이재성 교수

The objective of this study is to develop a convolutional neural network (CNN) for computed tomography (CT) image super-resolution. The network learns an end-to-end mapping between low (thick-slice thickness) and high (thin-slice thickness) resolution images using the modified U-Net. To verify the proposed method, we train and test the CNN using axially averaged data of existing thin-slice CT images as input and their middle slice as the label. Fifty-two CT studies are used as the CNN training s

Differences in brain activity of children with attention deficit hyperactivity disorder (ADHD) have been compared to normal healthy controls, suggesting neural correlates of cognitive/behavioral symptoms. Symptoms are improved with methylphenidate treatment but limited sources can be cited to show how brain activity in ADHD is altered after pharmacologic treatment. We investigated how long-term oral medication of methylphenidate affects the resting regional cerebral blood flow (rCBF) in ADHD chi

This study suggests that plasticity is present in adult brains of postlingually deaf patients. In the mature brain, auditory deprivation decreased neuronal activity transiently in primary auditory and auditory-related cortices, and, over time, functional reorganization likely takes place in the auditory cortex. Plasticity was prominent in superior temporal and anterior cingulate gyri in the sensory-deprived mature brain and militated against postimplantation improvement in patients with cochlear

Attenuation correction (AC) is essential for the generation of artifact-free and quantitatively accurate positron emission tomography (PET) images. PET AC based on computed tomography (CT) frequently results in artifacts in attenuation-corrected PET images, and these artifacts mainly originate from CT artifacts and PET-CT mismatches. The AC in PET combined with a magnetic resonance imaging (MRI) scanner (PET/MRI) is more complex than PET/CT, given that MR images do not provide direct information

We developed age, gender and ethnic specific brain templates based on MR and Positron-Emission Tomography (PET) images of Korean normal volunteers. Seventy-eight normal right-handed volunteers (M/F=49/29) underwent 3D T1-weighted SPGR MR and F-18-FDG PET scans. For the generation of standard templates, an optimal target brain that has the average global hemispheric shape was selected for each gender. MR images were then spatially normalized by linear transformation to the target brains, and norm

ICA, a rapid and reliable method for extraction of the pure physiologic components, was a valid and useful method for quantification of the regional MBF using H(2)(15)O PET.

We propose a depth-of-interaction (DOI)-encoding method to extract continuous DOI information using a single-layer scintillation crystal array with single-ended readout for cost-effective high-resolution positron emission tomography (PET). DOI information is estimated by different light dispersions along the x- and y-directions tailored by the geometric shape of reflectors around the crystals. The detector module comprised a 22 × 22 array of unpolished LGSO crystals (2.0 × 2.0 × 20 mm(3)). A mul

In recent years, silicon photomultiplier (SiPM) is replacing the photomultiplier tube (PMT) in positron emission tomography (PET) systems due to its superior properties, such as fast single-photon timing response, small gap between adjacent photosensitive pixels in the array, and insensitivity to magnetic fields. One of the technical challenges when developing SiPM-based PET systems or other position-sensitive radiation detectors is the large number of output channels coming from the SiPM array.

(68)Ga labeled NOTA-RGD was a recently developed positron emission tomography (PET) radiotracer for the visualization of angiogenesis, and is regarded as a promising imaging agent for cancer and several other disorders. In this study, we investigated the whole-body distribution and radiation dosimetry of (68)Ga-NOTA-RGD in humans. Ten cancer patients (53.7 ± 13.5 years; 61.5 ± 7.4 kg) participated in this study. PET scans were performed using a PET/computed tomography (scanner in three-dimension

The developed MR-compatible PET insert is designed for insertion into a narrow-bore magnetic resonance imaging scanner, and it provides excellent imaging performance for PET/MR preclinical studies.

For positron emission tomography (PET) inserts to magnetic resonance imaging (MRI) applications, optical fibers have been used for some time to transfer scintillation photons to photomultiplier tubes positioned outside the fringe magnetic field. We previously proposed a novel utilization of an optical fiber for good radio frequency (RF) transmission from body coils to an imaging object. Optical fiber bundles between silicon photomultipliers (SiPM) and scintillation crystals provide an increased

In contemporary tissue engineering there is a need for drug delivery approaches that offer controllable release kinetics from common surgical devices, particularly at healing tissue interfaces. We describe a generally applicable approach to release therapeutic proteins from sutures in a controllable manner. Results demonstrated that several common, commercially available surgical sutures could be coated with nano-porous hydroxyapatite mineral layers using a biomimetic process. The nanoscale morp

In Korean technical documents, many English words are transliterated into Korean in various ways. Most of these words are technical terms and proper nouns that are frequently used as query terms in information retrieval systems. As the communication with foreigners increases, an automatic transliteration system is needed to find the various transliterations for the cross lingual information systems, especially for the proper nouns and technical terms which are not registered in the dictionary. I

Positron emission tomography (PET) detectors with the ability to encode depth-of-interaction (DOI) information allow us to simultaneously improve the spatial resolution and sensitivity of PET scanners. In this study, we propose a DOI PET detector based on a stair-pattern reflector arrangement inserted between pixelated crystals and a single-ended scintillation light readout. The main advantage of the proposed method is its simplicity; DOI information is decoded from a flood map and the data can