Patent ID: 8905936

Claim:
A catheter positionable in a living body lumen to transmit and receive inspection waves at tissue in the living body lumen to form an image of the tissue, the catheter comprising: a catheter main body; a detector positioned in the catheter and configured to detect the inspection waves and output signals based on the inspection waves detected by the detector; the catheter main body possessing a distal end portion at which is located a window portion configured to permit the inspection waves to pass through to be detected by the detector, the detector being axially positionable in the catheter main body to detect the inspection waves passing through the window portion; a signal line connected to the detector to transmit the signals from the detector; a drive shaft positioned in the catheter main body and operatively connectable to an external drive apparatus to move the drive shaft rotationally and axially in a distal direction and a proximal direction, the drive shaft possessing a distal end to which the detector is fixed so that the detector moves axially and rotationally together with the drive shaft; a tube assembly comprising of at least one tube through which a proximal end of the drive shaft passes; and a bias member positioned radially outwardly of a tube of the tube assembly, wherein the bias member is configured to bias the drive shaft in the distal direction and further configured to automatically move the drive shaft towards the distal direction if the drive shaft is unintendedly moved in the proximal direction.