Jung-Whan Min

Dose-dependent influence of short-term intermittent ethanol intoxication on cerebral neurochemical changes in rats detected by ex vivo proton nuclear magnetic resonance spectroscopy.

The aim of this study was to quantitatively assess the effects of short-term intermittent ethanol intoxication on cerebral metabolite changes among sham controls (CNTL), low-dose ethanol (LDE)-exposed, and high-dose ethanol (HDE)-exposed rats, which were determined with ex vivo high-resolution spectra. Eight-week-old male Wistar rats were divided into three groups. Twenty rats in the LDE (n=10) and the HDE (n=10) groups received ethanol doses of 1.5 and 2.5 g/kg, respectively, through oral gavage every 8h for 4days. At the end of the 4-day intermittent ethanol exposure, one-dimensional ex vivo 500-MHz ¹H nuclear magnetic resonance spectra were acquired from 30 samples of the frontal cortex region (from the three groups). Normalized total N-acetylaspartate (tNAA: NAA+NAAG [N-acetylaspartyl-glutamate]), GABA, and glutathione (GSH) levels were significantly lower in the frontal cortex of the HDE-exposed rats than that of the LDE-exposed rats. Moreover, compared to the CNTL group, the LDE rats exhibited significantly higher normalized GABA levels. The six pairs of normalized metabolite levels were positively (+) or negatively (-) correlated in the rat frontal cortex as follows: tNAA and GABA (+), tNAA and aspartate (Asp) (+), myo-Inositol (mIns) and Asp (-), mIns and alanine (+), mIns and taurine (+), and mIns and tNAA (-). Our results suggested that short-term intermittent ethanol intoxication might result in neuronal degeneration and dysfunction, changes in the rate of GABA synthesis, and oxidative stress in the rat frontal cortex. Our ex vivo(1)H high-resolution magic angle spinning nuclear magnetic resonance spectroscopy results suggested some novel metabolic markers for the dose-dependent influence of short-term intermittent ethanol intoxication in the frontal cortex.

Usefulness of contrast agent involving high gadolium content for myocardial viability assessment

The purpose of this study is to increase contrast to noise ratio(CNR) in myocardial viability test by using contrast agent which highly content gadolinium(1mmol/mL) maximizing diagnostic value. This research method that four hundred four patients were underwent the MRI scanning two hundred eighty four of them were injected commercial contrast media which have 0.5mmol/L and the rest of them were injected new contrast media(gadobutrol) which have 1mmol/mL of molarity to study the contrast difference depending on the molarity of the contrast agent signal intensities of normal ventricle and left ventricle were measured to compare and evaluate signal to noise ratio(SNR) and CNR of the images. As result, 1mmol/mL contrast agent showed higher SNR by 25.13% in myocardium and 30.74% in left ventricle. CNR was proved to be better in 1mmol/mL contrast agent by 31.29%. The results above were all statistically meaningful. Therefore, contrast agent contenting more gadolinium which was 1mmol/mL in this study, could more effectively shorten T1 relaxation time, increase the signal intensity and at the same time maximize CNR and diagnostic value. This study firstly report the usefulness of 1mmol/mL contrast agent in patients allegedly suffering cardiac diseases and it is considered to increase diagnostic value.

Neutron dosimetry depending on the number of portals for prostate cancer IMRT(Intensity-Modulated Radiation Therapy)

Abstract The aim of this study was provide basic information and establish the criteria in radiation therapy planningby measuring the absorbed neutron dose of normal tissues and lesions according to the number of portals. From September 2013 to January 2014, 20 patients who were diagnosed with prostate cancer and were previously treated with radiation therapy were replanned retrospectively to measure the absorbed neutron dose distribution according to the number of portals. The absorbed neutron dose was measured in each of the 5, 7 and 9 portals using a 15 MV energy, which meant a therapeutic dose of 220 cGy. The optical stimulation luminescence dosimeter was separated by 20cm and 60cm away from the center of the field of view. As a result, the average radiation dose in the abdomenappeared to have a positive relationship with the number of portals, which was statistically significant (p<.05). The average radiation dose was 4.34±1.08. The average radiation dose in the thyroid was 2.71±.37. Although it showeda positive relationship with the number of portals, it did not have statistical significance. The number of portals andthe neutron dose depending on the position showed a significant positive relationship, particularly in the abdomen. As a result of linear regression analysis, as the number of the portal increased in steps, the average volume of the neutrons increased significantly (0.416 times). In conclusion, efficient selection of the number of portals is needed considering the difference in the absorbed neutron dose in the normal tissues depending on the number of the portals.

A Study on the Feasibility of a National Practical Examination in the Radiologic Technologist

Currently practical examination can`t function as a practical technique ability evaluation`, so there is a contradiction which even though a radiologist passed an examination for license, he has to complete a training course. To improve this problem, this study tried to deduce the most reasonable plan from the analysis of propriety of currently practical examination and what improvement points are. This conduct study was compared and analyzed the performance or practical examination of radiology from leading advanced countries within the samples of 634 radiologists, 56 professors of radiology. From the result of this study, it showed that radiology practical examination was difficult to be substituted by radiology clinical training since there were some critical differences between conditions of domestic and advanced countries. Therefore, the introduction of the radiology practical examination is inevitable and necessary. However the currently practical examination can`t evaluate actual practical ability, so we could conclude that converting it into OSCE (objective structured clinical examination) form is essential. From now on, we should consider more about an in-depth study on types of advanced practical examination and how to suggest and present them in order to become an one of the advanced countries for radiologic technologist.

Analysis of radiation exposure in radiation worker in medical facility and student in clinical practice

This study was conducted to determine the appropriateness of systemic radiation exposure control for students in clinical practice by comparing radiation exposure in radiography employees at different stations of a hospital with that of students conducting clinical practice using identical stations. Overall, 121 students who conducted clinical practice in the department of radiology area of C university hospital from July 2014 to August 2014 and 62 workers working in the same medical facility (47 in the department of radiology, 8 in the department of radiation oncology, 7 in the department of nuclear medicine) were investigated. The radiation exposure experienced by students was measured for 8 weeks, which is the duration of the clinical practice. Additionally, radiation exposure of workers were classified into 4 groups, department of radiology, department of radiation oncology, and department of nuclear medicine was compared. Dose was measured with OSLD and differences among groups were identified by ANOVA followed by Duncans multiple range test. Among employees, those in the department of radiology, oncology and nuclear medicine were exposed depth doses of 0.127±0.331 mSv, 0.01±0.003 mSv, and 0.431±0.205 mSv, respectively, while students were exposed to 0.143±0.136 mSv. Additionally, workers in the department of radiology, oncology and nuclear medicine were exposed to surface doses of 0.131±0.331 mSv, 0.009±0.003 mSv, and 0.445±0.198 mSv, respectively, while students were exposed to 0.151±0.14 mSv, which was significantly different in both doses (p < 0.01). The average dose that students received is higher than that of the other groups (except for nuclear medicine workers), indicating that further improvements must be made in systemic controls for individual radiation exposure by including the students as subjects of management for protection from radiation.

The increase of blood vessels using a signal during the image acquisition phase T1 shortening effect

The purpose of this study is to obtain a useful diagnostic image by increasing the signal strength of the peripheral artery, was to use a T1 shortening effect of gadolinium contrast agents to improve the disadvantages of the phase image. From october to december 2014 thirty patients were underwent the MRI scanning, except for heart disease. Research method was evaluated comparing the image after gadolinium contrast MR image acquisition step before evaluating the difference between the signal intensity for T1 shortening effect. In frontal lobe 19.45%, temporal lobe 23.09%, occipital lobe 25.45%, parietal lobe 18.82%, cerebellum 20.93% after peripheral arterial signal strength results of gadolinium contrast agent injection was increased significantly after injection of gadolinium both statistically significant. After injecting a contrast agent gadolinium in SWI by increasing the signal strength of the T1 shortening effect can be obtained when using the phase image to give a useful image in diagnosis and treatment.

Reduced dose uncertainty in MRI-based polymer gel dosimetry using parallel RF transmission with multiple RF sources

In this work, we present the feasibility of using a parallel RF transmit with multiple RF sources imaging method (MultiTransmit imaging) in polymer gel dosimetry. Image quality and B1 field homogeneity was statistically better in the MultiTransmit imaging method than in conventional single source RF transmission imaging method. In particular, the standard uncertainty of R2 was lower on the MultiTransmit images than on the conventional images. Furthermore, the MultiTransmit measurement showed improved dose resolution. Improved image quality and B1 homogeneity results in reduced dose uncertainty, thereby suggesting the feasibility of MultiTransmit MR imaging in gel dosimetry.

The usefulness of the contrast agent high in gadolinium for the contrast-enhanced magnetic resonance hip arthrography

The purpose of this study is to maximize diagnositc usefulness with increasing signal to noise ratio(SNR) and contrast to noise ratio(CNR) by using a 1mmol/mL gadolinium contrast agent. From January 2012 to June 2013 fourty-seven patients were underwent the MRI scanning to investigate the contrast difference in gadolinium content. Twenty of the patients were injencted the commercial contrast agent containing 0.5mmol/mL gadolinium and the rest of them were injected the new contrast agent containing 1mmol/mL gadolinium called gadobutrol. We measured and evaluated each SNR and CNR of the hip joint space, iliopsoas muscle and femoral head. As a result, using the 1mmol/mL gadolinium contrast agent had the higher SNR results than using the 0.5mmol/mL agent(27% in the hip joint, 30.01% in the femoral head). Also CNR using the 1mmol/mL gadolinium agent was proved to be higher than that of using 0.5mmol/mL agent(28.31% in the ilopsoas muscle and 26.74% in the femoral head). Therefore, the contrast agent containing more gadolinium like 1mmol/mL used in this study is more effective to shorten T1 relaxation time, so it increases the signal intensity and CNR and furthermore maximizes diagnostic value. This study reports the usefulness of the 1mmol/mL contrast agent in the contrast-enhanced magnetic resonance hip arthrography for the first. Therefore, it can be considered to have an meaningful academic value as showing the method for increasing the diagnostic usefulness by using the 1mmol/mL contrast agent.

Evaluation of quantitative on T-spine exhalation technique and T-spine breathing technique of natural breathing

Abstract Measurements of CNR(Contrast to Noise Ratio) and SNR(Signal to Noise Ratio) of T-spine breathing technique (TBT) using spontaneous breathing and T-spine exhalation technique (TET) with full exhalation were carried out, and with which the more appropriate method was suggested. Both TBT and TET were examined in a sample of fifty-three patients who visit to our hospital for spinal disease from June 2012 to November 2012. All images were evaluated with CNR measured from the differences between the mean pixels and contrast density as setting ROI of spinous process, pedicle, vertebral body, intervertebral foramen, and intervertebral disk using Image J. SNR was measured with the mean pixels and the standard deviation as setting ROI of vertebral body using Image J. In CNR comparison and SNR comparison of TET and TBT, TBT was indicated as excellent in ROI of pedicle, vertebral body, intervertebral foramen and intervertebral disk, and statistical analysis were significant(p<.01). As TBT indicated excellent images compared to the existing T-spine lateral radiography, T-spine lateral radiography would be reestablished and significant as applying to various medical institutions.

A study of contrast agent peak time using biomechanics factors experimental contrast medium infusion test using at contrast enhanced magnetic resonance angiography

Abstract In this study was explored minimize side effects due to the additional injection of contrast medium and maintaining a high resolution imaging applied to the inspection and analysis of the contrast medium that affect the peak time biomechanics factors. Included 48 patients using the test bolus method, after measuring a patients biomechanics factors of inspection before and during the test, correlation between contrast medium peak time and learn, matches the regression equation calculated and measured contrast medium peak time was assessed by the Bland Altman plot. Research result, inspections of SBP, HR contrast medium peak time and a significant negative correlation was, step 1, every increase, the contrast medium peak time significantly to -0.018 and -0.159 decreased, a fairly high concordance no difference between the two method. In conclusion, the regression equation using the existing methods, while maintaining excellent image quality that contrast medium is reduced to a patient, it can conclude that the alternative to the existing methods.