Sensing apparatus and methods

Apparatus according to any preceding claim in which the transmission and detection means are capable both of being moved along the exogenous conduit and of being rotated within the exogenous conduit about a longitudinal axis of the exogenous conduit.

Apparatus according to any preceding claim in which the determining means compares the returned signals on the basis of at least one of their energy and frequency.

Apparatus according to any preceding claim in which the transmitted signal is an ultrasonic signal.

Apparatus according to any preceding claim in which there are provided two paths for conveying signals between the sensing and processing means.

Apparatus according to any preceding claim in which the sensing means comprises at least one piezoelectric transducer.

Apparatus according to any preceding claim in which the sensing means comprises dual transmission and detection transducers with a known, fixed angle between their signal paths.

Apparatus according to any preceding claim in which the means for passing the sensing means along the exogenous conduit comprises a flexible cable which, in use, is capable of being rotated about its longitudinal axis without developing substantial elastic twisting forces.

Apparatus according to any preceding claim in which the remote control of the sensor position within the exogenous conduit is achieved by means of a rotatable knob connected to the extracorporeal end of the passing means.

Apparatus according to any preceding claim in which the exogenous conduit is a nasogastric tube.

A method of remotely locating biological material interfaces, the method comprising transmitting a signal into the biological material using an apparatus according to any preceding claim with its sensing means located in an exogenous conduit placed within a bodily tract with access to the extracorporeal environment, detecting the signals returned from at least one pair of locations along the path of the transmitted signal and determining from the returned signals wither there is an interface between each pair of locations.

A method of remotely aligning a sensor relative to a biological vessel, the method comprising providing a sensor capable of being passed, using passing means, along an exogenous conduit placed within a bodily tract with access to the extracorporeal environment and which sensor transmits a signal along a path, remotely positioning the sensor such that the path intersects the biological vessel, detecting the signals returned from the biological vessel and determining from the returned signals whether the path intersects substantially the center of the biological vessel.