放影研

RERF

Radiation Effects Research Foundation Tours■ Tour times: Free tours (reservations required) are offered from 9:00–16:00 (excluding 12:00–13:00)■ Holidays (tours not available): Saturdays, Sundays, Japanese national holidays, Dec. 29–Jan. 3■ Tour reservations: Contact us in advance by filling out and submitting the “Application for Guided
Tour at RERF” form on our homepage, or by sending the completed form to RERF by fax or as anemail attachment.

Radiation Effects Research Foundation

Dispatch of Lecturers

The Radiation Effects Research Foundation (RERF)
is a Japan-US cooperative research organizationthat conducts studies into the health effects ofatomic-bomb radiation for peaceful purposes.

RERF dispatches lecturers throughout Japan for seminars and meetings to speak on such themes as“Health effects of A-bomb radiation” and “What is radiation?”■ Lecturer requests: Contact us in advance by filling out and submitting the “Lecturer Request Form”
on our homepage, or by sending the completed form to RERF by fax or as an email attachment. (Weask that the party requesting the service bear any associated travel expenses for the lecturer.)

Open HouseRERF has studied the atomic-bomb sur vivors of Hiroshima
and Nagasaki for more than 65 years. Our research results
serve as a primary worldwide scientific basis for determinationof radiation exposure dose limits. We hope to continue
contributing to the health and welfare of theatomic-bomb survivors, for whose cooperation in
RERF studies we are profoundly grateful,and to the enhancement of the healthof all humankind including af fectedindividuals in Fukushima.

RERF holds an Open House event each year.
■ Dates: Typically, the Hiroshima Laboratory holds its Open House on August 5–6, and the Nagasaki
Laboratory on August 8–9. Reservations are not required. (However, please confirm details, such asdates, on the RERF homepage, where Open House information becomes available, about one monthprior to the event.)

Hiroshima Laboratory

Nagasaki Laboratory

5-2 Hijiyama Park, Minami-ku, Hiroshima City,
Japan 732-0815
Tel: 082-261-3131 (switchboard) Fax: 082-261-3297
Email: tour-info@rerf.jp
Homepage: http://www.rerf.jp/

8-6 Nakagawa 1-chome, Nagasaki City,
Japan 850-0013
Tel: 095-823-1121 (switchboard) Fax: 095-825-7202
Email: tour-info-naga@rerf.jp
Homepage: http://www.rerf.jp/

Hir
Sta oshimtion aShukkeien
GardenHiroshima
Museum of Art

Hiroshima
Laboratory

Peace Park
Urakami Cathedral
Nagasaki University
School of Medicine
Atomic Bomb Museum

Matoba-cho
Hiroshima
PrefecturalOffice
Nagasaki Station

Kamiya-cho
A-bomb
Dome
PeaceMemorial Park

Hatchobori

Radiation Effects
Research Foundation

Kokaidomae

Nagasaki
City Hall

Hijiyama-shita
Peace Avenue

TsurumiBridgeKyobashi River

Motoyasu RiverHon RiverHijiyamaPark■ Access
Taxi: 10 minutes from Hiroshima Station / 15
minutes from Hiroshima Peace Memorial Park
Streetcar: From Hiroshima Station, catch the No. 5 streetcar
bound for Ujina, get off at the “Hijiyama-shita”
stop (10 minutes from the Station), and walk 10minutes to the top of the hill.
From Peace Memorial Park, catch a streetcar
bound for Hiroshima Station in front of theA-bomb Dome at the “Genbaku Dome Mae”
stop, and change streetcars at the“Matoba-cho” stop to the No. 5 streetcar
bound for Ujina. Get off at the “Hijiyama-shita”
stop (10 minutes from “Matoba-cho”), andwalk 10 minutes to the top of the hill.

Siebold Memorial MuseumSuwajinjamaeHotarujaya

Hiroshima City
Museum ofContemporary
Art

GloverGarden

34

Radiation Effects
Research Foundation

Oura CatholicChurch■ Access
Taxi: 10 minutes from Nagasaki Station / 25
minutes from Nagasaki Peace Park
Streetcar: From Nagasaki Station, catch the No. 3streetcar bound for Hotarujaya and get off at
the “Hotarujaya” stop, which is that line’s
terminus (15 minutes from the Station).
RERF is located in front of the “Hotarujaya”
stop.

Hiroshima
NagasakiNagasaki
Laboratory

放影研

RERF

Radiation Effects Research Foundation

Late Effects from Radiation

RERF Study Cohorts

Cancer Incidence and Mortality among A-bomb Survivors
Life Span Study (LSS)In UteroStudy

Children of Atomic-bombSurvivors (F1) Study

120,000

3,600

77,000

Clinical Study of the F1
Offspring of A-bomb Survivors

Adult Health Study (AHS)
25,000(1,000)

12,000Adult Health Study
The Adult Health Study is a clinical study of a sub-cohort of the Life Span Study. Examinations of the A-bomb survivor subjects of thestudy are conducted every two years, providing a continuous health profile of this aging population. In addition, blood samples forfuture analysis are collected on the basis of the examinees’ informed consent. This study strives to establish radiation-related risk ofnoncancer diseases and investigate aging- and radiation-related physiological changes. It will be continued throughout the lifetimes ofthe survivors to more accurately grasp radiation’s association and risk in noncancer disease development. The study also provides
useful information for the health management of A-bomb survivors.

In Utero Study
The In Utero Study is designed to examine lifetime health status of about 3,600 persons who were in the womb at the time of bombing.
It is known that, depending on radiation dose, persons exposed at 8–15 weeks of gestation have shown an elevated risk ofmicrocephaly and intellectual impairment. To date, cancer incidence in individuals exposed prenatally tends to increase with radiation
exposure dose at around the same level as incidence in those exposed in childhood (the period 0–5 years). It is considered that many
findings will be obtained by continued follow-up of this in utero study cohort.

Number ofstudy subjects

Study details

Study period①Physical abnormalities at birth

77,000 persons1948–1954②Chromosome aberrations

16,000 persons

1967–1985③Abnormalities in blood protein

24,000 persons

1975–1985④Mortality and cancer incidence

77,000 persons

1946–present⑤Clinical examination oflifestyle diseases

12,000 persons

2002–present

Radiation dose (sievert)

1086

Enlarged

4
20

1.0

1.5

2.0

Distance from hypocenter (km)2.5

Radiation dose (sievert)

Physical Dosimetry

2030

40

50

Years since radiation exposure

Numbers of people dying of leukemia and those contracting
cancer in the Life Span Study cohort
Leukemia(Deaths)(1950-2000)
Cancers(Incidence)(1958-1998)

93/204(46%)

0850/7,851
(11%)

2000

4000

6000

8000(cases)

Radiation Risk (at age of 70)

2
1.5
1.25
1.05
1500

1000

Radiation dose (millisievert)

2000

RERF’s epidemiological research of A-bomb survivors has revealed that exposure toradiation dose of 1 Sv (1,000 mSv) at age 30 increases mortality risk from solid cancers atage 70 an average of about 1.5 times for both sexes. The risk increases in direct proportion
to radiation dose above around 100 to 200 mSv. However, association remains unclear
below that range. If we assume that cancer risk is proportional to radiation without“threshold” (the demarcation point above which there are effects and below which there areno effects), projections indicate that exposure to 100 mSv and 10 mSv increases cancer
risk by about 1.05 and 1.005 times, respectively.

Radiation Risk (lifetime)
Based on the above data, exposure to radiation dose of about 100 mSv atage 30 is thought to increase the lifetime risk of cancer mortality from 20%
without radiation exposure to about 21% (1 percentage point increase) on
average for both sexes. A-bomb exposure was a single acute exposure,while environmental contamination represents chronic exposure. The
effects from chronic exposure, even in the case of the same total dose, arethought to be smaller than the effects from acute exposure (1/2 or 1/1.5).
Based on this theory, chronic exposure to about 100 mSv would increase
lifetime risk by 0.5 to 0.7 of a percentage point. Based on the studies ofA-bomb survivors, it is also known that risk from radiation is larger for those
exposed when young as shown in the table below.

Cancer risk after single 100 mSv exposure
Age at time ofexposure

Sex

Lifetime excess
risk (%)

Lifetime risk without
exposure (%)

10 years of age

Males
Females

2.1%
2.2%

30%
20%

30 years of age

Males
Females

0.9%
1.1%

25%
19%

50 years of age

Males
Females

0.3%
0.4%

20%
16%

Immunological Study
Late effects
Naturalof radiation
aging
Alterations in the immune system associated with aging and A-bomb radiation dose
have been observed in A-bomb survivors. By analyzing the numbers and functional
Alterations in number
changes of various types of immune cells, we study whether aging of the immune
and function ofsystem, a process that appears to be accelerated by radiation, may be related toimmune cells
the increased risk of several aging-associated diseases among A-bomb survivors Radiation
including cardiovascular disease and selected cancers (see the figure at right).
Inflammation
ThymusT cells
cytokines

0.4
0.3
0.2
0.1

Genome Study

1.5

2.0

2.5

Distance from hypocenter (km)This figure shows relationship between distance from the hypocenter and air dose (without shielding), according to DS02.
When a person is exposed to radiation in a typical Japanese house, radiation decreases to half of the doses presented here.

Biological Dosimetry
In addition to the radiation dosimetry system DS02, we use a method utilized sincethe 1960s for studying chromosomes. One cc of blood contains a few million
lymphocytes (one kind of white blood cell). When cells start dividing after being
cultured for two days, chromosomes can be observed. Microscopic examination ofabnormalities called translocations that occur in the chromosomes will reveal
roughly how much radiation someone was exposed to (see the image at right). It isalso possible to estimate radiation dose by using a technique called electron spinresonance (ESR) on the enamel of an extracted tooth.

10Mechanistic Studies of Radiation’s Effects on the Body

0.5

0.00Cancer risk from radiation exposure

100

Estimation of Radiation DoseWith the introduction of an A-bombradiation dosimetry system, it became
possible to estimate individual doses
based on information concerning eachsurvivor’s location and shielding statusat the time of bombing. The current
dosimetry system was introduced in 2002
and is therefore called DS02. DS02 wascreated employing the latest data from
nuclear physics. DS02 estimates are
consistent with measurements obtained
from exposed materials collected after
the bombings, including bricks and tiles.

The numbers of leukemia deaths and cancer cases among A-bomb survivors
exposed to at least 0.005 Sv (5 mSv) in the Life Span Study cohort are shownin the figure at right. The blue portions (about half of leukemia deaths andabout 10% of cancer cases) indicate excess leukemia deaths and cancercases attributable to radiation exposure.

0Children of Atomic-bomb Survivors (F1) Study
The Children of Atomic-bomb Survivors Study conducts research on
such children to determine whether any genetic effects exist that
could be related to parental exposure. An initial study of birth defects
did not reveal any discernable effects. Subsequent studies on
mortality and cancer incidence, chromosome abnormalities, andserum proteins were also conducted, but again no parental exposure
effect was observed. Presently, these mortality and cancer-incidence
follow-up studies are being continued, with DNA studies recentlyinitiated. Starting in 2002, a new clinical study was initiated toinvestigate lifestyle-related diseases that are not observable at birth
but only start to appear in middle age (e.g., hypertension, diabetes
mellitus, etc.). This clinical study is still being conducted today.

It has been found that cancer incidence and mortality are higher among
A-bomb survivors than among the unexposed (see the figure at right). The
largest percentage increase in cancer incidence and mortality due to radiation
exposure is shown for leukemia. Leukemia started to increase two or three
years after exposure, reached a peak after five to ten years, and decreased
thereafter. However, incidence and mortality from leukemia still appear even
now to be slightly higher in A-bomb survivors than in the unexposed. On theother hand, solid cancers (all cancers other than leukemia) started to increaseabout ten years after exposure and have continued to rise with time.

Radiation risk (times)

The Life Span Study is an epidemiological research
program investigating lifetime health effects ofatomic-bomb radiation. Its major objective is to investigate
long-term effects from A-bomb radiation on causes ofdeath and incidence of cancer. About 120,000 subjects
selected from among residents of Hiroshima and Nagasaki
identified through the 1950 national census have been
followed since that time, including about 94,000 A-bomb
survivors and about 27,000 unexposed individuals.

Extent of increase in excess leukemia andcancer mortality due to radiation exposure(schematic diagram)
SolidLeukemia
cancers

Number of deaths
per year

Life Span Study

The image shows a dividing
cell with abnormalities, asindicated by the arrows.
Abnormal chromosomes(translocations) shown in
two colors were produced
by exchange between
segments of two different
chromosomes.

It is said that tendency to develop radiation-related diseases varies with each person.
One of the reasons for this difference is believed to be slight variations in the structureof genes among individuals. Association between risks of development of various
diseases and the entire gene structure (the genome) is being studied worldwide, withthe aim of using such knowledge for prevention of diseases as well as development ofrelated drugs. At RERF, we use some of the blood samples from our clinical study
participants for genome studies, with their consent, for understanding themechanisms that explain how radiation causes diseases for the purpose of preventing
future radiation-related diseases and developing treatments for such diseases.

NK cells
B cells

Persistentinflammation?

Inflammation- andaging-associateddiseases,
e.g., cancer,
Stem cells
cardiovascular
MutationsdiseasesRadiation-related Carcinogenesis Study
We study at the molecular level characteristics of cancers developing from radiation exposure. Normal cells develop into cancer cells
as a result of an accumulation of various gene abnormalities. Many cancers have several patterns in terms of types of related genes
and their abnormalities. Our studies of thyroid and colon cancers suggest that particular patterns (accumulation of characteristicabnormalities in specific genes) are frequently observed in radiation-related cancers.