EP0021441B1 - Elektronenbeschleuniger zur Röntgenstrahlentherapie - Google Patents

Elektronenbeschleuniger zur Röntgenstrahlentherapie Download PDF

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Publication number
EP0021441B1
EP0021441B1 EP80103661A EP80103661A EP0021441B1 EP 0021441 B1 EP0021441 B1 EP 0021441B1 EP 80103661 A EP80103661 A EP 80103661A EP 80103661 A EP80103661 A EP 80103661A EP 0021441 B1 EP0021441 B1 EP 0021441B1
Authority
EP
European Patent Office
Prior art keywords
electron
energy
filter plate
target
low
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.)
Expired
Application number
EP80103661A
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German (de)
English (en)
French (fr)
Other versions
EP0021441A3 (en
EP0021441A2 (de
Inventor
Leonhard Dipl.-Phys. Taumann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Original Assignee
Siemens AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP0021441A2 publication Critical patent/EP0021441A2/de
Publication of EP0021441A3 publication Critical patent/EP0021441A3/de
Application granted granted Critical
Publication of EP0021441B1 publication Critical patent/EP0021441B1/de
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • 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
    • G21K1/10—Scattering devices; Absorbing devices; Ionising radiation filters

Definitions

  • the invention relates to a low-energy electron accelerator for X-ray therapy with an evacuated acceleration tube, with a target exposed to the electron beam made of a material with a high atomic number, with a collimator, with a profiled compensating body arranged centered on the axis of symmetry of the collimator's aperture and with a filter plate.
  • the device on which the above-mentioned DE-A-2 727 275 is based is to use a deflection magnet which deflects it by 270 ° and focuses the electrons of predetermined energy in the electron beam. In this way, the target is only hit by electrons of the respectively set (high) acceleration energy. This significantly improves the radiation quality.
  • a deflection magnet is extremely complex in its construction and also requires a correspondingly large space between the beam exit window of the acceleration tube and the target. This in turn affects the size of the accelerator in an undesirable manner.
  • a deflection magnet will therefore only be provided for electron accelerators that achieve a relatively high energy. A certain inhomogeneity of the energy distribution over the radiation cross-section at different penetration depths can be accepted, since at the high energies under consideration tissue is to be attacked not far in the subcutaneous area, but far below.
  • Such a high-energy linear accelerator with a deflection magnet should not be considered in the following.
  • the electron accelerator mentioned at the outset is known from the reference “Radiology” 115, pages 475-477, May 1975. This works with an X-ray energy of 4 MeV and does not need a magnet.
  • the acceleration tube is followed by a target that generates X-rays when electrons collide. After passing through a primary collimator, this strikes a profiled compensating body which consists of a heavy metal, namely lead. After the throughput of an ionization chamber and a secondary collimator, the X-rays fall on a disk-shaped filter, which is made of a low-order metal, namely brass.
  • This filter is intended to remove an unpleasant property of such a low-energy electron accelerator; namely, it is said to level the so-called “hot spots” or “horns” in the energy distribution of the X-ray beam measured across the cross section.
  • These "hot spots” or “Hömer” can lead to increased doses and thus to burns during therapy in the subcutaneous area.
  • This filter therefore selectively reduces the areas with a high radiation dose at the edges of large radiation fields.
  • Such a solution to the problem of "hot spots” or “horns” cannot be used according to the protective provisions of a number of countries that the dose and dose rate changed by the additional filter are not recorded by the monitor.
  • DE-A-2 533 348 relates to a target which is composed of three layers. While the first layer consists of a medium atomic number material and is used to generate X-rays, the middle layer consists of a material of low atomic number and serves as an electron absorber. As the last layer, this layer is followed by one made of a material with a high atomic number, which is preferably used to absorb X-ray quanta of lower energy. The use of linear accelerators with low energy is not dealt with in this reference.
  • DE-B-2441 986 discloses a large aperture x-ray generator that generates a wide, diffuse x-ray cone.
  • the target is applied to a low atomic number plate, preferably aluminum, and there is an aluminum window behind this support plate.
  • This publication does not show that the support plate or the window have a function other than allowing the X-ray radiation of the target to pass through well.
  • the invention has for its object an electron accelerator of the beginning ge named type, which does not need a magnet and works with an electron energy in the range of 2 to 10 MeV, so that the hardening of the X-rays is achieved with the simplest possible means and at the same time the most uniform possible energy distribution over the radiation cross-section, whereby a practical solution is found should.
  • the compensating body is made from a material of a low atomic number
  • an electron absorber known per se is connected downstream of the target
  • the filter plate is inserted between the electron absorber and the compensating body and is made of heavy metal with high absorption for low-energy X-rays and with low absorption for higher-energy X-rays, the filter plate having an equivalent lead of at least 1 mm at an electron energy of 2 to 10 MeV.
  • the compensating body made of a material with a higher atomic number, such as. B. of copper or even lead. Hardening of the X-rays by the compensating body would then have led to an undesired hardening which decreases radially in the cone of radiation due to the different thickness of the profiled compensating body.
  • the filter plate is not hit by electrons because of the upstream electron absorber. It cannot therefore appear as a competing target. Under this condition, the choice of filter material can only be based on its suitability for hardening the X-rays. In addition, the compensation body downstream of the filter plate in the beam direction is hit by X-rays, which is largely homogenized by the upstream filter plate.
  • a particularly simple construction results if the target is attached to the side of the electron absorber facing the acceleration tube.
  • the electron absorber supports whose dimensions must be kept much stronger than that of generally only about 3 mm. strong lead foil existing target, this off. This construction therefore results in an improved mechanical protective function.
  • the figure shows a sectional view through the last two cavity resonators of an acceleration tube, through the target and through the collimator.
  • the two last, cavity-shaped cavity resonators 1, 2 of an acceleration tube 3 of a linear accelerator are shown cut open along their axis of symmetry 4.
  • the axis of symmetry of the cavity resonators coincides with the electron beam 5.
  • the outlet opening 6 of the last cavity 2 is closed by a metal plate with high thermal conductivity, the electron absorber 7, in the exemplary embodiment a 20 mm thick copper plate.
  • This electron absorber 7 is the last resonant cavity 2 gas-tight up - soldered.
  • the electron absorber 7 At the location of the electron absorber 7 where the electron beam 5 would strike, it is provided with a disk-shaped depression, into which a target 8 only a few tenths of a millimeter thick is soldered.
  • the electron absorber 7 is provided with cooling channels (not shown) which end in hose connections 9, 10 for connection to a cooling system (not shown here for the sake of clarity).
  • the electron absorber 7 carries a filter plate 11 on the side facing away from the target 8.
  • the collimator 12 is arranged with a conical opening 13 for the passage of the maximum X-ray field 14 to be used .
  • a compensating body 15 is fastened to the collimator 12, by means of which the intensity profile of the X-ray radiation following a Gaussian distribution curve is compensated for over the entire cross-section of the X-ray field 14 that is maximally used.
  • the electrons accelerated by the acceleration tube 3 strike the target 8 which closes the exit opening 6 of the acceleration tube 3.
  • X-ray brake radiation is generated in the target.
  • the waste heat generated in the target is released to the electron absorber via the solder connection between the target 8 and the electron absorber 7 and flows off there to a coolant.
  • the electrons passing through the target are braked and absorbed in the material of the electron absorber 7 located behind them. For this reason, in the beam direction behind the electron absorber 7 ordered filter plate 11 also no further X-rays are generated.
  • a material has therefore been used for the filter plate 11, which has been selected solely on the basis of its absorption properties - the largest possible absorption factor in the range of low-energy X-ray quanta of 1 to 3 MeV and the smallest possible absorption factor in the range of higher-energy X-ray quanta above 3 MeV.
  • the heavy metals lead, tantalum, gold, tungsten and uranium are particularly suitable for this purpose.
  • a 2 mm thick filter plate made of lead was used for an electron energy of approx. 4 MeV. Since the filter plate 11 is equally strong over the entire maximum radiation cross section to be used, the hardening effect for the radiation is also uniform over this entire radiation cross section.
  • the compensating body following in the beam direction needs and should therefore no longer show any hardening effect. It can therefore be made of a material with a low atomic number. be made, in which the absorption over the entire occurring X-ray energy spectrum is approximately the same size. Aluminum is particularly well suited for this.
  • the advantage of this design can be seen in particular in the fact that the disadvantages with regard to the beam quality associated with the omission of the complex and bulky 270 ° deflection and focusing magnet for the electron beam 5 can largely be compensated for by the compensating body 15 made of a material with a low atomic number, e.g. B. aluminum, and a filter plate 11 is used behind the electron absorber 7, the X-ray quanta of lower energy preferably absorbed.
  • the design is not only decidedly cheaper, it also leads to devices that are much smaller and easier to position in medical applications.

Landscapes

  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Particle Accelerators (AREA)
  • Radiation-Therapy Devices (AREA)
  • Apparatus For Radiation Diagnosis (AREA)
EP80103661A 1979-07-03 1980-06-27 Elektronenbeschleuniger zur Röntgenstrahlentherapie Expired EP0021441B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2926883A DE2926883A1 (de) 1979-07-03 1979-07-03 Elektronenbeschleuniger
DE2926883 1979-07-03

Publications (3)

Publication Number Publication Date
EP0021441A2 EP0021441A2 (de) 1981-01-07
EP0021441A3 EP0021441A3 (en) 1981-01-14
EP0021441B1 true EP0021441B1 (de) 1985-04-17

Family

ID=6074828

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80103661A Expired EP0021441B1 (de) 1979-07-03 1980-06-27 Elektronenbeschleuniger zur Röntgenstrahlentherapie

Country Status (5)

Country Link
US (1) US4300055A (enrdf_load_stackoverflow)
EP (1) EP0021441B1 (enrdf_load_stackoverflow)
JP (1) JPS5614199A (enrdf_load_stackoverflow)
CA (1) CA1139022A (enrdf_load_stackoverflow)
DE (2) DE2926883A1 (enrdf_load_stackoverflow)

Families Citing this family (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3138731A1 (de) * 1981-09-29 1983-04-07 Siemens AG, 1000 Berlin und 8000 München Ueberwachungsanordnung fuer die beschleunigungsenergie eines elektronenbeschleunigers
FR2558327B1 (fr) * 1984-01-17 1986-04-25 Cgr Mev Accelerateur de particules multiregimes
NL9000896A (nl) * 1990-04-17 1991-11-18 Philips Nv Roentgenstraling absorberend filter.
FR2728472B1 (fr) * 1994-12-27 1997-03-28 Ge Medical Syst Sa Appareil de radiotherapie utilisant un accelerateur lineaire d'electrons a tres haute frequence et des moyens de protection hors champ utile
AU7137500A (en) 1999-07-21 2001-02-13 Jmar Research, Inc. High collection angle short wavelength radiation collimator and focusing optic
WO2001007939A1 (en) * 1999-07-21 2001-02-01 Jmar Research, Inc. Collimator and focusing optic
RU2245588C2 (ru) * 2003-02-14 2005-01-27 Белугин Владимир Михайлович Источник проникающего излучения
CN1822239B (zh) * 2005-02-17 2010-06-23 Ge医疗系统环球技术有限公司 滤波器和x射线成像设备
US7483518B2 (en) * 2006-09-12 2009-01-27 Siemens Medical Solutions Usa, Inc. Apparatus and method for rapidly switching the energy spectrum of diagnostic X-ray beams
CN101303909B (zh) * 2007-05-11 2013-03-27 Ge医疗系统环球技术有限公司 滤波器单元,x射线管单元和x射线成像系统
FR2926924B1 (fr) * 2008-01-25 2012-10-12 Thales Sa Source radiogene comprenant au moins une source d'electrons associee a un dispositif photoelectrique de commande
CN101658429A (zh) * 2008-08-29 2010-03-03 Ge医疗系统环球技术有限公司 X光散射线阻挡叶片的调节装置
CN101853710B (zh) * 2009-03-31 2014-11-19 Ge医疗系统环球技术有限公司 滤波器及利用该滤波器的x射线成像设备
US20140264065A1 (en) * 2013-03-15 2014-09-18 Varian Medical Systems, Inc. Energy degrader for radiation therapy system
GB201414393D0 (en) * 2014-08-13 2014-09-24 Nikon Metrology Nv Z-ray beam collimator
DE102018112054B4 (de) * 2018-05-18 2023-02-09 Yxlon International Gmbh Röntgenröhre mit Kollimator und Kollimatorvorrichtung für geschlossene Röntgenröhre

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2533348A1 (de) * 1974-12-18 1976-06-24 Atomic Energy Of Canada Ltd Aus einzelnen schichten aufgebautes target zur bremsstrahlungserzeugung

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1153324A (fr) * 1955-05-18 1958-03-05 Thomson Houston Comp Francaise Cible pour microscope à rayons x
CA1007767A (en) * 1973-09-04 1977-03-29 Machlett Laboratories Broad aperture x-ray generator
US4121109A (en) * 1977-04-13 1978-10-17 Applied Radiation Corporation Electron accelerator with a target exposed to the electron beam
CA1102018A (en) * 1978-01-09 1981-05-26 Philip Mchugh Unitary self shielded, self filtered and flattened bremsstrahlung photon source assembly for radiotherapy use

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2533348A1 (de) * 1974-12-18 1976-06-24 Atomic Energy Of Canada Ltd Aus einzelnen schichten aufgebautes target zur bremsstrahlungserzeugung

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Electromedica Nr. 3. 1979 (Auslieferungsdatum 14.08.79 siehe Eingabe 76 vom 19.05.83), W.E. SCHIEGL "Mevatron - das neue Konzept" S. 124-126 *
Radiology Nr. 115, Mai 1975, R.J. BOGE et al."Accessory Beam Flattering Filter for the Varian Clinac-4 Linear Accelerator" S. 475-477 *

Also Published As

Publication number Publication date
JPS5614199A (en) 1981-02-10
EP0021441A3 (en) 1981-01-14
DE3070505D1 (en) 1985-05-23
DE2926883A1 (de) 1981-01-22
US4300055A (en) 1981-11-10
CA1139022A (en) 1983-01-04
EP0021441A2 (de) 1981-01-07
JPS6312280B2 (enrdf_load_stackoverflow) 1988-03-18

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