Ordinance on Prevention of
Ionizing Radiation Hazards

Radiation work both ways

benefit
tracerelectric source
irradiation

risk

OverexposureHarmful effects

Balance of profit and loss

ICRP(International Commission on Radiological Protection )The "International Commission on Radiological Protection" is aninternational organization that makes recommendations onradiation protection from the standpoint of an expert. The
committee was established at the 2nd Annual Meeting of theInternational Society of Radiology in 1928, and the 1st to 4th
specialized committees were established. The basic concept ofradiation protection, protection standards, radiation protection
measures, etc. are examined, and the results of the examination
are published in the form of recommendations or reports(Publications), which are the norms of radiation protection
standards in each country.

ICRP recommendations and domestic
legislation• In 1958（publ.1）–

The values of protection standards (determined organs / tissues, maximum permissible
dose, occupational exposure: 0.3rem / week, public exposure: 1/10 of professionals) havebeen revised.For occupational exposure to gonads, hematopoietic organs, and crystalline
lens, we recommended the maximum allowable collective dose standard (3rem / 13 weeks,
supplemented by the maximum allowable dose standard) with D = 5 (N-18) rem (N: age).

– Enactment of the Radiation Hazard Prevention Law in 1960

• In 1977（publ.26）–

It presented a dose limiting system featuring three principles: justification of conduct, optimization ofprotection and dose limiting. Instead of radiation dose limits focusing on organs and tissues, werecommended dose equivalent limits based on the total risk of all irradiated tissues.

– Partial amendment of related laws and regulations in 1988;
revised to use the effective dose equivalent limit and tissue dose
equivalent limit for one year as the dose standard.

• In 1990（publ.60）–

The radiation protection system added justification and optimization of the dose limit system, andrecommended a value of "5 year average of 20 mSv per year" for effective dose as the dose limit for
occupational exposure.

– Partial amendment of related laws and regulations in 2000;
revised effective dose limit to 50 mSv in 1 year and 100 mSv in
5 years

Radiation protection goals
Radiation emission
X-reyradioactivity
nuclear reaction
nuclear fission
Protection goals
benefitGoal

Do not limit
unreasonably

risk
Ensuring human safety

Prevents deterministic effects

Reduce the induction of deterministic effec

Radiation protection system●Network
S
S

Justification of the act

S

Protective optimization

User

S

Pubic

●Radiation protection system
action（work environment）①Justification of the act②Protective optimization③Individual dose limit

intervention①benefit ＞ ill effect（ public environment ） ②Content, scale andduration of intervention

・Effects / results ？
・Alternative method ？
・ALARA・Acceptable limit
・Bring some benefits
・ Public exposure situation
・Countermeasures

Atomic Energy Basic Law (1955)
Use atomic energy only for peaceful aims through democratic administration,
autonomous accomplishment and public disclosure of results.

Article 12

Article 20• Regulations concerning
Nuclear Fuel Materials• Law for the Regulation of
Nuclear Source Materials,
Nuclear Fuel Materials andReactors (1957)• Protective Measures ofRadiation Hazards• Law concerning Prevention ofRadiation hazards due toRadioisotopes, etc. (1957)– Enforces the necessary
regulations on manufacture,processing, storage,
reprocessing and disposal
activities of nuclear source
materials, fuel materials andnuclear reactors.

– Regulates the use, sale, lease,disposal and other handling ofradioisotopes, the use ofradiation generating
equipment, and the disposal
and other handling of thearticles contaminated byradioisotopes to prevent
radiation hazards.

大学等放射線施設協議会

Structure of Regulations for Prevention ofRadiation Hazard due to Radioisotopes, etc
The Law
Enforcement
ordinance
Enforcement
regulations

Notification specifying
quantities

Practice
大学等放射線施設協議会

Applicable laws and regulations
related to radiation
１．Law Concerning Regulation of Radioactive
Isotopes, etc.
Does not include X-rays and electron
beams of less than 1 MeV.
２．Industrial Safety and Health Act
Ionizing radiation hazard prevention rules（Ionization rule）
Includes X-rays and electron beams of lessthan 1 MeV.

Contents of the ionization law（１）

Safety management system
Basic principle of radiation hazard prevention,authorized chief X-ray inspection engineer（２）

Human safety management
Education and training, health examination,

exposure measurement and recording, emergency measures（３）

Safety measures for X-ray equipment / X-ray work
Technical standards for protection of external radiation,
records, measurements, alarms, Posting notes, etc.

（４）

Safety measures for γ-ray transmission photography work

（５）

Safety measures for radioactive materials

Prevention of pollution, measurement of working environment

Terms
X-ray ：ionization radiation
X-ray equipment ：radiation equipment
A device that accelerates charged particles
Radiation equipment room
Radiation work
Controlled area

Radiation equipment room
(1) The radiation device will be installed in a
dedicated room (radiation device room).
• Dedicated room: A room that is not used for
purposes other than the use of radiationequipment.
• Multiple radiation devices can be installed in one
room.
• X-ray equipment and γ-ray equipment can beinstalled side by side(2) Post a sign clearly stating that it is a radiationequipment room at the entrance of the room.
(3) Do not allow anyone other than what you need toenter the room.

Radiation work
(1) Use of X-ray equipment or inspection ofequipment that generates X-rays(2) Use of cyclotrons, betatrons and otherdevices that accelerate charged particles, orinspection of devices that generate ionizing
radiation.
(3) These inspection work involving X-ray
equipment, degassing of Kenotron or X-ray
generation(4) Handling of equipment equipped withradioactive substances(5) Handling of radioactive substances or thosecontaminated with radioactive substances.

Controlled area
Definition: A place where there is a risk of
exceeding 1.3 mSv per 3 months① Keep unnecessary people from entering thecontrolled area.
② Post notes in an easy-to-see place in the controlledarea.
Matters necessary to prevent radiation damage• Precautions about wearing of personal dosimeters• emergency measures in the event of an accident③ Do not exceed the public annual dose limit (1msv)
outside the controlled area and where the same
worker stays at all times.

Effective dose limit at each site
Site Boundary : 0.25 mSv / 3 months
Control Area Boundary : 1.3 mSv / 3 months

Region of Regular Entry : 1 mSv / week

Working Area

大学等放射線施設協議会

Exception: When the radiation
device can be used other rooms(1) A device in which the dose rate (H1 cm)
outside the device is shielded to less than
20 μSv / h.
(2) When using the radiation device bymoving it at any time(3) When installing the radiation device inthe radiation device room interferes withthe purpose of use or is extremely difficultin terms of work.

An electron microscope is also a device that
accelerates charged particles.
1. Devices that generate X-rays accessorily, such as electron
microscopes, are not classified as X-ray devices.
2. If the effective dose from ionizing radiation generated fromthe charged particle accelerator may exceed 1.3 mSv / 3
months, a controlled area will be established for
management. Even if it is not necessary to establish acontrolled area, it must be managed so as not to exceed theannual public limit of 1 mSv.
3. The electron microscope is a device that accelerates charged
particles, and X-rays may leak depending on the model andusage conditions of the electron microscope, so it must be
managed so as not to exceed the annual limit of the public.

Contents related to the safe handling of Xrays in the ionization law（１） Safety management system
Basic principle of radiation hazard prevention, authorized
chief X-ray inspection engineer（２） Human safety management
Education and training, health examination, measurement
and recording of radiation exposure,
Emergency measures（３）Safety measures for X-ray equipment and X-ray

work
Technical standards, records, measurements, of externalradiation protection
Warnings, notices posted, etc.

（１） Safety management system(1) Responsibilities of the business
operator and authorized chief X-ray
inspection engineer(2) Work that requires the appointmentof authorized chief X-ray inspectionengineer(3) Duties of authorized chief X-ray
inspection engineer

（１）Responsibilities of the business operator andauthorized chief X-ray inspection engineer

１． Strive to minimize the exposure ofworkers to ionizing radiation
２． Appoint a chief from among thoselicensed as X-ray work chiefs.
✭ Appoint an X-ray work chief to reduce theexposure of X-ray users as much as possible.

the appointment of authorized chief X-ray
inspection engineer
１．One X-ray work chief will be assigned to each controlled area.
2. Post the name of the appointed chief and the work content in aneasy-to-read place.
3. When using a device with an interlock only within the device in acontrolled area, it is not necessary to appoint an X-ray work
chief. However, it is desirable to appoint a person who has thenecessary knowledge as the person in charge of management
and have him / her perform the following matters.
4. Chief administrator(1) While emitting X-rays, always keep the safety device
effectively so that the arms, fingers, etc. cannot enter thedevice.
(2) Take necessary measures to prevent arms, fingers, etc. fromentering the device in the event of an abnormality such as amalfunction.

Duties of authorized chief X-ray inspectionengineer① When using outside the radiation equipment room, clearly
indicate the sign of the restricted area within 5 m from the focal
point and the irradiated object.
② Take measures to properly use the irradiation tube, diaphragm,
and filter plate.
③ Take the measures specified in the measures for indirect
photography, fluoroscopy, and transmission photography.
④ Adjust the irradiation conditions, etc. so that the dose received
by the radiation workers is as small as possible.
⑤ Check the alarm device.
⑥ Confirm that no workers are entering the exclusion zone before
and during irradiation.
⑦ Check if the personal dosimeter is weared correctly.

Penalties
If you violate the provisions of the Industrial Safety and Health
Act, the actor will be punished and the corporation will also be
fined.
１．Example of imprisonment for up to 6 months or a fine of
up to 500,000 yen.
• When a work chief is appointed and the matters specified
by the Ordinance of the Ministry of Health, Labor andWelfare are not performed.
• If you do not take the necessary steps to prevent radiationinduced health problems.
• If no special education did.
• When the work environment is not measured and themeasurement results are not recorded.

２．Examples of fines of 500,000 yen or less• When the X-ray device is used without notification or themain part is changed.

（２）Human safety management: Education
trainingIndustrial Safety and Health Act
When a business operator hires a worker
or changes the work content, he / shemust provide education for safety or
hygiene regarding the work he / sheengages in.
✭Work is not specified.
Ionization law
Special education should be given when
getting into transparent photography
work or when the work content ischanged.

Special education subjects, content, time
subjects

content

time

Method oftransparent
photography work

Work procedure, radiation measurement,
one andradiation exposure prevention law, measures half hourin case of accident

Structure andhandling methodof X-rayequipment

Principles of X-ray equipment, structureand function of X-ray tubes, high voltage
generators and controllers, operation andinspection of equipment

Effect ofionizing
radiation onliving organisms

Types and properties of ionizing radiation, half houreffects on living cells, tissues, organs
and the whole body

Applicable laws
and regulations

Related provisions in the Industrial Safety One hourand Health Act, the Ordinance, theRegulations, and the Ionization Regulations

total

one andhalf hour

4 and halfhours

Attention to education training① Special education may be omitted if the person is recognized
as having sufficient knowledge and skills in all or part of thesubject.
② Record the participants and subjects of special education andkeep them for 3 years.
③ Education will also be provided for short-term employees suchas temporary and part-time employees.

④ Shooting work includes all related work such as assembling theequipment, attaching and detaching films, and moving theequipment at the work place. However, those who are only
engaged in the transportation of equipment (drivers of truck
transportation) are not included.
⑤ Education is not defined for practical skills, but it is desirable toeducate including actual operations.

health checkup
Business operator① Perform initial and regular
health examinations.
② Submit the report to thedirector of the competentlabor standards inspection
office without delay.
③ Create a personal slip andstore it for 30 years.
④ Necessary measures when
there are abnormal findings⑤ Take necessary measureswhen a radiation hazard
occurs.

Worker
① You must undergo a

medical examination
conducted by the business
operator.

② If you do not accept the
medical examination by thedoctor designated by thebusiness operator, you may
undergo a medical examination
by another doctor and submit adocument certifying the result
to the business operator.

health checkup
law

Ionization law

responsibility

Business operator

eligible person Workers engaged in radiation workordinallytime

Timing of hiring or relocation，periodic
intervals

intervals

Per once within 6 months

way

Medical examination by a doctor

Contents of health checkup
1. Presence or absence of
exposure history andevaluation
If exposed① Work place② Contents③ Period④ Presence or absence ofradiation damage⑤ Presence or absence of
subjective symptoms⑥ Other matters related toradiation exposure

2. Inspection items① White blood cellcount, white blood cell
percentage② Red blood cell count,blood pigment amountor Hematocrit value③ Eyes on cataracts④ SkinOmission of health checkup✭Investigation and evaluation of exposure log cannot be
omitted.
✭Inspection can be omitted depending on the conditions(1) Can be omitted depending on the type of radiation source(2) If the doctor deems it unnecessary in the regular healthexamination, some or all of it can be omitted.
● Effective dose of the previous year: less than 5 mSv● Effective dose for the relevant year: Expected to beless than 5 mSv● When the doctor does not deem it necessary● Show the previous dose to the doctor(3) Eyes related to cataract can be omitted

Radiation dose limits for occupational exposure

Effectivedose

Equivalent
doseradiation
workermen

100 mSv/5years
not exceed 50 mSv in any single year

women

5 mSv/3month

women inpregnancy

1mSv for internal exposure until delivery

emergency worker

100 mSv

temporary visitor

100 mSvlens of the eye

150 mSv/yearskin

500 mSv/year

abdomen of pregnant
women

2 mSv until delivery

大学等放射線施設協議会

Radiation exposure management
Legal division of women
Women１
Women２

Women３

Women of childbearing potential
Women diagnosed or offered to
become pregnant
Women diagnosed as unlikely to
become pregnant

Exposure limit for each place
Place
A place where people
always enter
Controlled areaboundary
Establishment
boundary
Hospital, Clinic rooms

Limit
1mSv/week
1.3mSv/ 3 month

250μSv/ 3 month
1.3mSv/ 3 monthConfirmation and recording of
measurement results
divisionOne
Threemonth months

Man, Women3

effective
dose

WomenA（※１）○

WomenB（※２）
Eachequivalent organization
dose
Women２
※１
※２

One
year

Five
years

○

○

○

○

○

○

○

○

○

○

○

○

WomenA：Women１＋Women２
Female A who does not exceed 1.7 mSv / month．Managing each 3monthEmergency procedures
Emergency example
When the shield is damaged and irradiation
cannot be stopped immediately.
Evacuate immediately from the exclusion
zone.
Area where effective dose may exceed 15
mSv

（３）

Safety measures for X-ray

equipment and X-ray work
Technical standards for protection of external radiation,
Record,Measurement,
Alarm,

Posting notes,
otherX-ray equipment classification
1) Classification by safety standards(1) X-ray equipment(2) Specific X-ray equipment
2) Classification by interlock

Classification by safety equipment（１）X-ray equipment
All devices that generate X-rays. There are no
special restrictions on tube voltage and safety
devices.
Handmade equipment for research andeducation（２）Specific X-ray equipment
Among X-ray devices, X-ray devices equipped withstandards and safety devices specified by the Ministry of
Health, Labor and Welfare.

１．Industrial specific X-ray equipment：Non-medical specific X-ray equipment

２．Specific X-ray equipment for medical use

Specific X-ray equipment
Specified X-ray equipment shall not betransferred, rented, or installed unless it
is equipped with the standards or safety
equipment specified by the Minister of
Health, Labor and Welfare.
When installing, relocating, or changing
major parts, notify the Chief of Labor
Standards Inspection Office with
documents and drawings.

Interlock function① The X-ray device must have an irradiation box.

②All or part of the body of the worker engaged in
the work during irradiation must be shielded sothat it does not enter the inside.
③ The structure should be such that X-rays are not
emitted unless the irradiation box door is closed.
④ The structure must not allow the interlock to beeasily released.

Conditions for specific X-ray equipment① X-ray equipment with a rated tube voltage of 10 kilovolts or more based on
the crest value.

② Excludes those that are assembled each time they are used for research or
education of X-rays or X-ray equipment.
③ Excludes medical devices specified by the Pharmaceutical Affairs Law, which

are specified by the Minister of Health, Labor and Welfare. Equipment andmachinery under the Pharmaceutical Affairs Law refer to medical X-ray
equipment and X-ray tubes for medical X-ray equipment.
④ Use an irradiation tube or diaphragm so that the radiation angle of the used
line cone does not exceed the angle required to achieve the purpose of use.
However, this does not apply if the purpose of use is hindered.
⑤ The irradiation cylinder or diaphragm meets the standards set by the Ministerof Health, Labor and Welfare.

Clarification by Interlock(１) Interlock typeCan be used in general laboratories(２) Non-interlock type
Cannot be used in general laboratories① Fixed use: Inside the radiation room (Xray equipment room)② Mobile use: Establish an off-limits area.

Procedure: Notification of X-ray equipment
Notify the Labor Standards Inspection Office.
1. When installing, relocating, or changing
major structural parts
2. X-ray equipment, radiation equipment room
3. Document:① Drawing of the controlled area,② Radiation equipment summary③ Radiation equipment room summarySafety measures for specificindustrial X-ray equipment(1) Irradiation cylinder, aperture,filter plate(2) Measures for indirect shooting(3) Measures for fluoroscopy(4) Measures for mobile use(5) Posting of precautions, etc., suchas alarm devices

（４）Measures for mobile use① Use in the exclusion area.
Exclusion area: Within 5m from the focal
point or subject② Indicate the restricted area with a sign.
③ Keep people out of the direction ofradiation.

（５）Posting precautions such as alarm
devices① Alarm device: When energized
1. Automatic alarm device: red rotating
light, electric bell, buzzer
2. Non-automatic alarm device: manual
buzzer, display② Posting of precautions
1. Use of personal dosimeter
2. First aid in the event of an accident

Measurement of working
environment
Measurement of dose equivalent rate(1)When using fixedly: 1 time / 6 months(2)When not fixed: Once a day(3)Record the results and store for 5 years(4)Calculation when measurement isdifficult(5)Post the measurement results and makethem known

The end.

Enter 0 for correct questions and x for missing questions in parentheses.

( ) 1. The electron microscope is not an X-ray device, so you can use it
freely.
( ) 2. If you have a medical examination once at the beginning, you do
not need to have a medical examination from the next year.
( ) 3. A friend visited me, so I thought I would get permission from theadministrator, but I was absent, so I conducted an experiment together
using an X-ray device without obtaining permission from theadministrator.
( ) 4. I lost my personal dosimeter, so I borrowed a friend's dosimeter.
( ) 5. Since the regular inspection was troublesome, I copied theprevious record as it was.
( ) 6. Since it was difficult to obtain the data, the collimator of the Xray device was removed for measurement.
( ) 7. For the convenience of the experiment, the interlock of the X-ray
device was released and used.
( ) 8. Since the type of collimator of the X-ray device was changed, theleakage dose was remeasured.

[Answer](X) 1. The electron microscope is not an X-ray device, so you canuse it freely.
(X) 2. If you have a medical examination once at the beginning, you do
not need to have a medical examination from the next year.
(X) 3. A friend visited me, so I thought I would get permission fromthe administrator, but I was absent, so I conducted an experiment
together using an X-ray device without obtaining permission from theadministrator.
(X) 4. I lost my personal dosimeter, so I borrowed a friend's dosimeter.
(X) 5. Since the regular inspection was troublesome, I copied theprevious record as it was.
(X) 6. Since it was difficult to obtain the data, the collimator of the
X-ray device was removed for measurement.
(X) 7. For the convenience of the experiment, the interlock of the Xray device was released and used.
(0) 8. Since the type of collimator of the X-ray device was changed,
the leakage dose was remeasured.