Radiographic image detection device and method for operating the same
AssigneeFUJIFILM Corporation
InventorsNaoto Iwakiri, Kouichi Kitano, Syo Shimizukawa
Life of this patent
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Abstract
In an AED operation of detecting irradiation start of X-rays, a control unit of an electronic cassette selectively outputs the analog voltage signal from a part of the charge amplifiers including a detection CA connected to the detection channel of a detection pixel for irradiation start detection among the plurality of CAs connected to the MUX, to the ADC, causes the ADC to perform only the AD conversion process for the analog voltage signal selectively output from the multiplexer, and reduces the number of pulses NPU_A per unit time in a clock signal defining an operation timing of the ADC compared to that in the image reading operation.
Claims20
A radiographic image detection device comprising:
- a sensor panel in which pixels that are sensitive to radiation which has been emitted from a radiation generation apparatus and transmitted through a subject and accumulate charge are two-dimensionally arranged and a plurality of signal lines for reading the charge are arranged;
- a signal processing circuit that reads an analog voltage signal corresponding to the charge from the pixel through the signal line to perform signal processing;
- a plurality of charge amplifiers that are included in the signal processing circuit and each of which is provided for each signal line, is connected to one end of the signal line, and converts the charge from the pixel into the analog voltage signal;
- a multiplexer that is included in the signal processing circuit, has a plurality of input terminals to which the plurality of charge amplifiers are respectively connected, sequentially selects the analog voltage signals from the plurality of charge amplifiers, and outputs the selected analog voltage signal;
- an AD converter that is included in the signal processing circuit, is connected to a stage behind the multiplexer, and performs an AD conversion process of converting the analog voltage signal output from the multiplexer into a digital signal corresponding to a voltage value;
- and
- a processor configured to control the signal processing circuit such that an irradiation start detection operation and an image reading operation are performed,
- wherein the irradiation start detection operation reads the charge through a detection channel which is the signal line connected to a preset detection pixel among the pixels from before start of the emission of the radiation and detects the start of the emission of the radiation on the basis of the digital signal corresponding to the read charge,
- the image reading operation reads the charge from the pixel through the signal line after a pixel charge accumulation period for which the charge is accumulated in the pixel elapses after the start of the emission of the radiation and outputs a radiographic image which is indicated by the digital signal corresponding to the read charge and is provided for diagnosis, and
- in the irradiation start detection operation, the processor selectively outputs the analog voltage signal from a part of the charge amplifiers including a detection charge amplifier that is the charge amplifier connected to the detection channel among the plurality of charge amplifiers connected to the multiplexer, to the AD converter,
- the processor causes the AD converter to perform only the AD conversion process for the analog voltage signal selectively output from the multiplexer,
- the processor further reduces the number of pulses per unit time in a clock signal defining an operation timing of the AD converter compared to that in the image reading operation, and
- in the irradiation start detection operation, in a case where power supplied to the charge amplifier during the image reading operation is normal power, the processor further drives at least one of the part of charge amplifiers in a low power state in which power lower than the normal power and greater than 0 is supplied.
A method for operating a radiographic image detection device comprising a sensor panel in which pixels that are sensitive to radiation which has been emitted from a radiation generation apparatus and transmitted through a subject and accumulate charge are two-dimensionally arranged and a plurality of signal lines for reading the charge are arranged, a signal processing circuit that reads an analog voltage signal corresponding to the charge from the pixel through the signal line to perform signal processing, a plurality of charge amplifiers that are included in the signal processing circuit and each of which is provided for each signal line, is connected to one end of the signal line, and converts the charge from the pixel into the analog voltage signal, a multiplexer that is included in the signal processing circuit, has a plurality of input terminals to which the plurality of charge amplifiers are respectively connected, sequentially selects the analog voltage signals from the plurality of charge amplifiers, and outputs the selected analog voltage signal, an AD converter that is included in the signal processing circuit, is connected to a stage behind the multiplexer, and performs an AD conversion process of converting the analog voltage signal output from the multiplexer into a digital signal corresponding to a voltage value, and a processor configured to control the signal processing circuit such that an irradiation start detection operation and an image reading operation are performed, the method comprising:
- an irradiation start detection step of performing an irradiation start detection operation that reads the charge through a detection channel which is the signal line connected to a preset detection pixel among the pixels from before start of the emission of the radiation and detects the start of the emission of the radiation on the basis of the digital signal corresponding to the read charge;
- and
- an image reading step of performing an image reading operation that reads the charge from the pixel through the signal line after a pixel charge accumulation period for which the charge is accumulated in the pixel elapses from the start of the emission of the radiation and outputs a radiographic image which is indicated by the digital signal corresponding to the read charge and is provided for diagnosis,
- wherein in the irradiation start detection step, the analog voltage signal from a part of the charge amplifiers including a detection charge amplifier that is the charge amplifier connected to the detection channel among the plurality of charge amplifiers connected to the multiplexer is selectively output to the AD converter,
- the AD converter is caused to perform only the AD conversion process for the analog voltage signal output from the multiplexer,
- the number of pulses per unit time in a clock signal defining an operation timing of the AD converter is further reduced compared to that in the image reading operation, and
- in the irradiation start detection operation, in a case where power supplied to the charge amplifier during the image reading operation is normal power, at least one of the part of charge amplifiers is further driven in a low power state in which power lower than the normal power and greater than 0 is supplied.
Dependencies are inferred from the claim text.