JP4703373B2 - X-ray computed tomography system - Google Patents

Description

  The present invention relates to an X-ray computed tomography apparatus that realizes continuous rotation by a slip ring mechanism.

  The slip ring mechanism is configured such that the power between the rotating unit on which the X-ray tube and the X-ray detector are mounted and the fixed unit having the power supply source corresponding to the X-ray tube and the signal processing unit corresponding to the X-ray detector. It is provided for transmitting signals. With the advent of this slip ring mechanism, continuous rotation scanning is possible, and now the speed is increased to about 0.5 per rotation.

  In many cases, this slip ring mechanism is shared by many types of X-ray computed tomography apparatuses due to cost performance. Therefore, multiple channels, that is, many slip rings are provided in advance so as to be compatible with high-end machines.

  Therefore, depending on the type of X-ray computed tomography apparatus, the number of slip rings may be excessively overspecified.

  An object of the present invention is to suppress an increase in cost performance and to optimize the number of slip rings of a slip ring mechanism as much as possible in an X-ray computed tomography apparatus.

The X-ray computed tomography apparatus of the present invention includes a rotating unit having an X-ray tube that generates X-rays and an X-ray detector that detects X-rays transmitted through a subject, and power supply corresponding to the X-ray tube. A fixed unit having a source and a signal processing unit corresponding to the X-ray detector, and a slip ring mechanism that transmits at least one of electric power and a signal between the rotating unit and the fixed unit, slip ring mechanism has a plurality of slip ring unit, the slip ring unit each have a structure which have a plurality of slip rings are connected to each other.

  ADVANTAGE OF THE INVENTION According to this invention, while adjusting the number of slip ring units mounted according to a X-ray computed tomography apparatus, while suppressing a raise in cost performance, the number of slip rings can be optimized as much as possible.

  The X-ray computed tomography apparatus according to the present invention will be described below with reference to the accompanying drawings. The X-ray computed tomography apparatus has a rotation / rotation type in which an X-ray tube and an X-ray detector are integrally rotated around a subject, and a large number of detection elements are arrayed in a ring shape, and only the X-ray tube is covered. There are various types such as a fixed / rotation type that rotates around the specimen, and the present invention can be applied to any of the rotation / rotation type and the fixed / rotation type. Here, the rotation / rotation type will be described. The mechanism for converting incident X-rays into electric charge is an indirect conversion type in which X-rays are converted into light by a phosphor such as a scintillator, and the light is converted into electric charge by a photoelectric conversion element such as a photodiode. The generation of electron hole pairs and their transfer to the electrode, that is, the direct conversion type utilizing a photoconductive phenomenon, is the mainstream. Any of these methods may be employed as the X-ray detection element, but here, the former indirect conversion type will be described. In recent years, so-called multi-tube type devices in which a plurality of pairs of X-ray tubes and X-ray detectors are mounted on a rotating ring have been commercialized, and peripheral technologies have been developed. The present invention can be applied to both a conventional single-tube type device and a multi-tube type device. Here, a single tube type will be described.

  FIG. 1 is a diagram schematically showing an internal configuration of a gantry of an X-ray computed tomography apparatus according to an embodiment of the present invention. The gantry 1 has a rotating part 5 and a fixed part 3. The rotating unit 5 is an annular rotation on which the X-ray tube 7 for generating X-rays, the X-ray detector 9 for detecting X-rays transmitted through the subject, and the X-ray tube 7 and the X-ray detector 9 are mounted. The body 10 and a rotation mechanism (not shown) that supports and drives the rotating body 10 are provided. A tube voltage is applied to the X-ray tube 7 from a high voltage generator, and a filament heating current is supplied. The high voltage generator includes a battery and a booster, and is mounted on the same rotating body 10 as the X-ray tube 7. The high voltage generator is electrically connected to the power supply source on the fixed portion 3 side via the slip ring mechanism 11. Thereby, the high voltage generator can continuously receive power supply from the power supply source during the rotation period. The high voltage generator is electrically connected to the X-ray control unit on the fixed unit 3 side via the slip ring mechanism 11. Thereby, the high voltage generator can continuously receive the X-ray control signal from the X-ray control unit during the rotation period.

  The X-ray detector 9 is connected to a data collection unit mounted on the same rotating body 10 as the X-ray detector 9. The data collection unit may be installed on the fixed unit 3 side. The data acquisition unit has a function of converting the output (current signal) of each channel of the X-ray detector 9 into a voltage signal, amplifying it, and converting it into a digital signal. The data collection unit is electrically connected to the data collection control unit on the fixed unit 3 side via the slip ring mechanism 11. Thereby, the data collection unit can continuously receive the data collection control signal from the data collection control unit during the rotation period. The data collection control unit may be provided not in the fixed unit 3 of the gantry 1 but in a computer unit of a console on which a reconstruction processing unit or the like is mounted. In addition, the data collection unit is electrically connected to the signal processing unit mainly for preprocessing such as logarithmic conversion processing and non-channel non-uniformity correction installed on the fixed unit 3 side through the slip ring mechanism 1. Is done. Thereby, data can be continuously transmitted from the data collection unit to the signal processing unit during the rotation period. The signal processing unit may be provided not in the fixing unit 3 of the gantry 1 but in the computer unit.

  As shown in FIG. 2, the slip ring mechanism 11 includes a plurality of slip ring units 13 having the same shape and the same structure. The plurality of slip ring units 13 are coaxially stacked and connected around the rotation axis R of the rotating body 10. As shown in FIGS. 2 and 3, the plurality of slip ring units 13 have the same number of channels, that is, the same number (n) of slip rings. For example, each slip ring unit 13 includes three slip rings 17 (n = 3). In each of the slip ring units 13, three slip rings 17 are mounted in common on a single cylindrical ring base 15. The ring pedestal 15 is attached to the rotating body 10 together with the three slip rings 17. Three brushes 19 respectively corresponding to the three slip rings 17 are held on the brush base 21. The brush base 21 is attached to an appropriate position of the fixing portion 3 so that the three brushes 19 face the three slip rings 17 respectively.

The number of slip ring units 13 (N) depends on the number of channels (M) required in the gantry configuration.
(N × N) ≧ M
And the minimum N is set. The fact that the number of slip rings included in each slip ring unit 13 is selected as 3 (n = 3) is high on the grounds that the number of devices having a gantry configuration in which the number of required channels is an integral multiple of 3 is the largest. Versatility is ensured.

  Thus, by increasing or decreasing the slip ring unit 13 having the same shape and the same structure and the same number of channels according to the required number of channels, it is possible to improve the cost merit as compared with the case where the slip ring mechanism is individually designed. Further, it is considered that the loss on the mounting space due to the generation of many unused channels by diverting the slip ring mechanism of another model can be reduced.

  In addition, although the contact system by the combination of the brush 19 and the slip ring 17 was demonstrated here as a system of the slip ring unit 13, the combination of a light emission part and a light-receiving part, or the non-contact system by an electromagnetic coil etc. is employ | adopted. good. Further, as shown in FIG. 4, a contact method and a non-contact method may be mixed in the slip ring unit 13. In the slip ring unit 13, for example, a plurality of light emitting elements are arranged in a row on one slip ring 25, and at least one light receiving element 23 is arranged in an opposing position to constitute a non-contact system. It is configured with a combination of two contact type slip rings 17 and brushes 19. The contact method is suitable for power supply, and the non-contact method is suitable for data transmission. According to the number of power lines required by the gantry 1 and the number of data transmission channels, the number of non-contact type rings and the number of contact type rings of the slip ring unit 13 can be arbitrarily set together with the number of units.

  Further, as described above, the plurality of slip ring units 13 are stacked and connected coaxially, but in order to facilitate the alignment of the stack and realize strong connection, as shown in FIG. A concave portion 18 and a convex portion 20 may be formed on the front and rear ends of the pedestal 16 of the system.

  Furthermore, as described above, the plurality of slip ring units 13 have the same shape and the same structure, and the number of channels (the number of slip rings) is also configured to be the same, thereby realizing cost merit. As shown in FIG. 6, the number of channels (slip ring number) is reduced to, for example, 2 channels and mixed with the slip ring unit 14 in which the axis lengths of the bases 26 and 28 are shortened. It can be considered that elimination of unused channels can be realized without a significant reduction in cost merit compared to the case of using only the structure.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

1 is a schematic front view of the inside of a gantry of an X-ray computed tomography apparatus according to an embodiment of the present invention. Fig. 2 is a schematic vertical sectional view of the slip ring mechanism of Fig. 1. The perspective view of the slip ring unit of FIG. The longitudinal cross-sectional schematic diagram which shows the other structure of the slip ring mechanism of FIG. The longitudinal cross-sectional schematic diagram which shows the other structure of the slip ring mechanism of FIG. The longitudinal cross-sectional schematic diagram which shows the other structure of the slip ring mechanism of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Gantry, 5 ... Rotating part, 3 ... Fixed part, 7 ... X-ray tube, 9 ... X-ray detector, 10 ... Rotating body, 11 ... Slip ring mechanism, 13 ... Slip ring unit, 15 ... Ring base, 17 ... slip ring, 19 ... brush 19, 21 ... brush pedestal.

Claims (6)

A rotating unit having an X-ray tube for generating X-rays and an X-ray detector for detecting X-rays transmitted through the subject;
A fixing unit having a power supply source corresponding to the X-ray tube and a signal processing unit corresponding to the X-ray detector;
A slip ring mechanism that transmits at least one of electric power and a signal between the rotating part and the fixed part;
The slip ring mechanism has a plurality of slip ring units,
The slip ring unit each, have a plurality of slip rings, X-rays computed tomography apparatus characterized by having a structure connected to each other.   The X-ray computed tomography apparatus according to claim 1, wherein the plurality of slip ring units have the same shape and the same structure. Wherein the plurality of ring arrangement is, X-rays computed tomography system according to claim 1 or 2, wherein the having the same number of slip rings. The X-ray computed tomography apparatus according to any one of claims 1 to 3, wherein each of the slip ring units includes three slip rings. The slip ring unit each includes a single base, X-rays computed tomography system according to claim 1, any one of 4, characterized in that it comprises a plurality of slip rings mounted on the pedestal .   The X-ray computed tomography apparatus according to claim 5, wherein the single pedestal includes a concave portion and a convex portion that are fitted to the front and rear ends to connect the plurality of slip ring units.

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