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Patient Position and Speed Detection System in High Magnetic Field using Flight of Light Time

IP.com Disclosure Number: IPCOM000012473D
Publication Date: 2003-May-08
Document File: 1 page(s) / 68K

Publishing Venue

The IP.com Prior Art Database

Abstract

Typical position finding devices, such as encoders, do not work under a high magnetic field within a 7T magnet room. There is a need to find an alternate system, which will give cradle/patient location. A short electrical pulse drives a semiconductor laser diode to emit a pulse of light in the device. The emitted light is collimated through a lens, which produces a very narrow laser beam. The time interval between the two electrical pulses (transmitting and receiving the beam) is used to calculate the distance to the target, using the speed of light as a constant. Due to the fact that 1) most of the components are non-ferrous or even non-metallic and 2) the working principle not being dependent on any moving parts like an encoder, the system works in the high magnetic field of a 7T magnet.

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FIELD OF TECHNOLOGY: 

Magnetic Resonance Imaging (MRI)

INVENTION TITLE: 

Patient Position and Speed Detection System in High Magnetic Field using Flight of Light Time

PROBLEM/BACKGROUND: 

Typical position finding devices, such as encoders, do not work under a high magnetic field within a 7T magnet room. The speed at which a person is moved into the 7T field affects his/her tendency to vomit uncontrollably. There is a need to find an alternate system, which will give cradle/patient location.

INVENTION DESCRIPTION: 

A short electrical pulse drives a semiconductor laser diode to emit a pulse of light in the device. The emitted light is collimated through a lens, which produces a very narrow laser beam. The laser beam bounces off the target, scattering some of its light through the sensor’s receiving lens to a photodiode, which creates an electrical pulse. The time interval between the two electrical pulses (transmitting and receiving the beam) is used to calculate the distance to the target, using the speed of light as a constant. Multiple pulses are evaluated by the sensor’s microprocessor, which calculates the appropriate output value. The analog output provides a 4 to 20 mA variable signal that is proportional to the target’s position within the limits of the user-programmed analog window.

Due to the fact that 1) most of the components are non-ferrous or even non-metallic and 2) the working principle not being dependent on any moving parts like an encoder, the system works in the high magnetic field of a 7T magnet.

ADVANTAGES OF THE INVENTION:

Currently, this is the only system ca...