• Proceedings of the Korean Information Science Society Conference
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• 2002.10d
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• pp.553-555
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• 2002

컴퓨터지원진단(Computer Aided Diagnosis; CAD) 시스템은 방사선 의사들이 흉부 X-ray 영상에서 결절을 탐지하는데 있어 실제적으로 발생할 수 있는 오진율을 줄이고, 폐 결절이 존재하는 폐야에서 결절의 존재 유무를 판단하여 검출을 표시함으로써 진단율을 개선시킬 수 있도록 하였다. 본 논문은 흉부 X-ray 영상에서의 폐 결절을 추출하는데 유전자 알고리즘(Genetic Algorithm)을 이용한 템플릿 매칭(Template Matching) 방법을 제안한다. 제안한 방법은 흉부 X-ray 영상에 존재하는 결절과 레퍼런스 이미지를 매칭시켜 적합도를 계산한 후, 그 값을 통하여 수치가 낮은 개체를 선택하여 높은 개체와 교차시킨다. 그리고 레퍼런스 이미지는 결절이 존재하는 환자 X-ray 영상에서 샘플 노듈을 추출한 후 가우시안 분포를 갖는 512개의 레퍼런스 이미지를 생성하였다. 본 논문에서 사용된 영상은 결절 50개, 비결절 30개와 흉부 X-ray 영상에서 육안으로 판별이 가능한 결절 영상을 20개를 포함하여 총 100개 영상을 사용하였다. 실험 결과 83%의 결절을 자동 추출 하였으며, 가장 적절한 레퍼런스 이미지를 발견하고 이를 흉부영상에 매칭시켜 정확한 결절의 위치를 확인하였다.

• Journal of The Korean Radiological Technologist Association
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• v.29 no.1
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• pp.25-30
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• 2003

Purpose : The purpose of this study is to present computer-capturing method of dynamic images on fluoroscopic studies, as a substitution for video-recording method, and to help the quantitative analysis of the dynamic studies. Materials and Methods: Compu

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.15-17
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• 1996

In this paper, the therapy radiation dose measurement system has been implemented by using a microcomputer after radiation was irradiated on diodes from the MM22 microtron accelerator. We have displayed 7-channel diode output values on the LCD after processing those in the 80196 MCU(Micro Computer Unit). Signal processing has been performed in the pulse mode because we can process the signal fast and use it to perform portal image by increasing a number of diode channels in the future. In order to verify the microcomputer based radiation measurement system of diodes, diode output values were compared with that of semiconductor.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.5
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• pp.19-23
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• 2004

최근 산업의 고도화와 함께 초고온, 방사선노출 등과 같은 극한환경에서 사용되는 구조물과 MEMS 와 같은 미소 구조물(Hicrostructure)이 많아지고 있으며, 이들의 변형해석을 위한 기존의 접촉식 기법들은 그 한계를 극복해야 할 필요가 있다 해결방안으로 레이저를 이용한 비접촉 측정방식이 많은 발전을 해오고 있으며, 특히, 스페클간섭법(Speckle inteferometry)기반의 변형해석 기술이 가장 뛰어난 기술로 인정받고 있다. 스페클간섭법은 컴퓨터 화상처리기술에 힘입어 전자처리 스페클간섭법(Electronic Speckle Pattern Interferometry : ESPI)으로 발전을 하고 있으며, 자동차와 같은 대형구조물의 변형해석에서 MEMS 구조물과 같은 미소구조물 변형해석까지 그 적용범위가 매우 넓다. 본 논문에서는 ESPI 를 이용한 변형해석분야의 국내외 기술현황 및 적응사례, 발전방향를 소개하였다.(중략)

• The Journal of Korean Society for Radiation Therapy
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• v.22 no.2
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• pp.135-144
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• 2010

Purpose: The purpose of this study is that through production of phantom for respiration gated radiotherapy, assessing appropriacy of exposure dose for the therapy using RPM (Real-time Position Management). Materials and Methods: We located measurement object on the phantom for respiration gated radiotherapy made of 2 linear actuator, acrylic panel, stanchion, iron plate ets. to drive (up, down, front, back). Using 4D CT scan, we analyzed patient's respiration and reproduced the movement by computer. On the phantom, we located a 2D-Array (PTW) and an White water phantom (4.5 cm) and used DMLC (interval 2 cm) in the field size $10{\times}10\;cm$, then exposed 21EX X-ray 100 MU, in the case of phantom was (1) static (2) moving (3) gated using RPM respectively gantry $0^{\circ}$ and $90^{\circ}$ We measured with a 0.125 CC ionization chamber (PTW) on the phantom (7.5 cm) in the same condition. Results: Ionization chamber: There were within 0.3% of error with gating respiration and approximately 2% of error without gating in the same condition. 2D-Array: Gantry $90^{\circ}$, field size $10{\times}10\;cm$, using DMLC. There were within 3% of error with gating respiration and approximately 16% of error without gating. Conclusion: The phantom for respiration gated radiotherapy makes plans considering patient's movement, quantitative analysis of exposure dose and proper assessment therapy for IMRT patients using RPM possible.

• Progress in Medical Physics
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• v.17 no.1
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• pp.24-31
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• 2006

Automated analysis software was developed to measure the magnitude of the intrafractional and interfractional errors during breast radiation treatments. Error analysis results are important for determining suitable planning target volumes (PTV) prior to Implementing breast-conserving 3-D conformal radiation treatment (CRT). The electrical portal imaging device (EPID) used for this study was a Portal Vision LC250 liquid-filled ionization detector (fast frame-averaging mode, 1.4 frames per second, 256X256 pixels). Twelve patients were imaged for a minimum of 7 treatment days. During each treatment day, an average of 8 to 9 images per field were acquired (dose rate of 400 MU/minute). We developed automated image analysis software to quantitatively analyze 2,931 images (encompassing 720 measurements). Standard deviations ($\sigma$) of intrafractional (breathing motion) and intefractional (setup uncertainty) errors were calculated. The PTV margin to include the clinical target volume (CTV) with 95% confidence level was calculated as $2\;(1.96\;{\sigma})$. To compensate for intra-fractional error (mainly due to breathing motion) the required PTV margin ranged from 2 mm to 4 mm. However, PTV margins compensating for intefractional error ranged from 7 mm to 31 mm. The total average error observed for 12 patients was 17 mm. The intefractional setup error ranged from 2 to 15 times larger than intrafractional errors associated with breathing motion. Prior to 3-D conformal radiation treatment or IMRT breast treatment, the magnitude of setup errors must be measured and properly incorporated into the PTV. To reduce large PTVs for breast IMRT or 3-D CRT, an image-guided system would be extremely valuable, if not required. EPID systems should incorporate automated analysis software as described in this report to process and take advantage of the large numbers of EPID images available for error analysis which will help Individual clinics arrive at an appropriate PTV for their practice. Such systems can also provide valuable patient monitoring information with minimal effort.

• Radiation Oncology Journal
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• v.20 no.3
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• pp.264-273
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• 2002

Purpose : Three-dimensional radiation dosimetry using magnetic resonance imaging of polymer gel was recently introduced. This dosimetry system is based on radiation induced chain polymerization of acrylic monomers in a muscle equivalent gel and provide accurate 3 dimensional dose distribution. We planned this study to evaluate the clinical value of this 3-dimensional dosimetry. Materials and Methods: The polymer gel poured into a cylindrical glass flask and a spherical glass flask. The cylindrical test tubes were for dose response evaluation and the spherical flasks, which is comparable to the human head, were for isodose curves. T2 maps from MR images were calculated using software, IDL. Dose distributions have been displayed for dosimetry. The same spherical flask of gel and the same irradiation technique was used for film and TLD dosimetry and compared with each other. Results : The R2 of the gel respond linearly with radiation doses in the range of 2 to 15 Gy. The repeated dosimetry of spherical gel showed the same isodose curves. These isodose curves were identical to dose distributions from treatment planning system especially high dose range. In addition, the gel dosimetry system showed comparable or superior results with the film and TLD dosimetry. Conclusion : The 3-dimensional dosimetry for conformal radiation therapy using MRI of polymer gal showed stable and accurate results. Although more studies are needed for convenient clinical application, it appears to be a useful tool for conformal radiation therapy.

• Journal of Veterinary Clinics
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• v.26 no.4
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• pp.371-375
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• 2009

A three-year-old Beagle dog was presented with the neck mass. Mass was located at ventral part of the mandible. The dog showed excessive drooling. Sialocele with calculi was evaluated based on physical exam, radiographs, ultrasonography, and computed tomography. Salivary gland resection was performed. Histopathological examination confirmed sialoadenitis concurred with sialocele.

• Journal of the Korean Society of Radiology
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• v.3 no.2
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• pp.5-10
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• 2009

Myocardial imaging in SPECT (Single Photon Emission Computed tomography) scan of the gamma-ray emitting radiopharmaceuticals to patients after intravenous radiopharmaceuticals evenly spread in the heart region of interest by recording changes in the disease caused by a computer using the PSA test is to diagnose. Containing information on the functional myocardial perfusion imaging is a useful way to examine non-invasive heart disease, but the argument by noise and low resolution of the physical landscape that is difficult to give. For this paper, the level of myocardial imaging by using the three algorithms to split the video into 3-D implementation of the partitioned area to help you read the proposed plan. To solve the difficulty of reading level, interest in using the sheet set, partitioned area of the left ventricle was ranked the partitioned area was modeled as a 3-D images.

• Journal of the Korean Society of Radiology
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• v.7 no.5
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• pp.359-364
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• 2013

Femur is the largest bone in the human body which supports the weight of body. A long pipeline shape of femur has little cancellous bone, so that regeneration is difficult when fracture happens. The fracture caused by an accident most frequently occurs at diaphysis. IM Nailing is the surgical method that implants an IM Nail into a medullary cavity for the fixation of fracture parts. However, a secondary fracture may happen if an IM Nail does not penetrate at the center of femur. In this study, a patient-specific femur was manufactured by a 3D printer using the computed tomography images scanned before surgery, which was used for the simulation of IM Nailing. It is expected that this result may prevent the secondary damage, reduce surgical operation time, and increase the precision.