CN1315548C

CN1315548C - Shape-adaptive X-ray strengthening method and collimator

Info

Publication number: CN1315548C
Application number: CNB011055227A
Authority: CN
Inventors: 王增开
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-02-28
Filing date: 2001-02-28
Publication date: 2007-05-16
Anticipated expiration: 2021-02-28
Also published as: CN1310029A

Abstract

The present invention relates to an X-ray shape-adapting strength-regulating method and a collimator thereof, particularly to an X-ray shape-adapting strength-regulating method for medical radiotherapy. The collimator comprises an electron beam emitter, an X-ray generating tungsten target and a collimation mechanism, and is characterized in that the tungsten target is composed of small tungsten target elements arranged in rules. The shape-adapting strength-regulating goal is achieved by controlling the strength of electron beams and a scanning trace, and via the collimation and the match of the collimation mechanism. The present invention also discloses the collimation mechanism for realizing the method.

Description

A kind ofly realize method and the collimator apparatus thereof conformal intensity modulated to the X line

Technical field

The present invention relates to a kind of realize method and the collimator apparatus thereof conformal intensity modulated,, the invention still further relates to the collimation mechanism that is used to realize this method in particular for the conformal intensity modulated method of medical radiation treatment X line to the X line.

Background technology

Radiotherapy is one of main means of oncotherapy at present, has application fields, conformal modulating radiotherapy is the most practical method of science in the radiotherapy now, and want conformal modulating radiotherapy the best way is electron scanning, but the most sophisticated at present electromagnetic deflection scanning technique is difficult in this application, although at first the high energy electron line has certain penetration power to tissue, be mapped to human body deep tissue effect and bad but directly wear, secondly electronics line through its form of a stroke or a combination of strokes wire harness after the propagation of a segment distance throw on the launched field face will be edge dosage low in the middle of dosage high be the hot spot that Gaussian curve distributes, the dosage inequality that has caused the launched field face, obscure boundary, therefore be not suitable for conformal therapy, preferably carry out radiotherapy with the X line, but because the X line is made up of uncharged particle, be difficult to it be carried out deflection control with the electromagnetic deflection mode, the mode on the leafy smooth hurdle of now general employing realizes the conformal therapy to the X line, but still there is more problem in leafy smooth hurdle mode: at first, tens of to leads propelling and pull out and controlled by motor, therefore changing to the speed of another shape from a kind of shape can be very not fast; Secondly all figures can not be pieced together in leafy smooth hurdle, five-pointed star for example, unless at twice or more times finish; The 3rd, it can make intensity modulated therapy, but carries out cumbersome; The 4th, because multi-diaphragm collimator is made up of thin tungsten rod (5 millimeters or thinner), cause card article easily in motor process; The 5th, the given launched field edge of this Duola's chip collimator is step-like, with the true form of tumor be proximate meeting; In addition, it wears that to penetrate penumbra also bigger.

Summary of the invention

The objective of the invention is for overcome prior art not enough provide a kind of simple in structure, scanning speed fast, can carry out the method for X line conformal modulating radiotherapy and realize the collimation mechanism of this method the tumor of Any shape.

For achieving the above object, the present invention proposes following method: be used to produce the tungsten target of X line by many first tungsten target arrays of arranging by rule of forming of little tungsten target, electron beam is to the little tungsten target bombardment generation X of unit line, the X line that produces after collimator apparatus retaining removes scattered portion, on shadow surface, form and the regular small-sized photograph open country of the corresponding shape of little tungsten target identical permutation, when electron beam scans bombardment according to certain rules to little tungsten target unit, can produce the X line that scans by corresponding rule, by electron beam scanning rule and intensity are controlled, can carry out conformal intensity modulated control to the X line.

After adopting above-mentioned method, the intensity by control beam bombardment little tungsten target unit or the time of staying in little tungsten target unit, the exposure rate of may command X line; Can fit shape control and the medium and small tungsten target of little tungsten target element array unit bombarded selectively or do not bombard, can reach thus the X line is carried out conformal intensity modulated purpose.

In order to realize said method, the invention also discloses a kind of collimation mechanism: collimation mechanism is made up of the collimator and the control system that are provided with according to certain rules the collimation through hole of arranging and are fixed on the little tungsten target unit on the through hole, collimator comprises relatively-movable main collimator and time collimator, being respectively equipped with the quantity of arranging by matrix on main collimator and time collimator equates, the main collimation through hole of position correspondence and time collimation through hole, main collimation through hole and time collimation through hole axial direction parallel with directions of rays, time collimation through hole cross section on the inferior collimator is less than the cross section of the main collimation through hole on the main collimator, main collimator and time collimator are made for transmission material not, be fixed with identical with inlet area little tungsten target unit in main collimation through hole porch, main collimator places between radioactive source and the inferior collimator; Described collimator control system is by computer, dosage control mechanism, scanning voltage generation circuit, drive circuit and main collimator displacement motor and time collimator displacement motor are moved in the position, displacement drive circuit output main collimator displacement motor of control and time collimator displacement motor, main collimator displacement motor control respectively main collimator X to Y to the position, inferior collimator displacement motor control respectively time collimator X to Y to the position, the dosage controlling organization is controlled in computer output respectively, scanning voltage generation circuit, drive circuit is moved in the position.

Owing to adopted above-mentioned method and collimation mechanism, electron beam at first bombards and produces the X line being arranged on little tungsten target unit on the main collimator, the intensity of this X line is directly proportional with beam energy, and through on shadow surface, irradiating corresponding X line small-sized photograph open country behind the collimating device collimation; When electron beam scans little tungsten target unit, on shadow surface, can obtain corresponding X line sweep track, therefore according to the profile of tumor by control to electromagnetic deflection voltage, the track while scan and the intensity of control electron beam, and then the track while scan and the intensity that reach control X line satisfy conformal intensity modulated purpose.

The present invention is further elaborated below in conjunction with accompanying drawing, and provide the embodiment of collimation mechanism.

Description of drawings

Fig. 1 is a collimation mechanism example structure sketch map of the present invention;

Fig. 2 is that the position between main collimator and the inferior collimator through hole concerns sketch map;

Fig. 3 is the wild face sketch map of (0,1) for coordinate;

Fig. 3-1-Fig. 3-16 is main collimator and the sketch map of time collimator translation in the projection of roentgen radiation x face;

Fig. 4 is collimation mechanism control system theory diagram.

The specific embodiment

In the present embodiment, it is 12CM that main collimator 1 adopts thickness, the length of side is that the foursquare stereotype of 45CM is made, on stereotype, be evenly distributed with the square main collimation through hole 3 that 400 cross sections are 10mm * 10mm by matrix, the distance at center is 20mm between the Kong Yukong, be fixed with little tungsten target unit 5 at its arrival end, area is identical with inlet, inferior collimator 2 is by one and main collimator 1 equal area, thickness is that the stereotype of 8CM is made, by matrix distribution 400 cross sections being arranged equally above is square the collimation through hole 4 of 5mm * 5mm, position relation between main collimation through hole 3 and time collimation through hole 4 as shown in Figure 2, when the electron beam of launching from linear accelerator scans the little tungsten target unit 5 on the main collimator 1, will produce the X line in the little tungsten target unit 5 and appear the X line little Fang Ye identical with the square hole area from main collimation through hole 3 belows (is 10mm * 10mm), the little Fang Ye of these X lines arrives on time collimator 2 and further collimates through time collimation through hole 4, what appear from inferior collimation through hole 4 belows will be the little open country of X line of 5mm * 5mm, become 400 so little open countries when arriving the irradiation field face, in order further to illustrate the work process of collimator, we position the square hole on the collimator with rectangular coordinate system earlier, then the square hole coordinate on four angles is respectively (10,10), (9,10), (9,-9), (10,-9) referring to Fig. 2, below we are that the wild face of (0,1) point and periphery institute thereof return regionally to come the scanning work process of this collimator is elaborated with Fig. 3 for example with coordinate.

Fig. 3 partly scans branch to be finished for 16 times, is represented by Fig. 3-1-Fig. 3-16 respectively.In order to describe the work process of collimator, we specially extract a fritter in the coordinate (0,1) in the primary and secondary collimator and the zone of returning with Fig. 3 and represent.Fig. 3 has 16 component Fig. 3-1-Fig. 3-16, these 16 components are divided into the I-IV district again, the square hole of the main collimator of I district expression is in home position (upper left corner of region), to right translation 10mm, the III district is meant main collimator opposite direction translation (i.e. reach) 10mm towards the Y-axis arrow on the basis in II district to the II district main collimator of expression on the basis in I district.In like manner the IV district then is the 10mm that moves to left on the basis in III district.In fact through just having filled out only according to the emitted X-line Fang Ye of the small square hole of main collimator after such four steps in I-IV district, as if do not need to add time collimator according to having expired whole concentricity wild face.But collimation is problematic like this, the hole pitch-row of at first main collimator is from having only 10mm, therefore the X-ray in a certain square hole just might pass plumbous wall and penetrates and cause to wear greatly and penetrate penumbra from contiguous hole, second by 1 square centimeter little wild as the ultimate unit that constitutes wild face seemed bigger.

The adding of inferior collimator 2 solves these problems effectively, inferior collimator 2 is that unit carries out the right side, preceding, left, back four direction translation with 5mm, the electron beam of an accelerator of inferior collimator 2 every translations just scans one time by the hole 400 square holes of main collimator 1, after the four-wheel, the primary and secondary collimator is together to right translation 10mm (shown in the II district), inferior collimator 2 repeats the translation of the right side, preceding, left, back four direction again, certainly the width of translation is 5mm, and every translation once electron beam is also by hole scanning one time.Be not difficult to draw to make the X-line fill up whole launched field face master collimator 1 to carry out the right side, preceding, left, after four translations (translation is of a size of 10mm), inferior collimator 2 is wanted translation 16 times, electron beam also will be done 16 times scanning.

Generally speaking the concentricity wild face of 40cm * 40cm is made up of the little Fang Ye of 6400 5mm * 5mm (wild unit), and how much or have or not all and realized by the scanning electron line X-line dosage of each wild unit.When accelerator has obtained just can determine whether a certain wild unit will provide electron beam and what provide behind the shape of tumor and the strength information.

As shown in Figure 4, the control system of collimation mechanism is by computer PC dosage control mechanism 6, accelerating tube 9, scanning voltage generation circuit 7, drive circuit 8 and main collimator displacement motor A1 are moved in the position, A2 and time collimator displacement motor B1, B2 constitutes, computer PC is obtaining tumor information, analyze the back as calculated and launch the beam bombardment tungsten target 5 of respective strengths by customization dosage controlling organization 6 and accelerating tube 9 on the one hand, on the other hand by gated sweep voltage generating circuit 7 control sweep trace of electron beam, and by control position walking circuit 8 control step motors, main collimator displacement motor A1, the X that A2 controls main collimator respectively to Y to displacement, inferior collimator displacement motor B1, B2 control respectively time collimator X to Y to displacement.

Claims

1, a kind ofly realize the method conformal intensity modulated to the X line, comprise the electron beam emission source, be used to produce the tungsten target and the collimation mechanism of X line, it is characterized in that: the tungsten target array that tungsten target is made up of many little tungsten target units (5) of arranging by rule, electron beam produces the X line to little tungsten target unit (5) bombardment, the X line that produces after collimator apparatus retaining removes scattered portion, on shadow surface, form and arrange the regular small-sized photograph open country of corresponding shape with little tungsten target unit (5), when electron beam scans bombardment according to certain rules to little tungsten target unit (5), can produce the X line that scans by corresponding rule, the exposure rate of may command X line; Can fit shape control and the medium and small tungsten target of little tungsten target element array unit bombarded selectively or do not bombard, can reach thus the X line is carried out conformal intensity modulated purpose.

2, the realization according to claim 1 method conformal intensity modulated to the X line is characterized in that: the array that described little tungsten target unit (5) forms is fixedly installed on can be done on the mobile collimator of two dimension.

3, a kind of collimation mechanism of the method that is used to realize that the described X line of claim 1 is conformal intensity modulated, it is characterized in that: described collimation mechanism is formed by being provided with the collimation through hole of arranging according to certain rules and the collimator and the control system that are fixed on the little tungsten target unit (5) on the through hole, collimator comprises relatively-movable main collimator (1) and time collimator (2), being respectively equipped with the quantity of arranging by matrix on main collimator (1) and time collimator (2) equates, the main collimation through hole (3) of position correspondence and time collimation through hole (4), main collimation through hole (3) and time collimation through hole (4) axial direction parallel with directions of rays, time collimation through hole (4) cross section on the inferior collimator (2) is less than the cross section of the main collimation through hole (3) on the main collimator (1), main collimator (1) and time collimator (2) are made for transmission material not, be fixed with the little tungsten target unit (5) identical with inlet area in main collimation through hole (3) porch, main collimator (1) places between radioactive source and time collimator (2); Described collimator control system is by computer (PC), dosage control mechanism (6), scanning voltage generation circuit (7), drive circuit (8) and main collimator displacement motor (A1 are moved in the position, A2) and time collimator displacement motor (B1, B2), the main collimator displacement motor (A1 of displacement drive circuit (8) output control, A2) and time collimator displacement motor (B1, B2), main collimator displacement motor (A1, A2) control respectively main collimator (1) X to Y to the position, inferior collimator displacement motor (B1, B2) respectively control time collimator (2) X to Y to the position, dosage controlling organization (6) is controlled in computer (PC) output respectively, scanning voltage generation circuit (7), drive circuit (8) is moved in the position.

4, collimation mechanism according to claim 3 is characterized in that: the cross section of main collimation through hole (3) and time collimation through hole (4) is square, and main through hole (3) pitch-row that collimates equals 2 times of self length of sides.

5, collimation mechanism according to claim 4 is characterized in that: the sectional area of main collimation through hole (3) is 4 times of time sectional area of collimation through hole (4).

6, collimation mechanism according to claim 5 is characterized in that: the cross section of main collimation through hole (3) is 10mm * 10mm, and the sectional area of inferior collimation through hole (4) is 5mm * 5mm.