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Radiation protection regulation aspect
Anna Maria Motoc
Ádám Salik National Research Institute for Radiobiology and Radiohygiene
Radiation protection • An improper application of the ionising radiation may
harm the health of humans and of fauna and flora, therefore damaging the environment.
• In order to avoid these unwanted effects, for the control of radiation sources
Radiation protection was created
the protection against exposure to ionising radiation.
• Shortly after the discovery of ionising radiations, their users realised that standards of protection had to be developed.
• Due to this concern, the International Commission on Radiological Protection (ICRP) was established in 1928.
International organizations
Inter-governmental organization: • United Nations (UN)
and its subsidiary organization UNSCEAR
(UN Scientific Commitee on the Effect of Atomic Radiation)
4
Specialised organizations
• Word Health Organization (WHO)
• Food and Agriculture Organization (FAO)
• International Labour Organization (ILO)
IAEA - International Atomic Energy Agency Radiation protection recommendations, Publications: Safety Standards, Safety Guides, Safety Recommendations, Safety Requirements.
For the effective operation of radiation protection, it is necessary to have appropriate laws and decrees.
• Complying with these, their revision and development can only be done based on
prescribed constitutional form
Organizations of International radiation protection - the main recommendations and regulations
Basic documents for Hungarian regulation
6
• Governmental regulation – Governments have responsibility for the enforcement
of the standard, generally through a system that includes a Regulatory Authority
• National infrastructure includes: – legislation and regulations (law and decrees)
– a Regulatory Authority empowered to authorize and inspect regulated activities
– sufficent resources
– adequate numbers of trained personnel
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Regulatory Authority
The type of regulatory system adopted in a country depends on:
• the size
• complexity
• safety applications of the regulated practices and sources
• the regulatory traditions in the country
Radiation protection in Hungary Present regulation
ICRP Publication 103. (2007)
IAEA/IBSS
EURATOM Directive 2013/59 (2013)
Act No. CXVI of 1996 on Atomic Energy (modified)
Governmental Decree No. 487/2015
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Act CXVI of 1996 on Atomic Energy
Use of the nuclear energy is regulated by law in Hungary; • the peaceful use of atomic energy promotes the living conditions of humanity
in numerous fields of industry, agriculture, health care, and scientific research;
• however, that the improper application of atomic energy may harm the health of humans and of fauna and flora, and damage the natural environment;
• to ensure that the risk caused by the use of atomic energy is no greater than the socially-accepted risks associated with other activities and to ensure adherence to safety requirements by appropriate national regulations which are in agreement with international regulations;
Act CXVI of 1996 on Atomic Energy
• the Act defines the legal responsibilities of the users of nuclear energy and of the authoriti;
what it means, the nuclear energy peaceful uses? For example: Panoramic X-Ray Equipment, industrial application (radiography)
• the Hungarian Atomic Energy Authority (OAH) is charged with the primary responsibility for regulation and supervision of radiation safety.
Structure of the radiation protection framework
Act on Atomic Energy
Executive Decrees Standards for workplaces
Workplace Radiation Protection Rules
Government Decree No. 487/2015 (XII.30)
on the execution of certain provisions
of Act CXVI of 1996 on Atomic Energy associated with radiation protection
Goal of radiation protection
• to prevent the occurrence of serious radiation induced acute and chronic deterministic effects (e.g., cataracts, skin burns, acut radiation syndrom)
and
• to reduce the potential for stochastic effects (e.g., cancers, hereditary effects) in exposed persons to a degree that is acceptable in relation to the benefits to the individual and to society from the activities that generate such exposures.
Radiation protection requirements
3 principles:
• justification of a practice;
• optimization of protection and safety;
• dose limitation.
Justification of a practice
• No practice involving exposures to radiation should be adopted unless it produces sufficient benefit to the exposed individuals or to society to offset the radiation detriment it causes.
• An activity resulting in the release of ionising radiation may only be licensed in the case that it can be justified that the benefit to society counterbalances the potential adverse consequences of the radiation;
Optimization of protection
the protection and the safety shall be optimized:
• the magnitude of individual doses,
• the number of the persons exposed to radiation
• the probability of the exposures should all be kept as low as reasonable achievable (ALARA), economic and social factors being taken into account.
Optimization of Protection in Dental Radiology
• To be able to apply the principle of radiation protection to dental radiology system including design and Quality Control (QC).
Facts
• Very frequent examination (about 25% of all the radiological
examinations)
• Organs at risk: parathyroid, thyroid, larynx, parotid glands
Optimization of Protection in Dental Radiology
• Technical characteristics of intraoral, panoramic, and cephalometric dental x-ray equipment are summarized, along with operating characteristics
• Although doses are generally low, the high frequency of examinations requires radiation protection and quality control in dental radiology
• Some tests are detailed for quality control of dental equipment. What Tests ?
– Processor QC– most critical – Collimation – Dose – Exposure Time – Half-Value Layer – Kilovoltage (kVp)
How reduce the dose?
Patient dose? PD
Basic radiation protection strategies
• Time (short exposure time)
• Distance (operator)
• Shielding (lead)
Dose limitation
• Is aimed at ensuring that no individual is exposed to radiation risks that are judged to be unacceptable from these practices in any normal circumstances.
• The accumulated radiation doses arising from artificial sources, except the radiation doses arising from medical treatment, shall not exceed the dose limits set forth in the Decree (487/2015).
• Intervention levels relating to emergency radiation doses (urgent protective measures: isolation, evacuation, iodine prophylaxis)
Radiation protection dose limits with respect to workers and public
members
Exposed workers
Students, trainees
(between 16-18 y)
Members of the population
Workers in emergency situation
Effective dose (whole body)
20 mSv/y 6 mSv/y 1 mSv/y 50, 100 and
250 mSv / case
Equivalent dose Eye lenses
20 mSv/ y 15 mSv/y 15 mSv/y
Equivalent dose skins
500 mSv /y 150 mSv/y 50 mSv/y
Pregnant or nursing mother employee can't be employed in radiation jobs.
487/2015 Government Decree
Radiation protection training
Acquisition of radiation protection knowleadge shall be ensured within the framework of training and upgrading training (every five years); subject to examination; depending on the degree of the risk arising from the characteristics of the work: • basic level, • extended level, work in industrial, medical, radiological
areas (handle the radiation source independently, or who supervise such work positions);
• comprehensive level.
23
Order of radiation protection training
• Acquisition of radiation protection knowleadge shall be ensured within the framework of training and upgrading training (every five years)
• Subject to written and oral examination
Licensing procedure
What is need license, when we use to x-ray equipment in Hungary?
X-ray equipment for operation only by Hungarian Atomic Energy Authority license
What needs of the Authority?
• Radiation Protection Description
• Workplace Radiation Protection Rules
Radiation Protection Description
include:
• the organizational (dentistry) structure of the workplace
• technological description of the activity,
• optimization criteria,
• Workplace layout (where is the equipment)
• Certification standards,
Radiation Protection Description
• the quality control program,
• operator dose
• number of employees
• the risk of accidents
• type of equipment and the type of Marketing Authorisation (type quality certificate)
Marketing Authorisation (type quality certificate)
• Any equipment used in the field of the application of atomic energy may only be used if it has been licensed as being suitable from radiation protection point of view and has issued a Marketing
Authorisation (HAEA).
– technical specifications
– Hungarian-language user's manual
– how much the patient dose
– declartion of conformity
Workplace Radiation Protection Rules
include:
• a radiation protection officer name, contact information, job title,
• the tasks of the heads of facility, • technical description of the radiologically hazardous
activities, • a description of the hazardous working area, • the classification of the workers, the requirements related to
monitoring of the internal and external radiation doses of the workers,
• the rights and obligations of workers working in radiation hazardous workplaces,
• an emergency prevention and action plan.
Basic requirements of the workplace radiation protection
radiation protection officer tasks of Radiation protection officer and one deputy,
appointed by the employer in writing; • Working with radiation in accordance with
applicable regulations, • Informing the employees, the organization of
education and access to education records, • organizing and keeping the register of medical
examination • equipment out inspections and measurements,
method and frequency of implementation,
Monitoring radiation doses
• Workers of radiation hazardous workplaces shall divided into two categories from the point of view of the monitoring of their radiation doses.
• Workers classified in group "A" are those in the
case of which the possibility exists that their annual effective dose might exceed the value of 6 mSv, or 3/10 of any of the organ dose limits.
• All other workers shall be classified in group "B".
Dosimetry of workers
• The personnel dosimetry monitoring of the radiation doses originating from external sources is compulsory in the case of workers classified in group “A”.
• A National Personal Dosimetry Service and Registry is operated at the NRIRR.
• The external doses were evaluated by TLD is used. • Dosimeters are distributed to about 16413 people working at about 1300 institutions (about 58% of them in healthcare, 27% in the nuclear energy production). • All data are recorded and preserved when the dose at a single reading exceeds 0.1 mSv.
Working areas classification and monitoring
• Controlled area shall be defined as the working area where the year due to the activities of individual exposure may exceed 1 mSv effective dose. – need to mark the entrance of the radiation hazard
symbol and inscription,
• Supervised area
Special radiation protection and safety rules don't need regular conditions.
-although doses incurred during
dental examinations are in general
relatively low,
-dental radiology accounts for nearly
one third of the total number of
radiological examinations in the EU
- and therefore merits specific
attention with regard to radiation
protection.
Safe Use of X-Ray Equipment
The aim of the study
to provide a practical guide to radiation protection for
professional groups of dentists and their assistants, based
upon the two relevant Council Directives of the European
Union:
– Directive 96/29/Euratom, of 13 May 1996, laying down the
basic safety standards for the protection of the health of
workers and the general public against the dangers
arising from ionising radiation;
– Directive 97/43/Euratom of 30 June 1997, on health
protection of individuals against the dangers of ionising
radiation in relation to medical exposure (Medical
Exposures Directive).
to avoid unnecessary or excessive
exposure to radiation and to improve the
quality and effectiveness of medical uses of
radiation
no exposure to X-rays can be considered
completely free of risk, so the use of
radiation by dentists and their assistants
implies a responsibility to ensure
appropriate protection.
Issues
Dental X-ray equipment
X-rays are an important tool that help dentists to
diagnose, plan treatments and monitor both
treatments and lesion development.
Types of dental radiological procedure:
– intraoral bitewing or periapical radiography
– panoramic examinations
– cephalometric examinations
Intraoral dental X-ray equipment
typical x-ray paramters
U: 65-70 kV
I: 6-7 mA
t: 0,5 sec
skin-source distance
SiD: 20 cm
patient dose (PD)
Effecitve dose
4-5 µSv/exposure
natural background:
~3000 µSv/y (0,1µSv/h
Panoramic X-ray equipment
typical x-ray paramters
U: 70-80 kV
I: 8-10 mA
t: 11-15 sec
skin-source distance
SiD: 25 cm
patient dose (PD)
Effecitve dose
20-30 µSv/exposure Dose limits(employee):
20.000 µSv/y
Protection of the patient
thyroid protection
lead apron
Front??
Behind??
Cephalometric X-ray equipment
typical x-ray paramters
U: 75-90 kV
I: 12 -14 mA
t: 20-40 sec
skin-source distance
SiD: 25 cm
patient dose (PD)
Effecitve dose
200-500 µSv/exposure natural background:
~3000 µSv/y (0,1µSv/h)
Combined technology
Panoramic operation CT operation
Cone Beam CT (CBCT)
Standing
position Seating
position
typical x-ray paramters
U: 75-90 kV
I: 12 -14 mA
t: 20-40 sec
skin-source distance
SiD: 25 cm
patient dose (PD)
Effecitve dose
200-500 µSv/exposure
NOMAD (Aseptico, USA)
EZX-60 (Genoray, Korea)
Mobile intraoral X-ray equipment
Dose received by the operator
due to scattered radiation
(µSv/exp)
Nomad EZX-60
Hand 0.18 2.88
Head 0.01 0.12
Gonad 0.00 0.05
Distance=70-80 cm texp=0.35 s
Acquisition of the licenses
Establishment of the facility
Installation of the equipment
Operation of the equipment
Ceasing of activity
Licensing procedure
Grant conditions of the licenses
First step
radiation protection and safety plan (design) form
radiation protection expert
Establishment, Installation and operation license at the
same time
Workplace Radiation Protection Rules
Setting up of the RP Service, assignment of the RP
officer(s)
Conditions for employees
Age (>18 years)
Pregnant women
Health eligibility (suitability) for the position
Professional aptitude
Acquisition of an appropriate radiation protection training
Radiation protection for medical and veterinary work places
Hungarian Standard: MSZ 824:2017.
RP of the workers and the public
Occupational exposure – not exceed 3/10 of the dose limit ((Goverment Decree 487/2015)
Surroundings (vicinity: dwellings, maternity ward, nursery, school) < 100 μSv
Room design (made by a qualified expert)
Size planning requirements:
size of the basic area in m2, length of side in m (intraoral dental X-ray, inside switchgear 9 m2 / 2.5 m, outside switchgear 4 m2 /1.8 m), room height (2.65 m))
Installation of the dental radiography equipment
Room design Positioning of the examination equipment (focus - wall
distance; in case of two equipments a reciprocal bolt prevents simultaneous activation)
These instructions should detail the responsibility for exposure, positioning of staff, use of protective devices, any restriction on primary beam direction
Adequate auxiliary rooms (waiting rooms, corridors, restrooms)
In case of two equipments a reciprocal bolt prevents simultaneous activation
Design of the facility
Protection of adjacent areas In deciding where to install dental X-ray equipment, it is
essential to consider the likely consequences in terms of radiation dose to staff and members of the public in adjacent areas.
This is particularly important if equipment is located close to a partition wall (i.e. within 1.5m for low workload situations), for any walls or floor in the direction of the primary beam (intraoral and cephalometry) and for high workload use.
Ideally, the advice of a qualified expert should be sought to establish the required wall and floor structural attenuation.
Room layout
It is essential that equipment operators can
position themselves so that they have a view of:
patient, controlled area and ‘X-rays on’ indicator
light.
If the room size is limited, it might be necessary for
staff to position themselves outside the room, in
which case a mirror/camera might be required to
ensure a clear view of the room.
The exposure switch should be located so that the
operator can either remain outside of the
controlled area or be behind a protective screen.
Principles of protection
- X-rays travel in a straight line unless they
interact with matter when their direction of travel
can change.
- The main beam of X-rays emitted by the X-ray
tube is known as the primary beam. When this
primary beam interacts with the patient’s head,
radiation will be scattered in all directions.
Primary and scattered
radiation
Staff protection
Dose limits
– In normal dental practice, effective dose should never exceed the annual dose limit for the workers (and would normally be expected to be lower).
– Likewise, dose to the skin of the hands should be well below the dose limit.
Applying ALARA principle:
“as low as reasonably achievable”
Use of time
Absorbed dose rate:
10 µGy/h
X time = absorbed dose
1 hour = 10 µGy
2 hours = 20 µGy
Use of distance
For a point source of
radiation:
the dose rate falls off as
the inverse of the square
of the distance from the
source
Use of shielding
Protective equipment (walls, leaded doors,
leaded partition wall, leaded apron)
thick 12 cm brick equal 0,5 mm lead
-for intraoral film radiography, the radiation dose in
the primary beam is typically a few mGy at the end
of the cone
-the dose at 1 m – due to scattered radiation – is at
least 1000 times less (a few µGy)
-standing at a distance of 2 m from the patient’s
head will lead to a dose of roughly a quarter of that
received standing only 1 m away
-for scattered radiation, the use of distance alone is
often adequate protection in the dental situation
Results
Patient exposure in dental practices
Individual doses in basic dental radiography (intra-
oral, panoramic and cephalometric) are low, being
equivalent to those associated with a few days of
background radiation.
Individual doses from more complex imaging (CT
scans and multiple slice cross-sectional
tomography) can be substantially higher.
Individual risks in dental radiography are small but
are greater in the younger age groups (below 30) in
which (in many EC member states) dental
radiography is most frequently performed.
Patient exposure in dental practices 2
All X-ray examinations must be justified on an
individual basis by demonstrating that the benefits to
the patient outweigh the potential detriment.
The anticipated benefits are that the X-ray examination
would add new information to aid the patient’s
treatment.
No radiographs should be selected unless history and
clinical examinations have been performed.
‘Routine’ radiography is an unacceptable practice.
Thank you for your attention!
Question? Thank you for your attention!