WO2017100611A1 - Système d'oncologie à rayonnement guidé par image auto-blindé - Google Patents

Système d'oncologie à rayonnement guidé par image auto-blindé Download PDF

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Publication number
WO2017100611A1
WO2017100611A1 PCT/US2016/065879 US2016065879W WO2017100611A1 WO 2017100611 A1 WO2017100611 A1 WO 2017100611A1 US 2016065879 W US2016065879 W US 2016065879W WO 2017100611 A1 WO2017100611 A1 WO 2017100611A1
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WIPO (PCT)
Prior art keywords
shielding
radiation
treatment
linac
patient
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Application number
PCT/US2016/065879
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English (en)
Inventor
Georg Weidlich
William L. Nighan
Dennis DORE
Original Assignee
ETM Electromatic, Inc.
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 ETM Electromatic, Inc. filed Critical ETM Electromatic, Inc.
Priority to US16/060,962 priority Critical patent/US10737122B2/en
Publication of WO2017100611A1 publication Critical patent/WO2017100611A1/fr
Priority to US16/989,858 priority patent/US20210162240A1/en

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Classifications

    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F7/00—Shielded cells or rooms
    • 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
    • A61N5/1048—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
    • 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
    • A61N2005/1063—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam maintaining the position when the patient is moved from an imaging to a therapy system
    • 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
    • A61N2005/1092—Details
    • A61N2005/1094—Shielding, protecting against radiation
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05G—X-RAY TECHNIQUE
    • H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
    • H05G1/02—Constructional details

Definitions

  • the present invention relates generally to radiation oncology
  • the present invention relates to radiotherapy systems which combine high resolution imagers, such as fan beam CT imagers, with linac-based X-ray systems.
  • 20MeV X-ray doses from linear accelerator systems are configured to provide dose rates that allow treatment of a cancer patient in term of "fractions", which refers to the dose in any given treatment session for a patient. For example, a dose rate of 10 Gy/minute at 1 meter from the linear accelerator is used for some 6MeV systems.
  • the most current linear accelerator systems such as those from Varian, Elekta, and Accuray generally include some form of X-ray imaging as part of the system, for the purpose of providing some form of image of a patient's tumor with respect to the patient's other anatomical structures.
  • a standard course of the diagnosis and development of a treatment plan for a cancer patient also includes developing patient images by high quality imaging machines in order to determine the size and position of a tumor or tumors to be treated with the X-ray dose. Imaging prior to radiation treatment can be performed with dedicated imaging systems such as fan-beam CT (computed
  • tomography scanners an MRI (magnetic resonance imaging) system, and/or a PET (positron emission tomography) scanner, with some PET scanners combining CT scanning within a single machine.
  • MRI magnetic resonance imaging
  • PET positron emission tomography
  • Each imaging technique has its advantages and provides benefits in creating images that are later used for treating cancer with high energy X-rays.
  • a further application of the fan-beam CT scanner is the ability to use a CT scan to correct for any inhomogeneity in a particular patient's tissues in order to optimize the radiation treatment plan.
  • a CT scan is used not only for the imaging of the tissue before treatment but also for correcting for tissue inhomogeneity in terms of Hounsfield units.
  • Radiation therapy systems generate multiple sources of unwanted radiation are produced that provide a threat to operators, workers in adjacent areas, and the public. These sources of radiation consist of primary radiation that is transmitted through the patient, scatter radiation produced by the patient tissues and parts of the Radiotherapy system that are exposed to the primary radiation, and leakage radiation from the X-ray generating and collimating components of the system.
  • Treatment rooms, or vaults or bunkers, used in radiation oncology include extensive shielding to protect medical personnel as well as the public from the radiation generated while treating the cancer patient.
  • Such shielding is most often made of concrete, although lead and steel and other materials can also be used when a smaller footprint is required or when limited by external dimensions.
  • a thickness of several feet of concrete shielding is typically used.
  • Such vaults typically cost at least $1 ,000,000, or $2,000,000 or more to shield a single multi-MeV level radiation oncology system and to finish the room to a standard that is suitable for treating patients.
  • IGRT image-guided radiotherapy
  • the present invention is self-shielded image-guided radiation
  • the present invention is self-shielding, thus substantially if not entirely eliminating the need for a vault or bunker to be constructed.
  • the system of the present invention can properly be described as a self-shielded, high quality image guided radiation therapy system, sometimes referred to hereinafter as an SS-HQIGRT system, although in other embodiments the invention may be thought of as comprising a self-shielded (sometimes "SS" hereinafter, for simplicity) linac-based X-ray source suitable for integration into an existing fan beam CT imaging system.
  • fan beam CT is employed in a radiation therapy machine for its greatly improved image quality for the day-of-treatment CT, thus offering the treating medical team much greater accuracy during the process of matching diagnostic CT images to day-of-treatment images, with a resulting improvement in the accuracy of treatment delivery.
  • the overall SS-HQIGRT system comprises a pre-existing fan beam CT scanner, already installed at the hospital or treatment center, and further comprises an SS X-ray source installed in line with that pre-existing fan beam CT.
  • the SS X-ray source is installed simultaneously with a fan beam CT scanner to provide a complete SS_HQIRT system.
  • the fan beam CT scanner may also be of the type used for simulation of radiation treatment.
  • the fan beam CT scanner rotates around the patient at high rpms while the radiation therapy portion - the X-ray source - operates, for example, at a rotation speed of 1 rpm or 6 degrees per second, which is fast enough for radiation treatment.
  • an energy level of 6MeV is sufficient for treatment of a large percentage of cancers.
  • the energy level of 6MeV also permits installation of the SS X-ray source without the need for a conventional vault or bunker. This permits the radiation therapy system of the present invention to be used at any hospital or facility that has or can install a fan beam CT scanner. Thus, many of the 27,000 facilities that have scanning capability can become full radiation therapy treatment centers.
  • the shielding material is
  • the X-ray source of the present invention comprises a "shielding ring" or “shielding arch” that blocks the entire primary radiation beam.
  • a beam stop is also used to attenuate the primary radiation beam.
  • a conventional vault or bunker, and the associated multi-million dollar expense, is not necessary.
  • additional secondary shielding is provided by the lead-lined Linac and radiation-defining head. In some instances, as additional facility shielding can be installed, such as removable lead or steel panels, if necessary or desired.
  • a primary shielding barrier covers all possible intercepts of the projected primary radiation field with the vault and therefore often requires a thickened "primary shielding belt" on the treatment room walls and the center portion of the ceiling.
  • the X-ray source is designed so that this primary shielding belt can be positioned closer to the patient with the result that the total area required shielding is greatly reduced.
  • An additional benefit provided by the use of a smaller radiation-source-to-isocenter distance than conventional linear accelerator systems is that the effective dose rate at the isocenter will increase. This permits a corresponding decrease in the utilization factor of the overall system, which in turn permits decreasing the required thickness of the primary shielding belt.
  • a radiation- source-to-isocenter distance of 85 centimeters can be used.
  • the size of the treatment field can be restricted to 25cm x 25cm at isocenter, which further decreases the required width of the primary shielding belt provided by the arch and/or beam stop.
  • the system of the present invention travels a substantially circular beam path which minimizes the area required to be covered by the primary shielding belt.
  • Figures 1 A and 1 B show in front elevation and side elevation views the overall design of an embodiment of an SSJHQIGRT system in
  • Figure 2 is a more detailed side elevational view of the embodiment shown in Figures 1A-1 B.
  • Figure 3 is a block diagram of the electrical system of an X-ray source in accordance with an embodiment of the invention.
  • Figure 4 is a block diagram illustrating the components of an
  • Figure 5 is a perspective view of a radiation therapy system in
  • Figure 6 is a perspective view of the system of Figure 5 showing the shielding arch and primary beam block of the X-ray source of the present invention relative to the couch of the CT scanner, where the couch is shared with both systems.
  • Figure 7 is a further perspective view of the system of Figure 5, with the radiation treatment head rotated for better viewing and with the primary beam block removed.
  • Figures 8A-8B show a perspective and front elevational view
  • Figure 9A shows in perspective view the embodiment of Figures 8A-8B separated from the CT scanner, thus showing the shielding cylinder in greater detail and with the linac and counterweight shown exposed for clarity.
  • Figure 9B shows in perspective view the embodiment of Figures
  • Figure 10 shows an exemplary arrangement of key components to facilitate a calculation of expected radiation leakage from the present invention such as shown in Figures 8A-8B.
  • FIG. 1 A-1 B and 2 an embodiment of an SS X- ray source 10 in accordance with the present invention can be better appreciated.
  • a linear accelerator, or linac, 100 moves around a ring gantry 105.
  • Shielding 1 10 can be incorporated around the ring gantry as shown in Figure 1A, or can be a separate arch 1 15 as shown in Figure 2.
  • the patient 120 is positioned on the CT support table, or couch, 125, and the CT imager 130 is positioned adjacent the SS X-ray source.
  • the Linac 100 is mounted isocentrically within the ring gantry 105 and is able to rotate almost a full rotation of 360 deg.
  • a multi-leaf collimator 135 is incorporated into the treatment head containing the linac 100. Further, in at least some embodiments, a beam stop 140 is positioned diametrically opposite the linac 100 and rotates with the linac to provide shielding.
  • the weight of the primary beam stop 140 is nearly the same weight as that of the shielded linac subassembly or treatment head 100, in order that the treatment head and the opposing primary beam stop balance one another when mounted upon the same rotating mechanism, such as a slew ring bearing mechanism [better seen in Figure 4].
  • the primary beam stop weighs approximately 5000 lbs and is substantially constructed of lead, and the shielded linac subassembly also weighs approximately 5000 lbs. Balancing the weights of these two main elements on the rotating structure reduces the amount of force required to maintain the linac orientation in any selected angle around the patient.
  • the gantry, treatment head and beam stop are designed to work with pre-existing CT scanner couches such that the SS X-ray source, or radiation therapy machine, of the present invention will share the couch with the CT scanner.
  • the treatment head containing the linac and multileaf collimator are configured to not interfere with movement of the CT scanner couch.
  • the treatment head of the SS-HQIGRT may only rotate through a portion of a 360 degree arc, in order to avoid interference with the CT scanner couch. This is not a severe limitation, and most cancers treatment plans use little or no angles of orientation of the treatment head below the patient.
  • a preferred embodiment of the invention features a treatment head that travels approximately 270 degrees around the patient, and the treatment head does not travel directly below the patient and couch.
  • the linac can rotate 270 degrees, from a starting angle of 225 degrees to a final angle of 135 degrees, although the direction of travel of travel is not important.
  • the ring gantry can permit movement of the treatment head and counter-balancing beam stop through the entire 360 degree arc.
  • the multileaf collimator (MLC) 135 allows a 25cm x 25cm maximum field size at the isocenter, and employs a single energy of 6MeV. Other field sizes and energies are possible, so long as the shielding is designed with these other parameters in mind. Higher energies and larger areas will generally require more shielding.
  • the source-to-axis distance can be approximately 85 cm.
  • MLC options are also acceptable, for example one that provides 10mm leaf size at the patient isocenter, or a "micro-MLC” that provides 3mm leaf size at the patient isocenter.
  • the 10mm MLC can be used for the majority of treatments, but the micro-MLC option is of interest as it can be used for treatments that benefit from a stereotactic radisosurgery approach (SRS) or a stereotactic body surgery approach (SBRS).
  • SRS stereotactic radisosurgery approach
  • SBRS stereotactic body surgery approach
  • Such treatments may include brain metastases, spine lesions, and lung and liver targets with stereotactic precision.
  • a common field size for the standard MLC may be 25cm x 25cm at the patient isocenter, whereas the field size for the micro-MLC option may be 10cm x 10cm, or another size.
  • the present invention is useful to handle overflow from a facility that has one or two high end systems that are at capacity yet where not all of the treated cases require the features of the high end radiation therapy machines.
  • the present invention permits adding an SS-HQIGRT system economically and with minimal facility impact, such that the high end machines can be reserved for cases that require the increased precision or energy levels that such machines offer.
  • the present invention also makes it possible to minimize the patient trauma that results from hospitalized patients that have to be transported to another facility for radiation therapy.
  • the present invention allows an effective radiation therapy system to be implemented at the local primary care facility such that these patients can be treated on site.
  • the SS X-ray source of the present invention attenuates the primary radiation with a solid arch 1 15 of lead shielding that will intercept the projection of the radiation beam of maximum useful field size for any available gantry angle.
  • the coverage of the arch can be matched to the amount of rotation possible.
  • arches 115 are shown with an opening therebetween since the linac of Figure 2 only rotates through 270 degrees.
  • the beam stop 140 is diametrically opposed to the radiation source downstream from the isocenter will attenuate the primary radiation further.
  • the combined thickness of the arch and beam stop is five Tenth-Value-Layers (TVL) equal to 28.5cm for 6MeV photon radiation, although the particular thickness can vary with the energy level of the radiation therapy source and shielding of, for example, 10 TVL can also be desirable for some embodiments.
  • the lead arch is floor-mounted with the inside surface of the arch having a constant distance to the isocenter of the SS-HQIGRT system.
  • the allowable Radiation level to the public is usually considered to be 100mrem/year (1 mSv/y) and 5,000mrem (50mSv/y) to radiation workers.
  • the overall shielding of the system i.e., integrated lead arch, head shielding and rotating beam stop, as well as steel plates in the wall of the SS-HQIGRT room, provide enough shielding that the escaping radiation levels that do not exceed these values.
  • VMAT Volumetrically Modulated Arc Therapy
  • a utilization factor of the system of 0.1 is assumed as a typical system will only deliver radiation for 10% of the time slot allotted for each patient.
  • a distance of 3.5m is assumed from the treatment isocenter to the nearest non-radiation worker in the adjacent offices. This will introduce an inverse-square correction factor of 0.081 . 5 TVL thickness will be assumed to be used for the primary shield.
  • the instantaneous exposure rate will be 300,000mrem/min which will be attenuated to
  • system also provides the mechanical benefit of providing a counterweight to the treatment head with its separate leakage shielding. It can be of benefit to nearly match the weight of the beam stop with the weight of treatment head, so that the two are balanced with respect to the mechanical load-bearing ring or gantry about which both rotate.
  • the balance of the rotating part of the system, with its two independent shields, can be of benefit for the purpose of precision location of the treatment beam, and can be of benefit in minimizing the mechanical power required to rotate and stabilize the machine.
  • an X-ray scanning system according to an embodiment of the invention is shown in block diagram form at 300.
  • external power and signals 305 are received by a control processor 310. Included among the external signals are, typically, one or more trigger signals indicating that the user desires to scan an object, for example a cargo container on a vehicle passing before the scanning system.
  • the control processor 310 controls, directly or indirectly, the operation of the remaining functional blocks shown in Figure 3 by virtue of signals sent on internal bus 315, which, for simplicity, is shown combined with internal power.
  • control processor 310 In response to the trigger signal(s), the control processor 310
  • the processor 305 sends, depending upon the implementation, a plurality of signals to initiate generation of an X-ray pulse.
  • the processor 305 sends control signals to a high voltage power supply 320 and an associated modulator 325 which receives the output from the supply 320.
  • the supply 320 can be, for example, a Lambda LC1202.
  • the output of the modulator 325 supplies a high voltage output to a pulse transformer 330, typically immersed in an insulating tank for purposes of electrical isolation.
  • An aspect of the modulator is that can vary the voltages from one pulse to the next, and can operate at pulse durations of 2.5 psec or less, to permit operation at 400 pulses per second.
  • the modulator may incorporate a pulse-forming network or PFN.
  • a heater power supply 335 is associated with the tank and supplies the magnetron 340 or other suitable RF power source.
  • the pulse transformer 330 supplies high energy pulses, for example 30-50 kV at 100-1 10 amps, to a magnetron 340 or other suitable RF power source.
  • One suitable magnetron is the e2V model MG5193, which has an output of 2.6 MW at the normal S band frequency of 2.998 GHz.
  • Another is the MG7095, also from e2V.
  • Still other similar magnetrons are available from NJRC. The specific magnetron frequency is controlled by a mechanical tuner 345.
  • the magnetron 340 outputs an RF power pulse, indicated at 350, at the frequency determined by the tuner 345.
  • the pulses received by the magnetron can be of different, pre-selected voltage and currents, thus causing the magnetron to output pulses of different, pre-selected RF powers, for example, pulses of 40 kV and 45 kV at 100 amps and 1 10 amps, respectively.
  • the different powers of the RF pulses also affect the frequency of the output pulse, again as explained in greater detail below.
  • the RF power pulses pass through an arc detector 355, an isolator 360, and then to a linear particle accelerator (sometimes "linac" hereinafter) 365.
  • Suitable isolators are available from Ferrite Incorporated.
  • Conventional S-band waveguide 357 is used between magnetron and linac.
  • the pulses received from the transformer 330 can be in the range of, for example, 35-50 kV.
  • the linac 365 which typically has an effective Q in the range of 2000- 4000, but in any event less than 5000, receives the RF pulse.
  • the tuner 345 is adjusted so that the RF pulses from magnetron 340 are within the resonance bandwidth of the linac 365.
  • the pulses from the magnetron are, in an embodiment, substantially in the range of 2.5 MW, or between 2.0 MW and 3.0 MW.
  • the control processor 310 sends a control pulse to the modulator 325, and it sends a synchronized control pulse to a dual mode electron gun driver block 370.
  • the timing of these control pulses may be individually optimized.
  • the dual mode electron gun driver block 370 drives an electron gun 375, the cathode of which is within the vacuum envelope of the linac 365.
  • the gun 375 can be a triode gun design.
  • the pulses of beam current from electron gun 375 launch electrons into the cavities of the linac.
  • the cathode voltage is substantially in the range of -10 to -20 kV. In an embodiment it is -20kV.
  • the electrons are accelerated by the linac to a desired energy level, typically in the range of two to ten or more MeV with, for at least some embodiments, a separation between the energy levels of approximately 1 MeV or more between sequential pulses in a rapidly pulsed ABABABAB pattern.
  • the pulses are directed toward a target 380, for example tungsten, which, when hit with the pulse of accelerated electrons, emits pulses of X- rays.
  • the RF pulses are, in an embodiment, somewhat longer in duration than the electron gun pulses, such that the RF pulses can be thought of as creating an envelope within which the beam current pulses occur.
  • the duration of the beam current is selected by the control system 310, or can be pre-set during manufacture.
  • an AFC circuit 385 detects forward and reflected power from the linac, using dual directional couplers 390, and in turn controls the tuner 345 to ensure a continuing match between the linac and the magnetron in a manner known to those skilled in the art.
  • ancillaries 395 connect to the arc detector 355 and an ion pump 393 that feeds the linac 365, both in a manner known to those skilled in the art.
  • a cooling system 397 cools portions of the system in a manner known in the art, for example, the modulator, the pulse transformer tank, the linac, the target, and the isolator, as indicated by the dashed line 399. Suitable cooling systems are available from OptiTemp, and can be chosen dependent upon temperature and cooling requirements of the linac system.
  • a linac X-ray source 400 is surrounded by linac shielding 405.
  • a beam shaping unit 410 such as a multi-leaf collimator, is provided at the exit aperture of the linac 400.
  • the linac and associated shielding travel along a slew ring bearing 415 of a ring gantry 420 which forms the electro-mechanical part of the positioning system, with the movement of the linac along the bearing track controlled by rotation and positioning subsystem 425 and control system 430.
  • the treatment head and beam stop can both be mounted on a rotating frame where the frame is supported by the slew ring bearing 415.
  • the frame is not shown in Figure 4, for clarity, but is shown at 530 in Figures 6 and 7. In some embodiments such an
  • the linac output aperture and beam shaping unit direct the beam toward a patient 435 positioned on a couch 440, typically provided by an adjacent CT scanner or similar device.
  • a primary beam stop 445 Positioned diametrically opposed to the linac 400 is a primary beam stop 445, which moves with the linac 400 as discussed above.
  • a housing 450 for the bearing track (shown better in Figures 5-7) typically creates an annulus 455 through which the couch passes during the treatment of the patient.
  • the shielding arch 460 is floor mounting and its upper portion is substantially circular to match the substantially circular rotation of the treatment head 100 and beam stop 445. Connections to power, cooling water, and a user interface are all provided in a manner known to those skilled in the art.
  • T B s which is the
  • a radiation therapy plan file is provided to the system operator in standardized format such as DICOM.
  • the radiation therapy plan file is typically provided by a conventional treatment planning system, i.e., PROWESS Puma, Philips Pinnacle, or CMS Monaco. This file is imported by the control computer of the MeV radiation oncology system, such as control system 310 of the present invention and the control computers of similar prior art devices.
  • control computer of the MeV radiation oncology system such as control system 310 of the present invention and the control computers of similar prior art devices.
  • gantry position collimator position
  • MLC leaf positions dose rate, total dose delivered, and gantry speed.
  • These parameters are used to drive the respective components of the radiation oncology system to the required position or value.
  • the change in parameters is continuous (constantly changing gantry position, collimator position, etc.)
  • the actual values for these parameters are typically measured by potentiometers, optical encoders, or other conventional means for position measurement.
  • Dose rate is typically measured by the signal from the dose chamber.
  • Gantry speed is calculated by the measured rate of change of the gantry, for example degrees traveled per unit time.
  • a real-time correction is typically implemented to compensate for this deviation. Typically, if this feedback loop and real-time correction can be completed in approximately 20ms, any deviation is deemed clinically acceptable. In the case of total dose, the radiation is interrupted or stopped when this dose has been reached, to avoid overexposing the patient.
  • the present invention when used to treat a patient, and is physically positioned adjacent to a fan beam CT scanner, the original DICOM Image data file can be compared against a fan beam CT scan that is taken before every treatment.
  • the radiation treatment plan is typically created from a diagnostic fan beam CT scan, and so comparing with the fan beam CT scan taken with the fan beam CT scanner adjacent the present invention, where the patient remains on the same couch for both the CT scan and the radiation treatment, provides the treatment team with a much higher quality correlation between the original treatment plan images and the images taken on the day of treatment. This permits more accurate and reliable positioning of the patient.
  • SS_HQIRT system in accordance with the invention can be appreciated. Further, the juxtaposition of the SS X-ray source described in Figures 1 -4 with a fan beam CT scanner or equivalent high quality imager can also be appreciated.
  • the patient table or couch 500 can be seen to be mounted so that it passes through an annulus of a high quality imager 505 such as a fan beam CT scanner. Adjacent to the imager 505 is an SS X-ray source 510 in accordance with the invention, with only the outer housing 515 of the arch shown in Figure 5.
  • the linac-based treatment head 520 and associated beam stop 525 can be seen in Figures 6 and 7.
  • the frame 530 upon which the treatment head and beam stop are mounted is also shown, with the frame riding on a slew ring bearing, shown at 415 in Figure 4, mounted in the supporting wall or housing 535.
  • FIG. 8A-8B and 9A-9B a further alternative embodiment can be better appreciated, in which the shielding arch of Figures 5 and 6 is replaced with a shielding cylinder 800, perhaps best appreciated from Figure 9A.
  • a linac-based treatment head 805 and opposing beamstop or beam block 810 are supported on the shielding cylinder 800, and the gantry assembly of the head, beamstop and cylinder are rotatably mounted on a supporting frame or wall 815 by means of a slew ring bearing
  • the shielding cylinder 800 can comprise, for example, steel shielding of approximately 3" thick, while the beam block 810 is, in an embodiment, lead and provides 10 TVL shielding.
  • a patient couch 820 for a CT scanner 825 preferably a fan beam CT scanner although not necessarily in all
  • a tunnel 830 in the cylinder 800 extends through a tunnel 830 in the cylinder 800 and continuing through the wall 815, in alignment with the corresponding tunnel in the CT scanner 825.
  • Appropriate housings enclose each of these
  • the tunnel 830 inside the housing is, in an exemplary embodiment, approximately 80 cm in diameter.
  • the fan beam CT scanner can be any of
  • the shielding cylinder 800 offers the benefit of being closer to the patient and thus making it more effective as a radiation shield for a given weight.
  • the purpose of the cylinder 800 is to capture radiation scattered from the patient and from the primary beam block, thereby protecting personnel operating the equipment or otherwise present. Such personnel are typically in the vicinity of the equipment but a reasonable distance away, with that distance determined at least in part by the Siemens Sensation, the GE Lightspeed, the Philips MX, or other fan beam CT scanner capable of 8 to16 or more slices.
  • the shielding cylinder 800 offers the benefit of being closer to the patient and thus making it more effective as a radiation shield for a given weight.
  • the purpose of the cylinder 800 is to capture radiation scattered from the patient and from the primary beam block, thereby protecting personnel operating the equipment or otherwise present. Such personnel are typically in the vicinity of the equipment but a reasonable distance away, with that distance determined at least in part by the
  • the shielding cylinder 800 of Figures 8A-8B together with the beam stop 810 combine to provide shielding of ten Tenth-Value-Layers although the amount of shielding can vary with the implementation.
  • the embodiment of Figures 8A-9B offers substantially vaultless image-guided radio therapy, thus significantly simplifying the installation of such treatment capabilities in hospitals or other facilities that do not have vaults of the type typically required of conventional treatment systems.
  • the value of the present invention to provide radiotherapy to patient populations without prior access cannot be underestimated.
  • the present invention can be retrofitted to an existing CT scanner without the need to construct a vault around the combined system.
  • the present invention can provide IGRT with 6MeV over a 25 cm field, with a 1 cm MLC.
  • the percent depth does at 10 cm over a 10x10 field can be in the range of 61 .5% + 1 %, with a maximum dose depth of approximately 1.5 cm + 0.1 cm, a beam flatness (with interlock associated) of 3.0% and a beam symmetry (again with interlock associated) of 2.0%.
  • the dose rate at iso can be approximately 3 Gy/min to 6 Gy/min with a maximum field size of 25 cm x 25 cm at iso, where the MLC leaf width is 10 mm and the maximum leaf speed is about 3.0 cm/sec.
  • Such a system can have an isocenter positioning accuracy of approximately 1.0 mm with a maximum gantry speed of 6 degrees per second and a gantry positioning accuracy of 0.1 degrees.
  • the system can deliver either IGRT or VMAT, at a source to axis distance (SAD) of about 85 cm, during circular motion of the linac.
  • SAD source to axis distance
  • the rotation of the linac typically extends through 270 degrees, with the sector below the couch excluded from the rotation range in at least some embodiments.
  • leakage radiation can be approximately 0.005% of the exposure rate at the isocenter.
  • Figure 10 shows an arrangement of the present invention suitable for determining anticipated radiation exposure to the operator and others in the vicinity with a treatment room having 3" steel shielding at selected strategic locations. In most implementations such shielding will not be needed for the entire room, and the specific locations requiring such extra shielding can be determined upon implementation of the particular IGRT or VMAT system.
  • the anticipated radiation along the longitudinal (patient) axis at 2.8 meters from the isocenter, without shielding, is 145 mR/hr, but with properly located three inch steel shielding drops to 3.6 mR/hr.
  • the present invention avoids the need to construct the conventional vault of several feet of concrete, or extensive lead shielding.
  • the present invention offers significantly improved performance and usability in that it enables facilities that previously could not accommodate IGRT to offer treatment to patients requiring such medical treatments.

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  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Pathology (AREA)
  • High Energy & Nuclear Physics (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Radiology & Medical Imaging (AREA)
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  • General Health & Medical Sciences (AREA)
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  • Veterinary Medicine (AREA)
  • Radiation-Therapy Devices (AREA)

Abstract

La présente invention concerne un système de radiothérapie guidée par image adapté pour être juxtaposé de façon adjacente à un scanner TDM qui comprend un cadre ayant un orifice adapté pour permettre le passage à travers celui-ci d'un lit sur lequel un patient est positionné, conjointement avec un ensemble de portique monté de façon rotative sur le cadre dans lequel l'ensemble de portique comprend un cylindre de blindage comportant un orifice à travers celui-ci aligné avec l'orifice dans le cadre. Le cylindre de blindage comporte, fixée à celui-ci, une tête de traitement à base de LINAC configurée pour effectuer une radiothérapie, et un arrêt de faisceau positionné de façon angulaire en position opposée à la tête de traitement pour absorber le rayonnement provenant de la tête de traitement. Le cylindre de blindage assure un blindage suffisant du rayonnement diffusé depuis le patient et le reste du système ne nécessite pas une voûte conventionnelle. Dans certains modes de réalisation, un arc peut être utilisé à la place d'un cylindre.
PCT/US2016/065879 2014-02-27 2016-12-09 Système d'oncologie à rayonnement guidé par image auto-blindé WO2017100611A1 (fr)

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US16/989,858 US20210162240A1 (en) 2014-02-27 2020-08-10 Self-shielded image guided radiation oncology system

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US62/265,130 2015-12-09

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WO2019050551A1 (fr) * 2017-09-06 2019-03-14 Zap Surgical Systems, Inc. Système de radiochirurgie à commande intégrée autoprotégé
CN109646819A (zh) * 2018-12-29 2019-04-19 佛山瑞加图医疗科技有限公司 一种加速器偏摆支架
US10499861B2 (en) 2017-09-06 2019-12-10 Zap Surgical Systems, Inc. Self-shielded, integrated-control radiosurgery system
US11058892B2 (en) 2017-05-05 2021-07-13 Zap Surgical Systems, Inc. Revolving radiation collimator
US20210283425A1 (en) * 2018-11-30 2021-09-16 Auracare Co., Ltd. Radiography and radiotherapy apparatus
US11684446B2 (en) 2019-02-27 2023-06-27 Zap Surgical Systems, Inc. Device for radiosurgical treatment of uterine fibroids

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Cited By (8)

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Publication number Priority date Publication date Assignee Title
US11058892B2 (en) 2017-05-05 2021-07-13 Zap Surgical Systems, Inc. Revolving radiation collimator
US11826582B2 (en) 2017-05-05 2023-11-28 Zap Surgical Systems, Inc. Revolving radiation collimator
WO2019050551A1 (fr) * 2017-09-06 2019-03-14 Zap Surgical Systems, Inc. Système de radiochirurgie à commande intégrée autoprotégé
US10499861B2 (en) 2017-09-06 2019-12-10 Zap Surgical Systems, Inc. Self-shielded, integrated-control radiosurgery system
US11844637B2 (en) 2017-09-06 2023-12-19 Zap Surgical Systems, Inc. Therapeutic radiation beam detector for radiation treatment systems
US20210283425A1 (en) * 2018-11-30 2021-09-16 Auracare Co., Ltd. Radiography and radiotherapy apparatus
CN109646819A (zh) * 2018-12-29 2019-04-19 佛山瑞加图医疗科技有限公司 一种加速器偏摆支架
US11684446B2 (en) 2019-02-27 2023-06-27 Zap Surgical Systems, Inc. Device for radiosurgical treatment of uterine fibroids

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