• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.523-530
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• 2019

The purpose of this study was to obtain the K-edge images using a spectral CT system based on a photon-counting detector and implement the 3D fusion imaging using the conventional and spectral CT images. Also, we evaluated the clinical feasibility of the 3D fusion images though the quantitative analysis of image quality. A spectral CT system based on a CdTe photon-counting detector was used to obtain K-edge images. A pork phantom was manufactured with the six tubes including diluted iodine and gadolinium solutions. The K-edge images were obtained by the low-energy thresholds of 35 and 52 keV for iodine and gadolinium imaging with the X-ray spectrum, which was generated at a tube voltage of 100 kVp with a tube current of $500{\mu}A$. We implemented 3D fusion imaging by combining the iodine and gadolinium K-edge images with the conventional CT images. The results showed that the CNRs of the 3D fusion images were 6.76-14.9 times higher than those of the conventional CT images. Also, the 3D fusion images was able to provide the maps of target materials. Therefore, the technique proposed in this study can improve the quality of CT images and the diagnostic efficiency through the additional information of target materials.

• Journal of radiological science and technology
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• v.41 no.3
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• pp.215-221
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• 2018

Cone beam Computed Tomography(CBCT) is an increasing trend in clinical applications due to its ability to increase the accuracy of radiation therapy. However, this leaded to an increase in exposure dose. In this study, the simulation using Monte Carlo method is performed and the absorbed dose of CBCT is analyzed and standardized data is presented. First, after simulating the CBCT, the photon spectrum was analyzed to secure the reliability and the absorbed dose of the tissue in the human body was evaluated using the MIRD phantom. Compared with SRS-78, the photon spectrum of CBCT showed similar tendency, and the average absorbed dose of MIRD phantom was 8.12 ~ 25.88 mGy depending on the body site. This is about 1% of prescription dose, but dose management will be needed to minimize patient side effects and normal tissue damage.

• Journal of the Korean Society of Radiology
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• v.15 no.3
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• pp.301-306
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• 2021

The use of tin filters as a way to reduce the medical radiation in computed tomography (CT). However, due to the changed X-ray spectrum with the use of tin filters, disease diagnosis could be affected because it appears as images of different impressions from previous images. Therefore, this study evaluates the changes in images when using tin filter and high pitch in chest low-dose CT. In this study, images were acquired in groups of three for comparison. Group 1 did not apply to tin filter, and used the existing pitch 0.8. Group 2 used a tin filter, pitch 0.8, Group 3 used a tin filter, and pitch 2.5. To compare the image quality, the natural image quality evaluator (NIQE) and the blind/referenceless image quality evaluator (BRISQUE) were used among the blind quality evaluation factors depended on a no-reference basis. As a result, the NIQE values were low in the order of Group 1, Group 3, and Group 2. BRISQUE values were low in the order of Group 3, Group 2 and Group 1. This study confirms the superiority of images of tin filter and high pitch techniques in chest low-dose CT, which is considered to be a fundamental study for acquiring accurate images of patients with difficult breathing control.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.8 no.2
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• pp.256-265
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• 1997

Objectives：The purpose of this study was to investigate the characteristics and differences of brain function in pervasive developmental disorder and developmental language disorder. Method：The subjects were composed of 14 cases of pervasive developmental disorder and 13 cases developmental language disorder. They were investigated by technitium-99m-EDC SPECT. All SPECT were visually assessed by two nuclear medicine specialists, and then quantified by region of interest including temporal, parietal cortex, thalamus, basal ganglia and cerebellum. Result：In both groups, cerebral blood flow was decreased in the temporal, parietal cortex, basal ganglia, thalamus, cerebellum by visual assessment. There was no significant difference between the 2 groups by quantitative and qualitative assessment. Conclusion：These results suggest that pervasive developmental disorder and developmental language disorder are caused by defects in the interneural connection and that both disorders are spectrum disorders.