Room Design

Radiography room design

Introduction

The location, structural design and equipment layout of X‑ray rooms must be carefully considered from a radiation protection perspective.

The practical requirements for radiation protection depend on the type of X ray equipment, usage, as well as the workload and adjacent occupancy.

Radiography room design ensures radiation safety for patients, staff, visitors, and the public.

Equipment

• What equipment is to be used?
• General radiography
• Fluoroscopy (with or without radiography)
• Dental (oral, cephalometric, or OPG)
• Mammography

CT

The type of equipment is very important for the following reasons:

• where the X Ray beam will be directed
• the number and type of procedures performed
• the location of the radiographer (operator)

the energy (kVp) of the X Rays

Usage

Different X Ray equipment have very different usage.

For example, a dental unit uses low mAs and low (~70) kVp, and takes relatively few X Rays each week A CT scanner uses high (~130) kVp, high mAs, and takes very many scans each week.

Surrounding areas

The X Ray room must be designed with knowledge of the location and use of all rooms which adjoin the X Ray room Obviously a toilet will need less shielding than an office Obtain a plan of the X Ray room and surroundings (including level above and below)

Remember we must shield against three sources of radiation

• In decreasing importance, these are:
• scattered radiation (from the patient)
• primary radiation (the X Ray beam)

leakage radiation (from the X Ray tube) Use a reasonable, worst case scenario (conservatively high estimates), since under-shielding is worse than over-shielding Anything which separates one area from another is called a barrier. Any barrier which may be in the direct X Ray beam is called a primary barrier. If the X Ray beam will never be directed towards a barrier, it is called a secondary barrier. In practice, some barriers will have the primary beam directed at them part of the time only, and the rest of the time they will be a secondary barrier. This must be taken into account in the calculations.

Walls

The walls shall be constructed using concrete blocks with density of 2.35g/cm3 of at least 30 cm thickness;

Lead-Shielding equivalent to atleast 1mm lead Protection needs to extend from the floor to a height of not less than 2m and be continuous.

• Paint -Smooth (washable paint or easy clean-up)
• Color –cool color

Note ; shielding must be calculated by a physicist or radiation expert

Floor

• Material used is Vinyl floor
• Vinyl Conductivity-Non-conductive, which is safer around electrical equipment.
• Absorb rays
• Fire resistant
• Slip resistant
• Shiny
• Easily cleaned
• The flooring should be able to bear a load of heavy machines.

Shielding equivalent atleast 1mm lead

Ceiling

Concrete is basic construction material used in floors and ceilings.

The radiation attenuation effectiveness of a concrete barrier depends on its thickness, density and composition. using an average density concrete of 2.35gcm-3, a thickness of atleast 150mm and 100mm is ideal for ceiling and for floor respectively. The minimum ceiling height should be 2.5m.

Control room

There should be a control cubicle/room constructed by using concrete blocks 30 cm thick with a wall height of at least 2.4 m from the floor to the ceiling;

The cubicle should have a patient viewing window of a size of at least 60 cm x 70 cm. The viewing window should be installed with a radiation shielding glass (lead glass) preferably of 2.7 mmPb/150 kV thickness or 2.1mmPb/110kV. The lower margin of the window should be at 120 cm from the floor;

The control room has to be of adequate size to accommodate computers, image reader(s), printer(s) and personnel.

Doors

All doors leading to examination room should be shielded with at least 2 mm of lead sheet or 4 mm iron sheet and overlap of atleast 10 cm each side of the door The door(s) leading to the X-ray room are shielded to ensure that radiation leakage through the shutters and frames of the door(s) do not exceed 0.5 μSv/hr;

All door should have handles and locks on the inside and the outside so that they may always be closed during exposures thus controlling access.

Labeling and Warning signs

The public and workers should be aware of the presence of radiation in any room. Therefore, standard radiation warning signs and notices at all entrances with a standard radiation sign must be displayed.

The labelling or notices shall be in English and any other language.

The redlight showing x-ray machine is in use must be installed at the top of each door leading to the x-ray room.

Windows

The windows are avoided to reduce the penetration of radiation in the surrounding area.

Windows are not preferred in the x-ray room, but if there are installed they must be atleast 2.4m above the floor from the outside and access must be prevented Air conditioning machine is advised for cooling purposes of the X-ray machine.

X-ray Machine installment

The x-ray machines must be installed in the corner so that there is enough moving space Any x-ray equipment must be installed adequately shielded rooms to ensure that workers and the public in the vicinity oof the x-ray installation are not unduly exposed to x-ray radiation.

Exposure button; remain atleast 6 feet( 2 meters) away from an x-ray radiation source.

General recommendations for the design of a radiology room

The equipment should be positioned so that the primary radiation beam is not directed at the operator’s console, windows or doors.

Particular attention must be paid to the shielding of areas where the primary beam will be directed The floor of the X‑ray room must be shielded for the primary radiation beam if there is occupancy in the room below and the beam is not otherwise attenuated.

Room Design

The operator’s console area should be located so that: it is adjacent to the staff entrance door; the operator has a clear panoramic view of the patient and the access doors to the room; and radiation is scattered at least twice before entering the protective area The protective screen should be at least 2 m in height and of sufficient width to allow at least two people stand behind the screen during an exposure.

Personal protective equipment (lead aprons, thyroid shields, gonad shields) should be available and reinforced hangers should be used for the storage of lead aprons.

Room Design

Multilingual pregnancy signs should be displayed in the waiting room and patient cubicles, advising female patients to declare their known or suspected pregnancy prior to undergoing a radiological examination.

Radiation warning lights should be positioned at all access doors to the room. The light should illuminate during the preparation period (if applicable) and continue for the duration of the exposure Appropriately worded radiation warning signs must be posted on access doors to the room.

Room Design

The room layout and shielding design must be reviewed by the Radiation Protection officer each time the equipment or technology changes.

An X‑ray room should not be used for more than one radiological procedure at a time, unless specifically designed for this purpose The X‑ray room should not be a throughway to another room.

The design of ancillary facilities such as changing cubicles, toilets and preparation rooms should be considered.

Questions

• What are is the lead equivalent and thickness require for;
• Walls
• Floors
• Ceiling
• Mention atleast 2 warning signs requirement for radiation rooms

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