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Technical Specifications

silentscan_main.jpg (4535 bytes)The NEW Silent Scan™ 3000 Series systems offer an outstanding level of performance and features.  Choose the SS-3000 system for clinical practice, or the calibrated SS-3100 for fMRI applications.

MRI's are noisy.  Whether you run a clinical practice or do fMRI research, gradient noise is a problem that you and your patients have to deal with.  Higher field strengths and faster scans are only making problems worse.  And you need more than just an audio system to solve the problem.

Silent Scan™ Hearing Protection and Communication systems offer more than just music.  Designed specifically for MRI use, Silent Scan™ offers solutions for patient hearing protection, as well as solutions for patient communication.

And the technologist has not been forgotten.  An easy to use gooseneck microphone for communication; simple controls that make sense; and tough equipment that sets up quickly.  Silent Scan™ is a technologist's tool.

Silent ScanTM Benefits:

  • A Relaxed, Comfortable Environment for Your Patients
  • Superior Hearing Protection
  • Calibrated System Available for fMRI Use
  • Advanced 2-Way Communication for Technologists and Patients
  • Increased Successful Examinations
  • A Boost in Profitability
  • Easy Operation and Installation
  • A Limited One-Year Warranty
  • Extended Three-Year Warranty Available
  • Fully Compatible with the Silent VisionTM Visual System

Silent Scan's Guarantee
 Silent ScanTM is the most cost-effective hearing protection, music and communication system you can buy. Avotec uses the highest quality components to ensure performance. Silent Scan™ includes a one year limited warranty and offers an optional three year limited warranty. Use Avotec's installation service or call us about self-installation instructions.

Silent Scan™ the best in the world!   You owe your patients.  You owe yourselves.

 

SS-3000 Silent Scan™ Audio System

Patient Comfort is ... Hearing Protection
 head_coils.jpg (16376 bytes)Patient comfort starts with protection against gradient noise, the major complaint of MRI patients. Two different headsets means flexibility in hearing protection choices; the full coverage headset fits most head coils, while the stethoscopic headset can be used for very confining applications.

Patient hygiene is easy with disposable covers and eartips. The sanitary covers for the full coverage headset are easy to change, and the soft eartips for the stethoscopic headset mean increased patient comfort.  

The new Scan-Lock Plus™ connector and tubing assembly makes changing headsets a quick and simple operation. The mesh covered tubing prevents snags in the MRI bore, and protects the tubing.  The easy to clean surface is a great help with MRI hygiene.

All this leads to happier and more comfortable patients, which means less time lost and fewer incomplete scans for you.

Patient Comfort is ... Communication
Most MRI patients have great anxiety about their exams, and their ability to clearly communicate with you goes a long way towards relieving that stress. Silent Scan's TM specially designed headsets have a built-in microphone channel that allows crystal clear communication between you and your patients.  Patients will be clearly heard, regardless of their scan type or location within the bore. Yelling or repetition never occurs, because you and your patient will easily understand each other.

Real Friend audio headset™.  Having Mom, Dad or just a friend in the scan room is a great comfort to many patients during their MRI exam.  Adding the Real Friend accessory headset to your Silent Scan™ system allows that comforting friend to communicate with both the patient and the technologist.  Real Friend headset offers great hearing protection, and even better, your friend gets to enjoy the music too!  Real Friend; a way to make friends really count.

And if you are using one of Avotec's great visual systems, you should add Real Friend Video™ for the ultimate in patient comfort.

ss_tech.jpg (13845 bytes)Communication Console
The Silent Scan™ communication console has a flexible gooseneck microphone that is designed for the technologist's comfort. Since you no longer have to bend over to speak into an intercom, and the gooseneck microphone is always within easy reach, communication with your patients is effortless.

Patient Alarm System
For your very claustrophobic patients, Silent Scan™ has a built-in patient alarm system. The alarm consists of a simple, hand held rubber squeeze bulb, that when actuated by your patient, triggers an audible alarm at the communication console. Just the existence of the alarm can be comforting, and its ability to alert you to a panicky patient is a great aid to both parties.

Patient Comfort is ... Music 
The beneficial effects of music in reducing apprehension in MRI patients is well known. Music, when used as a comforting influence, can set the tone for the success of your patients' visits. The Silent Scan TM headset allows your patient to relax to the music - free from gradient noise. Careful matching of transducer characteristics and filter design in the Silent Scan™ system provides a remarkably clear music signal for the wearer of the headset. Because the headsets offer genuine hearing protection, the highest quality sound can be enjoyed at a comfortable listening level.

Patient Comfort is ... User-Friendly Equipment 
Equipment that is easy to operate gives you more time to devote to your patients. All elements of the Silent Scan TM system have been constructed for ease of use. The Silent Scan™ console has only five controls, and in routine operation, only two of these controls are needed. The communication console has been thoughtfully crafted for easy operation, reliability, and long term comfort for you and your patients.

fMRI or SS-3100 Silent Scan™ Audio System

Successful audio stimulation for fMRI is a tough task because of the high ambient noise levels from the gradients.  Good signal to noise ratio (SNR) for stimulation needs effective noise reduction for the patient, as well as an adequate acoustic output to handle the variations in subject hearing loss.  The SS-3100 has been specifically designed for fMRI use.

The SS-3100 is based on the SS-3000 audio system.  The SS-3100 adds the following features to the SS-3000:

  • Flat frequency response, so you get uniform audio output.

  • Calibration, so you know what sound pressure level is delivered to the patient.

  • High audio signal levels (120dBA).

  • Test tone output provides a 90dBA reference tone.

  • Gain selection for audio input to compensate for sound card outputs.

  • Digital inputs.

Flat Frequency Response
The SS-3100 is supplied with a two-channel, one-third octave (OTO) band equalizer.  The equalizer is set to provide flat (+/- 5db) audio output across the nominal bandwidth of the audio system (150-4500Hz).

Calibration
The acoustic calibration of the SS-3100 audio system consists of feeding a known electrical input signal to the audio system input and making a direct acoustic output measurement at the headset of the audio system.

Measurement Details

The test input signals consists of:

  1. White noise (flat spectrum) input for filter adjustments and phase delay.

  2. Sinosoidal tones for sensitivity measurements.

  3. Impulse input for impulse response and time delay.

The pertinent acoustic portions of the Silent Scan™ audio system consist of the electrical input to the transducer, the transducer output, the coupling of the transducer output to the headset via the tubing assembly, and the coupling of the tubing acoustic output to the patient's ears.

We use the electrical input to the transducer for our time/phase delay measurements (as opposed to trying to measure the near field response of the transducer).  We use a representative tubing assembly (10 feet) to model the coupling of the transducer output to the headset.

We measure the sound pressure output of the tubing assembly by using a 2cc coupler to connect the tubing assembly to the measurement microphone.  The construction of the coupler is as described in IEC 126 (1961) and the coupler is used as described in ANSI S3.3-1971 (R-1960).  The sound level meter is a BK 2230, Type I classification.  All sound pressure level measurements derive from this instrument.  The output of the sound level meter is fed to a spectrum analyzer as necessary for analysis.

High Audio Output
As can be seen from the calibration data, the SS-3100 can achieve sound pressure levels (SPL) on the order of 120 dBA.  High SPLs, under controlled and monitored fMRI experiments, can be useful in two ways.

First, high SPLs may be necessary for effective stimulation of hearing impaired subjects.

Second, the stimulus SNR may be increased by utilizing the additional SPL dynamic range of the SS-3100.  SNR is increased by using secondary hearing protection means (such as earplugs) to reduce the ambient (gradient) noise heard by the subject; the concomitant decrease in stimulus SPL can be overcome simply by increasing the SPL output of the SS-3100.

Test Tone
The SS-3100 can output a fixed 1 kHz tone at a nominal 90 dBA sound pressure level.  This can be used as a useful reference signal.

Gain Selection
Sound cards that are used in may fMRI applications (particularly laptop based systems) do not have adequate signal levels to drive the SS-3100 audio system to its full capabilities.  The necessary signal levels are on the order of 1Vrms.  The SS-3100 has an output setting with a 10dB gain to compensate for this.

Digital Inputs
The SS-3100 accepts a fiber optic SPDIF input.

Technical Specifications SS-3000/3100

Music / Audio Inputs
 Silent Scan TM accepts music input from any high quality stereo system with CD, cassette and AM / FM sources. Computer generated inputs may also be used for functional MRI studies.

Silent VisionTM
Silent ScanTM is fully compatible with Avotec's Silent VisionTM fiber optic visual presentation system for fMRI, MRI and MEG.

OEM
Avotec offers full design and manufacturing capabilities for MRI related accessories. We invite your inquiry.

Components
Communication console with gooseneck microphone, transducer/electronics housing, cabling and connectors between console and housing, two types of patients headsets, one ten foot Scan-LockTM tubing assembly, patient alarm system with rubber squeeze bulb and ten feet of plastic tubing, and stereo interface box.

Physical
Console, 7"H x 5"W x 8"D, 3 lbs.; Gooseneck Microphone, 17"; Transducer Housing, 4"H x 6"W x 3"D, 13 oz.; Transducer Cable, 200 feet (max); Stethoscopic Headset with silicon rubber eartips, 0.7 oz.; Full Coverage Headset, 13 oz.; 10 Foot Tubing Assembly, 19 oz.; Stereo Interface Box, 2.5"H x 2.5"W x 2"D, 4 oz.; Stereo Interface Cable, 15 feet.

Electrical
110V AC, 1Amp, fused; 220V AC version available.

Cabling
Transducer and Cable Interface Cables, 4 shielded twisted pairs; Power Cord, 3-wire grounded, 9 feet.

Colors
Housings: pearl white; Cables: gray.

Specifications subject to change without notice.

Avotec, Inc.
603 N. W. Buck Hendry Way
Stuart, FL  USA 34994
Telephone (772) 692-0750    Fax (772) 692-0788
avotec@avotecinc.com
www.avotecinc.com

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