• Title/Summary/Keyword: Cross Calibration

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Cross Calibration of Dual Energy X-ray Absorptiometry Equipment for Diagnosis of Osteoporosis: between Domestic Manufacturers and Global Manufacturers (골밀도 장치의 교차분석 ; 국내 제조사와 해외 제조사 비교)

  • Kim, Jung-Su
    • Journal of the Korean Society of Radiology
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    • v.12 no.7
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    • pp.833-844
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    • 2018
  • Dual energy X-ray absorptiometry is mainly used as an X-ray test method. For equipment manufactured GE and Hologic, cross-calibration analyses (CCA) of machines from the same manufacturer and between units from different manufacturers have been conducted, but the CCA of equipment manufactured in Korea are inadequate. Through CCA, we present a formula of the intersections between the Korean medical equipment company (KEC) with GE and Hologic manufactured DXA, and among the KEC DXA. The CCA was conducted for the European Spine Phantom on DXA from four KEC and three global medical equipment company (GEC) manufacturers. We compared bone mineral density (BMD) values and calculated the CCA equation by linear regression analysis. The standard-deviations (SD) of the BMD values were highest for the Dexxum T for the low, medium, and high spine, which were 0.030, 0.029, and 0.037, respectively. The smallest SD in the low and medium vertebrae were 0.005 and 0.004 for the Horizon Ci, respectively, and 0.005 for the Osteo Pro Max in the high vertebrae. Based on the intersection equations of the KEC DXA established in this study, CCA of various KEC DXA should be established for more accurate follow-up of BMD tests in clinical environments.

Developing Customized Phantom for Korean Bone Density Using 3D Printing (3D 프린팅을 이용한 한국인 골밀도 맞춤 팬텀 개발)

  • Lee, Junho;Choi, Kwan-Yong;Choi, Jae-Ho
    • Journal of radiological science and technology
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    • v.42 no.3
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    • pp.223-229
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    • 2019
  • In order to reduce the radiation exposure dose of the patient and to obtain accurate diagnosis results, the quality control of the diagnostic radiation generator must be conducted periodically In particular, bone density test equipment could be influenced by many factors, and it is far more important because inaccurate measurement would eventually affect the result value. However, the cross-correction phantom of DXA equipment is poorly penetrated due to lack of awareness of the industry and the high cost. Therefore, this study developed a BMD phantom using a 3D printer and Korean BMD phantom with low cost by cross analyzing Korean BMD value from The Korean National Health and Nutrition Examination Survey and evaluated it. The L1, L2, and L3 BMD values of phantoms produced with the 3D printer were measured to be $0.887{\pm}0.006g/cm^2$, $0.927{\pm}0.006g/cm^2$, and $0.960{\pm}0.005g/cm^2$, at 215 mm height and $0.882{\pm}0.011g/cm^2$, $0.914{\pm}0.005g/cm^2$, $0.933{\pm}0.008g/cm^2$ at 155 mm height displaying statistically significant relevance. The result suggests that a proper quality control and cross calibration of DXA device be possible and expected to be an essential data for various medical phantom manufacture development using 3D printer.

Study on Absorbed Dose Determination of Electron Beam Quality for Cross-calibration with Plane-parallel Ionization Chamber (평행평판형이온함의 교차교정 시 전자선 선질에 따른 흡수선량 결정에 대한 연구)

  • Rah, Jeong-Eun;Shin, Dong-Oh;Park, So-Hyun;Jeong, Ho-Jin;Hwang, Ui-Jung;Ahn, Sung-Hwan;Lim, Young-Kyung;Kim, Dong-Wook;Yoon, Myong-Geun;Shin, Dong-Ho;Lee, Se-Byeong;Suh, Tae-Suk;Park, Sung-Yong
    • Progress in Medical Physics
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    • v.20 no.2
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    • pp.97-105
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    • 2009
  • Absorbed dose to water based protocols recommended that plane-parallel chambers be calibrated against calibrated cylindrical chambers in a high energy electron beam with $R_{50}$>7 $g/cm^2$ (E${\gtrsim}$16 MeV). However, such high-energy electron beams are not available at all radiotherapy centers. In this study, we are compared the absorbed dose to water determined according to cross-calibration method in a high energy electron beam of 16 MeV and in electron beam energies of 12 MeV below the cross-calibration quality remark. Absorbed dose were performed for PTW 30013, Wellhofer FC65G Farmer type cylindrical chamber and for PTW 34001, Wellhofer PPC40 Roos type plane-parallel chamber. The cylindrical and the plane-parallel chamber to be calibrated are compared by alternately positioning each at reference depth, $Z_{ret}=0.6R_{50}-0.1$ in water phantom. The $D_W$ of plane-parallel chamber are derived using across-calibration method at high-energy electron beams of 16, 20 MeV. Then a good agreement is obtained the $D_W$ of plane-parallel chamber in 12 MeV. The agreement between 20 MeV and 12 MeV are within 0.2% for IAEA TRS-398.

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THE ANALYSIS OF ADEOS / POLDER DATA

  • Kawata, Yoshiyuki;Izumiya, Toshiaki;Takano, Yuichi;Yamazaki, Akihiro
    • Proceedings of the KSRS Conference
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    • pp.231-235
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    • 1998
  • We have made the cross calibration in terms of space reflectance between POLDER and OCTS sensors on board ADEOS satellite, using the POLDER and OCTS data acquired simultaneously on April 24, 1997. The space reflectance values for the same target computed from the POLDER and OCTS data are in very good agreement, when we adopted the new calibration coefficients of OCTS suggested by the vicarious experiment by NASDA. Then, we estimated aerosol parameters for several target areas (two areas in the Sea of Japan and three in the Pacific Ocean) from ADEOS/POLDER's directional reflectance and polarization data in 760nm and 865nm bands. A single atmospheric layer model with an isotropic Gaussian type ocean surface (Cox-Munk model) was assumed in this study.

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The Efficiency of BMD Cross-calibration for each different DEXA-System and Measurement of Precision used by Phantom (Phantom를 이용한 Precision의 측정과 서로 다른 DEXA System의 BMD 교차보정의 유용성)

  • Lee seung un;Choi yu jin;Lee pyeong jae;Kwon young he;Jung sun sun;Seo kil won;Whang seung yeon
    • Journal of The Korean Radiological Technologist Association
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    • v.30 no.1
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    • pp.41-48
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    • 2004
  • To know the Difference of BMD value actually measured by the Hologic equipment and the Lunar equipment that is the latest machine due to the acknowledgement for the difference of value when the follow-up test was performed by other different equipment aft

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ESA Earth Observation Programmes and International Cooperation in the frame of Third Party Missions

  • Hoersch B.;Laur H.;Kohlhammer G.
    • Proceedings of the KSRS Conference
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    • pp.598-600
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    • 2004
  • In Europe most Earth Observation (EO) data users rely on several EO missions, both to increase sustainability of their service and to widen the range of observation parameters. In addition to its own missions such as ERS 1 &2, ENVISAT and the Earth Explorers, ESA therefore offers access to the scientific and applications community to so-called 'Third Party Missions'. Third Party (TP) missions are complementing the observations of ESA missions, are used to prepare for future ESA missions including cross-calibration and create synergy to favor a wider use of EO data within ESA Member States.

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DESIGN AND DEVELOPMENT OF THE COMPACT AIRBORNE IMAGING SPECTROMETER SYSTEM

  • Lee, Kwang-Jae;Yong, Sang-Soon;Kim, Yong-Seung
    • Proceedings of the KSRS Conference
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    • pp.118-121
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    • 2007
  • In recent years, the hyperspectral instruments with high spatial and high spectral resolution have become an important component of wide variety of earth science applications. The primary mission of the proposed Compact Airborne Imaging Spectrometer System (CAISS) in this study is to acquire and provide full contiguous spectral information with high quality spectral and spatial resolution for advanced applications in the field of remote sensing. The CAISS will also be used as the vicarious calibration equipment for the cross-calibration of satellite image data. The CAISS consists of six physical units: the camera system, the Jig, the GPS/INS, the gyro-stabilized mount, the operating system, and the power inverter and distributor. Additionally, the calibration instruments such as the integrated sphere and spectral lamps are also prepared for the radiometric and spectral calibration of the CAISS. The CAISS will provide high quality calibrated image data that can support evaluation of satellite application products. This paper summarizes the design, development and major characteristic of the CAISS.

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Uncertainty Assessment: Relative versus Absolute Point Dose Measurement for Patient Specific Quality Assurance in EBRT

  • Mahmood, Talat;Ibrahim, Mounir;Aqeel, Muhammad
    • Progress in Medical Physics
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    • v.28 no.3
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    • pp.111-121
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    • 2017
  • Verification of dose distribution is an essential part of ensuring the treatment planning system's (TPS) calculated dose will achieve the desired outcome in radiation therapy. Each measurement have uncertainty associated with it. It is desirable to reduce the measurement uncertainty. A best approach is to reduce the uncertainty associated with each step of the process to keep the total uncertainty under acceptable limits. Point dose patient specific quality assurance (QA) is recommended by American Association of Medical Physicists (AAPM) and European Society for Radiotherapy and Oncology (ESTRO) for all the complex radiation therapy treatment techniques. Relative and absolute point dose measurement methods are used to verify the TPS computed dose. Relative and absolute point dose measurement techniques have a number of steps to measure the point dose which includes chamber cross calibration, electrometer reading, chamber calibration coefficient, beam quality correction factor, reference conditions, influences quantities, machine stability, nominal calibration factor (for relative method) and absolute dose calibration of machine. Keeping these parameters in mind, the estimated relative percentage uncertainty associated with the absolute point dose measurement is 2.1% (k=1). On the other hand, the relative percentage uncertainty associated with the relative point dose verification method is estimated to 1.0% (k=1). To compare both point dose measurement methods, 13 head and neck (H&N) IMRT patients were selected. A point dose for each patient was measured with both methods. The average percentage difference between TPS computed dose and measured absolute relative point dose was 1.4% and 1% respectively. The results of this comparative study show that while choosing the relative or absolute point dose measurement technique, both techniques can produce similar results for H&N IMRT treatment plans. There is no statistically significant difference between both point dose verification methods based upon the t-test for comparing two means.

Vicarious Radiometric Calibration of RapidEye Satellite Image Using CASI Hyperspectral Data (CASI 초분광 영상을 이용한 RapidEye 위성영상의 대리복사보정)

  • Chang, An Jin;Choi, Jae Wan;Song, Ah Ram;Kim, Ye Ji;Jung, Jin Ha
    • Journal of Korean Society for Geospatial Information Science
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    • v.23 no.3
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    • pp.3-10
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    • 2015
  • All kinds of objects on the ground have inherent spectral reflectance curves, which can be used to classify the ground objects and to detect the target. Remotely sensed data have to be transferred to spectral reflectance for accurate analysis. There are formula methods provided by the institution, mathematical model method and ground-data-based method. In this study, RapidEye satellite image was converted to reflectance data using spectral reflectance of a CASI hyperspectral image by using vicarious radiometric calibration. The results were compared with those of the other calibration methods and ground data. The proposed method was closer to the ground data than ATCOR and New Kurucz 2005 method and equal with ELM method.

A Study of Equipment Accuracy and Test Precision in Dual Energy X-ray Absorptiometry (골밀도검사의 올바른 질 관리에 따른 임상적용과 해석 -이중 에너지 방사선 흡수법을 중심으로-)

  • Dong, Kyung-Rae;Kim, Ho-Sung;Jung, Woon-Kwan
    • Journal of radiological science and technology
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    • v.31 no.1
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    • pp.17-23
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    • 2008
  • Purpose : Because there is a difference depending on the environment as for an inspection equipment the important part of bone density scan and the precision/accuracy of a tester, the management of quality must be made systematically. The equipment failure caused by overload effect due to the aged equipment and the increase of a patient was made frequently. Thus, the replacement of equipment and additional purchases of new bonedensity equipment caused a compatibility problem in tracking patients. This study wants to know whether the clinical changes of patient's bonedensity can be accurately and precisely reflected when used it compatiblly like the existing equipment after equipment replacement and expansion. Materials and methods : Two equipments of GE Lunar Prodigy Advance(P1 and P2) and the Phantom HOLOGIC Spine Road(HSP) were used to measure equipment precision. Each device scans 20 times so that precision data was acquired from the phantom(Group 1). The precision of a tester was measured by shooting twice the same patient, every 15 members from each of the target equipment in 120 women(average age 48.78, 20-60 years old)(Group 2). In addition, the measurement of the precision of a tester and the cross-calibration data were made by scanning 20 times in each of the equipment using HSP, based on the data obtained from the management of quality using phantom(ASP) every morning (Group 3). The same patient was shot only once in one equipment alternately to make the measurement of the precision of a tester and the cross-calibration data in 120 women(average age 48.78, 20-60 years old)(Group 4). Results : It is steady equipment according to daily Q.C Data with $0.996\;g/cm^2$, change value(%CV) 0.08. The mean${\pm}$SD and a %CV price are ALP in Group 1(P1 : $1.064{\pm}0.002\;g/cm^2$, $%CV=0.190\;g/cm^2$, P2 : $1.061{\pm}0.003\;g/cm^2$, %CV=0.192). The mean${\pm}$SD and a %CV price are P1 : $1.187{\pm}0.002\;g/cm^2$, $%CV=0.164\;g/cm^2$, P2 : $1.198{\pm}0.002\;g/cm^2$, %CV=0.163 in Group 2. The average error${\pm}$2SD and %CV are P1 - (spine: $0.001{\pm}0.03\;g/cm^2$, %CV=0.94, Femur: $0.001{\pm}0.019\;g/cm^2$, %CV=0.96), P2 - (spine: $0.002{\pm}0.018\;g/cm^2$, %CV=0.55, Femur: $0.001{\pm}0.013\;g/cm^2$, %CV=0.48) in Group 3. The average error${\pm}2SD$, %CV, and r value was spine : $0.006{\pm}0.024\;g/cm^2$, %CV=0.86, r=0.995, Femur: $0{\pm}0.014\;g/cm^2$, %CV=0.54, r=0.998 in Group 4. Conclusion: Both LUNAR ASP CV% and HOLOGIC Spine Phantom are included in the normal range of error of ${\pm}2%$ defined in ISCD. BMD measurement keeps a relatively constant value, so showing excellent repeatability. The Phantom has homogeneous characteristics, but it has limitations to reflect the clinical part including variations in patient's body weight or body fat. As a result, it is believed that quality control using Phantom will be useful to check mis-calibration of the equipment used. A value measured a patient two times with one equipment, and that of double-crossed two equipment are all included within 2SD Value in the Bland - Altman Graph compared results of Group 3 with Group 4. The r value of 0.99 or higher in Linear regression analysis(Regression Analysis) indicated high precision and correlation. Therefore, it revealed that two compatible equipment did not affect in tracking the patients. Regular testing equipment and capabilities of a tester, then appropriate calibration will have to be achieved in order to calculate confidential BMD.

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