Patent ID: 8094319

Claim:
An image diagnostic apparatus comprising: a light source; a probe connected to the light source to transmit light from the light source and receive reflection light in a body cavity by rotatingly scanning the probe in the body cavity to permit formation of a tomographic image in the body cavity based on the reflection light; a first branch portion for branching the light transmitted to the probe; a sample light path branched on the sample side by the first branch portion; a reference light path branched on the reference side by the first branch portion; a light transmission permitting and preventing device positioned along the sample light path, the light transmission permitting and preventing device possessing an incident port and an emission port; a control unit connected to the light transmission permitting and preventing device for controlling the light transmission permitting and preventing device to either permit the light at the incident port to exit out of the emission port or to prevent light at the incident port from exiting out of the emission port; the light transmission permitting and preventing device comprising one of: a shutter unit in which a movable shutter is positioned in a housing and is controlled by the control unit to move between one position permitting the light at the incident port to exit out of the emission port and another position preventing light at the incident port from exiting out of the emission port; and a frequency shifter unit controlled by the control unit to shift a frequency of light at the input port to either permit or prevent the light at the inlet port to exit the frequency shifter at the emission port; and a connection detector which detects connection of the probe, the control unit controlling the light transmission permitting and preventing device based on information from the connection detector.