CN106693215B - The localization method of crosshair in radiotherapy equipment - Google Patents

The localization method of crosshair in radiotherapy equipment Download PDF

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CN106693215B
CN106693215B CN201611263241.0A CN201611263241A CN106693215B CN 106693215 B CN106693215 B CN 106693215B CN 201611263241 A CN201611263241 A CN 201611263241A CN 106693215 B CN106693215 B CN 106693215B
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crosshair
new
frame
center
central projection
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CN106693215A (en
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杨宏成
朱建伟
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Shanghai United Imaging Healthcare Co Ltd
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N5/1001—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy using radiation sources introduced into or applied onto the body; brachytherapy
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N5/1048—Monitoring, verifying, controlling systems and methods
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N5/1077—Beam delivery systems
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N5/1048—Monitoring, verifying, controlling systems and methods
    • A61N5/1049—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam
    • A61N2005/1054—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam using a portal imaging system
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N5/1048—Monitoring, verifying, controlling systems and methods
    • A61N5/1049—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam
    • A61N2005/1056—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam by projecting a visible image of the treatment field
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N2005/1092—Details

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  • Biomedical Technology (AREA)
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Abstract

The embodiment of the present invention provides a kind of localization method of crosshair in radiotherapy equipment.The localization method includes: in the state that the rotary frame of radiotherapy equipment is in the first frame angle, around the longitudinal axis rotation therapy head for the treatment of head, so that treatment head is at least three predetermined positions, wherein be equipped with crosshair in the ray path in treatment head；Crosshair is acquired through the corresponding projected image of radiation exposure by image acquisition element in each predetermined position；According to any of projection of the center of crosshair in each projected image and multiple projected images, offset of the physical location of the crosshair in the first frame angle relative to its ideal position is determined.Above scheme, by ray projection come the position of positioning cross cross hair, precision is higher, and it is more convenient to operate.

Description

The localization method of crosshair in radiotherapy equipment
Technical field
The present invention relates to a kind of positioning of crosshair in the positioning field of radiotherapy more particularly to radiotherapy equipment Method.
Background technique
Collimator assembly is the usual means in existing radiological installation, needs to make in the typical such as therapeutic equipments based on X-ray The launched field of X-ray is formed with collimator assembly.
It is as shown in Figure 1 a kind of basic structure of radiotherapy equipment in the prior art, mainly includes therapeutic bed 10, fixed Rack 20 and rotary frame 30.Rotary frame 30 is connected with fixed frame 20, as shown in Figure 1, can be around the water of fixed frame 20 Flat axis rotates integrally.Treatment head 31 in rotary frame 30 can independently be rotated around the longitudinal axis of fixed frame 20.Therapeutic bed 10 It can also move in parallel and rotate.Above-mentioned relative motion is to be able to the sufferer tissue position for making ray accurately inject patient It sets.
In order to be positioned, radiotherapy equipment positions three orthogonal axis with laser lamp, as shown in Figure 1, three The joint of a axis is known as waiting centers.In order to carry out precise positioning in radiotherapy, no matter such as each equipment is theoretically required The beam axis of what relative motion, the X-ray emitted in treatment head 31 will be just past equal centers.X-ray is usually one A lesser conical beam of apex angle, the center vertical pivot of the conical beam are exactly beam axis.
It is illustrated in figure 2 the schematic diagram of internal structure for the treatment of head in the prior art.The electron accelerator and collimation group of X-ray Part is arranged in treatment head, can be rotated with treatment head around longitudinal vertical pivot.The structure of collimator assembly is as shown in Fig. 2, electron beam passes through The X-ray issued after x-ray target 40 is crossed, example of primary collimator 50, expansion device and ionisation chamber are first passed around, then by secondary quasi- Straight device 60.The lower section of secondary collimator 60 is equipped with the two pairs of tungsten blocks 70 that is mutually perpendicular to and can move in parallel, also known as tungsten door, wherein In a first direction, another pair tungsten block is located in the second direction vertical with first direction for a pair of of tungsten block positioning, their common restrictions Scheduled rectangular aperture out.X-ray is launched by the rectangular aperture.
Theoretically, when the tungsten door of first direction and second direction is symmetrically arranged respectively about its launched field, for example, When the maximum launched field of 40cm × 40cm is in the rectangular aperture that they are limited, the beam axis of X-ray is consistent with the center in the rectangular aperture. Since X-ray is black light, so crosshair 80, which would generally be arranged, in the lower section of secondary collimator 60 carrys out the positioning of halved tie axis. It is desirable that the tungsten door edge of a cross hair of crosshair 80 and the tungsten door sides aligned parallel of side and another cross hair and the other side In parallel, and the center of crosshair 80 is consistent with beam beam axis.However, due to such as equipment precision, installation, for a long time making With etc. all various aspects reason so that the beam axle offset of the center of actually crosshair and X-ray is opened, and crosshair Also there can be angle between each cross hair and the edge of corresponding tungsten door, above-mentioned deviation is needed periodically or is non-regularly determined.
In the prior art in order to determine that scheme used by whether the central point of crosshair is consistent with beam axis for example can be with It is: rotary frame is turned into initial position, is i.e. the treatment head vertical state that is located at top, at this time the laser to be located on vertical pivot Light irradiation crosshair carries out optical projection in detection plane.Detection plane is located at isocentric generally relative to treatment head The other side, and be known with the distance between equal centers relationship.By in the optical projection and grade of artificial observation crosshair Whether imaging of the heart in detection plane is overlapped to determine offset.
However, the prior art is in such a way that human eye observation projects and is overlapped, there are many defects.The first, eye-observation is with master The property seen, and it is inaccurate；The second, projected image edge blurry of the visible light in detection plate；Third corrects ten since needs are frequent Word cross hair, it is clear that existing bearing calibration is inconvenient, and precision is difficult to ensure.
Summary of the invention
The embodiment of the present invention provides a kind of localization method of crosshair in radiotherapy equipment, to realize to ray equipment The convenient positioning of middle crosshair.
The embodiment of the invention provides a kind of localization methods of crosshair in radiotherapy equipment, comprising: puts described The rotary frame for penetrating therapeutic equipment is in the state of the first frame angle, and the longitudinal axis around the treatment head rotates the treatment Head, so that the treatment head is at least three predetermined positions, wherein be equipped with ten in the ray path in the treatment head Word cross hair；The crosshair is acquired through the corresponding perspective view of radiation exposure by image acquisition element in each predetermined position Picture；According to any of projection of the center of the crosshair in each projected image and multiple projected images, Determine offset of the physical location of the crosshair described in first frame angle relative to its ideal position.
Specifically, the projection and multiple projected images according to the center of the crosshair in each projected image Any of, determine the physical location of the crosshair described in first frame angle relative to the inclined of its ideal position It moves, comprising: according to central projection of the center of the crosshair in each projected image, obtain the crosshair The projected position at the center of ideal position, and then determine the physical location of the crosshair described in first frame angle Offset between center and the center of its ideal position.More specifically, the center according to the crosshair is each described Any of projection and multiple projected images in projected image, obtain the center of the ideal position of the crosshair Projected position, comprising: circular fit is carried out to the central projection of the center of the crosshair in each projected image, it will Projected position of the circular center of fitting as the center of the ideal position of the crosshair.
Specifically, the projection and multiple projected images according to the center of the crosshair in each projected image Any of, determine the physical location of the crosshair described in first frame angle relative to the inclined of its ideal position It moves, comprising: according to any of multiple projected images, determine the reality of the crosshair described in first frame angle Position and deflection of its ideal position in angle.
Specifically, the central projection and multiple projections according to the center of the crosshair in each projected image Any of image determines the physical location of the crosshair described in first frame angle relative to its ideal position Offset include at least determine following offset parameter: the central projection position (u of the ideal position of the crosshair1', v1′)、 The treatment head is in the projection of first direction cross hair when 0 degree in multiple predetermined positions in the crosshair and with described Deflection angle in the vertical second direction of first direction between the projection at the edge of moveable tungsten doorThe crosshair Physical location central projection position (u1, v1) with the central projection position (u of its ideal position1', v1') between vector (ushift, vshift)；Or the circle being fitted by the multiple predetermined position radius R and the treatment head be in 0 degree when institute State the central projection position (u of the physical location of crosshair1, v1) with the central projection position (u of its ideal position1', v1') Vectorial angle β.More specifically, further includes: when radiotherapy equipment rotary frame be in different from the first frame angle other When angle and the treatment head are in 0 degree, by the first frame angle and when treatment head is in 0 degree crosshair Physical location central projection position (u1, v1) with the central projection position (u of its ideal position1', v1') between vector (ushift, vshift) and in other frame angles the physical location of the crosshair central projection position (unew, vnew), determine the central projection position (u ' of the ideal position of the crosshairnew,v′new).Further, work as radiotherapy The rotary frame of equipment be in different from the first frame angle other angles and the treatment head be in 0 degree when, by the One frame angle and the treatment head are in the central projection position (u of the physical location of crosshair at 0 degree1, v1) and its Central projection position (the u of ideal position1', v1') between vector (ushift, vshift) and in other frame angle when institutes State the central projection position (u of the physical location of crosshairnew,vnew), determine the center of the ideal position of the crosshair Projected position (u 'new,v′new) it include: to be different from the first rack angle when the rotary frame of the radiotherapy equipment is in When the other angles of degree and the treatment head are in 0 degree, the central projection position (u ' of the ideal position of the crosshairnew, v′new) it is to be determined by following formula:
u′new=unew-ushift
v′new=vnew-vshift。
Selectively, in one embodiment further include: when the rotary frame of radiotherapy equipment is in different from described Other angles of first frame angle and when the treatment head is in α degree angle, by first frame angle and described Treatment head is in the central projection position (u of the physical location of crosshair at 0 degree1, v1) thrown with the center of its ideal position Shadow position (u1', v1') between vector (ushift, vshift) and in other frame angles the crosshair reality Central projection position (the u of positionnew,vnew), determine the central projection position (u ' of the ideal position of the crosshairnew, v′new) it include: when the rotary frame of radiotherapy equipment is in the other angles for being different from the first frame angle and treatment head is α When spending angle, the central projection position (u ' of the ideal position of the crosshairnew,v′new) it is to be determined by following formula :
Or determined by following formula:
u′new=unew-Rcos(α-β)
v′new=vnew-Rsin(α-β)。
The technical solution of the embodiment of the present invention is carried out using projection of the beam irradiation crosshair in detection plane Foundation is corrected, compared to the projection imaging of visible light source, image is more accurate, and resolution is higher；Also, using rotation collimation Device carries out the mode of multiple projected centre point circular fits, and the relative positional relationship that collimator and crosshair is utilized is come really Determine offset, is not necessarily to artificial observation, improves the accuracy of identification.
Detailed description of the invention
Fig. 1 is a kind of basic structure schematic diagram of radiotherapy bed apparatus in the prior art；
Fig. 2 is the schematic diagram of internal structure for the treatment of head in the prior art；
The process of the localization method of crosshair in a kind of radiotherapy equipment that Fig. 3 provides for an embodiment of the present invention Figure；
Fig. 4 is the position view of an embodiment of the present invention projected image.
Specific embodiment
The present invention is described in further detail with reference to the accompanying drawings and examples.It is understood that this place is retouched The specific embodiment stated is used only for explaining the present invention rather than limiting the invention.It also should be noted that in order to just Only the parts related to the present invention are shown in description, attached drawing rather than entire infrastructure.
The process of the localization method of crosshair in a kind of radiotherapy equipment that Fig. 3 provides for an embodiment of the present invention Figure, the present embodiment are applicable to position the crosshair in radiotherapy equipment, to obtain the crosshair installed The drift condition that physical location occurs relative to the ideal position of crosshair.This method can be realized by program, alternatively, the party Method can also be partially by manual operation, and cooperation is realized with controlling program.
Specifically, method 100 provided by the present embodiment includes:
S110, in the state that the rotary frame of the radiotherapy equipment is in the first frame angle, around the treatment The longitudinal axis of head rotates the treatment head, so that the treatment head is at least three predetermined positions, wherein penetrating in treatment head Crosshair is installed on thread path；
S120, crosshair is acquired through the corresponding projection of radiation exposure by image acquisition element in each predetermined position Image；
S130, central projection and multiple perspective views according to the center of the crosshair in each projected image Any of as, determine the physical location of the crosshair described in first frame angle relative to its ideal position Offset.
More specifically, the exemplary structure for the radiotherapy equipment that the present embodiment is applicable in can refer to Fig. 1 and Fig. 2 is managed Solution.It, can be before a period of time, for example, one week perhaps before one month or is also likely to be before step S110-S130 And then, for example, on the same day, executing the installation steps of crosshair, i.e., in the ray path of radiotherapy equipment, by cross Cross hair is mounted in treatment head.Image acquisition element is located at the isocentric other side relative to treatment head, and between equal centers Distance relation be known.As a kind of example, which can be electronic portal image device (EPID).Such as It is well known, image acquisition element can receive from radiographic source and by crosshair ray thus formed with crosshair pair The projected image for the crosswise answered.
For step S110 and S120, the treatment head in radiotherapy equipment is can be around the longitudinal central for the treatment of head itself Rotated in order to allow entire collimator assembly to be positioned to specific angle, the crosshair being installed in treatment head Thus as treatment head rotates and may be at specific angle.Normally, 0 degree for the treatment of head can be predefined, this is It is well known to those skilled in the art.Predetermined position can be not limited to 3, can also be arranged for location requirement more.It is exemplary Ground, treatment head position when treatment head is 0 degree can be used as the first predetermined position, and treatment head is with respect to the first predetermined position by the inverse time Needle has rotated 30 degree as the second predetermined position, continues to rotate counterclockwise 30 degree for the treatment of head position as third predetermined position. It is appreciated that not required as the first predetermined position when to select treatment head be 0 degree；Although between the angle in above-mentioned predetermined position 30 degree are divided into, however the angle interval in predetermined position can be arbitrary, such as can be 20 degree, 40 degree or 50 degree, and angle Degree interval is also possible to different between any two, for example, 20 degree of the second predetermined position and the first predetermined position interval, third makes a reservation for 30 degree of position and the second predetermined position interval.In this way, how many predetermined position, it will be able to obtain the perspective view of how many crosshair Picture.
For step S130, if the physical location of the crosshair of installation is to have relative to the ideal position of crosshair Offset, then, the situation of the offset is to be deviateed by the physical location at the center of (1) crosshair relative to its ideal position Open (angular deflection for not considering cross hair), and/or (2) crosshair physical location relative to its ideal position in angle On have deflection the position of cross hair center (do not consider deviate), caused by.
For the first aforementioned offset situation, can be determined according to multiple projected images of collected crosshair； For second of offset situation, can be determined according to any of multiple projected images.
Situation is deviated for the first, specifically, can exist according to the center of the crosshair in the first frame angle Central projection in each projected image obtains the projected position at the center of the ideal position of the crosshair, and then really It is scheduled on inclined between the center of the physical location of the crosshair and the center of its ideal position when first frame angle It moves.More specifically, carrying out circular fit to the central projection of the center of the crosshair in each projected image, will intend Projected position of the circular center closed as the center of the ideal position of the crosshair.
Specifically, when the physical location of the crosshair of installation and its ideal position, which exist, to be deviated, the reality of crosshair Border projected centre point will not be overlapped with preferred view central point.Therefore, when around treatment head longitudinal axis rotation therapy head, Crosshair follows treatment head to rotate, correspondingly, the center of crosshair can also be surrounded in the projected image of image acquisition element The ideal position of crosshair central projection point rotation.As shown in figure 4, showing when rotary frame is the first rack angle Degree (such as 0 degree, that is, treatment head in surface and portal imaging device in underface, and beam axis is in the vertical direction) when, ten Word cross hair multiple scheduled physical locations projected centre point, as these projected centre points fitting made of circle (dotted line) and The center of circle O ' of the circle.Wherein, center of circle O ' is central projection point (u of the crosshair in ideal position1′,v1'), radius R is The distance that the projection of the physical location at the center of crosshair is drifted out relative to the projection of its ideal position, these can be calculated It learns.
For second of offset situation, specifically, can be determined according to any of multiple projected images described first The cross hair of the physical location of the crosshair and its ideal position in angle deflects when frame angle.
Specifically, tungsten door is as defined by two pairs of moveable tungsten blocks, along the edge of the moveable tungsten block of first direction The straight line extended along second direction is formd in projection, the edge of moveable tungsten block is formed in projection in a second direction The straight line that extends along a first direction.In ideal position, two orthogonal cross hairs of crosshair are crosshair It is parallel with first direction and second direction respectively, it can be described as first direction cross hair and second direction cross hair.It observes any in Fig. 4 Actual projection images, for example, the crosshair projected image when treatment head is 0 degree.In the picture, first direction cross hair projects The parallel lines of the edge projection c of a and the moveable tungsten door of second direction are that have deflection angle, second direction cross hair projects b Parallel lines with the edge projection d of the moveable tungsten door of first direction are also to have deflection angle(with the angle of a and c essence It is identical), the deflection angleIt is easy to be calculated.
With continued reference to Fig. 4, it is practical projection centre O that first direction cross hair, which projects a and the center of second direction cross hair projection b, (u1,v1), connect practical projection centre O and preferred view center O'(u1′,v1') to get the vector arrived between O' point and 0 point (ushift, vshift) and vectorial angle β, wherein ushift=u1-u1', vshift=v1-v1′.Here, vectorial angle is to be in treatment head The line of the desired center projected position of crosshair and practical center projected position and first direction or second direction at 0 degree Angle.More specifically, vectorial angle β is aforementioned vector (ushift, vshift) and either direction between angle.It is shown in Fig. 4 Angle between vector and first direction, however, it is determined that angle between vector and second direction can also be with, two vectorial angles it Be 90 degree, it is subsequent using vectorial angle calculated when, as long as correspondence converted, this to those skilled in the art and Speech is well known.
It is calculated according to the example to Fig. 4, is in 0 degree when rotary frame is in the first frame angle and treatment head When, the desired center projected position (u of crosshair1′,v1') it is known, and when rotary frame is in the first frame angle When treatment head is in multiple predetermined positions simultaneously, the practical center projected position (u of crosshair1,v1) it is also known.Meanwhile The deflection angle of the edge projection c of first direction cross hair projection a and tungsten door when treatment head is in 0 degreeIt is known, practical throwing Vector (u between shadow center O and preferred view center O 'shift, vshift) be also known.
Above-mentioned confirmable offset parameter can be used online in the crosshair positioning of radiotherapy equipment.I.e. On the basis of previous embodiment, further includes:
When the rotary frame of radiotherapy equipment is 0 degree in the other angles and treatment head for being different from the first frame angle When, by the first frame angle and the central projection position of the physical location of when treatment head is in 0 degree crosshair Set (u1,v1) with the central projection position (u of its ideal position1′,v1') between vector (ushift, vshift) and this other Central projection position (the u of the new physical location of crosshair when frame anglenew,vnew), determine the crosshair New ideal position central projection position (u 'new,v′new)。
That is, when the rotary frame of radiotherapy equipment is in other angles and the treatment different from the first frame angle When head is in 0 degree, the central projection position of the new ideal position of the crosshair is determined by following formula:
u′new=unew-ushift
v′new=vnew-vshift。
Specifically, first at the other angles of rotary frame by radiation exposure crosshair measure crosshair newly Central projection position (the u of physical locationnew,vnew), and by it is above-mentioned calculating learn treatment head be 0 degree when O and Vector value (u between O'shift, vshift), therefore, the new ideal position of crosshair can be determined by above-mentioned formula Central projection position (u 'new,v′new)。
In above formula, ushiftAnd vshiftRotary frame be in when the first frame angle and treatment head are 0 degree just by It determines, the central projection position (u of the new physical location of crosshairnew,vnew) be also be easy to it is measured, therefore, ten Central projection position (the u ' of the new ideal position of word cross hairnew,v′new) be easy to be determined.
When the rotary frame of radiotherapy equipment is non-in the other angles and treatment head for being different from the first frame angle When zero degree α, the new reality of crosshair is first measured by radiation exposure crosshair at the other angles of rotary frame Central projection position (the u of positionnew,vnew), also, then determined by following formula in the ideal position of crosshair Heart projected position (u 'new,v′new):
In above formula, ushiftAnd vshiftRotary frame be in when the first frame angle and treatment head are 0 degree just by It determines, in addition, the central projection position (u of the new physical location of crosshairnew,vnew) it is also to be easy to measure, treatment Head-turned angle α is also known, and it is also that rotary frame, which is in vectorial angle β when the first frame angle and treatment head are 0 degree, Know, therefore, the central projection position (u ' of the new ideal position of crosshairnew,v′new) be easy to be determined.
In above formula, becauseSo above formula can be substituted with following formula:
u′new=unew-R cos(α-β)
v′new=vnew-R sin(α-β)
In above formula, because R, α, β are the central projection positions of known, crosshair new physical location (unew,vnew) it is also to be easy to measure, so the central projection position (u ' of the new ideal position of crosshairnew,v′new) logical Above formula is crossed to be easy to be determined.
In the foregoing embodiments, it is carried out according to the data in the first frame angle and when treatment head is 0 degree subsequent to ten The calculating of the central projection position of the ideal position of word cross hair.In other embodiments, if knowing in advance is: working as rotary frame When treatment head is in other angles (for example, α 0) of non-zero degree to the first frame angle simultaneously, can be determined according to preceding method Central projection (the u of the physical location of crosshairα0,vα0), the central projection (u ' of its ideal positionα0,v′α0), and according to ten Vector (u between the central projection of the physical location of word cross hair and the central projection of ideal positionshift-α0,vshift-α0), pass throughRadius value R is calculated.Then, if being determined at treatment head according to following formula Vectorial angle β when 0 degree between the central projection position of the ideal position of crosshair and the central projection position of physical location 1:
When treatment head turns to 1 angle of α, the β 1 that determined by above formula and is scanned in new position and obtain crosshair Central projection position (the u of physical locationnew,vnew), recycle following formula to determine the central projection position of the ideal position of crosshair It sets:
u′new=unew-R×cos(β1-α1)
v'new=vnew-R×sin(β1-α1)
The technical solution of the embodiment of the present invention is compared using projection of the beam irradiation crosshair in detection plane In the projection imaging of visible light source, image is more accurate, and resolution is higher；Also, it is not necessarily to artificial observation, improves the standard of identification True property.
Also, during the on-line correction of radiological installation, using the crosshair positional shift parameter having determined come On-line correction is carried out to practical projection coordinate's point, the mode compared to manual adjustment crosshair position is easier, more suitable Conjunction is frequently necessary to the case where correction.
Note that the above is only a better embodiment of the present invention and the applied technical principle.It will be appreciated by those skilled in the art that The invention is not limited to the specific embodiments described herein, be able to carry out for a person skilled in the art it is various it is apparent variation, It readjusts and substitutes without departing from protection scope of the present invention.Therefore, although being carried out by above embodiments to the present invention It is described in further detail, but the present invention is not limited to the above embodiments only, without departing from the inventive concept, also It may include more other equivalent embodiments, and the scope of the invention is determined by the scope of the appended claims.

Claims (8)

1. the localization method of crosshair in a kind of radiotherapy equipment, comprising:
In the state that the rotary frame of the radiotherapy equipment is in the first frame angle, the longitudinal axis around treatment head rotates institute Treatment head is stated, so that the treatment head is at least three predetermined positions, wherein pacify in the ray path in the treatment head Equipped with crosshair；
The crosshair is acquired through the corresponding projected image of radiation exposure by image acquisition element in each predetermined position；
According to any of the center of the crosshair in the projection and multiple projected images in each projected image It is a, determine offset of the physical location of the crosshair described in first frame angle relative to its ideal position；Wherein, The offset includes the offset and/or described between the center of the crosshair physical location and the center of its ideal position The physical location of crosshair and deflection of its ideal position in angle.
2. the localization method of crosshair according to claim 1, wherein according to the center of the crosshair in each institute Any of projection and the multiple projected images in projected image are stated, determines the cross described in first frame angle Offset of the physical location of cross hair relative to its ideal position, comprising:
According to central projection of the center of the crosshair in each projected image, the ideal of the crosshair is obtained The projected position at the center of position, and then determine the center of the physical location of the crosshair described in first frame angle Offset between the center of its ideal position.
3. the localization method of crosshair according to claim 2, wherein the center according to the crosshair exists Any of projection and multiple projected images in each projected image, obtain the ideal position of the crosshair The projected position at center, comprising:
Circular fit is carried out to the central projection of the center of the crosshair in each projected image, by the circle of fitting Center as the crosshair ideal position center projected position.
4. the localization method of crosshair according to claim 1, wherein according to the center of the crosshair in each institute Any of projection and the multiple projected images in projected image are stated, determines the cross described in first frame angle Offset of the physical location of cross hair relative to its ideal position, comprising:
According to any of multiple projected images, the physical location of the crosshair described in first frame angle is determined With deflection of its ideal position in angle.
5. the localization method of crosshair according to claim 1, wherein according to the center of the crosshair in each institute State any of central projection and the multiple projected images in projected image, determine in first frame angle described in The physical location of crosshair includes at least determining following offset parameter relative to the offset of its ideal position:
Central projection position (the u of the ideal position of the crosshair1', v1'), the treatment head is in multiple predetermined positions 0 degree when the crosshair in first direction cross hair the projection second direction vertical with the first direction on it is removable Deflection angle between the projection at the edge of dynamic tungsten doorCentral projection position (the u of the physical location of the crosshair1, v1) with the central projection position (u of its ideal position1', v1') between vector (ushift, vshift)；Or
The radius R for the circle being fitted by the multiple predetermined position and the treatment head are in the reality of crosshair at 0 degree Central projection position (the u of border position1, v1) with the central projection position (u of its ideal position1', v1') vectorial angle β.
6. the localization method of crosshair according to claim 5, wherein further include:
When the rotary frame of radiotherapy equipment is in other frame angles and the treatment head different from the first frame angle When in 0 degree, by the first frame angle and the center of the physical location of when treatment head is in 0 degree crosshair Projected position (u1, v1) with the central projection position (u of its ideal position1', v1') between vector (ushift, vshift), Yi Ji Central projection position (the u of the physical location of crosshair when other frame anglesnew,vnew), determine the spider Central projection position (the u ' of the ideal position of silknew,v′new)。
7. the localization method of crosshair according to claim 6, wherein when the rotary frame of radiotherapy equipment is in When other frame angles and the treatment head different from the first frame angle are in 0 degree, by the first frame angle and institute State the central projection position (u that treatment head is in the physical location of crosshair at 0 degree1, v1) with the center of its ideal position Projected position (u1', v1') between vector (ushift, vshift) and in other frame angles the crosshair reality Central projection position (the u of border positionnew,vnew), determine the central projection position (u ' of the ideal position of the crosshairnew, v′new) include:
When the rotary frame of the radiotherapy equipment is in other frame angles and institute different from the first frame angle State treatment head be in 0 degree when, the central projection position (u ' of the ideal position of the crosshairnew,v′new) it is by following public affairs Formula determines:
u′new=unew-ushift
v′new=vnew-vshift。
8. the localization method of crosshair according to claim 5, wherein further include:
When the rotary frame of radiotherapy equipment is in other frame angles different from first frame angle and described controls Head is treated when be in α degree angle, by first frame angle and the reality of when treatment head is in 0 degree crosshair Central projection position (the u of border position1, v1) with the central projection position (u of its ideal position1', v1') between vector (ushift, vshift) and in other frame angles the physical location of the crosshair central projection position (unew,vnew), really Central projection position (the u ' of the ideal position of the fixed crosshairnew,v′new) include:
When the rotary frame of radiotherapy equipment is α degree in other frame angles and treatment head for being different from the first frame angle When angle, the central projection position (u ' of the ideal position of the crosshairnew,v′new) it is to be determined by following formula:
Or determined by following formula:
u′new=unew-Rcos(α-β)
v′new=vnew-Rsin(α-β)。
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