Bi-focal collimator

A collimator suitable for use in the creation of more than one miniaturized image of a radioactive concentration simultaneously by a radiation receiving and imaging device, said collimator having at least two adjacent collimating sections separated by areas substantially opaque to radiation from the radioactive object, each such collimating section being a grid-like arrangement of wall portions, adapted to absorb substantially all radiation from the radioactive object which impinges thereon, extending between the top surface and the bottom surface of the collimator defining a plurality of holes therebetween of substantially any desired cross-sectional shape. The wall portions and associated holes of each collimating section are so disposed relative to each other that radiation from the radioactive object passing through the holes from the bottom to the top of the collimator will converge upon a point on a line passing through the center of the top surface of the collimating section located at an acute angle to a line normal to the center of the top surface of that collimating section. Two limitations must be adhered to. First, care must be taken in selecting the angle at which each collimating section converges to avoid interference between or among the image creating radiation rays emerging from the various collimating sections, and second each collimating section must contain sufficient wall portions to provide adequate selection of image creating radiation from the continuum of radiation radiated by the object and impinging upon the bottom surface of each section to allow the creation of a useable image