Apparatus for measuring blood flow

An apparatus for measuring a blood flow, comprising:

• a scanning optical system having optical components for guiding a coherent light beam to impinge on a stationary measurement spot of a measurement plane of an in vivo tissue;
• a light receiving optical system for focusing a light image of the measurement plane in the vicinity of an image point conjugate with the stationary measurement spot, the light image having an optical axis, and the light receiving optical system sharing at least a part of the optical components of the scanning optical system;
• at least one photodetecting means disposed at prescribed positions perpendicular to the optical axis and in the vicinity of the image point for measuring light scattered from the in vivo tissue to provide blood flow information related to blood flowing at a depth within the in vivo tissue;
• video imaging means for receiving a visible image of the measurement plane and converting it into a video image;
• and
• image superimposing means for superimposing blood flow information corresponding to the position of the stationary measurement spot on the video image and displaying the superimposed blood flow information and video image as a composite visible image.