KR101140341B1 - X-ray and g-ray Hybrid Image Sensing Method and Apparatus for DTSDigital Tomosynthesis System - Google Patents

Abstract

The present invention relates to a method and apparatus for sensing X-ray and γ-ray hybrid images in a digital tomosynthesis system (DTS).
According to an aspect of the present invention, a hybrid image sensing device included in a digital tomography apparatus includes photoelectric for converting X-rays projected from an object or γ-rays emitted from a drug previously injected into the object into electrical signals. Circuitry for processing the output of the conversion means; An X-ray counter for outputting a signal corresponding to the number of photons generated in the photoelectric conversion means by the X-ray from the signal processed in the circuit; And a γ-ray counter for outputting a signal corresponding to the number of photons generated by the photoelectric conversion means by the γ-ray from the signal processed in the circuit.

Description

X-ray and γ-ray Hybrid Image Sensing Method and Apparatus for DTS (Digital Tomosynthesis System)}

The present invention relates to a method and apparatus for sensing X-ray and γ-ray hybrid images, and more particularly, to a method and apparatus for sensing X-ray and γ-ray hybrid images in a digital tomosynthesis system (DTS). It is about.

A digital tomosynthesis system (DTS) is a device that reconstructs an image in three dimensions by using projection image data acquired at multiple angles within a limited angle. DTS uses a technique of improving the accuracy of analysis and diagnosis by separating the superimposed image of the subject to be three-dimensional spatially from the two-dimensional projection image. Recently, a lot of research is being carried out to apply this technology to the field of 3D Digital Breast Tomosynthesis (DBT).

The conventional two-dimensional X-ray mammography method detects an image depending on all X-ray attenuations existing in the space from the X-ray source to the detector, so that the lesion region of interest is overlapped by an object above or below the lesion. Accurate identification of lesions was difficult. Of course, using a three-dimensional diagnostic image using a computed tomography (CT) can eliminate this overlap, but CT must be taken from many angles, and one rotation around the subject, There are many limitations in areas such as breast cancer diagnosis in terms of irradiation dose and rotation angle.

In the field of DBT using DTS technology, it is recognized as a very meaningful and highly effective diagnostic technology in that it provides three-dimensional images close to CT while solving such limitations on radiation dose and rotation angle. However, the X-ray projection image using the DTS technology provides only an anatomical image of a subject, and there are many improvements to obtain more accurate images in dense lesions such as breast tissue.

Recently, as shown in FIG. 1, X-ray projection image is acquired by the X-ray detector 120 while the X-ray source 110 is irradiated to the subject using the X-ray source 110 using the hybrid DTS, and injected into the subject in advance. Γ-rays from the prescribed drug were acquired by the γ-ray camera 130 to obtain γ-ray images, thereby combining X-ray projection images and γ-ray images to obtain X at high density areas such as breast tissue. Attempt to correct line distortion. However, since the hybrid DTS as shown in FIG. 1 should have a separate γ-ray camera 130, it increases the price of the device, and rotates the γ-ray camera 130 as well as the X-ray source 110. There is a problem that causes inconvenience in the operation of the device when trying to obtain.

Accordingly, an object of the present invention is to solve the above-described problems, and an object of the present invention is to efficiently provide for X-ray and γ-ray hybrid images through a hybrid image sensing device without a separate γ-ray camera, thereby effectively preventing lesions. The present invention provides a method and apparatus for sensing X-ray and γ-ray hybrid images of a digital tomography imaging apparatus capable of providing accurate identification.

First, to summarize the features of the present invention, according to one aspect of the present invention for achieving the object of the present invention, the hybrid image sensing device provided in the digital tomography imaging apparatus, the X-ray projected from the object Or a circuit for processing an output of photoelectric conversion means for converting gamma -rays emitted from drugs previously injected into the object into electrical signals; An X-ray counter for outputting a signal corresponding to the number of photons generated in the photoelectric conversion means by the X-ray from the signal processed in the circuit; And a γ-ray counter for outputting a signal corresponding to the number of photons generated by the photoelectric conversion means by the γ-ray from the signal processed in the circuit.

Drugs previously injected into the subject include Tc-99m sestamibi.

The circuit includes an amplifier for amplifying the output of the photoelectric conversion means; A plurality of comparators for comparing the output of said amplifier with a preset reference voltage in each; And logic for generating a first signal to be output to the X-ray counter and a second signal to be output to the γ-ray counter through a logical combination of the outputs of the plurality of comparators.

The plurality of comparators may include: a first comparator configured to compare the output of the amplifier and a first reference voltage to generate a first comparison result signal; A second comparator for comparing a output of the amplifier with a second reference voltage to generate a second comparison result signal; And a third comparator comparing the output of the amplifier with a third reference voltage to generate a third comparison result signal.

The first reference voltage is a preset first voltage corresponding to the case where the photoelectric conversion means generates a signal for γ-ray, and the second reference voltage generates the signal for the X-ray in the photoelectric conversion means. The third reference voltage corresponds to a case in which the third reference voltage corresponds to a case in which the photoelectric conversion means generates a signal for X-rays, and is a third voltage preset to be smaller than the second voltage. The first voltage may be set greater than the second voltage.

The logic may include: first means for generating the first signal that is activated according to the first comparison result signal; And second means for generating the second signal that is activated according to a logical product operation result of the second comparison result signal and the third comparison result signal.

In addition, the hybrid image sensing method in the digital tomography imaging apparatus according to another aspect of the present invention, converting the X-rays projected from the object or the γ-rays emitted from the drug previously injected into the object into an electrical signal Processing the output of one photoelectric conversion means; Outputting a signal corresponding to the number of photons generated by the photoelectric conversion means by the X-rays; And outputting a signal corresponding to the number of photons generated by the photoelectric conversion means by the γ-rays.

According to the X-ray and γ-ray hybrid image sensing method and apparatus of the digital tomography imaging apparatus according to the present invention, by providing an X-ray and γ-ray hybrid image through a hybrid image sensing device without a separate γ-ray camera, It can efficiently provide accurate identification of lesions.

1 is a view for explaining a general hybrid digital tomography apparatus.
FIG. 2 is a diagram for describing a hybrid image sensing device of a digital tomography apparatus according to an embodiment of the present invention.
FIG. 3 is a diagram for describing a photographing method at multiple angles of FIG. 3.
4 is a block diagram of the hybrid image sensing device of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout.

2 is a diagram for describing a hybrid image sensing device 12 of the digital tomography apparatus 10 according to an embodiment of the present invention.

In the digital tomography apparatus 10 according to an embodiment of the present invention, a 3D image reconstruction algorithm may be used for diagnosing breast cancer, and the diagnostic subject (for example, moving the X-ray source 11 at various angles). X-rays are projected onto the breast, and the planar two-dimensional hybrid image sensing device 12 may be used to take a method similar to the Cone-beam image reconstruction algorithm for capturing X-ray images from multiple angles. In addition, in order to be able to provide γ-ray images without a separate γ-ray camera, the hybrid image sensing device 12 may release γ released from a drug (eg, Tc-99m sestamibi) previously injected into the object. By acquiring -ray images, X-ray images and γ-ray images can be combined and analyzed to efficiently provide accurate identification of lesions.

As shown in FIG. 3, in the case of A and B portions, two lesion states are shown as superimposed images when taken in direction 2, and when taken in direction 1, lesions of site A appear on the left side of the projection image and in direction 3 At the time of shooting, lesions in the B region appear on the left side of the projection image. The DTS technology of the digital tomography apparatus 10 separates and analyzes an object into three-dimensional space through an X-ray image that is superimposed on a two-dimensional projection image acquired from multiple angles through the hybrid image sensing device 12. This allows accurate diagnosis of the location and condition of the three-dimensional lesions. In the digital tomography apparatus 10 of the present invention, the γ-ray image may be simultaneously provided through the hybrid image sensing device 12 to assist in diagnosis through the analysis of the X-ray image.

4 is a block diagram of the hybrid image sensing device 12 of FIG. 2.

Referring to FIG. 4, the hybrid image sensing device 12 according to an exemplary embodiment of the present invention includes a photodiode formed in the form of a photoelectric conversion means, that is, a complementary MOS (CMOS) or a charge coupled device (CCD). Photo diode: processes the signal output through the PD). The photodiode PD may convert and output X-rays projected from the object or γ-rays emitted from a drug (eg, Tc-99m sestamibi) previously injected into the object into an electrical signal.

The hybrid image sensing device 12 includes an amplifier 42, a first comparator 43, a second comparator 44, a third comparator 45, a logic 46, an X-ray counter 47, and γ- A line counter 48.

The amplifier 42, the first comparator 43, the second comparator 44, the third comparator 45, and the logic 46 process an output signal from the photodiode PD to form an X-ray counter ( 47 and a signal to be output to the gamma-ray counter 48.

The amplifier 42 amplifies the weak signal from the photodiode PD and amplifies it into a signal of a size appropriate for processing at a later stage.

The first comparator 43, the second comparator 44, and the third comparator 45 compare the output of the amplifier 42 with the preset reference voltages VREF1 / VREF2 / VREF3, respectively.

The first comparator 43 compares the output of the amplifier 42 with the first reference voltage VREF1 to generate a first comparison result signal. For example, the first reference voltage VREF1 is a preset first voltage corresponding to the case where the photodiode PD generates a signal for? -Line. That is, the first reference voltage VREF1 may emit γ-rays from a drug (eg, Tc-99m sestamibi) previously injected into the subject, and the energy of the γ-rays is about 140-keV, and the photo When the diode PD generates photons such as visible light and outputs an electrical signal, the voltage is set by assuming a voltage corresponding thereto.

The second comparator 44 compares the output of the amplifier 42 with the second reference voltage VREF2 to generate a second comparison result signal. For example, the second reference voltage VREF2 is a preset second voltage corresponding to the case where the photodiode PD generates a signal for the X-ray. That is, when the X-rays emitted from the X-ray source 11 are projected through the object, the second reference voltage VREF2 has an energy of about 20 to 30 keV at this time and 30 keV at the photodiode PD. When a photon such as visible light corresponding to a degree is generated to output an electrical signal, the voltage is set assuming a corresponding voltage.

The third comparator 45 compares the output of the amplifier 42 with the third reference voltage VREF3 to generate a third comparison result signal. For example, the third reference voltage VREF3 is a preset third voltage corresponding to the case where the photodiode PD generates a signal for the X-ray. That is, when the X-rays emitted from the X-ray source 11 are projected through the object, the third reference voltage VREF3 has the energy of the X-rays of about 20 to 30 keV and 20 in the photodiode PD. When a photon such as visible light corresponding to energy between keV and 30keV is generated and an electrical signal is output, the voltage is set assuming a corresponding voltage.

In the above, the second reference voltage VREF2 may be set larger than the third reference voltage VREF3, and the first reference voltage VREF1 may be set larger than the second reference voltage VREF2. However, the present invention is not limited thereto, and sizes of the reference voltages VREF1, VREF2, and VREF3 may be appropriately set in other manners according to the circuit configuration.

Meanwhile, the logic 46 may output the first signal to be output to the X-ray counter 47 and the γ-ray counter 48 through logic combinations of the outputs of the plurality of comparators 43, 44, and 45. Generate a second signal. For example, the logic 46 bypasses or buffers the first comparison result signal generated from the first comparator 43 to generate a signal that is active in accordance with the first comparison result signal to generate the γ-line counter 48. Can be printed as In addition, the logic 46 may use a logic to perform an AND operation on the second comparison result signal generated from the second comparator 44 and the third comparison result signal generated from the third comparator 45 to generate a second comparison result signal. According to the result of the AND operation of the third comparison result signal can be generated and output to the X-ray counter 47.

The γ-ray counter 48 counts the active number (eg, the number of logic high pulses) of the signal that is activated according to the first comparison result signal generated from the logic 46 as above, thereby providing the γ-ray counter as described above. As a result, a signal corresponding to the number of photons generated by the photodiode PD may be output.

The X-ray counter 47 is an active number of the active signal according to the logical product operation result of the second comparison result signal and the third comparison result signal generated from the logic 46 as described above (eg, Number), a signal corresponding to the number of photons generated by the photodiode PD by the X-rays as described above can be output.

Accordingly, the signals output from the X-ray counter 47 and the γ-ray counter 48 are processed by a predetermined processor, so that an X-ray image, a γ-ray image, or a combination thereof necessary for the screen of a display means such as an LCD is processed. It can provide images. The γ-ray image can assist in diagnosis through analysis of the X-ray image, thereby enabling a more accurate diagnosis of the location and condition of the three-dimensional lesion.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

X-ray source (11)
Hybrid Image Sensing Device (12)
Amplifier (42)
First comparator 43
Second Comparator (44)
Third Comparator (45)
Logic (46)
X-Ray Counter (47)
γ-ray counter (48)

Claims (7)

A hybrid image sensing device provided in a digital tomography imaging apparatus,
A circuit for processing an output of photoelectric conversion means for converting X-rays projected from an object or γ-rays emitted from a drug previously injected into the object into an electrical signal; An X-ray counter for outputting a signal corresponding to the number of photons generated in the photoelectric conversion means by the X-ray from the signal processed in the circuit; And a γ-ray counter for outputting a signal corresponding to the number of photons generated in the photoelectric conversion means by the γ-ray from the signal processed in the circuit.
The circuit is,
An amplifier for amplifying the output of the photoelectric conversion means; A plurality of comparators for comparing the output of the amplifier and a preset reference voltage to each; And logic for generating a first signal to be output to the X-ray counter and a second signal to be output to the γ-ray counter through a logical combination of the outputs of the plurality of comparators. Device. The method of claim 1,
Drugs pre-injected into the subject include Tc-99m sestamibi Hybrid image sensing device, characterized in that. delete The method of claim 1,
The plurality of comparators,
A first comparator for comparing the output of the amplifier with a first reference voltage to generate a first comparison result signal;
A second comparator for comparing a output of the amplifier with a second reference voltage to generate a second comparison result signal; And
A third comparator comparing the output of the amplifier with a third reference voltage to generate a third comparison result signal;
Hybrid image sensing device comprising a. The method of claim 4, wherein
The first reference voltage is a preset first voltage corresponding to the case where the photoelectric conversion means generates a signal for γ-line,
The second reference voltage is a preset second voltage corresponding to the case where the photoelectric conversion means generates a signal for X-rays,
The third reference voltage is a third voltage which is preset to be smaller than the second voltage corresponding to the case where the photoelectric conversion means generates a signal for the X-ray,
And the first voltage is set higher than the second voltage. The method of claim 4, wherein
The logic is,
First means for generating the first signal that is activated according to the first comparison result signal; And
Second means for generating the second signal that is activated according to a logical product operation result of the second comparison result signal and the third comparison result signal
Hybrid image sensing device comprising a. A hybrid image sensing method in a digital tomography imaging apparatus,
Processing the output of one photoelectric conversion means for converting X-rays projected from the object or γ-rays emitted from a drug previously injected into the object into an electrical signal;
Outputting a signal corresponding to the number of photons generated by the photoelectric conversion means by the X-rays; And
Outputting a signal corresponding to the number of photons generated by the photoelectric conversion means by the? -Rays;
Hybrid image sensing method comprising a.

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