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JP-7856526-B2 - Computed tomography scanner

JP7856526B2JP 7856526 B2JP7856526 B2JP 7856526B2JP-7856526-B2

Inventors

  • 清水川 将
  • 田島 崇史
  • 種市 達哉
  • 西納 直行
  • 堀内 久嗣

Assignees

  • 富士フイルム株式会社

Dates

Publication Date
20260511
Application Date
20220823

Claims (11)

  1. Multiple imaging units, each comprising a radiation source that emits cone-shaped radiation toward a subject, and a radiation detector having multiple pixels arranged in a two-dimensional manner to detect the radiation that has passed through the subject, A rotation mechanism that rotates multiple of the aforementioned shooting units around the body axis of the subject while maintaining their spacing, A processor that controls the operation of multiple imaging units and the rotation mechanism, Equipped with, The angular interval is determined by the frame rate of the radiation detector and the rotation speed of the imaging unit, and the angular interval defining the timing for acquiring the projection image based on the radiation is the same for multiple imaging units. Multiple of the aforementioned imaging units have different phases in the direction of rotation. The positions at which the projection images are acquired by the multiple imaging units differ by a set angle less than the angular interval. Computed tomography scanner.
  2. The computed tomography apparatus according to claim 1, wherein the setting angle is an angle obtained by dividing the angle interval into equal parts.
  3. The aforementioned processor, The computed tomography apparatus according to claim 1, wherein deviations in the set angle, including manufacturing errors, are corrected by varying the irradiation timing of the radiation from the radiation source.
  4. The aforementioned processor, During a predetermined first period, the radiation is irradiated from all of the multiple imaging units. The computed tomography apparatus according to claim 1, wherein the projection image is output from all of the plurality of imaging units during a predetermined second period following the first period.
  5. The aforementioned processor, During the first period, the radiation is irradiated from multiple imaging units at the same time. The computed tomography apparatus according to claim 4, wherein, during the second period, the projection images are output from a plurality of imaging units at the same time.
  6. The computed tomography apparatus according to claim 4, wherein the first period is longer than the irradiation time from the start to the end of radiation irradiation.
  7. The aforementioned processor, The computed tomography apparatus according to claim 4, wherein radiation is irradiated from multiple imaging units at different timings within the first period without overlap.
  8. The computed tomography apparatus according to claim 1, wherein the plurality of imaging units are arranged at positions that are more than 90° apart when viewed from the axis of rotation of the plurality of imaging units.
  9. The computed tomography apparatus according to claim 1, wherein, when viewed from the rotation axis direction of the multiple imaging units, the radiation detector is positioned at an offset position that differs by a predetermined angle from a reference position directly facing the radiation source.
  10. Multiple of the aforementioned shooting units are held in a frame, and the subject is positioned within the frame. The computed tomography apparatus according to claim 1, wherein, when viewed from the axis of rotation of the multiple imaging units, the radiation source is located outside the frame and the radiation detector is located inside the frame.
  11. The computed tomography apparatus according to claim 1, wherein the subject is positioned in either a standing or sitting position.

Description

The technology disclosed herein relates to computed tomography (CT) imaging equipment. Patent Document 1 describes a computed tomography (CT) scanner for imaging subjects in a supine position. To improve the efficiency of acquiring projection images, which form the basis of tomographic images, the CT scanner includes multiple imaging units, each comprising a radiation source that emits radiation toward the subject and a radiation detector that detects radiation transmitted through the subject. The multiple imaging units are arranged at equal intervals on a gantry that rotates around the subject's body axis, for example, three units at 120° intervals. The radiation source emits a cone beam, and the radiation detector has a configuration in which multiple pixels are arranged in a two-dimensional matrix. Japanese Patent Publication No. 2006-187453 This is a front view of a CT scanner.This is a side view of a CT scanner.This diagram shows the configuration of the first and second imaging units.This is a front view of a CT scanner showing a subject in a seated position in a wheelchair, positioned accordingly.This is a diagram showing a lifting mechanism.This is a diagram showing a rotating mechanism.This is a perspective view showing the radiation source, radiation detector, and radiation.This diagram shows the positions of the first and second imaging units.This diagram shows the reference position and offset position of the radiation detector.This is a block diagram showing the processing unit of the CPU of the control device.This diagram shows the acquisition positions of the projected images from the first and second imaging units.This diagram shows the acquisition positions of the projected images from the first imaging unit, the second imaging unit, and all imaging units combined.This is a timing chart showing the timing of radiation irradiation from the radiation source and the timing of reading the projected image from the radiation detector.This is a timing chart showing the details of the readout operation of the projection image from the radiation detector.This is a flowchart showing the procedure for imaging using a CT scanner.This figure shows the position of the projected image acquired by the shooting unit when the acquisition positions of the projected images from the first shooting unit and the second shooting unit are not differed by a set angle.This diagram illustrates the effect of positioning the second imaging unit at an angle greater than 90° from the first imaging unit.This diagram shows the case where the second imaging unit is positioned 125° away from the first imaging unit.This diagram shows the effective field of view when the radiation detector is in the reference position.This diagram shows the effective field of view when the radiation detector is in an offset position.This figure shows another example of the acquisition position of the projected images from the first and second imaging units.This figure shows another example of the acquisition positions for the projected images of the first imaging unit, the second imaging unit, and all imaging units.This figure shows the case where the set angle is off due to manufacturing tolerances.This figure shows a method of correcting deviations in the set angle, including manufacturing errors, by varying the timing of radiation irradiation from the radiation source.This figure shows the case where the timing of radiation exposure from the second radiation source is accelerated.This diagram illustrates the effect of making the first period longer than the total irradiation time from the start to the end of radiation exposure.This figure shows a configuration in which radiation is irradiated from multiple imaging units at different times within the first period without overlap.This diagram shows an example with three shooting units.This diagram shows the configuration of the first imaging unit, the second imaging unit, and the third imaging unit.This diagram shows the acquisition positions of the projected images from the first, second, and third imaging units.This graph shows the time-dependent change in the frame's rotation speed. As an example, as shown in Figure 1, the CT scanner 10 is a device for obtaining tomographic images of a subject S, and consists of a main unit 11 and a control device 12. The main unit 11 is installed, for example, in the imaging room of a medical facility. The control device 12 is installed, for example, in a control room adjacent to the imaging room. The control device 12 is a desktop personal computer, a notebook personal computer, or a tablet terminal. The control device 12 is operated by an operator of the CT scanner 10, such as a radiological technologist. As an example, as shown in Figure 2, the device body 11 comprises a stage 13, three support columns 14A, 14B, and 14C, and a top plate 15. The stage 13 is, for example, an octagonal flat plate (see Figure 6). Casters 16 for transport are attached to the