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        • SCOPUSKCI등재

          초록집 : 99mTc - RBC SPECT를 이용한 간혈관종의 진단

          문대혁,조시만,이명혜,김해련,정영화,이영상,민영일,신성해,홍기석 대한핵의학회 1991 핵의학 분자영상 Vol.25 No.1

          The value of (99m)^Tc-RBC scintigraphy and SPECT in the diagnosis of hepatic hemangioma was evaluated in 27 patients with 38 hemangiomas and 13 patients with 15 nonhemangiomas. Twenty four (63.2%) of 38 hemangiomas were detected by planar delayed RBC imaging, whereas 30 (78.9%) hemangiomas were detected by the delayed RBC SPECT. Increase in sensitivity was noted in nodules less than 2 cm in diameter. The smallest hemangioma shown by delayed RBC SPECT was 0.9 cm in diameter. All of nonhemangiomatous lesions show normal or decreased activity in delayed blood pool images. We concluded that (99m)^Tc-RBC SPECT is an accurate method for the detection of hepatic hemangioma and is more sensitive than planar imaging in depicting small lesions.

        • SCOPUSKCI등재

          부갑상선기능항진증 환자에서 Tc-99m MIBI 부갑상선 신티그라피를 이용한 병소 국소화

          문대혁,류진숙,이희경,김재승,홍승모,홍석준,신중우,공경엽 대한핵의학회 1999 핵의학 분자영상 Vol.33 No.2

          Purpose: This study was performed to evaluate the diagnostic usefulness of double-phase Tc-99m MIBI parathyroidism scintigraphy with single photon emission computed tomography (SPECT) in patients with hyperparathyroidism. We also evaluated the relationship between Tc-99m MIBI uptake and oxyphil cell contents in parathyroid glands. Materials and Methods: The subjects were 28 parathyroid glands of 10 patients who underwent Tc-99m MIBI parathyroid scintigraphy and parathyroidectomy for clinically suspected hyperparathyroidism. Early and delayed pinhole images were obtained at 15 minutes and 2 hours after injection of Tc-99m MIBI, and SPECT images were followed. The weight and oxyphil cell contents of parathyroid of tissue were obtained from pathologic specimen, and the scintigraphic findings were compared with histopathology. Results: In surgical histopathology, 6 parathyroid adenomas and 9 parathyroid hyperplasias were confirmed. The sensitivity, specificity, and positive predictive value of early and delayed images were 46.7% (7/15), 76.9% (10/13), 70% (7/10) and 667% (10/15), 92.3% (12/13), 90.9% (10/11), respectively. SPECT image detected an additional small hyperplasia. The sensitivity, specificity, and positive predictive value of combined interpretation of early and delayed images with SPECT were 733% f11/15), 100% (13/13), 100% (11/11). The sensitivity was 100% (6/6) for aenoma, whereas that was 555% (5/9) for hyperplasia. Both adenomas and hyperplasias showed significantly increased oxyphil cell contents compared with normal parathyroid glands (p<0.0001), but the oxyphil cell content and weight were not significantly different between adenomas and hyperplasias. Conclusion: Double-phase Tc-99m MIBI parathyroid scintigraphy with SPECT is useful for lesion localization m patients with hyperparathyroidism. Although both adenoma and hyperplasia have increased oxyphil cell content, the sensitivity is high in adenoma, but low in hyperplasia.

        • KCI등재후보

          멀티스크린의 발전과 초고화질 콘텐츠 응용에 대한 연구

          문대혁 대한산업경영학회 2020 산업융합연구 Vol.18 No.6

          멀티스크린 영상시스템은 하나의 스크린에 상영되는 영상을 용도에 맞게 여러 화면으로 구성하여 상영할 수 있다. 관객들은 특별한 장치 없이 폭 넓은 실감 영상을 감상할 수 있어 강한 몰입감을 얻을 수 있다. 최근 멀티스크린을 이용한 실감 영상은 Screen X나 Escape와 같은 멀티 프로젝션 기술을 바탕으로 스토리와 정보 전달이 가능한 영화로 제작되고 있다. 또한, 디스플레이의 크기는 점점 대형화 추세이고 화질도 고해상도로 향상되고 있어 HD나 UHD급 디스플레이 여러 대를 입체적으로 구성한 디지털 사이니지 형태로 발전을 가속하고 있으나 촬영된 영상을 사용하는 데는 화질열화로 인해 한계가 있다. 이번 연구는 1950년부터 현재까지 멀티스크린 영상의 발전사와 기술적 분석, 제작 방법에 대해 분석하고 멀티스크린을 이용한 영상 콘텐츠 상영 시 발생되는 화질 열화 최소화 방법에 대해 연구한다. 연구 결과를 바탕으로 촬영된 실사 영상은 디지털 사이니지와 같은 고해상도 영상 상영이 가능한 플랫폼에서 실감영상 구현이 가능할 것이라 기대한다. The multi-screen image system could make the audiences appreciate contents without special devices by expansively composing the images played on a single screen to many facets suitable for the use, which could provide the great immersiveness to the audiences. Based on the recent interest in realistic images, it is produced as films through the multi-projection technology such as Screen X or Escape, and it is developed into the media that could deliver stories and information. Also, the size of display tends to gradually get larger while the image quality is improved to high definition. Thus, the development is accelerated in the form of Digital Signage that could play the high definition image contents by solidly composing many HD or UHD display screens. Moreover, through the convergence of digital technologies, it is developed into the higher value-added industry that could have two-way communication. This study aims to understand the developmental history of multi-screen image from 1950 to the present, technical analysis, and the production method, and then to research how to minimize the image degradation when playing the contents, in various platforms using the multi-screen image.

        • SCOPUSKCI등재

          서로 다른 이중에너지 방사선흡수기계 기종 (Hologic QDR 4500-A 와 Lunar EXPERT-XL)간의 골밀도 교차 보정

          문대혁,김기수,이희경,김재승,신중우,조진만,김상욱 대한핵의학회 1999 핵의학 분자영상 Vol.33 No.3

          Purpose: A cross-calibration equation is needed to compare bone mineral density measured by different dual X-ray absoptiometry systems. We performed this study to establish appropriate cross-calibration equations between two different dual X-ray absorptiometry systems. Materials and Methods: Bone mineral density of anterior-posterior lumbar spine (L2-4 level) and femoral neck were measured in 109 women (55±11yr) using two different dual X-ray absorptiometry systems (Lunar EXPERT-XL) and Hologic QDR 4500-A). Bone mineral density values measured by two systems, including area, bone mass content, bone mineral density and percentile of young normals were compared and cross-calibration equations between two systems derived. Results: The bone mineral density values of 109 women measured by Lunar system were 0.958±0.17 g/cm2 at L2-4 and 0.768±0.131 g/cm2 at femur neck, which were significantly higher (13±6% at L2-4 and 19±7% at femur neck, p<0.001) than those (0.851±0.144 g/cm2 at L2-4 and 0.649±0.108 g/cm2 a neck) by Hologic system. Bone mineral content and percentile of young normals measured by Lunar system were also significantly higher than those by Hologic system (p<0.001), whereas there was no difference in area (p>0.05). There was a high correlation between bone mineral density values of L2-4 and femoral neck obtained with both dual X-ray absortiometry systems (r=0.96 and 0.95, respectively). Cross-calibration equations relating the bone mineral density were Lunar=1.1287×Hologic-0.0027 for L2-4 and Lunar=l.1556×Hologic+0.0l82 for femoral neck. Conclusion: We obtained cross-calibration equations of bone mineral density between Lunar EXPERT-XL and Hologic QDR 4500-A. These equations can be useful in comparing bone mineral density obtained by different dual X-ray absorptiometry systems.

        • SCOPUSKCI등재
        • SCOPUSKCI등재

          [I - 123] IPT SPECt를 이용한 정상인과 파킨슨환자의 도파민 운반체의 영상화 및 단순화된 정량분석 방법들의 비교연구

          문대혁,류진숙,양승오,이희경,김희중,천준홍,임주혁,봉정균,남기표,권수일 대한핵의학회 1996 핵의학 분자영상 Vol.30 No.3

          The purpose of this study was to compare the specific binding ratio method with model based methods in estimating the transporter parameter k3/k4 in normal controls and Parkinson's patients with [I-123]IPT SPECT and to evaluate the usefulness of [I-123]IPT SPECT. 6.5±1.1 mCi (239.0±40.3 MBq) of [123]IPT was intravenouly injected as a bolus into six normal controls(age:45±13) and seventeen patients(age:55±8) with Pakinson's disease(PD). The transporter parameter k3/k4 was derived using the Ichise's graphical method(Rv) and Lassen's area ratio method(RA) for the dynamic IPT SPECT data without blood samples. Then, the relationships between the transporter parameter Rv, RA and the ratio of (BG-OCC)/OCC at 115 minutes were evaluated by linear regression analysis. Rvs by Ichise's graphical method for NC and PD were 2.08±0.29 and 0.78±0.31, respectively. RAs by Lassen's area ratio method for NC and PD were 1.48±0.16 and 0.65±0.24, respectively. The correlation coefficients between (BG-OCC)/OCC and Rv, (BG-OCnd RA, and RV, and RA were 0.93, 0.90, 0.99 and their corresponding slopes were 0.54, 0.34, and 0.65,respectively. The Rv and RA of NC were significantly higher than the ones of PD. That is, the k3/k4 Of NC was clearly separated from the one of PD. k3/k4 showed a good correlation with the ratio of (BG-OCC)/OCC. The results indicate that the noninvasive simplified quantitative methods may be useful to measure the transporter parameter k3/k4 and the specific binding ratio method can be used for quantitative studies of dopamine transporter with [I-123]IPT SPECT in humans brains.

        • SCOPUSKCI등재

          신장 이식후에 발생한 무혈관성 골괴사 : 발생 빈도 및 골 SPECT의 유용성에 관하여 Prevalence and Usefulness of Bone SPECT

          문대혁,류진숙,양승오,최윤영,이희경 대한핵의학회 1995 핵의학 분자영상 Vol.29 No.4

          Avascular necrosis(AVN) of bone can be resulted from various causes that distrub vascular supply to bone tissue, includinrg steroid therapy after renal transplantation. In this study, we determine the prevalence of the avascular necrosis of bone after renal transplantation and compare the role of the bone scan, SPECT and MRI. In 301 patients with transplanted kidney, the prevalence of avascular necrosis was determined clinically. Site of bone necrosis was evaluated by clinical symptom, bone scan, SPECT and MRI. Bone scan was done in all patients with AVN. Bone SPECT and MRI were done in six cases; and MRI was done in two cases. The prevalence of AVN was 3.3% (10/301), and the site of AVN was 16 femoral heads in 10 patients (bilateral: 60%) and bilateral calcaneal tuberosity in one patient. Bone scan showed typical AVN (cold area with surrounding hot uptake) in 13 lesions, only hot uptake in three lesions (including two calcaneal tuberosities), decreased uptake in one lesion, and normal in one lesion. Decreased uptake and normal lesion showed an equivacal cold area without surrounding hot uptake on SPECT. A symptomatic patient with positive bone SPECT showed normal finding on MRI. The prevalence of AVN of bone after renal transplantation was 3.3%, and whole body bone scan showed multiple bone involvement. Two symptomatic hip joints without definite lesion on whole body bone scan or MRI showed cold defect on SPECT. Threfore, we conclude that bone SPECT should be perfomed in a symptomatic patient with negative bone scan or MRI in case with high risk of AVN after renal transplantation.

        • KCI등재

          저속촬영 기반의 초고화질 다면 영상 구현

          문대혁 한국디지털콘텐츠학회 2019 한국디지털콘텐츠학회논문지 Vol.20 No.8

          다양한 실감 영상 중 Screen X와 같은 다면영상은 와이드 영상의 한계를 넘어 3면 이상으로 구성된 화면을 통해 관객들에게 특별한 장치 없이 스토리를 전달하는 실감영상으로 색다른 몰입 감을 제공하고 있다. 그러나 이러한 다면영상은 화면 왜곡 현상, 스티칭 작업의 한계, 복잡한 시스템 환경 등으로 많은 영상 제작자들이 접근하기 어려운 제작 방법 중 하나이다. 이번 연구는 DSLR카메라를 이용한 타임랩스 영상을 Screen X와 같은 다면 영상 시스템에서 상영 가능한 가로 11,520 픽셀과 세로 2,160픽셀의 화면 종횡비가 5.3:1의 초고화질 3면 영상 콘텐츠 제작을 위한 화면 구성 및 제작 가이드라인을 제안하고자 한다. 이번 연구를 통해 Screen X와 같은 다면영상시스템이 대중화된 매체로 자리 잡아 관객들에게 다른 차원의 실감영상 감상을 몰입하게 만들 것이다. Multifaceted images such as Screen X among various real feeling images provide immersion with real feeling images that convey stories without special devices to audiences through three sided screens beyond the limit of wide screen. However, these multifaceted images are one of the difficult producing methods that video producers can't easily access due to screen distortion phenomena, limit of stitching work and complicated system environment. This study is intended to present the guidelines of screen organization and producing to make three sided image contents with 11,520 pixel width, 2,160 length and 5.3:1 screen aspect ratio ultra high definition that time lapse videos with the use of DSLR cameras can be played in multifaceted images like Screen X. Based on the results acquired through this research, it was expected that multi-image systems such as Screen X can be recognized as a popular medium capable of providing audiences with a sense of immersion in the process of appreciating different-dimensional realistic images.

        • KCI등재

          실감영상 구현을 위한 다면영상 정합보정 및 화면구성에 대한 연구

          문대혁 한국디지털정책학회 2017 디지털융복합연구 Vol.15 No.12

          Realistic videos using multi-view videos are created so that the contents shown on multi-view displays or screens look realistic. These images have been mostly used for special videos for exhibition, but, recently, systems such as Screen X have given rise to multi-view images as a format for storytelling contents such as movies. This study used HD-level broadcasting digital video camera with three zoom lenses for shooting wide to close-up shots focusing on a person, in the same way as Screen X, and identified and analyzed problems found during multi-view image registration correction. The results of this study suggested, provided the shooting technique and equipment are improved, the multi-view format can be used for conveying stories and information. Future research will need to investigate and supplement relevant techniques that will enable production of high-quality multi-view image contents by using a cinema-grade camera with standard lenses, instead of using broadcasting-grade zoom lenses. 다면영상을 이용한 실감영상은 스크린이나 다면으로 구성된 디스플레이에서 펼쳐지는 내용이 사실적으로 보여 지게 제작되어지고 있다. 이러한 다면영상은 전시를 위한 기획영상에서 주로 사용되었으나 Screen X와 같은 시스템을 통해 영화와 같은 스토리를 전달할 수 있는 포맷으로 재조명 되고 있다. 이번 연구는 3대의 줌렌즈가 장착된 HD급 방송용 디지털 비디오를 이용해 Screen X와 같은 방법으로 인물을 중심으로 한 전경 장면부터 클로즈업 장면까지 촬영한 후 다면영상 정합보정을 통해 발생되는 문제점을 분석 파악하였다. 촬영 방법과 장비를 보완하면 다면영상이란 포맷이 스토리와 정보 전달이 가능한 매체임을 제시하였고 향후 방송용 줌렌즈를 이용한 촬영보다 표준렌즈 기반의 시네마급 카메라를 이용한 양질의 다면영상 콘텐츠를 제작할 수 있도록 기술적 연구와 보완이 필요하다.

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