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박소아,강세권,정광호,황태진,윤재웅,Taeryool Koo,한태진,김해영,이미연,배훈식,김경주 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.2
EBT3 film is utilized as a dosimetry quality assurance tool for the verification of clinical radiotherapy treatments. In this work, we suggest a percentage-depth-dose (PDD) calibration method that can calibrate several EBT3 film pieces together at different dose levels because photon beams provide different dose levels at different depths along the axis of the beam. We investigated the feasibility of the film PDD calibration method based on PDD data and compared the results those from the traditional film calibration method. Photon beams at 6 MV were delivered to EBT3 film pieces for both calibration methods. For the PDD-based calibration, the film pieces were placed on solid phantoms at the depth of maximum dose (dmax) and at depths of 3, 5, 8, 12, 17, and 22 cm, and a photon beam was delivered twice, at 100 cGy and 400 cGy, to extend the calibration dose range under the same conditions. Fourteen film pieces, to maintain their consistency, were irradiated at doses ranging from approximately 30 to 400 cGy for both film calibrations. The film pieces were located at the center position on the scan bed of an Epson 1680 flatbed scanner in the parallel direction. Intensity-modulated radiation therapy (IMRT) plans were created, and their dose distributions were delivered to the film. The dose distributions for the traditional method and those for the PDD-based calibration method were evaluated using a Gamma analysis. The PDD dose values using a CC13 ion chamber and those obtained by using a FC65-G Farmer chamber and measured at the depth of interest produced very similar results. With the objective test criterion of a 1% dosage agreement at 1 mm, the passing rates for the four cases of the three IMRT plans were essentially identical. The traditional and the PDD-based calibrations provided similar plan verification results. We also describe another alternative for calibrating EBT3 films, i.e., a PDD-based calibration method that provides an easy and time-saving approach to film calibration.
Feasibility of an In-House Phantom for Mechanical and Geometrical QA
박소아,강세권,정광호,황태진,윤재웅,구태률,한태진,김해영,이미연,배훈식,김경주 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.72 No.3
We designed an in-house phantom for mechanical quality assurance (QA) and compared itsperformance against commercial available QA tools. The QA phantom is an acrylic cubic shapewith dimensions of 150 mm × 150 mm × 150 mm, and with a pocket into which various adapterplates can be inserted. The plates were classified into three types (A, B, and C) according to theirlocation and shape. An additional accessory can be used to check the alignment of lasers to thecenter of CT image scans. We evaluated the usefulness of the phantom by checking mechanicalisocentricity, field size accuracy, isocenter and position coincidence between the treatment beamand the image guidance systems, and alignment of the lasers. All the tests carried out were withinthe tolerance limits. The isocenter of the gantry and collimator was within 1 mm and the fieldsize was within 2 mm for both the commercial tool and the new phantom. The kV image of theisocenter was within 0.5 mm for both the commercial tool and the new phantom and that of thedisplacement of the off-center position from the isocenter was within 0.5 mm for both phantoms. Displacement between the laser origin and the center of a CT image scan was within 0.5 mm for thecommercial tool and new phantom. The developed phantom can also be used to easily check thegeometrical and mechanical parameters of medical linear accelerators (LINAC) and CT simulators.
Absorption Spectrum of Gafchromicr EBT2 Film with Angular Rotation
박소아,정광호,황태진,윤제웅,한태진,김해영,이미연,김경주,배훈식,강세권,오성재,허영민,서진석 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.1
Study of the absorption spectrum in film dosimetry is important because the spectral absorbance of the film is related to the film’s total absorption dose. We investigated the absorption spectra of Gafchromic EBT2 film at various rotational angles in a visible wavelength band. The film was irradiated with 6-MV photon beams for a total dose of 300 cGy. The absorption spectra for different angles of rotation were obtained 24 h after the irradiation and we fitted the spectra by using Lorentzian functions. Two dominant absorption peaks, one at approximately 586 nm (green) and the other at 634 nm (red) were observed. The measured spectrum was decomposed into peaks at 542 nm, 558 nm, 578 nm, 586 nm, 626 nm, 634 nm, and 641 nm. The maximum total area of the red absorption band occurred at 45 (225) and the minimum at 90 (270). As the angle of rotation changed, the intensities and integrated areas of the blue and the green peaks also changed with a 180 period, with minima at 90 and 270, and maxima at 0 and 180, although the overall absorbance was very low. The spectral peak wavelengths remained constant within ±1.2 nm for all angles. The absorption spectrum of the film should no hysteresis of; spectra taken at 0 and 360 were substantially the same and showed similar behaviors for all rotational angles. The change in the absorbance with the rotational angle of the film affected the dosimetric properties, resulting in rotational variations of the film’s dosimetry in each red-green-blue channel.
소아 크룹 입원 환자의 병인과 계절적 변동: 6년간의 다기관 후향적 연구(2010–2015년)
이용주,김효빈,김봉성,김창근,김철홍,김형영,김상영,김윤선,박초롱,서주희,설인숙,성명순,송민섭,송대진,안영민,오혜린,유진호,이경석,이 은,이주석,장광천,장윤영,정은희,정혜리,최성민,최윤정,한만용,양현종,심정연,김진택,대한 소아알레르기 호흡기학회 폐렴·호흡기질환 연구회 대한 소아알레르기 호흡기학회 2019 Allergy Asthma & Respiratory Disease Vol.7 No.2
Purpose: Croup is known to have epidemics in seasonal and biennial trends, and to be strongly associated with epidemics of parainfluenza virus. However, seasonal and annual epidemics of croup have not been clearly reported in Korea. This study aimed to examine the seasonal/annual patterns and etiologies of childhood croup in Korea during a consecutive 6-year period. Methods: Pediatric croup data were collected from 23 centers in Korea from 1 January 2010 to 31 December 2015. Electronic medical records, including multiplex reverse transcription polymerase chain reaction (RT-PCR) results, demographics and clinical information were cross-sectionally reviewed and analyzed. Results: Overall, 2,598 childhood croup patients requiring hospitalization were identified during the study period. Among them, a total of 927 who underwent RT-PCR were included in the analysis. Males (61.5%) predominated, and most (63.0%) of them were younger than 2 years of age (median, 19 months; interquartile range, 11–31 months). Peak hospitalization occurred in 2010 and 2012 in even-numbered years, and parainfluenza virus (PIV, 39.7%) was the most common cause of childhood croup requiring hospitalization, followed by respiratory syncytial virus (14.9%), human rhinovirus (12.5%), Mycoplasma pneumonaie (10.6%), and human coronavirus (7.3%). Conclusion: It is concluded that croup hospitalization has a biennial pattern in even-numbered years. PIV may be the most common cause of childhood croup; however, croup epidemics could be attributed to other viruses.
최봉석,김현희,김효빈,나영호,박 양,성명순,신윤호,염혜영,이경석,이용주,전윤홍,지혜미,김민지,박용민,최선희,대한 소아알레르기 호흡기학회 비염연구회 대한 소아알레르기 호흡기학회 2022 Allergy Asthma & Respiratory Disease Vol.10 No.4
The prevalence of allergic rhinitis in children and adolescents is constantly increasing. However, few studies exist on the relationship between smoking and allergic rhinitis. In addition to conventional cigarettes, electronic and heated cigarettes have recently been introduced, which have several harmful effects. It is hypothesized that smoking and rhinitis are correlated; however, this relationship is complex. Previous studies reported that exposure to smoking during pregnancy is associated with allergic rhinitis development. Unlike the varied results reported in adults, studies on children and adolescents have often correlated direct/indirect smoke with allergic rhinitis, with prolonged exposure being associated with a higher risk of allergic rhinitis, particularly when exposed at an early age. Nonallergic inflammatory reactions and immunoglobulin E-mediated allergic sensitization are assumed to be the underlying mechanisms for the association between allergic rhinitis and smoking. Measures to reduce smoking are warranted to lower the incidence of allergic rhinitis in children and adolescents and to improve their health.
박소아(So-Ah Park),채철주(Cheol-Joo Chae),조한진(Han-Jin Cho),이재광(Jae-Kwang Lee) 한국콘텐츠학회 2012 한국콘텐츠학회논문지 Vol.12 No.2
현재 전자입찰시스템에서 사용자 인증은 패스워드 기반의 PKI 기술을 사용하고 있다. 패스워드 기반 PKI 기술의 경우 개인키를 사용자가 기억하기 쉬운 패스워드를 이용하여 보호하고 있기 때문에 패스워드 노출에 대한 문제점을 가지고 있다. 또한 전자입찰시스템에서 타인의 공인인증서를 이용한 불법적인 사용이 증가하고 있다. 최근 이러한 문제점을 해결하기 위해 바이오 인식을 이용한 PKI 기술에 대한 연구가 활발히 진행되고 있다. 바이오 인증을 위해 사용자가 입력한 바이오 정보를 템플릿으로 변환하게 되면 기존의 인증기술보다 보안성이 강화된 사용자 인증 방식을 구축할 수 있다. 그러므로 본 논문에서는 바이오 인식에서 가장 많이 사용하고 있는 지문 정보를 이용하여, 지문보안토큰에 사용자 지문 정보와 인증서를 저장하여 사용자를 인증할 수 있는 전자입찰시스템을 설계 및 구현하였다. 본 논문에서 제안한 지문 정보를 이용한 공개키 기반의 전자입찰시스템을 사용할 경우 사용자 인증 강화뿐만 아니라 전자입찰시스템에서 타인의 인증서를 이용한 대리인 입찰 문제를 해결할 수 있다. In the case of the password-based PKI technology, because it protects by using the password which is easy that user memorizes the private key, he has the problem about the password exposure. In addition, in the system of electronic bidding, the illegal use using the authentic certificate of the others increases. Recently, in order to solve this problem, the research about the PKI technology using the biometrics is actively progressed. If the bio information which the user inputs for the bio authentication is converted to the template, the digest access authentication in which the security is strengthened than the existing authentication technology can be built. Therefore, in this paper, we had designed and developed the system of electronic bidding which it uses the most widely used fingerprint information in the biometrics, it stores the user fingerprint information and certificate in the fingerprint security token and can authenticate the user. In case of using the system of electronic bidding of the public key infrastructure using the fingerprint information proposed in this paper the agent bid problem that it uses the certificate of the others in not only user authentication intensification but also system of electronic bidding can be concluded.