Abstract: Apparatus and method for determining the position of a vein or artery in a member of a living being. With an IR light source, more particular an IR led light source, the related member such as an extremity and more particular a hand, is trans-illuminated. The IR light emerging from the member is scanned with a camera and the image is produced on a display adjacent to the camera. Camera and display are preferably mounted on a manoeuvrable arm which can be placed in any desired position relative to the member and observer. Displacement of the camera/display unit can be effected through the presence of a grip to be operated by the hand of the observer. If the quite position is found relative to the member the hand of the observer can be used to execute the related treatment to the vein or artery.