• Title, Summary, Keyword: dose calculation

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Dose Determination in the IR-221 Gamma Facility Using a Monte Carlo Simulation (몬테칼로 시뮬레이션을 이용한 IR-221의 선량 평가)

  • Lim, Ik-Sung;Kim, Ki-Yup;Roh, Gyu-Hong;Lee, Chung
    • Journal of Radiation Protection and Research
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    • v.32 no.1
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    • pp.21-26
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    • 2007
  • This study is performed to evaluate the dose rate and to analyze the dose distribution of the gamma irradiation facility (IR-221) by using a Monte Calro simulation, which is helpful of upgrading the radiation processing qualification. Monte Cairo simulation is performed by MCNP4B code. Dose rates were measured at total 369 points with alanine dosimeters to compare the calculation results and the measurements data. The results have shown that the MCNP4B code is very useful to determine the dose distribution of the IR-221 gamma irradiation facility, as the calculation dose rate is within about ${\pm}5%$ of the measurement data. Dosimetry about the gamma irradiation facility usually needs enormous manpower and time. However Monte Cairo calculation method can reduce the tedious dosimetry jobs and improve the irradiation processing qualification, which will probably contribute to obtain the reliability of the irradiation products.

Radiation Analysis of Communications and Broadcasting Satellite

  • Park, Jae-Woo;Chung, Tae-Jin;Lee, Seong-Pal;Seon, Jong-Ho;Jeong, Yun-Whang
    • International Journal of Aeronautical and Space Sciences
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    • v.3 no.2
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    • pp.40-45
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    • 2002
  • A radiation analysis is performed for the Ka and Ku-band transponder of the Communications and Broadcasting Satellite (CBS) that is planned for launch into the geo-synchronous orbit. A particular attention is given to calculation of Total Ionizing Dose (TID) for the mission life time of 15 + 3 years. A numerical modeling of the charged particles at the geo-synchronous orbit is undertaken. The charged particles from the modeling are then transported through the mechanical structure and component housings of the transponder. A set of locations are selected for the detailed calculation of TID. The results from the present calculation show that three-dimensional modeling of the component housings as well as the mechanical structure of the spacecraft is requisite in order to acquire a reliable calculation of TID.

The Mediating Effect of Drug Calculation Confidence in the Relationship between Interest in Medication and Drug Calculation Competency (투약에 대한 흥미도와 약물계산역량 간의 관계에서 약물계산자신감의 매개효과: Kolb의 학습양식유형을 적용하여)

  • Park, Hyoung Sook;Cho, Gyoo Yeong;Kim, Dong-Hee;Kim, Sang Hee;Kim, Myoung Soo
    • Journal of Korean Biological Nursing Science
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    • v.15 no.4
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    • pp.155-163
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    • 2013
  • Purpose: The purpose of this study was to identify the mediating effect of confidence for drug calculation in the relationship between interest in medication and drug calculation competency using learning style. Methods: Participants in this study were 421 nursing students from Busan and Kyungnam province. The scales of learning style, interest in medication, importance of perception, confidence for drug calculation, and drug calculation competency for nursing students were used in this study. Descriptive statistics, $X^2$-test, t-test, Pearson correlation coefficient, and stepwise multiple regression were used for data analysis. Results: Learning styles of the participants were diverger 19.0%, accommodator 30.9%, converger 21.1%, and assimilator 29.0%. The drug dose calculation competency of participants was relatively low with a mean score 66.73. There were significant positive correlations among drug dose calculation competency, interest in medication (r=.31, p<.001), and confidence for drug calculation (r=.44, p<.001). Confidence for drug calculation was a moderator between interests in medication and drug calculation competency. Conclusion: Based on the result of this study, confidence for drug calculation promoting strategy such as medication reconciliation and various learning technology for improving drug calculation competency are needed.

Error Analysis of Delivered Dose Reconstruction Using Cone-beam CT and MLC Log Data (콘빔 CT 및 MLC 로그데이터를 이용한 전달 선량 재구성 시 오차 분석)

  • Cheong, Kwang-Ho;Park, So-Ah;Kang, Sei-Kwon;Hwang, Tae-Jin;Lee, Me-Yeon;Kim, Kyoung-Joo;Bae, Hoon-Sik;Oh, Do-Hoon
    • Progress in Medical Physics
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    • v.21 no.4
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    • pp.332-339
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    • 2010
  • We aimed to setup an adaptive radiation therapy platform using cone-beam CT (CBCT) and multileaf collimator (MLC) log data and also intended to analyze a trend of dose calculation errors during the procedure based on a phantom study. We took CT and CBCT images of Catphan-600 (The Phantom Laboratory, USA) phantom, and made a simple step-and-shoot intensity-modulated radiation therapy (IMRT) plan based on the CT. Original plan doses were recalculated based on the CT ($CT_{plan}$) and the CBCT ($CBCT_{plan}$). Delivered monitor unit weights and leaves-positions during beam delivery for each MLC segment were extracted from the MLC log data then we reconstructed delivered doses based on the CT ($CT_{recon}$) and CBCT ($CBCT_{recon}$) respectively using the extracted information. Dose calculation errors were evaluated by two-dimensional dose discrepancies ($CT_{plan}$ was the benchmark), gamma index and dose-volume histograms (DVHs). From the dose differences and DVHs, it was estimated that the delivered dose was slightly greater than the planned dose; however, it was insignificant. Gamma index result showed that dose calculation error on CBCT using planned or reconstructed data were relatively greater than CT based calculation. In addition, there were significant discrepancies on the edge of each beam while those were less than errors due to inconsistency of CT and CBCT. $CBCT_{recon}$ showed coupled effects of above two kinds of errors; however, total error was decreased even though overall uncertainty for the evaluation of delivered dose on the CBCT was increased. Therefore, it is necessary to evaluate dose calculation errors separately as a setup error, dose calculation error due to CBCT image quality and reconstructed dose error which is actually what we want to know.

Penumbra Effect on Integral Absorbed Dose in Co-60 Teletherapy

  • Moon, Philip S.
    • Nuclear Engineering and Technology
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    • v.5 no.2
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    • pp.87-93
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    • 1973
  • Due to the Co-60 source size, the penumbra in Co-60 teletheraphy poses a serious problem, even if the extended collimators are used, Here an empirical formula for the calculation of integral absorbed dose in the penumbra region was derived. Through a numerical calculation, the penumbra effect on integral absorbed dose was investigated. The longer the source-to-skin distance, the larger the integral absorbed dose of penumbra region, and the larger the source diameter, the larger the integral absorbed dose of penumbra region. It was also found that in some case the integral absorbed dose in penumbra region becomes several times larger than the integral absorbed dose of treatment region itself if the source-to-skin distance becomes greater. Therefore, one must consider the penumbra effect in Co-60 teletherapy.

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A fast gamma-ray dose rate assessment method for complex geometries based on stylized model reconstruction

  • Yang, Li-qun;Liu, Yong-kuo;Peng, Min-jun;Li, Meng-kun;Chao, Nan
    • Nuclear Engineering and Technology
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    • v.51 no.5
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    • pp.1436-1443
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    • 2019
  • A fast gamma-ray dose rate assessment method for complex geometries based on stylized model reconstruction and point-kernel method is proposed in this paper. The complex three-dimensional (3D) geometries are imported as a 3DS format file from 3dsMax software with material and radiometric attributes. Based on 3D stylized model reconstruction of solid mesh, the 3D-geometrical solids are automatically converted into stylized models. In point-kernel calculation, the stylized source models are divided into point kernels and the mean free paths (mfp) are calculated by the intersections between shield stylized models and tracing ray. Compared with MCNP, the proposed method can implement complex 3D geometries visually, and the dose rate calculation is accurate and fast.

Application of Generalized Batho Method to Arbitrary Shape of Heterogeneous Tissues (일반 Batho방법의 부정형 이질조직에의 적용)

  • Chai, Kyu-Young
    • Radiation Oncology Journal
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    • v.5 no.2
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    • pp.165-168
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    • 1987
  • The generalized Bathe method, proposed by Webb and Fox, which is a method of calculation of dose correction factor for the purpose of heterogeneous tissue, is complex even for a few kind of tissues. The method was modified for the purpose of getting a simple method that divide the multilayer of heterogeneous tissues into some groups of adjacent-tissue pairs. This new method could reduce the number of exponential terms and the time for calculating the dose correction factors by manual and computer calculation.

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Dose Calculation for the Buckler Remote Afterloading System (Buchler 강내조사장치의 선량계산에 대한 연구)

  • Chung Weon Kuu;Kim Soo Kon;Kang Jeong Ku;Lee Jeong Ok;Moon Sun Rock;Kim Seung Kon
    • Radiation Oncology Journal
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    • v.14 no.3
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    • pp.247-253
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    • 1996
  • Purpose : The dose calculation program for the Buckler type remote after-loading system was developed. This program also can be used to calculate dose for various sealed sources. Materials and Methods : We determined the source length and distribution by dividing the program disk to 72 points. The dose rate for the each program disk and source was calculated. The dose rate table for the xy coordinate was established. The dose rate for the interesting points of the patient were calculated by using this table, We also made isodose curve from this calculations. Results : The storage size for the dose rate table were increased. But the calculation of the dose rate for the patient were carried out rapidly. So we could get real time calculation. Conclusion : By using this program, we could calculate the dose rate for the various points of the patient quickly and accurately. This program will be useful for the treatment with various linear sources.

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Comparison of Dosimetric and Radiobiological Parameters on Plans for Prostate Stereotactic Body Radiotherapy Using an Endorectal Balloon for Different Dose-Calculation Algorithms and Delivery-Beam Modes

  • Kang, Sang-Won;Suh, Tae-Suk;Chung, Jin-Beom;Eom, Keun-Yong;Song, Changhoon;Kim, In-Ah;Kim, Jae-Sung;Lee, Jeong-Woo;Cho, Woong
    • Journal of the Korean Physical Society
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    • v.70 no.4
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    • pp.424-430
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    • 2017
  • The purpose of this study was to evaluate the impact of dosimetric and radiobiological parameters on treatment plans by using different dose-calculation algorithms and delivery-beam modes for prostate stereotactic body radiation therapy using an endorectal balloon. For 20 patients with prostate cancer, stereotactic body radiation therapy (SBRT) plans were generated by using a 10-MV photon beam with flattening filter (FF) and flattening-filter-free (FFF) modes. The total treatment dose prescribed was 42.7 Gy in 7 fractions to cover at least 95% of the planning target volume (PTV) with 95% of the prescribed dose. The dose computation was initially performed using an anisotropic analytical algorithm (AAA) in the Eclipse treatment planning system (Varian Medical Systems, Palo Alto, CA) and was then re-calculated using Acuros XB (AXB V. 11.0.34) with the same monitor units and multileaf collimator files. The dosimetric and the radiobiological parameters for the PTV and organs at risk (OARs) were analyzed from the dose-volume histogram. An obvious difference in dosimetric parameters between the AAA and the AXB plans was observed in the PTV and rectum. Doses to the PTV, excluding the maximum dose, were always higher in the AAA plans than in the AXB plans. However, doses to the other OARs were similar in both algorithm plans. In addition, no difference was observed in the dosimetric parameters for different delivery-beam modes when using the same algorithm to generate plans. As a result of the dosimetric parameters, the radiobiological parameters for the two algorithm plans presented an apparent difference in the PTV and the rectum. The average tumor control probability of the AAA plans was higher than that of the AXB plans. The average normal tissue complication probability (NTCP) to rectum was lower in the AXB plans than in the AAA plans. The AAA and the AXB plans yielded very similar NTCPs for the other OARs. In plans using the same algorithms, the NTCPs for delivery-beam modes showed no differences. This study demonstrated that the dosimetric and the radiobiological parameters for the PTV and the rectum affected the dose-calculation algorithms for prostate SBRT using an endorectal balloon. However, the dosimetric and the radiobiological parameters in the AAA and the AXB plans for other OARs were similar. Furthermore, difference between the dosimetric and the radiobiological parameters for different delivery-beam modes were not found when the same algorithm was used to generate the treatment plan.