• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.705-710
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• 1998

We describe a multigrid wavelet-based natural pixel (WNP) method for image reconstruction in emission computed tomography (ECT). The ECT is used to identify the tagged radioactive material's position in the body for detection of abnormal tissue such as tumor or cancer, as in SPECT and PET. With ECT methodology in parallel beam mode, we formulate a matrix-based reconstruction method for radionuclide sources in the human body. The resulting matrix for a practical problem is very large and nearly singular. To overcome this ill-conditioning, wavelet transform is considered in this study. Wavelets have inherent de-noising and multiscale resolution properties. Therefore, the multigrid wavelet-based natural pixel (WNP) method is very efficient to reconstruct image from projection data that is noisy and incomplete. We test this multigrid wavelet natural pixel (WNP) reconstruction method with the MCNP generated projection data for diagnosis of the simulated cancerous tumor.

• 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.

• Radiation Oncology Journal
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• v.29 no.3
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• pp.214-217
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• 2011

To avoid improper tumor volume contouring in radiation therapy (RT) and other invasive procedures, we report a case of uterine adenomyosis showing increased $^{18}F$-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET)/computed tomography (CT) mimicking malignant tumor in a 44-year-old woman during concurrent chemoradiation therapy (CCRT) for uterine cervical cancer. The adenomyosis was not associated with her menstrual cycle or with normal endometrium uptake, and it resolved one month after completion of RT. This case indicates that uterine adenomyosis in a premenopausal woman may show false positive uptake of $^{18}FDG$-PET/CT associated with CCRT.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.2
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• pp.118-126
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• 2008

Statistical image reconstruction methods have played an important role in emission computed tomography (ECT) since they accurately model the statistical noise associated with gamma-ray projection data. Although the use of statistical methods in clinical practice in early days was of a difficult problem due to high per-iteration costs and large numbers of iterations, with the development of fast algorithms and dramatically improved speed of computers, it is now inevitably becoming more practical. Some statistical methods are indeed commonly available from nuclear medicine equipment suppliers. In this paper, we first describe a mathematical background for statistical reconstruction methods, which includes assumptions underlying the Poisson statistical model, maximum likelihood and maximum a posteriori approaches, and prior models in the context of a Bayesian framework. We then review a recent progress in developing fast iterative algorithms.

• Imaging Science in Dentistry
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• v.44 no.4
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• pp.325-332
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• 2014

A combination of positron emission tomography (PET) with $^{18}F$-labeled fluoro-2-deoxyglucose ($^{18}F$-FDG) and computed tomography ($^{18}F$-FDG-PET/CT) has increasingly become a widely used imaging modality for the diagnosis and management of head and neck cancer. On the basis of both recent literature and our professional experience, we present a set of principles with pictorial illustrations and clinical applications of FDG-PET/CT in the evaluation and management planning of squamous cell carcinoma of the oral cavity and oropharynx. We feel that this paper will be of interest and will aid the learning of oral and maxillofacial radiology trainees and practitioners.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.5
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• pp.505-507
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• 2009

A 60-year-old woman, who had non-small-cell lung cancer (NSCLC) in left lower lobe underwent brain F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for evaluation of cerebral metastasis. On follow-up FDG-PET/CT, only hypometaolic lesion was detected and progressed in right frontal lobe at 6 months and 10 months, later. Hypermetabolic metastasis was not detected even at last scan time of FDG-PET/CT. Brain MRI showed brain metastasis in right frontal lobe. As might be expected, the physician should take cerebral metastasis into consideration even though there is only hypometabolic change on subsequent FDG-PET/CT in patients with NSCLC.

• Imaging Science in Dentistry
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• v.36 no.2
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• pp.111-116
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• 2006

PET/CT is a new imaging technology that combines high-quality Positron Emission Tomography (PET) and Computed Tomography (CT). This imaging provides simultaneous anatomical and metabolic information. Therefore PET/CT is useful diagnostic modality for early detection of malignant tumor, accurate staging, decision on therapeutic plan, monitoring response to therapy and rapid detection of recurrence. We report oral and maxillofacial cancers diagnosed by using PET/CT and the usefulness of PET/CT in the evaluation of postoperative recurrence.

• Journal of the Korean Society of Combustion
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• v.4 no.1
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• pp.105-115
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• 1999

The structure of a non-axisymmetric propane diffusion flame was investigated. Tomographic reconstruction method to convert the line-integrated self-emission data of a fuel-rich diffusion flame with square cross-section was applied to get the spatially reconstructed emission data. Modified Shepp-Logan filter and concentric squares raster were chosen for reconstructing arbitrarily shaped object in this process. Spatially reconstructed emission data were then interpreted to several physical quantities, such as flame edge, FWHM, perimeter and 3-D flame temperature distribution. Necessary assumptions were discussed and the results were interpreted. In comparison with axisymmetric flame, flame edge was developed higher, and sooting region of upstream was broader than in this non-axisymmetric one. At some height, the flame was shrunk very rapidly and finally formed circular cross-section.

• 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.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.10a
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• pp.346-346
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• 1998