RADIOGRAPHIC IMAGE DETECTION DEVICE AND METHOD FOR OPERATING THE SAME

• US 20200132864A1
• Filed: 12/26/2019
• Published: 04/30/2020
• Est. Priority Date: 06/28/2017
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: SHIMIZUKAWA, Syo, IWAKIRI, Naoto, KITANO, Kouichi
• Granted Patent: US 11,313,979 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 6/4233 using matrix detectors
• CPC Class Codes: G01N 2223/304 electric circuits, signal processing
• CPC Class Codes: G01N 23/04 and forming images of the material
• CPC Class Codes: G01T 1/17 Circuit arrangements not adapted to a particular type of detector pulse-selection circuits H03K, G01R
• CPC Class Codes: H04N 25/709 Circuitry for control of the power supply
• CPC Class Codes: H04N 25/75 Circuitry for providing, modifying or processing image signals from the pixel array
• CPC Class Codes: H04N 5/32 Transforming X-rays cameras or camera modules for generating image signals from X-rays H04N23/30; circuitry of SSIS for transforming X-rays into image signals H04N25/30

Abstract

A control unit of an electronic cassette switches the power supply state of a plurality of blocks BL which share a signal processing of a signal processing circuit between an operating state and a non-operating state. The control unit switches the block BL from the non-operating state to the operating state before a predetermined time TW necessary for stable operation of the block BL from a timing when the reading of charge starts in the block BL.

Claims

1. 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, and has a plurality of blocks which share the signal processing for each area that is formed by the pixels connected to a plurality of the adjacent signal lines; 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 from the pixel through the signal line 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 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,

the processor has a function of switching a power supply state of the block between a first state in which first power is supplied and a second state in which second power lower than the first power per unit time is supplied,

the processor switches the power supply state of the plurality of blocks during the irradiation start detection operation, and

the processor switches the block from the second state to the first state before a predetermined time necessary for stable operation of the block from a timing when the reading of charge starts in the block.

2. The radiographic image detection device according to claim 1,

wherein the signal processing circuit includes

a plurality of charge amplifiers 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 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, and

an AD converter that 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,

one of the blocks includes one multiplexer connected to the plurality of charge amplifiers and one AD converter connected to a stage behind the one multiplexer.

3. The radiographic image detection device according to claim 1,

wherein the processor periodically switches the power supply state of at least one of the plurality of blocks during the irradiation start detection operation.

4. The radiographic image detection device according to claim 3,

wherein in a case where the number of blocks whose power supply state is periodically switched is two or more, the processor shifts a switching timing of the power supply state of at least two of the two or more blocks.

5. The radiographic image detection device according to claim 4,

wherein the two or more blocks are divided into groups, and

the processor shifts the switching timing of the power supply state for each group.

6. The radiographic image detection device according to claim 5,

wherein at least one block is disposed between two blocks belonging to the same group.

7. The radiographic image detection device according to claim 6,

wherein the processor shifts the switching timing of the power supply state of all of the two or more blocks.

8. The radiographic image detection device according to claim 1,

wherein a plurality of the adjacent blocks that are in charge of the areas adjacent to each other are mounted on the same chip, and a plurality of the chips are provided.

9. The radiographic image detection device according to claim 8,

wherein the processor switches the power supply state of the block in units of the blocks that are in charge of the areas or in units of the chips.

10. The radiographic image detection device according to claim 1,

wherein the processor switches the block from the first state to the second state at a timing that does not overlap a timing when the charge is read in another block.

11. The radiographic image detection device according to claim 10,

wherein the processor switches the block from the first state to the second state at a timing before reading of the charge starts in another block.

12. The radiographic image detection device according to claim 10,

wherein the processor switches the block from the first state to the second state at a timing after reading of the charge ends in another block.

13. The radiographic image detection device according to claim 10,

wherein the processor switches the block from the first state to the second state at a timing between intermittent periods in which the charge is read in another block.

14. The radiographic image detection device according to claim 3,

wherein all of the blocks are set in the first state until the image reading operation starts after the start of the emission is detected, and

all of the blocks are set in the first state until one cycle of switching all of the plurality of blocks ends after the start of the emission is detected.

15. The radiographic image detection device according to claim 1,

wherein the signal line includes a detection channel connected to a detection pixel which is preset for irradiation start detection among the signal lines and a non-detection channel other than the detection channel,

a detection charge amplifier connected to the detection channel and a non-detection charge amplifier connected to the non-detection channel are mixed in a plurality of charge amplifiers connected to the multiplexer included in the block, and

in the irradiation start detection operation, the multiplexer sequentially selects all of the detection charge amplifiers and the non-detection charge amplifiers and outputs the analog voltage signal to the AD converter.

16. The radiographic image detection device according to claim 1,

wherein the signal line includes a detection channel connected to a detection pixel which is preset for irradiation start detection among the signal lines and a non-detection channel other than the detection channel,

a detection charge amplifier connected to the detection channel and a non-detection charge amplifier connected to the non-detection channel are mixed in a plurality of charge amplifiers connected to the multiplexer included in the block, and

in the irradiation start detection operation, the analog voltage signal from a part of the charge amplifiers including the detection charge amplifier among the plurality of charge amplifiers connected to the multiplexer is selectively output to the AD converter.

17. The radiographic image detection device according to claim 1,

wherein the processor corrects a temperature drift of the digital signal which is generated by a bias in a temperature distribution in the signal processing circuit due to the switching of the power supply state of the block.

18. The radiographic image detection device according to claim 1,

wherein the signal processing circuit includes

a plurality of charge amplifiers 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 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,

a first path through which the charge is input to the charge amplifier,

a second path through which the charge is output to the multiplexer without passing through the charge amplifier, and

a switch that selectively switches between the first path and the second path,

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 causes at least one of the plurality of charge amplifiers to be in a power saving state in which the supply power is lower than the normal power, and

the processor controls the switch to select the second path for the charge amplifier in the power saving state.

19. The radiographic image detection device according to claim 18,

wherein, in a case in which the power saving state is a power-off state in which the supply of power is stopped, the processor applies a bias voltage for stabilizing a potential of an input stage to the charge amplifier in the power-off state.

20. 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, and has a plurality of blocks which share the signal processing for each area that is formed by the pixels connected to a plurality of the adjacent signal lines, and a processor configured to control the signal processing circuit, the method comprising:

an irradiation start detection step of performing an irradiation start detection operation that reads the charge from the pixel through the signal line 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 and the image reading step, the power supply state of the block is switched between a first state in which first power is supplied and a second state in which second power lower than the first power per unit time is supplied,

in the irradiation start detection step, the power supply state of the plurality of blocks is switched, and

the block is switched from the second state to the first state before a predetermined time necessary for stable operation of the block from a timing when the reading of charge starts in the block.