放射線業務従事者のための教育訓練－講習A・講習X：新規教育－

2013/07/05(Fri.)
Biology, ooe

EFFECT OF RADIATIONON THE HUMAN BODY

Accident example (RI related)１）At Non-Destructive Inspection Co., Ltd., the location of thesealed radioisotope was unknown.
【International Nuclear Event Scale 1】
２）An exposure accident occurred at Sumitomo Test Inspection Co.,
Ltd. due to a radiation generator.
【International Nuclear Event Scale 2】
３）The location of the radioactive isotope during transportation by NRS
Corporation was unknown.
【International Nuclear Event Scale 0】4）Wastewater leaked out of the controlled area from the drainage pipe at Tohoku
University.
【International Nuclear Event Scale 0】
文部科学省 HP

International Nuclear Event Scale
Major
accident

Accident

Seriousaccident

Chernobyl disaster(Soviet Union, 1986)

Accident with wider
consequences

Three Mile Island accident

Accident local
consequences

JOC criticality accident(America, 1979)(Ibaraki, 1999)
Serious incident
Abnormalevent

Incident
Anomaly

Below thecriterion

Deviation

Accident example (X-rays related)
April 28th, 1994
１）While manufacturing an X-ray diffractometer (RINT2500, 50kV,200mA), the shutter was disassembled without knowing that X-rays
were being emitted in order to find the cause of the X-rayleakage. He was exposed to the right palm for about 3 seconds,
but when he felt warm at the bases of his 4th and 5th fingers (?),
He noticed the exposure and turned off the power.
２）At this point, there were no particular symptoms, and notreatment was performed.
14 days after exposure３）A part of the skin turned white and the change worsened, so
he reported to the company and visited the Department ofRadiology, University of Tokyo Hospital.
４）The estimated skin absorbed dose was 100-200 Gy.
RADIOISOTOPES, 44, 440-450 (1995)

X-ray exposure disorder

RADIOISOTOPES,44,440-445(1995)

29 days

22 days

55 days

36 days81 days

Balance of radiation utilization

Benefit

RiskScales

Radiation injury begins with one cell death!
Carcinogenic mechanism from non-dead cells
Cells with DNA damage

Independently proliferating cells

Normal cells

DNA damage inducers: radiation, chemicals, viruses, etc.

Inside information
lifespan
Aging
Predisposition (responsible locus)

Cell deathRadiation track model in tissue
NucleusCell

β rayWhereionization
occurred

γ ray, Ｘ-ray

Difference in ionization by radiation
CationElectron

α ray

β ray
Short-wavelength

γ ray
X-ray

Long-wavelength

When radiation passes through a substance, it gives its energy to atoms
and molecules along the way, causing ionization and excitation.

Table. 1-3 Average of radiation tracks in water (living body)
Radiation

LET:L∞(keV/μm)

60Co γ ray

0.3
2.5
3.3～3.8
5.51217456186
140200250kVp X-ray
170～200kVp X-ray
3H β- ray
14MeV neutron (7MeV proton)
4MeV neutron (2MeV proton)
Fission neutrons (0.95MeV proton)
8.3MeV α ray
3.4MeV α ray
5.2MeV α ray
10B(n,α) α ray
出展：医学のための放射線生物学

坂本澄彦、佐久間定行

編著

秀潤社 P12

DNA is an important radiation target that is
the origin of the biological action of living cells.

DNABaseAdenine
GuanineThymineCytosine

High LET radiation: direct action
Low LET radiation: Indirect action (radical generation by radiolysisof water)・H ・OH eaq

Evidence of radiationinduced DNA damage

DNA double-strand break in the nucleus（γ-H2AX immunostaining）

Radiation-induced DNA damage and repair
Base damage

Repair enzymeRadiation

RepairSingle chain
break
Doublestranded DNA
Doublestrand break

Apoptosis
Repair failure

Biological effectDamageSpontaneous（/cell/day）

Radiation induction（/cell/Gy）

Base damage

20,0006,400

Single chain break

50,000600 - 1,000

Double-strand break

1016 – 40

放射線障害の程度を決める要因
放射線感受性
放射線の種類・エネルギー (放射線荷重係数、RBE)
組織 (組織荷重係数)
部位
内部被ばく（核種、摂取量・形態、有効半減期)
細胞周期（G2期DNA合成終期～M期細胞分裂期が感受性大)年齢
健康状態

線量率効果、酸素効果、温度効果
放射線増感物質、放射線防護物質など

Differences in radiosensitivity by tissue

Bergonie-Tribondeau’s Law"The higher the cell division ability,
the longer the cell division process,and the more morphologically andfunctionally undifferentiated, thehigher the radio sensitivity."Order of radiosensitivity of cells
１．lymphocytes
２．Neutrophils (and eosinophils)
３．Epithelial cells１）The basal epithelium of a secretory gland, especiallythe pancreatic juice gland２）Testicular seminoma or ovarian follicle epithelium３）Skin basal epithelium, mucosal layer andgastrointestinal basal epithelium４）Alveolar epithelium, bile duct epithelium５）Tubular epithelium of the kidney
４．Endothelial cells of blood vessels, pleura, peritoneum
５．Connective tissue cells
６．Muscle cells
７．Nerve cell

Effects of radiation on the human body
Acute disorders(erythema, hair loss)
Physicaleffects

Disorders of fetal
development(morphologicalabnormalities / mental retardation)

Deterministic Effects

Cataract
Late disorder
Cancer /leukemia

Stochastic Effects
Hereditaryeffects

Hereditary disorders(congenital anomalies)Occurrence

Deterministic Effects

No clinical symptoms

Threshold

Exposure dose

Stochastic Effects

Occurrence

Radiation effects could not be confirmed
at dose increase <100 mSv (withinspontaneous rate fluctuation)

Radiation effects confirmed
at dose increase >100 mSv

Spontaneous rate

Assuming an 0.5% increasein impact per 100 mSv
Increased dose added to natural radiation

Deterministic Effects vs. Stochastic Effects

Deterministic
Effects
Threshold value
Severity

100500Dose(Gy)Deterministic Effects andThreshold value
TissueBonemarrow

EffectLeukopenia

0.5

Red blood cell depletion

2–6

Thrombocytopenia

2-6

ManInfertility
Women

Eye

Absorbed dose（Gy）

Opacified lensCataract

Temporary infertility

0.15

Permanent infertility

3.5 – 6Temporary infertility

0.65 – 1.5

Permanent infertility

2.5 - 7
0.5 – 25

Deterministic Effects andThreshold value
TissueEffect0.05 – 0.1Fetus

Embryo death/abortion
Malformation
Mentaldevelopmental delay
Temporary erythema

0.12 – 0.2

Temporary hair loss

3Necrosis

18

Skin

Absorbed dose（Gy）

0.1

2Systemic exposure dose and symptoms
Dose（Gy）

Effects

０.０５〜０.２５

Minimum dose at which changes can bedetected by chromosomal analysis (no change inblood image)

０.５〜０.７５

Minimum dose at which changes are detected
for a particular person

０.７５〜１.２５

The lowest dose that is thought to cause nausea
in about 10% of exposed people

１.５〜２Dose (acute exposure) that is thought to cause
temporary helplessness and obvious changes inblood image to most of the exposed people

３〜４

50% lethal dose: LD50, short-term acuteexposureAcute radiation sickness [large intestine]

Large intestine of exposed
person (6 Gy or more)

Control【長崎原子爆弾の医学的影響（長崎大学、1995）より抜粋】

StochasticEffects
100Occurrence(%)
500Dose(Sv)確率的影響を示す場合

実効線量:(Sv)等価線量(Sv):HTR
臓器・組織Tの吸収線量 DTR(Gy)
放射線荷重係数 WR
HTR＝WR×DTR
実効線量(Sv):E
組織荷重係数 WT

E＝ ΣWT ・HTRT

出典：田内広,馬田敏幸,立花章

J.Plasma Fusion Res. Vol88,No2(2012)119-124

(出典：田内広,馬田敏幸,立花章

J.Plasma Fusion Res. Vol88,No2(2012)119-124)

Nominal carcinogenesis risk factor（Radiation handler）

ICRP1990

4.8 x 10-5 / mSv

ICRP2007

4.1 x 10-5 / mSv

If you have been exposed to the annual average doselimit (20mSv) for 40 years
4.1 x 10-5 x 20 x 40 = 0.0328
328 persons / 10000 persons

Increase in cancer and leukemia
caused by radiation
The ICRP calculates that if 1000 people receive 100 millisieverts in accumulation, about 5
people could die of cancer. About 30% of Japanese people today die of cancer in their lifetime.

Increase in cancer and leukemia caused by radiation
Increased mortality only affected radiation
Percentageof people
dying fromcancer

Cancer due to personal lifestyle

0DoseRisk comparison(approximate annual death toll per 100,000 population)
All-case

848.5

Radiation carcinogenesis(Radiation handler)

4.1

Cancer255.1

Water accident

0.70Heart disease

135.4

Influenza

0.55

Cerebrovascular disease

103.9

Murder0.52

Smoking carcinogenesis(current situation)

80.0

Natural disasters

0.10

Smoking carcinogenesis

30.0

H I V

0.04

Suicide23.9

Food poisoning

0.004

Traffic accident

9.1

Lightning strike

0.002

Radiation carcinogenesis (Generalpublic)

5.5

Creutzfeldt-Jakob disease byBSE-infected cattle

0.0009

いろいろな事項についての10万人あたりの年間死亡数、体質研究会、http://www.taishitsu.or.jp/risk/risk2006.html
リスクのモノサシ、中谷内一也、NHKブックス

“IT'S EASY TO BE TOO OPTIMISTICOR SCARED, BUT IT'S HARD TO BE
LEGITIMATELY SCARED. “(TORAHIKO TERADA)

When using radiation, it is essential tolearn the correct knowledge about
handling and management, and to be
humble and fearful.