AERB GUIDELINES FOR X RAY AND CT INSTALLATION

DR AABID AL RAHIMAN

ATOMIC ENERGY REGULATORY BOARD

• The Mission of the AERB is to ensure the use of ionising radiation and nuclear energy in India does not cause undue risk to the health of people and the environment.

• The Atomic Energy Regulatory Board (AERB) was constituted on November 15, 1983 by the President of India by exercising the powers conferred by Section 27 of the Atomic Energy Act, 1962

FUNCTIONS

• AERB of india recommends and lays down guidelines regarding the Specifications of medical x-ray equipment

• For the room layout of x-ray installation,

• Regarding the work practices in x-ray department , the protective devices and also the responsibilities of the radiation personnel, employer and radiation safety officer (RSO).

• AERB is the authority in India which exercises a regulatory control on the approval of new models of x-ray equipment and the layout of any new proposed x-ray installation.

• It also is the regulatory authority for registration and commissioning of new x-ray equipment, inspection and decommissioning of x-ray installation, certification of a RSO and of service engineers and also for imposing penalties on any person contravening these rules

• The AERB implement the safety provisions by secondary legislation,viz, Atomic Energy (Radiation Protection) Rules-2004, which provides necessary regulatory infrastructure for effective implementation of radiation protection program in India

REGULATORY REQUIREMENTS

DESIGN CERTIFICATION

• Every medical diagnostic X-ray equipment shall meet the design safety specifications stipulated in the AERB safety code

• The manufacturer/vendor shall obtain design certification from the competent authority prior to manufacturing the X-ray equipment.

TYPE APPROVAL/NO OBJECTION CERTIFICATE

• Prior to marketing the X-ray equipment the manufacturer shall obtain a type approval certificate from the competent authority for indigenously made equipment.

• For equipment of foreign make, the importing/vending agency shall obtain a No Objection Certificate (NOC) from the competent authority, prior to marketing the equipment

• Only type approved and NOC validated equipment shall be marketed in the country.

LAYOUT APPROVAL AND REGISTRATION

• Once the X-ray unit is installed, it should be registered with AERB along with lay out approval.

• In the case of CT and cathlab, one has to get licensee for operation along with lay out approval.

• For registration and license, quality assurance tests and nomination of RSO is mandatory.

STEP- BY-STEP GUIDELINES FOR SUBMISSION OF LAYOUT PLAN IN DIAGNOSTIC RADIOLOGY FACILITY

1) Decide a suitable room for housing an X-ray unit to facilitate the easy movement of staff and patient positioning.

2) Room should have preferably one entrance door and window if present, should be above 2m from the finished floor level outside the x-ray room.

3) Door should have a hydraulic mechanism to ensure that door is closed during procedure and should be provided with overlapping at the joints to avoid streaming.

4) Identify the walls as Wall A, Wall B, Wall C & Wall D (in any sequence)

5) Position the location of the equipment for each modality as follows: a) Radiography and Fluoroscopy equipment:

• Couch, Control console and chest stand placed in such a way that chest stand is on the opposite wall of the entrance door and the control console.

• Mobile protective barrier with lead equivalent glass viewing window should be positioned in such a manner that the operator is completely shielded during the exposure.

• Control console should be positioned as far away as possible from the x-ray tube.

b) Computed Tomography and Interventional radiology equipment: Gantry / C-Arm, Couch, Separate control console room, viewing window, - Position the gantry and couch such that the patient is completely visible from the control console, during the scanning - The entrance door to the gantry room from the control console shall have similar requirements as the patient entrance door.

c) Mammography/ OPG/ CBCT: Control console, Equipment and Protective barrier Positioning of equipment should be as far as possible from the door and the control console.

6) Decide on the material and thickness of walls and door

7) Measure the distances of all the walls, doors, windows from the centre of the couch

8) The required shielding of any material shall be provided at least up to the height of 2m from external finished floor of x-ray room

ELORA REGISTRATION & RADIATION PROCUREMENT APPROVAL FOR CT, DR & MAMMO EQUIPMENTS.

•AERB PROCESS• • Step 1: Creation of account in e-LORA for User ID & password • The following documents are required to complete step1• A) Proof of Identity and Date of Birth (of employer): Acceptable documents are as follows:• Passport/Driving License/Photo identity document/card having serial number and date of birth

issued by Central/State Government or PSU (Residential Address should be mentioned)• B) Proof of Employership:• Example: (i) Appointment Letter of Employer, (ii) Board Resolution, (iv) Proprietor’s self

declaration on institute letter head affixed with institute seal

• C) Copy of any one of the document (in the relevant position) for the proof of existing of institute:

• 1)PAN of Institute• 2)TAN of Institute• 3)Registration with State/Central/Local Government Authority• D)Proof of Identity and Date of Birth : Passport/Driving License/Photo identity

document/card having serial number and date of birth issued by Central/State Government or PSU (Residential Address should be mentioned)

• E)E-Mail id of Institute as well as Personal e-mail id.• F)Employers Mobile No .............• After Registration e-LORA will issue user ID & Password.•

• Step 2: Radiation Procurement approval letter• Remarks: Upload of AERB layout drawing signed by Hospital authorities &

Type approval certificate in AERB portal and getting Radiation Equipment procurement approval certificate.

• • Step 3: QA report for Applying for License• Step 4: TLD Badges for Doctor/Operator• Step 5: Qualified Technicians• Step 6 : Approved RSO• Step 7 : Radiation License Certificate•

INSPECTION OF X-RAY INSTALLATIONS

• The diagnostic X-ray installations shall be made available by the employer/ owner for inspection, at all reasonable times, to the competent authority or its representative, to ensure compliance with the safety code.

DECOMMISSIONING OF X-RAY INSTALLATIONS

• Decommissioning of X-ray equipment shall be registered with the competent authority immediately by the employer/owner of the equipment.

CERTIFICATION OF RSO

• Any person accepting assignment to discharge the duties and functions of RSO in diagnostic X-ray installations shall do so only after obtaining certification from the competent authority for the purpose.

• Such certification shall be granted on the basis of adequacy of the person’s qualification, experience and testing/survey/dosimetry equipments availability.

CERTIFICATION OF SERVICE ENGINEERS

• Only persons holding valid certificate from the competent authority shall undertake servicing of X-ray equipment.

• Certification shall be granted on the basis of qualifications, training, and experience and safety record of such person and availability of servicing facilities

RESPONSIBILITIES OF THE EMPLOYER(RULE 20)• 1. Every employer shall:• i. Ensure that provisions of these rules are implemented by the licensee, RSO and other

workers.• ii. Provide facilities and equipment to the licensee, RSO and other worker to carry out their

functions effectively.• iii. Obtain dose records and health surveillance report of the workers from their former

employer.• iv. Provide dose records and health surveillance reports of the worker to the new

employer.• v. Furnish to each worker dose records and health surveillance reports of the worker

annually.• vi. Inform the competent authority if the licensee or the RSO or any worker leaves the

employment.• vii. Arrange for health surveillance of workers.

• 2. The employer shall be the custodian of radiation sources in his possession and shall ensure physical security of the sources at all times.

• 3. The employer shall inform the competent authority, within twenty four hours, of any accident involving a source or loss of source of which he is the custodian.

RESPONSIBILITIES OF THE LICENSEE (RULE 21)• 1. The licensee is responsible for the implementation of terms and conditions of the

license.

• 2. The licensee shall comply with the surveillance procedures, safety codes and safety standards, specified by the competent authority.

• 3. Licensee shall establish written procedures and plans for controlling, monitoring and assessment of exposure for ensuring adequate protection of workers, members of the public and the environment and patients.

• 4. The licensee shall comply with the provision of rules for safe disposal of radioactive waste.

• 5. The licensee shall:• i. Maintain records of workers.• ii. Arrange for preventive and remedial maintenance of radiation protection equipment,

and monitoring instruments.• iii. Investigate excessive radiation exposure and maintain records of such investigations.• iv. Inform competent authority about the occurrence, investigation and follow-up

actions, including steps to prevent future occurrences.• v. Carry out physical verification of radioactive material periodically and maintain

inventory.• vi. Inform appropriate law enforcement agency in the locality of any loss of source.• vii. Inform the employer and the competent authority of any loss of source.• viii. Investigate and inform the competent authority of any accident involving source and

maintain record of investigations.

• ix. Verify the performance of radiation monitoring systems, safety

interlocks, protective devices and any other safety systems in the radiation installation.• x. Prepare emergency plans in consultation with RSO.

• xi. Conduct quality assurance tests of structures, systems, components and sources and related equipment.

• xii. Advise the employer about the modifications in working condition of a pregnant worker.

• xiii. Inform the competent authority if the RSO or a worker leaves the employment.

• xiv. Inform the competent authority when he leaves the employment.

• 6. The licensee shall ensure that the workers are familiarized with contents of the relevant surveillance procedures, safety standards, safety codes, safety aides and safety manuals issued by the competent authority and emergency response plans.

RESPONSIBILITY OF RADIOLOGICAL SAFETY OFFICER(RULE 22)

• 1. Radiological Safety Officer (RSO) shall provide advice and assistance to the employer and licensee on radiation safety.

• 2. RSO shall:• i. Carry out measurements and analysis on radiation and radioactivity levels in the

controlled area, supervised area and maintain records of the same.• ii. Investigate any situation that could lead to potential exposures.• iii. Advise the employer to ensure regulatory constraints and the terms and conditions of

the license, safe storage and movement of radioactive material within the radiation installation, to initiate suitable remedial measures in any situation that leads to potential exposures, and regular measurements and analysis of radiation and radioactivity levels in and around the installation.

• iv. Report all hazardous situations with details and remedial actions taken, to the employer and licensee for reporting to the competent authority.

• v. Conduct quality assurance tests on structures, systems, components and sources.• vi. Ensure periodic calibration of monitoring instruments.• 3. RSO should assist the employer in

• (i) instructing the workers about hazards of radiation and safety and good work practices,

• (ii) safe disposal of radioactive wastes,

• (iii) developing emergency response plans to deal with accidents and maintaining emergency preparedness

• 4. RSO should advise the licensee on• • (i) modifications in working condition of a pregnant worker,

• (ii) the safety and security of radioactive sources.

• He should furnish to the licensee and the competent authority the periodic reports on safety status of the radiation installation.

• He should inform the competent authority, whenever he leaves the employment.

RESPONSIBILITIES OF WORKER (RULE 23)

• 1. Every worker shall observe safety requirements and follow safety procedures and instructions. He should not do any work that is harmful to him, co-workers, installation and public.

• 2. Worker should inform the employer about his previous occupations. He should use protective equipment, radiation monitors and personnel monitoring devices. He should inform the licensee and the RSO, about accident or any potentially hazardous situation.

• 3. Female worker, once become pregnant, she should inform the same to the licensee and Radiological Safety Officer

HEALTH SURVEILLANCE OF WORKERS (RULE 25)

• 1. Every employer shall provide the services of a physician with appropriate qualifications to undertake occupational health surveillance of classified workers.

• 2. Every worker, initially on employment, and classified worker, thereafter at least once in three years as long as the individual is employed, shall be subjected to the following: (a) general medical examination, and (b) health surveillance to decide on the fitness of each worker for the intended task.

• 3. The health surveillance shall include: (a) special tests or medical examinations as specified by order by the competent authority, for workers who have received dose in excess of regulatory constraints, and (b) counseling of pregnant workers.

PLANNING OF DIAGNOSTIC X-RAY INSTALLATIONS

GENERAL GUIDELINES

• Room Size• The room housing an X-ray unit shall be not less than 18 m2 for general

purpose radiography and conventional fluoroscopy equipment. • The size of the room housing the gantry of the CT unit shall not be less than 25 m2.• Also, not more than one unit of any type shall be installed in the same room, and no

single dimension of these X-ray rooms shall be less than 4 m. • In the case of mammography, the room size shall be not less than 10 m2, and no

single dimension of the room shall be less than 3 m.

WALL THICKNESS• If the X-ray installation is located in a residential complex, it shall be ensured that:• 1. Walls of the X-ray rooms on which primary X-ray beam falls are not less than 35 cm or

14 inch thick brick or equivalent.• 2. Walls of the X-ray room on which scattered X-ray fall are not less than 23 cm or 9 inch

thick brick or equivalent.• 3. There is a shielding equivalent to at least 23 cm or 9 inch thick brick or 2 mm lead in

front of the door(s) and windows of the X-ray room to protect the adjacent areas, either by general public or not under possession of the owner of the X-ray room. The density of the normal masonary brick is considered as 1.6 g/cc.

• 4. The ceiling must have a thickness of concrete (density 2.35 g/cc), not less than 6 inch or 13.5 cm.

OPTIONS IN SHIELDING MATERIALS

• X-ray equipment must be installed in adequately shielded rooms to ensure that public in the vicinity of the x-ray installations are not unduly exposed to x-ray radiation.

• The adequacy of shielding depends on the material and thickness used for this purpose. Different materials can be used for shielding.

• However, brick or concrete are considered the best materials, as they are easily available, economical, and have good structural strength

• While lead is a suitable shielding option for energies encountered in diagnostic x-rays, it is a weak structural material with tendency to lose uniformity and needs periodic radiation survey to ensure its continued adequacy.

• Also, Lead poses a serious environmental hazard and the use of it is being discouraged the world over. Recently, many new materials are being used/ developed as potential shielding materials, as an alternate to Lead.

• AERB would like to promote use of these materials, on demonstration of shielding adequacy

REFERENCE DATA ON SHIELDING OF X-RAY INSTALLATION ROOM

CONTROL ROOM• For equipment operating at 125 kV or above, should have a separate control room,

and provided with appropriate shielding, direct viewing (1.5 mm lead equivalence) and oral communication facilities between the operator and the patient.

• The X-ray units operating below 125 kVp in diagnostic radiology are exempted from the above class.

• In such a case, the control should be behind a mobile protective barrier of adequate thickness.

DOORS

• Doors are lined with 2 mm thick lead sheet with proper overlapping at the joint and junction and wall of 9 inch thickness of brick and ceiling of 6 inch of concrete

• Viewing Window• Lead glass of suitable dimensions are provided as viewing windows with 1.5

mm thick lead equivalent.• Mobile Protective Barrier• Control panel should be kept behind the mobile protective barrier (MBP) of

thickness 2 mm lead equivalence

PLACARD

GENERAL RADIOGRAPHY INSTALLATION• These X-ray units are operated in the range of 50–150 kVp.

• Walls that are irradiated directly by the X-ray beam are primary barriers.

• Hence, additional shielding must be provided for the wall behind the chest stand.• Provisions are made to observe and communicate with the patient on the table.

• The mobile protective barrier with lead shield must be a permanent/mobile one with 2.1 m height.

• The viewing window at the mobile protective barrier must be 45 × 45 cm size and centered

FLUOROSCOPY INSTALLATION

• Fluoroscopic imaging systems are usually operated at potentials ranging from 60 to 120 kVp.

• A primary barrier is incorporated into the fluoroscopic image receptor.

• Therefore, fluoroscopic unit room design considers only secondary protective barriers against leakage and scattered radiations.

• Most fluoroscopic X-ray imaging systems also employ radiography.

• The shielding requirements for such a room are based on the combined workload of both fluoroscopy and radiography

MAMMOGRAPHY INSTALLATION

• Mammography units are typically operated between 25–30 kVp.

• The walls are constructed with bricks or gypsum wall board.

• Adequate protective barrier of lead acrylic or lead glass are incorporated into dedicated mammography units.

• Gypsum wall board may contain voids and non uniform areas.

• Hence, higher thickness of gypsum wall board is recommended than that calculated.

COMPUTED TOMOGRAPHY INSTALLATION

• Computed tomography (CT) employs a collimated X-ray fan-beam that is intercepted by the patient and by the detector array.

• Consequently only secondary radiation is incident on protective barriers. • The operating potential, typically in the range of 80–140 kVp, as well as the workload

are much higher than for general radiography or fluoroscopy. • Due to large amount of secondary radiation, floors, walls and ceilings need special

consideration. • Additionally, scattered and leakage radiations from CT systems are not isotropic. • The radiation levels in the direction of the gantry are much less than the radiation levels

along the axis of the patient table.

GENERAL SAFETY RULES

• TUBE HOUSING• Leakage radiation through the protective tube housing in any direction, shall not

exceed an air kerma of 1 mGy in one hour at a distance of 1.0 m from the X-ray target when the tube is operating at the maximum rated kVp and for the maximum rated current at that kVp. There shall be a distinctly visible mark on the tube housing to indicate the plane of focus.

• Beam Limiting Devices• Tube housing for stationary and mobile diagnostic X-ray units shall be provided with

light beam collimators. These collimators shall comply with the leakage radiation level prescribed for tube housing

• Beam Filtration• (a) The minimum total filtration in useful beam for maximum rated operating tube

potential shall be as given in the following table:

• (b) Total filtration shall be indicated on the tube housing. The total permanent filtration in the tube shall be not less than 1.5 mm Al.

• Tube Positioning• X-ray unit shall have facilities for tube positioning, target-to-film distance selection, useful

beam centring and angulation, positioning of the patient and the X-ray film for exposure in the desired manner, and appropriate features to display the same.

• Bucky Alignment• X-ray table shall have provisions for correct positioning of the grid, the bucky tray and the

film cassette in proper alignment with the useful beam and for their locking in the desired position.

• Cable Length• X-ray unit shall be provided with electrical cables of sufficient length so that the control

panel/operation switch can be located and operated from a minimum distance of 3 m from the nearest position of the X-ray tube. For mobile/portable X-ray equipment the cable length shall be not less than 2 m.

• Control Panel• Control panel shall be provided with means to indicate and control exposure

parameters, including tube potential, time of exposure, tube current, and integral exposure in milliampere-seconds (mAs). It shall also provide facilities for technique selection and the engagement of the bucky mechanism. A clearly marked and identifiable indicator shall be provided at the control panel to show whether the X-ray beam is 'ON' or 'OFF'. For portable/mobile units appropriate indication of exposure parameters shall be provided.

• Tabletop• Tabletop should be made of radioparent substances which allow to pass

radiation without much attenuation. But as well as they should be strong enough to carry patient weight

• Carbon fibres are commonly used .

AERB GUIDELINES FOR DOSE LIMITS

DOSE LIMITS BY AERB

The limits on effective dose apply to the sum of effective doses from external as well as internal sources. The limits exclude the exposures due to natural background radiation and medical exposures.

Calendar year shall be used for all prescribed dose limits

Occupational exposures

1. An effective dose of 20 mSv/yr averaged over five consecutive years (calculated on a sliding scale of five years);

2. An effective dose of 30 mSv in any year;

3. An equivalent dose to the lens of the eye of 150 mSv in a year;

4. An equivalent dose to the extremities (hands and feet) of 500 mSv in a year and

5. An equivalent dose to the skin of 500 mSv in a year;

6. Limits given above apply to female workers also. However, once pregnancy is declared the equivalent dose limit to embryo/fetus shall be 1 mSv for the remainder of the pregnancy.

Apprentices and Trainees

The occupational exposure of apprentices and trainees between 16 and 18 years of age shall be so controlled that the following limits are not exceeded:

1. An effective dose of 6 mSv in a year;

2. An equivalent dose to the lens of the eye of 50 mSv in a year;

3. An equivalent dose to the extremities (hands and feet) of 150 mSv in a year and

4. An equivalent dose to the skin of 150 mSv in a year.

Dose Limits for Members of the Public

1. An effective dose of 1 mSv in a year;

2. An equivalent dose to the lens of the eye of 15 mSv in a year; and

3. An equivalent dose to the skin of 50 mSv in a year.

THANK YOU