Abstract: A medical device position guidance system having a noninvasive medical device communicable with an invasive medical device. The system provides outputs useful to assess the position of an invasive medical device in an animal, such as a human. A magnetic field is used to gather information about the position of the invasive device. Radio waves are used to communicate this information between the noninvasive device and the invasive device.

Abstract: A medical device position guidance system having a noninvasive medical device communicable with an invasive medical device. The system provides outputs useful to assess the position of an invasive medical device in an animal, such as a human. A magnetic field is used to gather information about the position of the invasive device. Radio waves are used to communicate this information between the noninvasive device and the invasive device.

Abstract: A medical device position guidance system having a noninvasive medical device communicable with an invasive medical device. The system provides outputs useful to assess the position of an invasive medical device in an animal, such as a human. A magnetic field is used to gather information about the position of the invasive device. Radio waves are used to communicate this information between the noninvasive device and the invasive device.

Abstract: A medical device position guidance system having a noninvasive medical device communicable with an invasive medical device. The system provides outputs useful to assess the position of an invasive medical device in an animal, such as a human. A magnetic field is used to gather information about the position of the invasive device. Radio waves are used to communicate this information between the noninvasive device and the invasive device.

Abstract: A system for externally locating a sensor in tissue, comprising an external probe including at least first and second electromagnetic output coils with non-parallel longitudinal axes; and output coil driver for alternately energizing the first and second output coils, for generating a time-varying magnetic field which penetrates the patient's skin; a sensor coil, having a longitudinal axis, for developing an induced electrical voltage in response to the time-varying magnetic field; a distance determinator, responsive to the induced voltage from the sensor coil, for determining from the induced voltage, the distance between the output coils and the sensor coil, independently of the relative angle, in a horizontal plane, between the sensor coil longitudinal axis, and the longitudinal axes of the output coils; and a direction determinator for determining and displaying the direction, in the horizontal plane, in which the sensor coil longitudinal axis is pointing.

Abstract: A system for externally locating the depth and orientation of a catheter in tissue with an external probe which generates a virtual rotating magnetic field. The catheter includes an inductive coil for developing an induced signal in response to the virtual rotating magnetic field. An indicating device such as a light bar display or digital readout indicates the strength of the induced signal for locating, independently of the relative angular orientation of the probe and the catheter, the depth in the tissue of the catheter.

Abstract: Disclosed is a method for imparting to a living culture of cells biaxial mechanical forces which approximate the mechanical forces to which cells are subject in vivo. The method utilizes a displacement applicator which may be actuated to contact and stretch a membrane having a living cell culture mounted thereon. Stretching of the membrane imparts biaxial mechanical forces to the cells. These forces may be uniformly applied to the cells, or they may be selectively nonuniformly applied.

Abstract: Disclosed is an apparatus and method for imparting to a living culture of cells biaxial mechanical forces which approximate the mechanical forces to which cells are subjected in vivo. The apparatus includes a displacement applicator which may be actuated to contact and stretch a membrane having a living cell culture mounted thereon. Stretching of the membrane imparts biaxial mechanical forces to the cells. These forces may be uniformly applied to the cells, or they may be selectively non-uniformly applied.

Abstract: A method and apparatus (10) for determining accurately the location of the tip (14) of a catheter (16) inside biological tissue is disclosed including a locator (34) having a coil (38) wound axially on a core (36) and a detector (12) in the form of a coil (28) wound on a core (24) removably positionable within catheter (16) adjacent the tip (14). A controller (20) generates AC current to coil (38) to produce an electromagnetic field and compares it with the output voltage developed in coil ( b 28) when the locator (34) comes within close physical proximity to detecetor (12). Locator (34) includes an amber LED indicator (42) which is energized when the locator (34) is behind the detector (12) and the monitored output voltage is in phase with the generated alternating current and includes a red LED indicator (44) which is energized when the locator (34) is beyond the detector (12) and the monitored output voltage is 180.degree. out of phase with the generated alternating current.

Abstract: Automatic test equipment for determining the optical properties of a test object is described. A highly collimated test beam of approximately one millimeter diameter is directed through the test object, is reflected, and passes through the test object a second time. The test beam source may be a laser and spatial filter, or equivalent. The reflected beam intensity and the exit point and return slope angle at which this beam leaves the test object are accurately measured to determine the optical characteristics of the test object. In one described embodiment, the exit point is determined by moving a knife edge to a point where half the light is blocked. The angle is determined by focusing the reflected beam and determining the position of the focal point, i.e. image height, by means of a pinhole mounted on a three axis micrometer platform. The light transmitted through the pinhole is detected by a light sensitive diode or equivalent.