• Nuclear Engineering and Technology
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• v.50 no.3
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• pp.519-525
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• 2018

Obtaining knowledge of the absorbed dose up-taken by a certain material when it is exposed to a specific ionizing radiation field is a very important task. Even though there are a plenitude of methods for determining the absorbed dose, each one has its own strong points and also drawbacks. In this article, an innovative idea for the development of a new gamma-ray dosimetry system is proposed. The method described in this article is based on optical colorimetry techniques. A color standard is fixed to the back of a BK-7 glass plate and then placed in a point in space where the absorbed dose needs to be determined. Gamma-ray-induced defects (color centers) in the glass plate start occurring, leading to a degree of saturation of the standard color, which is proportional, on a certain interval, to the absorbed dose. After the exposure, a high-quality digital image of the sample is taken, which is then processed (MATLAB), and its equivalent $I_{RGB}$ intensity value is determined. After a prior corroboration between various well-known absorbed dose values and their corresponding $I_{RGB}$ values, a calibration function is obtained. By using this calibration function, an "unknown" up-taken dose value can be determined.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.4
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• pp.377-385
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• 2002

Ultrasonic tests employing non-ionizing radiation are preferred in nondestructive examinations since they are safe and simple in use. The same principles of the techniques have been taken as valuable tools in medical area for the diagnoses of diseases, in other words, defects of the human body. The paper overviews the principles of the medical diagnosis based on nondestructive ultrasonic tests, and then evaluates experimentally the clinical potential of C scan images not popular in medicine, for detecting the micro fractures of the cortical bone. In the experiment the micro bone fractures were created on the femurs of porks by loading three point bending forces (2-4kN) with the speed of 1 mm/min. As the extent of the fracture was altered, not only X ray images but also ultrasonic C scan images using a focused ultrasonic probe resonated at 25 MHz were obtained. The results showed that ultrasonic C scan images were capable of detecting the micro bone fractures which were not possible to identify by conventional X ray images.

• Journal of Yeungnam Medical Science
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• v.4 no.1
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• pp.1-15
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• 1987

Magnetic Resonance (M.R.) is rapidly emerging technique that provides high quality images and potentially provides much more diagnostic information than do conventional imaging modalities. M.R.I. is conceptually quite different from currently used imaging methods. The complex nature of M.R.I. allows a great deal of flexibility in image product ion and available information, and key points are as follows. 1. M.R.I. offers a non-invasive technique with which to gene rate in vivo human images without ionizing radiation and with no known adverse biological effects. 2. Imaging mechanism of M.R.I. is quite different from conventional imaging modality and for more accurate diagnostic application, It is necessary for physician to understand imaging mechanism of M.R.I. 3. M.R. makes available basic chemical parameters that may provide to be useful for diagnostic medical imaging and more specific pathophysiologic information which are not available by alternate techniques. 4. M.R. can be produced by number of different methods. This flexibility allows the imaging technique to be applicated for particular clinical purpose. Multiplanar and three dimensional imaging may extend the imaging process beyond the single section available with current CT. 5. Future directions include efforts to; a. Further development of hard ware b. More fasternning scan time c. Respiratory and cardiac gated imaging d. Imaging of additional nuclei except hydrogen e. Further development of contrast media f. M.R. in vivo spectroscopy g. Real time M.R. imaging.

• Journal of The Korean Astronomical Society
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• v.47 no.6
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• pp.259-277
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• 2014

G192.8-1.1 has been known as one of the faintest supernova remnants (SNRs) in the Galax until the radio continuum of G192.8-1.1 is proved to be thermal by Gao et al. (2011). Yet, the nature of G192.8-1.1 has not been fully investigated. Here, we report the possible discovery of faint non-thermal radio continuum components with a spectral index ${\alpha}{\sim}0.56(S_{\nu}{\propto}{\nu}^{-{\alpha}})$ around G192.8-1.1, while of the radio continuum emission is thermal. Also, our Arecibo $H_I$ data reveal an $H_I$ shell, expanding with an expansion velocity of $20-60km\;s^{-1}$, that has an excellent morphological correlation with the radio continuum emission. The estimated physical parameters of the $H_I$ shell and the possible association of non-thermal radio continuum emission with it suggest G192.8-1.1 to be an~0.3 Myr-old SNR. However, the presence of thermal radio continuum implies the presence of early-type stars in the same region. One possibility is that a massive star is ionizing the interior of an old SNR. If it is the case, the electron distribution assumed by the centrally-peaked surface brightness of thermal emission implies that G192.8-1.1 is a "thermal-composite" SNR, rather than a typical shell-type SNR, where the central hot gas that used to be bright in X-rays has cooled down. Therefore, we propose that G192.8-1.1 is an old evolved thermal-composite SNR showing recurring emission in the radio continuum due to a nearby massive star. The infrared image supports that the $H_I$ shell of G192.8-1.1 is currently encountering a nearby star forming region that possibly contains an early type star(s).

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.39.3-39.3
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• 2017

To see scientific potential of MIRIS Paschen-${\alpha}$ ($Pa{\alpha}$) Galactic Plane Survey (MIPAPS), we have selected a portion, Galactic longitude from $+96^{\circ}$ to $116^{\circ}$, and inspected $Pa{\alpha}$ detections for 212 sources in WISE H II region catalog. We also list up $35Pa{\alpha}$ large features and $32Pa{\alpha}$ point-like blobs, which have not been cataloged in WISE catalog. For all the sources, we have performed the photometry of $Pa{\alpha}$ emission line, and obtained their $Pa{\alpha}$ intensities and $Pa{\alpha}$ fluxes. For the quantitative comparison, we also make the $H{\alpha}$ mosaic image of the same region by using IPHAS data which have been globally calibrated and released recently. Comparing MIPAPS $Pa{\alpha}$ fluxes with the IPHAS $H{\alpha}$ fluxes enables us to estimate dust extinction and spectral types of ionizing sources. We present the results for some sources.

• Korean Institute of Interior Design Journal
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• v.15 no.4 s.57
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• pp.89-96
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• 2006

Magnetic Resonance Imaging (MRI) scanner is the device to draw an image of conditions and the spread of various tissue in the body. It is used by making the patient into rounded superconductor and using high frequency which cause resonances. It uses superconduction magnet and high frequency that is non-ionizing radiation so can acquire biochemical, physical, and functional information of tissue. It is also very useful because it can scan tomography from many different angles to diagnose disease of a nervous system, the heart, and a skeletal structure. It also has advantages of that there is no risk of radiation exposure and the ability of observation on organizations such as brains, livers and the spinal cord of people. Since these features, the rate of use has been increased accordingly more considerations of the security are required when it plans. The weight of devices and the cover problem of the strong magnetic field which is occurred by magnetic resonance at the time of diagnosis can cause very important structure problems and architectural condition. That also the recent tendency which needs stronger equipment means that planning of the MRI unit should generally aim at purposing of the proximity for the device maintenance and up-grade and of further expansion. However there are not enough studies and data on the magnet resonance imaging in domestic hospitals. According to these reasons, this study has an object of indicating basic data on MRI unit plan standard and alternative proposals.

• The Journal of the Korean dental association
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• v.55 no.11
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• pp.778-788
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• 2017

Ultrasound sonography(US) is used to evaluate various diseases of oral and maxillofacial region including salivary glands, soft tissue and jaw lesions because of easy accessibility and no hazard of ionizing radiation. Also, US can offer dynamic study showing real-time images during diagnostic or surgical procedure. US images provide accurate information about the internal features of lesions on the jaw prior to surgical treatment. Doppler images are used to visualize the vascular distribution of the lesions and to provide additional information to enhance diagnostic value. It is necessary to evaluate the diagnostic value of US and evaluate its usefulness by looking at clinical cases using US images. Therefore, US imaging may be recommended as an assistant image in evaluating jaw lesions. US images provided accurate information about the internal structure of lesions on the jaw prior to surgical treatment, and diagnostic value was enhanced by visualizing the vascular distribution of the lesion using doppler imaging. We report the protocol and suggest the effectiveness of US for various lesions and US-guided sialography.

• The korean journal of orthodontics
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• v.51 no.3
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• pp.189-198
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• 2021

Objective: To estimate the projected cancer risk attributable to diagnostic cone-beam computed tomography (CBCT) performed under different exposure settings for orthodontic purposes in children and adults. Methods: We collected a list of CBCT machines and their specifications from 38 orthodontists. Organ doses were estimated using median and maximum exposure settings of 105 kVp/156.8 mAs and 130 kVp/200 mAs, respectively. The projected cancer risk attributable to CBCT procedures performed 1-3 times within 2 years was calculated for children (aged 5 and 10 years) and adult (aged 20, 30, and 40 years) male and female patients. Results: For maximum exposure settings, the mean lifetime fractional ratio (LFR) was 14.28% for children and 0.91% for adults; this indicated that the risk to children was 16 times the risk to adults. For median exposure settings, the mean LFR was 5.25% and 0.58% for children and adults, respectively. The risk of cancer decreased with increasing age. For both median and maximum exposure settings, females showed a higher risk of cancer than did males in all age groups. Cancer risk increased with an increase in the frequency of CBCT procedures within a given period. Conclusions: The projected dental CBCT-associated cancer risk spans over a wide range depending on the machine parameters and image acquisition settings. Children and female patients are at a higher risk of developing cancer associated with diagnostic CBCT. Therefore, the use of diagnostic CBCT should be justified, and protective measures should be taken to minimize the harmful biological effects of radiation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.564-567
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• 2012

Optical fibers are going to be used for telecommunication, image fibers, sensors under irradiation in nuclear power plants and various irradiation facilities. Especially, Temperature detection sensors using Raman light scattering, temperature or strain sensors using fiber gratings, magnet-optical sensors using photo-magnetic effect, are already commercialized. However, When fibers are exposed to ionizing radiation, color centers are formed in fibers which reduces their light transmission, and it is limited in applying under radiation environments. In this study, $Co^{60}$ gamma-ray induced optical attenuation on Ge-doped single mode(SM) fiber has been measured. Gamma-ray is irradiated for 4hours at the dose rate of 0.5kGy/hr, 2kGy/hr, 8kGy/hr. Consequently, gamma-ray induced loss based on radiation effects in Ge-doped SM fiber occur precisely. Furthermore, dose rate effect that the higher dose rate in the same total dose, the more increase loss of optical fiber and annealing effect that the higher the loss after irradiation, the more increase the recovery rate of the loss are observed in the fiber. This results plan to make use of bases in the study of the radiation-hardened optical fiber.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.103-109
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• 2013

Background: The objective of this study is to determine knowledge about lung cancer among secondary school male teachers in Kudat, Sabah, Malaysia. Materials and Methods: A cross-sectional study was conducted among three secondary schools located in Kudat district, Sabah, Malaysia during the period from June until September 2012. The protocol of this study was approved by ethics committee of Management and Science University, Malaysia. The aims were explained and a consent form was signed by each participant. Respondents were chosen randomly from each school with the help of the headmasters. Self-administrated questionnaires, covering socio-demographic characteristics and general knowledge of lung cancer, were distributed. Once all 150 respondents completed the questionnaire, they passed it to their head master for collecting and recording. All the data were analyzed using Statistical Package for the Social Sciences (SPSS) version 13. ANOVA and t-test were applied for univariate analysis; and multiple linear regression for multivariate analysis. Results: A total of 150 male secondary school teachers participated in this study. Their mean age was $35.6{\pm}6.5$ (SD); maximum 50 and minimum 23 years old. More than half of the participants were Malay and married (52%, 79%; respectively). Regarding the knowledge about lung cancer, 57.3% of the participants mentioned that only males are affected by lung cancer. Some 70.7% mentioned that lung cancer can be transmitted from one person to another. More than half (56.7%) reported that lung cancer is not the leading cause of death in Malaysian males. As for risk factors, the majority reported that family history of lung cancer is not involved. However, 91.3% were aware that cigarettes are the main risk factor of lung cancer and more than half (52%) believed that second-hand smoking is one of the risk factor of lung cancer. More than half (51.3%) were not aware that asbestos, ionizing radiation and other cancer causing substances are risk factors for lung cancer. Quitting smoking, avoiding second-hand smoking and avoiding unnecessary x-ray image of the chest (53.3%, 96.0%, 87.3%; respectively) are the main preventive measures mentioned by the participants. For the factors that influence the participants knowledge, univariate and multivariate analysis showed that only race was significant. Conclusions: Overall, the knowledge of school male teachers about lung cancer was low. However, few items were scored high: cigarettes are the main risk factor; avoiding second-hand smoking; and avoiding x-rays. Interventions to increase lung cancer awareness are needed to improve early detection behavior. Increase the price of pack of cigarettes to RM 20 and banning smoking in public places such as restaurants are highly recommended as primary preventive measures.