CN215739035U - Calibration target and medical imaging system - Google Patents
Calibration target and medical imaging system Download PDFInfo
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- CN215739035U CN215739035U CN202122373776.6U CN202122373776U CN215739035U CN 215739035 U CN215739035 U CN 215739035U CN 202122373776 U CN202122373776 U CN 202122373776U CN 215739035 U CN215739035 U CN 215739035U
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Abstract
The utility model provides a calibration target and a medical imaging system, wherein the calibration target comprises a calibration target substrate and a plurality of marker bodies embedded in the calibration target substrate; the calibration target substrate comprises a first calibration target substrate and a second calibration target substrate, and the plurality of mark bodies comprise a plurality of first mark bodies embedded in the first calibration target substrate and a plurality of second mark bodies embedded in the second calibration target substrate; wherein the total number of the plurality of first markers is greater than or equal to a first threshold number. The utility model increases the number of the first mark bodies, thereby improving the calibration precision of the calibration by the calibration target and reducing the installation precision requirement of the calibration target.
Description
Technical Field
The utility model relates to the technical field of calibration, in particular to a calibration target and a medical imaging system.
Background
The medical imaging system such as a C-arm imaging system, a CT machine and the like is one of large medical equipment commonly used in hospitals at present, can generate a tomographic image in real time in an operation, and can help doctors to diagnose in time and monitor the operation condition in the operation. The medical imaging system needs to be registered before use, and in the registration, the most central and critical step is to calibrate the medical imaging system. The medical imaging system is calibrated by means of a calibration target, and internal and external parameters of the medical imaging system are finally obtained through the space three-dimensional coordinates of the marking points on the calibration target and the pixel two-dimensional coordinates of the marking points in the X-ray image.
The existing calibration target generally adopts a metal sphere as a marker body, the marker body forms a geometric structure with three-dimensional space distribution through the support of a calibration target body, the calibration target receives the radiation irradiation emitted by a radioactive source, the attenuated image information is obtained on an imaging detector, the three-dimensional space coordinate of the marker body is determined through an optical tracking system, and calibration is carried out according to the three-dimensional space coordinate of the marker body, the geometric projection relation between the radioactive source and the imaging detector plane and the projection information.
The existing calibration target mainly has the following problems: the number of the mark bodies on the calibration target is small, so that when the optical tracking system fluctuates, errors caused by three-dimensional space coordinates of the mark bodies are increased, and the calibration precision is low; meanwhile, when the number of the markers is small, in order to avoid influencing the calibration precision, the plane where the markers are located is required to be perpendicular to the optical axis of the radioactive source as much as possible (namely, the mounting precision requirement of the calibration target is high), so that the markers are not shielded or overlapped in imaging, and the mounting precision requirement of the calibration target is high.
SUMMERY OF THE UTILITY MODEL
In view of the above, it is necessary to provide a calibration target and a medical imaging system, so as to solve the technical problems of the prior art that the calibration precision is low and the requirement for the installation precision of the calibration target is high.
In one aspect, the present invention provides a calibration target, including a calibration target substrate and a plurality of marker bodies embedded in the calibration target substrate;
the calibration target substrate comprises a first calibration target substrate and a second calibration target substrate, and the plurality of mark bodies comprise a plurality of first mark bodies embedded in the first calibration target substrate and a plurality of second mark bodies embedded in the second calibration target substrate;
the total number of the first marker bodies is greater than or equal to the first threshold number, so that the calibration precision is ensured.
In some possible implementations, a total number of the plurality of first token bodies is less than or equal to a second threshold number.
In some possible implementations, the first calibration target substrate includes a first calibration target plate, a second calibration target plate, and at least one connecting plate, the first calibration target plate and the second calibration target plate are disposed opposite to each other, two sides of the at least one connecting plate are respectively connected to the first calibration target plate and the second calibration target plate, and the plurality of first mark bodies include a plurality of first sub mark bodies embedded in the first calibration target plate and a plurality of second sub mark bodies embedded in the second calibration target plate.
In some possible implementations, the diameters of each of the plurality of first sub-taggants are the same, and the diameters of each of the plurality of second sub-taggants are the same;
the diameter of each first sub-label is different from the diameter of each second sub-label.
In some possible implementations, the diameter of each first sub-label is 1.5mm to 2.5mm, and the diameter of each second sub-label is 2.5mm to 3.5 mm.
In some possible implementations, the first calibration target plate is parallel to the second calibration target plate.
In some possible implementations, the distance between the first calibration target plate and the second calibration target plate is 50mm to 100 mm.
In some possible implementations, a total number of the plurality of first sub-taggants is different from a total number of the plurality of second sub-taggants.
In some possible implementations, the plurality of first sub-markers are staggered with the plurality of second sub-markers along the orthographic projection direction of the first calibration target plate.
In some possible implementations, the calibration target further includes at least one first recognition object embedded in the first calibration target plate and at least one second recognition object embedded in the second calibration target plate, a diameter of the at least one first recognition object is the same as a diameter of each first sub-marker, and a diameter of the at least one second recognition object is the same as a diameter of each second sub-marker.
In some possible implementations, the attenuation degrees of the first sub-markers in the plurality of first sub-markers are the same, the attenuation degrees of the second sub-markers in the plurality of second sub-markers are also the same, the attenuation degrees of the first sub-markers are different from the attenuation degrees of the second sub-markers, and the attenuation degrees of the first sub-markers and the attenuation degrees of the second sub-markers are both greater than the attenuation degree of the calibration target substrate.
On the other hand, the utility model also provides a medical imaging system, which comprises a radioactive source, an imaging detector, a human body objective table arranged between the radioactive source and the imaging detector and the calibration target in any one of the possible implementation manners; the area formed by rays emitted by the radioactive source is a scanning area, the first calibration target substrate is positioned in the scanning area, and the second calibration target substrate is positioned outside the scanning area.
The beneficial effects of adopting the above embodiment are: according to the calibration target provided by the utility model, the number of the first marking bodies embedded in the first calibration target substrate is larger than the first threshold number, so that the error introduced by the self-space three-dimensional coordinates of the first marking bodies can be reduced, and the calibration precision of calibration through the calibration target is improved. Furthermore, due to the fact that the number of the first mark bodies is increased, even if the plane where the mark bodies are located is not perpendicular to the optical axis of the radioactive source, and partial mark bodies are shielded or overlapped in imaging, calibration precision of calibration through the calibration target cannot be influenced, and the requirement for installation precision of the calibration target is lowered.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a schematic structural diagram of an embodiment of a calibration target provided by the present invention;
FIG. 2 is a schematic structural diagram of an embodiment of a medical imaging system provided by the present invention;
FIG. 3 is a schematic structural diagram of a first calibration target plate according to an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of a first calibration target plate according to another embodiment of the present invention;
FIG. 5 is a schematic structural diagram of an embodiment of a distribution of a plurality of markers according to the present invention;
FIG. 6 is a schematic structural diagram illustrating an arrangement of a first recognition entity according to an embodiment of the present invention;
FIG. 7 is a schematic structural diagram of a first arrangement of a first recognition entity and a second recognition entity according to an embodiment of the present invention;
FIG. 8 is a schematic structural diagram illustrating a second arrangement of a first recognition entity and a second recognition entity according to an embodiment of the present invention;
fig. 9 is a schematic structural diagram of an embodiment of another application scenario of the medical imaging system provided by the present invention.
Detailed Description
The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the utility model, and not restrictive of the full scope of the utility model. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the embodiments of the present invention, "a plurality" means two or more unless otherwise specified. "and/or" describes the association relationship of the associated objects, meaning that three relationships may exist, for example: a and/or B, may represent: a exists alone, A and B exist simultaneously, and B exists alone.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the utility model. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.
The utility model provides a calibration target and a medical imaging system, which are respectively explained below.
In some embodiments of the present invention, as shown in FIG. 1, the calibration target 100 includes a calibration target substrate 110 and a plurality of marker bodies 120 embedded in the calibration target substrate 110;
the alignment target substrate 110 includes a first alignment target substrate 111 and a second alignment target substrate 112, and the plurality of mark bodies 120 includes a plurality of first mark bodies 121 embedded in the first alignment target substrate 111 and a plurality of second mark bodies 122 embedded in the second alignment target substrate 112;
wherein, the total number of the plurality of first markers 121 is greater than or equal to the first threshold number.
Compared with the prior art, in the calibration target 100 provided by the embodiment of the utility model, by setting the number of the first mark bodies 121 embedded in the first calibration target substrate 111 to be greater than the first threshold number, the error introduced by the three-dimensional space coordinates of the first mark bodies can be reduced, and the calibration precision of the calibration through the calibration target 100 is further improved. Further, due to the increase of the number of the first markers 121, even if the plane of the markers 121 is not perpendicular to the optical axis of the radiation source 200, and the part of the markers 121 in imaging is blocked or overlapped, the calibration accuracy of the calibration by the calibration target 100 will not be affected, and the requirement of the installation accuracy of the calibration target 100 is reduced.
Since the calibration target 100 is used for calibrating the imaging of the medical imaging system, but the markers on the calibration target 100 are not all involved in calibration, only the markers located in the scanning region formed by the medical imaging system are involved in calibration, in some embodiments of the present invention, as shown in fig. 1, the first calibration target substrate 111 is configured to be located in the scanning region 11, and the second calibration target substrate 112 is configured to be located outside the scanning region 11.
By arranging the first calibration target substrate 111 in the scanning region 11, the number of first marker 121 can be reduced while ensuring the calibration accuracy.
The scanning region 11 is a region generated by the medical imaging system during scanning, and specifically, as shown in fig. 2, is a schematic structural diagram of an embodiment of the medical imaging system provided by the embodiment of the present invention. The medical imaging system 10 includes: demarcate target 100, radiation source 200, formation of image detector 300 and human objective table 400, human objective table 400 is used for placing the human body that waits to detect, and human objective table 400 sets up between radiation source 200 and formation of image detector 300, and demarcation target 100 sets up between human objective table 400 and formation of image detector 300 for demarcate medical imaging system 10, specifically: the radiation source 200 is used for emitting rays, and the imaging detector 300 is used for receiving transmitted rays emitted by the radiation source 200 after the rays are transmitted through the human body to be detected and the calibration target 100, and detecting the amplitude of the transmitted rays after the rays are transmitted through the human body to be detected and the calibration target 100. Wherein, the scanning area 11 refers to the area formed by the radiation emitted by the radiation source 200, it can be understood that the intersecting area of the scanning area 11 and the calibration target 100 will vary with the position of the calibration target 100.
It should be noted that: in one particular embodiment, medical imaging system 10 is a C-arm imaging system and radiation source 200 emits X-rays.
It should be understood that: the calibration target 100 in the embodiment of the present invention may have any shape, such as a rectangular parallelepiped, a cube, a cylinder, a polygonal prism, and the like.
It should be noted that: in order to improve the convenience of embedding the marker 120 into the calibration target substrate 110, in some embodiments of the present invention, the way of embedding the marker 120 into the calibration target substrate 110 is a semi-embedding way, and in order to avoid the marker 120 from falling off from the calibration target substrate 110, a special glue is used to adhere and fix the marker 120 and the calibration target substrate 110.
It should also be noted that: to further improve the calibration accuracy of the target 100, in some embodiments of the present invention, the plurality of markers 120 do not lie entirely in the same plane.
In the embodiment of the utility model, the plurality of mark bodies 120 are not completely positioned on the same plane, so that the plurality of mark bodies 120 are distributed in three dimensions, and the calibration precision of the calibration through the calibration target 100 is further improved.
In a preferred embodiment of the present invention, the first threshold number is 32.
By setting the number of the first threshold values to be 32, the calibration error of the calibration target 100 can be smaller than or equal to 1mm, and higher calibration precision is achieved.
In order to improve the calibration accuracy, the contrast between the radiation transmitted through the calibration target substrate 110 and the radiation transmitted through the marker 120 should be improved, so that the projection of the marker 120 on the imaging detector 300 is easier to obtain. In addition, in order to avoid the influence of the calibration target substrate 110 on the projection of the human body to be detected on the imaging detector 300, the attenuation degree of the radiation emitted by the radiation source 200 by the marker 120 is greater than the attenuation degree of the radiation emitted by the radiation source 200 by the calibration target substrate 110.
Specifically, the method comprises the following steps: the index body 120 is made of a material having a high attenuation property to radiation, and the calibration target substrate 110 is made of a material having a low attenuation property to radiation. Specifically, the marker body 120 may be made of any one of tungsten carbide, stainless steel, or gold. The calibration target substrate 110 may be made of any one of poly (methyl methacrylate), PMMA), polystyrene, plastic, ceramic, and Polyetheretherketone (PEEK).
Further, since the calibration target 100 needs to be sterilized before use, in one embodiment of the present invention, the marker body 120 is made of stainless steel and the calibration target substrate 110 is made of PEEK.
This is because PEEK has a low density and stable material properties, and the structure and properties of PEEK are not changed after sterilization, which is suitable for the medical imaging system 10 according to the embodiment of the present invention. The use of a marker body 120 made of stainless steel may reduce the cost of calibrating the target 100.
Further, since the rays emitted by the radiation source 200 pass through the human body to be detected and the calibration target 100 and then are imaged on the imaging detector 300, and calibration is realized by analyzing the imaging, in order to avoid that too many first marker bodies 121 block the effective area of the human body to be detected imaged on the imaging detector 300, in some embodiments of the present invention, the total number of the first marker bodies 121 is less than or equal to the second threshold number.
By setting the total number of the first marker bodies 121 to be less than or equal to the second threshold number, it can be avoided that the number of the first marker bodies 121 is too large to block the effective area of the human body to be detected imaged on the imaging detector 300, and the accuracy of detecting the human body to be detected is improved.
In a preferred embodiment of the utility model, the second threshold number is 60.
This is due to: although the calibration accuracy is improved as the total number of the first marker bodies 121 increases, when the total number of the first marker bodies 121 is greater than 60, the calibration accuracy approaches a constant value, and therefore, by setting the total number of the first marker bodies 121 to be not greater than 60, the calibration accuracy is improved, shielding is avoided, and the manufacturing cost of the calibration target 100 can be reduced.
In some embodiments of the present invention, as shown in fig. 3, the first calibration target substrate 111 includes a first calibration target plate 1111, a second calibration target plate 1112, and at least one connection plate 1113, the first calibration target plate 1111 and the second calibration target plate 1112 are disposed opposite to each other, two sides of the at least one connection plate 1113 are respectively connected to the first calibration target plate 1112 and the second calibration target plate 1113, and the plurality of first marker bodies 121 include a plurality of first sub marker bodies 1211 embedded in the first calibration target plate 1111 and a plurality of second sub marker bodies 1212 embedded in the second calibration target plate 1112.
Specifically, the first calibration target substrate 111 is a hollow structure surrounded by the first calibration target plate 1111, the second calibration target plate 1112 and at least one connecting plate 1113, which can further reduce the attenuation of the first calibration target substrate 111 to the radiation emitted from the radiation source 200 and further improve the contrast between the first calibration target substrate 111 and the radiation transmitted through the first sub-marker 1211 compared to the solid structure of the first calibration target substrate 111 in the prior art, thereby further improving the calibration accuracy of the calibration through the calibration target 100. Meanwhile, the weight of the calibration target 100 can be reduced, and the installation difficulty of the calibration target 100 is further reduced.
In some embodiments of the present invention, in order to further simplify the structure of the first calibration target plate 111, as shown in fig. 3, the connecting plate 1113 includes a connecting plate body 11131 and at least one lightening hole 11132 opened on the connecting plate body 11131.
It should be understood that: the shape and size of the lightening hole 11132 can be adjusted according to the shape and size of the connecting plate body 11131, specifically, the shape of the lightening hole 11132 may be any one of a circle, a rectangle, a rounded rectangle and the like, and details are not repeated here.
Further, the calibration target 100 may be fixedly connected to the imaging detector 300 or an external fixing device through the lightening hole 11132, so as to fix the calibration target 100 between the human body stage 400 and the imaging detector 300.
In one specific embodiment, the calibration target 100 is fixed in the following manner: a flange or a handle is arranged at the lightening hole 11132, and the calibration target 100 is fixed by a mechanical arm or a hand.
In some embodiments of the present invention, in order to simplify the structure of the first calibration target substrate 111, as shown in fig. 4, the first calibration target substrate 111 includes a first calibration target plate 1111, a second calibration target plate 1112, and a connection plate 1113, and both ends of the connection plate 1113 are respectively connected to the first calibration target plate 1111 and the second calibration target plate 1112.
It should be noted that: in some embodiments of the present invention, in order to ensure the stability of the first calibration target substrate 111, the number of the connection plates 1113 may be increased appropriately, for example: the first calibration target plate 1111 and the second calibration target plate 1112 can be connected by two, three or four connecting plates 1113, which are not described in detail herein.
It should also be understood that: the second calibration target substrate 112 has the same structure as the first calibration target substrate 111, and the second marker 122 has the same structure as the first marker 121.
In the above embodiment, the first calibration target plate 1111 is parallel to the second calibration target plate 1112, and the first calibration target plate 1111 is parallel to the second calibration target plate 1112, so that the influence of the angle between the first calibration target plate 1111 and the second calibration target plate 1112 on the first subtag 1211 and the second subtag 1212 is not required to be considered, and the arrangement of the first subtag 1211 and the second subtag 1212 is facilitated.
In other embodiments of the present invention, the first calibration target plate 1111 is not parallel to the second calibration target plate 1112, and by disposing the first calibration target plate 1111 not parallel to the second calibration target plate 1112, the number of the first sub-markers 1211 and/or the second sub-markers 1212 in the direction perpendicular to the first calibration target plate 1111 can be increased, so as to further improve the calibration accuracy of the calibration target 100.
Further, since the marker 120 is projected to the imaging detector 300 from multiple angles during the calibration process, in order to avoid that the marker 120 cannot be effectively identified due to different shapes of the marker 120 projected on the imaging detector 300 from different angles, in some embodiments of the present invention, the first marker 121 and the second marker 122 are both spheres, that is: the plurality of first sub-mark bodies 1211 and the plurality of second sub-mark bodies 1212 are each a sphere.
By arranging the first marker 121 and the second marker 122 to be both spheres, because the projections of the spheres from different angles are close to circles, the first marker 121 and the second marker 122 can be easily identified, and the calibration accuracy of the calibration target 100 is further improved.
Since the first sub marker 1211, the second sub marker 1212 and the human body to be detected are projected onto the imaging detector 300 by the ray, in order to avoid the tissue of the human body to be detected from affecting the identification of the first sub marker 1211 and the second sub marker 1212, in some embodiments of the present invention, the diameters of the first sub marker 1211 in the plurality of first sub marker 1211 are the same, and the diameters of the second sub marker 1212 in the plurality of second sub marker 1212 are the same.
Through the above arrangement, the first sub marker 1211 and the second sub marker 1212 are prevented from being affected by the tissue of the human body to be detected, so that the first sub marker 1211 and the second sub marker 1212 can be easily identified.
Further, since the coordinates on the imaging detector 300 are two-dimensional coordinates when the first sub marker 1211 and the second sub marker 1212 are projected onto the imaging detector 300 through the ray, in order to distinguish the first sub marker 1211 and the second sub marker 1212 on the imaging detector 300, in some embodiments of the present invention, the diameter of the first sub marker 1211 is different from the diameter of the second sub marker 1212.
When the diameter of the first sub marker 1211 is different from the diameter of the second sub marker 1212, the areas of the first sub marker 1211 and the second sub marker 1212 projected on the imaging detector 300 are different, and the first sub marker 1211 and the second sub marker 1212 can be identified by distinguishing the areas.
In some embodiments of the utility model, the first subtag 1211 has a diameter of 1.5mm to 2.5mm and the second subtag 1212 has a diameter of 2.5mm to 3.5 mm.
By setting the diameter of the first sub marker 1211 to be 1.5mm-2.5mm and the diameter of the second sub marker 1212 to be 2.5mm-3.5mm, the volumes of the first sub marker 1211 and the second sub marker 1212 can be reduced while ensuring that the first sub marker 1211 and the second sub marker 1212 are easily recognized on the imaging detector 300, thereby saving material.
In a preferred embodiment of the present invention, the diameter of the first subtag 1211 is 2mm, and the diameter of the second subtag 1212 is 3 mm.
The legibility of the first subtag 1211 and the second subtag 1212 can be further improved by setting the diameter of the first subtag 1211 to 2mm and the diameter of the second subtag 1212 to 3 mm.
In other embodiments of the present invention, the resolution of the first subtag 1211 and the second subtag 1212 on the imaging detector 300 is achieved by: the attenuation degrees of the first sub-markers 1211 in the plurality of first sub-markers 1211 are the same, the attenuation degrees of the second sub-markers 1212 in the plurality of second sub-markers 1212 are the same, and the attenuation degrees of the first sub-markers 1211 and the attenuation degrees of the second sub-markers 1212 are different.
When the attenuation degree of the first sub marker 1211 is different from the attenuation degree of the second sub marker 1212, the gray levels of the first sub marker 1211 and the second sub marker 1212 projected on the imaging detector 300 are different, and the first sub marker 1211 and the second sub marker 1212 can be identified by distinguishing the gray levels.
It should be understood that: when the calibration target 100 in the embodiment of the present invention is used for the radiation source 200 to emit X-rays, the attenuation of the first sub-marker 1211 and the attenuation of the second sub-marker 1212 refer to the attenuation of the X-rays. The same principle is that: when the radiation emitted from the radiation source 200 is other types of radiation (e.g., alpha-ray, gamma-ray), the attenuation of the first sub-marker 1211 and the attenuation of the second sub-marker 1212 are the same for other types of radiation.
In an embodiment of the present invention, the calibration target substrate 110 is rectangular, and in order to further improve the calibration accuracy of the calibration by the calibration target 100, in some embodiments of the present invention, as shown in fig. 5, in the orthographic projection direction of the first calibration target plate 1111, the first calibration target plate 1111 and the second calibration target plate 1112 are overlapped, and the plurality of first sub-markers 1211 are arranged on the first calibration target plate 1111 in a matrix array, and the plurality of second sub-markers 1212 are arranged on the second calibration target plate 1112 in a rectangular array.
Namely: the plurality of first sub-markers 1211 are uniformly distributed on the first calibration target plate 1111, the plurality of second sub-markers 1212 are uniformly distributed on the second calibration target plate 1112, and the plurality of first sub-markers 1211 are symmetrical with respect to the symmetry axis of the first calibration target plate 1111; the plurality of second sub-label bodies 1212 are symmetrical about the second calibration target plate 1112.
The plurality of first sub marker 1211 is arranged on the first calibration target plate 1111 in a rectangular array manner, and the plurality of second sub marker 1212 is arranged on the second calibration target plate 1112 in a rectangular array manner, so that the calibration accuracy of the calibration target 100 can be improved compared with other arrangement manners.
It should be understood that: in some other embodiments of the present invention, when the calibration target substrate 110 is circular, the plurality of first sub-markers 1211 are distributed on the first calibration target plate 1111 in a circular array, and the plurality of second sub-markers 1212 are also distributed on the second calibration target plate 1112 in a circular array.
In a preferred embodiment of the present invention, in order to avoid the mutual shielding or overlapping of the projections of the plurality of first sub marker bodies 1211 and the plurality of second sub marker bodies 1212 on the imaging detector 300, as shown in fig. 5, the plurality of first sub marker bodies 1211 and the plurality of second sub marker bodies 1212 are arranged alternately along the forward projection direction of the first calibration target plate 1111. Namely: along the orthographic projection direction of the first calibration target plate 1111, the plurality of first sub marker 1211 and the plurality of second sub marker 1212 do not overlap.
By arranging that the plurality of first sub marker 1211 and the plurality of second sub marker 1212 do not overlap along the orthographic projection direction of the first calibration target plate 1111, the projections of the plurality of first sub marker 1211 and the plurality of second sub marker 1212 on the imaging detector 300 can be prevented from being blocked or overlapped with each other, and the calibration accuracy is further improved.
It should be understood that: in order to simultaneously achieve the uniform distribution of the plurality of first marker bodies 1211 and the plurality of second marker bodies 1212, and the plurality of first sub marker bodies 1211 and the plurality of second sub marker bodies 1212 are arranged in a staggered manner, in some embodiments of the present invention, the total number of the plurality of first sub marker bodies 1211 is different from the total number of the plurality of second sub marker bodies 1212.
In a preferred embodiment of the present invention, the total number of the plurality of first subtags 1211 is 16, and the total number of the plurality of second subtags 1212 is 25.
In the calibration process, the three-dimensional coordinates of the marker 120 correspond to the two-dimensional coordinates of the marker 120 on the imaging detector 300 after being scanned by the radiation source 200, so that it is necessary to identify the two-dimensional coordinates of each marker 120 and each marker 120 on the imaging detector 300. Namely: after the first sub-marker 1211 and the second sub-marker 1212 are identified through the above embodiments, the plurality of first sub-markers 1211 and the plurality of second sub-markers 1212 need to be identified.
In some embodiments of the present invention, as shown in fig. 5, the calibration target 100 further includes at least one first recognition object 130 embedded in the first calibration target plate 1111 and at least one second recognition object 140 embedded in the second calibration target plate 1112, wherein the diameter of the at least one first recognition object 130 is the same as the diameter of the first sub-mark object 1211, and the diameter of the at least one second recognition object 140 is the same as the diameter of the second sub-mark object 1212.
In an embodiment of the present invention, as shown in fig. 5, the plurality of first subtags 1211 and the plurality of second subtags 1212 respectively perform identification, that is: the calibration target 100 includes at least three first recognition objects 130 embedded in a first calibration target plate 1111 and at least three second recognition objects 140 embedded in a second calibration target plate 1112.
Specifically, the method comprises the following steps: the at least three first recognition objects 130 include at least one first recognition ball 131 and at least two second recognition balls 132, and the at least one first recognition ball 131 is disposed in a first direction a, and the at least two second recognition balls 132 are disposed in a second direction B, the first direction a being perpendicular to the second direction B. The first two-dimensional coordinate system is formed by the at least one first recognition ball 131 and the at least two second recognition balls 132, and the plurality of first sub mark bodies 1211 can be confirmed one by one through the first two-dimensional coordinate system.
It should be understood that: in order to avoid the first and second directions from being indistinguishable, the number of the first recognition balls 131 is different from that of the second recognition balls 132. Meanwhile, the first calibration target plate 1111 includes a first side a and a second side B perpendicular to each other, and the first direction a is parallel to the first side a, and the second direction B is parallel to the second side B.
In order to avoid that the first recognition ball 131 and/or the second recognition ball 132 are/is blocked by the human body to be detected when the radiation emitted by the radiation source 200 scans along different angles, so that an effective first two-dimensional coordinate system cannot be established, in an embodiment of the present invention, as shown in fig. 5, the at least three first recognition objects 130 include three first recognition balls 131 arranged in the first direction a and two second recognition balls 132 arranged in the second direction B.
In order to avoid the occlusion of the effective region of the human body to be detected when the number of the first recognition objects 130 is too large, in an embodiment of the present invention, as shown in fig. 6, at least three first recognition objects 130 include two first recognition balls 131 arranged in the first direction a and one second recognition ball 132 arranged in the second direction B.
Similarly, the at least three second recognition objects 140 include at least one third recognition ball 141 and at least two fourth recognition balls 142, and the at least one third recognition ball 141 is disposed in the first direction a, and the at least two fourth recognition balls 142 are disposed in the second direction B. The second two-dimensional coordinate system is formed by the at least one third recognition ball 141 and the at least two fourth recognition balls 142, and the plurality of second sub flag bodies 1212 can be confirmed one by one through the second two-dimensional coordinate system.
It should be understood that: in order to avoid the first and second directions from being indistinguishable, the number of the third recognition balls 141 and the fourth recognition balls 142 is different.
In order to avoid that the third recognition ball 141 and/or the fourth recognition ball 142 are/is blocked by the human body to be detected when the radiation emitted by the radiation source 200 scans along different angles, so that an effective second two-dimensional coordinate system cannot be established, in an embodiment of the present invention, as shown in fig. 5, the at least three second recognition objects 140 include three third recognition balls 141 arranged in the first direction a and two fourth recognition balls 142 arranged in the second direction B.
In order to avoid the occlusion of the effective region of the human body to be detected when the number of the second recognition objects 140 is too large, in an embodiment of the present invention, as shown in fig. 6, at least three second recognition objects 140 include two third recognition balls 141 arranged in the first direction a and one fourth recognition ball 142 arranged in the second direction B.
In a preferred embodiment of the present invention, as shown in fig. 7, the plurality of first subtags 1211 and the plurality of second subtags 1212 are resolved by a third two-dimensional coordinate system, specifically: the calibration target 100 includes a first recognition object 130 embedded on the first calibration target plate 1111 and a second recognition object 140 embedded on the second calibration target plate 1112, wherein the first recognition object 130 is disposed in the second direction B, the second recognition object 140 is disposed in the first direction a, and a third two-dimensional coordinate system is formed by the first recognition object 130 and the second recognition object 140, so that the plurality of first sub-mark objects 1211 can be confirmed one by one through the third two-dimensional coordinate system.
In order to avoid that the first recognition object 130 and/or the fourth recognition object 140 is/are blocked by the human body to be detected when the radiation emitted by the radiation source 200 scans along different angles, and thus an effective third two-dimensional coordinate system cannot be established, in an embodiment of the present invention, as shown in fig. 8, the calibration target 100 includes two first marker objects 130 arranged in the second direction B and three second recognition objects 140 arranged in the first direction a.
It should be noted that: the first recognition object 130 and the second recognition object 140 should be disposed at positions near the middle of the first calibration target plate 1111 and the second calibration target plate 1112, so as to prevent the first recognition object 130 and the second recognition object 140 from being not projected onto the imaging detector 300 when the calibration target 100 is biased or the radiation emitted from the radiation source 200 is biased, which may result in failure to effectively recognize the plurality of first sub-markers 1211 and the plurality of second sub-markers 1212, and the reliability of the calibration target 100 may be improved by disposing the first recognition object 130 and the second recognition object 140 at positions near the middle of the first calibration target plate 1111 and the second calibration target plate 1112.
In order to ensure that the calibration accuracy of the calibration target 100 meets the requirement, the distance between the first calibration target plate 1111 and the second calibration target plate 1112 is 50mm-100 mm.
Since the human body to be detected is divided into a front side and a back side, the application scenarios of the medical imaging system are also divided into two, the first application scenario is shown in fig. 1, and the radiation source 200 is disposed below the human body to be detected, that is: the radiation emitted from the radiation source 200 enters from the back of the human body to be detected and is emitted from the front of the human body to be detected to the imaging detector 300. A second application scenario is shown in fig. 9, where a radiation source 200 is placed above the body to be examined, namely: the radiation emitted from the radiation source 200 enters from the front side of the human body to be detected and is emitted from the back side of the human body to be detected to the imaging detector 300. The first calibration target plate 1111 and the second calibration target plate 1112 in the two application scenarios are different from each other in spacing.
Specifically, the method comprises the following steps: when the medical imaging system is in the application scenario as shown in fig. 2, the distance between the first calibration target plate 1111 and the second calibration target plate 1112 is 75mm-100 mm.
The reason why the above-mentioned pitch is set is: when the distance between the first calibration target plate 1111 and the second calibration target plate 1112 is less than 75mm or greater than 100mm, the calibration error of the calibration target 100 is greater than 1mm, and the calibration precision is not satisfied.
In a preferred embodiment, the first calibration target plate 1111 is spaced from the second calibration target plate 1112 by 88 mm.
With the above arrangement, the calibration accuracy of the calibration target 100 can be maximized, because the calibration accuracy of the calibration target 100 is highest when the distance between the first calibration target plate 1111 and the second calibration target plate 1112 is 88 mm.
When the medical imaging system is in the application scenario as shown in fig. 9, the distance between the first calibration target plate 1111 and the second calibration target plate 1112 is 50mm to 70 mm.
The reason why the above-mentioned pitch is set is: when the distance between the first calibration target plate 1111 and the second calibration target plate 1112 is smaller than 50mm or larger than 70mm, the calibration error of the calibration target 100 is larger than 1mm, and the calibration precision is not satisfied.
In a preferred embodiment, the first calibration target plate 1111 is spaced from the second calibration target plate 1112 by 56 mm.
With the above arrangement, the calibration accuracy of the calibration target 100 can be maximized, because the calibration accuracy of the calibration target 100 is highest when the distance between the first calibration target plate 1111 and the second calibration target plate 1112 is 56 mm.
In some embodiments of the present invention, the calibration accuracy of the calibration target 100 is: the calibration error is less than or equal to 1 mm.
Based on the calibration accuracy, the embodiment of the present invention further performs experimental verification on the adjustment amount in two application scenarios of the medical imaging system, and establishes an X-axis and a Y-axis respectively with respect to a plane of the imaging detector 300 close to the radiation source 200, and takes a direction from the imaging detector 300 to the radiation source 200 as a Z-axis, where the adjustment amount includes translation distances of the calibration target 100 along the X-axis, the Y-axis, and the Z-axis, and rotation angles along the X-axis, the Y-axis, and the Z-axis, respectively. On the premise of ensuring the calibration accuracy of the calibration target 100, the adjustment range of the adjustment amount is shown in table 1:
TABLE 1 adjustment Range of adjustment
The translation distances of calibration target 100 in table 1 along the X-axis, Y-axis, and Z-axis, respectively, are based on the initial position of calibration target 100. When the medical imaging system is in the first application scenario, the initial position of the calibration target 100 is a position where the distance between the calibration target 100 and the imaging detector 300 is 30mm, that is: the coordinates of the calibration target 100 are (0,0, 30). When the medical imaging system is the second application scenario, the initial position of the calibration target 100 is a position where the distance between the calibration target 100 and the imaging detector 300 is 430 mm.
In another aspect, the present invention further provides a medical imaging system, which includes a radiation source, an imaging detector, and a human body stage and a calibration target disposed between the radiation source and the imaging detector, wherein the calibration target is the calibration target 100 in any of the embodiments described above.
Wherein the medical imaging system may be any one of a C-arm imaging system, a CT imaging system, and the like.
The calibration target and the medical imaging system provided by the utility model are described in detail above, and the principle and the implementation mode of the utility model are explained in the text by applying specific examples, and the description of the above examples is only used for helping to understand the method and the core idea of the utility model; meanwhile, for those skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.
Claims (12)
1. A calibration target is characterized by comprising a calibration target substrate and a plurality of marker bodies embedded in the calibration target substrate;
the calibration target substrate comprises a first calibration target substrate and a second calibration target substrate, and the plurality of mark bodies comprise a plurality of first mark bodies embedded in the first calibration target substrate and a plurality of second mark bodies embedded in the second calibration target substrate;
the total number of the first marker bodies is greater than or equal to the first threshold number, so that the calibration precision is ensured.
2. The calibration target of claim 1, wherein the total number of the plurality of first markers is less than or equal to a second threshold number.
3. The calibration target according to claim 1, wherein the first calibration target substrate comprises a first calibration target plate, a second calibration target plate and at least one connecting plate, the first calibration target plate and the second calibration target plate are disposed opposite to each other, two sides of the at least one connecting plate are respectively connected to the first calibration target plate and the second calibration target plate, and the plurality of first mark bodies comprise a plurality of first sub-mark bodies embedded in the first calibration target plate and a plurality of second sub-mark bodies embedded in the second calibration target plate.
4. The calibration target according to claim 3, wherein the diameters of each of the plurality of first sub-label bodies are the same, and the diameters of each of the plurality of second sub-label bodies are the same;
the diameter of each first sub-label is different from the diameter of each second sub-label.
5. The calibration target according to claim 4, wherein the diameter of each first sub-label is 1.5mm-2.5mm, and the diameter of each second sub-label is 2.5mm-3.5 mm.
6. The calibration target of claim 3, wherein the first calibration target plate is parallel to the second calibration target plate.
7. The calibration target of claim 6, wherein the spacing between the first calibration target plate and the second calibration target plate is 50mm-100 mm.
8. The calibration target according to claim 3, wherein the total number of the first plurality of sub-markers is different from the total number of the second plurality of sub-markers.
9. The calibration target according to claim 3, wherein the plurality of first sub-markers are staggered with respect to the plurality of second sub-markers along the orthographic projection direction of the first calibration target plate.
10. The calibration target according to claim 4, further comprising at least one first recognition object embedded in the first calibration target plate and at least one second recognition object embedded in the second calibration target plate, wherein the diameter of the at least one first recognition object is the same as the diameter of each first sub-marker body, and the diameter of the at least one second recognition object is the same as the diameter of each second sub-marker body.
11. The calibration target according to claim 3, wherein the attenuation degrees of the first sub-markers in the plurality of first sub-markers are the same, the attenuation degrees of the second sub-markers in the plurality of second sub-markers are the same, the attenuation degrees of the first sub-markers are different from the attenuation degrees of the second sub-markers, and the attenuation degrees of the first sub-markers and the attenuation degrees of the second sub-markers are both greater than the attenuation degree of the calibration target substrate.
12. A medical imaging system, comprising a radiation source, an imaging detector, a human body stage arranged between the radiation source and the imaging detector, and a calibration target according to any one of claims 1 to 11; the area formed by rays emitted by the radioactive source is a scanning area, the first calibration target substrate is positioned in the scanning area, and the second calibration target substrate is positioned outside the scanning area.
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