Electro-optical isolator for magnetic resonance tomography

• US 4,763,075 A
• Filed: 07/19/1985
• Issued: 08/09/1988
• Est. Priority Date: 08/20/1984
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Weigert, Kurt
• Primary Examiner(s): Tokar, Michael J.
• Application Number:
  US06/756,883
• Time in Patent Office: 1,117 Days
• Field of Search: 324/318, 324/300, 324/307, 324/309, 324/314, 324/304, 324/305, 324/322, 324/95, 324/96, 324/72, 128/653, 128/696, 128/709, 128/716, 378/95, 455/602, 455/612, 250/551
• US Class Current: 324/318
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/301 providing electrical separation, e.g. by using isolating transformers or optocouplers
• CPC Class Codes: A61B 5/7285 for synchronising or triggering a physiological measurement or image acquisition with a physiological event or waveform, e.g. an ECG signal A61B6/5205, A61B6/541, A61B8/5207, A61B8/543 take precedence
• CPC Class Codes: G01R 33/28 Details of apparatus provided for in groups G01R33/44 - G01R33/64
• CPC Class Codes: G01R 33/5673 Gating or triggering based on a physiological signal other than an MR signal, e.g. ECG gating or motion monitoring using optical systems for monitoring the motion of a fiducial marker

Abstract

The invention relates to equipment for magnetic resonance tomography where, for the formation of physiological test signals, an electronic measuring system with an electro-optical transducer is arranged in a shielded cabin receiving the magnetic resonance tomograph. From this transducer a beam waveguide leads to an electronic processor with an opto-electric transducer provided outside the cabin. At the input, the electronic measuring system comprises a radio-frequency filter, a following wideband amplifier and thereafter, before the electro-optical transducer, a slew rate filter.

Claims

1. Apparatus for use with magnetic resonance tomography equipment to gate the imaging process without excessive electrical interference from gradient pulses and like electrical signals, wherein at least a part of said magnetic resonance tomography equipment is located inside a shielded region, comprising:

an electronic measuring system located inside said region and responding to a one of a patient'"'"'s body functions to produce an electrical signal suitable for gating, said system comprising a slew rate filter;

an electro-optical transducer located inside said region and converting said electrical signal to an optical signal;

as waveguide coupled to the electro-optical transducer and transmitting said optical signal outside said region; and

an opto-electrical transducer located outside said region and coupled to said waveguide, said opto-electrical transducer converting said optical signal to an electrical output signal.

2. The apparatus of claim 1, wherein the electro-optical transducer produces an analog optical signal.

3. The apparatus of claim 1, wherein the electronic measuring system further comprises an RF-filter at its input and a wideband amplifier connected to the RF-filter, and the slew rate filter is connected between the wideband amplifier and the electro-optical transducer.