Summary of the invention
Technical problem to be solved by this invention is; A kind of method, a kind of calculation procedure, a kind of data medium and a kind of computed tomographic scanner that starts said type are provided; Thereby can improve the picture quality of organizing faultage image that during helical scanning, generates, the picture quality of the faultage image of the tissue that the system axis of especially improving centrage or organizing axis when the patient lies low on the patient support plate, to be not parallel to computed tomographic scanner is extended.
The method of taking the X ray projection of patient's specified tissue through a kind of helical scanning that is used for carrying out at the tomoscanner that uses a computer by this technical problem of the present invention solves; Wherein, Having at least one x-ray source and at least one X-ray detector and isocentric x-ray system and patient conditioned when the projection of shooting X ray moves relative to each other along the direction of the isocentric system axis of computed tomographic scanner extend past; Wherein, Specified tissue has along its centrage that scans or organizes axis; But centrage or organize axis when the patient lies low on examining table, to be not parallel to the isocentric system axis of computed tomographic scanner extend past x-ray system; Wherein, x-ray system and patient's conditioned make up against each other and move or synthetic moving, make centrage or organize axis move through x-ray system etc. the center.
Therefore inventor's suggestion of the present invention, according to remain in faultage image or stereo data group, to be formed images, specify the centrage of the tissue of paying close attention to or organize the trend of axis that x-ray system and patient are regulated each other.Because centrage or organize axis when the patient lies low on examining table, to be not parallel to the system axis of computed tomographic scanner or for example be not parallel to the patient support plate surface of examining table; So it is not to carry out along the system axis direction merely that x-ray system and patient's the formula that relatively moves is regulated, but also has at least one component motion transverse to system axis linearly.Can realize by this way; Remain in faultage image, to be formed images, being organized in of specify paying close attention to always be positioned at least in part when taking the X ray projection x-ray system etc. center or x-ray system photographic plane etc. the center, can generate or rebuild thus and specify the constant faultage image of paying close attention to of liver mass.
In addition, scanning, especially helical scanning are interpreted as the X ray projection of taking patient tissue from different projecting directions, the especially X ray projection of two dimension, and wherein, x-ray system and patient relatively move constantly.
Organize generally can have many and organize axis, for example the main shaft of three mutually orthogonal orientations.The patient is directed or settle at this so relative x-ray system for helical scanning, makes helical scanning to carry out along the desirable tissue axis.
By a kind of flexible program of the present invention; The patient lies low on examining table; Wherein at least one parts of examining table or examining table when taking the X ray projection conditioned in height and/or transverse to system axis move, make centrage or organize axis move through x-ray system etc. the center.In the third-generation computer tomoscanner, generally not translation of frame, but fixed-site.And for example examinating couch or the patient support platform patient support plate of accepting the patient originally relatively the frame direction of carrying out altitude mixture control tailing edge system axis regulate point-blank.In this flexible program of the present invention; At least one parts of examining table or examining table additionally in height and/or transverse to system axis are regulated when taking the X ray projection like this, make centrage or organize axis move through x-ray system etc. the center.But also have the third-generation computer tomoscanner with " sliding frame ", wherein, frame is regulated when taking the X ray projection with respect to the examining table that has in height carried out regulating point-blank.Therefore in this form of implementation of the present invention, the patient support plate of examining table does not carry out the straight line adjustment movement along the system axis direction, but at least one parts of examining table or examining table only in height and/or transverse to system axis ground are regulated.Mixed form between two flexible programs is also contained among the present invention at this.
By another kind of flexible program of the present invention, x-ray system in height and/or transverse to patient ground moves adjusting when taking the X ray projection, make centrage or organize axis move through x-ray system etc. the center.In this form of implementation of the present invention; For example carry out rectilinear motion along system axis through regulating the patient support plate; And through x-ray system or to have the frame of x-ray system in height corresponding and/or transverse to moving adjusting in patient ground so that with centrage or organize axis move towards mate.Also can additionally in height and/or laterally regulate mobile for example patient support plate at this.In addition, adjustment movement can only be undertaken by the sample of x-ray system according to " sliding frame ", so that also carry out height and/or horizontal adjusting except the rectilinear motion of x-ray system or frame.In this case, the mixed form between the flexible program is also included among the present invention.
By a kind of form of implementation of the present invention, x-ray system additionally tilts or tumbles around at least one axis that extend perpendicular to system axis when taking the X ray projection.This tipping line is generally with respect to system axis horizontal-extending (extending in horizontal plane).Can produce through x-ray system or inclination or tumble with frame of x-ray system and to specify the tissue paid close attention to perpendicular to centrage or organize the faultage image or the cross sectional image of axis orientation.
By a kind of design of the present invention,, takes the tomoscanner that uses a computer at least one spacer (Topogramm) of patient before carrying out helical scanning, the centrage of labelling specified tissue or organize the trend of axis in this spacer.When taking at least one spacer, x-ray system and patient only relatively move point-blank.Take spacer mostly backward or from the side in the past.But also can take a width of cloth spacer respectively along both direction.If for example need the spinal column of scan patients; Then the patient for example is positioned on the patient support plate; And revolve from its vertical home position when turning 90 degrees at x-ray system; Just take the spacer of patient's spinal column from the side, wherein, only regulate the patient support plate along the relative x-ray system of system axis direction point-blank.In this case, can be in this spacer the centrage of spinal column or the spinal column longitudinal axis of depicting the two S shapes of spinal column be drawn as or be labeled as the axis of organizing that is used for spinal column.The centrage of spinal column is not parallel to can be charged to the system axis in the spacer equally and organize generally also relative system axis inclination of axis.
By another kind of design of the present invention, regulate according to centrage labelling, specified tissue at least one spacer or the combination moving type of organizing the trend of axis to carry out x-ray system and patient.At this, preferred automatically by centrage or organize the trend of axis labelling to calculate centrage or organize axis to move towards the deviation of relative system axis, and convert thereof into the control data of the altitude mixture control that for example is used for patient support plate and/or x-ray system.
A kind of flexible program regulation of the present invention; Said at least one mark centrage or organize in the spacer of axis trend relatively centrage or organize axis additionally to mark some positions or location point; At these positions or location point; X-ray system should or be tumbled with respect to patient's inclination; So that can be as far as possible perpendicular to centrage or organize axis ground to take the X ray projection of specifying the tissue of paying close attention to, and therefore can produce or rebuild perpendicular to centrage or organize the faultage image of axis orientation with simple mode.
Preferred adjust this inclination angle also for each position that marks regulation or stipulate or calculate the inclination angle or the angle of overturn automatically, make can be as far as possible perpendicular to centrage or organize axis ground to take the X ray projection of the tissue of appointment concern.
Technical problem to be solved by this invention also solves through a kind of calculation procedure that is used to implement one of preceding method, a kind of data medium and a kind of computed tomographic scanner of computing unit that comprises with this calculation procedure, and this computing unit has aforesaid calculation procedure.
The specific embodiment
In the accompanying drawings, identical or function components identical is equipped with identical Reference numeral fully.Just schematic shown in these accompanying drawings, not forcibly not in proportion.Regarding to computed tomographic scanner 1 down only is described under the general situation to understanding degree required for the present invention not limiting.
Computed tomographic scanner 1 shown in Fig. 1 comprises frame 2, and this frame has standing part 3 and centers on the rotatable part 4 of system axis S.Rotatable part 4 has the x-ray system that comprises x-ray source 6 and X-ray detector 7 in an embodiment of the present invention, and this x-ray source 6 is arranged on the rotatable part 4 with X-ray detector 7 mutually opposed to each other.In addition, frame 2 or rotatable part 4 such as also have at center IZ, and these centers IZ is positioned at that system axis S goes up and the expression x-ray system rotates point or the mid point that is centered on.When computed tomographic scanner 1 operation, X-ray beam 8 direction towards X-ray detector 7 from x-ray source 6 penetrates, and penetrates Measuring Object and is detected by X-ray detector 7 with the form of measurement data or measuring-signal.
Frame 2 also comprises the standing part 3 that is furnished with frame 2 on it and the pedestal 5 of rotatable portion 4.The standing part 3 of frame 2 and rotatable portion 4 direction inclination or the upset of pedestal 5 around tipping line K along four-headed arrow a relatively jointly.The tipping line K of frame 2 arranges perpendicular to system axis S ground and essentially horizontally extends.For the standing part that makes frame 23 and rotatable portion 4 relatively pedestal 5 be provided with a supporting that in Fig. 1, schematically shows and driver element 20 at least one side of pedestal 5 around tipping line K inclination or tumble.
Computed tomographic scanner 1 also has the examining table 9 of the patient P that is used to settle examine.Examining table 9 comprises a pedestal 10, which is provided with one and is designed for the patient support plate 11 of really accepting patient P.In this embodiment of the present invention, patient support plate 11 is arranged on the pedestal 10 like this, make this patient support plate 11 relatively pedestal 10 regulate along the direction of system axis S.Therefore, patient support plate 11 can be used for taking in the door opening two-dimensional x-ray projection, frame 2 or passage 12 of patient P in for example helical scanning with common importing of patient P.In addition, in this embodiment of the present invention, pedestal 10 is scalable in height.
Rebuild faultage image, 3-D view or three-dimensional data group by tomography computer 13 computings that schematically show, computed tomographic scanner 1 through the two-dimensional x-ray projection of x-ray system shooting or according to the measurement data or the measuring-signal of two-dimensional x-ray projection.
Computed tomographic scanner 1 also has a computing unit 14 that is connected with tomography computer 13, can carry out and carry out the calculation procedure that is used to operate with Control Computer tomoscanner 1 through this computing unit 14.Computing unit 14 needn't be designed to independent computing unit 14 at this, but can also be integrated in the computed tomographic scanner 1 as said tomography computer 13 in addition.
In this embodiment of the present invention; A calculation procedure 15 is packed in the computing unit 14; This calculation procedure 15 implement a kind of by of the present invention be used for improving organize the faultage image method for quality, the axis of this tissue or organize axis when the patient lies low on the patient support plate, to be not parallel to the system axis of patient support plate surface or x-ray system.Calculation procedure 15 is in a kind of special operational mode that is used for computed tomographic scanner 1 of this expression and can be from data medium movably; For example CD16 or memory stick or via network 18 from server 17 is packed computing unit 14 into, this network 18 can be that public network also can be the internal network of clinic or hospital.
In this embodiment of the present invention, need the spinal column of inspection patient P, that is, should generate the faultage image that continues mutually before and after the spinal column of patient P along the direction of system axis S, these faultage images should have high and constant as far as possible quality.
For this reason, in the method, obtain the spacer that a width of cloth patient P has the body region of spinal column at first in a manner known way.After patient P lay low on patient support plate 11, this patient support plate 11 in height was adjusted to through pedestal 10, made the system axis S spinal column of extend past patient P at least approx of x-ray system.The surface of patient support plate 11 and the system axis S of x-ray system extend at this in parallel to each other.As shown in Figure 1, x-ray system is revolved from its vertical home position turn 90 degrees lateral position.In this embodiment of the present invention, in the said lateral location of x-ray system, take spacer, wherein, linearly regulate the patient support plate 11 that has patient P along the direction of system axis.
The spacer 21 of schematically illustrated shooting in Fig. 2 is as it illustrates on the display device 22 of computing unit 14.At this, but the current trend of in insight illustrates the spacer 21 of spinal column W, drawing system axis S.In addition, in spacer 21 record or the centrage M of labelling spinal column W and spinal column W organize longitudinal axis G, wherein, the longitudinal axis G that organizes of spinal column W has write down two S shapes of spinal column W.The axis M of spinal column W and organize the labelling of longitudinal axis G or the record can be, for example computer mouse or automatically for example realize by algorithm for pattern recognition manually by attaching troops to a unit in the entering apparatus of computing unit 14.
As clearly visible from Fig. 2, the centrage M of spinal column W is not parallel to system axis S and extends, and organizes also relative system axis S inclination of longitudinal axis G.If as when carrying out helical scanning, only regulate patient support plate 11 along the direction that shows the system axis S that waits IZ position, center point-blank at large so far, centrage M and organize the longitudinal axis G scarcely can be on IZ such as the center of grade then.
From this reason; According to the known trend of trend labelling in spacer 21, centrage M and system axis S, convert in order to regulate the control signal of patient support plate 11 and pedestal 10 along the distance between line M of system axis S computer center and the system axis S and by computing unit 14.In this embodiment of the present invention, system axis S only has along the deviation of x axis direction along the direction extension and the centrage M relative system axis S of the z axis of the rectangular coordinate system of drawing among Fig. 1.Therefore, the control signal of calculating is the signal relevant with the altitude mixture control of pedestal 10.
According to trend labelling, that organize longitudinal axis G in spacer 21 and the known trend of system axis S, convert in order to regulate the control signal of patient support plate 11 or pedestal 10 in an identical manner along the distance between longitudinal axis G of system axis S computation organization and the system axis S and by computing unit 14.In this embodiment of the present invention, also only have along the deviation of x axis direction at the said situation longitudinal axis G of undertissue relative system axis S.Therefore, equally also be the signal relevant for the control signal of organizing longitudinal axis G to calculate with the altitude mixture control of pedestal 10.
In addition; For the centrage M in the spacer 21; Can be along centrage M regulation some positions or location point like this, should tilt especially like this or overturn around tipping line K in these location point place frames 2, make and when helical scanning, pass through x-ray system perpendicular to the projection of centrage M ground shooting X ray.The user can be one by one through the manual setting inclination angle or through confirm corresponding inclination angle labelling or mark these important position or location points in spacer 21 automatically based on centrage M and system axis S.Generate the corresponding skewed control signal that is used for frame 2 inclinations by these given information through computing unit 14.But also can represent or select whole piece centrage M in this case, thereby when helical scanning, make frame 2 mate continuously or tilt according to the trend of centrage M and system axis S practically.For this reason, move towards to produce in order to tumble continuously around tipping line K or the corresponding skewed control signal of banking motion for centrage M whole through computing unit 14.
In an identical manner, can make perpendicular to organizing longitudinal axis G to take the X ray projection according to organizing longitudinal axis G and system axis S to confirm the inclination angle like this for organizing longitudinal axis G.Can generate corresponding skewed control signal through computing unit 14 by spacer.
Be enforcement helical scanning, the user can select still to organize longitudinal axis G scanning in the edge along centrage M scanning, wherein, all has the control signal of relevant pedestal 10 altitude mixture control and the control signal of relevant frame 2 or x-ray system inclination for these two kinds of flexible programs.
If the user selects to carry out helical scanning along centrage M, then under the situation of the embodiment of the invention, when waiting center IZ or system axis S to rotate, regulate patient support plate 11 continuously along the direction of system axis S or z axle at x-ray system.This adjustment movement and pedestal 10 according to before the altitude mixture control stack of the control signal calculated, realize through this altitude mixture control, center IZ such as move through at the centrage M of spinal column when the direction of system axis S or z axis is regulated patient support plate 11.According to the skewed control signal of calculating before, frame 2 or x-ray system tilt around tipping line K accordingly simultaneously, because the wave-like of centrage M, this corresponding inclination is that a kind of continuous tilt along four-headed arrow a direction moves.
As alternative, the user can select along organizing longitudinal axis G to carry out helical scanning.In this case, also regulate patient support plate 11 continuously at x-ray system when waiting center IZ or system axis S to rotate along the direction of system axis S or z axis.This adjustment movement and pedestal 10 according to before the altitude mixture control stack of the control signal calculated, realize again through this altitude mixture control, at the center IZ such as organize that longitudinal axis G moves through of patient support plate 11 spinal column when system axis S or z axis direction are regulated.For along organizing the helical scanning of longitudinal axis G, frame only tilts once and in scan period to remain on this position by the control signal of calculating.
Under above-mentioned two kinds of situation of helical scanning, can rebuild the high-quality faultage image of patient P spinal columns by tomography computer 13 because when taking the X ray projection axis M or organize longitudinal axis G move through x-ray system etc. center IZ.
For controlling said method, the user interface of a pattern for example is provided preferably on computing unit 14.Button through pattern for example can also make computing unit 14 reference system axis S according to centrage M or organize longitudinal axis G to calculate in order to regulating the control signal of pedestal 10 height in the case, and according to centrage M or organize longitudinal axis G to calculate skewed control signal.In addition, can carry out the adjusting and the final startup helical scanning of other optional sweep parameter by known mode itself.
Different with the above embodiment of the present invention, can only use the centrage of spinal column or only use the longitudinal axis of organizing of describing spinal column for helical scanning, therefore also be merely the flexible program of selecting respectively and produce control signal corresponding.
Except lateral spacer; At least can also produce preferred along in the past another width of cloth spacer of backward directions so as for example can to carry out because the centrage of spinal column or organize the corresponding trend of longitudinal axis and possibly need, move along x-ray system and patient's y direction lateral adjustments respect to one another.Centrage or organize longitudinal axis to have corresponding y component that is to say if then can also carry out along the lateral adjustment of y axis direction except the adjusting of height.If cause centrage or organize longitudinal axis to move through isocentric adjustment movement to comprise x component and y component, then be commonly referred to as the lateral adjustments of relative system axis S.
The application of said method is not confined in the helical scanning of spinal column.And also can be according to other tissue of this method scanning, for example Thigh bone.Needn't always carry out the inclination of frame or x-ray system at this.This frame also can keep it in the vertical setting shown in Fig. 1 when helical scanning.
Also have this probability, that is, frame or x-ray system also can tilt around the axis that another is vertically extending, erect perpendicular to system axis and tipping line, as long as centrage has corresponding trend.
In this embodiment of the present invention, implement adjustment movement along each axis direction of rectangular coordinate system by examinating couch.But adjustment movement also can partly realize that by frame this frame for this reason must corresponding adjusting fully or only.