CN1178711A - Use of independent collimator in adaptive radiotherapy - Google Patents
Use of independent collimator in adaptive radiotherapy Download PDFInfo
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- CN1178711A CN1178711A CN 97116545 CN97116545A CN1178711A CN 1178711 A CN1178711 A CN 1178711A CN 97116545 CN97116545 CN 97116545 CN 97116545 A CN97116545 A CN 97116545A CN 1178711 A CN1178711 A CN 1178711A
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- collimator
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Abstract
The present invention relates to new method of adaptive radiotherapy. Based on the feature that the blades of independent collimator can move independently, the therapeutic planning system of tomographic or zoned mode designs the blade motion path, collimator rotating angle, radiation period and other radiotherapeutic parameters, and produces narrow bands suitable for target shape and regulated ray strength distribution through control computer. The said equipment has simple structure, low cost and adjustable narrow band width, and it can prevent overirradiation, underirradiation and irradiation of leaked ray to normal tissue of patient.
Description
The present invention relates to a kind of new method of tumor conformal therapy.
Conformal therapy (Conformal Radiotherapy, be called for short CR) is meant that the dose distribution that roentgenization forms is fit to target region shape, thereby can reduce the suffered damage of normal surrounding tissue, increases the tumor radioactive dose, reaches the purpose that improves the treatment ratio of gains.The notion of CR starts from the sixties, but is limited to technical conditions at that time, and the dose distribution that irradiation obtains often can not be fit to target region shape.From the initial stage eighties, the CR technology begins the clinical practice in developed country, because economic strength is limit, China does not still have hospital so far and carries out this technology.Theoretically, any method of enforcement CR must be able to be adjusted the launched field shape makes the projection of shape of its suitable target area in the launched field direction, and can regulate the ray density distribution in the launched field.The CR method of clinical implementation is concluded four classes at present: first beam dresser (Beam Modifier), it comprises block, clapboard and compensator.Block can the subregional ray of occlusion part, constitutes the irregular launched field that overlaps with the target area projection of shape.Clapboard can only make the ray density distribution aslope, thereby its accent is limited in one's ability by force.Compensator can obtain the intensity distributions of arbitrary shape by changing the ray transmitance.The major defect of this method is to manufacture time-consuming, pendulum position difficulty.Because each launched field shape is different, desirable strength distributes and also to be not quite similar, and is required to be special block of each launched field and compensator, and during each pendulum position, operator must move these heavy objects.It two is tomography treatment (Tomotherapy), and its typical case's representative is the NOMOS system of Peacock company, comprising the additional collimator of Mimic by name.Mimic is made of 40 pairs of switch bit blades.The on off state of computer control blade can form width and be 2 or 4cm, and length direction is the fillet open country of arbitrary shape.If the target area is divided into 2 or the wide thin layer of 4cm along a vertical bed lengthwise movement direction, then Mimic at first aims at first thin layer, and the on off state of blade is set, and makes the wild shape of fillet consistent with thin layer target area projection of shape.If in the roentgenization process, change the on off state of blade, just can adjust the irradiation time of the coverage field of this blade correspondence, promptly adjust its intensity.After finishing a thin layer irradiation, the staff advances machine room and moves bed 2 or 4cm, and Mimic aims at next thin layer irradiation.Like this, Mimic finishes the conformal therapy of each target area thin layer successively.The advantage of this method is that the staff is freed from the physical work of manufacturing, move block and compensator.Its shortcoming is to be thirty minutes long treatment time, and because the error of bed step motion may cause the thin layer adjacent region to be subjected to overdose or insufficient dose irradiation.It three is multi-diaphragm collimator (MultileafCollimator, be called for short MLC), and it is made of blade (20-40 to) many, and blade is waiting central plane projection width to be not less than 1cm.Each blade is by independent motor-driven, if the position of each blade that therefore computerizeds control can form the irregular step-like irradiation field that is fit to target region shape.Divide chip technology (Segmentaltechnique) or dynamic technique (Dynamic technique) to adjust leaf position in irradiation process if adopt, the arbitrfary point exposure rate is not directly proportional by the time that blade blocks with it in the launched field, reaches to transfer strong purpose.MLC has the advantage of NOMOS system, and can shorten treatment time to several minutes, so become the main method of implementing conformal therapy.Its shortcoming is a MLC machining accuracy height, the computer control complexity, and China's no this item technology is still come out; Cost an arm and a leg (about 300,000 dollars), domestic most of hospitals buy and have any problem; The leakage ray is arranged between blade, and the launched field penumbra of formation is big.It four is narrow beam scanning (Scanning Beam), and typical case's representative is a Scanditronix MM50 cyclotron.It is different from conventional accelerator, and its accelerated electron is drawn to practice shooting produces narrow beam X line, and the narrow beam direction is determined by magnetic field control electron beam exit direction.Narrow beam scanning target area, the arbitrfary point transmitted intensity is directly proportional with the scanning beam residence time in the zone.MM50 not only can make the X line and transfer by force, and can adjust ray energy and do electronics line accent strong.Its advantage is apparent, but because price extremely expensive (about 8,000,000 dollars), the whole world only has less than ten tame radiotherapy center to use so far.
The standard configuration of current clinac collimator system is independent collimator (Independant Collimator, be called for short IC), it is made of two pairs of blades, and four motors drive each blade respectively separately, can form the rectangular field of off-centring collimator axis.The two pairs of blades have at least a pair of blade to cross the collimator axis and to reach the about 10cm of offside from side maximum open position, another to blade can be from the maximum open position to the collimator axis or also can reach offside (Fig. 1).IC has been used for the wild radiotherapy of the wild and dynamic wedge shape of off-axis, but does not see the report that is used for conformal therapy.
The present invention's purpose is to utilize each blade self-movement characteristic of IC, adopt treatment parameters such as tomography or partitioned mode design collimator blade movement track, the collimator anglec of rotation, irradiation time by treatment planning systems, and form the wild group of the fillet that is fit to target region shape and adjust ray density distribution and implement conformal therapy by computer control.
Content of the present invention and main points comprise:
1. tomography mode
The ultimate principle of this mode is: IC can cross its axis at the blade of coordinate system Y direction at least.Along the paralleled by X axis direction, the target area projection of shape is divided into fillet (Fig. 2).Each fillet can shine with the fillet that IC forms is wild, i (i=1,2,3 ..., 8) and wild each leaf position of fillet is respectively X
I=X
I, i, X
II=X
II, i, Y
I=YP
i, Y
II=YP
I-1The accumulative effect of the wild irradiation of all fillets is equivalent to the irregular stepped launched field that MLC forms.The wild width of fillet can change anxious slow degree according to the target area edge shape be adjusted, and gets narrowly changing rapid zone, gets wide changing slow zone.Similar to the cutting apart of target area, the intensity distributions that launched field is required is divided into the wild intensity distributions of each fillet.On the one hand, if the movable axis (as GE, Simens company accelerator) of crossing of the X-direction blade of IC, then can adopt branch chip technology or the dynamic technique of similar MLC, control blade movement track in irradiation process is adjusted the time that the wild arbitrfary point of fillet is not blocked by blade.Because transmitted intensity is directly proportional with irradiation time, thereby can realize the wild intensity distributions of required fillet.The stack of the wild intensity distributions of all fillets obtains required intensity distributions.On the other hand,, then can adopt two kinds of solutions if the X-direction blade of IC can not be crossed axis (as Varian company accelerator): the one, the stopping means of cancellation IC makes blade be moveable to offside; The 2nd, an additional collimator is installed below IC, replace the X-direction blade of IC with it, cooperate the Y direction blade of IC to do suitable shape and transfer strong.
2. partitioned mode
Launched field intensity distributions available functions Φ (X, Y) expression (Fig. 3), X wherein, Y is the coordinate of both direction in the IC coordinate system.Launched field is fit to target region shape and can be regarded as the strong a kind of special case of accent, and it makes target area inner rays intensity is certain definite value, and transmitted intensity is zero outside the target area, if can realize that therefore (X Y), can reach suitable shape and the strong dual purpose of accent to intensity distributions Φ.(X Y) can be decomposed into X to Φ, one group of equal strength district that iso-intensity curve comprises in the Y plane.Each intensity region all can be divided into one group of fillet (as the fillet around 5 intensity region).Divide the direction of fillet and select, should be able to make the number of fillet reduce to minimum (as the direction of arrow of 100 intensity region).IC forms the every group of fillet open country that is fit to varying strength district shape successively, the collimator anglec of rotation is divided direction according to fillet and is determined, exposure rate is its respective value (as 5 intensity region irradiation 5) in the minimum intensity district, shines the difference (as 100 intensity region irradiation 10) of adjacent intensity region in other intensity region.Some very little intensity region can need not to be divided into fillet with a little wild irradiation.
Advantage of the present invention and good effect are: compare with existing four kinds of methods, demonstrate different superioritys, as alleviating staff's labor intensity greatly, overcome the problem of wild adjacent region overdose of fillet or insufficient dose irradiation, method is simple, has reduced the complexity of system, avoided leaking between adjacent blades roentgenization patient normal structure, the wild width of fillet can be regulated arbitrarily, greatly reduces cost price etc., so the new method of a kind of conformal therapy that tallies with the national condition of can yet be regarded as.
Description of drawings:
Fig. 1----independent collimator structural representation
Wherein: the 1----radiographic source
2----Y direction of principal axis collimator blade Y
I
3----Y direction of principal axis collimator blade Y
II
4----X direction of principal axis collimator blade X
I
5----X direction of principal axis collimator blade X
II
Launched field Fig. 2----target area that the 6----collimator forms is divided into fillet and the wild position view of fillet
Wherein: 1 to 8 is the wild numbering of fillet
The 9----target area;
X
I, 1To X
I, 8Be directions X X
IBlade is forming fillet when wild
Coordinate position;
X
II, 1To X
II, 8Be directions X X
IIBlade is forming fillet when wild
Coordinate position;
YP
0To YP
8Be two blade Y of Y direction
I, Y
IIForming fillet
Coordinate position when wild; The wild position view of Fig. 3----ray equal strength area distribution and fillet
Wherein: 5,10 ..., 50 ..., 90,100 each transmitted intensity curve of expression
The relative intensity value;
1 '----intensity level is 5 iso-intensity curve;
2 '----intensity levels are 10 iso-intensity curve;
3 '----intensity levels are 50 iso-intensity curve;
4 '----intensity levels are 90 iso-intensity curve;
5 '----intensity levels are 100 iso-intensity curve;
X
I, 1To X
I, 13Be exposure rate be 5 regional the time, each fillet
Wild blade X
IThe position;
X
II, 1To X
II, 13Be exposure rate be 5 regional the time, each fillet
Wild blade X
IIThe position
Claims (4)
1. the application of independent collimator in conformal therapy, it is characterized in that only using independent collimator or additional collimator to cooperate independent collimator, adopt tomography mode or partitioned mode to design treatment parameters such as collimator blade movement track, the collimator anglec of rotation, irradiation time by treatment planning systems, and implement treatment by computer control.
2. according to claims 1 application of described independent collimator in conformal therapy, it is characterized in that the tomography mode is that target area and launched field intensity distributions are divided into one group of fillet, form launched field that is fit to the fillet shape and the intensity distributions of adjusting the fillet open country with independent collimator.
3. according to claims 1 application of described independent collimator in conformal therapy, it is characterized in that partitioned mode is that the launched field intensity distributions is decomposed into one group of equal strength district, be fit to each equal strength district shape with one group of fillet open country respectively, give the doses irradiation.
4. according to claims 1 application of described independent collimator in conformal therapy, it is characterized in that to adjust its width arbitrarily when the fillet open country is divided.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 97116545 CN1178711A (en) | 1997-09-17 | 1997-09-17 | Use of independent collimator in adaptive radiotherapy |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 97116545 CN1178711A (en) | 1997-09-17 | 1997-09-17 | Use of independent collimator in adaptive radiotherapy |
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| Publication Number | Publication Date |
|---|---|
| CN1178711A true CN1178711A (en) | 1998-04-15 |
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| CN 97116545 Pending CN1178711A (en) | 1997-09-17 | 1997-09-17 | Use of independent collimator in adaptive radiotherapy |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100363069C (en) * | 2003-03-13 | 2008-01-23 | 株式会社东芝 | Multiblade collimator |
| CN100569316C (en) * | 2003-07-08 | 2009-12-16 | 埃莱克特公司 | Multi-blade collimator |
| CN101303908B (en) * | 2008-06-24 | 2011-02-16 | 西南技术工程研究所 | X ray collimator apparatus |
| CN101246757B (en) * | 2007-08-23 | 2011-07-06 | 中国医学科学院肿瘤医院 | Generation method of dynamic independent collimating device collimation block movement path |
| CN101339819B (en) * | 2007-07-05 | 2012-03-07 | 同方威视技术股份有限公司 | Remote controllable collimator with four parts independently moving |
| CN101329923B (en) * | 2007-06-21 | 2012-07-11 | 同方威视技术股份有限公司 | Dual-purpose collimating device with seam |
| CN104436450A (en) * | 2013-09-25 | 2015-03-25 | 苏州雷泰医疗科技有限公司 | Light limiting device for radiotherapy device and radiotherapy device |
| CN105727448A (en) * | 2014-12-11 | 2016-07-06 | 苏州雷泰医疗科技有限公司 | Grating apparatus for radiation treatment |
| CN110523008A (en) * | 2019-07-08 | 2019-12-03 | 戴建荣 | Multi-diaphragm collimator blade design method and system and blade and multi-diaphragm collimator |
-
1997
- 1997-09-17 CN CN 97116545 patent/CN1178711A/en active Pending
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100363069C (en) * | 2003-03-13 | 2008-01-23 | 株式会社东芝 | Multiblade collimator |
| CN100569316C (en) * | 2003-07-08 | 2009-12-16 | 埃莱克特公司 | Multi-blade collimator |
| CN101329923B (en) * | 2007-06-21 | 2012-07-11 | 同方威视技术股份有限公司 | Dual-purpose collimating device with seam |
| CN101339819B (en) * | 2007-07-05 | 2012-03-07 | 同方威视技术股份有限公司 | Remote controllable collimator with four parts independently moving |
| CN101246757B (en) * | 2007-08-23 | 2011-07-06 | 中国医学科学院肿瘤医院 | Generation method of dynamic independent collimating device collimation block movement path |
| CN101303908B (en) * | 2008-06-24 | 2011-02-16 | 西南技术工程研究所 | X ray collimator apparatus |
| CN104436450A (en) * | 2013-09-25 | 2015-03-25 | 苏州雷泰医疗科技有限公司 | Light limiting device for radiotherapy device and radiotherapy device |
| CN104436450B (en) * | 2013-09-25 | 2018-07-31 | 苏州雷泰医疗科技有限公司 | Radiotherapy unit light limiting means and radiotherapy unit |
| CN105727448A (en) * | 2014-12-11 | 2016-07-06 | 苏州雷泰医疗科技有限公司 | Grating apparatus for radiation treatment |
| CN105727448B (en) * | 2014-12-11 | 2018-06-19 | 苏州雷泰医疗科技有限公司 | A kind of radiatherapy grid device |
| CN110523008A (en) * | 2019-07-08 | 2019-12-03 | 戴建荣 | Multi-diaphragm collimator blade design method and system and blade and multi-diaphragm collimator |
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