Tokyo Shibaura Denki Kabushiki Kaisha

Senzo Fujii

Michitaka Honda

Ichiro Ogura

Kenichi Komatsu

Motomu Suzuki

An X-ray diagnostic apparatus comprising an X-ray source for irradiating X rays to a patient, an image intensifier tube for converting an X-ray image, formed by transmitting X rays through the patient to an optical image, a television camera for receiving the optical image from the image intensifier tube through a diaphragm to output the video signal. In this pick-up apparatus, the X-ray source pre-irradiates one time a small dose of X-rays before main irradiation and there are provided a detector for detecting the maximum value of the video signal produced from the camera at the time of pre-irradiation, and an arithmetic operation circuit for calculating a diaphragm value from the maximum value detected and from pick-up conditions except a diaphragm value at the time of main irradiation of X rays in such a way that the maximum value of the video signal from the camera at the time of main irradiation becomes equal to the maximum permissible value of the camera.

X-ray diagnostic apparatus comprising X-ray intensity and diaphragm

A diagnostic X-ray apparatus emitting pulsed X-ray radiation includes a processor for performing digital X-ray subtraction of a previous mask image from current images. The apparatus includes circuitry for digitization of the video signals from an image intensifier-TV chain, digital subtraction to obtain digital difference signals, and subsequent reconversion of the resultant digital difference video signals to analog signals. Pulsed X-ray exposures are performed during the blanking periods of the TV camera following which the television fields immediately following the pulsed X-ray exposure are scanned and read out, and are supplied to the processor for performing the digital X-ray subtraction.

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Nishinasuno, Japan

Senzo Fujii