Radiation image detecting device and radiation imaging system

• US 9,629,601 B2
• Filed: 10/17/2014
• Issued: 04/25/2017
• Est. Priority Date: 04/20/2012
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: Tajima, Takashi, Kuwabara, Takeshi, Kitagawa, Yusuke
• Primary Examiner(s): THOMAS, COURTNEY D
• Application Number:
  US14/516,625
• Publication Number:
  US 20150036802A1
• Time in Patent Office: 921 Days
• Field of Search: 378 62, 378 95- 98, 378145-155
• CPC Class Codes: A61B 6/4208 characterised by using a particular type of detector
• CPC Class Codes: A61B 6/4233 using matrix detectors
• CPC Class Codes: A61B 6/4283 characterised by a detector unit being housed in a cassette
• CPC Class Codes: A61B 6/4291 the detector being combined with a grid or grating
• CPC Class Codes: A61B 6/542 involving control of exposure
• CPC Class Codes: G01T 1/08 Photographic dosimeters photometry G01J1/52

Abstract

In a detection panel, plural pixels which receive X-ray and accumulate electric charge and plural measuring pixels which detect X-ray dose are provided on an imaging surface. The plural measuring pixels are arranged periodically with an interval. In a position facing to the imaging surface, there is a grid where X-ray absorbing sections and X-ray transmitting sections are arranged in a periodic alternating manner in a first direction. Since the arrangement period of the measuring pixels in the first direction is different from a fluctuation period of grid detection signals obtained when the grid is photographed by the detection panel, output values of the plurality of measuring pixels disperse and a fluctuation range of average values is suppressed.

Claims

1. A radiation image detecting device being able to perform photography with using an anti-scatter grid where radiation absorbing sections which absorb radiation and radiation transmitting sections which transmit radiation are arranged in a periodic alternating manner in a first direction, said radiation image detecting device comprising:

a detection panel having an imaging surface where plural pixels for receiving radiation from a radiation source are provided, a radiation image of an object being detected by said pixels receiving radiation which penetrated an object; and

a plurality of dose measuring sensors provided to perform exposure control of said radiation image, being arranged in said imaging surface in said first direction periodically with keeping a space, and detecting radiation dose which penetrated said object to output a signal depending on said dose,

wherein said plural dose measuring sensors are arranged so that an arrangement period of said plural dose measuring sensors in said first direction in said imaging surface differs from a fluctuation period of a grid detection signal representing an image of said anti-scatter grid which is obtained when radiation is irradiated equally to said imaging surface and said anti-scatter grid is photographed by said detection panel, an output value of said grid detection signal fluctuating periodically by reflecting an arrangement state in said first direction of said radiation absorbing section and said radiation transmitting section.

2. The radiation image detecting device according to claim 1,

wherein said arrangement period of said dose measuring sensors is not an integral multiple of said fluctuation period of said grid detection signal.

3. The radiation image detecting device according to claim 1,

wherein said arrangement period of said dose measuring sensors and said fluctuation period of said grid detection signal are relatively prime.

4. The radiation image detecting device according to claim 1,

wherein said arrangement period of said dose measuring sensors is different from said fluctuation period of said grid detection signal also in a second direction which is perpendicular to said first direction.

5. The radiation image detecting device according to claim 4,

wherein said arrangement period of said dose measuring sensors in said first direction and said arrangement period of said dose measuring sensors in said second direction are the same.

6. The radiation image detecting device according to claim 1,

wherein the minimum size of said single dose measuring sensor is the same as a size of said pixel in said imaging surface.

7. The radiation image detecting device according to claim 1,

wherein a pixel pitch of said pixels is larger than half of a grid pitch which is the width of one set of said radiation absorbing section and said radiation transmitting section in said anti-scatter grid.

8. The radiation image detecting device according to claim 1,

wherein said dose measuring sensors are measuring pixels using a part of said pixels.

9. The radiation image detecting device according to claim 4,

wherein said dose measuring sensors are measuring pixels using a part of said pixels, and

wherein said plural measuring pixels are arranged in a line direction corresponding to said first direction and a column direction corresponding to said second direction with an interval corresponding to at least one line or one column in the each direction, and said arrangement period in said first direction is an interval length in said line direction, and said arrangement period in said second direction is an interval length in said column direction.

10. The radiation image detecting device according to claim 8,

wherein said single dose measuring sensor is a measuring pixel group consisting of a plurality of adjacent said measuring pixels.

11. The radiation image detecting device according to claim 10,

wherein said arrangement period is an arrangement period of a plurality of said plural measuring pixel groups which are arranged periodically with an interval.

12. The radiation image detecting device according to claim 1,

wherein said dose measuring sensor outputs a signal corresponding to a dose per unit time, and

wherein said radiation image detecting device further comprises an automatic exposure controller which multiplies output values from said dose measuring sensors, compares said multiplied integrated value with a predetermined emission stop threshold value, and stops irradiation of radiation from said radiation source when said integrated value reaches said emission stop threshold value.

13. The radiation image detecting device according to claim 12,

wherein said automatic exposure controller calculates the average value of output values from said plural dose measuring sensors, and multiplies said calculated average values to obtain said integrated value.

14. The radiation image detecting device according to claim 1,

wherein said anti-scatter grid is detachably attached to said radiation image detecting device.

15. A radiation imaging system being able to perform photography with using an anti-scatter grid where radiation absorbing sections which absorb radiation and radiation transmitting sections which transmit radiation are arranged in a periodic alternating manner in a first direction, said radiation imaging system comprising:

a radiation generator including a radiation source for irradiating radiation; and

a radiation image detecting device for detecting a radiation image,

said radiation image detecting device including;

a detection panel having an imaging surface where plural pixels for receiving radiation from a radiation source are provided, a radiation image of an object being detected by said pixels receiving radiation which penetrated an object; and

a plurality of dose measuring sensors provided to perform exposure control of said radiation image, being arranged in said imaging surface in said first direction periodically with keeping a space, and detecting radiation dose which penetrated said object to output a signal depending on said dose,

wherein said plural dose measuring sensors are arranged so that an arrangement period of said plural dose measuring sensors in said first direction in said imaging surface differs from a fluctuation period of a grid detection signal representing an image of said anti-scatter grid which is obtained when radiation is irradiated equally to said imaging surface and said anti-scatter grid is photographed by said detection panel, an output value of said grid detection signal fluctuating periodically by reflecting an arrangement state in said first direction of said radiation absorbing section and said radiation transmitting section.