Radiation imaging apparatus, radiation imaging system, and radiation imaging method

A radiation imaging apparatus that obtains a radiation image by an energy subtraction method of obtaining a new image by processing a plurality of images obtained by capturing an object a plurality of times while changing energy of radiation to irradiate the object, the apparatus comprising:

• a pixel array comprising a plurality of pixels;
• each of the plurality of pixels comprising a conversion element configured to convert radiation into an electrical signal and a reset portion configured to reset the conversion element, wherein
• each of the plurality of pixels is configured to perform an operation of outputting a first signal corresponding to an electrical signal generated by the conversion element in a first period, and an operation of outputting a second signal corresponding to an electrical signal generated by the conversion element in the first period and a second period different from the first period,
• each of the first signal and the second signal is generated without destructing an electrical signal generated in the conversion element,
• radiation having first energy is emitted in the first period, and radiation having second energy different from the first energy is emitted in the second period, and
• in each of the plurality of pixels, the first period starts after the conversion element is reset, the conversion element is not reset during a period that includes the first period and the second period, and the conversion element is reset after the second period.

A radiation imaging apparatus that obtains a radiation image by an energy subtraction method of obtaining a new image by processing a plurality of images obtained by capturing an object a plurality of times while changing energy of radiation to irradiate the object, the apparatus comprising:

• a pixel array comprising a plurality of pixels;
• each of the plurality of pixels comprises a conversion element configured to convert radiation into an electrical signal and having a charge accumulation portion configured to accumulate charges generated in accordance with the radiation, a charge-voltage convertor configured to convert the charges into a voltage, and a transistor having a first main electrode connected to the charge-voltage convertor, wherein
• each of the plurality of pixels is configured to perform an operation of outputting a first signal corresponding to an electrical signal generated by the conversion element in a first period, and an operation of outputting a second signal corresponding to an electrical signal generated by the conversion element in the first period and a second period different from the first period,
• radiation having first energy is emitted in the first period, and radiation having second energy different from the first energy is emitted in the second period, and
• in each of the plurality of pixels, a voltage applied to a control electrode of the transistor does not change during a period that includes the first period and the second period.

A radiation imaging method of obtaining a radiation image using a radiation imaging apparatus in an energy subtraction method of obtaining a new image by processing a plurality of images obtained by capturing an object a plurality of times while changing energy of radiation to irradiate the object,

• the radiation imaging apparatus including a pixel array that includes a plurality of pixels, and each of the plurality of pixels including a conversion element configured to convert radiation into an electrical signal and having a charge accumulation portion configured to accumulate charges generated in accordance with the radiation, a charge-voltage convertor configured to convert the charges into a voltage, and a reset portion configured to reset the charge-voltage convertor,
• the method comprising:
• causing each of the plurality of pixels to perform an operation of outputting a first signal corresponding to an electrical signal generated by the conversion element in a first period, and an operation of outputting a second signal corresponding to an electrical signal generated by the conversion element in the first period and a second period different from the first period, and
• obtaining a radiation image based on a signal corresponding to the first signal and a signal corresponding to the second signal,
• each of the first signal and the second signal is generated without destructing charges accumulated in the charge accumulation portion, wherein
• radiation having first energy is emitted in the first period, and radiation having second energy different from the first energy is emitted in the second period, and
• in the causing and the obtaining, in each of the plurality of pixels, the first period starts after the charge-voltage convertor is reset, the charge-voltage convertor is not reset during a period that includes the first period and the second period, and the charge-voltage convertor is reset after the second period.