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Journal Articles

Application of voxel phantoms and Monte Carlo method to whole-body counter calibrations

Kinase, Sakae; Takagi, Shunji*; Noguchi, Hiroshi; Saito, Kimiaki

Radiation Protection Dosimetry, 125(1-4), p.189 - 193, 2007/07

 Times Cited Count:16 Percentile:74.96(Environmental Sciences)

In the Japan Atomic Energy Research Institute (JAERI), a calculation code -UCWBC code- for whole-body counter calibrations using voxel phantoms has been developed as an EGS4 Monte Carlo user code. To validate the UCWBC code for calibrating whole-body counters in JAERI, response functions and counting efficiencies of a p-type high-purity Ge semiconductor detector used for the whole-body counter were evaluated for a water-filled block-shape phantom by the UCWBC code and were measured by experiments. Furthermore, counting efficiencies of the Ge semiconductor detector for the male and female voxel phantoms developed in JAERI were evaluated in the photon energy range 60-1836 keV by the UCWBC code in order to examine the differences between the counting efficiencies for voxel phantoms. In conclusion, it was found that the response functions and counting efficiencies of the Ge semiconductor detector by the UCWBC code for the water-filled block-shape phantom are in good agreement with measured data. The UCWBC code was validated by the comparisons.

Journal Articles

Comparison of synchrotron radiation calculations between analytical codes(STAC8,PHOTON) and Monte Carlo codes (FLUKA,EGS4)

Liu, J. C.*; Fasso, A.*; Prinz, A.*; Rokni, S.*; Asano, Yoshihiro

Radiation Protection Dosimetry, 116(1-4), p.658 - 661, 2005/12

 Times Cited Count:6 Percentile:42.45(Environmental Sciences)

no abstracts in English

Journal Articles

Application of EGS4 code to evaluation of specific absorbed fractions and S values for internal dosimetry

Kinase, Sakae

KEK Proceedings 2005-3, p.292 - 297, 2005/06

The EGS4 code was used for evaluating the absorbed fraction per unit mass of the target organ-specific absorbed fraction (SAF)- and the mean absorbed dose to the target organ per unit cumulated activity in the source organ (S value) for internal dosimetry. The SAFs and S values were evaluated on a mathematical phantom (MIRD 5 type phantom) and Japanese adult voxel phantoms (Otoko and Onago phantoms) developed at the Japan Atomic Energy Research Institute (JAERI). The evaluated SAFs and S values were compared with several published data in order to demonstrate the use of the EGS4 code for the internal dosimetry and investigate the influence of certain parameters, such as the organ masses, on SAFs and S values. It was demonstrated that the EGS4 code is useful in the evaluation of the SAFs and S values for the internal dosimetry. It was also found that the SAFs and S values for organ self-absorption depend on the organ masses and would be affected by differences in the structure of the human body.

Journal Articles

Calculation of spatial distribution of dose rate for air under 300keV electron beam irradiation using a Monte Carlo code (EGS4-SPG code)

Hakoda, Teruyuki; Hanaya, Hiroaki; Kaneko, Hirohisa; Miyashita, Atsumi; Kojima, Takuji

Radioisotopes, 54(6), p.161 - 168, 2005/06

no abstracts in English

Journal Articles

Evaluation of counting efficiency of whole-body counter using voxel phantoms

Kinase, Sakae; Takagi, Shunji*; Noguchi, Hiroshi; Saito, Kimiaki

Proceedings of 11th International Congress of the International Radiation Protection Association (IRPA-11) (CD-ROM), 7 Pages, 2004/05

The present study was performed to validate the UCWBC code for calibrating in vivo measurements. Furthermore, the calibration data for the adult voxel phantoms developed in JAERI were evaluated by the UCWBC code in order to examine the differences between the calibration data for voxel phantoms, including a voxel version of water-filled block-shape phantom based on an actual phantom that is used for the calibration of the whole-body counter in JAERI. It was found that the calculated calibration data by the UCWBC code for the water-filled block-shape phantom show good agreement with measured ones. Consequently, the UCWBC code was validated by the comparisons. It was also found that the calibration data depend on phantoms of different sizes and the effective distance between phantom and detector. The calibration of in vivo measurements using voxel phantoms for individuals would be quite useful for the improvement in accuracy of the measurement results.

Journal Articles

Evaluation of S values for beta-ray emitters in voxel phantoms

Kinase, Sakae; Zankl, M.*; Funabiki, Jun*; Noguchi, Hiroshi; Saito, Kimiaki

KEK Proceedings 2003-15, p.45 - 52, 2004/02

no abstracts in English

Journal Articles

Development of EGS4-UCDOD user code for design and optimization of $$gamma$$ ray detection systems

Oishi, Tetsuya

RIST News, (36), p.12 - 20, 2003/10

no abstracts in English

Journal Articles

Evaluation of specific absorption fractions in voxel phantoms using Monte Carlo simulation

Kinase, Sakae; Zankl, M.*; Kuwabara, Jun; Sato, Kaoru; Noguchi, Hiroshi; Funabiki, Jun*; Saito, Kimiaki

Radiation Protection Dosimetry, 105(1-4), p.557 - 563, 2003/09

 Times Cited Count:25 Percentile:83.46(Environmental Sciences)

There exists a need to calculate specific absorbed fractions (SAFs) in voxel phantoms for internal dosimetry. For this purpose, an EGS4 user code for calculating SAFs using voxel phantoms was developed on the basis of an existing EGS4 user code for external dosimetry (UCPIXEL). In the developed code, the transport of photons, electrons and positrons in voxel phantoms can be simulated, particularly the transport simulations of secondary electrons in voxel phantoms can be made. The evaluated SAFs for the GSF Child voxel phantom using the developed code were found to be in good agreement with the GSF evaluated data. In addition, SAFs in adult voxel phantoms developed at JAERI were evaluated using the developed code and were compared with several published data. It was found that SAFs for organ self-absorption depend on the organ masses and would be affected by differences in the structure of the human body.

Journal Articles

Application of a Ge semi-conductor detector to whole-body counter

Kinase, Sakae; Noguchi, Hiroshi; Nakamura, Takashi*

Radiation Protection Dosimetry, 105(1-4), p.467 - 472, 2003/09

 Times Cited Count:4 Percentile:32.68(Environmental Sciences)

To calibrate a whole-body counter, it is necessary to find a determination method for peak efficiencies of detectors that the whole-body counter has. For the purpose, peak efficiencies of a Ge semi-conductor detector for point sources and volume sources were evaluated in the photon energy range of 60-1,836 keV by Monte Carlo simulation and experiment. It was found that the calculated peak efficiency curves as a function of energy without modeling the actual sensitive region of the detector are similar in shape to those measured. The calculated peak efficiencies of the detector that has an apparent dead layer (1mm) were also found to agree with the experimental values. Consequently, the simulation method for peak efficiencies was validated. In addition, an optimum design for a whole-body counter with Ge semi-conductor detectors was examined by simulation. This simulation enables to provide a method to determine an optimum arrangement of detectors in a whole-body counter offering a uniform response to various Cs-137 distributions in a human body.

Journal Articles

An EGS4 user code developed for design and optimization of $$gamma$$-ray detection systems

Oishi, Tetsuya; Tsutsumi, Masahiro; Sugita, Takeshi*; Yoshida, Makoto

Journal of Nuclear Science and Technology, 40(6), p.441 - 445, 2003/06

 Times Cited Count:1 Percentile:11.39(Nuclear Science & Technology)

An EGS4 user code has been developed to design and optimize $$gamma$$ ray detection systems for several types of radiation sources. The code is fundamentally based on the PRESTA-CG, which is improved on the electron transport in the EGS4 and specialized for the utilization of a combinatorial geometry (CG) method. The main additional functions in the present user code are classified into two parts of the definition of radiation sources and the transport of photons. The developed user code was applied to two types of detection systems in order to demonstrate its availability. As the result, it was found that the present code allows the detailed response analysis of complicated detection systems for several sources with just a simple handling.

JAEA Reports

Study on advancement of ${it in vivo}$ counting using mathematical simulation

Kinase, Sakae

JAERI-Research 2003-011, 104 Pages, 2003/05

JAERI-Research-2003-011.pdf:5.11MB

In the present study, a calibration technique for in vivo counting application using Monte Carlo simulation was developed. The advantage of the technique is that counting efficiency can be obtained for various shapes, sizes that is very difficult to change for phantoms. The method for the determination of counting efficiency curves as a function of energy was developed using the present technique and a physiques correction equation was derived from the relationship between parameters of correction factor and counting efficiencies of the JAERI whole-body counter. The uncertainties in body burdens of Cs-137 estimated with the JAERI whole-body counter were also investigated using the Monte Carlo simulation and measurements. Furthermore, the evaluation method of the peak efficiencies of a Ge semi-conductor detector was developed by the Monte Carlo simulation for optimum arrangement of Ge semi-conductor detectors for designing a precision whole-body counter.

Journal Articles

Study on advancement of ${it in vivo}$ counting using mathematical simulation, in Japanese

Kinase, Sakae

Medical Physics, 30(5), P. 994, 2003/05

A calibration technique for in vivo counting application using Monte Carlo simulation was developed. To validate the calibration technique by calculations, the response functions and counting efficiencies of a whole-body counter installed in JAERI were evaluated using the simulation and measurements. Consequently, the calculations are in good agreement with the measurements. The uncertainties in body burdens of 137Cs estimated with the whole-body counter were also investigated using the Monte Carlo simulation and measurements. It was found that the uncertainties of body burdens estimated with the whole-body counter are strongly dependent on various sources of uncertainty such as radioactivity distribution within the body and counting statistics.

Journal Articles

Comparison of synchrotron radiation calculation between EGS4, FLUKA, PHOTON and STAC8

Asano, Yoshihiro; Liu, J. C.*

KEK Proceedings 2002-18, p.48 - 54, 2003/01

The light energy was not higher than soft X-rays so that the radiation safety for synchrotron radiation passed for unworthy issues of attention. With constructing and operating the third generation facilities such as SPring-8, however, high energy synchrotron radiation of extremely high intense is available, and high accuracy should be required in the shielding and safety design for the beam of synchrotron radiation. Furthermore, the middle size facilities such as CLS (Canadian Light Source) are now under construction and the optimum design of shielding is desired to construct the beamline with safety and compact. It is necessary for the purpose to verify the detailed evaluation technique. Therefore, taking the SPEAR3 bending magnet and BL11-3 wiggler beamlines in the examples, the characteristics of the codes were investigated in comparison with synchrotron radiation shielding design code PHOTON, STAC8 and Monte Carlo simulation code EGS4, FLUKA

Journal Articles

Analyses of absorbed dose to tooth enamel against external photon exposure

Takahashi, Fumiaki; Yamaguchi, Yasuhiro; Iwasaki, Midori*; Miyazawa, Chuzo*; Hamada, Tatsuji*; Funabiki, Jun*; Saito, Kimiaki

Radiation Protection Dosimetry, 103(2), p.125 - 130, 2003/01

 Times Cited Count:4 Percentile:32.68(Environmental Sciences)

Absorbed dose to tooth enamels against external photon exposure was examined by the Electron Spin Resonance (ESR) dosimetry using tooth samples placed in a realistic physical phantom. Dose to teeth region was also measured with thermo-luminescence dosimeters (TLDs). A voxel-type phantom was constructed from CT images of the physical phantom. Monte Carlo calculations with this voxel-type phantom were performed to analyse the results of the experiments. The obtained data in this study were compared to the enamel doses, which were calculated with a modified MIRD-type and already given in a previous paper. The results suggested that the conversion factors from enamel dose to organ doses obtained by the modified MIRD-type phantom are to be applicable for retrospective individual dose assessments by the ESR dosimetry. The analysis, however, indicated that the size and figure of the head can affect the enamel dose for low photon energy region below 100keV.

Journal Articles

Conversion from tooth enamel dose to organ doses for ESR dosimetry

Takahashi, Fumiaki; Yamaguchi, Yasuhiro

Radiation Risk Assessment Workshop Proceedings, p.71 - 78, 2003/00

Conversion from tooth enamel dose to organ doses against external photon exposure were studied in order to develop a method that can retrospectively estimate organ doses by the Electron Spin Resonance (ESR) dosimetry using tooth samples. Monte Carlo calculations using EGS4 code were performed to obtain dose to tooth enamel and organ doses by using a modified MIRD-type phantom. The Electron Spin Resonance (ESR) dosimetry using tooth samples and dose measurements using thermo-luminescence dosimeters (TLDs) were also carried out to examine dose to teeth region with a realistic physical phantom. A Voxel-type phantom was constructed from CT images of the physical phantom. Monte Carlo calculations with the Voxel-type phantom were performed to verify the results of the experiments and enamel doses calculated by use of the modified MIRD-type phantom. The obtained data are to be useful for the retrospective assessment of individual dose in past exposure events by the ESR dosimetry with tooth enamel.

Journal Articles

An EGS4 user code for designing $$gamma$$ ray detection systems

Oishi, Tetsuya; Tsutsumi, Masahiro; Sugita, Takeshi*; Yoshida, Makoto

Proceedings of 1st Asian and Oceanic Congress for Radiation Protection (AOCRP-1) (CD-ROM), 9 Pages, 2002/10

An EGS4 user code has been developed to design gamma ray detection systems for complex shapes of radioactive sources. The code is fundamentally based on the PRESTA-CG, which is improved on the electron transport in the EGS4 and specialized for using a combinatorial geometry (CG) method. The newly added functions are classified mainly into two parts of the transport of particles and the definition of sources. This user code was applied to some detectors used for low-level radioactive wastes monitoring in order to demonstrate the availability of this code. As the result, it was found that the response of anti-Compton spectrometer and the radiation background in a concrete building could be suitably estimated.

Journal Articles

Conversion from tooth enamel dose to organ doses for the electron spin resonance dosimetry

Takahashi, Fumiaki; Yamaguchi, Yasuhiro; Iwasaki, Midori*; Miyazawa, Chuzo*; Hamada, Tatsuji*; Saito, Kimiaki

Journal of Nuclear Science and Technology, 39(9), p.964 - 971, 2002/09

 Times Cited Count:6 Percentile:41.16(Nuclear Science & Technology)

Conversion from tooth enamel dose to organ doses was analyzed to establish a method of retrospective individual dose assessment against external photon exposure by the Electron Spin Resonance (ESR) dosimetry. Dose to tooth enamel was obtained by Monte Carlo calculations using a modified MIRD-type phantom. The calculated tooth enamel doses were verified by measurements with thermo-luminescence dosimeters inserted in a physical head phantom. Energy and angular dependences of tooth enamel dose were compared with those of other organ doses. Additional Monte Carlo calculations were performed to study the effects of human model on the tooth enamel dose with a voxel-type phantom, which was based on CT images of the physical phantom. The data derived with the modified MIRD-type phantom were applied to convert from tooth enamel dose to organ doses against external photon exposure in a hypothesized field, where scattered radiations were taken into account. The results indicated that energy distribution of photons incident to a human body should be required to evaluate precisely individual dose by the ESR dosimetry using teeth.

Journal Articles

Analysis of absorbed dose to tooth enamel for ESR dosimetry

Takahashi, Fumiaki; Yamaguchi, Yasuhiro; Saito, Kimiaki; Iwasaki, Midori*; Miyazawa, Chuzo*; Hamada, Tatsuji*; Funabiki, Jun*

Journal of Nuclear Science and Technology, 39(Suppl.2), p.1314 - 1317, 2002/08

An analysis of dose to tooth enamel was carried out to develop a method that can predict the organdose and effective dose by the Electron Spin Resonance (ESR) dosimetry using teeth for external photon exposure. Absorbed dose to tooth enamel were obtained with Monte Carlo calculations using EGS4 code with a mathematical human model, which has a newly defined teeth-part. Experiments were also carried out to investigate the dose at the tooth area with a physical head phantom. The calculated doses to tooth enamel were, however, less than the measured doses with the TLDs for the case of photon incidence from the back of a human body. Then, a computational human model, called a “Voxel (Volume-pixel) type" phantom was constructed based upon a computed topography (CT) image of the physical head phantom used in the experiments.The additional Monte Carlo calculations were performed to verify the results in the experiments with the EGS4 in conjunction with user's code UCPIXEL and the Voxel type phantom.

Journal Articles

Application of Ge semi-conductor detector to whole-body counter

Kinase, Sakae; Noguchi, Hiroshi; Nakamura, Takashi*

KEK Proceedings 2001-22, p.30 - 36, 2001/12

no abstracts in English

Journal Articles

Relations between tooth enamel dose and organ doses for the Electron Spin Resonance dosimetry against external photon exposure

Takahashi, Fumiaki; Yamaguchi, Yasuhiro; Iwasaki, Midori*; Miyazawa, Chuzo*; Hamada, Tatsuji*

Radiation Protection Dosimetry, 95(2), p.101 - 108, 2001/09

 Times Cited Count:26 Percentile:86.17(Environmental Sciences)

An analysis of doses to tooth enamel and to organs was carried out to develop a method that can predict the organ doses and the effective dose by the Electron Spin Resonance (ESR) dosimetry using tooth samples for external photon exposure. Absorbed dose to tooth enamel and organ doses were obtained by Monte Carlo calculations using EGS4 code in combination with a mathematical human model with a newly defined teeth-part. The calculations gave quantitative relations between tooth enamel dose and organ doses for some cases of external photon exposure. It was also found that tooth enamel dose depends more significantly on energy of incident photons than the other organ dose or the effective dose. The obtained data are to be useful for the assessment of individual dose in past exposure events by the ESR dosimetry with tooth enamel.

62 (Records 1-20 displayed on this page)