• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.597-603
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• 2019

We obtained a Dicom file using a CT (Computed Tomography), a diagnostic test device used in clinical practice. Dicom files and 3D programs, and finger printers with 3D printers. Because the finger brace is intended for the human body, the accuracy of the shape is very important. 3D Print has the advantage of high precision, variety of materials, and short output time. In clinic, aluminum protector or medical device manufacturer's finger protector is limited. By creating a finger brace with a 3D printer, we expect to be able to apply a precise form of a custom finger brace to the patient that can be used to treat a patient's finger trauma, illness, or deformity.

• Journal of Biomedical Engineering Research
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• v.42 no.5
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• pp.232-240
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• 2021

Heterogeneity in cancer is the major obstacle for precision medicine and has become a critical issue in the field of a cancer diagnosis. Many attempts were made to disentangle the complexity by molecular classification. However, multi-dimensional information from dynamic responses of cancer poses fundamental limitations on biomolecular marker-based conventional approaches. Cell morphology, which reflects the physiological state of the cell, can be used to track the temporal behavior of cancer cells conveniently. Here, we first present a hybrid learning-based platform that extracts cell morphology in a time-dependent manner using a deep convolutional neural network to incorporate multivariate data. Feature selection from more than 200 morphological features is conducted, which filters out less significant variables to enhance interpretation. Our platform then performs unsupervised clustering to unveil dynamic behavior patterns hidden from a high-dimensional dataset. As a result, we visualize morphology state-space by two-dimensional embedding as well as representative morphology clusters and trajectories. This cell morphology profiling strategy by hybrid learning enables simplification of the heterogeneous population of cancer.

• Journal of Biomedical Engineering Research
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• v.43 no.2
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• pp.102-108
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• 2022

Purpose: To propose a deep learning-based clinical decision support technique for laryngeal disease on epiglottis, tongue and vocal cords. Materials and Methods: A total of 873 laryngeal endoscopic images were acquired from the PACS database of Pusan N ational University Yangsan Hospital. and VGG16 model was applied with transfer learning and fine-tuning. Results: The values of precision, recall, accuracy and F1-score for test dataset were 0.94, 0.97, 0.95 and 0.95 for epiglottis images, 0.91, 1.00, 0.95 and 0.95 for tongue images, and 0.90, 0.64, 0.73 and 0.75 for vocal cord images, respectively. Conclusion: Experimental results demonstrated that the proposed model have a potential as a tool for decision-supporting of otolaryngologist during manual inspection of laryngeal endoscopic images.

• Journal of Biomedical Engineering Research
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• v.40 no.5
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• pp.189-196
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• 2019

We investigated differences in ventricular and hippocampal volumes between CSF tap test (CSFTT) responders and non-responders in idiopathic normal-pressure hydrocephalus (INPH) patients and compared these parameters in INPH patients with that of age- and gender-matched healthy controls. We also evaluated relationships between ventricular and hippocampal volumes and clinical profiles in INPH patients. We enrolled 48 patients with INPH and 29 healthy controls. Ventricular and hippocampal volumes were measured on MRI, including 3-dimensional volumetric images. INPH patients, when compared to healthy controls, had significantly larger ventricular and smaller hippocampal volumes. No difference in ventricular and hippocampal volumes was found between CSFTT responders and non-responders in INPH patients. And hippocampal volumes showed significant negative correlations with Clinical Dementia Rating Scale scores, INPH grading scale cognitive scores, Timed Up and Go Test scores, and Unified Parkinson's Disease Rating Scale motor scores in INPH patients. Volumetric assessment of ventricular and hippocampal regions may have no predictive value in differentiating between CSFTT responders and non-responders in INPH patients. Our findings may help us understand the potential pathophysiology of unique symptoms associated with INPH.

• Journal of Biomedical Engineering Research
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• v.42 no.1
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• pp.1-6
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• 2021

Recently, various types of pedicle screws have been developed considering the anatomical structure of the spine. The purpose of this study was to evaluate the pullout stiffness and strength of two types of commercial pedicle screws. The design of two type screws were single pitched thread (ST) pedicle screw and dual pitched thread (DT) pedicle screw, respectively. The tests were conducted in accordance with the ASTM standards using polyurethane (PU) test blocks which has anatomical structure of the spine. There was no significant difference in pullout stiffness between two types of screw. However, DT exhibited higher pullout strength than ST (p<0.05). Pedicle screw with dual pitched thread showed higher pullout strength without decrease in pullout stiffness compared to the standard pedicle screw. In conclusion, dual pitched thread design of the pedicle screw is considered to be more suitable than the single pitched thread for the anatomical structure of the spine.

• Journal of Biomedical Engineering Research
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• v.43 no.4
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• pp.219-229
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• 2022

In this study, we propose a miniaturized micro-ceramic heater device. After screen-printing a silver paste between pre-sintered two aluminum oxide plates to integrate a heating circuit, the device was fabricated through a low-temperature sintering process. In order to configure the optimal heating circuit integration condition, the output current evaluation and heating test were performed according to the number of screen prints of the silver paste at various voltages. A silver paste-based heating circuit printed with a line width of 200 ㎛ and a thickness of 60 ㎛ was successfully integrated on a pre-sintered alumina substrate through a low-temperature sintering process. In the case of the 5 times printed device, the thermal response showed a response rate of 18.19 ℃/sec. To demonstrate feasibility of the proposed device in the medical field, such as bio-tissue suturing and hemostasis, a voltage was applied to pig tissue in the device to test tissue change due to heat generated from the device. These results show the possibility that the proposed small ceramic heater could be used in the medical field based on its excellent temperature response.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.151-157
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• 2019

Recently, monitoring respiration of people has been of interest using non-invasive method. Among the vital signals usually used for indicating health status, non-invasive and portable device based monitoring respiratory status is practically useful and enable one to promptly deal with abnormal physical status. This paper proposes the approach to real-time detection of apnea signal based on Short-Time-Fourier-Transform(STFT). Contrary to the analysis of a signal in frequency domain using Fast-Fourier Transform, this paper employs Short-time-Fourier-Transform so that frequency response can be analyzed in short time interval. The respiratory signal is acquired using UWB radar sensor that enables one to obtain respiration signal in contactless way. Detection of respiratory status is carried out by analyzing frequency response, and classification of respiratory status can be provided. In particular, STFT is employed to analyze respiratory signal in real-time, leading to effective analysis of the respiratory status in practice. In the case of existence of noise in the signal, appropriate filtering process is employed as well. The proposed method is straightforward and is workable in practice to analyze the respiratory status of people. To evaluate the proposed method, experimental results are provided.

• Journal of Biomedical Engineering Research
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• v.44 no.6
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• pp.404-413
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• 2023

In this research, we studied the development of a SUS304 microneedle array based on microfabrication technology and the applicability of Parylene-C thin film, a medical polymer material. First of all, four materials commonly used in the field of medical engineering (SUS304, Ti, PMMA, and PEEK) were selected and a 5 ㎛ Parylene-C thin film was deposited. The applicability of Parylene-C coating to each material was confirmed through SEM analysis, contact angle measurement, surface roughness(Ra) measurement, and adhesion test according to ASTM standards for each specimen. Parylene-C thin film was deposited based on chemical vapor deposition (CVD), and a 5 ㎛ Parylene-C deposition process was established through trial and error. Through characteristic experiments to confirm the applicability of Parylene-C, SUS304 material, which is the easiest to apply Parylene-C coating without pretreatment was selected to develop a microneedle array based on CNC micromachining technology. The CNC micromachining process was divided into a total of 5 steps, and a microneedle array consisting of 19 needles with an inner diameter of 200 ㎛, an outer diameter of 400 ㎛, and a height of 1.4 mm was designed and manufactured. Finally, a 5 ㎛ Parylene-C coated microneedle array was developed, which presented future research directions in the field of microneedle-based drug delivery systems.

• Journal of Biomedical Engineering Research
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• v.43 no.2
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• pp.124-130
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• 2022

In this paper, we proposed a portable electronic cardiogram and stethoscope (ECGS) that can simultaneously perform the electrocardiogram (ECG) and auscultation tests to increase the reliability of diagnosis of heart disease. To measure the ECG and heart sound (HS) at the same time, three ECG electrodes and a microphone sensor were combined into a triangular shape with a width of 90 mm and a height of 97 mm that can be held in one hand. In order to prevent skin problems when they contact the patient's skin, a capacitive coupled electrode was selected as the ECG electrode and a silicone material was used in a chest piece with the microphone sensor. For the signals measured from the electrodes and the chest piece, filters were respectively configured to pass only the signals of 0.01-100 Hz and 20-250 Hz, which are frequency bands for ECG and HS. The filtered ECG and HS analog signals were converted into digital signals and transmitted to a PC using wireless communication for monitoring them. The HS could be auscultated simultaneously using an earphone. The monitored ECG had an SNR of about 34 dB and a P-QRS-T waveform is clearly visible. In addition, the HS had an SNR of about 28 dB and both S₁ and S₂ are clearly visible. It is expected that it can aid doctors' inexperience in analyzing the ECG and HS.

• Journal of Biomedical Engineering Research
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• v.44 no.6
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• pp.465-475
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• 2023

In this study, we demonstrated a silica nanofibrous membrane based on the electrospinning process and evaluated its DNA isolation and purification performance in PCR pretreatment. Generally, silica membranes made of non-woven fabric are used for PCR pretreatment, but this study aimed to improve the efficiency of the pretreatment process by developing a nanofiber-type silica membrane with high specific surface area and porosity. In order to manufacture a nanofiber-shaped silica film while maintaining the original physical properties of silica, nanofiber membranes produced by adding various concentrations of PEO (5 wt%, 8 wt%, and 10 wt%) to silica prepared by the sol-gel method were compared. In terms of nanofiber membrane production, the higher the PEO concentration, the more effective it was in producing nanofiber membranes. The produced silica nanofiber membrane was inserted to a pretreatment device used in commercial PCR equipment, and the pretreatment performance was compared and verified using Salmonella bacteria. When Salmonella was used, samples containing 5 wt% PEO showed superior PCR efficiency compared to samples containing 8 wt% and 10 wt% PEO. These results show that adding 5 wt% of PEO can effectively improve DNA purification and separation by producing a nanofiber-shaped silica film while maintaining the physical properties of silica. We expect that this study will contribute to the development of effective PCR pretreatment technology essential for various molecular biology applications.