MRI Space Planning

MRI Space Planning

1. MRI Rooms Space Planning

Room	Technical Finished-Room Size	Technical Finished-Room High
Control room	min. 150 x 190 cm	min. 210 cm
Equipment room	min. 230 x 165 cm	min. 220 cm
Examination Room     •  Full Body        Mobile patient table	min. 351 x 662 cm	min. 240 cm

2. Area requirements and floor loading for the magnet  

The system has to be installed on a solid underground with sufficient carrying capacity,

such as, e.g. concrete. The load bearing capacity has to be checked by a stress analyst.

The floor in the vicinity of the magnet must be levelled to within max. ± 2 mm.

External vibration or shocks affecting the magnet may degrade image quality. In the 3 spatial orientations the building vibration must not exceed the following specification:

 

2.1 Building vibration specification:

a _max = - 80 dB(g) in the frequency range from 0 to 100Hz.

The requirement for a _max is frequency dependent.

3. Weights to be consider

 

Magnet:	As per Manufacturer,~  5500 kg
Patient table:	~250kg
Electronic cabinets	~1850 kg
UPS to support the MRI system	~2500 kg
Iron Shielding	As per static calculation
RF Cabin	Depends on the material and size

4. MRI Environmental Requirements

MRI	Examination room	Equipment room	Control room/ Evaluation
Room temperature   Temperature gradient	18 to 22 °C   n.a.	15 to 30 °C   </= 1.0 K/5min	15 to 30 °C   n.a.
Relative humidity	40 to 60 %	40 to 80 %	40 to 60 %
Absolute humidity	< 11 g / kg	< 11 g / kg	< 11 g / kg

5. Room lighting in the MRI room

 

The magnetic field adversely affects the operating life of light bulb located in the

immediate vicinity of the magnet. The filament in the light bulb oscillates with the frequency of the power supply.

It is therefore recommended to connect light fixtures in the vicinity of the magnet to

a DC voltage supply. If room lighting is supplied with DC voltage, correct polarity of
the sockets should be ensured during their installation.
Residual AC ripple should be £ 5 %.

Fluorescent lighting must not be installed inside the examination room. Only lamps without phase angle control should be used. Do not use energy-saving lamps.

6. Noise Emission

If required, noise reduction should be realized based on the noise emission values as specified.

MRI	Examination room	Control room	Equipment room
Average values across 8 hours	≤ 80 dB(A)	≤ 54 dB(A)	≤ 67 dB(A)

 

7. RF Shielding

An RF shielding (Faraday cage) is required for the MR examination room. This shielding

protects the environment from RF interference and conversely protects the MR system

from external interference.

 

Required attenuation: >90 (Co-siting 100) dB over the frequency range 15 to 128 MHz.

These values must be verified by measurement before the MR system is installed.

RF shielding components (doors, windows, interfaces) and complete modular RF cabins

can be supplied from different sources.

 

8. Quench Pipe

A quench pipe (thermally insulated tube) made of non-magnetic metal must be fitted

from the super-conducting magnet to the outside of the building in order to vent the
vaporising helium gas.

9. Magnetic field level warning signs in the control zone ³ 0.5 mT

If the magnetic flux density in a given area exceeds 0.5 mT, it is necessary to display

warning signs and restrict access in accordance with local regulations.

 

10. Water connection

Either you connect a chiller recommended by the MRI manufacturer or you can connect it to hospital chiller system.

11. Power Supply:

The Superconductive magnet normally required  3Phase/N/PE, AC 380V, Connections Value ~120 KVA.

12. Guidelines for max. permissible flux density  (mT)

Max. permissible flux density		mT
Servoventilator, Defibrillator		20
Filter		10
Small motors, watches, photographic equipment, magnetic data storage devices (short term)		3
Computers, disc drivers, oscilloscopes, host PC, imager PC		1
B/W monitors, X-ray tubes, storage of magnetic data carriers, cardiac pacemakers, insulin pumps. (safety limit for unrestricted open access)		0.5
CT-systems		0.2
Colour monitors (CRT)		0.15
Linear accelerators		0.1
Image intensifiers, gamma cameras linear accelerators		0.05
Laser cameras / digital cameras	see manual of the manufacturer

The magnetic stray field is present in all three dimensions around the magnet and can
be reduced by a magnetic shielding. Typical lines of constant magnetic flux density are
shown in the drawing.