Mar. 31, 2020

Safe Handling of Radiation
General Handling

ISBN978-4-905025-02-3
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

Contents
•
•
••
•
•
•
•
•
•

Principles of radiation protection
Protection from radiation exposure
Before using radiation
Preparation for actual work
Checking of the equipment
Entering the controlled area
Working in the controlled area
Radioactive waste
Accidents
When leaving the controlled area
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The Principles of Radiological Protection(ICRP Publication 103, p88-89, 2007)• Justification– Any decision that alters the radiation exposure situation
should do more good than harm.

• Optimization of Protection– The likelihood of incurring exposures, the number of people
exposed, and the magnitude of their individual doses should
all be kept as low as reasonably achievable (ALARA), taking
into account economic and societal factors.

• Application of Dose Limits– The total dose to any individual from regulated sources inplanned exposure situations other than medical exposure ofpatients should not exceed the appropriate limitsrecommended by the ICRP.
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benefitrisk

Using radiation is likely
to “cut two ways”

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threshold100
frequency (%)

 Deterministic effects
 should be prevented
 killing/malfunction of cells following
doses higher than the threshold harmful tissue reactions

500radiation dose10
risk (%)

 Stochastic effects
 should be limited to below theunacceptable level mutation of somatic or germ cells
 cancer and heritable effects

50radiation dose
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When you handle radioisotopes and accelerators ...
Please consider
yourself
nearby workers
general public Workers themselves have a primary responsibility for safety.
 Past experience has demonstrated that it is impossible to expect
perfection with respect to radiation safety handling, even in thecase of highly experienced workers.
 Accidents are caused by insufficient and lack of consideration of

the initial prudence while accustoming to the operation.
 A manager responsible for radiation protection is needed, who

can advise on safety issues from the standpoint of a third person.
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Types of Radiation Exposure
External Exposure

Internal Exposure

The radiation source is
outside the human body.

The radiation source isinside the human body.

You should pay attention to these types of exposure.
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Principles of Protection from External Exposure

Exposure dose

The shorter the time, thesmaller the doseTime
Doubling the distancefrom the source quarters
the radiation dose

Distance

Exposure doseTime

Use appropriate
shieldingShieldingExposure dose

Distance

Thickness
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Time

Radiation dose increases in proportion to time.
– Make the working time as short as possible!
– Do a “Cold run” practice and understand the individual steps of eachprocedure.

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Distance• The radiation dose decreases in inverse proportion tothe square of the distance from the radiation source.
– Keep as much distance between yourself and the radiation
source as possible!
– Don’t touch the radiation source directly.
– Use remote handling equipment such as tongs or forceps.
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Shielding
paper

aluminumplastic

α ray
β ray
γ(X) ray

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leadShielding

You can protect yourself from radiation exposureby shielding the radiation source.
Radiation type

Shielding material

β -rayaluminum board (several mm)
plastic acryl board (several cm)

γ-ray

lead block, iron block, concrete block

neutronblock containing boron, water
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Shielding
Shielding of β-ray

Shielding of γ-ray

Plastic or acryl board

lead blocklead glass(glass board containing lead)concrete

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Shielding for β-ray (32P, 5kBq)
Equipment

10000

ResultThickness ofacrilate (mm)Count rate(cpm)Count rate background010448

10424

15248

5224

31011

987

560

36

734

10933

9Background240
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5000

00

2

4

6

Thickness (mm)810Shielding for γ-ray (60Co, 37MBq)
Equipment

ResultThickness ofshielding (cm)10000

Lead(cpm)

Acrylate(cpm)

09271

15226

23142

5630

Acrylic resin

9271
50007089
Lead

791004244553
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02

46Thickness（cm）

810

Protection against Internal Exposure
Unsealed radioisotopes can enter into the body through thefollowing three intake routes

Inhalation

Ingestion

Percutaneous uptake

Through therespiratory system

Through thedigestive system

Through the skin,especially a wound

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Protection against Internal Exposure•

Protection against internal exposure can be attained by faithfully
observing all rules and guidelines.

•In the controlled area, rules are as follows;•Inhalation

Turn on the switch of the ventilation system
Use a hood or glove box

Ingestion

Don’t eat! Don’t smoke!

Percutaneous uptake

Wear gloves at all times

Whenever you exit from the controlled area, the surface of yourhands, clothes, and any equipment brought out from thecontrolled area must be checked for contamination.
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Protection against Internal Exposure
When you handle volatile and/or high-concentrated
radioisotopes, please use a hood or glove box.

hoodglove box
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Before using radiation• You must understand the characteristics of theradiation source• What kind of radiation?
– α-ray, β-ray, γ-ray, X-ray, or neutron• Which type of radiation source?
– Radioisotope• Sealed or Unsealed– Radiation Generating Equipment• Cyclotron, Synchrotron etc.
– Radioisotope-equipped device• Irradiator etc.
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Characteristics of radioisotopes used in life science
Nuclide

3H

14C

32P

35S

125I

Radiation(energy)β(18.6keV)

β(0.156MeV)

β(1.709MeV)

β(0.167MeV)

γ(35keV)X(27-32keV)

Half-life

12.3y

5370y

14.3d

87.4d

59.6d

Detection

Smear andLiquid
scintillation
counterGas-flowcounter

GM detector

Gas-flowcounter

Scintillation
detector

Monitoring
internal
exposure

Bioassay(urine)Bioassay(urine orrespiration)

Bioassay(urine)Bioassay(urine)Scanning of
thyroid glandRange

6 mm (air)
6 µm (water)

24 cm (air)0.28 cm(water)

790 cm (air)
0.8 cm(water)

24 cm (air)0.28 cm(water)

Shielding

No need

Acrylic resin(1 cm)

Acrylic resin(1 cm)

Acrylic resin(1 cm)

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Lead(0.02 mm)

Useful radioisotopes in life science
NuclideHalf-life

3H

12.3y

14C

5370y

Application
cell proliferation (thymidine uptake)micro-autoradiographylabeling of organic compounds
pharmaco-dynamics
labeling of probes for hybridization

32P

14.3d

35S

87.4d

metabolic labeling

51Cr

27.7d

cytotoxic assay

kinase assays

receptor binding assay
125I

59.6d

radioimmunoassay
labeling of peptides
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Preparation for Actual Work• Cold run• Check the equipment you need
– Personal dosimeter– Survey meter– Shielding materials– Laboratory instruments– Radiation protection gear (clothes, gloves, slippers, etc.)• Don’t bring any unnecessary equipment into thecontrolled area.
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Cold Run

You should conduct a “cold run” to understand each step ofexperimental procedures before using radioactive materials.

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Personal dosimeters

Luxel badge

Glass badge

Pocket dosimeter

Personal dosimeter
Personal dosimeterfor females

for males
Put on the chest formales

Put on the abdomen for females
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Survey meters
β-rayslow energy

high energy

3H, 14C

32P

3H/14C survey

GM survey
meter

meter

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γ-raysneutrons

Ionizationchamber

Rem counterEntering the controlled area

• The time of getting in and out of the controlled areafor each radiation worker is automatically recorded.
• The radiation safety officers check the individual
period of stay inside the controlled area.
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Ventilation system

To minimize internal exposure, turn on the ventilation
system when you enter the controlled area.
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Using unsealed β-ray source
Prepare this equipment before you start working.
Survey meter

High energy (32P)

Low energy (3H, 14C)

Geiger-Müller (GM) counter

3H/14C Survey meter

Shielding material

Plastic or acryl board
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Using unsealed γ-ray or neutrons
Survey meter

γ-rayneutrons

Rem counter
Neutron occurs when using
Radiation Generating Equipment(Cyclotron, Synchrotron etc.)

Ionization chamber
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Shielding materials for γ-ray

lead blocklead glass(glass board containing lead)concrete

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Example of working area for unsealed
radioisotopes
Prepare thesurvey meterand keep theswitch on.

Preparetemporarywaste
containers
adjacent to theworking area.

Set theappropriate
shieldingmaterial.

Cover the polyethylene-coated paper
sheet on the surface of a lab bench.

Treat the radioisotope in the tray
covered with polyethylene-coatedpaper sheet.

You should not bring any unnecessary items into the controlled area.
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For working safely in the controlled area•

Understand the law concerning prevention from radiation hazards
due to radioisotopes, etc.

•Understand the nature of radioisotopes and use them in an
appropriate manner•

Understand the effects of radiation on humans and the environment•Handle radioactive substances appropriately to prevent
contamination•

Dispose of radioactive waste by authorized routes•

Follow the emergency procedures in case of natural disaster or fire
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Attitude

Don’t be overly afraid

Don’t panic

Don’t take things too lightly

You should be accompanied by your instructor or experienced person
at your first radiation work.
If you have any problems, ask the radiation protection supervisor and/orradiation protection officers (staff members of the RI facility).
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Measures against contamination

When you use the hood, don’t forget to cover the tray with apolyethylene-coated paper sheet.
Don’t touch the radiation source directly.
Use the remote handling equipment such as tongs or forceps.
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Measures against contamination

use a tray

use a cart

use a bucket

To avoid accidents, use of a tray, a cart and a bucket is recommended.
The surface of a tray and a cart should be covered with polyethylenecoated paper sheets.

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Decontamination protocol
Reagent
Hand / Skin

Clothing

ProtocolNeutral surfactant

Spread powder over spilled area
and wet brush under tap water

Titanium oxide paste

Use together with neutral surfactant

Neutral surfactant

Use washing machine

Cut and fixGlasses

Neutral surfactant
EDTA, Oxalate

MetalUse as 3% warm solution

dil. Nitrate
10% ammonium citrate

Plastic

Neutral surfactant
EDTA
10% ammonium citratedil. Acid

Painted surface

10% Sodium phosphate
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Radioactive waste

Classification by the Japan Radioisotope Association
Combustible Type I

Paper, cloth, wood pieces

Combustible Type II

Plastic tube, plastic vials, polyethylene sheets rubber gloves

Incombustible

Glass vials, other glass equipment, syringe needles, vinyl chloridepipes, vinyl chloride sheets, silicon tubes, ceramics, aluminum foil,material containing lead, Teflon products

Incompressible andIncombustible

Soil, sand, iron bars, pipes, concrete pieces, castings, clock parts,
large amounts of TLC plate, machinery and equipment

Animals

Animals after being dried

Inorganic liquids

Fluids after testing

Combustible filters
Normal filters

HEPA filters, pre-filters, charcoal filters
HEPA filters, pre-filters, charcoal filters
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When leaving the controlled area• Wash hands and check for contamination on handsand feet.
• Change clothes and shoes.
• Check for contamination on everything taken out of
the controlled area (notebook, pen, calculator, etc.)

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Accidents

If you encounter any accidents such as fire or earthquake.

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In case of accident• At first, think and act to save yourself.
– Escape to a safe place– Notify other workers in a loud voice– Push the emergency button• If time permits, take action to prevent expansion of
the accident.
– Bring the radioisotope back to the storage room
– Extinguish the fire at an early stage• Notify the radiation protection supervisor or radiation
protection staff members.
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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
1. Penetrating ability
2. Linear Energy Transfer (LET)

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1. Penetrating Ability of Radiations

Paperαβγ
Neutronradiation

Aluminum
Acrylic resin

P+ nn P+e-n

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LeadH2O(Hydrogen rich)2. Linear Energy Transfer (LET)
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

Less biological effectMore biological effecte-Linear Energy Transfer(LET)
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DNA is the Target of Radiations
Indirect action
Ionizing

OH.

e-H2O

(free radical)

P+

Low LET
radiations(X, γ, β)Direct action
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
・Deterministic Effects vs. Stochastic Effects
・Somatic Effects vs. Genetic Effects

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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))
Dose (Gy)

Symptoms

0.25 or less

Almost no clinical symptoms

0.5

Temporary reduction of white blood cells(lymphocytes)

1

Nausea, vomiting, whole-body languor,
substantial reduction of lymphocytes

1.5

Radiation sickness to 50%

1Death 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 : 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
・Latent period: several years to a few decades

Genetic effects
・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

Deterministic Effects- Acute effects- Cataract

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Stochastic Effects- Cancer, leukemia- Genetic effects

Deterministic effects
Projected threshold estimates of the acute absorbed dose for 1% morbidity afterwhole body gamma ray exposures

Time todevelop effectAbsorbed
dose (Gy)Testes

3-9 weeks〜 0.1

Testes3 weeks〜6Ovaries< 1 week〜3Depression of blood forming
process

Bone marrow

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
Permanent sterility

Organ/Tissue

ICRP publication 103, pp168, Table A.3.4, 2007
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Deterministic effects
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
without medical care

Bone marrow

30-60 days

〜1with good medical care

Bone marrow

30-60 days

2-3

without medical care

Small intestine

6-9 days〜6with good medical care

Small intestine

6-9 days>6Lung

1-7 months

6

Gastro-intestinal syndrome

Pneumonitis

ICRP publication 103, pp168, Table A.3.4, 2007
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Stochastic effects
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)

Actualmeasurement

Incidence ofcancer
Extrapolation

0.5%
Spontaneous
occurrence
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

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Somatic Effects
Effects of radiation limited to the exposed individual, as distinguishedfrom genetic effects, that may also affect subsequent unexposedgenerations.

Genetic Effects
The radiation induced change in the DNA of germ cells resulting in
the passing of the altered genetic information to future generations.

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External Exposures vs. Internal Exposures
Inhalation
Trough the skinIngestion

External exposureInternal exposure

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Protecting Against External Exposure
3 principles

As near to the radiation
source as possible

Shield radiation sources.

ShieldingShieldStay as far away as possible.

Distance
Dose rate = K/ R2
K: constant
R: distanceTime
Keep exposure time short !
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Protecting Against Internal Exposure
Intake routes of radioisotopes

Inhalation

Ingestion
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Through the skin(wound)To Prevent the inhalation of radioisotopes

Oak Ridge-type hood

Glove box

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Prohibited Matters
Eating or drinking

SmokingWearing make-up

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Radiation-Related Quantities and Units
Absorbed Dose : Gray (Gy)- 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
Effective Dose

: Sievert (Sv): Sievert (Sv)

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Equivalent Dose & Effective Dose
Equivalent Dose (HT ) : Sievert (Sv)･ a measure of biological effects on a particular tissues or organs･ HT = ∑wR ・DT, RRwR ：Radiation weighting factor
DT, R ：Mean absorbed dose for a tissue or organ (Gy)Radiation weighting factor (wR)
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
Effective Dose (E) : Sievert (Sv)

Stochastic effects･ a measure of biological effects throughout the body (cancers or genetic effects)･ E = ∑w ・H = ∑w ・∑w ・DTTT
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
StomachBreastGonadsBladder
Esophagus
Liver
Thyroid
BoneBrain
Salivary gland
Skin
Others

Weighting factor
0.12
0.12
0.12
0.12
0.12
0.08
0.04
0.04
0.04
0.04
0.010.01
0.01
0.01
0.12(ICRP 2007)

Effective Dose Limits and Tissue Equivalent Dose Limits
for Radiation Workers (including Researchers)

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
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?

MenWomen
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End of slides

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