• Korean Journal of Digital Imaging in Medicine
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• v.3 no.1
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• pp.110-118
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• 1997

Recently, to make a diagnosis of the patient different X-Ray examinations are used. To name a few, Computed Tomography(CT). Magnetic Resonance Image(MRI) Single Photon Emission Computed Tomography(SPET) and Positron Emission Tomography(PET). But diagnosticians face difficulties sometimes when they make a diagnosis with images from those examinations. One of the problem is whether the Lesions of the patient is captured in the image correctly. Another one is whether the images are taken with same angle. in this paper, a study 9 on the method to obtain the hybrid image from the different images to different examinations. The procedure done in this paper is described as future study. Although small errors in position between images would occurred, this method more useful as it does not make patients in convenient. To reconstruct a image, some images are scanned by scanner and stored to personal computer for further image processing with Aldus photostyler program. The method to generate a sharpened image are also described.

• Journal of Chest Surgery
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• v.45 no.3
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• pp.189-191
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• 2012

Graft infections after aortic replacement are a rare, but severe complication. Because surgical removal of the infection source is essential, an accurate diagnosis is required to prevent unnecessary treatment. Both of the patients described herein were diagnosed with graft infections using dual-modality positron emission tomography-computed tomography; one patient was a false-positive, and the other was confirmed with an infection.

• Journal of Korean Neurosurgical Society
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• v.60 no.1
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• pp.98-101
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• 2017

We report a case of primary intracranial malignant melanoma (PIMM) with extracranial metastases. The patient was an 82-year-old woman diagnosed with PIMM under the left cerebellar tentorium. We performed a tumor resection followed by gamma knife surgery. An magnetic resonance imaging at 11 months after surgery showed a local intracranial recurrence. At 12 months, vertebral metastasis was suspected, and 2-[fluorine-18]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) showed multiple extracranial metastases. She died at 13 months after surgery. Although extracranial metastases of PIMM are extremely rare, we should carefully follow up extracranial metastases together with intracranial ones, especially by FDG-PET/CT, even at an early asymptomatic stage.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.10
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• pp.2563-2573
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• 1993

The measurements of monochromatic line-of-sight flame emission and light transmission in the same path having small spatial resolution were performed in an axisymmetric laminar propane $C_{3}H_{8}$ diffusion flame. The light wavelengthes of 632 nm, 800nm, 900nm were used. From these measurements, local point soot radiances (by Kirchhoff's law) and absorption coefficients were reconstructed by tomography. Thus local point soot temperatures and concentrations were obtained. The reconstructed soot temperatures and concentrations of local points have no differences between the case of visible range (632 nm) and the case of infrared range (800 nm and 900 nm). In these ranges, the scattering coefficient is much lower than the absorption coefficient. Soot mean temperature over the path also matches well with local soot temperature in outer region of the flame. Temperature measurement by thermocouple with different bead diameters $(222{\mu}m and 308{\mu}m)$ was carried in the same flame. Rapid insertion technique was used and radiation effect was considered. Radiation correction in the sooting region was carried out and the corrected result was in good agreement with the local soot temperature.

• The Journal of Engineering Research
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• v.2 no.1
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• pp.49-56
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• 1997

In emission computed tomography, statistical reconstruction methods in the context of a Bayesian framework have been a topic of interest over the last decade. This was mainly due to the fact that Bayesian approaches can incorporate a priori information into the reconstruction algorithm. Although these approaches can exhibit good performance, their applications to the clinic is hindered mainly by their high computational cost. On the other hand, the speed and simplicity of the filtered backprojection (FBP) algorithm have led to its widespread use in most clinical applications. In this work, we use spline models, which have been quite useful in Bayesian reconstruction, as regularizers for high-frequency apodization in FBP algorithm and show that the effects of using spline models as priors in Bayesian reconstruction can also be achieved in FBP reconstruction.

• Dementia and Neurocognitive Disorders
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• v.17 no.3
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• pp.90-99
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• 2018

Background and Purpose: To explore anatomic substrate of specific wandering patterns in patients with Alzheimer's disease (AD) by performing positron emission tomography with $^{18}F$ fluorodeoxyglucose positron emission tomography (FDG PET). Methods: Drug-naïve AD patients with wandering (n=80) and without wandering (n=262) were recruited. First, the specific pattern of wandering type was operationally classified according to specific wandering score and clinical assessment. Second, brain FDG PET was performed and fluorodeoxyglucose (FDG) uptake differences of specific brain regions according to wandering patterns were compared to those of non-wanderers. Results: In patients with pacing pattern, FDG PET showed significant lower FDG uptake in both middle cingulum and left putamen cluster compared to non-wanderers. The right precuneus and supplementary motor area in patients with random pattern and left calcarine sulcus, right calcarine sulcus, right middle cingulum, and right post central gyrus in patients with lapping pattern had significantly lower FDG uptake compared to non-wanderers. Conclusions: This study showed that wandering in patients with AD had three distinct patterns. These specific patterns showed significant lower FDG uptake in specific brain areas compared to non-wanderers.

• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2341-2347
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• 2021

Because single-photon emission computed tomography (SPECT) is one of the widely used nuclear medicine imaging systems, it is extremely important to acquire high-quality images for diagnosis. In this study, we designed a super-resolution (SR) technique using dense block-based deep convolutional neural network (CNN) and evaluated the algorithm on real SPECT phantom images. To acquire the phantom images, a real SPECT system using a^99mTc source and two physical phantoms was used. To confirm the image quality, the noise properties and visual quality metric evaluation parameters were calculated. The results demonstrate that our proposed method delivers a more valid SR improvement by using dense block-based deep CNNs as compared to conventional reconstruction techniques. In particular, when the proposed method was used, the quantitative performance was improved from 1.2 to 5.0 times compared to the result of using the conventional iterative reconstruction. Here, we confirmed the effects on the image quality of the resulting SR image, and our proposed technique was shown to be effective for nuclear medicine imaging.

• Nuclear Engineering and Technology
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• v.54 no.6
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• pp.1982-1990
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• 2022

The purpose of this study was to verify the possibility of fuel rod pattern analysis in a fresh fuel assembly using the Yonsei single-photon emission computed tomography (YSECT) system. The YSECT system consisted of three main parts: four trapezoidal-shaped bismuth germanate scintillator-based 64-channel detectors, a semiconductor-based multi-channel data acquisition system, and a rotary stage. In order to assess the performance of the prototype YSECT, tomographic images were obtained for three representative fuel rod patterns in the 6 × 6 array using two representative image-reconstruction algorithms. The fuel-rod patterns were then assessed using an in-house fuel rod pattern analysis algorithm. In the experimental results, the single-directional projection images for those three fuel-rod patterns well discriminated each fuel-rod location, showing a Gaussian-peak-shaped projection for a single 10 mm-diameter fuel rod with 12.1 mm full-width at half maximum. Finally, we successfully verified the possibility of the fuel rod pattern analysis for all three patterns of fresh fuel rods with the tomographic images obtained by the rotational YSECT system.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4591-4596
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• 2023

Single-photon emission computed tomography SPECT image reconstruction methods have a significant influence on image quality, with filtered back projection (FBP) and ordered subset expectation maximization (OSEM) being the most commonly used methods. In this study, we proposed newly-designed adaptive non-blind deconvolution with a structural similarity (SSIM) index that can take advantage of the FBP and OSEM image reconstruction methods. After acquiring brain SPECT images, the proposed image was obtained using an algorithm that applied the SSIM metric, defined by predicting the distribution and amount of blurring. As a result of the contrast to noise ratio (CNR) and coefficient of variation evaluation (COV), the resulting image of the proposed algorithm showed a similar trend in spatial resolution to that of FBP, while obtaining values similar to those of OSEM. In addition, we confirmed that the CNR and COV values of the proposed algorithm improved by approximately 1.69 and 1.59 times, respectively, compared with those of the algorithm involving an inappropriate deblurring process. To summarize, we proposed a new type of algorithm that combines the advantages of SPECT image reconstruction techniques and is expected to be applicable in various fields.

• Journal of Biomedical Engineering Research
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• v.31 no.4
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• pp.259-268
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• 2010

Breast cancer is the most prevalent woman cancer, and its prevalence rate is increasing rapidly. It is necessary to develop the breast-dedicated positron emission tomography (PET) or positron emission mammography (PEM) systems with high resolution and sensitivity to improve the accuracy of diagnosis of breast cancer. Therefore, it is necessary to develop the high-end PET system technologies, such as the measurement of depth-of-interaction (DOI) and fully digitalized data acquisition, to establish high performance breast imaging systems. In this paper, recent technical advances in breast-dedicated PET imaging systems will be reviewed.