Classifications

• • 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
• • 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
  • A61N5/1078—Fixed beam 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
  • A61N2005/1061—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam using an x-ray imaging system having a separate imaging source
• • 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
  • A61N2005/1085—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy characterised by the type of particles applied to the patient
  • A61N2005/1087—Ions; Protons

Definitions

• the invention relates to a medical radiation therapy device, in particular for particle beam therapy.
• a particle beam that is guided in a radiation channel and enters the radiation therapy room via an exit window of the radiation channel is produced in a suitable accelerator.
• the target volume to be irradiated in the patient to be treated (for example a tumor) must in this case be aligned as accurately as possible to the isocenter of the irradiation device.
• the patient is usually immobilized on a patient couch while the radiation therapy is being carried out, and so a movement of the patient is excluded as far as possible and the target volume is stationary with reference to the particle beam.
• Radiation therapy units are, for example, disclosed in US 4,726,046 and in DE 100 10 523 Al.
• the imaging system Before beginning the radiation therapy, it is customary to use an imaging system to undertake a positional verification in order to balance the current actual position of the target volume with a position of the target volume forming the basis of the therapy planning. That is to say, the imaging diagno ⁇ sis is used to check whether the target volume is actually located at the supposed location.
• the imaging system in this case typically comprises a radiation source, in particular a X-ray radiation source, and a suitable detector.
• the posi ⁇ tional verification is undertaken directly before carrying out the radiation therapy, while the patient is already lo- cated in the immobilized position for the radiation therapy. In this case, the imaging system requires a certain free space about the target volume.
• the X-ray radiation source is here arranged, for example, in front of the end of the radia- tion channel or in the immediate vicinity or around the end of the radiation channel. Consequently this requisite free space necessitates that the end of the radiation channel be spaced from the target volume by a certain air gap that is of the order of magnitude of approximately 1.0 m.
• the exit window therefore is at a not inconsid ⁇ erable distance from the target volume to be irradiated. How ⁇ ever, treating the target volume as precisely as possible re- quires aiming at positioning the exit window as close as pos ⁇ sible to the target volume, since the particle beam that is guided inside the radiation channel in a vacuum loses focus appreciably at the air.
• the accuracy of the irradiation is consequently reduced, and so there is a risk of irradiating healthy tissue as well.
• the radiation exit window is brought up as close as possible to the target volume. Because of the cramped space, the imaging can in this case be carried out only from certain directions.
• a medical radiation therapy device having a radiation channel, also denoted as radiation tube, that extends in the di ⁇ rection of radiation and has at the end an exit window for a particle beam.
• the position of the exit window is displace- able in this case in the direction of radiation. Owing to the displaceability of the exit window, the latter can be displaced in a direction of radiation relative to the target volume of the patient which is stationary during the positional verification and the irradiation, and the spacing between the target volume and the exit window can thereby be varied.
• the exit window When carrying out the radiation therapy, the exit window is firstly moved into a retracted position such that as large a free space as possible is achieved between the exit window and the target volume to be irradiated. Subse- quently, the imaging system is used to undertake a positional verification. Since the exit window is in the retracted posi ⁇ tion, adequate free space is made available for the imaging system, and so a positional verification can be carried out from any position. Subsequent to the positional verification, the exit window is moved into a front position as close as possible to the target volume, and so the air space between the exit window and target volume is as slight as possible.
• the lengthening of the ra ⁇ diation channel means that the particle beam in the vacuum is up very close to the target volume to be irradiated, and so the particle beam outside the radiation channel loses focus as little as possible owing to the reaction with the air.
• the exit window can be moved in the direction of radiation approximately up to the length of the requisite free space for the imaging system.
• This longitudinal mobility is therefore, in particular, ap ⁇ proximately 0.5 - 1 m.
• a detector block is fastened in front of the exit window, that is to say ar- ranged in a stationary fashion with reference to the exit window, particularly directly at the radiation channel or radiation tube.
• This detector block in this case comprises, in particular, at least one detector for the particle beam, and passive radiation elements. Owing to the stationary positioning, the detector block is therefore displaced in a longitu ⁇ dinal direction together with the exit window. Owing to the direct arrangement at the exit window, the detector and the passive radiation elements can be adjusted optimally with reference to the particle beam.
• the radia- tion channel has at least one longitudinally variable seg ⁇ ment.
• This section is expediently designed here telescopi- cally.
• it is of elastic design such that its length is variable ow ⁇ ing to the elasticity.
• the elastic segment is here designed in the manner of a corrugated hose or corru ⁇ gated tube. A high degree of longitudinal variability of the radiation channel is attained with comparatively simple structural means owing to these measures.
• the segment whose length can be varied has a reduced diameter by comparison with a front region of the radiation channel.
• the front region of the radiation channel is orientated towards the exit window in this case.
• the req- uisite energy for the longitudinal adjustment is kept as slight as possible owing to this measure, since, specifi ⁇ cally, an ultra high vacuum of approximately 10 ⁇ 8 mbar pre ⁇ vails in the interior of the radiation channel.
• the inner volume of the radiation channel is increased, and this leads to an additional pressure reduction. Since work is done against at ⁇ mospheric pressure in the event of lengthening, the use of a segment of lesser diameter keeps the further pressure drop, and thus the requisite energy for the longitudinal adjust- ment, slight.
• the diameter of the segment is here expediently only 0.2 to 0.7 times the diameter of the radiation channel in the front region.
• the diameter of the segment is less than half as large as that of the front region.
• the latter is fastened between two sections of the radiation channel via flanges.
• the bearing is preferably such that the respective longitudinal position of the exit window can be fixed. This ensues, for example, via mechanical locking or blocking elements or else by the blocking of a drive unit, which are provided for the mobility.
• the front region is movable by motor, pneumatically or hydraulically .
• a motor is provided here that has a transmission, a linear motor, a pneumatically or hydraulically extendable cylinder, etc.
• This drive is expediently designed here in such a way that it can lock or hold the front region in the respective longitudinal position with the aid of a sufficiently high level of retain ⁇ ing force .
• figure 1 shows a partially illustrated radiation therapy de- vice in accordance with a first alternative
• figure 2 shows a partially illustrated radiation therapy de ⁇ vice in accordance with a second alternative.
• the radiation therapy device in accordance with figures 1 and 2 comprises a radiation channel 2 that is designed as a tube and has a segment 4A, 4B of variable length.
• the segment 4A, 4B is fastened in each case between two sections of the ra ⁇ diation channel 2 via flanges 6.
• the front end of the radia ⁇ tion channel 2 is sealed with an exit window 8.
• the subregion orientated toward the exit window 8 forms a front region 10 of the radiation channel 2.
• This front region 10 is movably arranged in the longitudinal direction or direction of radia ⁇ tion 12 and supported on a support frame 16.
• a drive is pro ⁇ vided for the mobility of the front region 10 in the longitu- dinal direction 12.
• a drive motor 18 acts on the geared rack 20 that is permanently connected to a support ring 21 of the front region 10. Consequently, the geared rack 20, and thus the front region 10 can be displaced to and fro via the drive motor 18 in the longitudinal direction 12. Con ⁇ sequently, the geared rack 20, and thus the front region 10, can be displaced to and fro in the longitudinal direction 12 via the drive motor 18.
• the di ⁇ rection of radiation, and thus the longitudinal direction 12 runs in a horizontal direction. In a departure therefrom, it is also possible to provide directions of radiation deviating from the horizontal.
• a detector block 22 is fastened in a stationary fashion at the exit window 8 in front of the exit window 8.
• a particle detector and passive radiation elements are arranged, in a way not illustrated in more detail here, in the detector block 22.
• the radiation therapy device further comprises an imaging system that has a radiation source, in particular an X-ray radiation source 24, and an X-ray detector (not illustrated in more detail here) arranged opposite said X-ray radiation source.
• a radiation source in particular an X-ray radiation source 24, and an X-ray detector (not illustrated in more detail here) arranged opposite said X-ray radiation source.
• a patient 26 is arranged on a patient couch 28 in an immobilized fashion in the longitudinal direction 12 in front of the exit window 8.
• a target volume 30 to be irradiated is thereby aligned ex ⁇ actly in relation to a particle beam direction 12.
• This tar- get volume 30 is spaced from the exit window 8 in the direc ⁇ tion of radiation 14 by the spacing A.
• the patient 26 is firstly brought into the envisaged immobilized position such that the target volume 30 is fixed in a stationary fashion in the therapy space.
• the next step is to use the imaging system to carry out a positional verification.
• the exit window 8 is held in a retracted position such that the spacing A is as large as possible and, together with the detector block 22 arranged in front of the exit window 8 is of the order of magnitude of approximately 1 m or more in the exemplary em ⁇ bodiment.
• the spacing A is selected in this case in such a way as to enable the most optimum imaging possible, in order to attain high quality images.
• the exit window 8 is moved forward in the direction of the target volume 30 by an adjustment path S such that the exit window 8 is oriented as close as possible with the target volume 30.
• the front end of the detector block 22 is positioned virtually directly at the patient 26. The free path length between the exit window 8 and the target volume 30 is therefore minimized.
• the target volume 30 is then treated with a particle beam, for example a heavy ion beam.
• a particle beam for example a heavy ion beam.
• the particle beam is produced in this case in an accelerator (not illustrated in more detail here) and led through the radiation channel 2.
• An ultra high vacuum of typically approximately 10 ⁇ 8 mbar is set in the radiation channel 2 in order to prevent a beam expansion.
• the seg ⁇ ment 4A of variable length is designed as a corrugated hose or corrugated tube made from a sufficiently elastic material.
• the segment 4A is bounded at the ends by the flanges 6 with which it is sealed in a vacuum tight fashion at corresponding flanges of the radiation channel 2.
• the material of the seg- ment 4A in this way is of sufficient elasticity to enable the desired longitudinal displaceability and, simultaneously, to ensure the required sealing from the external surroundings.
• the radiation chan ⁇ nel 2 is firstly connected to the geared rack 20 via a front support ring 21 designed as a flange, and is also connected permanently to the support frame 16 via a rear support ring 21, likewise designed as a flange, so as to ensure a good me- chanical support for the entire radiation channel 2 in con ⁇ junction with mobility of the front region 10.
• the exemplary embodiment according to figure 2 differs from the exemplary embodiment according to figure 1 essentially by the fact that instead of the segment 4A designed in the man ⁇ ner of a corrugated tube, a section 4B of telescopic design is provided to the effect that the segment 4B has a reduced diameter, and that the segment 4B is arranged behind the rear support ring 21. Consequently, in this exemplary embodiment the front region is supported on the support frame 16 at two points via the support rings 21.
• the diameter Dl of the segment 4B in the region of the tele- scopic tube is approximately only 1/3 of the diameter D2 of the radiation channel 2 in the front region 10 near the exit window 8.
• the diameter D2 of the front region 10 is typically approximately 350 mm, the radiation channel 2 typically hav ⁇ ing in the region remote from the exit window 8 a diameter D2 in the range of approximately only 100 mm.
• the section 4B is arranged in this region of the radiation channel 2 remote from the exit window 8. Because of the reduced diameter, the increase in volume in the interior of the radiation channel 2 is kept slight in the event of a lengthening of the radiation channel 2. On the basis of the only slight increase in vol ⁇ ume, the pressure reduction, and thus also the force to be applied for the displacement of the target volume 30, is also kept slight.
• the variability in length described here for the radiation channel 2 enables all the components participating in the ra ⁇ diation to be used optimally such that, firstly, it is possi- ble to conduct imaging for localizing the target volume 30 as effectively and accurately as possible, and that, at the same time, it is ensured that the particle beam treats the target volume 30 in as precise and focused a manner as possible dur ⁇ ing the irradiation.
• the latter point is ensured by the re- duction in the spacing between the radiation channel 20 designed as a vacuum tube, and the target volume 30, that is to say the isocenter.

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• 2005
  • 2005-11-28 DE DE102005056698A patent/DE102005056698B4/de not_active Expired - Fee Related
• 2006
  • 2006-11-27 WO PCT/EP2006/068956 patent/WO2007060242A1/en active Application Filing

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