Kee, Hyeonwoo; Lee, Hyoryong; Park, Joowon; Jang, Saeeun; Park, Sukho Abstract: Glioblastoma (GBM) is the most common and aggressive malignant brain tumor, accounting for nearly half of all primary brain cancers. Despite advances in therapy, therapeutic outcomes remain poor due to the restrictive nature of the blood-brain barrier (BBB), which limits drug delivery to brain tissue. Strategies that combine BBB opening with magnetic drug targeting (MDT) are being actively investigated. However, because conventional MDT using static magnetic fields induces magnetic nanoparticles (MNPs) chain formation, this aggregation hinders MNP penetration even after BBB opening, limiting therapeutic efficacy. To overcome this challenge, we propose an integrated system combining a focused ultrasound (FUS) unit with an electromagnetic actuation (EMA) unit. The FUS unit opens the BBB with microbubbles (MBs), and the EMA unit generates dynamic magnetic fields to break MNPs chains, enhancing MNPs penetration across the BBB. BBB opening is validated using an in vitro co-culture model of endothelial and pericyte cells. With the BBB opened, 50 nm MNPs loaded with doxorubicin (DOX) exhibit significantly enhanced therapeutic efficacy against GBM cells under dynamic magnetic fields. These results demonstrate that the proposed FUEM system significantly enhances drug delivery across the BBB, offering a promising strategy for targeted drug delivery in brain cancer therapy.

2025-12-31T15:00:00Z Yang, Seungun Nguyen, Kim Tien Kee, Hyunwoo Lee, Hyoryong Kim, Jayoung Park, Sukho https://scholar.dgist.ac.kr/handle/20.500.11750/58955 2025-12-18T02:41:03Z 2025-09-30T15:00:00Z

Title: 3D Targeting of a Magnetic Particle in Blood Vessels Using a Field-Free Point in an Open-Type Electromagnetic Actuation System Author(s): Yang, Seungun; Nguyen, Kim Tien; Kee, Hyunwoo; Lee, Hyoryong; Kim, Jayoung; Park, Sukho Abstract: Recent research has increasingly focused on delivering drug-carrying magnetic particles to diseased areas using electromagnetic actuation (EMA) systems. Particularly, in these systems, creating a field-free point (FFP) and using it to steer magnetic particles in the desired direction has attracted significant attention. However, most previous studies use closed-type EMA systems, which, due to their structural characteristics, are difficult to integrate into actual surgical environments and to operate in conjunction with external imaging systems like X-ray. This study addresses these limitations by using an open-type EMA system, which is better suited for surgical integration. However, an opentype EMA system faces issues such as a significant decrease in magnetic force and an anisotropic magnetic field as the distance from the coils increases in the region of interest (ROI). To overcome these challenges, we optimized the open-type EMA system and proposed a suitable FFP generation method. Furthermore, we presented a targeting algorithm for steering a magnetic particle in blood vessels using anisotropic FFP. This proposed open-type EMA system and the control strategy using FFP were validated through multiphysics simulations and phantom experiments, proving the viability of magnetic particle targeting. © 2025 Elsevier B.V., All rights reserved.

2025-09-30T15:00:00Z