• Korean Journal of Digital Imaging in Medicine
• /
• v.5 no.1
• /
• pp.32-44
• /
• 2002

The role of radiology department has been greatly increased in the past few years as the technology in the medical imaging devices improved and the introduction of PACS (Picture Archiving and Communications System) to the conventional film-based diagnostic structure is a truly remarkable factor to the medical history. In addition, the value of using digital information in medical imaging is highly expected to grow as the technology over the computer and the network improves. However, the current medical practice, using PACS is somewhat limited compared to the film-based conventional one due to a poor image quality. The image quality is the most important and inevitable factor in the PACS environment and it is one of the most necessary steps to more wide practice of digital imaging. The existing image quality control tools are limited in controlling images produced from the medical modalities, because they cannot display the real image changing status. Thus, the image quality is distorted and the ability to diagnosis becomes hindered compared to the one of the film-based practice. In addition, the workflow of the radiologist greatly increases; as every doctor has to perform his or her own image quality control every time they view images produced from the medical modalities. To resolve these kinds of problems and enhance current medical practice under the PACS environment, we have developed a program to display a better image quality by using the ROI optical density of the existing gray level values. When the LUT is used properly, small detailed regions, which cannot be seen by using the existing image quality controls are easily displayed and thus, greatly improves digital medical practice. The purpose of this study is to provide an easier medical practice to physicians, by applying the technology of converting the H-D curves of the analog film screen to the digital imaging technology and to preset image quality control values to each exposed body part, modality and group of physicians for a better and easier medical practice. We have asked to 5 well known professional physicians to compare image quality of the same set of exam by using the two different methods: existing image quality control and the LUT technology. As the result, the LUT technology was enormously favored over the existing image quality control method. All the physicians have pointed out the far more superiority of the LUT over the existing image quality control method and highly praised its ability to display small detailed regions, which cannot be displayed by existing image quality control tools. Two physicians expressed the necessity of presetting the LUT values for each exposed body part. Overall, the LUT technology yielded a great interest among the physicians and highly praised for its ability to overcome currently embedded problems of PACS. We strongly believe that the LUT technology can enhance the current medical practice and open a new beginning in the future medical imaging.

• The Journal of the Korea Contents Association
• /
• v.14 no.9
• /
• pp.613-621
• /
• 2014

This study conducted a questionnaire survey with 362 students at department of radiology of college of public health located at G city, who had participated in mentoring program from Mar. 5 to Jun. 21, 2013. Out of 362 questionnaire copies, 315 copies were collected. The students' satisfaction with campus life was significantly affected by whether or not they joined a club, the number of participation into mentoring program per semester, reliability of mentors and mentoring functions. According to the study result, More specifically in terms of the mentoring functions(p<0.001), career development function(p=0.002) and tailored human-resource raising function(p<0.001) gave statistically significant effects on the satisfaction. It is considered that the study results will be used as a fundamental material to research mentoring for college and university students, and will be implemental in using and developing mentoring program as a direct way of preventing the student's dropout. Also it is expected that mentoring program helps college and university students in the transitional period to adulthood experience mentoring before they work at society, therefore playing a positive role for their successful work life as they get employed.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
• /
• v.23 no.2
• /
• pp.57-62
• /
• 2012

Objectives : Characteristic symptoms, including hyperactivity and easy distractibility, in children with attention-deficit hyperactivity disorder (ADHD) suggest that their brain status, even at rest, might differ from that of healthy children. This study was conducted in order to determine whether resting state brain activity is compromised in medication-naive children with ADHD. Methods : Twenty medication-naive children with ADHD (mean age $10.3{\pm}2.5$) and 28 age- and gender-matched healthy volunteers (mean age $10.3{\pm}2.0$) underwent measurements for resting state brain activity using functional magnetic resonance imaging (fMRI). Among resting state related-independent components (RSICs) extracted from fMRI data using independent component analysis, a significant difference in RSICs was observed between groups, using a mixed Gaussian/gamma model. Results : Except for IQ, which was higher in the healthy control group, no demographic difference was observed between the two groups (p<.001). Significantly less activation of one RSIC, which includes the bilateral precuneus/posterior cingulate cortex, occipito-temporal junction, and anterior cingulate cortex, was observed in the ADHD group, compared with the control group (p<.05). Conclusion : An abnormal RSIC, posterior default mode network (DMN), was observed in the medication-naive ADHD group. Results of our study suggest that abnormality of posterior DMN is one of the main pathophysiologies of ADHD.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2016.05a
• /
• pp.271-274
• /
• 2016

CT quality assurance imaging evaluation and enforcement as quantitative assessment by phantom image evaluation, assessment items include There are also contrasting the water attenuation coefficient, uniformity, noise, resolution, spatial resolution, 10mm slice thickness evaluation, contrast resolution, space for the resolution, the slice thickness evaluation, it is possible to estimate the error due to the evaluation by the subjective judgment of the tester, using a subjective error image processing program to be computed to minimize the objective evaluation. Basic recording conditions of the CT image quality control assessment is the same as special medical equipment quality control checks, the images were evaluated quantitatively using IMAGE J. For a CT attenuation coefficient, the uniformity, noise evaluation, were evaluated as CT quality control image the standard deviation of the measured value of the digital processing of image smaller and less noise uniform images than the, contrast and resolution assessment is the size of the diameter of a circle having a large the 1 inch, 0.75 inch, 0.5 inch quality if the diameter of the circle, was evaluated in the small circle in the near circle ellipse. Spatial resolution is evaluated by using a self-extracting features of an image processing program, all of the groups of members comprising the acceptance criteria to automatically extract, was evaluated to be very useful for the quantitative assessment. When CT image quality control assessment on the basis of the results such as the above, if using an image processing program to minimize the subjective judgment of the error evaluator and is determined more efficient than would be made quantitative evaluation.

• Progress in Medical Physics
• /
• v.17 no.1
• /
• pp.40-46
• /
• 2006

Hepatoma is one of 3 most common malignancies in Korea, the survival rate is not improved since last decades because of delayed diagnosis and limited treatment conditions. Radiation was one of treatment options but the impact on the survival is not remarkable. High dose exposure to target area was suggested for improved effect but low tolerance dose of normal liver tissue is the main limited factor. IMRT is the advanced form of 3DCRT, for focusing high dose on target with minimal dose to surrounding normal tissues. Motion of the tumor by respiration, cardiac pulsation and peristalsis is the main treatment harrier of IMRT for treatment of hepatoma patients. Development of QA technique for acceptable geometrical uncertainties and dose error on target volume is essential for IMRT in clinical treatment but proper QA technique is not yet developed. This study compared the verification film dosimetry with measured dose in phantom and calculated dose in planning computer on exactly same conditions of patient treatments. Within 3% dose differences between 3 groups were confirmed. We suggest that our verification QA technique is easy, economic, iterative and acceptable in clinical application for advanced hepatoma patients.

• Investigative Magnetic Resonance Imaging
• /
• v.2 no.1
• /
• pp.73-82
• /
• 1998

Purpose : A precise NMR technique for measuring the rate of water exchange and cell membrane permeability across the hepatocyte membrane using liver-specific MR contrast agent is described. Materials and Methods : The rat hepatocytes isolated by perfusion of the livers were used for the NMR measurements. All experiments were performed on an IBM field cycling relaxometer operating from 0.02MHz to 60 MHz proton Larmor frequency. spin-echo pulse sequence was empolyed to measure spin-lattice relaxation time, T1. The continuous distribution analysis of water proton T1 data from rat hepatocytes containing low concentrations of the liver specific contrast agent, Gd-EOB-DTPA, modeled by a general two compartment exchange model. Results : The mean residence time of water molecule inside the hepatocyte was approximately 250 msec. The lower limit for the permeability of the hepatocyte membrane was $(1.3{\pm}0.1){\;}{\times}{\;}10^{-3}cm/sec$. The CONTIN analysis, which seeks the natural distribution of relaxation times, reveals direct evidence of the effect of diffusive exchange. the diffusive water exchange is not small in the intracellular space in the case of hepatocytes. Conclusions : Gd-EOB-DTPA, when combined with continuous distribution analysis, provides a robust method to study water exchange and membrane permeability in hepatocytes. Water exchange in hepatocyte is much slower thatn that in red blood cells. Therefore, tissue-specific contrast agent may be used as a functional agent to give physiological information such as cell membrane permeability.

• Investigative Magnetic Resonance Imaging
• /
• v.13 no.1
• /
• pp.22-30
• /
• 2009

Purpose : Patient motion during magnetic resonance (MR) imaging is one of the major problems due to its long scan time. Entropy based post-processing motion correction techniques have been shown to correct motion artifact effectively. One of main limitations of these techniques however is its long processing time. In this study, we propose several methods to reduce this long processing time effectively. Materials and Methods : To reduce the long processing time, we used the separability property of two dimensional Fourier transform (2-D FT). Also, a computationally light metric (sum of all image pixel intensity) was used instead of the entropy criterion. Finally, partial Fourier reconstruction, in particular the projection onto convex set (POCS) method, was combined thereby reducing the size of the data which should be processed and corrected. Results : Time savings of each proposed method are presented with different data size of brain images. In vivo data were processed using the proposed method and showed similar image quality. The total processing time was reduced to 15% in two dimensional images and 30% in the three dimensional images. Conclusion : The proposed methods can be useful in reducing image motion artifacts when only post-processing motion correction algorithms are available. The proposed methods can also be combined with parallel imaging technique to further reduce the processing times.

• Journal of radiological science and technology
• /
• v.32 no.4
• /
• pp.427-435
• /
• 2009

We surveyed 586 patients who had been examined CCTA. Out of those patients, 299 (52%) has stenosis of coronary arteries; 166 males (28%) and 133 females (23%). Among them 246 stenosis patients (82.6%) are in 50's to 70's. The number of patients with 50% or more stenosis in more than 1 coronary artery is 299 including 43 males (33.9%) in their 60's and 39 females (37.5%) in their 70's. When a vessel score is higher than 2 points, 70 patients (50.1%) among 139 have 70% or more stenosis; 32 males (39.5%) in their 60's and 27 females (46.6%) in their 70's. It is noted that 14 patients in their 70's show more cases compared to other ages up to 2 or even 5 times when a vessel score is 3 points. LAD shows 77.6% of stenosis, LCX 47.5% and RCA 60.5%. Frequency of a triple vessel disease is high for patients in their 70's; 15 males (36.6%) and 13 females (56.5%) for both. 196 people (33.4%) in the group with stenosis have calcification, while only 40 (6.8%) in the group without stenosis have it. It means that calcification has a significant, if not absolute, correlation with stenosis of coronary arteries.

• The Journal of the Korean bone and joint tumor society
• /
• v.12 no.2
• /
• pp.118-125
• /
• 2006

Purpose: We report elastofibroma which is a rare fibrous lesion that most commonly occurs in the between subscapularis and thoracic cage. Materials and Methods: Four patients include one man and three women, the average age was 70 years and the average follow up period was six months. Two patients had on left side, two patients had on both sides. Main symptom was palpable mass. One patient complained mild pain, two complained scapular snapping. Results: All four masses removed with marginal or wide margin. Average mass size was 9.7${\times}$7.2${\times}$3.8 cm. Preoperative symptoms disappeared after surgery. All of the patients have returned to their daily living and showed no recurrence. There was no serious complication such as limitation of shoulder motion and winged scapula. Conclusion: Elastofibroma scapulae can be diagnosed through patient's age, tumor location and radiological finding without preoperative biopsy. When patient is symptomless, observation is enough without surgical operation. Surgical operation considered for relieve of symptoms of pain and snapping.

• Journal of radiological science and technology
• /
• v.36 no.1
• /
• pp.11-17
• /
• 2013

Currently, there are many studies being conducted around the world to reduce exposure dose to radiation for patients to receive medical treatments in a safe environment. We developed and fabricated of this shield that the patients are protected from the radiation and are need of safety control during breast imaging. In this study, for breast imaging, GE Senography 2000D were used and set at SID 65cm, 28kVp, and 63mAs. The measuring instrument was Fluke's Victoreen 6000-529. And we performed Face Block on with 30 patients. The chamber on the actual thyroid glands to take CC and MLO and measure the dosage before and after wearing the Face Block. For the results, after wearing the Face Block, exposure was decreased by 53.8%-100% and 65.8% in average in CC View and by 50%-100% and 60.7% in average in MLO View. The development of the Face Block that practically decreased the exposure dose of thyroid glands, crystalline eyes during breast imaging and reduced the patients' anxiety during breast imaging. The Face Block is expected to improve patients' satisfaction and contribute to reducing patients' exposure dose, but more efforts should be made to reduce exposure dose to medical radiation.