• Title/Summary/Keyword: Dosimetry protocol

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Proton Beam Dosimetry Intercomparison

  • Fukumura, Akifumi;Kanai, Tatsuaki;Kanematsu, Nobuyuki;Yusa, Ken;Maruhashi, Akira;Nohtomi, Akihiro;Nishio, Teiji;Shimbo, Munefumi;Akagi, Takashi;Yanou, Toshihiro;Fukuda, Shigekazu;Hasegawa, Takashi;Kusano, Yohsuke;Masuda, Yasutaka
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2002.09a
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    • pp.252-254
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    • 2002
  • A new protocol for dosimetry in external beam radiotherapy is published by the Japan Society of Medical Physics (JSMP) in 2002. The protocol deals with proton and heavy ion beams as well as photon and electron beams, in accordance with IAEA Technical Report Series No. 398. To establish inter-institutional uniformity in proton beam dosimetry, an intercomparison program was carried out with the new protocol. The absorbed doses are measured with different cylindrical ionization chambers in a water phantom at a position of 30-mm residual range for a proton beam, that had range of 155 mm and a spread out Bragg peak (SOBP) of 60-mm width. As a result, the intercomparison showed that the use of the new protocol would improve the +/- 1.0 % (one standard deviation) and 2.7 % (maximum discrepancy) differences in absorbed doses stated by the participating institutions to +/- 0.3% and 0.9 %, respectively. The new protocol will be adopted by all of the participants.

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Thermally assisted IRSL and VSL measurements of display glass from mobile phones for retrospective dosimetry

  • Discher, Michael;Kim, Hyoungtaek;Lee, Jungil
    • Nuclear Engineering and Technology
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    • v.54 no.2
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    • pp.429-436
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    • 2022
  • Investigations of retrospective dosimetry have shown that components of mobile phones are suitable as emergency dosimeters in case of radiological incidents. For physical dosimetry, components can be read out using optically stimulated luminescence (OSL), thermoluminescence (TL) and phototransferred thermoluminescence (PTTL) methods to determine the absorbed dose. This paper deals with a feasibility study of display glass from modern mobile phones that are measured by thermally assisted (Ta) optically stimulated luminescence. Violet (VSL, 405 nm) and infrared (IRSL, 850 nm) LEDs were used for optical stimulation and two protocols (Ta-VSL and Ta-IRSL) were tested. The aim was to systematically investigate the luminescence properties, compare the results to blue stimulated Ta-BSL protocol (458 nm) and to develop a robust measurement protocol for the usage as an emergency dosimeter after an incident with ionizing radiation. First, the native signals were measured to calculate the zero dose signal. Next, the reproducibility and dose response of the luminescence signals were analyzed. Finally, the signal stability was tested after the storage of irradiated samples at room temperature. In general, the developed Ta-IRSL and Ta-VSL protocols indicate usability, however, further research is needed to test the potential of a new protocol for physical retrospective dosimetry.

Fingernail electron paramagnetic resonance dosimetry protocol for localized hand exposure accident

  • Jae Seok Kim;Byeong Ryong Park;Minsu Cho;Won Il Jang;Yong Kyun Kim
    • Nuclear Engineering and Technology
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    • v.55 no.1
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    • pp.270-277
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    • 2023
  • Exposure to ionizing radiation induces free radicals in human nails. These free radicals generate a radiation-induced signal (RIS) in electron paramagnetic resonance (EPR) spectroscopy. Compared with the RIS of tooth enamel samples, that in human nails is more affected by moisture and heat, but has the advantages of being sensitive to radiation and easy to collect. The fingernail as a biological sample is applicable in retrospective dosimetry in cases of localized hand exposure accidents. In this study, the dosimetric characteristics of fingernails were analyzed in fingernail clippings collected from Korean donors. The dose response, fading of radiation-induced and mechanically induced signals, treatment method for evaluation of background signal, minimum detectable dose, and minimum detectable mass were investigated to propose a fingernail-EPR dosimetry protocol. In addition, to validate the practicality of the protocol, blind and field experiments were performed in the laboratory and a non-destructive testing facility. The relative biases in the dose assessment result of the blind and field experiments were 8.43% and 21.68% on average between the reference and reconstructed doses. The results of this study suggest that fingernail-EPR dosimetry can be a useful method for the application of retrospective dosimetry in cases of radiological accidents.

Development of Web-based Dosimetry Calibration Program for High Energy Radiation (웹 기반 고 에너지 방사선에 대한 흡수선량 교정 프로그램 개발)

  • Shin Dong Oh;Shin Dong Ho;Kim Sung Hoon;Park Sung Yong;Seo Won Seop;Ahn Hee Kyung;Kang Jin Oh;Hong Seong Eon
    • Progress in Medical Physics
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    • v.16 no.3
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    • pp.116-124
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    • 2005
  • Absorbed dose dosimetry protocols of high energy photon and electron beams, which are widely used and based on an air kerma calibration factors, have somewhat complex formalism and limitations for improving dosimetric accuracy due to uncertainty of the physical parameters used. Recently the IAEA and the AAPM published the absorbed dose to water-based dosimetry protocol. In this work web-based dose calibration program for IAEA TRS-398 and AAPM TG-51 protocols were developed. This program developed using the Visual C$\#$ language can be used in the internet. User selectable dosimetry protocol on the web allows the absorbed dose to water data of the two protocols at a reference point to be easily compared, and enables to conveniently manage and understand the current status of the dosimetry calibration performed at participating institutions in korea. This program and the resultant database from the web-based calibration can be useful in developing new dosimetry protocols in Korea.

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Medical Application of Radiation Internal Dosimetry (방사선 내부흡수선량의 의학적 적용)

  • Kim, Kyeong-Min;Lim, Sang-Moo
    • Nuclear Medicine and Molecular Imaging
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    • v.42 no.2
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    • pp.164-171
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    • 2008
  • Medical internal radiation dosimetry (MIRD) is an important part of nuclear medicine research field using therapeutic radioisotope. There have been many researches using MIRD for the development of new therapeutic approaches including radiopharmaceutical, clinical protocol, and imaging techniques. Recently, radionuclide therapy has been re-focused as new solution of intractable diseases, through to the advances of previous achievements. In this article, the basic concepts of radiation and internal radiation dosimetry are summarized to help understanding MIRD and its application to clinical application.

Comparison of Air Kerma­based and Absorbed Dose to Water­based Protocols in the Dosimetry of High Energy Electron Beams (고 에너지 전자선에 대한 공기커마와 물 흡수선량에 기반한 프로토콜간의 비교)

  • 박창현;신동오;박성용
    • Progress in Medical Physics
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    • v.14 no.4
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    • pp.249-258
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    • 2003
  • A few years ago, a proposal was made to change the dosimetry from the air kerma-based reference dosimetry to the absorbed dose-based reference dosimetry for all radiotherapy beams of ionizing radiation to improve the accuracy of dosimetry. Here, we present a dosimetry study in which the two most widespread absorbed dose­based protocols (IAEA TRS­398 and AAPM TG­51) were compared with an air kerma­based protocol (IAEA TRS-277) by measuring the absorbed dose in the same reference depth. Measurements were performed in three clinical electron beam energies using a PTW 30002 cylindrical chamber, and Markus and Roos plane­parallel chambers. $^{60}$ Co calibration factors were obtained from the KFDA. The absorbed dose differences between the air kerma­based and absorbed dose­based protocols were within 2.0% for all chambers in all beams. The results thus show that the obtained absolute dose values will be not significantly altered by changing from the air kerma­based dosimetry to the absorbed dose­based dosimetry. It was also shown that absorbed dose values between the absorbed dose­based protocols agreed by deviations of less than 0.5% for a cylindrical chamber and less than 0.7% for plane­parallel chambers using cross­calibration factors. Although the use of a cylindrical chamber and plane­parallel chambers resulted in a difference of less than 2% for all situations investigated here, to reduce errors, the plane­parallel chambers are recommended for electron energies in which the use of cylindrical chamber is not permitted in each protocol.

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Radiation Dosimetry for Radionuclide Therapy (동위원소 치료 관련 방사선 흡수선량평가)

  • Kim, Eun-Hee
    • 대한핵의학회:학술대회논문집
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    • 2001.05a
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    • pp.4-10
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    • 2001
  • The radionuclide therapy is a protocol for tumor control by administering radionuclides as the cytotoxic agents. Radionuclides concentrated at the site of cancerous lesion are expected to kill the cancerous cells with minimal injury to the normal tissue. The efficacy of every radionuclide treatment can be evaluated by examining the toxicity to the lesion differentiated from that to the normal tissue. Radiation dosimetry is the procedure of quantitating the energy absorbed by target volumes of interest. Dosimetric information plays an indicator of the expected radiation damage and thus the therapeutic efficacy. This paper summarizes the dosimetric aspects in radionuclide therapy in terms of radionuclides of use, radiation dosimetry methodology and considerations for each treatment in practical use.

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Determination of TRS-398 Quality Factors for Cs-137 Gamma Rays in Reference Dosimetry (Cs-137 감마선의 선량측정을 위한 TRS-398 선질인자 결정에 관한 연구)

  • Kang, Sang Koo;Rhee, Dong Joo;Kang, Yeong Rok;Kim, Jeung Kee;Jeong, Dong Hyeok
    • Progress in Medical Physics
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    • v.25 no.3
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    • pp.123-127
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    • 2014
  • The Cs-137 irradiator is widely used to irradiate biological samples for radiobiological research. To obtain the accurate outcomes, correct measurements of the delivered absorbed dose to a sample is important. The IAEA protocols such as TRS-277 and TRS-398 were recommended for the Cs-137 reference dosimetry. However in TRS-398 protocol, currently known as the most practical dosimetry protocol, the quality factor ($k_{Q,Q_0}$) for Cs-137 gamma rays is not suggested. Therefore, the use of TRS-398 protocol is currently unavailable for the Cs-137 dosimetry directly. The calculation method previously introduced for high energy photon beams in radiotherapy was used for deriving the Cs-137 beam qualities ($k_{Q,Q_0}$) for the 15 commercially available farmer type ionization chambers in this study. In conclusion, $k_{Q,Q_0}$ values were ranged from 0.998 to 1.002 for Cs-137 gamma rays. These results can be used as the reference and dosimeter calibrations for Cs-137 gamma rays in the future radiobiological researches.

Determination of Quality Factors for Cylindrical Ionization Chambers in kV X-rays: Review of IAEA Dosimetry Protocol and Monte Carlo Calculations and Measurements for N23333 and N30001 Chambers (kV X-선에서 원통형전리함의 선질인자 결정에 관한 연구: IAEA 프로토클 고찰과 N23333, N30001 전리함에 대한 몬테칼로 계산 및 측정)

  • Lee Kang Kyoo;Lim Chunil;Chang Sei Kyung;Moon Sun Rock;Jeong Dong Hyeok
    • Progress in Medical Physics
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    • v.16 no.2
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    • pp.53-61
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    • 2005
  • The quality factors for cylindrical ionization chambers for kV X-rays were determined by Monte Carlo calculation and measurement. In this study, the X-rays of 60-300 kV beam (lSO-4037) installed in KFDA and specified in energy spectra and beam qualities, and the chambers of PTW N23333 and N30001 were investigated. In calculations, the $R_{\mu}\;and\;R_{Q,Q_{0}}$ in IAEA dosimetry protocols were determined from the air kerma and the cavity dose obtained by theoretical and Monte Carlo calculations. It is shown that the N30001 chamber has a flat response of $\pm1.7\%$ in $110\~300kV$ region, while the response range of two chambers were shown to $\pm3\~4\%$ in $80\~250kV$ region. From this work we have discussed dosimetry protocol for the kV X-rays and we have found that the estimation of energy dependency is more important to apply dosimetry protocol for kV X-rays.

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Use of Cylindrical Chambers as Substitutes for Parallel-Plate Chambers in Low-Energy Electron Dosimetry

  • Chun, Minsoo;An, Hyun Joon;Kang, Seong-Hee;Cho, Jin Dong;Park, Jong Min;Kim, Jung-in
    • Progress in Medical Physics
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    • v.29 no.1
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    • pp.16-22
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    • 2018
  • Current dosimetry protocols recommend the use of parallel-plate chambers in electron dosimetry because the electron fluence perturbation can be effectively minimized. However, substitutable methods to calibrate and measure the electron output and energy with the widely used cylindrical chamber should be developed in case a parallel-plate chamber is unavailable. In this study, we measured the correction factors and absolute dose-to-water of electrons with energies of 4, 6, 9, 12, 16, and 20 MeV using Farmer-type and Roos chambers by varying the dose rates according to the AAPM TG-51 protocol. The ion recombination factor and absolute dose were found to be varied across the chamber types, energy, and dose rate, and these phenomena were remarkable at a low energy (4 MeV), which was in good agreement with literature. While the ion recombination factor showed a difference across chamber types of less than 0.4%, the absolute dose differences between them were largest at 4 MeV at approximately 1.5%. We therefore found that the absolute dose with respect to the dose rate was strongly influenced by ion-collection efficiency. Although more rigorous validation with other types of chambers and protocols should be performed, the outcome of the study shows the feasibility of replacing the parallel-plate chamber with the cylindrical chamber in electron dosimetry.