X-ray CT apparatus and X-ray detector with variable layer

Patent metadata

Field	Value
Publication number	US-10197511-B2
Application number	US-201514831086-A
Country	US
Kind code	B2
Filing date	Aug 20, 2015
Priority date	Aug 20, 2014
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

An X-ray computer tomography (CT) apparatus according to an embodiment includes an X-ray source, an X-ray detector, and generating circuitry. The X-ray source radiates X-rays. The X-ray detector includes a scintillator including a first region close to the X-ray source and a second region distant from the X-ray source, an optical sensor that detects scintillator light obtained by converting the X-rays radiated from the X-ray source with the scintillator, and a variable layer that is provided in the scintillator and switchable between a first state in which the variable layer transmits the scintillator light between the first region and the second region and a second state in which the variable layer does not transmit the scintillator light between the first region and the second region. The generating circuitry generates a CT image based on a signal output from the X-ray detector.

First claim

What is claimed is:

1. An X-ray computer tomography (CT) apparatus, comprising:
an X-ray source configured to radiate X-rays;
an X-ray detector including a scintillator including a first region close to the X-ray source and a second region distant from the X-ray source, at least one optical sensor configured to detect scintillator light obtained by converting the X-rays radiated from the X-ray source with the scintillator, and a variable layer that is provided in the scintillator and switchable between a first state in which the variable layer transmits the scintillator light between the first region and the second region and a second state in which the variable layer does not transmit the scintillator light between the first region and the second region;
switching control circuitry configured to switch the variable layer between the first state and the second state during application of the X-rays; and
generating circuitry configured to generate a CT image based on a signal output from the X-ray detector.

2. The X-ray CT apparatus according to claim 1 , wherein the at least one optical sensor includes two optical sensors, disposed at opposite ends of the scintillator in an X-ray incident direction.

3. The X-ray CT apparatus according to claim 1 , wherein the at least one optical sensor includes one optical sensor disposed at one end of the scintillator in an X-ray incident direction.

4. The X-ray CT apparatus according to claim 1 , wherein the switching control circuitry is further configured to switch the variable layer to the second state when a set value that is set as an imaging condition is equal to or higher than a predetermined threshold.

5. The X-ray CT apparatus according to claim 1 , wherein the switching control circuitry is further configured to switch the variable layer to the second state when an intensity of a signal detected by the X-ray detector is equal to or higher than a predetermined threshold.

6. The X-ray CT apparatus according to claim 1 , wherein the switching control circuitry is further configured to switch the variable layer to the second state when an upper limit of an energy band of emitted X-rays determined based on an imaging condition is equal to or higher than a predetermined threshold.

7. The X-ray CT apparatus according to claim 1 , wherein the switching control circuitry is further configured to switch the variable layer to the second state when a number of counts of signals having an energy band equal to or higher than a predetermined energy value among signals detected by the X-ray detector is equal to or higher than a predetermined threshold.

8. The X-ray CT apparatus according to claim 1 , further comprising an additional variable layer, which is disposed in at least one of the first region and the second region in the scintillator.

9. The X-ray CT apparatus according to claim 8 , wherein the switching control circuitry is further configured to control switching of each of the variable layers between the first state and the second state, in accordance with an intensity of a signal detected by the X-ray detector.

10. The X-ray CT apparatus according to claim 9 , wherein, when the intensity of the signal detected by the X-ray detector exceeds any of a plurality of thresholds set for the intensity of the signal, the switching control circuitry refers to association information that associates the thresholds with the respective variable layers, specifies a specific variable layer, of the variable layers, associated with a threshold of a highest value among the thresholds that the intensity of the signal exceeds, and switches the specified variable layer to the second state.

11. The X-ray CT apparatus according to claim 8 , wherein the switching control circuitry is further configured to refer to, when a set value that is set as an imaging condition exceeds any of a plurality of thresholds that are set for the imaging condition, association information that associates the thresholds with the respective variable layers, specify a specific variable layer, of the variable layers, associated with a threshold of a highest value among the thresholds that the set value exceeds, and switch the specified variable layer to the second state.

12. The X-ray CT apparatus according to claim 8 , wherein the switching control circuitry is further configured to classify intensities of the incident X-rays based on a scanogram, specify a specific variable layer, of the variable layers, with reference to association information that associates the classified intensities of the incident X-rays with the respective variable layers, and switch the specified variable layer to the second state.

13. The X-ray CT apparatus according to claim 8 , wherein the switching control circuitry is further configured to refer to, when an upper limit of an energy band of emitted X-rays determined based on an imaging condition exceeds any of a plurality of thresholds that are set for the upper limit, association information that associates the thresholds with the respective variable layers, specify a specific variable layer, of the variable layers, associated with a threshold of a highest value among the thresholds that the upper limit exceeds, and switch the specified variable layer to the second state.

14. The X-ray CT apparatus according to claim 8 , wherein the switching control circuitry is further configured to refer to, when a number of counts of signals having an energy band equal to or higher than a predetermined energy value among signals detected by the X-ray detector exceeds any of a plurality of thresholds that are set for the number of counts of signals, association information that associates the thresholds with the respective variable layers, specify a variable layer, of the variable layers, associated with a threshold of a highest value among the thresholds that the number of counts of signals exceeds, and switch the specified variable layer to the second state.

15. The X-ray CT apparatus according to claim 8 , further comprising receiving circuitry configured to receive setting of an energy band of X-rays to be collected,
wherein the switching control circuitry is further configured to control switching of each of the variable layers between the first state and the second state, in accordance with the energy band, the setting of which has been received by the receiving circuitry.

16. The X-ray CT apparatus according to claim 15 , wherein the switching control circuitry controls switching of each of the variable layers in each detection element between the first state and the second state, to enable detection of incident X-rays of energy bands that are different between detection elements that are adjacent in a predetermined direction.

17. The X-ray CT apparatus according to claim 1 , wherein the at least one optical sensor includes two optical sensors disposed at opposite ends of the scintillator, and the generating circuitry generates the CT image based on at least one of signals that are output from the two optical sensors.

18. The X-ray CT apparatus according to claim 1 , wherein a plurality of detection elements, each of which includes the scintillator, the optical sensor, and the variable layer, are arranged in a two-dimensional manner on a surface.

19. An X-ray computer tomography (CT) apparatus comprising:
an X-ray source configured to radiate X-rays;
an X-ray detector including a scintillator including a first region close to the X-ray source and a second region distant from the X-ray source, an optical sensor configured to detec

Assignees

• Toshiba Medical Sys Corp

Inventors

• Kato Tooru
• Nakai Hiroaki
• Hayashi Mikihito

Classifications

• G01T1/2985

  In depth localisation, e.g. using positron emitters; Tomographic imaging (longitudinal and transverse section imaging; apparatus for radiation diagnosis sequentially in different planes, steroscopic radiation diagnosis); (using external radiation sources A61B6/02) · CPC title

• G01N23/046 Primary

  using tomography, e.g. computed tomography [CT] · CPC title

• G01N2223/505

  scintillation · CPC title

• G01T1/17

  Circuit arrangements not adapted to a particular type of detector {(pulse-selection circuits H03K, G01R)} · CPC title

• G01T1/2002

  Optical details, e.g. reflecting or diffusing layers · CPC title