• Journal of the Korean Society for Precision Engineering
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• v.26 no.12
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• pp.138-145
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• 2009

Custom medical treatment is being widely adapted to lots of medical applications. A technology for 3D modeling is strongly required to fabricate medical implants for individual patient. Needs on true 3D CAD data of a patient is strongly required for tissue engineering and human body simulations. Medical imaging devices show human inner section and 3D volume rendering images of human organs. CT or MRI is one of the popular imaging devices for that use. However, those image data is not sufficient to use for medical fabrication or simulation. This paper mainly deals how to generate 3D geometry data from those medical images. A new image processing technology is introduced to reconstruct 3D geometry of a human body vacancy from the medical images. Then a surface geometry data is reconstructed by using Marching cube algorithm. Resulting CAD data is a custom 3D geometry data of human vacancy. This paper introduces a novel 3D reconstruction process and shows some typical examples with implemented software.

• The Journal of the Korea Contents Association
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• v.11 no.2
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• pp.322-330
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• 2011

To compare of quality control for chest radiography between special examination (SEP) and medical institution for pneumoconiosis (MIP). For the first time, we had visited at 33 institutions (SEP; 17 institutions, MIP; 16 institutions) to evaluate the quality control of chest radiography which is used in diagnosis of patients with pneumoconiotic complications. Image quality was rated by two experienced chest radiologists, and evaluated for radiological technique (RT), reading environment (RE) and image quality (IQ) between SEP and MIP according to the guideline published by OSHRI. Generator capacity, used duration and modality of chest radiography equipment were not signigicant difference between SEP and MIP, but there were signigicant difference in tube voltage and grid ratio used for chest radiography except to tube current and exposure time. SEP was statistically significant higher in RT (71.2 vs. 54.5, p=0.015), RE (78.8 vs. 51.5, p=0.007) to MIP, but not significant difference in IQ (64.8 vs. 59.3, p=0.180). For reliable and precisional diagnosis of patients with pneumoconiotic complications, the MIP requires the evaluation and education of quality control for improving chest radiography.

• Progress in Medical Physics
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• v.21 no.1
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• pp.99-112
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• 2010

In Republic of Korea, there are many Quality Assurance protocol for general radiation treatment machine such as linac. However, Quality Assurance protocol for radiosurgery treatment system is not ready perfectly. One of the radiation treatment machine for radiosurgery, novalis system needs to suitable Quality Assurance protocol for using it right way during radiation treatment and maintaining suitable accuracy for daily, weekly, monthly and annually periods. Therefore, in this article, we develop Quality Assurance protocol for novalis system. We collected and analysed domestic and foreign novalis Quality Assurance protocol. After that, we selected essential QA items and each tolerance range for developing proper QA protocol, and we made anatomical phantom for execution of selected QA items and evaluation of overall state of QA, and then, we use this measured value as a reference. Quality Assurance items are consisted of Mechanical accuracy QA part and Radiation delivery QA part. Mechanical accuracy QA part is comprised of radiation generation machine part, assistive devices part and multi-leaf collimator part. Radiation delivery QA part is divided into radiation isocenter accuracy and dosimetric evaluation. After that, developed novalis QA tables are made by using these QA items. These novalis QA tables would be used to good standard in order to maintain apt accuracy for radiosurgery in daily, weekly, monthly and annually periods.

• Progress in Medical Physics
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• v.21 no.4
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• pp.360-366
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• 2010

To generate on-board digital tomosynthesis (DTS) for three-dimensionalimage-guided radiation therapy (IGRT) as an alternative to conventional portal imaging or on-board cone-beam computed tomography (CBCT), two clinical cases (liver and bladder) were selected to illustrate the capabilities of on-board DTS for IGRT. DTS images were generated from subsets of CBCT projection data (45, 162 projections) using half-fan mode scanning with a Feldkamp-type reconstruction algorithm. Digital tomosynthesis slices appeared similar to coincident CBCT planes and yielded substantially more anatomic information. Improved bony and soft-tissue visibility in DTS images is likely to improve target localization compared with radiographic verification techniques and might allow for daily localization of a soft-tissue target. Digital tomosynthesis might allow targeting of the treatment volume on the basis of daily localization.

• Health Policy and Management
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• v.25 no.4
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• pp.253-255
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• 2015

The concept of precision medicine-prevention and treatment strategies that take individual variability into account-is hot issue of US in the year 2015. Precision medicine is a new concept that approach patients individually by there characteristics, such as genome, life style, environmental exposure, etc. For developing the precision medicine, National Institute of Health of US has been prepared the Precision Medicine Initiative Cohort Program, at least 1 million people cohort. The US President Obama announced the Precision Medicine Initiative on 30th January 2015. He announced that he will pioneer a new model of patient-powered research that promises to accelerate biomedical discoveries and provide clinicians with new tools, knowledge, and therapies to select which treatments will work best for which patients. Most medical treatments have been designed for the 'average patient.' As a result of this 'one-size-fits-all-approach,' treatments can be very successful for some patients but not for others. This is changing with the emergence of precision medicine, an innovative approach to disease prevention and treatment that takes into account individual differences in people's genes, environments, and lifestyles. Precision medicine gives clinicians tools to better understand the complex mechanisms underlying a patient's health, disease, or condition, and to better predict which treatments will be most effective. The healthcare researcher should prepare the new medicine era such as bio-information technology convergence, big data study.

• The Journal of the Korean life insurance medical association
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• v.25
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• pp.103-118
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• 2006

근래에 한국의 생명보험 시장에는 주요 질병의 보장을 위한 상품들이 연일 쏟아져 나오고 있다. 그러나 이와 함께 증가될 수 있는 리스크에 대한 대비는 상대적으로 부족한 실정이다. 특히 간질환에 의한 급부발생이 타질환에 비하여 현격하게 높은 국내 실정에 맞게 언더라이팅 초점이 맞추어져야 할 필요가 있다. 간질환 유발인자로 대표적인 것은 B형 간염이지만, 과다한 알코올 섭취에 의한 간질환 역시 매해 빠른 속도로 증가하는 추세이다. 따라서 본 논문에서는 알코올에 의한 질환의 종류와 이와 관련된 보험금 청구 통계, 그리고 음주로 인한 교통사고의 폐해에 대해 살펴보고, 알코올 남용자를 사전에 판별할 방법을 찾아보고자 한다. 일반적으로 알려져 있는 알코올 관련 질환으로는 지방간, 알코올성 간염, 알코올성 간경변이 있으며, 이로 인한 급부발생율은 급격히 증가하고 있다. 음주로 인한 폐해는 단순히 간질환에 그치지 않고 있으며, 교통사고의 상당수가 음주와 관련이 되어있다. 이러한 리스크에 대해 국내의 상당수 보험사들은 혈액검사를 통하여 간기능에 대한 기준을 설정하여 언더라이팅을 하고 있다. 현재 주로 시행되고 있는 간기능 검사들에 대한 정확도에 대해서는 논란이 있을 수 있다. 따라서 보다 정밀한 검사법들에 대한 연구가 필요할 것이다. 외국의 경우, 보험을 가입하고자 하는 보험 대상자들은 직업이나 흡연, 위험 취미뿐만 아니라 알코올과 관련된 일정한 양식의 질문표에 대하여 성실하게 고지하도록 하고 있다. 국내에도 알코올과 관련된 자세한 고지항목을 첨부하여, 일정 기준에 미치지 못하는 가입자에 대하여 표준미달체로 분류하여 보다 정밀한 검진을 통해 세밀한 언더라이팅이 이루어져야 하겠다. 이와 아울러, 알코올로 인한 사회적 폐해의 심각성에 대한 인식 확대를 위한 각 보험사 및 유관기관의 노력이 전개된다면, 음주에 대한 진사 절차가 수월해질 것으로 기대된다.

• The Korean Journal of Applied Statistics
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• v.35 no.1
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• pp.77-91
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• 2022

The optimal threshold estimation is considered in order to discriminate the mixture distribution in the fields of Biostatistics and credit evaluation. There exists well-known various accuracy measures that examine the discriminant power. Recently, Matthews correlation coefficient and the F1 statistic were studied to estimate optimal thresholds. In this study, we explore whether these accuracy measures are appropriate for the optimal threshold to discriminate the mixture distribution. It is found that some accuracy measures that depend on the sample size are not appropriate when two sample sizes are much different. Moreover, an alternative method for finding the optimal threshold is proposed using the correlation coefficient that defines the ratio of the confusion matrix, and the usefulness and utility of this method are also discusses.

• Progress in Medical Physics
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• v.10 no.2
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• pp.89-94
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• 1999

We developed a sterotactic radiosurgery system which is comprised of 1) collimators with small circular aperture, 2) an angiographic target localizer, 3) a target localizer used for alignment of planned target position with isocenter of treatment machine, and 4) a treatment planning system named LinaPel. In this study, we performed a series of treatment simulations to specify and analyze geometrical errors contained our in-house radiosurgery system. As results, 1) using Geometrical Phantom(Radionics,USA), the accuracy of target localization by LinaPel was determined as Avg. =(equation omitted) the accuracy of mechanical isocenter was found out to be 0.6 $\pm$ 0.2 mm, 3) the positional difference of target localization which determined by CT and angiography was 0.8 mm, and their size difference was 1.5 mm, and 4) the positional error during whole treatment was found out to be 0.9 $\pm$ 0.3 mm. With these results, we concluded that our in-house radiosurgery system can be used clinically. However, these range of accuracies need periodical quality assurance strongly.

• Progress in Medical Physics
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• v.6 no.2
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• pp.93-101
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• 1995

In this paper, we implemented a digital medical image management and a remote monitor display system for a personal computer. The designed system can display up to a 1280${\times}$1024 image which can accomodate eight images with a 256${\times}$256${\times}$8bits. When one of these images is clicked by the mouse, the selected image can be displayed with 256${\times}$256${\times}$8bits or 1024${\times}$1024${\times}$8bits. For the selected image, we can use one of the image processing functions in this system and send it to a remote monitor for the close examinations. To search and store digital images effectively, we constructed and image database management system with the B＋TREE structure. This system can be operated in an IBM-PC 386 or higher and all the function are performed easily with a mouse to provide a user firendly environment.

• Progress in Medical Physics
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• v.15 no.1
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• pp.9-16
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• 2004

The intensity modulated radiation therapy (IMRT) is believed to be on of the best treatment techniques for the goal of radiation therapy: to irradiate fatal dose to tumor region while minimizing dose to critical organs. It is essential to have comprehensive quality assurance program to assure the precision and the accuracy of the treatment due to the characteristic of the IMRT. The quality assurance technique for the Corvus treatment planning system was developed and its effectiveness was tested with the treatment planning of H&N region. Acrylic phantom, film and ionization chamber were used for this study, the discrepancy between the treatment planning and the film measurements showed 0.03 cm and 0.28 cm for the 90% of isodose line in each directions. Dose measurements showed 1% and 1.2% differences for ionization chamber and TLD, respectively. This concluded that the system can be used for clinic.