[Radiation to the orbits during computer tomography with the emi scanner ct 1010 (author's transl)]

Radiation dose to the lens during examinations with the EMI scanner CT 1010 depends on the region examined, on the angle of swing, duration of scan and the plane of the examination. In the most common position (horizontal, 180 degrees and 60 seconds) lens dose during examination of the orbit is about 900 mR., and for examination of the skull about 300 mR. Longer durations of scan and greater swings may increase the dose to the lens to 9 R. Even in the most unfavourable cases, the dose to the lens is less than would be obtained from skull tomography and skull angiography in two planes. Nevertheless, axial computer tomography used under certain conditions, and particularly when repeated, will have to be considered as a possible cause of damage to the lens.