• Journal of the Korean Society of Radiology
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• v.13 no.7
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• pp.933-939
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• 2019

The purpose of this study is to provide basic clinical data by evaluating images, measuring absorbed dose and effective dose by using high resolution CT and low dose CT by using anthropomorphic chest phantom and glass dosimeter. Tissue dose was measured by inserting a glass dosimeter into the anthropomorphic chest phantom. A 64-slice CT system (SOMATOM Sensation 64, Siemens AG, Forchheim, Germany) and CARE Dose 4D were used, and the parameters of the high resolution CT were 120 kVp, Eff. Scan parameters of mAs 104, scan time 7.93 s, slice 1.0 mm (Acq. 64 × 0.6 mm), convolution kernel (B60f sharp) were used, and low dose CT was 120 kVp, Eff. mAs 15, scan time 7.41 s, slice 3.0 mm (Acq. 64 × 0.6 mm), scan of convolution kernel B50f medium sharp. CTDIvol was measured at 8.01 mGy for high resolution CT and 1.18 mGy for low dose CT. Low dose CT scans showed 85.49% less absorbed dose than high resolution CT scans.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.247-253
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• 2013

The purpose is a comparative evaluation in the DR System according to the dosimetry and image quality of the quantitative and objective via Direct digital radiography, Indirect digital radiography, Image intensifier (Charge Coupled Device type) digital radiography. The experimental method used rando phantom and measured the entrance surface dose. And through using the measured entrance surface dose and then using the PCXMC program were evaluated risk due to irradiation and the effective dose. SNR and NPS and CNR were measured and analyzed by using 21cm acryl phantom. Significance of measured value was evaluated by statistics method. Entrance surface dose, major organ dose, effective dose all of them were measured the lowest rated in direct DR when it is on the basis of direct DR dose, high-dose ratio were measured in I.I DR approximately 1.3 times, indirect DR approximately 2.4 times. Risk in accordance with radiation also was measured same as dose ratio. On the conclusion that SNR measurement result based on direct DR SNR measurements, low-SNR ratio were measured in I.I DR approximately 7.25 times, indirect DR approximately 1.48 times. On the conclusion that CNR measurement result based on direct DR CNR measurements, high-dose ratio were measured in I.I type DR approximately 1.16 tims and low-dose ratio were measured in indirect DR approximately 0.87 times. Therefore Direct DR system using a-selenium sensing element to detect x-ray photon is thought effectively at the examination such as infant to sensitive irradiation and the genital gland. Because quality image is built by low dose. Also when it is necessary that image test requiring many diagnosis information, indirect DR system is thought effectively.

• The Journal of Korean Society for Radiation Therapy
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• v.28 no.1
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• pp.57-64
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• 2016

Purpose : To evaluate the results of absorbed and effective doses using CBCT and 4D-CBCT settings for lung cancer. Materials and Methods : This experimental study. Measurements were performed using a Anderson rando phantom with OSLD(optically stimulated luminescent dosimeters). It was performed computed tomography(Lightspeed GE, USA) in order to express the major organs of the human body. Measurements were obtained a mean value is repeated three times each. Evaluations of effective dose and absorbed dose were performed the CL-IX-Thorax mode and Truebeam-Thorax mode CBCT. Additionally, compared Truebeam-Thorax mode CBCT with Truebeam-Thorax mode 4D-CBCT(Four-dimensional Cone Beam Computed Tomography) Results : Average absorbed dose in the CBCT of CL-IX was measured in lung 2.505cGy, heart 2.595cGy, liver 2.145cGy, stomach 1.934cGy, skin 2.233cGy, in case of Truebeam, It was measured lung 1.725cGy, heart 2.034cGy, liver 1.616cGy, stomach 1.470cGy, skin 1.445cGy. In case of 4D-CBCT, It was measured lung 3.849cGy, heart 4.578cGy, liver 3.497cGy, stomach 3.179cGy, skin 3.319cGy Average effective dose, considered tissue weighting and radiation weighting, in the CBCT of CL-IX was measured lung 2.164mSv, heart 2.241mSVv, liver 0.136mSv, stomach 1.668mSv, skin 0.009mSv, in case of Turebeam, it was measured lung 1.725mSv, heart 1.757mSv, liver 0.102mSv, stomach 1.270mSv, skin 0.005mSv, In case of 4D-CBCT, It was measured lung 3.326mSv, heart 3.952mSv, liver 0.223mSv, stomach 2.747mSv, skin 0.013mSv Conclusion : As a result, absorbed dose and effective Dose in the CL-IX than Truebeam was higher about 1.3 times and in the 4D-CBCT Truebeam than CBCT of Truebeam was higher about 2.2times However, a large movement of the patient and respiratory gated radiotherapy may be more accurate treatment in 4D-CBCT. Therefore, it will be appropriate to selectively used.

• Korean Journal of Digital Imaging in Medicine
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• v.14 no.2
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• pp.23-31
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• 2012

There are AEC mode and fix mode to exposure when the whole spine antero-posterior radiography is done by using DR equipment. This study compared the utility of fix mode to AEC mode, by evaluating organ dose and effective dose and by examining the quality of radiographic image. GE DEFINIUM 8000 and ART-200X Rando Phantom manufactured by Flukebiometical were used for this study. The Rando phantom was set in front of wall detector of X-rays equipment. AEC mode was set at 80kVp and Fix mode was set at 80kVp, 25mAs, 32mAs, 40mAs, and 50mAs. Whole spine AP image were aquired by combining C, T-L and L-S spine images obtained through 3 exposures. When obtaining C, T-L and L-S spine images, were checked for Air kerma (mGy) value calculated by UNFORS Xi meter attached at the phantom surface of center of radiation field. The effective and organ doses were compared by PCXMC program (PC-Based Monte Carlo Program). The quality of obtained radiographic image was evaluated visually by 3 radiologists using resolution chart. When the effective doses was calculated based on tissue weighting factor of ICRP-103, 1.278mSv was measured by AEC mode, and Fix mode measured 0.405mSv at 25mAs, 0.518mSv at 32mAs, 0.649mSv at 40mAs, and 0.810mSv at 50mAS. In addition, the organ dose measured with esposure at 25mAs by Fix mode was almost equivalent to the organ dose by AEC mode, at the esophagus, thyroid, oral mucosa, salivaly glands located at the cervical spine part, while the organ dose by Fix mode was in general lower than the organ dose by AEC mode at the other organs. When Fix mode at 32mAs, 40mAs, and 50mAs was compared to AEC mode for organ dose in 26 organs, AEC mode had higher measurement in 21 organs but not for than brain, trachea, thyroid, oral mucosa, and salivaly glands which are located at the cervical spine part. The image quality evaluated by resolution test chart was much higher with AEC mode than the quality with Fix mode at all exposure conditions. However, while the image quality of cervical spine exposured at 50mAs by Fix mode was lower than the quality of AEC mode, thoraco-lumbar spine and lumbo-sacral spine were calculated and the quality was similar to AEC mode. Scoliosis occurs mainly at thoraco-lumbar and lumbo-sacral spine, not at cervical spine. Compared to AEC mode, Using the appropriate protocol (80kVp, 50mAs) of fix mode for whole spine AP radiography was thought to be useful because the image quality of the thoraco-lumar and lumbo-sacral spine was similar on AEC mode, Also organ and effective doses can be decreased with Fix mode. Therefore, It is considered that fix mode can be used properly with AEC mode for whole spine AP radiography when considering patient's body posture.

• Journal of Radiation Protection and Research
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• v.26 no.3
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• pp.183-190
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• 2001

The activity concentration of primordial radionuclides i.e., $^{238}U$ series, $^{232}Th$ series and $^{40}K$, in soil samples collected from Udagamandalam environment, have been measured by employing NaI (Tl) Gamma ray Spectrometer. The absorbed gamma dose rate has also been simultaneously measured by using both Environmental Radiation Dosimeter at each soil sampling location (ambient gamma dose) as well as from the gamma dose derived from the activity concentration of the primordial radionuclides. The results of activity concentration of each radio nuclides in soil, absorbed dose rate in air due to soil activity and possible cosmic radiation at each location along with human effective dose equivalent for Udagamandalam environment are presented and discussed.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.696-706
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• 2023

Consequences of an anticipated Beyond Design Basis Accident (BDBA) Long-Term Station Blackout (LTSBO) event with complete loss of grid power in the VVER-1200 reactor of Rooppur Nuclear Power Plant (NPP) of Unit-1 are assessed using the RASCAL 4.3 code. This study estimated the released radionuclides, received public radiological dose, and ground surface concentration considering 3 accident scenarios of International Nuclear and Radiological Event Scale (INES) level 7 and two meteorological conditions. Atmospheric transport, dispersion, and deposition processes of released radionuclides are simulated using a straight-line trajectory Gaussian plume model for short distances and a Gaussian puff model for long distances. Total Effective Dose Equivalent (TEDE) to the public within 40 km and radionuclides contribution for three-dose pathways of inhalation, cloudshine, and groundshine owing to airborne releases are evaluated considering with and without passive safety Emergency Core Cooling System (ECCS) in dry (winter) and wet (monsoon) seasons. Source term and their release rates are varied with the functional duration of passive safety ECCS. In three accident scenarios, the TEDE of 10 mSv and above are confined to 8 km and 2 km for the wet and dry seasons, respectively in the downwind direction. The groundshine dose is the most dominating in the wet season while the inhalation dose is in the dry season. Total received doses and surface concentration in the wet season near the plant are higher than those in the dry season due to the deposition effect of rain on the radioactive substances.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.1949-1958
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• 2023

The International Commission on Radiological Protection (ICRP) Publication 116 was released to provide a comprehensive dataset of the dose coefficients (DCs) for external exposures produced with the adult reference voxel phantoms of ICRP Publication 110. Although an advanced skeletal dosimetry method for photons and neutrons using fluence-to-dose response functions (DRFs) was introduced in ICRP Publication 116, the ICRP-116 skeletal DCs were calculated by using the simple method conventionally used (i.e., doses to red bone marrow and endosteum approximated by doses to spongiosa and/or medullary cavities). In the present study, the photon and neutron DRFs were used to produce skeletal DCs of the ICRP-110 reference phantoms, which were then compared with the ICRP-116 DCs. For photons, there were significant differences by up to ~2.8 times especially at energies <0.3 MeV. For neutrons, the differences were generally small over the entire energy region (mostly <20%). The general impact of the DRF-based skeletal DCs on the effective dose calculations was negligibly small, supporting the validity of the ICRP-116 effective DCs despite their skeletal DCs derived from the simple method. Meanwhile, we believe that the DRF-based skeletal DCs could be beneficial in better estimates of skeletal doses of individuals for risk assessments.

• Journal of Trauma and Injury
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• v.26 no.3
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• pp.198-206
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• 2013

Purpose: This study was performed to calculate and analyze the effective radiation doses from computed tomography (CT) and radiologic intervention in patients in the emergency department (ED) with trauma critical pathway (CP) activation and further to estimate the lifetime attributable risks (LARs) for the incidence of and mortality from cancers induced by the radiation dose. Methods: Through a retrospective electrical chart review of 104 injured patients who trauma critical pathway were activated from November 2012 to March 2013, we calculated effective radiologic doses by taking the product of the dose-linear product of the scan and the conversion coefficient. After a determination of the image results, we divided the patients into two groups, negative or positive, and calculated the effective dose for each group. With these results, we estimated the LARs for the incidence of and the mortality from cancers by using the table in the Biologic Effects of Ionizing Radiation (BEIR)-VII report. Results: A total of 76 patients were enrolled. The mean age was $49.0{\pm}8.5$ years. The mean injury severity score (ISS) was $12.7{\pm}8.4$. The cumulative effective dose (CED) for individual patients varied from 2.8 mSv to 238.8 mSv, and the mean was $47.6{\pm}39.9$ mSv. The CED in patients with an $ISS{\geq}16$($63.2{\pm}26.6$ mSv) was higher than that of patients whose ISS<16($33.5{\pm}23.1$ mSv) (p<0.001). The CED in patients who were treated with surgery or intervention($69.0{\pm}45.2$ mSv) was higher than that of patients who were treated conservatively($33.6{\pm}22.4$ mSv) (p<0.001). The LARs for cancer incidence and mortality were $328.5{\pm}308.6$ and $189.0{\pm}159.3$ per 100,000 people, respectively. Conclusion: The CED and the LAR for trauma CP-activated patients in the ED were significant, so efforts should be made to decrease the effective dose received by severely injured patients.

• Analytical Science and Technology
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• v.20 no.6
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• pp.460-467
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• 2007

Dose rate conversion factor was calculated to estimate the absorbed effective annual doses for soils for the beta-rays and gamma-rays, which were emitted from $^{238,235}U$, $^{232}Th$, and $^{40}K$ isotopes. The most recent data of the emitted energies per decay, half-lifes, and branching ratios, which were obtained from National Nuclear Data Center, were used. When this factor and the effective annual doses for the beta-rays and the gamma-rays of natural radioisotopes were compared with those of Aitken, these of $^{238}U$, $^{232}Th$ and $^{40}K$ are estimated to have good agreements but a large difference is shown in this for $^{235}U$. Through the calculations of effective annual doses by using these factor and the measurements of gamma-ray spectra for soils, which were extracted from prehistoric remains (Mansuri) on Osong, Chungchengbuk-do, The annual effective doses were obtained to be 3.8~5.9 mGy/yr. Also, when these doses including decay elements upper Rn were compared with those on all isotopes, the differences within 9~30 % were obtained. The analysis method of the annual effective doses for the beta-rays and the gamma-rays of the natural isotopes of soils was established by this dose rate conversion factor.

• Imaging Science in Dentistry
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• v.48 no.1
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• pp.21-30
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• 2018

Purpose: To calculate the effective doses of cone-beam computed tomography (CBCT) using personal computer-based Monte Carlo (PCXMC) software (Radiation and Nuclear Safety Authority, Helsinki, Finland) and to compare the calculated effective doses with those measured using thermoluminescent dosimeters (TLDs) and an anthropomorphic phantom. Materials and Methods: An Alphard VEGA CBCT scanner (Asahi Roentgen Ind. Co., Kyoto, Japan) with multiple fields of view (FOVs) was used for this study. The effective doses of the scout and main projections of CBCT using 1 large and 2 medium FOVs with a height >10 cm were calculated using PCXMC and PCXMCRotation software and then were compared with the doses obtained using TLD-100 LiF and an anthropomorphic adult human male phantom. Furthermore, it was described how to determine the reference points on the Y- and Z-axes in PCXMC, the important dose-determining factors in this software. Results: The effective doses at CBCT for 1 large ($20.0cm{\times}17.9cm$) and 2 medium FOVs ($15.4cm{\times}15.4cm$ and $10.2cm{\times}10.2cm$) calculated by the PCXMC software were 181, 300, and $158{\mu}Sv$, respectively. These values were comparable (16%-18% smaller) to those obtained through TLD measurements in each mode. Conclusion: The use of PCXMC software could be an alternative to the TLD measurement method for effective dose estimation in CBCT with large and medium FOVs.