A camera-type diameter gauge applicable to small blood and lymph vessels.

A camera-type diameter gauge was constructed and used in physiological experiments. The distinctive features of the design and use of the gauge may be summarized as follows. Installation of an image sensor in the focal plane of a single-lens reflex camera equipped with a set of extension tubes which makes it possible to measure outer diameters of blood and lymph vessels as small as 100 micrometer. Using the gauge, we can distinguish a diameter change of about 12 micrometer. Simultaneous measurements of the diameters of two different vessels can be made using two window signals generated independently at desired moments for appropriate periods within the video scans.