Tomographic scanner

摘要

A CT scanner includes a stationary gantry (10) defining an examination region (12) and a rotating gantry (16) which rotates about the examination region. At least two x-ray tubes (18a, 18b), each capable of producing a beam of radiation directed through the examination region, are mounted to the rotating gantry. The x-ray tubes are switchably connected to an electrical power supply (24). X-rays are detected by an arc of x-ray detectors (14) which generate signals indicative of the radiation received. These signals are processed by a reconstruction processor (32) into an image representation. A thermal calculator (60) estimates when an anode in one of the x-ray tubes (18) reaches a selected temperature. The thermal calculator (60) controls a switch (28) which is electrically connected between the x-ray tubes and the power supply. The switch selectively switches power from the power supply alternately to the x-ray tubes. Each time the thermal calculator estimates that the anode of one of the x-ray tubes has reached selected temperature, that tube is switched off and the other tube is switched on. <IMAGE>