• Journal of Biomedical Engineering Research
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• v.32 no.3
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• pp.251-256
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• 2011

Virtual colonoscopy is favored over conventional colonoscopy because its non-invasive procedure can avoid complications that may happen in a conventional approach and because it can cleanse colon electronically instead of uncomfortable conventional colon cleansing. Electronic Colon Cleansing(ECC) has to deal with not only removing tagged fecal material but also recovering Partial Volume Effect(PVE) due to tagging material. This paper proposes an ECC method restoring inherent natural PVE while previous approaches focused only on reducing PVE due to tagged fecal material. The proposed method reduces PVE using 3-dimensional adaptive density correction and then replaces tagged fecal material into air. Next, it generates natural PVE for the replaced air adjacent to soft tissue and finally makes smooth transition of gray values for soft tissue adjacent to the replaced air. The proposed method applied to eleven patient data, and showed promising results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.429-439
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• 2020

This study examined the effect size of virtual reality programs on the upper extremity function of stroke patients through a meta-analysis. Databases, such as the Research Information Sharing Service, the Korean Studies Information Service System, the National Library of Korea, the Korean Citation Index, and the National Digital Science Library, were used. Previous articles were surveyed for virtual reality programs between January 2010 and June 2019. A meta-analysis was performed by selecting the final 14 studies based on the PICO standard. The RoB and RoBANS tools were used as quality assessment tools for randomized and non-randomized control trials, respectively. The CMA 3.0 program was used to calculate the effect size of each study. Sub-group analysis, meta-regression analysis, and publication bias were performed. The total effect size of the virtual reality programs on the upper extremity function was Hedges's g=0.390 (95% CI: 0.192~0.587) (p<.05). The virtual reality program positively affects the upper extremity function of stroke patients. Therefore, the development of various virtual reality programs and industry-academia cooperation technology for stroke patients is required in accordance with the fourth industry. Randomized control trials and detailed upper extremity function studies for virtual reality programs will be needed in follow-up studies.

• Journal of the Korean Society of Radiology
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• v.17 no.4
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• pp.573-579
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• 2023

This study compares dose difference between the presence or absence of grid in Chest PA radiography using auto exposure control and compares image quality among presence, absence or virtual grid, and proposes a new clinically useful grid combination for chest radiography. The human body phantom was placed Chest PA position and the dosimeter was placed at T6. The same irradiation conditions and field size were applied. 30 images were obtained in the state in which grid was applied and in the state in which grid was not applied, and an additional 30 images in which the virtual grid was applied to the image without the grid were obtained. Radiation dose was presented to entrance surface dose. The image quality was analyzed by comparing the signal-to-noise and contrast-to-noise ratio. ESD decreased by 48% when the grid was not used, compared to when the grid was used. SNR and CNR increased by 32% and 30% compared to grid use when grid was not used, respectively. In the case of using the virtual grid, it increased by 18% and 16% respectively, compared to the case of using the grid. As a result of this study, it is believed that when using a virtual grid instead of a grid, the quality of the image can be maintained while reducing the patient dose.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.1
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• pp.57-64
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• 2022

Additional dentition images are needed because the dentitions are distorted in cone-beam computed tomography (CBCT) due to streak artifacts and non-uniformity of the x-ray beam. The purpose of this study is to evaluate the feasibility of improving the dentition image of CBCT scan with intraoral scanner instead of plaster models. Maxilla images from plaster models, two intraoral scanners, and CBCT of 20 patients aged 12 to 18 were used in this study. With one of the intraoral scanners, the full arch was scanned by three segments and combined into a complete full arch. Virtual skull-dentition hybrid images from intraoral scanners were superimposed with the images from plaster models to evaluate the coordinate value difference and distance at reference points. The results showed that the coordinate value difference and distance were smallest with segmented intraoral scan, which showed only 2 ㎛ distance. Intraoral scan may provide good dentition images for virtual skull-dentition images.

• Journal of Dental Anesthesia and Pain Medicine
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• v.24 no.3
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• pp.195-204
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• 2024

Background: Distraction is a technique used to divert a patient's attention from unpleasant procedures. This study aimed to evaluate the effectiveness of kaleidoscopy, virtual reality, and video games in reducing anxiety and pain during invasive dental procedures in children. Methods: Sixty-six children aged 6 to 9 years were randomly assigned to three groups during local anesthesia administration: Group 1 (kaleidoscope), Group 2 (virtual reality), and Group 3 (mobile video games). The anxiety of the children was evaluated using physiological measures (heart rate) at three different time points: before, during, and after the procedure. The Raghavendra, Madhuri, and Sujata pictorial scale was used as a subjective measure before and after the procedure. Subjective measures of pain were assessed using the Wong-Baker Faces Pain Scale. The data were statistically analyzed using the Kruskal-Wallis and Wilcoxon signed-rank tests. Results: In the intergroup comparison, there were no statistically significant differences in the physiological measures of anxiety scores between the three groups before, during, and after distraction. Raghavendra, Madhuri, and Sujata pictorial scale scores were assessed before and after distraction, but no statistically significant differences were observed. Among the three groups, the children in Group 2 showed a significant reduction in pain scores. Conclusion: Compared with kaleidoscopes and video games, virtual reality is a promising distraction technique for reducing dental fear, anxiety, and pain during local anesthesia administration in children.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.3
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• pp.619-624
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• 2024

Scaling is one of the most basic dental gum treatments and involves removing tartar that has hardened on teeth. However, inexperienced and unprofessional removal of tartar may damage the gums, resulting in excessive bleeding or damage to the teeth. For this reason, scaling must be done delicately according to the gum structure of various people, and sufficient practice must be provided. Related departments at the university are conducting scaling exercises. However, from the perspective of students who have not had sufficient practice, selecting subjects and conducting practice is not easy, and practice subjects may also avoid participating in practice due to discomfort and anxiety. Accordingly, in this study, we designed and implemented a virtual reality practice system using VR to create a virtual patient rather than an actual subject and implement various gum shapes step by step to enable repetitive practice and various scaling experiences.

• Journal of Korea Multimedia Society
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• v.14 no.12
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• pp.1517-1527
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• 2011

This paper presents a motion capture based rehabilitation training system for a lower-limb paretic patient. The system evaluates the rehabilitation status of the patient by using the bend posture of the knees and the weight balance of the body. The posture of both legs is captured with a single camera using the planar mirror. The weight distribution is obtained by the Wii Balance Board. Self-occlusion problem in the tracking of the legs is resolved by using k-nearest neighbor based clustering with body symmetry and local-linearity of the posture data. To do this, we present data normalization and its symmetric property in the normalized vector space.

• Journal of the Korean Society of Radiology
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• v.10 no.1
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• pp.39-44
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• 2016

This study is fulfilled to evaluate the exposure dose nearby a patient during the brachytherapy of the prostate cancer treatment and to minimize the radiation exposure by evaluating the exposure dose of the person near the relevant implanted patient, technicians and gardians. The experiment method is used on the study is MCNPX that is stood on the basis monte-carlo method and implant the source to MIRD-type phantom in $^{192}Ir$, $^{125}I$, and $^{103}Pd$ in virtual space. For dose evaluations according to distance, the radiation dose on the patient near the corresponding implanted patient is evaluated by each distance of 30, 50, 100, 200 cm to anterior from the implanted patient. As a result, $^{192}Ir$ showed a higher dose than $^{125}I$ and $^{103}Pd$ in every distance.

• The Journal of Information Technology
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• v.5 no.4
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• pp.45-55
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• 2002

Virtual Reality(VR) is a new technology which makes humans communicate with computer. It allows the user to see, hear, feel and interact in a three-dimensional virtual world created graphically. In this paper, we introduced VR into psychotherapy area and developed VR system for the exposure therapy of acrophobia. Acrophobia is an abnormal fear of heights. Medications or cognitive-behavior methods have been mainly used as a treatment. Lately the virtual reality technology has been applied to that kind of anxiety disorders. A virtual environment provides patient with stimuli which arouses phobia, and exposing to that environment makes him having ability to over come the fear. In this study, the elevator stimulator that composed with a position sensor, head mount display, and audio system, is suggested. To illustrate the physiological difference between a person who has a feel of phobia and without phobia, heart rate was measured during experiment. And also measured a person's HR after the virtual reality training. In this study, we demonstrated the subjective effectiveness of virtual reality psychotherapy through the clinical experiment.

• Korean Journal of Computational Design and Engineering
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• v.16 no.5
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• pp.315-322
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• 2011

The goal of total knee replacement (TKR) surgery is to replace patient's knee joint with artificial implants in order to restore normal knee joint functions. Since mismatched knee implants often cause a critical balancing problem and short durability, designing a well-fitted implant to a patient's knee joint is essential to improve surgical outcomes. We developed a software system that three-dimensionally (3D) simulates TKR surgery based upon 3D knee models reconstructed from computed tomography (CT) imaging. The main task of the system was to extract precise 3D anatomical parameters of a patient's knee that were directly used to determine a custom fit implant and to virtually perform TKR surgery. The virtual surgery was simulated by amputating a 3D knee model and positioning the determined implant components on the amputated knee. The test result shows that it is applicable to derive surgical parameters, determine individualized implant components, rehearse the whole surgical procedure, and train medical staff or students for actual TKR surgery. The feasibility and verification of the proposed system is described with examples.