Radiation image detecting device and method for detecting start of irradiation

• US 8,953,744 B2
• Filed: 01/31/2012
• Issued: 02/10/2015
• Est. Priority Date: 02/09/2011
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: Watanabe, Keita, Noma, Kentaro
• Primary Examiner(s): Ho, Allen C.
• Application Number:
  US13/362,857
• Publication Number:
  US 20120201357A1
• Time in Patent Office: 1,106 Days
• Field of Search: 378/19, 378/62, 378/91, 378/98.7, 378/98.8, 378114-116, 250/370.09
• US Class Current: 378/98.8
• CPC Class Codes: A61B 6/4233 using matrix detectors
• CPC Class Codes: H04N 23/631 Graphical user interfaces [GUI] specially adapted for controlling image capture or setting capture parameters
• CPC Class Codes: H04N 25/63 applied to dark current
• CPC Class Codes: H04N 25/70 SSIS architectures; Circuits associated therewith
• 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
• CPC Class Codes: H05G 1/64 Circuit arrangements for X-ray apparatus incorporating image intensifiers

Abstract

An FPD, being offline from an X-ray source, detects X-ray irradiation from the X-ray source to detect an X-ray image. The FPD includes pixels arranged in two dimensions, scan lines corresponding to respective rows of the pixels, signal lines corresponding to respective columns of the pixels, and switching elements provided to the respective pixels to allow performing accumulation operation or readout operation. At least one of the pixels is used as a detection pixel to detect a start of the X-ray irradiation. First and second voltage signals are obtained successively through the signal line to which the detection pixel is connected. The start of the X-ray irradiation is judged based on a difference between the first and second voltage signals.

Claims

1. A radiation image detecting device for imaging a subject irradiated with radiation from a radiation source to obtain a radiological image, the radiation image detecting device comprising:

a plurality of pixels arranged in two-dimensions along row and column directions in an imaging area, each pixel of the plurality of pixels generating signal charge corresponding to an amount of the radiation incident on the pixel, each pixel of the plurality of pixels having a switching element for controlling reading of the signal charge;

a plurality of scan lines extending in the row direction, each scan line of the plurality of scan lines being connected to gate electrodes of the respective switching elements of the corresponding pixels;

a plurality of signal lines extending in the column direction, each signal line of the plurality of signal lines being connected to the corresponding pixels through the switching elements;

a drive section for turning off the switching element of the pixel to allow performing accumulation operation and for turning on the switching element of the pixel to allow performing readout operation, the signal charge generated in the pixels being accumulated in the accumulation operation, the signal charge accumulated being read out through the signal line connected to the pixel in the readout operation; and

a controller using at least one of the plurality of pixels as a detection pixel for judging start of irradiation with the radiation, the controller successively obtaining two output values, being first and second signal values, from the signal line connected to the detection pixel, the controller judging whether the irradiation with the radiation is started based on a difference between the first and second signal values, the controller controlling the drive section based on the judgment.

2. The radiation image detecting device according to claim 1, wherein the controller obtains a first difference between the first and second signal values, and judges that the irradiation is started when the first difference is greater than or equal to a first threshold value.

3. The radiation image detecting device according to claim 2, wherein the controller carries out the steps of:

starting the accumulation operation through the drive section when the first difference reaches greater than or equal to a second threshold value during irradiation detecting operation;

continuing the accumulation operation for a predetermined time to obtain the radiological image when it is judged, after a start of the accumulation operation, that the irradiation is started; and

aborting the accumulation operation and resuming the irradiation detecting operation when the controller judges that the irradiation is not started.

4. The radiation image detecting device according to claim 3, further including a correction section for correcting a pixel value of the pixels of a row in which the detection pixel is located.

5. The radiation image detecting device according to claim 2, wherein the controller carries out the step of starting the accumulation operation through the drive section to obtain the radiological image when the controller judges that the irradiation is started during the irradiation detecting operation.

6. The radiation image detecting device according to claim 1, wherein the first signal value is obtained when the switching element of the detection pixel is in an ON state, and the second signal value is obtained when the switching element of the detection pixel is in an OFF state.

7. The radiation image detecting device according to claim 1, wherein the first and second signal values are obtained when the switching element is in an ON state.

8. The radiation image detecting device according to claim 1, wherein the controller using two or more of the plurality of pixels as detection pixels.

9. The radiation image detecting device according to claim 1, wherein the detection pixel is located close to a center of the imaging area.

10. The radiation image detecting device according to claim 1, wherein the signal line is connected to an integrating amplifier for converting the signal charge into a voltage signal.

11. A method for detecting start of irradiation with radiation from a radiation source to a radiation image detecting device, the radiation image detecting device having a plurality of pixels arranged in two dimensions and a plurality of switching elements used for accumulation and readout of signal charge in the respective pixels, the method comprising using one or more processors to perform the steps of:

using at least one of the plurality of pixels as a detection pixel;

successively obtaining output values, being a first and second signal values, of a signal line connected to the detection pixel;

judging whether the irradiation with the radiation is started based on a difference between the first and second signal values; and

controlling accumulation operation of each of the pixels in accordance with a result of the judgment.

12. The method according to claim 11, wherein judging whether the irradiation with the radiation is started when the difference between the first and second signal values is greater than or equal to a first threshold value.

13. The method according to claim 12, wherein successively obtaining output values comprises obtaining the first signal value when the switching element is in an ON state, and the second signal value when the switching element is in an OFF state.

14. The method according to claim 12, wherein successively obtaining output values comprises obtaining the first and second signal values when the switching element is in an ON state.

15. The method according to claim 12, further including the steps of:

starting the accumulation operation through a drive section when the difference is greater than or equal to a second threshold value during irradiation detecting operation;

continuing the accumulation operation for a predetermined time to obtain the radiological image when it is judged, after a start of the accumulation operation, that the irradiation is started; and

aborting the accumulation operation and resuming the irradiation detecting operation when it is judged that the irradiation is not started.

16. The method according to claim 12, further including the step of starting the accumulation operation through a drive section to obtain the radiological image when it is judged that the irradiation is started during the irradiation detecting operation.