EP0811991A1 - Kollimatoren - Google Patents

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Publication number
EP0811991A1
EP0811991A1 EP97302218A EP97302218A EP0811991A1 EP 0811991 A1 EP0811991 A1 EP 0811991A1 EP 97302218 A EP97302218 A EP 97302218A EP 97302218 A EP97302218 A EP 97302218A EP 0811991 A1 EP0811991 A1 EP 0811991A1
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EP
European Patent Office
Prior art keywords
radiation
target
collimator
source
impervious
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97302218A
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English (en)
French (fr)
Inventor
Moshe Ein-Gal
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Individual
Original Assignee
Individual
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Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP0811991A1 publication Critical patent/EP0811991A1/de
Withdrawn legal-status Critical Current

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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K1/00—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating
    • G21K1/02—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators

Definitions

  • the present invention relates to radiosurgery generally, and particularly to collimators used in stereotactic radiosurgery.
  • Stereotactic radiosurgery involves dose accumulation in a target volume by irradiating the target from a multiplicity of orientations with finely collimated beams.
  • stereotactic radiosurgery to render tissue necrotic is well established and various systems are currently used for stereotactic radiosurgery.
  • the prior art recognizes the need to confine radiation as much as possible to the target volume being treated. Generation of a desired dose pattern in and out of the target volume is the objective of a treatment plan. Such a plan takes into account limitations of the particular radiosurgical system used.
  • System types include a Gamma Unit which utilizes a multiplicity of Cobalt-60 sources arranged on a spherical surface, a linear accelerator (LINAC) which utilizes a proton beam source mounted on a rotating gantry, and a stationary generator for a charged particles beam.
  • LINAC linear accelerator
  • Treatment planning capabilities include selecting a dose level to the target, choosing collimators for beam shaping and a determination of beam orientations from which radiation is deposited in the target volume.
  • collimators for beam shaping and a determination of beam orientations from which radiation is deposited in the target volume.
  • Prior art stereotactic radiosurgery systems incorporate point sources for generating radiation beams (a point source is a radiation source which is significantly smaller than the target).
  • a collimator associated with a point source produces a diverging beam, i.e., the beam width increases with increased distance from the source.
  • Such a diverging collimator of the type used in conjunction with a LINAC or with a Gamma Unit, is made of a radiation impervious material configured to define a diverging radiation path.
  • the collimators associated with prior art stereotactic radiosurgery systems incorporate clear (non-blocked) radiation paths.
  • One of the consequences of such a beam profile is that prior art stereotactic radiosurgery methods are restricted for treating targets smaller than about 50 millimeters in diameter. The apparent reason is the increased radiation to healthy tissue.
  • the present invention seeks to provide improved apparatus and techniques for radiosurgery which represent a radical departure from the prior art.
  • the present invention includes a hollow path collimator, diverging or converging, which is capable of producing a hollow radiation beam at the target, thus providing an ability to irradiate mainly the target boundary. Causing tissue to be necrotic by irradiation mainly at the target boundary may have adequate clinical results while reducing the radiation dosage to healthy tissue.
  • the prior art does not describe a collimator for stereotactic radiosurgery incorporating a hollow radiation path.
  • a converging collimator may be used to produce a hollow radiation path.
  • An area source or a large source is a radiation source which is comparable in size or larger than the target.
  • An area source e.g., a Co-60 pack used for conventional radiotherapy, could be much cheaper for stereotactic radiosurgery than a LINAC or an array of 201 sources incorporated in the Gamma Unit.
  • a hollow radiation path collimator may be used to reduce the penumbra associated with a radiation beam produced by an area source. Since a single hollow radiation path reduces also the beam intensity (by blocking an internal portion of the beam), it may be advantageous to incorporate several hollow radiation paths in a single collimator. However, increasing the number of radiation paths may also increase the penumbra, suggesting that a desirable compromise between increasing beam intensity and increasing penumbra be reached. Such a compromise, for a given source and a given collimator material, may be obtained by selecting optimally the number of hollow paths and the associated geometrical properties.
  • the prior art does not describe the use of an area source and a collimator incorporating one or more hollow paths for stereotactic radiosurgery.
  • a collimator for use in radiosurgery including material which is generally radiation impervious and which is configured to define at least one at least partially hollow radiation path.
  • the collimator further includes a shield which is generally radiation impervious, the shield having formed therein a beam passageway, and at least one beam blocker which is generally radiation impervious, the at least one beam blocker being located in the beam passageway so as to form the at least one at least partially hollow radiation path.
  • a collimator for use in radiosurgery including material which is generally radiation impervious and which is configured to define a converging radiation path.
  • an irradiating device for use in radiosurgery including at least one source of radiation arranged to irradiate a target, and at least one collimator disposed between the at least one source of radiation and the target and including material which is generally radiation impervious and which is configured to define at least one at least partially hollow radiation path.
  • the at least one collimator includes a shield which is generally radiation impervious, the shield having formed therein a beam passageway, and at least one beam blocker which is generally radiation impervious, the at least one beam blocker being located in the beam passageway so as to form the at least one at least partially hollow radiation path.
  • an irradiating device for use in radiosurgery including at least one source of radiation arranged to irradiate a target, and at least one collimator disposed between the at least one source of radiation and the target and including material which is generally radiation impervious and which is configured to define at least one converging radiation path.
  • a method for radiosurgery including the steps of providing an irradiating device including at least one source of radiation arranged to irradiate a target, and at least one collimator disposed between the at least one source of radiation and the target and including material which is generally radiation impervious and which is configured to define at least one at least partially hollow radiation path, producing radiation beams with the irradiating device, and directing the radiation beams at a target volume from a multiplicity of orientations.
  • a method for radiosurgery including the steps of providing an irradiating device including at least one source of radiation arranged to irradiate a target, and at least one collimator disposed between the at least one source of radiation and the target and including material which is generally radiation impervious and which is configured to define at least one converging radiation path, producing radiation beams with the irradiating device, and directing the radiation beams at a target volume from a multiplicity of orientations.
  • a method for radiosurgery including the steps of providing at least one radiation source, collimating radiation from the at least one source to produce radiation beams which are at least partially hollow at the location of a target, and directing the at least partially hollow radiation beams at the target from a multiplicity of orientations to produce a radiation dose pattern having a substantially higher dose level at the boundary of the target and a substantially lower dose level at the interior of the target.
  • the method further includes the steps of collimating radiation from the at least one source to produce non-hollow radiation beams at the location of the target, and directing the non-hollow radiation beams at the target from a multiplicity of orientations to produce an additional radiation dose pattern having a substantially higher dose level at the interior of the target and a substantially lower dose level at the boundary of the target.
  • Fig. 1A illustrates a prior art radiation collimator
  • Figs. 1B, 1C and 1D illustrate three alternative embodiments of radiation collimators constructed and operative in accordance with a preferred embodiment of the present invention.
  • the radiation collimators of Figs. 1A - 1D are characterized in that they are formed of material which is generally radiation impervious.
  • the radiation collimator shown in Fig. 1A is configured to define a non-hollow and diverging radiation pathway.
  • Radiation collimators shown in Figs. 1B and 1D are configured to define an at least partially hollow radiation path.
  • the radiation collimator shown in Fig. 1C is configured to define a non-hollow and converging radiation pathway.
  • the hollow radiation path is useful for precise radiation treatment of targets in accordance with a preferred embodiment of the present invention whereby it is desired to irradiate the periphery of the target without substantially irradiating the center thereof, or whereby it is desired to irradiate a target using a large source of radiation.
  • large source of radiation and small source of radiation refer to the relative size of the radiation source compared to the size of the irradiated target.
  • a large source of radiation is comparable in size or larger than the target, while a small source of radiation is significantly smaller than the target.
  • Fig. 1A illustrates a collimator assembly including an exterior shield 10 defining a location 12 for a source of radiation, indicated by reference numeral 14.
  • the exterior shield 10 is formed with a bore 16 extending outwardly from location 12.
  • a collimating unit 20 is disposed in the bore 16.
  • the collimating unit 20 defines an unblocked diverging radiation beam pathway. It is noted that throughout the specification and claims the terms blocked and unblocked refer to the presence or absence of a substantial central beam obstruction, as distinct from the presence or absence of a material used for beam filtering.
  • Fig. 1B is preferably generally identical to that of Fig. 1A but, unlike the prior art, includes a beam blocker 22, which is generally radiation impervious, disposed within collimating unit 20.
  • Blocker 22 may have any arbitrary shape, such as conical.
  • the at least partially hollow radiation pathway in the collimator defines a diverging hollow beam outside the collimator.
  • Fig. 1C illustrates a collimator assembly including an exterior shield 30 defining a location 32 for a large source of radiation, indicated by reference numeral 34.
  • the source 34 is typically a pack of radioactive material, such as cobalt-60.
  • the exterior shield 30 is formed with a bore 36 extending outwardly from location 32.
  • a collimating unit 40 is disposed in the bore 36.
  • the collimating unit 40 is configured to form a non-hollow and converging radiation beam pathway. This pathway defines a non-hollow beam converging towards the focal point and diverging away from the focal point outside the collimator.
  • Fig. 1D is identical to that of Fig. 1C but also includes a beam blocker 42, which is generally radiation impervious, disposed within collimating unit 40.
  • Blocker 42 may have any arbitrary shape such as conical.
  • the at least partially hollow and converging radiation pathway in the collimator defines a beam outside the collimator which is converging and hollow near the collimator exit, non-hollow at the focus away from the collimator exit, and diverging and hollow at a distance from the focus.
  • any of the collimators of Figs. 1A - 1D may be used to form an interchangeable collimator radiation generator. Any of the collimator elements may be simply removed from the shield and another collimator element inserted in its place. Alternatively, the collimator elements may be rigidly embedded in a movable shield, wherein a particular collimator element may be selected by suitably moving the shield.
  • FIG. 2A, 2B and 2C illustrate three different cross beam profile configurations of radially symmetric beams in planes perpendicular to the corresponding beam axis.
  • Fig. 2A illustrates a cross beam profile of a non-hollow beam produced either by a prior art collimator according to Fig. 1A, a collimator of the present invention according to Fig. 1C or a collimator of the present invention according to Fig. 1D, at its focus.
  • the beam profile is characterized by a relatively high level of radiation near the center of the target, and the radiation level falls off rapidly at a certain distance from the center.
  • Fig. 2B illustrates a cross beam profile produced either by a collimator of the present invention according to Fig. 1B, or a collimator of the present invention according to Fig. 1D at a distance from its focus. It is noted that the beam profile is characterized by a relatively negligible level of radiation near the center of the profile, and a relatively high level generally at the periphery of the profile.
  • Fig. 2C illustrates a combined cross beam profile of a non-hollow beam and a hollow beam. It is noted that the beam profile of Fig. 2C is distinguished from the profile of Fig. 2A, in that the beam profile of Fig. 2C has a generally sharper or steeper fall off than that of Fig. 2A, when the hollow beam is produced by a collimator according to Fig. 1D. The steeper fall off may be useful in protecting neighboring tissue from unwanted radiation.
EP97302218A 1996-05-30 1997-04-01 Kollimatoren Withdrawn EP0811991A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IL11849696 1996-05-30
IL11849696A IL118496A0 (en) 1996-05-30 1996-05-30 Collimators

Publications (1)

Publication Number Publication Date
EP0811991A1 true EP0811991A1 (de) 1997-12-10

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Family Applications (1)

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EP97302218A Withdrawn EP0811991A1 (de) 1996-05-30 1997-04-01 Kollimatoren

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EP (1) EP0811991A1 (de)
JP (1) JPH1052510A (de)
CA (1) CA2201998A1 (de)
IL (1) IL118496A0 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006097254A2 (de) * 2005-03-12 2006-09-21 Smiths Heimann Gmbh Kollimator mit einstellbarer brennweite
CN102446571A (zh) * 2010-09-30 2012-05-09 上海世鹏实验室科技发展有限公司 一种自聚焦放射源装置及其辐射装置
CN107497060A (zh) * 2014-12-08 2017-12-22 南京中硼联康医疗科技有限公司 用于中子捕获治疗的射束整形体

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2331867A1 (fr) * 1975-11-14 1977-06-10 Commissariat Energie Atomique Collimateur pour faisceau de neutrons issus d'un reacteur nucleaire
DE3534686C1 (de) * 1985-09-28 1987-05-07 Bbc Reaktor Gmbh Einrichtung zum Durchstrahlen eines Objektes mit einer transportablen,thermische Neutronen erzeugenden Quelle
US4991189A (en) * 1990-04-16 1991-02-05 General Electric Company Collimation apparatus for x-ray beam correction
DE3934321A1 (de) * 1989-10-13 1991-04-18 Siemens Ag Roentgenroehre mit austrittsfenster
DE4130039A1 (de) * 1991-09-10 1993-03-11 Philips Patentverwaltung Anordnung zum erzeugen eines ausgedehnten roentgenstrahlenbuendels mit geringem querschnitt
US5332908A (en) * 1992-03-31 1994-07-26 Siemens Medical Laboratories, Inc. Method for dynamic beam profile generation

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2331867A1 (fr) * 1975-11-14 1977-06-10 Commissariat Energie Atomique Collimateur pour faisceau de neutrons issus d'un reacteur nucleaire
DE3534686C1 (de) * 1985-09-28 1987-05-07 Bbc Reaktor Gmbh Einrichtung zum Durchstrahlen eines Objektes mit einer transportablen,thermische Neutronen erzeugenden Quelle
DE3934321A1 (de) * 1989-10-13 1991-04-18 Siemens Ag Roentgenroehre mit austrittsfenster
US4991189A (en) * 1990-04-16 1991-02-05 General Electric Company Collimation apparatus for x-ray beam correction
DE4130039A1 (de) * 1991-09-10 1993-03-11 Philips Patentverwaltung Anordnung zum erzeugen eines ausgedehnten roentgenstrahlenbuendels mit geringem querschnitt
US5332908A (en) * 1992-03-31 1994-07-26 Siemens Medical Laboratories, Inc. Method for dynamic beam profile generation

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006097254A2 (de) * 2005-03-12 2006-09-21 Smiths Heimann Gmbh Kollimator mit einstellbarer brennweite
WO2006097254A3 (de) * 2005-03-12 2006-12-28 Smiths Heimann Gmbh Kollimator mit einstellbarer brennweite
US7436934B2 (en) 2005-03-12 2008-10-14 Smiths Heimann Gmbh Collimator with adjustable focal length
CN102446571A (zh) * 2010-09-30 2012-05-09 上海世鹏实验室科技发展有限公司 一种自聚焦放射源装置及其辐射装置
CN102446571B (zh) * 2010-09-30 2014-03-05 上海世鹏实验室科技发展有限公司 一种自聚焦放射源装置及其辐射装置
CN107497060A (zh) * 2014-12-08 2017-12-22 南京中硼联康医疗科技有限公司 用于中子捕获治疗的射束整形体
CN107497060B (zh) * 2014-12-08 2020-02-28 南京中硼联康医疗科技有限公司 用于中子捕获治疗的射束整形体

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Publication number Publication date
CA2201998A1 (en) 1997-11-30
JPH1052510A (ja) 1998-02-24
IL118496A0 (en) 1996-09-12

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