The IMROC Communications system is based on optical technology, where no electrical
signals are present in the MR room, thus eliminating any possibility for RF
noise and interference.
The IMROC system comprises of the following main sub-assemblies:
- Headsets, each includes two high fidelity optical speakers
- Each headset includes FOMRI – a dual-channel highly directional
noise canceling microphone which utilizes a tailor-made DSP unit that filters
out the MR noise as received in the microphone
- Optical Switching unit, on the Doctor’s belt, with thin rigid tubes
which include fibers going in and out
- The mixer in the control room which includes electronics, optics, headsets
and loudspeaker
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General System Information
1. The IMROC system provides duplex communication between staff members during
interventional MRI procedure, with concurrent duplex communication between
staff and patient.
2. The system includes three communication channels as follow:
- Staff Channel
- Patient Channel
- Staff and Patient channel.
3. The system comprises of the following components:
- Staff Headset (X5)
- Staff Switch Box (X5)
- Patient Headset (X1)
- Patient Switch Box (X1)
- Control Room Console (X1) + loudspeaker + 2 headsets (including microphone)
Audio quality main highlights
- The system includes high noise suppression on speech and noise, which is received at the microphone. A VOX system is also included which uses the high SNR advantage so the ‘Push to Talk’ button is not necessary
- The system does not include microphone volume control for two reasons (1) it is better to control the volume of received speech by loudspeaker volume control (2) as this is highly directional microphone, if speech signal is too high, the microphone can be positioned away from mouth (a few inches away will decrease volume of microphone to almost zero)
- The system includes an ‘anti-feedback’ circuit to significantly minimize the effect of high pitch feedback noise when headsets are adjacent to each other
- The system has no ‘hiss' or any electronic/RF noise
- The control room includes to high fidelity headsets and loudspeaker. Music or any MP3 sources can be played back and connected to the console mixer
- Optical speaker produces high fidelity of audio up to 110 dB, with frequency range of 100 Hz to 10 kHz, optimized for maximum intelligibility.
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System Block Diagram
In this case, all headsets will be identical (including the patient headset)
as all are entirely passive and do not affect MR imaging. They are all MR safe.
Figure 1.
System architecture for duplex communication system. All headsets
will be based on passive optical speaker and optical microphone. Switching
will be done optically rather than electrically.
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03-IMROC |
IMROC - Interventional Magnetic Resonance Optical Communications System |
