PCT No. PCT/IL96/00006 Sec. 371 Date Jul. 9, 1998 Sec. 102(e) Date Jul. 9, 1998 PCT Filed Jun. 6, 1996 PCT Pub. No. WO96/41566 PCT Pub. Date Dec. 27, 1996There is described a new sensor for optical blood oximetry as well as a method and apparatus in which the new sensor is used. The new sensor includes two point-like light emitters (23,24) positioned in the center of the device in close proximity to each other and at least one and preferably two annular detector terminals (32,39) concentrically surrounding the light emitters. The light sources may, for example, be two laser diodes emitting each monochromatic light within the range of 670 nm to 940 nm. The detector devices are, for example, photodetectors.