CN206044647U

CN206044647U - A kind of geometric correction die body of pin hole SPECT systems

Info

Publication number: CN206044647U
Application number: CN201620669705.7U
Authority: CN
Inventors: 任秋实; 李素莹; 杨昆; 谢肇恒
Original assignee: Peking University
Current assignee: Peking University
Priority date: 2016-06-29
Filing date: 2016-06-29
Publication date: 2017-03-29
Anticipated expiration: 2026-06-29

Abstract

The utility model discloses a kind of geometric correction die body of pin hole SPECT systems.Correction model body of the present utility model originates in the surface of matrix using the cavity that multiple straightway shapes are arranged in matrix, one end of cavity, and the other end is terminated in matrix；Length of the diameter of the cross section of cavity much smaller than cavity；Multiple cavitys in the same plane and each other no coincidence point, but at least three intersection points of extended line of straightway that each cavity is located；Radiosiotope medicine fills cavity, forms line source, and in cavity, the intersection point of the extended line of the straightway that concentration highest position is located is used as virtual point source；Virtual point source is obtained by randon conversion, the position of correction Point Source can be caused more accurate, so as to the calculating of elliptical orbit is also more accurate, so as to eliminate cumulative error, improve the degree of accuracy of correction；The features such as this utility model possesses strong simple to operate, controllability, cavity high precision.

Description

A kind of geometric correction die body of pin hole SPECT systems

Technical field

This utility model belongs to medical imaging technology, and in particular to a kind of geometric correction die body of pin hole SPECT systems.

Background technology

Single photon emission computerized tomography technology (Single-Photon Emission Computed Tomography, SPECT) using the missing technology of radionuclide, by the radiosiotope medicine for detecting biological intake in vivo The ray that thing is launched, carries out data reconstruction by algorithm for reconstructing, obtains distribution and the metabolic information of medicine and targeted molecular.It is empty Between resolution and sensitivity be the important parameter for weighing SPECT detector performances.Wherein, spatial resolution can be subject to detector brilliant The restriction of volumetric pixel size, and be difficult to obtain higher spatial resolution.Using pinhole collimator, based on pin hole zoom into as By adjusting object distance and image distance, principle, then can realize that flexible amplification is arranged so that the raising of spatial resolution is broken away from The restriction of transistor pixel size.The U-SPECT-II toy SPECT prototypes that Dutch Utrecht universities develop use spininess Hole hole collimator, spatial resolution have reached 0.3mm.The toy SPECT that research and development are adopted by Mediso companies of the U.S. is accurate using pin hole Straight device, it is already possible to reach the spatial resolution of submillimeter level.The SPECT detectors of integrated pinhole collimator, also in human body brain Portion, cardiac imaging have obtained certain application, while higher spatial resolution is provided, also can guarantee that counting rate and sensitivity are special Property.As can be seen here, pin hole SPECT detectors are most important to improving the spatial resolution that SPECT systems are imaged.

In using pin hole SPECT systems, need to carry out geometric correction to which.Geometric correction is that five parameters are carried out really It is fixed, for ensureing to reduce artifact during SPECT image reconstructions.

Pin hole SPECT systems as shown in figure 1, correction model body 1 is placed on object stage 2, by pin hole 3 in uv detector faces It is upper to form projection 1 '.Concrete parameters calibration is as shown in the table：

The geometric parameter for correcting is needed in the SPECT systems of single needle hole

Relatively conventional geometric correction method is iterative method and parsing fitting process.During geometric correction, will Projection acquisition is carried out based on point source, and then carries out geometric correction algorithm.Generally by making less entity point, (diameter control exists Within 0.5mm), approximately it is used to correct as point source.However, in practical operation engineering, due to radiosiotope medicine it is many For liquid condition, make that point source room body is more difficult, the point Source size made also is difficult to hold.And entity point source has necessarily Volume, compare preferable point source and there is error, also can bring in trimming process, affect correction accuracy；Entity liquid point source is being grown It is wayward in time experimentation, it is readily volatilized, bring various inconvenience in experimentation.

Utility model content

For above problems of the prior art, the utility model proposes a kind of geometry of pin hole SPECT systems Correction model body, the features such as possess strong simple to operate, controllability, cavity high precision.

The geometric correction die body of pin hole SPECT systems of the present utility model includes：Matrix and multiple cavitys；Set in matrix Multiple cavitys are put, one end of cavity originates in the surface of matrix, and the other end is terminated in matrix；Each cavity is straightway shape Shape, the diameter of the cross section of cavity are much smaller than the length of cavity；The straightway that multiple cavitys are located is located in approximately the same plane, and And no intersection point each other, but at least there are three intersection points in the extended line of straightway that each cavity is located；Radiosiotope medicine Thing fills cavity, forms line source, and the intersection point of the extended line of the straightway that cavity is located is used as virtual point source；Correction model body is placed on On object stage, and the intersection point of the extended line of straightway that cavity is located at least has three not in the rotary shaft of object stage, Pinhole collimator is set between correction model body and SPECT detectors, SPECT geometric correction systems are formed.

The diameter of the cross section of cavity is in below 0.5mm；The length of cavity is in more than 20mm.

The material of the matrix of correction model body adopts acrylic or vinyon.

Advantage of the present utility model：

This utility model using the cavity that multiple straightway shapes are arranged in matrix, using the intersection point of cavity extended line as Virtual point source；Virtual point source is obtained by randon conversion, the position of correction Point Source can be caused more accurate, so as to ellipse The calculating of track also more accurately, so as to eliminate cumulative error, improves the degree of accuracy of correction；This utility model possesses operation letter Single, controllability is strong, cavity high precision the features such as.

Description of the drawings

Schematic diagrams of the Fig. 1 for SPECT geometric correction systems, wherein, it is (a) structure chart, is (b) schematic diagram, (c) visits for uv The schematic diagram of the face internal rotation angle surveyed in device face；

Fig. 2 is the profile of one embodiment of SPECT geometric corrections die body of the present utility model；

Fig. 3 is a plurality of straight line and friendship obtained according to one embodiment of SPECT geometric correction methods of the present utility model The schematic diagram of point；

Fig. 4 is i-th virtual point source obtained according to one embodiment of SPECT geometric correction methods of the present utility model The schematic diagram of the elliptical orbit formed in uv detector faces.

Specific embodiment

Below in conjunction with the accompanying drawings, by specific embodiment, this utility model is expanded on further.

As shown in figure 1, the SPECT geometric correction die bodys of the present embodiment include：Matrix 11 and first to fourth cavity 12～ 15；The straightway that 11 12～15,4 cavitys of cavity for arranging 4 straightway shapes are located in the matrix is located at approximately the same plane, The cross section of each cavity is 0.5mm, and length is that, more than 20mm, one end of cavity originates in the surface of matrix, other end end Terminate in matrix；First cavity 12 is vertical direction, and the second to the 4th cavity 13～15 is parallel to each other, and extended line is respectively with first Cavity 12 intersects, and forms 3 intersection points, as 3 virtual point sources.

Pin hole SPECT geometric correction methods of the present utility model, comprise the following steps：

1) radiosiotope medicine is filled in each cavity of correction model body, form 4 line sources；

2) correction model body is placed on object stage, pinhole collimator is set between correction model body and SPECT detectors；

3) each cavity is projected on SPECT detectors, extracts radiosiotope drug level highest in cavity Position obtains the straightway in uv detector faces；

4) line source formed by each cavity is projected as straight line section in uv detector faces, will be per straight line Section is converted by Laden randon, and correspondence obtains a point of polar coordinate space；

5) each point in polar coordinate space is carried out into anti-randon conversion, respectively obtains 4 in uv detector faces Straight line, then finds 3 intersection points of a plurality of straight line intersection, and this 3 intersection points is not in the rotary shaft of object stage, such as Fig. 3 It is shown, form projection of the virtual point source in uv detector faces；

6) inner in stage coordinate system (x, y, z), object stage drives correction model body to rotate to certain angle, and repeat step is 3) ～5), until object stage is rotated by 360 °, the projection in uv detector faces of the virtual point source under each anglec of rotation is obtained, Then in uv detector faces, projection of each virtual point source under each anglec of rotation in uv detector faces is carried out into line, Form the elliptical orbit of 3 virtual point sources；

7) elliptical orbit formed with virtual point source carries out geometric correction to pin hole SPECT systems.

It is finally noted that, the purpose for publicizing and implementing example is that help further understands this utility model, but this The technical staff in field is appreciated that：It is in without departing from this utility model and appended spirit and scope by the claims, various Substitutions and modifications are all possible.Therefore, this utility model should not be limited to embodiment disclosure of that, and this utility model will The scope of protection is asked to be defined by the scope that claims are defined.

Claims

1. a kind of geometric correction die body of pin hole SPECT systems, it is characterised in that the correction model body includes：Matrix and multiple Cavity；Multiple cavitys are set in matrix, and one end of cavity originates in the surface of matrix, and the other end is terminated in matrix；It is each Individual cavity is straightway shape, the length of the diameter of the cross section of cavity much smaller than cavity；The straight line section that multiple cavitys are located In approximately the same plane, and no intersection point each other, but at least there are three friendships in the extended line of the straightway at each cavity place Point；Radiosiotope medicine fills cavity, forms line source, and the intersection point of the extended line of the straightway that cavity is located is used as virtual point Source；The correction model body is placed on object stage, and the intersection point of the extended line of the straightway at cavity place at least has three Not in the rotary shaft of object stage, pinhole collimator is set between correction model body and SPECT detectors, SPECT geometry is formed Correction system.

2. the geometric correction die body of pin hole SPECT systems as claimed in claim 1, it is characterised in that the cavity it is transversal The diameter in face is in below 0.5mm.

3. the geometric correction die body of pin hole SPECT systems as claimed in claim 1, it is characterised in that the length of the cavity In more than 20mm.

4. the geometric correction die body of pin hole SPECT systems as claimed in claim 1, it is characterised in that the correction model body The material of matrix adopts acrylic or vinyon.