Optical coherent cross-sectional image forming apparatus and control method for controlling such apparatus

An optical coherent cross-sectional image forming apparatus in which light outputted from a light source is divided into a measurement light and a reference light inside the apparatus and in which a cross-sectional image is formed based on a coherent light obtained from reflected light, acquired when the measurement light emitted toward a biological tissue through a probe inserted into a body lumen is reflected, and the reference light, the apparatus comprising:

• an optical fiber connected to the light source, the optical fiber possessing a distal end portion which transmits the measurement light and also receives the reflected light;
• the optical fiber being positioned inside a catheter sheath, the optical fiber being rotatable within the catheter sheath, the optical fiber also being axially movable within the guiding catheter to axially move the optical fiber;
• a scanning drive unit connected to the optical fiber to rotate and axially move the optical fiber relative to the catheter sheath to axially move the distal and portion of the optical fiber into the catheter sheath;
• generating and holding means for generating and then holding data which is based on the coherent light and which is used to produce the cross-sectional image;
• means for determining that the distal end portion of the optical fiber which transmits the measurement light and also receives the reflected light has moved from a position outside the catheter sheath to a position inside the catheter sheath so that the distal end portion of the optical fiber is inside the catheter sheath;
• and
• control means for stopping at least one of the generation of the data and the holding of the data whenever the means for determining determines that the distal end portion of the optical fiber which transmits the measurement light and also receives the reflected light has entered the catheter sheath.

A method for controlling an optical coherent cross-sectional image forming apparatus in which light outputted from a light source is divided into a measurement light and a reference light inside the apparatus and in which a cross-sectional image is formed based on a coherent light obtained from reflected light, acquired when the measurement light emitted toward a biological tissue through a probe inserted into a body lumen is reflected, and the reference light, the method comprising:

• rotating and axially moving a transmitting and receiving unit at a distal end portion of the probe which emits the measurement light and receives the reflected light, the transmitting and receiving unit being axially moved relative to a guiding catheter;
• generating data corresponding to the cross-sectional image using the coherent light and holding the data in a memory unit;
• determining when the transmitting and receiving unit has entered inside the guiding catheter during the axial movement of the transmitting and receiving unit;
• and
• stopping at least a portion of an operational aspect of the apparatus occurring between the generation of the data and the holding of the data whenever it is determined that the transmitting and receiving unit has entered inside the guiding catheter.