• Journal of radiological science and technology
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• v.37 no.4
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• pp.239-246
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• 2014

Filter absorbs low-energy X-ray to increase the average energy and reduces patient exposure dose. This study investigates if the materials of Mo and W could be used for the digital imaging device CR by conducting image assessment and dose measurement of SNR, FOM and histogram. In addition, measurement of beam quality was conducted depending on the material of the filter, and at the same time, a proper combination of filters was examined depending on the change in tube voltage (kVp). In regard to entrance skin dose, Mo filter showed the dose reduction by 42~56%, compared to Cu filter. Moreover, Mo filter showed higher transmission dose by around 1.5 times than that of Cu filter. In image assessment, it was found that W was unsuitable to be used as a filter, whereas Mo could be used as a filter to reduce dose without decline in image quality at the tube voltage of 80 kVp or higher. As tube voltage increased, 2.0 mm Al+0.1 mm Mo almost had a similar histogram width to that of 2.0 mm Al+0.2 mm Cu. Therefore, Mo filter can be used at relatively high tube voltage of 80 kVp, 100 kVp and 120 kVp. The SNR of 2.0 mm Al+0.1 mm Mo did not show any significant difference from those of 2.0 mm Al+0.2 mm Cu and 2.0 mm Al+0.1 mm Cu. As a result, if Mo filter is used to replace Cu filter in general radiography, where 80 kVp or higher is used for digital radiation image, patient exposure dose can be reduced significantly without decline in image quality, compared to Cu filter. Therefore, it is believed that Mo filter can be applied to chest X-ray and high tube voltage X-ray in actual clinical practice.

• Journal of Korea Multimedia Society
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• v.1 no.1
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• pp.45-55
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• 1998

In the tele-medical system, the broadband network for multimedia telecommunication and the multimedia terminal equipment for the remote access of the tele-medical information are essential. Especially, the tele-medical terminal equipment should provide the multimedia GUI environment in order to support the similar medical process by the tele-medical system. In this paper, we present a multimedia GUI (Graphic User Interface) for a Multimedia Tele-Medical System (TeleMedi_GUI) based on ATM/B-ISDN. In the tele-medical system, one workstation is used for the multimedia data server that is supporting multiple client terminals that are connected by the ATM network. The client terminals are based on Multimedia Personal Computers, and provide the remote access environment of the tele-medical database. We also developed the remote access protocols among the clients and the server to access multimedia medical information of the multimedia server. With using the TeleMedi_GUI, the doctors can examine and treat patients efficiently, using image data like X-ray/CT and voice data such as the S-ray diagnosis. The result of this paper can be applied to the following areas: 1) the implementation of the advanced medical service system interconnecting the small-scale health center and general hospitals, 2) the development of a fully computerized medical information system within the hospital.

• Archives of design research
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• v.17 no.4
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• pp.51-60
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• 2004

The medical instrument industry which is one of the high value added industry has been neglected on the various system and political support because it has been recognized as an unknown field to the public although it is the very easy-approaching field for the export market that minimize a technological gap between advanced country and Korea. Especially, the product design that is very important element for the efficient medical treatment and the psychological stabilization of patient is a typical field of lack of investment and support by the unconcern and lack of understanding of design. Therefore this research suggests the current problem of design with the general inquiry of internal and external market situation and domestic medical instrument industry and also it has the conclusion of an alternative proposal for the solution with the design development processing of a moving type-image diagnostic equipment. We will emboss the importance of design competitiveness, suggest the model and basic data to the medical instrument company that starts later, and be a role of inspiration for the lasting investible desire with this research.

• Journal of dental hygiene science
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• v.12 no.1
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• pp.23-29
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• 2012

The purpose of this study was to investigate the image and the awareness of dental hygienists in dental hygiene and non-dental hygiene students. The subjects in this study were 414 students who were in the three-year-course department of dental hygiene and in another four-year-course non-dental hygiene department in G college in the city of Gwangju. After a survey was conducted, the collected data were analyzed. The findings of the study were as follows: 1. As a result of general awareness about dental hygienists, the dental hygiene students knew 97.5% and non-dental hygiene students knew 80.6% about dental hygientist as a job. There were significant differences(p<0.001). In regard of awareness about status in medical law, medical technician was the highest in the dental hygiene students(52.8%), and medical assistant was the highest in the non-dental hygiene students(48.8%) 2. As a result of awareness about the main tasks of dental hygienists X-ray and scaling were the highest in the dental hygiene students(42.3%), and treatment assistance was the highest in the non-dental hygiene students(32.9%). 3. In regard to awareness about image of dental hygienists, both groups were the highest in professionalism and were the lowest in negative image. All variable were differences statistically between dental hygiene and non-dental hygiene students(p<0.05).

• Progress in Medical Physics
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• v.23 no.3
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• pp.154-161
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• 2012

Digital Radiography (DR) has rapidly developed in megavoltage X-ray imaging (MVI). Thus, a very simple and general quality assurance (QA) method is required. The purpose of this study was to evaluate the modulation transfer function (MTF), the noise power spectrum (NPS) and the detective quantum efficiency (DQE) for MVI using general QA method and computed radiography (CR) device. We used tungsten edge block with $19{\times}10{\times}1cm^3$ thickness and 6MV energy. For detector, CR-IP (image plate), CR-IP-lead, the CR-IP-back (lanex TM fast back screen), CR-IP-front (lanex TM fast front screen) were used and pre-sampling MTF was calculated. The MTF of CR-IP-front showed the highest value with 1.10 lp/mm although the CR-IP showed the only 0.70 lp/mm. The best NPS was observed in CR-IP front screen. According to the increase in spatial frequency, our results showed that DQE was approximately 1.0 cycles/mm. The present study demonstrates that the QA method with our home-made edge block can be used to evaluate MTF, NPS and DQE for MVI.

• Journal of Korea Multimedia Society
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• v.21 no.2
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• pp.98-107
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• 2018

In this paper, we propose a method to classify the skeletal maturity with a small amount of hand wrist X-ray image using deep learning-based meta-learning. General deep-learning techniques require large amounts of data, but in many cases, these data sets are not available for practical application. Lack of learning data is usually solved through transfer learning using pre-trained models with large data sets. However, transfer learning performance may be degraded due to over fitting for unknown new task with small data, which results in poor generalization capability. In addition, medical images require high cost resources such as a professional manpower and mcuh time to obtain labeled data. Therefore, in this paper, we use meta-learning that can classify using only a small amount of new data by pre-trained models trained with various learning tasks. First, we train the meta-model by using a separate data set composed of various learning tasks. The network learns to classify the bone maturity using the bone maturity data composed of the radiographs of the wrist. Then, we compare the results of the classification using the conventional learning algorithm with the results of the meta learning by the same number of learning data sets.

• Journal of radiological science and technology
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• v.22 no.1
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• pp.43-47
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• 1999

In order to obtain effective utilization of intensifying screens[$CaWO_4(W),\;Gd_2O_2S:Tb(Gd)$, BaFCl : Eu(Ba)] over the diagnostic radiology range, we calculated absorption coefficient (${\mu}$), absorption efficiency (${\eta}_{\alpha}$) and absorbed energy ratio(R) and analyzed effects of these properties on X-ray image, finally concluded as below. Regardless of presence of contrast media, absorption coefficient of Gd the highest and decreased with increase of thickness and kVp. Absorption efficiency related with absorbance of fluorescent materials showed the highest value for the Gd, and discontinuous points exhibited at around $80{\sim}90\;kVp$ and $90{\sim}100kVp$ for the Ba and the Gd, respectively. Furthermore, the absorbed energy ratio(R) correspond to contrast of reflection showed the largest value for the W in the absence of contrast media, and for the Gd in the case of the existence of it, and the ratio was decreased with increasing of incident energy. Owing to these properties, we assumed that it was more preferable to use rare earth type intensifying screen for the radiography using in the C.M.(I, Ba), while in the general radiography, $CaWO_4$ intensifying screen was applicable.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.6
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• pp.34-44
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• 1996

In order to examine the accuracy of the intensity method, the fiber orientation-angle distribution of fiber-reinforced polymeric composites is measured using image processing. The fiber orientation function is calculated from the fiber orientation measured by the soft X-ray photograph. Theoretical and experimental results of fiber orientation function are compared for the composites with different fiber contents and fiber orientations. The intensity method is used for the experimental investigation and the measured fiber orientation function is compared to the calculated one. The relations between the measured and the simulated fiber orientation functions $J{\small{M}}$ and $J{\small{S}}$ respectively are identified. For the fiber length of 1.000mm and 2.000mm, it shows that $J{\small{M}}=0.83J{\small{M}}$. However. in general. the value of $J{\small{M}}$ decreases as the fiber length increases. For GFRP composites the relations between $J{\small{M}}$ and theoretical value J show that $J{\small{M}}$=0.73J for short fiber and $J{\small{M}}$=0.81J for long fiber.

• Journal of radiological science and technology
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• v.34 no.4
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• pp.277-285
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• 2011

To determine the quality control of UGIS, we acquired 105 patients sampling image at 21 general screening centers. The results of image quality evaluation table containing two countries's UGIS showed that the mean of image qualified education table of our country was 73.3 and the standard error was 4.49; In addition, 19 organizations of 21 general screening centers were given appropriate judgement. The average of image qualified education table of Japan was 58 and the standard error was 4.45. Only 8 organizations were given appropriate judgement. Although we made the image quality evaluation tables with same images, there were many differences in the result of two tables. We figured out the problem about the description of whole stomach and photograph skills. Furthermore, we analysed the situation of the UGIS at each general screening center with the acquired images. The biggest problem of the UGIS of our country was that the procedures were performed without clear medical methods. Methods of UGIS were different at every 21 general screening centers, and most of them did not take exam of anterior surface of stomach of the UGIS. In addition, some general screening centers did not include mucosal relief method or esophagography which is required to include in the image qualified education table of our country. Because polisography is used in the same body position, the problem occured about indiscreet exposure dose of patients. Therefore we have to make an effort to get X-ray images which have enough diagnosis information by the quality control of UGIS.

• Journal of the Korean Wood Science and Technology
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• v.37 no.1
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• pp.37-47
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• 2009

For the inspection of wood, machine vision is the most common automated inspection method used at present. It is required to sort wood products by grade and to locate surface defects prior to cut-up. Many different sensing methods have been applied to inspection of wood including optical, ultrasonic, X-ray sensing in the wood industry. Nowadays the scanning system mainly employs CCD line-scan camera to meet the needs of accurate detection of lumber defects and real-time image processing. But this system needs exact feeding system and low deviation of lumber thickness. In this study low cost CCD area sensor was used for the development of image processing system for lumber being fed. When domestic red pine being fed on the conveyer belt, lumber images of irregular term of captured area were acquired because belt conveyor slipped between belt and roller. To overcome incorrect image merging by the unstable feeding speed of belt conveyor, it was applied template matching algorithm which was a measure of the similarity between the pattern of current image and the next one. Feeding the lumber over 13.8 m/min, general area sensor generates unreadable image pattern by the motion blur. The red channel of RGB filter showed a good performance for removing background of the green conveyor belt from merged image. Threshold value reduction method that was a image-based thresholding algorithm performed well for knot detection.