放射線の人体への影響(生物学)
Effects of Radiationon Human HealthISBN978-4-905025-12-2
大学等放射線施設協議会

113-0032 東京都文京区弥生2-11-16
東京大学アイソトープ総合センター内
電話: 03-5841-3058 Fax: 03-5841-3050
E-mail: kyogikai@ric.u-tokyo.ac.jp

Factors that relate to biological effects(生物学的影響に関する要因)
1. Penetrating ability (透過能)2. Linear Energy Transfer (LET)(線エネルギー付与)

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1. Penetrating Ability of Radiations

Paper

αβγ
Neutronradiation

Aluminum
Acrylic resin

P+nn P+e-n

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Lead(Pb)

H2O(Hydrogen rich)2. Linear Energy Transfer (LET)(線エネルギー付与)
radiationP+

Low LET
radiations(X, γ, β)High LET
radiations(α, neutron)

The energy transferred per
given distance of track

Sparsely ionizing

Densely ionizing＝Ionization(イオン化)
e-Less biological effectMore biological effectLinear Energy Transfer(LET)
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DNA is the Target of Radiations
Indirect action(間接作用)
Ionizing

OH.

e-H2O

(free radical)

P+

Low LET
radiations(X, γ, β)Direct action(直接作用)
Ionizing
eP+
2nm

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High LET
radiations(α, neutron)

Classification of Biological effects of Radiations
on the Human Body・Acute Effects vs. Late Effects(急性影響)(晩発影響)
・Deterministic Effects vs. Stochastic Effects(確率的影響)(確定的影響)・Somatic Effects vs. Genetic Effects(遺伝的影響)(身体的影響)大学等放射線施設協議会

Classification of Biological effects of Radiationon the Human Body
・Acute Effects vs. Late Effects
・Deterministic Effects vs. Stochastic Effects
・Somatic Effects vs. Genetic Effects

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Acute Effects
Symptoms of acute effects and dose delivered(Whole body, single exposure to gamma rays (or X-rays))
Symptoms 症状

Dose (Gy)0.25 or less

Almost no clinical symptoms 影響なし

0.5

Temporary reduction of white blood cells(lymphocytes) 一時的白血球数の減少

1

Nausea, vomiting, whole-body languor, substantial
reduction of lymphocytes(吐き気、嘔吐、全身のだるさ、リンパ球の大幅な減少)

1.5

Radiation sickness to 50% 放射線宿酔1

Death to 5%

4

Death to 50% within 30 days

6

Death to 90% within 14 days

7

Death to 100%
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Late Effects

CorneaCataracts(白内障) : clouding of the lens of the eye

Lens

・Latent period: several years to a few decades
・Do not occur below a single exposure dose

Optic nerveof 2 Sv

EyeCancers (がん)・Latent period: several years to a few decades

Genetic effects (遺伝的影響)
・Could be･ But not verified in human beings so far
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Use a appropriate shieldin front of your eyes

Classification of Biological effects of Radiationon the Human Body
・Acute Effects vs. Late Effects
・Deterministic Effects vs. Stochastic Effects
・Somatic Effects vs. Genetic Effects

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Deterministic Effects vs. Stochastic Effects

しきい値

Deterministic Effects
確定的影響- Acute effects- Cataract

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Stochastic Effects
確率的影響- Cancer, leukemia- Genetic effects

Deterministic effects(確定的影響)
Projected threshold estimates of the acute absorbed dose for 1% morbidity after
whole body gamma ray exposures
Time todevelop effectAbsorbed
dose (Gy)Testes(精巣)3-9 weeks〜 0.1

Testes3 weeks〜6Ovaries(卵巣)< 1 week〜3

Depression of blood formingprocess(造血障害)

Bone marrow(骨髄)3-7 days〜 0.5

Skin reddening

Skin (large areas)

1-4 weeks< 3-6Skin burns

Skin (large areas)

2-3 weeks

5-10

Temporary hair loss

Skin

2-3 weeks〜4

Cataract (visual impairment)

Eye

Several years〜 1.5

EffectTemporary sterility(一時的不妊)
Permanent sterility

Organ/Tissue

ICRP publication 103, pp168, Table A.3.4, 2007
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Deterministic effects(確定的影響)
Projected threshold estimates of the acute absorbed dose for 1% mortality after
whole body gamma ray exposures
Exposed population

Organ/Tissue

Time todevelop effectAbsorbed
dose (Gy)Bone marrow syndrome(骨髄障害)
without medical care

Bone marrow

30-60 days

〜1with good medical care

Bone marrow

30-60 days

2-3

without medical care

Small intestine(小腸)6-9 days〜6with good medical care

Small intestine

6-9 days>6Lung

1-7 months

6Gastro-intestinal syndrome(消化器系障害)Pneumonitis (間質性肺炎)

ICRP publication 103, pp168, Table A.3.4, 2007
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Stochastic effects (確率的影響)
Detriment-adjusted nominal risk coefficients after exposure to radiation at low
dose rate

Exposed population

Cancer

Heritable effects

Total

Whole population

5.5 x 10-2/Sv

0.2 x 10-2/Sv

5.7 x 10-2/Sv

Adult workers

4.1 x 10-2/Sv

0.1 x 10-2/Sv

4.2 x 10-2/Sv

ICRP publication 103, pp53, Table 1, 2007

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Risk Estimate for Cancers (Stochastic Effect)
がんの発生リスクと放射線被ばくとの相関
Actualmeasurement

Incidence ofcancer
Extrapolation

0.5%
Spontaneousoccurrence
100 mSv 200 mSv

Radiation exposure
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3 Sv

Classification of Biological effects of Radiationon the Human Body
・Acute Effects vs. Late Effects
・Deterministic Effects vs. Stochastic Effects
・Somatic Effects vs. Genetic Effects

大学等放射線施設協議会

Somatic Effects (身体的影響)
Effects of radiation limited to the exposed individual, as distinguishedfrom genetic effects, that may also affect subsequent unexposedgenerations.

Genetic Effects (遺伝的影響)
The radiation induced change in the DNA of germ cells resulting inthe passing of the altered genetic information to future generations.

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External Exposures vs. Internal Exposures(外部被ばく)(内部被ばく)Inhalation(呼吸)Trough the skin(経皮)Ingestion(経口)

External exposure

Internal exposure

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Protecting Against External Exposure(外部被ばくに対する防護)3 principles
3原則

As near to the radiation
source as possible

Shield radiation sources.

Shielding遮へいShield

Stay as far away as possible.

Distance
距離Time
時間

Dose rate = K/ R2
K: constant
R: distance

Keep exposure time short !
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Protecting Against Internal Exposure(内部被ばくに対する防護)Intake routes of radioisotopes
RIの内部への取り込み経路

Inhalation
呼吸Ingestion
経口
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Through the skin
経皮 (wound)To Prevent the inhalation of radioisotopes
RIの吸入防止のための設備

Oak Ridge-type hood

Glove box

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Prohibited Matters(禁止事項)
Eating or drinking(飲食)Smoking(喫煙)Wearing make-up(化粧)大学等放射線施設協議会

Radiation-Related Quantities and Units(放射線被爆に関する量と単位)
Absorbed Dose : Gray (Gy)
(吸収線量)- The energy absorbed per unit mass of the material- A fundamental dosimetric quantity (physical unit)- Regardless of the kind of radiation- 1 Gy = 1 J/ kg- Dose not reflect the degree of biological effects

To calculate the risk of irradiation to the human body

Equivalent Dose
(等価線量)
Effective Dose
(実効線量): Sievert (Sv): Sievert (Sv)

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Equivalent Dose & Effective Dose
(等価線量と実行線量)
Equivalent Dose (等価線量: HT ): Sievert (Sv)･ a measure of biological effects on a particular tissues or organs･ HT = ∑wR ・DT, RR

wR ：Radiation weighting factor
DT, R ：Mean absorbed dose for a tissue or organ (Gy)Radiation weighting factor (wR) (放射線荷重係数)
Radiation

Weighting Factor

γ rays & Ｘrays

1

Beta rays

1Proton2

α rays, fission fragments, heavy ion

20

Neutrons

Continuous functionof the energy(ICRP 2007)

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Equivalent Dose & Effective Dose
(等価線量と実効線量)
Effective Dose (E) 実行線量 : Sievert (Sv)

Stochastic effects･ a measure of biological effects throughout the body (cancers or genetic effects)･ E = ∑w ・H = ∑w ・∑w ・D
TTT
RT, RTTR

Tissue weighting factors
Tissue/Organ

HT : Equivalent dose for tissues andorgans
wT： Weighting factor for organs or tissues

Annual average dose per person
Doctors0.24 mSv

Nurse

0.12 mSv

Radiotherapy technicians

0.68 mSv

Those engaged in research

0.01 mSv

Nuclear power plant worker

1.3 mSv
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Red bone marrow
Colon
Lung
StomachBreastGonads
Bladder
Esophagus
Liver
Thyroid
Bone
Brain
Salivary gland
Skin
Others

Weighting factor
0.12
0.12
0.12
0.12
0.12
0.08
0.04
0.040.04
0.04
0.01
0.01
0.01
0.01
0.12(ICRP 2007)

Effective Dose Limits and Tissue Equivalent Dose Limitsfor Radiation Workers (including Researchers)
放射線業務従事者の実効線量と等価線量限度
Effective dose limit

50 mSv/year; 100 mSv/5years

Women

5 mSv/3 months

Pregnant women *1 mSv as internal exposure

Tissue equivalent dose limit
1) Lens of the eye

150 mSv/year

2) Skin

500 mSv/year

3) Abdomen of pregnant women*

2 mSv*From the confirmation of pregnancy to delivery

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Personal Radiation Monitoring (個人被ばく線量系)
Radiation exposure report

Personal monitoring
instrument
Effective dose (実効線量)

Equivalent dose (等価線量)
for the lens, skin and abdomen
Where should a monitoring instrument be worn on?

Men

Women 大学等放射線施設協議会

End of slides

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