| 摘要 |
<p>PURPOSE: To correct deterioration of a diagnostic image by installing a means to adjust the electric current applied to an anode so as to reduce the difference between the designated X-ray radiation dose and the applied X-ray radiation dose in a control circuit. CONSTITUTION: In a filament electric power source 40 of an X-ray tube controlling circuit C, the filament electric current of the X-ray tube A is adjusted based on the X-ray radiation dose selected by an electric current selecting means 24 and a radiation dose selecting means 26 of an input means 20 by an operator. A practical electric current detecting means generates a mA feedback signal to display the actual anode current and a comparing means, for example a mA signal adding node 42, carries out comparison of the actual electric current with the selected electric current and generates a corresponding mA error signal. A film concentration correcting means 60 increases a prescribed anode-operating electric current mA value to the necessary extent and increases or decreases the filament electric power source 40 until the selected electric current and the actual anode-operating electric current become same by the mA error signal and the deterioration of a diagnostic image can be corrected.</p> |
