Nagasaki-Chiba-Mainz-Bremen
Radiation Research Initiative

International Symposium on
Radiation Health Effects
and Protection
Medical Radiation Exposure
and Radiation Emergencies
Nagasaki 2015

2nd Mar – 3rd Mar 2015
Pompe Auditorium, Nagasaki University, Japan

Radiation Health Effects due to Nuclear Disasters Lessons
from Chernobyl and Fukushima
Day 1: Monday, 2 March 2015
Introduction and welcome Chairman: Prof. Noboru Takamura
13:00

Opening remarks:
Prof. Yasushi Miyazaki (Vice-Director, Atomic Bomb Disease Institute, Nagasaki University)

13:10

Keynote: Environmental Radiation and Health – What are the Key Issues?
Prof. Hajo Zeeb (Leibniz Institute for Prevention Research and Epidemiology - BIPS)

13:40

Special Lecture: Lessons from Fukushima: The Viewpoint of a Frontline Physician
Prof. Arifumi Hasegawa (Fukushima Medical University)

14:20

The Current Situation of the Internal Radiation Exposure Screening Program in Hama-dori
and the Future Tasks
Dr. Masaharu Tsubokura (Tokyo University)

14:50

Post-Chernobyl Papillary Thyroid Carcinoma in Children and Adolescents of Belarus
Dr. Svetlana Mankovskaya (Institute of Physiology, National Academy of Sciences ofBelarus）

Tea break
Chairman: Prof. Naoki Matsuda
15:20-50
15:50

Relevance and Topicality of Studies of Radiation-Induced and Autoimmune Diseases in the
Republic of Belarus during the Late Post-Chernobyl Period
Prof. Vasili Roudenok (Belarusian State Medical University)

16:30

Major Health Parameters among Children of Gomel Region after the Chernobyl
CatastropheProf. Alexandr Kozlovsky (Gomel State Medical University)

Young Researchers Session (each 20 min)Chairman: Dr. Keiichi Akahane
17:10

Evaluation of current internal Cs-137 exposure in residents living around the Chernobyl
Nuclear Power Plant
Dr. Yuko Kimura (Atomic Bomb Disease Institute, Nagasaki University)

17:30

Evaluation of the risk perception about health effects of radiation among residents ofFukushima
Dr. Makiko Orita (Atomic Bomb Disease Institute, Nagasaki University)

17:50

Potassium Iodide blockage of the thyroid gland – a systematic review and future work
Dr. Steffen Dreger, Hajo Zeeb (Leibniz Institute for Prevention Research and Epidemiology)
Closing Remarks for Day 1
Prof. Noboru Takamura (Atomic Bomb Disease Institute, Nagasaki University)

Research on Medical Radiation Exposure
from Diagnostic and Therapeutic Procedures
Day 2: Tuesday, 3 March 2015
Introduction and welcome Chairman: Prof. Takashi Kudo
09:00

Opening remarks and Keynote:
Risk of Medical Radiation; Diagnosis, Intervention and Nuclear Medicine.
Prof. Takashi Kudo (Atomic Bomb Disease Institute, Nagasaki University)

09:15

Cardiovascular Disease after Exposure to Ionizing Radiation
Dr. Daniel Wollschläger (Institute of Medical Biostatistics, Epidemiology, and Informatics,
Mainz University Medical Center)

09:45

Methodological limitations of studies on cancer risks in children exposed to computed
topographies and there possible counter-actions.
Dr. Lucian Krille (International Agency for Research on Cancer, Lyon, France)
Dr. Steffen Dreger (Leibniz Institute for Prevention Research and Epidemiology)

10:15

Dose Estimations of Medical Exposures in Japan
Dr. Keiichi Akahane (National Institute for Radiological Science, NIRS)

10:45-11:00

Tea break

Chairman: Prof. Hajo Zeeb
11.00

Special Lecture: Pediatric CT examination in Japan
Dr. Osamu Miyazaki (National Center for Child Health and Development, NCCHD)

Young Researchers Session (each 20 min)Chairman: Dr. Daniel Wollschläger
11:40

Changes in Radiological Imaging Frequencies in Children Before and After the Accident at
the Fukushima Daiichi Nuclear Power Plant in Fukushima Prefecture
Dr. Kouji Yoshida (Fukushima Medical University)

12.00

Biological Consequence of Radiation Exposure at CT
Dr. Wataru Fukumoto (Hiroshima University)

12:20

Thyroid cancer as second cancer after Childhood radiation therapy
Dr. Peter Scholz-Kreisel (Institute of Medical Biostatistics, Epidemiology, and Informatics,
Mainz University Medical Center)

12:40-13:30

Lunch

13.30

Round Table Discussion for Future Study Projects.

14:30

Closing Remarks for Day 2 and the Symposium
Prof. Takashi Kudo (Atomic Bomb Disease Institute, Nagasaki University)

Environmental radiation and health – what are the key issues?
Hajo Zeeb
Leibniz Institute for Prevention Research and Epidemiology – BIPS, Bremen, Germany

The use of ionizing radiation has been a hallmark of modern life over more than a century.
Both the beneficial and the harmful potential of ionizing radiation have been exploredintensely. For the public, the most relevant issues of ionizing radiation are medical uses on the
one side, and environmental as well as, for a smaller part of the public, occupational
exposures and their impact on health. Environmental radiation may derive from natural or
man-made sources: exposures associated with nuclear energy generation and particularly,
with accidents such as Chernobyl and Fukushima, continue to provide extensive ground forscientific research, public debate and dispute. Several core issues can be identified in thiscontext: a) improving radiation science for better understanding of the range, distribution andintensity of situation-specific environmental exposures of the public b) clear characterizationof potential health outcomes linked associated with ionizing radiation particularly in the lowdose range c) appropriate risk communication and dialogue between science and the public
about findings and their meaning d) identifying and select relevant radiation protection
approaches and societal solutions to minimize risks in the future. These issues will be
explored in more detail in the talk, using examples involving real or potential environmental
radiation exposures.

Lessons from Fukushima:
The Viewpoint of a Frontline Physician
Arifumi Hasegawa
Department of Radiation Disaster Medicine, Fukushima Medical University, Fukushima,Japan
In the initial phase after the accident, we were concerned about widespread occurrenceof injuries and sickness with the heavy contamination and high exposure doses observedin workers at the Fukushima Daichi Nuclear Power Plant (FNPP). However, none ofsuch cases have occurred. One of the fundamental problems was the serious difficulty inmaintaining the medical system in communities around FNPP. There are only three
medical facilities within 20 km of the plant, none of which are full-fledged hospitals,
and two were under the control of the Tokyo Electric Power Company. Anotherproblem was how to improve workers’ awareness about their own health and safety inthe plant. Since the accident, lethal heatstroke and the outbreak of infectious diseases in
the plant has been prevented by labor health initiatives. On the other hand, lethal
injuries from industrial accidents due to the failure to institute simple safe-workprocedures occurred frequently over a short period. Unexpected radiation injury andsickness are still a serious concern at the plant and medical specialists should prepare
carefully for unexpected emergencies.
More than 60 hospital patients and elderly people in nursing facilities died during
evacuation after the accident. We must remember that they did not suffer from radiation
exposure, but died during the evacuation efforts intended to avoid it. Since the accident,
there has been no direct radiation effect on residents and the possibility of radiation
health effects is quite low, according to estimates by the World Health Organization andthe United Nations Scientific Committee on the Effects of Atomic Radiation. However,secondary health effects not directly related to radiation have become an important issue.
Approximately 130,000 evacuees are still living in temporary housing. Long-term
evacuation causes not only disuse syndrome and lifestyle-related diseases, but also
psychological challenges with disruptions in local community solidarity. Moreover,there is a gap in risk perception among residents, which creates difficulties in finding
consensus on the radiation standards defined by the government. Although thegovernment is promoting the return of evacuees to their hometowns by engaging indecontamination efforts to reduce environmental radiation levels and rebuilding theinfrastructure around FNPP, the numbers returning have been lower than expected.
From the viewpoint of a front-line physician, there are thus no direct radiation healtheffects in Fukushima, but indirect influences have become issues of serious concern.

The current situation of the internal radiation exposure
screening program in Hama-dori and the future tasks
Masaharu Tsubokura
University of Tokyo, Minami-soma Municipal General Hospital, Japan.
Since the Fukushima Dai-ichi nuclear power plant disaster on 11 March 2011, a regularinternal radiation exposure-screening program has been in place in Fukushima. From
this, we now know that the level of chronic exposure among the residents has been kept
at a very low level from their current daily practices. The results from the foodinspection programmes and a whole body counter test for infants (Babyscan) also
showed the similar results.
However, the level of awareness and the feeling of anxiety the residents experience
about the current situation vary by individuals. When the number of residents who are
no longer interested in radiation and avoid discussing about it increases, people who
avoid to consume locally produced food products also exist, especially among theyoung generation. Within Minami-soma city, close to 70-80 % of parents with smallchildren have answered that they intentionally avoid eating locally produced foodproducts. Many of them are also worried about water safety. When the number ofindividuals who attend an information seminar or study session is decreasing, there is astrong opposition against using locally produced rice. Furthermore, many students arecontinuing to feel worried about their future especially about their health, pregnancy
and delivery.
There are various causes to the current trend such as the distrust relationship between
farmersandconsumers,
issuesassociatedwithcompensations
andradiation-contamination levels, and the cultural differences. While education and risk
communication could be one of the solutions to the current complexity in Fukushima, it
is in the process of trial and error. The education on radiation and health is not merely
about reducing the overall radiation level, but it is also a part of the public education
aiming for children to regain their self-esteem and avoid isolation. Similarly, theinterventions in place after the disaster including the internal radiation
screening-program are not just for measuring and reducing the levels of exposure. It isalso important for maintaining the individual’s dignity, and for protecting the regional
culture and history.
In this session, I would like to discuss about the current local situation in the context ofradiation issues and other public health problems that have arisen after the incident, andthe direction in which we much move forward.

Post-Chernobyl papillary thyroid carcinoma in children andadolescents of Belarus
Svetlana Mankovskaya1,2, Mikhail Fridman1,2, Olga Krasko4, Yuri Demidchik2, 3.
1
Institute of Physiology, National Academy of Sciences of Belarus
2
Republic Centre for Thyroid Tumors, Minsk, Belarus;
3
Belarusian Medical Academy of Post-Graduate Education, Minsk, Belarus;
4
United Institute of Informatics Problems, National Academy of Sciences of Belarus.
mankovskaya.svetlana@gmail.com
This is a retrospective analysis of clinical and histological characteristics of papillary
thyroid carcinoma (PTC) that have arisen in the Belarusian childhood population exposedto the radioactive fallout from the Chernobyl accident. 936 children and adolescents (600
girls and 336 boys; 1.8:1; 3-18 years old) with PTC who were surgically treated during
the years 1990 through 2005 were investigated. Three subgroups were evaluated: ≤10years old (I subgroup; n=157; 16.8%), 11 to 14 years old (II subgroup; n=364; 38.9%)
and 15 to 18 years old (III subgroup; n=415; 44.3%). Patients in I subgroup comparedwith II and III subgroups were more frequently observed with advanced regional (82.8%
vs 72.2% vs 71.8%; P<0.001) and disseminate (21.7% vs 11.5% vs 6.7%; P<0.001)
spreading. Classical and solid variants of PTC (P<0.001) with carcinoma showing
infiltrative growth (P<0.001) and solid and follicular pattern (P<0.001) were predominant
in I subgroup. Furthermore, PTC in I subgroup was characterized by extensive
intratumoral
fibrosis(P<0.006),
blood
vesselinvasion(P<0.014),
peritumoral/intraglandular psammoma body dissemination (P<0.002) and lymphatic
invasion (P<0.001). Intrathyroid extension of PTC (P<0.001), multifocal growth(P<0.037) and comorbidity (P<0.001) were typical for III subgroup. Extrathyroidal
extension (ETE) can be expected in patients with subcapsular/isthmic location tumor(P<0.0001, OR=3.40), size of the tumor nodule >10 mm (P<0.0001, OR=3.78),
infiltrative growth/diffuse sclerosing involvement (P<0.0001, OR=9.48), extensive
intratumoral fibrosis (P<0.0001, OR=2.79), vascular (P=0.0002, OR=2.94) andlymphatic invasion (P=0.0002, OR=3.63). Lymph node disease can be expected inpatients with ETE (P<0.0001, OR=3.07), size of the tumor nodule >10 mm (P<0.0001,
OR=2.94), lymphatic invasion (P<0.0001, OR=23.41) and peritumoral/intraglandular
psammoma bodies’ dissemination (P= 0.0002, OR=2.26). Distant metastasis associatedwith ETE (P=0.0065, OR=2.20), N1b (P<0.0001, OR=6.08), subcapsular/isthmic
location tumor (P=0.0169, OR=2.21), size of the tumor nodule >10 mm (P=0.0005,
OR=3.47), extensive intratumoral fibrosis (P=0.0211, OR=1.77), age 3-10 years(P<0.0001, OR=5.03), age 11-14 years (P=0.0022, OR=2.43).
This research was executed within the framework of the Project B-1910 ISTC.

Relevance and Topicality of Studies of Radiation-Induced
and Autoimmune Diseases in the Republic of Belarus during
the Late Post-Chernobyl Period
Vasili Roudenok, Natalja Mitkovskaja, Natalja Kononchuk, Alexander Procharav,
Aliaksandr Fedulau, Andrei Sokal, Iryna Kraytsova, and Yulia Bondareva
Belarusian State Medical University, Gomel State Medical University, Minsk, Belarus
The studies of radiation-induced diseases have become increasingly topical. Along withthe studies of immune and autoimmune disorders they have special significance for
Belarus during the late post-Chernobyl period. Radiation-induced diseases encompass
damaging effects on the organs and systems that are manifested as both histologicalchanges and clinical symptoms. Radiotherapy for uterine cancer is widely used in Belarus
after surgical operations as an adjunctive method of treatment and it is the main mode oftreatment for malignant inoperable tumors. In both cases cancericidal doses affect not
only tumors but also the surrounding organs and tissues, as well as the blood system,
which results in the development of radiation-induced reactions and complications:cystitis, proctitis, enterocolitis and leucopenia, the percentage of which varies from 40 to
60%. The date show a negative impact of radiation therapy on the risk of cardiovasculardiseases. Radiotherapy causes damage to the pericardium, myocardium, valves,
conductivity system and coronary arteries. Many of the changes are asymptomatic andare diagnosed only by laboratory and instrumental methods. The highest risk of cardiac
changes has been detected in patients aged 45 to 55 years with left localization of breast
cancer and accompanying cardiac or broncho-pulmonary disorders and obesity after
standard radiotherapy with the total dose to the chest area over 40 Gy. The incidence ofautoimmune pathology is increasing. In particular, the incidence of myasthenia has gone
up. Studies have shown alterations in the immune system including the changes inneuropeptide expression in the thymus which modulate the immune response.

The major health indicators among children in Gomel
Region after the Chernobyl Catastrophe
Alexandr Kozlovsky, Tamara Sharshakova, Vladimir Bortnovsky,
Gomel State Medical University, Belarus,
The Chernobyl Disaster, the greatest radiation accident in the world history, happened in1986. The aftermath of the accident has affected a lot of countries, which allows to state
it has a global nature. Belarus, Ukraine and Russia have been affected most of all.
However the comparative burden of the accident consequences was considerably heavier
for Belarus.
The basis of the medical service for citizens affected by the disaster is mass health checkup, ensuring early detection of illnesses and their timely treatment. There are more than
1.4 million people, including more than 212 thousand children, who are under medical
observation in the republic.
Children living in radioactively polluted areas reveal a higher incidence rate incomparison with their contemporaries who do not pass the special medical check-up.
As a result of the iodine radionuclide effect at the early stage of the accident and theinsufficient measures aimed at the protection of the thyroid gland, there has been an
increase in the incidence rate of thyroid cancer in Belarus since 1990. The number ofthyroid cancer cases increased 33.6 times among children and 2.5-7 times among adults
depending on age groups after the Chernobyl Disaster in comparison with the preaccident period. The majority of the thyroid cancer cases are registered in Gomel andBrest regions.
The average annual indices of the leukemia incidence rate among children at the postaccident period stay stable in all the six regions of Belarus. Elderly people have observed
a tendency to detect leukemia more often but it is still impossible to relate this to theradiation factor effect.
The increased levels of the incidence rate, registered during the special medical check-up,
may be connected not only to the effect of radiation and non-radiation factors of theChernobyl disaster but also to the so-called “screening effect”. To find out the role of theradiation factor in the changes of health state of the people affected by the accident, weneed to conduct long-term radiation and epidemiologic investigations, some of which are
already being realized in Belarus in the framework of national and international programs.

Evaluation of current internal Cs-137 exposure in residents
living around the Chernobyl Nuclear Power Plant
Yuko Kimura1, Jumpei Takahashi3, Oleksandr Gutevich4, Serghii Chornyi4, Naomi
Hayashida2 and Noboru Takamura1
1
Department of Global Health, Medicine and Welfare and 2Division of Strategic
Collaborative Research, Atomic Bomb Disease Institute, Nagasaki University, Japan
3
Center for International Collaborative Research, Nagasaki University, Nagasaki, Japan
4
Zhitomir Inter-Area Medical Diagnostic Center, Korosten, Ukraine
The Chernobyl nuclear power plant (CNPP) accident left large areas contaminated byradionuclides including Cesium-137 (Cs-137). After the accident, the residents living
around CNPP were revealed to have been exposed to Cs-137 through the intake ofcontaminated foods they harvested in kitchen gardens and by consumption of wildmushrooms, resulting in internal exposure. In this study, we evaluated the current
situation of internal Cs-137 exposure in residents living around CNPP and thecontribution of contamination levels of Cs-137 in the soil to this internal exposure in the
Zhitomir region, Ukraine. We selected 10 districts from this region that contained alarge number of inhabitants who had undergone screening for their Cs-137 body burden
by whole body counter (WBC) at the Zhitomir Inter-Regional Diagnostic Center
between 2009 and 2012. We used the classification of Cs-137 soil contamination levels
to classify these 10 districts into 3 groups (group1: 555–1480 kBq/m2; group2:
185–555kBq/m2; group3: 37–185kBq/m2), and collected soil samples from three family
farms and wild forests. The samples were analyzed for 80,000 seconds using a highpurity germanium detector coupled to a multi-channel analyzer. The total number ofparticipants was 36,862 (11,458 females and 25,404 males). The annual effective dose
was below 0.1mSv per year in 94% of the participants. The median Cs-137 body burdenof each sex was below the detectable level, but the concentration of Cs-137 wassignificantly higher in males than in females (p=0.025). A significantly higher Cs-137
body burden was observed in the more contaminated area groups. A relative, but notstatistically significant, relationship was noted between the number of inhabitants who
had detectable Cs-137 determined by WBC and the Cs-137 concentrations of family
farm soils in the area. In conclusion, the Cs-137 body burden was higher in the
population living in more heavily contaminated areas. The internal exposure doses werelimited, but the consumption of locally produced foods was closely related with theinternal exposure of inhabitants around Chernobyl.

Evaluation of the risk perception about health effects ofradiation among residents of Fukushima
Makiko Orita, Naomi Hayashida, and Noboru Takamura
Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
Since the accident at the Fukushima Daiichi Nuclear Power Plant (FNPP) on March 2011,
various research institutions have reported measurements of external and internalradiation exposures among residents in Fukushima Prefecture, suggesting that external
and internal radiation doses caused by the FNPP accident itself were relatively limited.
Nevertheless, the health effects of radiation exposure remain a serious public concern inthe area. It is thus important to evaluate the risk perception of the health effects ofradiation on residents in order to implement comprehensive risk communication. In thisstudy, we conducted a survey in the village of Kawauchi, which was the first to declarethat it was safe for residents to return to their homes. To clarify the factors associated withresidents’ risk perception of radiation exposure and health effects, we asked residents ofthe village to answer a questionnaire; 285 residents (141 men and 144 women) who
completed the questionnaire were included in the analysis.
In terms of results, 85 residents (29.8%) answered that acute radiation syndrome mightdevelop in residents after the accident at FNPP, 154 (54.0%) residents answered that they
had anxieties about the health effects of radiation on children, and 140 (49.1 %) answeredthat they had anxieties about the health effects of radiation on fetal development.
Furthermore, 107 (37.5 %) residents answered that they had anxiety about health effects
that would appear in the general population simply by living in an environment with a
0.23 µSv per hour ambient dose for one year, 149 (52.2 %) reported that they werereluctant to eat locally produced foods like rice or vegetables, and 164 (57.5 %) believedthat adverse health effects would occur in the general population by eating 100 Bq per kg
of mushrooms for one year. The present study showed that the bipolar risk perception
about radiation’s health effects among residents could have a major impact on social wellbeing after the accident at FNPP. Specialists have a responsibility to ensure constant andcomprehensive risk communication with the public.

Potassium Iodide blockage of the thyroid gland – asystematic review and future work
Steffen Dreger, Hajo Zeeb
Leibniz Institute for Prevention Research and Epidemiology - BIPS, Bremen, Germany
Inhalation or ingestion of I-131 released during a radiological or nuclear accident may
cause thyroid cancer as a consequence, as seen e.g. in the major increase in thyroid
cancer incidence among young children and adolescents after the Chernobyl accident in1986. Potassium iodide thyroid blocking (ITB) is known to reduce the risk ofsubsequent thyroid cancer and its administration in the occurrence of such events is
recommended, for example in the WHO “Guidelines for Iodine Prophylaxis following
Nuclear Accidents” from 1999. Potential adverse effects of ITB, however, have only
been rarely investigated systematically so far, and many questions regarding the timing
and the way of administration of ITB remain unanswered.
This presentation briefly summarizes the results of a review on adverse effects of ITB
based on a systematic literature search in scientific medical databases. The search
resulted in 14 articles relevant to the topic, reporting mostly on surveys, ecological andintervention studies. Only one study from Poland focused on effects (both desired andadverse) of an ITB intervention following the Chernobyl accident. All other studies
reported on iodine administration in a different context. Overall, the studies did notreveal severe adverse reactions to potassium iodide in the general public, but neonates
and babies as well as hypersensitive persons require special consideration.
The WHO recommendations now require a revision, and some new evidence regarding
issues such as the age groups for whom ITB should be recommended needs to beincorporated. Thus, the current systematic review will need to be extended and updated
as a basis for the revised version of the WHO guideline. If available, scientific findings
from ITB use after the Fukushima accident will be included.

Cardiovascular disease after exposure to ionizing radiation
Daniel Wollschläger, Hiltrud Merzenich, Maria Blettner
Institute for Medical Biostatistics, Epidemiology and Informatics (IMBEI)
University Medical Center Mainz, Germany
Circulatory diseases are common in Western populations and among the leading causesof death. Exposure to ionizing radiation is a known risk factor as it can damage the heartand blood vessels. In studying these effects, low-dose exposure below 1Gy is typicallyanalyzed separately from high-dose exposure. For the cardiovascular impact of mostly
low-dose exposure, the LSS A-bomb survivors study is an important source of
information, as are the Mayak and WISMUT cohorts. In contrast, high-dose exposure
almost exclusively results from radiotherapy in cancer treatment.
In two studies, IMBEI Mainz is investigating the impact of high-dose radiation
exposure on cardiovascular health: The CVSS study examines a German cohort of 1000
survivors of childhood cancer with radiotherapy treatment. In addition to clinicaltreatment records, CVSS takes into account genetic data, as well as results from acomprehensive cardiovascular medical checkup currently underway with about 600
persons examined. Due to the high response rate, the final results expected at the end of2015 promise reliable information for risk factors as well as for clinical parameters.
The PASSOS study analyzes data from 12500 German women treated with radiotherapy
after breast cancer during 1998-2008. Along with clinical hospital records, we
ascertained information on mortality and cause of death until 2013. To investigate
morbidity endpoints, survivors have been recently sent a questionnaire on
cardiovascular events after cancer therapy. The questionnaire also includes lifestylevariables as potentially confounding risk factors. We will present first results from theindividual dosimetry that was performed for a sample of the patients, allowing us tocharacterize the dose distribution in various functional heart structures.

Methodological limitations of studies on cancer risks inchildren exposed to computed topographies and there
possible counter-actions.
Lucian Krille1, Steffen Dreger2, Hajo Zeeb2
1
International Agency for Research on Cancer, Lyon, France
2
Leibniz Institute for Prevention Research and Epidemiology - BIPS, Bremen, Germany
Computed topography (CT) is an important and indispensable tool in modern medicine.
Besides many advantages it exposes the patient to comparatively high doses of ionizing
radiation, a known carcinogen. In 2001 Brenner estimated that especially children may
be at increased risk of cancer after exposure to CTs. Between 2012 and 2015 the resultsof five cohort studies from UK, Australia, Taiwan, France and Germany were published.
All showed increased cancer risk, albeit the magnitude and the interpretations deviated:
The first two studies were the biggest in terms of size. However they missed information
on cancer predisposing syndromes (PF) which may have led to an overestimation of therisks, depending on the prevalence of the PF. Furthermore no information on theindications of the scans was available, thus leaving room for the possibility of reverse
causation (including cancer-diagnoses related CTs as possible cause for a later occurring
cancer). The two last, rather small studies provided different approaches to access thesesources of overestimation with slightly different conclusions. Their comparability andapplicability in larger pooling studies is still not solved.
All studies so far miss a comprehensive dosimetry, which may distort the risk estimatedper unit dose. Precise dose estimation with exposures dating back 30 years have to copewith missing values and uncertainties. However the novel two-dimensional-Monte- Carloapproach may be used in larger pooling studies to assess and reduce the uncertainty inorder to obtain more precise risk estimates per unit dose.

Dose Estimations of Medical Exposures in Japan
Keiichi Akahane
Medical Exposure Research Project, National Institute of Radiological Sciences, Chiba,Japan
For radiological protection of medical exposures, the frequency and dose data ofradiological procedures should be obtained as well as organ doses for risk estimations.
The data can also be the basis for diagnostic reference levels (DRLs) in radiologicaldiagnoses. In recent, the data collecting system on medical exposures by using software,
which can collect the X-ray CT examination data from DICOM automatically, has beendeveloped in National Institute of Radiological Sciences (NIRS), and been begun to use
collaborating with several medical facilities. The data will be accumulated into the
database of medical exposures in NIRS. As a tool of estimating organ doses in X-ray CT
examinations, the specialists of Oita University of Nursing and Health Sciences and Japan
Atomic Energy Agency (JAEA) have developed WAZA-ARI. It has been in trial
operation in NIRS web server. On 30 January 2015, WAZA-ARI v2 was opened to the
public as the revised new version of WAZA-ARI. The organ doses of 18 body types ofpatients including children can be calculated by using WAZA-ARI v2. It also has the
database function, and output the statistics of X-ray CT examinations inputted by theregistered users. As the hub in the field of medical radiation, Japan Network for Researchand Information on Medical Exposures (J-RIME) has established in 2010. From last year,
a working group of J-RIME for establishing DRLs has started its activities, and all-Japan
DRLs are expected to be established and opened. The database of NIRS would be usefulfor revising DRLs in the future.

Pediatric CT examination in Japan: How to reduce theradiation dose in daily practice.
Osamu Miyazaki
Department of Radiology, National Center for Child Health and Development, Tokyo,
Japan
1. Determine if the ordered CT is justified by the clinical indication
The use of pediatric CT examinations decreased significantly in Japan in the three years
after the Fukushima Daiichi nuclear power plant disaster. This finding may reflect theconcerns of the medical community, the general population, or both. Independent of thedisaster, one children’s hospital showed a marked decrease in CT scans owing to acontinuous in-house campaign to decrease non-essential CT examinations. Thisobservation suggests that arranging a conference for clinicians on radiation protection
for children can be a first step in educating referring physicians.
The use of publicly available appropriateness criteria (ACR [U.S.A], RCR [UK] anddomestic guidelines in Japan) provides a standard way of justifying this approach.
2. Optimize pediatric examination parameters
The mAs (milliampere second) should be adjusted in response to the patient’s physicaldimension and the required mAs is also dependent on the specific imaging task. The
mAs reduction factors for the pediatric abdomen and thorax are available on the Image
Gently website; these have just been republished following last December’s update.
Diagnostic reference levels (DRLs) are thought to be a useful tool for optimization.
The JSRT Scientific Research Group has finished its study of pediatric CT dosing and
DRLs for Japan will be available in April 2015.
Limiting the length of the scout views and the scan length of the clinical images is justas important as limiting the radiation dose to the patient. The extent of the scout views
and the scan should be limited to the area of concern.
Performing both unenhanced and contrast-enhanced abdominal CT can result in twice
the radiation dose per child. Single-phase scans are usually all that is necessary inchildren. Unenhanced and delayed enhanced images rarely provide additional
information and should be performed infrequently unless there are specific indications.

Changes in Radiological Imaging Frequencies in Children
Before and After the Accident at the Fukushima Daiichi
Nuclear Power Plant in Fukushima Prefecture, Japan
Koji Yoshida1,2, Atsushi Kumagai1, Akira Ohtsuru1, Naomi Hayashida2, Takashi Kudo2,
Shunichi Yamashita2, Noboru Takamura2
1
Education Center for Disaster Medicine, Fukushima Medical University, Fukushima,
Japan
2
Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, JapanThe accident at the Fukushima Daiichi Nuclear Power Plant has raised concerns about
radiation exposure, including medical radiation exposure such as x-rays and CT scans,in residents of Fukushima. In this study, we investigated the changes in the numbers ofradiological examinations before and after the accident. We collected data onradiological examinations (e.g., x-rays, CT scans, MRI scans, etc.) from April 1, 2008 to
March 31, 2013 in outpatients who visited Fukushima Medical University Hospital(Fukushima, Japan), and compared the numbers and the types of examinations between
outpatients who underwent examinations before (2008 to 2010) and after (2011 to 2013)
the accident. The number and ratio of outpatients less than 10 years old decreased after
the accident. The number and ratio of x-ray examinations in outpatients less than 10
years old significantly decreased after the accident. The number and ratio of CT
examinations in outpatients less than 10 years old also decreased after the accident. Our
results suggested that the numbers of children decreased after the accident in Fukushima
due to anxiety about radiation exposure to children and their parents. We should
continue to communicate with patients and their families to ensure that they understandthe risks and benefits of radiological imaging in order to overcome their concerns about
the nuclear disaster and to re-establish the medical system in Fukushima.

Biological Consequence of Radiation Exposure at CT
Fukumoto Wataru1, Tashiro Satoshi2, Kajiwara Kenji1,Kaichi Yoko1, Honda Yukiko1
Awai Kazuo1
1

Department of Diagnostic Radiology, Hiroshima University
Department of Cellular Biology, Research Institute for Radiation Biology andMedicine, Hiroshima University
2

Objective:
DNA double-strand breaks (DSBs) are considered as the most significant DNA damages
induced by ionizing radiation. The purpose of this study was to assess DSBs induced byradiation exposure from coronary CT.
Material and Methods:
After institutional review board approval and written informed patient consent wereobtained, 20 patients who had arrhythmia underwent coronary CT before ablation
therapy. Blood sample were obtained before and 15 minutes after CT and DSBs wereanalyzed in lymphocytes using chromosome aberrations and γ-H2AX which werebiomarkers of DSBs.
Results:
Chromosome aberrations in blood lymphocytes before and after CT were 5.3×10-3/celland 7.4×10-3/cell, respectively. γ-H2AX before and after CT were 1.12 and 1.80
foci/cell, respectively. Both biomarkers of DSBs were significantly increased after CT(p = 0.002, 0.001).
Conclusion:
A significant increase of DSBs was obtained after coronary CT.

Thyroid cancer as second cancer after Childhood radiation
therapyPeter Scholz-Kreisel, Hiltrud Merzenich, Maria Brettner
Institute for Medical Biostatistics, Epidemiology and Informatics (IMBEI), Johannes
Gutenberg University Mainz
Radiation therapy is proven highly effective on curing cancer. Nevertheless, ionizing
radiation is associated with a range of late adverse effects including cardiovasculardisease, fertility problems, depression and developing second cancer. The Thyroid glandis highly radiation sensitive. Kaatsch and colleagues showed that 8% of all second
cancer were thyroid cancers.
Gul and colleagues show an exposure of 6 - 40 Gy to the thyroid by scattered radiation,
depending on the localization of the primary neoplasm. Veiga et al reported an exposureof 10 Gy to the Thyroid is associate with a relative risk for thyroid cancer of 13.7
showing a linear rise to a dose of 20 Gy with a decline of risk at higher doses. The
preferred ICRP model as published in BER VII is an exponential model with an
ERR/Gy = 0.79 exp [– 0.083 (e – 30) and no decline at higher doses. However, there is
still much uncertainty in modelling the dose-response curve.
At the Institut for Medical Biostatistics, Epidemiology and informatics (IMBEI) and theGerman childhood Cancer Registry (GCCR) we are currently performing further
investigation to better understand the radiation induced thyroid risk. First, we performeda nested case-control-study, Cohort members are all children with cancer before age 15
reported to the GCCR between 1980 and 2002. Cases are all patients with a second
thyroid cancer; controls are patients with no second cancer at least until the age ofdiagnostic of the corresponding case, matched by age at diagnosis for the first cancer,
gender and date of diagnosis. Second, we perform a systematic literature review and ameta-analysis and to estimate dose-response curve after radiation therapy.
The presentation will summarize the actual knowledge on radiation induced second
thyroid cancer including the results of our case-control study and discuss the different
models and concepts on this topic.

Atomic Bomb Disease Institute,
Nagasaki University