• Nuclear Medicine and Molecular Imaging
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• 제42권1호
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• pp.1-7
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• 2008

PET allows non-invasive, quantitative and repetitive imaging of biological function in living animals. Small animal PET imaging with $[^{18}F]$FDG has been successfully applied to investigation of metabolism, receptor-ligand interactions, gene expression, adoptive cell therapy and somatic gene therapy. Experimental condition of animal handling impacts on the biodistribution of $[^{18}F]$FDG in small animal study. The small animal PET and CT images were registered using the hardware fiducial markers and small animal contour point. Tumor imaging in small animal with small animal $[^{18}F]$FDG PET should be considered fasting, warming, and isoflurane anesthesia level. Registered imaging with small animal PET and CT image could be useful for the detection of tumor. Small animal experimental condition of animal handling and registration method will be of most importance for small lesion detection of metastases tumor model.

• 대한의용생체공학회:의공학회지
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• 제26권1호
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• pp.43-47
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• 2005

We have developed a small bore x-ray CT for small animal imaging with a linear x-ray detector array and small-scale slip rings. The linear x-ray detector array consists of 1024 elements of 400□m×400□m with a gadolinium oxysulfide (GOS) scintillator on top of them. To avoid use of expensive large diameter slip rings for projection data transmission from the X­ray detector to the image reconstruction system, we used the wireless LAN technology. The projection data are temporally stored in the data acquisition system residing on the rotating gantry during the scan and they are transmitted to the image reconstruction system after the scan. With the wireless LAN technology, we only needed to use small-scale slip rings to deliver the AC electric power to the X-ray generator and the power supply on the rotating gantry. The performances of the small animal CT system, such as SNR, contrast, and spatial resolution, have been evaluated through experiments using various phantoms. It has been experimentally found that the SNR is almost linearly proportional to the tube current and tube voltage, and the minimum resolvable contrast is less than 30 CT numbers at 40kVp/3.0㎃. The spatial resolution of the small animal CT system has been found to be about 0.9Ip/㎜. Postmortem images of a piglet is also presented.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2019년도 춘계학술대회
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• pp.151-152
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• 2019

본 논문에서는 동물 이미지 분류를위한 작은 데이터 세트를 기반으로 개선 된 심층 학습 방법을 제안한다. 첫째, CNN은 소규모 데이터 세트에 대한 교육 모델을 작성하고 데이터 세트를 사용하여 교육 세트의 데이터 세트를 확장하는 데 사용된다. 둘째, VGG16과 같은 대규모 데이터 세트에 사전 훈련 된 네트워크를 사용하여 작은 데이터 세트의 병목을 추출하여 새로운 교육 데이터 세트 및 테스트 데이터 세트로 두 개의 NumPy 파일에 저장하고, 마지막으로 완전히 연결된 네트워크를 새로운 데이터 세트로 학습한다.

• Nuclear Medicine and Molecular Imaging
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• 제41권1호
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• pp.42-48
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• 2007

목적: 이 연구에서는 폐 전이 종양을 영상화하기 위하여 흑색종의 폐 전이 종양 마우스 모델을 제작하고 영상 획득 전처리 조건을 개선하여 폐 전이 종양의 $[^{18}F]FDG$ 소동물 PET 영상을 획득하고자 하였으며, 임상 CT를 이용하여 전이 종양의 해부학적 위치를 확인하고자 하였다. 대상 및 방법: 정상 마우스의 $[^{18}F]$FDG 영상 획득 전 조건은 $16{\sim}22$시간 금식 하고 $30^{\circ}C$의 온도를 유지하며 $[^{18}F]FDG$ (7.4 MBq) 정맥 주사 후 서로 다른 마취제(Ketamine/Xylazine, Ke/Xy과 Isoflurane, Iso)로 $[^{18}F]FDG$ 섭취 60분 동안 유지한 후 20분간 $[^{18}F]FDG$ 소동물 PET 영상을 획득하였다. 혈중 포도당 농도를 보정한 포도당 표준 섭취 계수 영상을 이용하여 관심영역 대 배경비(lung to background ratio, L/B)를 구하여 평가하였다. C57BL/6 마우스에 B16-F10 세포를 정맥내 주사하여 제작한 폐전이 종양 마우스 모델은 정상 마우스의 영상 획득 조건과 동일한 조건에서 $[^{18}F]FDG$ 소동물 PET 영상을 획득하였으며, 임상 CT를 이용하여 획득된 해부학적 영상으로 폐 부위의 종양 위치를 확인하였다. 결과: 정상 마우스의 평균 혈중 포도당 농도는 Ke/Xy으로 마취한 군에서 $128.0{\pm}23.87\;mg/dL$이었으며 Iso으로 마취한 군에서는 $86.0{\pm}21.65\;mg/dL$로, Ke/Xy으로 마취한 군이 Iso로 마취한 군 보다 1.5 배 높은 혈중 포도당 농도를 나타내었다. 포도당 표준 섭취 계수 영상에서의 L/B는 Ke/Xy으로 마취한 군에서 $8.6{\pm}0.48$ 이었으며 Iso으로 마취한 군에서는 $12.1{\pm}0.63$로, Iso로 마취한 군이 Ke/Xy으로 마취한 군 보다 주변 정상조직과의 대조도가 높은 경향을 보였다. 폐 전이 종양 마우스에서는 Iso로 마취한 군이 Ke/Xy으로 마취한 군의 $[^{18}F]FDG$ 소동물 PET 영상보다 주변 조직의 $[^{18}F]FDG$ 섭취가 낮았다. 또한 해부학적 종양의 위치를 확인하기 위하여 임상 CT 영상과 융합한 결과 폐 전이 종양이 폐 부위에 위치함을 확인하였다. 결론: 마우스와 같은 소동물에서의 폐 부위 종양을 $[^{18}F]FDG$로 영상화하는데 있어서 금식, 온도유지, $[^{18}F]FDG$ 섭취 시간 동안의 마취제 조건 등을 고려하여야 하며, $[^{18}F]FDG$ 소동물 PET과 CT 영상의 융합은 폐 부위의 전이 종양을 확인하는데 유용할 것으로 기대된다.

• 센서학회지
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• 제21권4호
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• pp.270-275
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• 2012

In this study, we have developed a mobile-based visible/NIR(Near InfraRed) imaging equipment for the animal testing. This equipment can provide visible, NIR and merged image through the viewer program. Especially, merged image help researcher to understand visual messages at animal in-vivo test. Also, it is available to send real-time images through the smart phone. Researcher can communicate with another researcher who is a long distance away. Also, the equipment was made with portable small size to enable it to commercialize.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2019년도 제59차 동계학술대회논문집 27권1호
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• pp.123-124
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• 2019

This paper proposes an improved deep learning method based on small data sets for animal image classification. Firstly, we use a CNN to build a training model for small data sets, and use data augmentation to expand the data samples of the training set. Secondly, using the pre-trained network on large-scale datasets, such as VGG16, the bottleneck features in the small dataset are extracted and to be stored in two NumPy files as new training datasets and test datasets. Finally, training a fully connected network with the new datasets. In this paper, we use Kaggle famous Dogs vs Cats dataset as the experimental dataset, which is a two-category classification dataset.

• 센서학회지
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• 제26권4호
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• pp.245-250
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• 2017

A novel method to implement a birdcage-type receiving coil sensor for use in a magnetic resonance imaging(MRI) system has been demonstrated employing a flexible printed circuit board (FPCB) fabrication technique. Unlike the conventional methods, the two-dimensional shape of the coil sensor is first implemented as a FPCB and then it is attached to the surface of a cylindrical supporting structure to implement the three-dimensional birdcage-type coil sensor. The proposed method is very effective to implement object-specific MRI coil sensors especially for small animal measurements in research and preclinical applications since the existing well-developed FPCB-based techniques can easily meet the requirements on accuracies and costs during coil implement process. The performances of the coil sensor verified through $^1H$ 1.5T MRI measurements for small animals and it showed excellent characteristics by providing a high spatial precision and a high signal-to-noise ratio.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2003년도 제27회 추계학술대회
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• pp.44-44
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• 2003

As a basic measurement tool in the areas of animal models of human disease, gene expression and therapy, and drug discovery and development, small animal PET imaging is being used increasingly. An ideal small animal PET should have high sensitivity and high and uniform resolution across the field of view to achieve high image quality. However, the combination of long narrow pixellated crystal array and small ring diameter of small animal PET leads to the degradation of spatial resolution for the source located at off center. This degradation of resolution can be improved by determining the depth of interaction (DOI) in the crystal and by taking into account the information in sorting the coincident events. Among a number of 001 identification schemes, dual layer phsowich detector has been widely investigated by many research groups due to its practicability and effectiveness on extracting DOI information. However, the effects of each crystal length composing dual layer phoswich detector on DOI measurements and image qualities were not fully characterized. In order to minimize the DOI effect, the length of each layer of phoswich detector should be optimized. The aim of this study was to perform simulations using a simulation tool, GATE to design the optimum lengths of crystals composing a dual layer phoswich detector. The simulated small PET system employed LSO front layer LuYAP back layer phoswich detector modules and the module consisted of 8${\times}$8 arrays of dual layer crystals with 2 mm ${\times}$ 2 mm sensitive area coupled to a Hamamatsu R7600 00 M64 PSPMT. Sensitivities and variation of radial resolutions were simulated by varying the length of LSO front layer from 0 to 10 mm while the total length (LSO + LuYAP) was fixed to 20 mm for 10 cm diameter ring scanner. The radial resolution uniformity was markedly improved by using DOI information. There existed the optimal lengths of crystal layers to minimize the variation of radial resolutions. In 10 cm ring scanner configuration, the radial resolution was kept below 3.4 mm over 8 cm FOV while the sensitivity was higher than 7.4% for LSO 5 mm : LuYAP 15 mm phoswich detector. In this study, the optimal length of dual layer phoswich detector was derived to achieve high and uniform radial resolution.

• 대한의용생체공학회:의공학회지
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• 제25권2호
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• pp.97-102
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• 2004

소 동물 촬영에 이용될 수 있는 고해상도의 x-선 cone-beam micro computed tomography (micro-CT) 시스템을 개발하였다 Micro-CT 시스템은 120${\times}$120 mm2 의 2차원 평판 x-선 감지기, micro-focus x-선 발생장치, 주사 기구부, 병렬처리 영상 재구성 시스템으로 이루어져 있다. 개발된 시스템의 성능을 평가하기 위해 대조도와 공간해상도를 측정하였다. 대조도 실험에서는 95 mGy 에서 36 CT-번호를 구별할 수 있음을 확인하였고, 공간 해상도 실험에서는 14 lp/mm 의 성능을 확인하였다. 소 동물 촬영 결과로 실험용 쥐의 대퇴부, 심장 그리고 복부 동맥 혈관을 촬영한 경상을 제시하였다. 개발된 micro-CT 시스템은 소 동물을 이용한 생명공학 분야 연구에 널리 이용될 수 있을 것으로 기대된다.

• 대한의용생체공학회:의공학회지
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• 제27권4호
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• pp.189-196
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• 2006

Micro computed tomography (micro-CT) has been used for in vivo animal study owing to its noninvasive and high spatial resolution capability. However, the sizes of existing detectors for micro-CT systems are too small to obtain whole-body images of a small animal object with $\sim$10 micron resolution and a part of its bones or other organs should be extracted. So, we have introduced the zoom-in micro-tomography technique which can obtain high-resolution images of a local region of an live animal object without extracting samples. In order to verify our zoom-in technique, we performed in vivo animal bone study. We prepared some SD (Sprague-Dawley) rats for making osteoporosis models. They were divided into control and ovariectomized groups. Again, the ovariectomized group is divided into two groups fed with normal food and with calcium-free food. And we took 3D tomographic images of their femurs with 20 micron resolution using our zoom-in tomography technique and observed the bone changes for 12 weeks. We selected ROI (region of interest) of a femur image and applied 2D FDT (fuzzy distance transform) to measure the trabecular bone thickness. The measured results showed obvious bone changes and big differences between control and ovariectomized groups. However, we found that the reliability of the measurement depended on the selection of ROI in a bone image for thickness calculation. So, we extended the method to 3D FDT technique. We selected 3D VOI (volume of interest) in the obtained 3D tomographic images and applied 3D FDT algorithm. The results showed that the 3D technique could give more accurate and reliable measurement.