Radiation Environment and Medicine (REM)

REM » Archives » REM Vol.4, No.1

Radiation Emergency Medicine Vol.4, No.1

  • Publisher : Hirosaki University Press
  • Language : English
  • ISSN : 2186-8026 (PRINT)
  • Release : February 2015
  • Issue : Hirosaki University Press
  • pp. 1-64

Articles

Special Contribution

Basic Epidemiology
Methods and Their Application to Epidemiology on Cancer and Radiation (3)

  • Suminori Akiba 

  • Department of Epidemiology and Preventive Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Japan
    Radiat Emerg Med (2015) 4 (1): 1-6

Special Contribution

Principles of Radiation Epidemiology

  • Michaela Kreuzer 

  • Federal Office for Radiation Protection, Department Radiation Protection and Health, Unit Radiation Epidemiology and Radiation Risk,Germany 
    Radiat Emerg Med (2015) 4 (1): 7-10

Abstract

Epidemiology is the study of the distribution and determinants of diseases or other healthrelated events. Descriptive epidemiology aims to investigate the distribution of diseases by time, region or in different groups of individuals, while analytical studies are used to study determinants of diseases. The most common analytical approaches are case-control studies and cohort studies. Both study designs are introduced with respect to methods, measures of risk, weaknesses and strengths. Examples for radiation epidemiological studies are the atomic bomb survivors of Hiroshima and Nagasaki, and occupationally, environmentally or medically radiation exposed populations. Generally, the choice of the study design depends on many factors such as the disease (frequency, latency) and the exposure (rare or not) to be studied, the time over which the study can be carried out, the resources available to collect detailed individual data and the potential to minimize bias and confounding. The interpretation of results of epidemiological studies requires consideration of systematic errors (information bias, selection bias), confounding and chance. Finally, the likelihood that an association between radiation exposure and health outcome is causal should be evaluated. Criteria for assessing if an association is causal include temporal relationship, biological plausibility, consistency, strength of the association, exposure-response relationship, reversibility and coherence.

Special Contribution

Issues and Challenges of Radiation Risk Communication to the Public

  • Jing Chen

  • Radiation Protection Bureau, Health Canada, Canada 
    Radiat Emerg Med (2015) 4 (1): 11-15

Abstract

This article focuses on issues and associated challenges in radiation risk communication to the public. All of the issues start with very simple questions and the challenges are to answer them in a way that can be easily understood by the public. Two of the most commonly asked questions are addressed, “what is radiation?” and “are we safe?”. The discussion is based mostly on information available on the internet to the public. Collectively, more is known and understood about the biological effects of radiation than any other toxin or carcinogen. As health physicists, we are confident that current radiation dose limits protect workers and the public. It is our duty to engage the public, address their concerns, translate our knowledge to their language, and eventually build trust among us. From the discussion given here, one can see that radiation risk communication to the public is a science-based art. Depending on how it is designed, the communication can be a beauty to people when it makes their life easier, or it can turn into a beast when it makes people even more scared of radiation.

Review

Automatic Dicentric Scoring a Real Option to Be Used in Biological Dosimetry

  • Aurélie Vaurijoux1∗, Gaetan Gruel1, Eric Gregoire1, Sandrine Roch-Lefevre1, Pascale Voisin1,
    Cécile Martin1, Philippe Voisin1, Laurence Roy1, and Joan-Francesc Barquinero1, 2

  • 1Institut de Radioprotection et de Sureté Nucléaire (IRSN),Laboratoire de Dosimétrie Biologique (PRP-HOM/SRBE/LDB), France
    2Universtitat Autónoma de Barcelona, Facultat de Biociéncies, Spain 
    Radiat Emerg Med (2015) 4 (1): 16-21

Abstract

In case of a radiological emergency, it is essential to assess the possible dose received by possible victims. Several disciplines, such as physical dosimetry, dose reconstruction and biological dosimetry should put together their expertise to respond as fast as possible. Among different methods used in biological dosimetry, “dicentric analysis” is still the most widely used method, as it has the lowest detection limit, is the one that most accurately estimates the dose, and distinguishes between whole- and partial-body irradiations. To score dicentric chromosomes, peripheral blood lymphocytes have to be stimulated to enter the cell cycle and reach metaphase. In addition, skilled scorers should analyze at the microscope complete cells containing 46 centromeres and to recognize dicentrics chromosomes with their corresponding acentric fragment. For this reason, dicentric analysis is time consuming and in case of an accident involving a large number of victims, it should not be possible to respond promptly. One promising improvement of the methodology is to automate dicentric analysis, and nowadays several laboratories of biological dosimetry have the equipment needed to perform automatic dicentric scoring (ADS). Here we present a review of different experiences carried out at the “Institut de Radioprotection et Surete Nucleaire” from France to compare ADS in relation to manual scoring (MS) and evaluate the feasibility to introduce ADS as a real option to be used instead of MS. The experience obtained indicates that automatic dicentric scoring is a real alternative and is mature enough to substitute manual scoring.

Review

Rapid Test Method of Radio-iodine Radioactivity in Foods/foodstuffs

  • Takahiro Yamada

  • Japan Radioisotope Association, Japan 
    Radiat Emerg Med (2015) 4 (1): 22-26

Abstract

Rapid test of radioactivity contamination in foods/foodstuffs is required to ensure the radiological protection of the public in emergency situation. Just after the Fukushima accident rapid screening of radio-iodine radioactivity in foods/foodstuffs was carried out through over the country. In the present paper, the rapid test method based on the Ministry of Health, Labour and Welfare manual for radioactivity measurements in emergency, which were specified as the normative references for radioactivity monitoring of foods/foodstuffs by testing laboratories, is shown with some considerations for the expected future improvement.

Regular Article

Characteristics of the Environmental Radon and Thoron in Minamidaito-jima, a Comparatively High Background Radiation Island in Japan

  • Yoshitaka Shiroma1∗, Masahiro Hosoda2, Tetsuo Ishikawa3
    Sarata Kumar Sahoo4, Shinji Tokonami5 and Masahide Furukawa6

  • 1Graduate School of Engineering and Sciences, University of the Ryukyus, Japan
    2Hirosaki University Graduate School of Health Sciences, Japan 
    3School of Medicine, Fukushima Medical University, Japan
    4National Institute of Radiological Sciences, Japan 
    5Institute of Radiation Emergency Medicine, Hirosaki University, Japan
    6Faculty of Science, University of the Ryukyus, Japan 
    Radiat Emerg Med (2015) 4 (1): 27-33

Abstract

General survey for the environmental radon and thoron has been performed in Minamidaitojima, Okinawa prefecture, southwestern part of Japan. In situ measurements of the radon and thoron exhalation rates were conducted at a total of 7 points using an accumulation technique with a ZnS(Ag) scintillation detector. The medians of radon and thoron exhalation rates were estimated to be 31 mBq m-2 s-1 and 3,970 mBq m-2 s-1, respectively. The atmospheric radon concentrations were measured at 2 points with an ionization chamber, and the maximum concentration was estimated to be 94 Bq m-3. For the surface soil samples collected at the measurement points of the exhalation rates, arithmetic means for 238U and 232Th series concentration were estimated to be approximately 145 Bq kg-1 dry and 101 Bq kg-1 dry, respectively. These results indicated that the environmental radon and thoron levels in Minamidaito-jima are fairly higher than those of the average of Japan. And it is strongly suggested that the exhalation rates and the concentrations are enhanced mainly due to the surface soil with the relatively high radioactivity.

Regular Article

A Method for Reducing Skin Dose under IVR Pulsed Fluoroscopic X-ray Irradiation

  • Kohsei Kudo1∗, Minoru Osanai1, Junichi Hirota1, Sachio Sato2, Satoshi Naraki2,Katumasa Suzaki2, Akira Fujimori2, Yoshihiro Takai2, 3 and Yoichiro Hosokawa1

  • 1Hirosaki University Graduate School of Health Sciences, Japan 
    2Department of Radiology, Hirosaki University School of Medicine and Hospital, Japan 
    3Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, Japan 
    Radiat Emerg Med (2015) 4 (1): 34-39

Abstract

Interventional radiology (IVR) procedures are indispensable in treatment directly connected to lifesaving. As IVR requires X-ray irradiation for a long time and is carried out repeatedly, the skin dose to the patient is high. We measured waveforms of the entrance surface dose in pulsed fluoroscopy with the intent of reducing the exposure dose from IVR. Using a flat-panel detector (FPD) system, we also measured entrance surface doses in various cases in normaland low-dose modes. As a result, wavetail cutoff of waveforms was confirmed. In addition, we confirmed that in each of the cases of lower pulse rates, lower frame rates, larger FPD sizes, larger irradiation fields, shorter table-FPD distances, and thinner phantom thicknesses,doses decreased. Based on these results, from the perspective of reducing exposure doses, fluoroscopy or exposure should be undertaken using: a low pulse rate; a low frame rate during exposure; a large FPD size without magnification; an irradiation field that is not small; and an FPD brought to close to the patient.

Regular Article

Promoted Instability in an X-ray Irradiated Chromosome Transferred into Werner Syndrome Cells

  • Kentaro Ariyoshi1∗, Keiji Suzuki2, Masami Watanabe3, and Seiji Kodama4

  • 1Hirosaki University Research Institute of Radiation Emergency Medicine, Japan. 
    2Graduate School of Biomedical Science, Nagasaki University, Japan 
    3Radiation Biology Center, Kyoto University, Japan 
    4Laboratory of Radiation Biology, Department of Biological Science, Graduate School of Science, Osaka Prefecture University, Japan 
    Radiat Emerg Med (2015) 4 (1): 40-46

Abstract

Ionizing radiation is a potent genotoxic agent that can induce delayed biological effects referred to as genomic instability. Delayed chromosomal instability has been studied as a typical phenotype of genomic instability in the progeny of irradiated cells, but the mechanisms by which it arises remain obscure. The previous chromosome transfer study revealed that chromosomal instability could be transmitted to the progeny of unirradiated recipient cells by a chromosome exposed to ionizing radiation1). To determine whether the transmitted chromosomal instability is promoted in cells with compromised genomic integrity, we examined chromosome transfer to the cells which have defect of DNA repair genes, such as ataxia telangiectasia mutated gene (ATM), Nijmegen breakage syndrome protein 1 gene (NBS1) and Werner syndrome (WRN) gene. Unfortunately, we could not get clone of ATM or NBS1 deficient cells but we could get Werner syndrome cell line (WS780: WRNmut) which carries transferred chromosome 9. The results indicated that both unirradiated and irradiated chromosomes 9 were stable after chromosome transfer in microcell hybrids derived from non-WS control cells (GM638: WRNwt). In contrast, although all six WRNmutderived microcell hybrids had no rearrangements in the transferred-unirradiated chromosome 9, 11-28% of cells showed the rearranged chromosome 9 in three out of seven WRNmut-derived microcell hybrids transferred with the 6 Gy-irradiated chromosome 9. Thus, the present study demonstrates the possibility that chromosome instability mediated by an irradiated chromosome is promoted in WS cells that harbor multiple defects of genomic integrity.

Note

Analysis Using an NaI(Tl) Detector for Radioactive Materials When Dismantling a Linear Accelerator

  • Shingo Terashima1, Naoki kimura2, Morio Seino2, Mamoru Kubota1,
    Hidetoshi Saito3 and Yoichiro Hosokawa1∗

  • 1Department of Radiological Life Sciences, Division of Medical Life Sciences, Hirosaki University Graduate School of Health Sciences, Japan 
    2Division of Radiology, Hirosaki University Hospital, Japan 
    3Graduate School of Human Health Sciences, Tokyo Metropolitan University, Japan 
    Radiat Emerg Med (2015) 4 (1): 47-52

Abstract

Radioactive materials are produced when a linear accelerator (LINAC) generating highenergy X rays is operated. The following two methods are followed for disposing of these materials in Japan: 1) consigning disposal of the materials to the Radioisotope Association or 2) using a radioactive contaminant confirmation system that allows very-low-dose radioactive contaminants to be disposed of as industrial waste. Identification of radioactive nuclides is required for both methods, and nuclide identification using a high-purity germanium (HPGe) detector is indispensable under the existing circumstances. Upon the disposal of a LINAC in this study, we conducted nuclide analyses using both an HPGe detector and an NaI(Tl) detector, and compared the results. Eleven nuclides were detected in the analysis using the HPGe detector. 51Cr, 54Mn and/or 58Co, 60Co, 65Zn, 124Sb and 198Au could be detected using the NaI(Tl) detector, while 57Co, 110mAg, 181W and 196Au could not be identified with this detector. However, if the count of a spectrum is large and the energy distribution waveforms bore no similarity, nuclides could be identified. The study suggests that an NaI(Tl) detector could be also used for measurement of radioactive materials.

Note

Calculation of Dose Rates and Buildup Factors in Air at 1 m above Ground for 134Cs and 137Cs Sources Having Different Types of Depth Profile

  • Susumu Minato

  • Radiation Earth Science Laboratory, Japan 
    Radiat Emerg Med (2015) 4 (1): 53-56

Abstract

Monte Carlo calculations were carried out to evaluate absorbed dose rates in air and dose buildup factors at a height of 1 m above the air-ground interface for underground 134Cs and 137Cs sources having three typical types of depth profile, i.e. slab, exponential and triangular sources. The calculated results showed that the respective dose rates and buildup factors were relatively different one another. In addition, a linear relationship was found between mean source depths expressed in natural logarithm and the corresponding dose rates.

Note

Radiocesium Inventory on the Campus of Nihon University, Koriyama, Fukushima, Japan

  • Naofumi Akata1,2, Katsuhiko Okuyama3∗, Yuri Tsujimoto3, Natsu Takahashi3, Mai Ishihara3
    Yusuke Arai3, Takaki Itakura3, Takatoshi Sato3, Taiki Ogata3 and Hideki Kakiuchi4

  • 1National Institute for Fusion Science, Japan 
    2The Graduate University for Advanced Studies [SOKENDAI], Japan 
    3Nihon University, Japan 
    4Institute for Environmental Sciences, Japan 
    Radiat Emerg Med (2015) 4 (1): 57-61

Abstract

We have collected surface soil samples on the campus of Nihon University, Koriyama, Fukushima, Japan, after the Fukushima Dai-ichi Nuclear Power Plant accident for three years and measured their radiocesium (134Cs and 137Cs) concentrations to understand the behavior of deposited radiocesium on soil surfaces in the campus. In 2011, the inventory of 134Cs and 137Cs ranged from 73 to 164 kBq m-2 with the arithmetic mean value of 110 ± 33 kBq m-2, and from 83 to 203 kBq m-2 with the arithmetic mean value of 134 ± 42 kBq m-2, respectively. In 2012 and 2013, we found radiocesium inventories were rapidly decreasing at most sampling stations because of university decontamination work programs to remove the surface soil to a depth of 5 cm. Slightly increasing radiocesium inventories were observed at some stations, however, where soil and grass covered soil areas met. We considered that the elevated radiocesium inventories were affected by resuspension of soil dust. The 137Cs residual rate at areas that had not been decontaminated was estimated at approximately 50% during 2012 to 2013.

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