• 제목/요약/키워드: Resolution recovery

검색결과 187건 처리시간 0.028초

Gold Beads Implants for The Treatment of Canine Chronic Recurrent Otitis Externa

  • Sumano, Hector;Tapia-Perez, Graciela;Gutierrez, Lilia
    • 한국임상수의학회지
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    • 제30권2호
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    • pp.100-106
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    • 2013
  • A clinical trial was performed to assess clinical efficacy and/or reduction in relapses by gold-bead implantation into acupuncture points in dogs with canine chronic recurrent otitis externa (CCROE). Forty dog-patients randomly divided into two groups were diagnosed as suffering CCROE, having intact tympanic membranes and a history of recurrences. Treatments were: control group (CG), treated with commercially available antimicrobial otic droplets, dosed twice daily for 7 days; and experimental group (GBI- gold bead implants), treated as for CG plus the insertion of 13 gold-bead implants under light anesthesia. Overall per cent assessment of composite clinical progression and progression of individual clinical signs were recorded. Bilateral chronic external otitis was diagnosed in 60% of the cases and left or right otitis in 20% of the cases each. Logistic model for repeated measures analysis showed that GBI induced a better clinical recovery as far as lesion score of some clinical signs is concerned. The overall percent cures of each group showed statistically significant difference. A McNemar analysis revealed that higher number of relapses was observed in CG patients as compared to the GBI (P < 0.05). In particular during these days, lesion on the pinna showed in odd ratios analysis a 7:1 ratio (recurrence CG:GBI) and ear wax/pus (4:1) from D42 to D365. It is concluded that gold-bead implantation into acupuncture points improves resolution of some clinical signs and greatly reduce relapses in CCROE affected dogs after 1 year follow-up (98.75%).

Analytic simulator and image generator of multiple-scattering Compton camera for prompt gamma ray imaging

  • Kim, Soo Mee
    • Biomedical Engineering Letters
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    • 제8권4호
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    • pp.383-392
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    • 2018
  • For prompt gamma ray imaging for biomedical applications and environmental radiation monitoring, we propose herein a multiple-scattering Compton camera (MSCC). MSCC consists of three or more semiconductor layers with good energy resolution, and has potential for simultaneous detection and differentiation of multiple radio-isotopes based on the measured energies, as well as three-dimensional (3D) imaging of the radio-isotope distribution. In this study, we developed an analytic simulator and a 3D image generator for a MSCC, including the physical models of the radiation source emission and detection processes that can be utilized for geometry and performance prediction prior to the construction of a real system. The analytic simulator for a MSCC records coincidence detections of successive interactions in multiple detector layers. In the successive interaction processes, the emission direction of the incident gamma ray, the scattering angle, and the changed traveling path after the Compton scattering interaction in each detector, were determined by a conical surface uniform random number generator (RNG), and by a Klein-Nishina RNG. The 3D image generator has two functions: the recovery of the initial source energy spectrum and the 3D spatial distribution of the source. We evaluated the analytic simulator and image generator with two different energetic point radiation sources (Cs-137 and Co-60) and with an MSCC comprising three detector layers. The recovered initial energies of the incident radiations were well differentiated from the generated MSCC events. Correspondingly, we could obtain a multi-tracer image that combined the two differentiated images. The developed analytic simulator in this study emulated the randomness of the detection process of a multiple-scattering Compton camera, including the inherent degradation factors of the detectors, such as the limited spatial and energy resolutions. The Doppler-broadening effect owing to the momentum distribution of electrons in Compton scattering was not considered in the detection process because most interested isotopes for biomedical and environmental applications have high energies that are less sensitive to Doppler broadening. The analytic simulator and image generator for MSCC can be utilized to determine the optimal geometrical parameters, such as the distances between detectors and detector size, thus affecting the imaging performance of the Compton camera prior to the development of a real system.

C-arm CT의 필수 성능평가 기준 마련을 위한 연구 (A Study on Establishment of Essential Performance Evaluation Criteria for C-arm Computed Tomography)

  • 김은혜;박혜민;김정민
    • 대한방사선기술학회지:방사선기술과학
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    • 제45권2호
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    • pp.127-134
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    • 2022
  • In order to overcome the image quality limitations of the conventional C-arm, a flat panel detector (FPD) is used to enhance spatial resolution, detective quantum efficiency, frame rate, and dynamic range. Three-dimensional (3D) visualized information can be obtained from C-arm computed tomography (CT) equipped with an FPD, which can reduce patient discomfort and provide various medical information to health care providers by conducting procedures in the interventional procedure room without moving the patient to the CT scan room. Unlike a conventional C-arm device, a C-arm CT requires different basic safety and essential performance evaluation criteria; therefore, in this study, basic safety and essential performance evaluation criteria to protect patients, medical staff, and radiologists were derived based on International Electrotechnical Commission (IEC) standards, the Ministry of Food and Drug Safety (MFDS) standards in Korea, and the rules on the installation and operation of special medical equipment in Korea. As a result of the study, six basic safety evaluation criteria related to electrical and mechanical radiation safety (leakage current, collision protection, emergency stopping device, overheating, recovery management, and ingress of water or particulate matter into medical electrical (ME) equipment and ME systems: footswitches) and 14 essential performance evaluation criteria (accuracy of tube voltage, accuracy of tube current, accuracy of loading time, accuracy of current time product, reproducibility of radiation output, linearity and consistency in radiography, half layer value in X-ray equipment, focal size and collimator, relationship between X-ray field and image reception area, consistency of light irradiation versus X-ray irradiation, performance of the mechanical device, focal spot to skin distance accuracy, image quality evaluation, and technical characteristic of cone-beam computed tomography) were selected for a total of 20 criteria.

Clinical Features of Fracture versus Concussion of the Temporal Bone after Head Trauma

  • Kong, Tae Hoon;Lee, Jae Woo;Park, Yoon Ah;Seo, Young Joon
    • Journal of Audiology & Otology
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    • 제23권2호
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    • pp.96-102
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    • 2019
  • Background and Objectives: Temporal bone fracture (TBF) is a common occurrence in cases of head trauma. Although the incidence of temporal bone concussion (TBC) has increased in cases of head trauma, it has not been extensively studied. We assessed the characteristics of TBF and TBC in patients with head trauma. Subjects and Methods: We conducted a retrospective review of 432 patients with head injury who visited our hospital between January 2011 and April 2016. Of these patients, 211 who met the inclusion criteria were included in the study. Their clinical characteristics, causes of injury, and hearing function were analyzed. Results: Among the 211 patients, 157 had TBFs and 54 had TBCs. Ear symptoms were more common among patients with TBF than among those with TBC. Car accidents were the most common cause of both TBF and TBC, but assault and sports injuries were more common among patients with TBC than among those with TBF. The occurrence of facial palsy in both cases of TBF and TBC. Hearing loss was observed among 35 patients with TBF and 11 patients with TBC. However, patients with TBF showed conductive hearing loss with an air-bone gap. Hearing function of these patients with TBF recovered with a reduced air-bone gap, but the patients with TBC showed little recovery. Conclusions: Emergency physicians should focus more on temporal bone injury in patients with head trauma. Therefore, an early complete diagnostic battery, which includes high-resolution computed tomography, audiometric tests, neurologic examination, and vestibular tests, be performed in patients with head trauma.

Clinical Features of Fracture versus Concussion of the Temporal Bone after Head Trauma

  • Kong, Tae Hoon;Lee, Jae Woo;Park, Yoon Ah;Seo, Young Joon
    • 대한청각학회지
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    • 제23권2호
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    • pp.96-102
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    • 2019
  • Background and Objectives: Temporal bone fracture (TBF) is a common occurrence in cases of head trauma. Although the incidence of temporal bone concussion (TBC) has increased in cases of head trauma, it has not been extensively studied. We assessed the characteristics of TBF and TBC in patients with head trauma. Subjects and Methods: We conducted a retrospective review of 432 patients with head injury who visited our hospital between January 2011 and April 2016. Of these patients, 211 who met the inclusion criteria were included in the study. Their clinical characteristics, causes of injury, and hearing function were analyzed. Results: Among the 211 patients, 157 had TBFs and 54 had TBCs. Ear symptoms were more common among patients with TBF than among those with TBC. Car accidents were the most common cause of both TBF and TBC, but assault and sports injuries were more common among patients with TBC than among those with TBF. The occurrence of facial palsy in both cases of TBF and TBC. Hearing loss was observed among 35 patients with TBF and 11 patients with TBC. However, patients with TBF showed conductive hearing loss with an air-bone gap. Hearing function of these patients with TBF recovered with a reduced air-bone gap, but the patients with TBC showed little recovery. Conclusions: Emergency physicians should focus more on temporal bone injury in patients with head trauma. Therefore, an early complete diagnostic battery, which includes high-resolution computed tomography, audiometric tests, neurologic examination, and vestibular tests, be performed in patients with head trauma.

인벤토리 기반 농촌지역 홍수손실 평가기법 개발 (Development of an Inventory-Based Flood Loss Estimation Method for Rural Areas)

  • 김시내;이종혁;전상민;최원;강문성
    • 한국농공학회논문집
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    • 제65권6호
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    • pp.65-78
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    • 2023
  • In recent times, the frequency and intensity of natural disasters, such as heavy rains and typhoons, have been increasing due to the impacts of climate change. This has led to a rise in social and economic damages. Rural areas, in particular, possess limited disaster response capabilities due to their underdeveloped infrastructure and are highly vulnerable to flooding. Therefore, it is crucial to establish preventative and responsive measures. In this study, an Inventory-Based Flood Loss Estimation (IB-FLE) method utilizing high-resolution spatial information was developed for estimating flood-related losses in rural areas. Additionally, the developed approach was applied to a study area and compared with the Multidimensional Flood Damage Analysis (MD-FDA) method. Compared to the MD-FDA, the IB-FLE enables faster and more accurate estimation of flood damages and allows for the assessment of individual building and agricultural land losses using up-to-date information. The findings of this study are expected to contribute to the rational allocation of budgets for rural flood damage prevention and recovery, as well as enhancing disaster response capabilities.

Structural evaluation of degradation products of Loteprednol using LC-MS/MS: Development of an HPLC method for analyzing process-related impurities of Loteprednol

  • Rajesh Varma Bhupatiraju;Bikshal Babu Kasimala;Lavanya Nagamalla;Fathima Sayed
    • 분석과학
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    • 제37권2호
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    • pp.98-113
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    • 2024
  • The current investigation entails the characterization of five degradation products (DPs) formed under different stress conditions of loteprednol using liquid chromatography-tandem mass spectrometry (LC-MS/MS). In addition, this study developed a stable high-performance liquid chromatography (HPLC) method for evaluating loteprednol along with impurities. The method conditions were meticulously fine-tuned which involved the exploration of the appropriate solvent, pH, flow of the mobile phase, columns, and wavelength. The method conditions were carefully chosen to successfully resolve the impurities of loteprednol and were employed in subsequent validation procedures. The stability profile of loteprednol was exposed to stress degradation experiments conducted under five conditions, and DPs were structurally characterized by employing LC-MS/MS. The chromatographic resolution of loteprednol and its impurities along with DPs was effectively achieved using a Phenomenex Luna 250 mm C18 column using 0.1 % phosphoric acid, methanol, and acetonitrile in 45:25:30 (v/v) pumped isocratically at 0.8 mL/min with 243 nm wavelength. The method produces an accurate fit calibration curve in 50-300 ㎍/mL for loteprednol and LOQ (0.05 ㎍/mL) - 0.30 ㎍/mL for its impurities with acceptable precision, accuracy, and recovery. The stress-induced degradation study revealed the degradation of loteprednol under basic, acidic, and photolytic conditions, resulting in the formation of seven distinct DPs. The efficacy of this method was validated through LC-MS/MS, which allowed for the verification of the chemical structures of the newly generated DPs of loteprednol. This method was appropriate for assessing the impurities of loteprednol and can also be appropriate for structural and quantitative assessment of its degradation products.

A rapid separation of Cs, Sr and Ba using gas pressurized extraction chromatography with inductively coupled plasma-mass spectrometry

  • Sojin Jeong;Jihye Kim;Hanul Cho;Hwakyeung Jeong;Byungman Kang;Sang Ho Lim
    • 분석과학
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    • 제37권2호
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    • pp.123-129
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    • 2024
  • We present a rapid method for the determination of Cs, Sr, and Ba, heat generators found in highly active liquid wastes, by gas-pressurized extraction chromatography (GPEC) using a column containing a cation-exchange resin. GPEC is a microscale column chromatographic technique that uses a constant flow rate of solvent (0.07 mL/min) with pressurized nitrogen gas supplied through a valve. In particular, because this method uses a small sample volume (a few hundred microliters), it produces less chemical waste and allows for faster separation compared to traditional column chromatography. In this study, we evaluated the separation of Cs, Sr, and Ba using GPEC. The eluate from the column (GPEC or conventional column chromatography) was quantitatively analyzed using inductively coupled plasma-mass spectrometry to measure the column recovery and precision. The column reproducibility of the proposed GPEC system (RSDs of recoveries) ranged from 2.7 to 4.1 %, and the column recoveries for the three elements ranged from 72 to 98% when aqueous HCl was used as the eluent. The GPEC results are slightly different in efficiency and separation resolution compared to those of conventional column chromatography because of the differences in the eluent flow rate as well as the internal diameter and length of the column. However, the two methods had similar recoveries for Cs and Sr, and the precision of GPEC was improved by two-fold. Remarkably, the solvent volume required for GPEC analysis was five times lower than that of the conventional method, and the total analysis time was 11 times shorter.

감쇠보정, 산란보정 및 해상도복원이 정량적 심근 SPECT의 관상동맥질환 진단성능에 미치는 효과 (Effect of Attenuation Correction, Scatter Correction and Resolution Recovery on Diagnostic Performance of Quantitative Myocardial SPECT for Coronary Artery Disease)

  • 황경훈;이동수;팽진철;이명묵;정준기;이명철
    • 대한핵의학회지
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    • 제36권5호
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    • pp.288-297
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    • 2002
  • 목적: 심근 SPECT 영상의 재구성 과정에 감쇠보정, 산란보정 및 해상도복원 시스템(ASCRR)이 적용되었을 때 관상동맥질환 진단의 진단능 변화를 정량적 심근 SPECT에서 조사하였다. 대상 및 방법: 관상동맥질환이 의심되는 환자 75명과 관상동맥질환 저위험군 20명의 환자에 대하여 휴식기 Tl-201/부하기 Tc-99m-MIBI 게이트 심근 SPECT를 시행한 후, ASCRR을 적용하여 적용 전후의 예민도 및 특이도와 정상검출율의 변화를 구하였다. 결과: ASCRR 적용 후, 전반적인 진단능에는 유의한 변화가 없었다. 혈관 영역 별로는 좌전하행동맥(LAD)이나 좌회선동맥(LCX) 영역의 병변에서는 유의한 차이는 없었고, 우측관상동맥(RCA) 영역의 병변을 진단하는 데 있어서는 ASCRR의 적용 후 특이도는 유의하게 향상되었지만, 이와 더불어 예민도는 유의하게 감소되었다(모두 p<0.05). 정상검출율은 좌전하행동맥(LAD) 영역과 좌회선동맥(LCX) 영역에서는 ASCRR 적용 전후에 유의한 차이가 없었고, 우측관상동맥(RCA) 영역에서만 유의한 증가를 보여, 전반적으로는 통계적으로 유의한 차이가 없었다. 결론: 심근 SPECT에서 감쇠보정 및 산란교정, 그리고 해상도복원시스템의 적용은 관상동맥질환의 진단에 있어서 우측관상동맥(RCA) 영역의 정상검출율 및 특이도는 증가시키지만, 전반적인 진단능은 향상시키지 못한다.

충적층의 정밀 선구조 추출을 위한 위성영상과 GIS 기법의 활용에 관한 연구 (A Study on the Precise Lineament Recovery of Alluvial Deposits Using Satellite Imagery and GIS)

  • 이수진;석동우;황종선;이동천;김정우
    • 한국GIS학회:학술대회논문집
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    • 한국GIS학회 2003년도 공동 춘계학술대회 논문집
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    • pp.363-368
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    • 2003
  • Landsat TM 영상을 이용, 명암차가 높은 산악 지역에 적용해왔던 알고리즘을 개선하여 비교적 명암차가 낮고 충적층이 넓게 분포하는 지역의 선구조를 추출하는 알고리즘을 개발하였다. 수치지형모델에 대하여 Local Enhancement를 이용, 평탄한 지역으로부터 충적층을 추출하였다. Zevenbergen & Thorno's Method를 3×3moving windowing을 통해서 최대 경사방향과 경사를 이용하여 충적층을 지나는 선구조 요소를 추출하고 다시 Hough 변환을 이용해서 1차 선구조를 추출하였다. 이로부터 충적층의 직각방향의 지형단면의 경사를 유추해서 spline 보간법을 이용해 단면의 최저점을 구하고 이 구해진 점들을 다시 Hough 변환을 이용해서 최종 선구조를 추출하였다. 본 연구에서 사용한 알고리즘은 기존 알고리즘에서 사용된 소창문보다 훨씬 큰 충적층이 분포하는 지역의 지형 경사가 수렴하는 부분에 선구조가 뚜렷이 나타남을 볼 수 있다. 최대경사방향과 경사를 구해서 얻어진 1차 선구조와 최종선구조에서 선구조 방향이 다소 차이를 보인다. 1차 선구조의 수직방향 지형단면의 자료를 이용함에 있어, 지형 단면의 시작점과 끝지점을 임의적으로 결정하는 것이 아니라, 충적층을 가로질러 최고점까지 또는 다음 충적층이 나을 때까지의 자료를 이용해서 보간법을 사용하였고, 충적층의 넓이에 따라 보간할 자료량의 차이에 의한 오차가 발생할 수 있다. 넓은 충적층에서 선구조가 잘 추출되는 반면에 좁은 충적층이 분포하거나 계곡에 해당하는 지역에서는 경사수렴부와 일치하지 않는 선구조가 추출되었다. 이는 향후 계속적으로 연구해서 보완되어야 할 것으로 사료된다. 차원에서 기준치 설정 및 주기적인 측정을 통해 지속적으로 관리를 해야 한다. 그리고 정기적인 특수건강진단의 실시와 같은 근본적인 해결방안을 찾아야겠다.l rectangular type to a wed농e type. The Proposed wedge shape makes the absorption length longer for obliquely incident photons, thus increasing the detection efficiency and suppressing leakage coefficient. For the BGO detectors of 4-8mm width, the computer simulation result of the system using wedge detectors reveals resolution improvement to the system using conventional detectors. For the system composed of 200 BGO detectors of 8mm width with 2 point sampling motion, the simulation resolution system using conventional detectors. For the very high resolution system of 3-7mm FWHM, the characteristics of the detector shape and size is studied by computer simulation.n, but also such efficient a parameter as to perform almost like entropy.소한 1대

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