• Journal of Radiation Protection and Research
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• 제31권1호
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• pp.1-7
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• 2006

The measured mean activities of $^{226}Ra,\;^{232}Th,\;^{40}K\;and\;^{137}Cs$ in the soil of Bahawalpur, Bahawalnagar and Rahimyar Khan Bistricts were 32.9, 53.6, 647.4 and 1.8 Bq $kg^{-1}$. The average absorbed dose rate calculated from these activities was 74.3 nGy $h^{-1}$ and the mean annual effective dose rate was found to be 0.46 mSv $y^{-1}$. Absorbed doses to different body organs were derived from annual effective doses using tissue weighting factors. Radiation induced fatal cancer risks were assessed by using ICRP 60 Model. Estimations incurred 184deaths per year due to cancer.

• Korean Journal of Radiology
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• 제22권8호
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• pp.1341-1351
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• 2021

Objective: To compare the quality of various polychromatic and monochromatic images with or without using an iterative metal artifact reduction algorithm (iMAR) obtained from a dual-energy computed tomography (CT) to evaluate total knee arthroplasty. Materials and Methods: We included 58 patients (28 male and 30 female; mean age [range], 71.4 [61-83] years) who underwent 74 knee examinations after total knee arthroplasty using dual-energy CT. CT image sets consisted of polychromatic image sets that linearly blended 80 kVp and tin-filtered 140 kVp using weighting factors of 0.4, 0, and -0.3, and monochromatic images at 130, 150, 170, and 190 keV. These image sets were obtained with and without applying iMAR, creating a total of 14 image sets. Two readers qualitatively ranked the image quality (1 [lowest quality] through 14 [highest quality]). Volumes of high- and low-density artifacts and contrast-to-noise ratios (CNRs) between the bone and fat tissue were quantitatively measured in a subset of 25 knees unaffected by metal artifacts. Results: iMAR-applied, polychromatic images using weighting factors of -0.3 and 0.0 (P_-0.3i and P_0.0i, respectively) showed the highest image-quality rank scores (median of 14 for both by one reader and 13 and 14, respectively, by the other reader; p < 0.001). All iMAR-applied image series showed higher rank scores than the iMAR-unapplied ones. The smallest volumes of low-density artifacts were found in P_-0.3i, P_0.0i, and iMAR-applied monochromatic images at 130 keV. The smallest volumes of high-density artifacts were noted in P_-0.3i. The CNRs were best in polychromatic images using a weighting factor of 0.4 with or without iMAR application, followed by polychromatic images using a weighting factor of 0.0 with or without iMAR application. Conclusion: Polychromatic images combined with iMAR application, P_-0.3i and P_0.0i, provided better image qualities and substantial metal artifact reduction compared with other image sets.

• 한국자기공명학회논문지
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• 제9권1호
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• pp.29-37
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• 2005

Intra-cellular drug uptake in Xenopus laevis oocyte has been elucidated using localized MR spectroscopy (MRS) and PFG NMR techniques at a 600 $MH_z$(Bruker, 14.1 T) NMR spectrometer. The localized MRS has been done with a homemade probe, and shows the intra-cellular uptake of nicotinamide. The self-diffusion of the molecule in Xenopus oocyte was obtained by PFG NMR technique. The measured data are well fitted with a linear combination of two exponential functions, which shows that there are two types of drug molecules, intra-and extra-cellular molecules. Diffusion coefficients of intra- and extra-cellular drug molecules are 3.7 $\times$ $10^{-11}$ $\m^{2}/s$and 6.4 $\times$ $10^{-10}$ $\m^{2}/s$, respectively. In the weighting factors there is shown that about 5% of drug molecule is inside the cells. These techniques can be used for drug screening in molecule-, cell-, and tissue-based preclinical test.

• 대한치과의사협회지
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• 제53권8호
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• pp.558-568
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• 2015

Objective: The objectives of this study were to measure pediatric organ and effective doses of cone-beam computed tomography (CBCT) for orthodontic analysis and to compare them to those of panoramic and lateral cephalometric radiography, the conventional radiography for orthodontic analysis. Materials and Methods: Alphard VEGA for CBCT, Planmeca Proline XC for panoramic radiography and Orthophos CD for cephalometric radiography were used for this study. Thermoluminescent dosimeter (TLD) chips were located at 24 anatomic sites of 10-year-old anthropomorphic phantom and exposed during CBCT (C-mode; $200{\times}179mm$ FOV), panoramic and lateral cephalometric radiographic procedures at the clinical exposure settings for 10-year-old patient. Pediatric organ and effective doses were measured and calculated using ICRP 2007 tissue weighting factors. Results: Effective doses of CBCT, panoramic radiography and lateral cephlometric radiography in pediatric clinical exposure settings were $292.5{\mu}Sv$, $19.3{\mu}Sv$, and $4.4{\mu}Sv$ respectively. The thyroid gland contributed most significantly to the effective dose in all the radiographic procedures. Conclusion: Effective dose of CBCT was about 12 times to conventional radiographic procedures for orthodontic analysis in pediatric patient. The use of CBCT for orthodontic analysis should be fully justified over conventional radiography and dose optimization to decrease thyroid dose is needed in pediatric patients.

• Imaging Science in Dentistry
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• 제37권2호
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• pp.93-102
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• 2007

Purpose: Cone beam computed tomography (CBCT) provides a lower dose and cost alternative to conventional CT, promising to revolutionize the practice of oral and maxillofacial radiology. The purpose of this study was to evaluate the absorbed and effective doses of Implagraphy and VCT (Vatech Co., Hwasung, Korea) and compare them with those of panoramic radiography. Materials and Methods: Thermoluminescent dosimeter (TLD) chips were placed at 27 sites throughout the layers of Female ART Head and Neck Phantom for dosimetry. Implagraphy, VCT units, and Planmeca Proline XC panoramic unit were used for radiation exposures. Radiation weighted doses and effective doses were measured and calculated using 1990 and 2005 ICRP tissue weighting factors. Results: Effective doses in Sv (ICRP 2005, ICRP 1990) were 90.19, 61.62 for Implagraphy at maxillay molar area, 123.20, 90.02 for Implagraphy at mandibular molar area, 183.55, 139.26 for VCT and 40.92, 27.16 for panoramic radiography. Conclusion: Effective doses for VCT and Implagraphy were only about 2.2 to 4.5 times greater than those for panoramic radiography. VCT and Implagraphy, CBCT machines recently developed in Korea, showed moderately low effective doses.

• Imaging Science in Dentistry
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• 제38권1호
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• pp.7-15
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• 2008

Purpose: This study provides comparative measurements of absorbed and effective doses for newly developed cone beam computed tomography (CT) in comparison with these doses for conventional CT. Materials and Methods: Thermoluminescent dosimeter rods (TLD rod: GR-200, Thermo Fisher Scientific Inc., Waltham, MA, USA) were placed at 25 sites throughout the layers of Male ART Head and Neck Phantom (Radiology Support Devices Inc., Long Beach, USA) for dosimetry. Implagraphy, DCT Pro (Vatech Co., Hwasung, Korea) units, SCT-6800TXL (Shimadzu Corp., Kyoto, Japan), and Crane x 3+(Soredex Orion Corp., Helsinki, Finland) were used for radiation exposures. Absorption doses were measured with Harshaw 3500TLD reader (Thermo Fisher Scientific Inc., Waltham, MA, USA). Radiation weighted doses and effective doses were measured and calculated by 2005 ICRP tissue weighting factors. Results: Absorbed doses in Rt. submandibular gland were 110.57 mGy for SCT 6800TXL (Implant), 24.56 mGy for SCT 6800TXL (3D), 22.39 mGy for Implagraphy 3, 7.19 mGy for DCT Pro, 5.96 mGy for Implagraphy 1, 0.70 mGy for Cranex 3+. Effective doses $(E_{2005draft)$ were 2.551 mSv for SCT 6800TXL (Implant), 1.272 mSv for SCT 6800TXL (3D), 0.598 mSv for Implagraphy 3, 0.428 mSv for DCT Pro and 0.146 mSv for Implagraphy 1. These are 108.6, 54.1, 25.5, 18.2 and 6.2 times greater than panoramic examination (Cranex 3+) doses (0.023mSv). Conclusion: Cone beam CT machines recently developed in Korea, showed lower effective doses than conventional CT. Cone beam CT provides a lower dose and cost alternative to conventional CT, promising to revolutionize the practice of oral and maxillofacial radiology.

• 대한방사선기술학회지:방사선기술과학
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• 제46권6호
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• pp.509-517
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• 2023

This study analyzed imaging conditions and exposure index through clinical information collection and dose calculation programs in coronary angiography examinations. Through this, we aim to analyze the effective dose according to examination conditions and provide basic data for dose optimization. In this study, ALARA(As Low As Reasonably Achievable)-F(Fluoroscopy), a program for evaluating the radiation dose of patients and the collected clinical data, was used. First, analysis of imaging conditions and exposure index was performed based on the data of the dose report generated after coronary angiography. Second, after evaluating organ dose according to 9 imaging directions during coronary angiography, with the LAO fixed at 30°, dose evaluation was performed according to tube voltage, tube current, number of frames, focus-skin distance, and field size. Third, the effective dose for each organ was calculated according to the tissue weighting factors presented in ICRP(International Commission on Radiological Protection) recommendations. As a result, the average sum of air kerma during coronary angiography was evaluated as 234.0±112.1 mGy, the dose-area product was 25.9±13.0 Gy·cm², and the total fluoroscopy time was 2.5±2.0 min. Also, the organ dose tended to increase as the tube voltage, milliampere-second, number of frames, and irradiation range increased, whereas the organ dose decreased as the FSD increased. Therefore, medical radiation exposure to patients can be reduced by selecting the optimal tube voltage and field size during coronary angiography, maximizing the focal-skin distance, using the lowest tube current possible, and reducing the number of frames.

• 대한디지털의료영상학회논문지
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• 제14권2호
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• pp.9-14
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• 2012

Exposed dose of young child should be managed necessarily. Young child is more sensitive than adult of a Radioactivity, especially, and lives longer than adult. Must reduce exposed dose which follows The ALARA(As Low As Reasonably Achievable)rule is recommended by ICRP(International Commission on Radiological Protection)within diagnostic useful range. Therefore, We have to prepare Pediatric DRL(Diagnostic Reference Level) in Korea as soon as possible. Consequently, in this study, wish to estimate organ dose and effective dose using PCXMC Program(a PC-Based Monte Carlo Program), and measure ESD(Entrance surface dose)and organ dose using Glass dosimeter, and then compare with DRL which follows EC(European Commission)and NRPB(National Radiological Protection Board). Using glass dosimeter and PCXMC programs conforming to the International Committee for Radioactivity Prevention(ICRP)-103 tissue weighting factor based on the item before the organs contained in the Chest, Skull, Pelvis, Abdomen in the organ doses and effective dose and dose measurements were evaluated convenience. In a straightforward way to RANDO phantom inserted glass dosimeter(GD352M)by using the hospital pediatric protocol, and in a indirect way was PCXMC the program through a virtual simulation of organ doses and effective dose were calculated. The ESD in Chest PA is 0.076mGy which is slightly higher than the DRL of NRPB(UK) is 0.07mGy, and is lower than the DRL of EC(Europe) which is 0.1mGy. The ESD in Chest Lateral is 0.130mGy which is lower than the DRL of EC(Europe) is 0.2mGy. The ESD in Skull PA is 0.423mGy which is 40 percent lower than the DRL of NRPB(UK) is 1.1mGy and is 28 percent lower than the DRL of EC(Europe) is 1.5mGy. The ESD in Skull Lateral is 0.478mGy which is half than the DRL of NRPB(UK) is 0.8mGy, is 40 percent lower than the DRL of EC(Europe) is 1mGy. The ESD in Pelvis AP is 0.293mGy which is half than the DRL of NRPB(UK) is 0.60mGy, is 30 percent lower than the DRL of EC(Europe)is 0.9mGy. Finally, the ESD in Abdomen AP is 0.223mGy which is half than the DRL of NRPB(UK) is 0.5mGy, and is 20 percent lower than the DRL of EC is 1.0mGy. The six kind of diagnostic radiological examination is generally lower than the DRL of NRPB(UK)and EC(Europe) except for Chest PA. Shouldn't overlook the age, body, other factors. Radiological technician must realize organ dose, effective dose, ESD when examining young child in hospital. That's why young child is more sensitive than adult of a Radioactivity.

• 한국식품과학회지
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• 제43권1호
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• pp.83-90
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• 2011

본 연구는 모시잎의 혈청, 간 및 지방조직의 체내 지질대사 개선 및 항비만 효과를 살펴보기 위하여 in vivo에서 5주령 된 흰쥐 수컷 24마리를 1주일간 적응시킨 후 정상 식이군(N), 고지방-고콜레스테롤 식이군(HFC), 고지방-고콜레스테롤 식이와 5% 모시잎 분말 첨가군(HFC-RL) 및 고지방-고콜레스테롤 식이와 10% 모시잎 분말 첨가군(HFC-RH)으로 나누어 4주간 실시하였다. 고지방-고콜레스테롤 식이로 인하여 체중이 유의적으로 증가하였으나, 모시잎 분말의 첨가 수준이 증가할수록 체중이 유의하게 감소하였다. 식이섭취량은 대조군(HFC)이 가장 낮았으며, 모시잎 분말 급여로 감소하는 경향이었다. 식이효율은 10% 모시잎 분말첨가로 유의하게 감소하여 정상 식이군(N)의 식이효율 수준과 유사하였다. 장간막지방조직과 부고환지방조직의 무게는 10% 모시잎 분말 첨가로 유의하게 감소하여 정상 식이군(N)보다 오히려 더 감소하는 경향을 보였다. 고지방-고콜레스테롤 식이로 증가되어진 혈청 중 AST, ALT, ALP 및 LDH 활성은 모시잎 분말 급여로 저하되었다. 혈청 중 중성지방 함량과 총콜레스테롤 함량도 고지방-고콜레스테롤 식이 급여로 증가되었으나, 모시잎 분말 첨가에 따라 농도 의존적으로 감소하였다. 고지방-고콜레스테롤 식이로 감소되어진 혈청 중 HDL-콜레스테롤 함량은 모시잎 분말 급여로 모두 유의하게 증가하였으며, 증가되어진 혈청 중 LDL-콜레스테롤 함량은 모두 유의하게 감소하였다. 동맥경화지수와 심혈관위험지수는 5%와 10%의 모시잎 분말 급여로 모두 유의하게 감소하였으며, 특히 10% 모시잎 분말을 급여하였을 경우 감소효과가 커 정상 식이군(N)과 유사한 경향이었다. 간조직 중 중성지방과 총콜레스테롤 함량은 모시잎 분말 급여로 모두 대조군(HFC)에 비하여 유의하게 감소하였다. 장간막지방조직과 부고환 지방조직의 중성지방 및 총콜레스테롤 함량도 모시잎 분말 급여로 유의하게 감소하였다. 지방조직의 HR-LPL과 TE-LPL 활성은 모시잎 분말의 첨가 급여로 농도 의존적으로 유의하게 감소하였다. 이상의 실험 결과 고지방-고콜레스테롤 식이와 함께 급여한 모시잎 분말은 체중, 간 및 지방조직의 무게 감소와 더불어 혈청 및 지방조직의 지질대사 개선에 긍정적인 영향을 미치는 것으로 나타났다. 이러한 결과는 모시잎 분말에 다량 함유된 식이섬유소와 클로로필 등의 생리활성 물질이 지질대사를 개선시키고 지방축적을 억제하여 고지혈증의 예방 및 치료효과와 비만을 억제하는 효과를 나타내 대사성 합병률과 심혈관계 질환의 발생을 감소시키는데 효과가 있을 것으로 생각되어진다. 그 외에 어떠한 생리활성 성분이 어떻게 작용을 하는지에 대해서는 추후 더 체계적인 연구가 필요할 것으로 사료된다.