US 2005/0031079 A1Published application

Radiographic apparatus and radiation detection signal processing method

OwnerShoichi Okamura, Keiichi Fujii +6inventors

InventorsShoichi Okamura, Keiichi Fujii, Susumu Adachi, Shinya Hirasawa, Toshinori Yoshimuta, Koichi Tanabe, Shigeya Asai, Akihiro Nishimura

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Abstract

A radiographic apparatus removes lag-behind parts from radiation detection signals taken from an FPD as X rays are emitted from an X-ray tube, on an assumption that the lag-behind part included in each X-ray detection signal is due to an impulse response formed of a plurality of exponential functions with different attenuation time constants. The lag-behind parts are removed by using impulse responses of the FPD corresponding, for example, to an X-ray dose used in a fluoroscopic image pickup and an X-ray dose used in a radiographic image pickup. X-ray images are created from corrected radiation detection signals with the lag-behind parts removed therefrom.

Claims19

Dependent claims

A radiographic apparatus having radiation emitting means for emitting radiation toward an object under examination, radiation detecting means for detecting radiation transmitted through the object under examination, and signal sampling means for taking radiation detection signals from the radiation detecting means at predetermined sampling time intervals, for obtaining radiographic images based on the radiation detection signals outputted from the radiation detecting means at the predetermined sampling time intervals as radiation is emitted to the object under examination, said apparatus comprising:

time lag removing means for removing lag-behind parts from the radiation detection signals by a recursive computation, on an assumption that a lag-behind part included in each of said radiation detection signals taken at the predetermined sampling time intervals is due to an impulse response formed of a plurality of exponential functions with different attenuation time constants;
wherein said time lag removing means is arranged to determine said impulse response based on a dose of radiation, and obtain a corrected radiation detection signal by removing the lag-behind part based on said impulse response corresponding to said dose.

A radiation detection signal processing method for taking, at predetermined sampling time intervals, radiation detection signals generated by irradiating an object under examination, and performing a signal processing to obtain radiographic images based on the radiation detection signals outputted at the predetermined sampling time intervals, said method comprising the steps of:

removing lag-behind parts from the radiation detection signals by a recursive computation, on an assumption that a lag-behind part included in each of said radiation detection signals taken at the predetermined sampling time intervals is due to an impulse response formed of a plurality of exponential functions with different attenuation time constants;
determining said impulse response based on a dose of radiation;
and
obtaining a corrected radiation detection signal by removing the lag-behind part based on said impulse response corresponding to said dose.

1 more element

Dependencies are inferred from the claim text.