# Patent

## Title
Multi-field charged particle cancer therapy method and apparatus

## Abstract

The invention relates generally to treatment of solid cancers. More particularly, the invention relates to a multi-field charged particle cancer therapy method and apparatus coordinated with negative ion beam creation, ion beam focusing, charged particle acceleration, patient rotation, and/or patient respiration. Preferably, the charged particle therapy is performed on a patient in a partially immobilized and repositionable position. Proton delivery is preferably timed to patient respiration via control of charged particle beam injection, acceleration, and/or targeting methods and apparatus.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to PCT Patent Application No. PCT/RU2009/000105 filed 4 Mar. 2009.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to treatment of solid cancers. More particularly, the invention relates to a multi-field charged particle cancer therapy system optionally used in combination with beam injection, acceleration, extraction, respiration, and/or targeting methods and apparatus.
2. Discussion of the Prior Art
Cancer
A tumor is an abnormal mass of tissue. Tumors are either benign or malignant. A benign tumor grows locally, but does not spread to other parts of the body. Benign tumors cause problems because of their spread, as they press and displace normal tissues. Benign tumors are dangerous in confined places such as the skull. A malignant tumor is capable of invading other regions of the body. Metastasis is cancer spreading by invading normal tissue and spreading to distant tissues.
Cancer Treatment
Several forms of radiation therapy exist for cancer treatment including: brachytherapy, traditional electromagnetic X-ray therapy, and proton therapy. Each are further described, infra.
Brachytherapy is radiation therapy using radioactive sources implanted inside the body. In this treatment, an oncologist implants radioactive material directly into the tumor or very close to it. Radioactive sources are also placed within body cavities, such as the uterine cervix.
The second form of traditional cancer treatment using electromagnetic radiation includes treatment using X-rays and gamma rays. An X-ray is high-energy, ionizing, electromagnetic radiation that is used at low doses to diagnose disease or at high doses to treat cancer. An X-ray or Röntgen ray is a form of electromagnetic radiation with a wavelength in the range of 10 to 0.01 nanometers (nm), corresponding to frequencies in the range of 30 PHz to 30 EHz. X-rays are longer than gamma rays and shorter than ultraviolet rays. X-rays are primarily used for diagnostic radiography. X-rays are a form of ionizing radiation and can be dangerous. Gamma rays are also a form of electromagnetic radiation and are at frequencies produced by sub-atomic particle interactions, such as electron-positron annihilation or radioactive decay. In the electromagnetic spectrum, gamma rays are generally characterized as electromagnetic radiation having the highest frequency, as having highest energy, and having the shortest wavelength, such as below about 10 picometers. Gamma rays consist of high energy photons with energies above about 100 keV. X-rays are commonly used to treat cancerous tumors. However, X-rays are not optimal for treatment of cancerous tissue as X-rays deposit their highest dose of radiation near the surface of the targeted tissue and delivery exponentially less radiation as they penetrate into the tissue. This results in large amounts of radiation being delivered outside of the tumor. Gamma rays have similar limitations.
The third form of cancer treatment uses protons. Proton therapy systems typically include: a beam generator, an accelerator, and a beam transport system to move the resulting accelerated protons to a plurality of treatment rooms where the protons are delivered to a tumor in a patient's body.
Proton therapy works by aiming energetic ionizing particles, such as protons accelerated with a particle accelerator, onto a target tumor. These particles damage the DNA of cells, ultimately causing their death. Cancerous cells, because of their high rate of division and their reduced ability to repair damaged DNA, are particularly vulnerable to attack on their DNA.
Due to their relatively enormous size, protons scatter less easily than X-rays or gamma rays in the tissue and there is very little lateral dispersion. Hence, the proton beam stays focused on the tumor shape without much lateral damage to surrounding tissue. All protons of a given energy have a certain range, defined by the Bragg peak, and the dosage delivery to tissue ratio is maximum over just the last few millimeters of the particle's range. The penetration depth depends on the energy of the particles, which is directly related to the speed to which the particles were accelerated by the proton accelerator. The speed of the proton is adjustable to the maximum rating of the accelerator. It is therefore possible to focus the cell damage due to the proton beam at the very depth in the tissues where the tumor is situated. Tissues situated before the Bragg peak receive some reduced dose and tissues situated after the peak receive none.
Synchrotron
Patents related to the current invention are summarized here.
Proton Beam Therapy System
F. Cole, et. al. of Loma Linda University Medical Center “Multi-Station Proton Beam Therapy System”, U.S. Pat. No. 4,870,287 (Sep. 26, 1989) describe a proton beam therapy system for selectively generating and transporting proton beams from a single proton source and accelerator to a selected treatment room of a plurality of patient treatment rooms.
Beam Formation
C. Johnstone, “Method and Apparatus for Laser Controlled Proton Beam Radiology”, U.S. Pat. No. 5,760,395 (Jun. 2, 1998) describes a proton beam radiology system having an accelerator producing an H− beam and a laser. The laser and H− beam are combined to form a neutral beam. A photodetachment module further uses a stripping foil, which forms a proton beam from the neutral beam.
T. Ikeguchi, et. al. “Synchrotron Radiation Source With Beam Stabilizers”, U.S. Pat. No. 5,177,448 (Jan. 5, 1993) describe a synchrotron radiation source having, for the purpose of prolonging lifetime of a charged particle beam, beam absorbers made of a material having a low photodesorption yield that are disposed inside a bending section/vacuum chamber.
Injection
K. Hiramoto, et. al. “Accelerator System”, U.S. Pat. No. 4,870,287 (Sep. 26, 1989) describes an accelerator system having a selector electromagnet for introducing an ion beam accelerated by pre-accelerators into either a radioisotope producing unit or a synchrotron.
K. Hiramoto, et. al. “Circular Accelerator, Method of Injection of Charged Particle Thereof, and Apparatus for Injection of Charged Particle Thereof”, U.S. Pat. No. 5,789,875 (Aug. 4, 1998) and K. Hiramoto, et. al. “Circular Accelerator, Method of Injection of Charged Particle Thereof, and Apparatus for Injection of Charged Particle Thereof”, U.S. Pat. No. 5,600,213 (Feb. 4, 1997) both describe a method and apparatus for injecting a large number of charged particles into a vacuum duct where the beam of injection has a height and width relative to a geometrical center of the duct.
Accelerator/Synchrotron
H. Tanaka, et. al. “Charged Particle Accelerator”, U.S. Pat. No. 7,259,529 (Aug. 21, 2007) describe a charged particle accelerator having a two period acceleration process with a fixed magnetic field applied in the first period and a timed second acceleration period to provide compact and high power acceleration of the charged particles.
T. Haberer, et. al. “Ion Beam Therapy System and a Method for Operating the System”, U.S. Pat. No. 6,683,318 (Jan. 27, 2004) describe an ion beam therapy system and method for operating the system. The ion beam system uses a gantry that has a vertical deflection system and a horizontal deflection system positioned before a last bending magnet that result in a parallel scanning mode resulting from an edge focusing effect.
V. Kulish, et. al. “Inductional Undulative EH-Accelerator”, U.S. Pat. No. 6,433,494 (Aug. 13, 2002) describe an inductive undulative EH-accelerator for acceleration of beams of charged particles. The device consists of an electromagnet undulation system, whose driving system for electromagnets is made in the form of a radio-frequency (RF) oscillator operating in the frequency range from about 100 KHz to 10 GHz.
K. Saito, et. al. “Radio-Frequency Accelerating System and Ring Type Accelerator Provided with the Same”, U.S. Pat. No. 5,917,293 (Jun. 29, 1999) describe a radio-frequency accelerating system having a loop antenna coupled to a magnetic core group and impedance adjusting means connected to the loop antenna. A relatively low voltage is applied to the impedance adjusting means allowing small construction of the adjusting means.
J. Hirota, et. al. “Ion Beam Accelerating Device Having Separately Excited Magnetic Cores”, U.S. Pat. No. 5,661,366 (Aug. 26, 1997) describe an ion beam accelerating device having a plurality of high frequency magnetic field inducing units and magnetic cores.
J. Hirota, et. al. “Acceleration Device for Charged Particles”, U.S. Pat. No. 5,168,241 (Dec. 1, 1992) describe an acceleration cavity having a high frequency power source and a looped conductor operating under a control that combine to control a coupling constant and/or de-tuning allowing transmission of power more efficiently to the particles.
Vacuum Chamber
T. Kobari, et. al. “Apparatus For Treating the Inner Surface of Vacuum Chamber”, U.S. Pat. No. 5,820,320 (Oct. 13, 1998) and T. Kobari, et. al. “Process and Apparatus for Treating Inner Surface Treatment of Chamber and Vacuum Chamber”, U.S. Pat. No. 5,626,682 (May 6, 1997) both describe an apparatus for treating an inner surface of a vacuum chamber including means for supplying an inert gas or nitrogen to a surface of the vacuum chamber with a broach. Alternatively, the broach is used for supplying a lower alcohol to the vacuum chamber for dissolving contaminants on the surface of the vacuum chamber.
Magnet Shape
M. Tadokoro, et. al. “Electromagnetic and Magnetic Field Generating Apparatus”, U.S. Pat. No. 6,365,894 (Apr. 2, 2002) and M. Tadokoro, et. al. “Electromagnetic and Magnetic Field Generating Apparatus”, U.S. Pat. No. 6,236,043 (May 22, 2001) each describe a pair of magnetic poles, a return yoke, and exciting coils. The interior of the magnetic poles each have a plurality of air gap spacers to increase magnetic field strength.
Extraction
T. Nakanishi, et. al. “Charged-Particle Beam Accelerator, Particle Beam Radiation Therapy System Using the Charged-Particle Beam Accelerator, and Method of Operating the Particle Beam Radiation Therapy System”, U.S. Pat. No. 7,122,978 (Oct. 17, 2006) describe a charged particle beam accelerator having an RF-KO unit for increasing amplitude of betatron oscillation of a charged particle beam within a stable region of resonance and an extraction quadrupole electromagnet unit for varying a stable region of resonance. The RF-KO unit is operated within a frequency range in which the circulating beam does not go beyond a boundary of stable region of resonance and the extraction quadrupole electromagnet is operated with timing required for beam extraction.
T. Haberer, et. al. “Method and Device for Controlling a Beam Extraction Raster Scan Irradiation Device for Heavy Ions or Protons”, U.S. Pat. No. 7,091,478 (Aug. 15, 2006) describe a method for controlling beam extraction irradiation in terms of beam energy, beam focusing, and beam intensity for every accelerator cycle.
K. Hiramoto, et. al. “Accelerator and Medical System and Operating Method of the Same”, U.S. Pat. No. 6,472,834 (Oct. 29, 2002) describe a cyclic type accelerator having a deflection electromagnet and four-pole electromagnets for making a charged particle beam circulate, a multi-pole electromagnet for generating a stability limit of resonance of betatron oscillation, and a high frequency source for applying a high frequency electromagnetic field to the beam to move the beam to the outside of the stability limit. The high frequency source generates a sum signal of a plurality of alternating current (AC) signals of which the instantaneous frequencies change with respect to time, and of which the average values of the instantaneous frequencies with respect to time are different. The system applies the sum signal via electrodes to the beam.
K. Hiramoto, et. al. “Synchrotron Type Accelerator and Medical Treatment System Employing the Same”, U.S. Pat. No. 6,087,670 (Jul. 11, 2000) and K. Hiramoto, et. al. “Synchrotron Type Accelerator and Medical Treatment System Employing the Same”, U.S. Pat. No. 6,008,499 (Dec. 28, 1999) describe a synchrotron accelerator having a high frequency applying unit arranged on a circulating orbit for applying a high frequency electromagnetic field to a charged particle beam circulating and for increasing amplitude of betatron oscillation of the particle beam to a level above a stability limit of resonance. Additionally, for beam ejection, four-pole divergence electromagnets are arranged: (1) downstream with respect to a first deflector; (2) upstream with respect to a deflecting electromagnet; (3) downstream with respect to the deflecting electromagnet; and (4) and upstream with respect to a second deflector.
K. Hiramoto, et. al. “Circular Accelerator and Method and Apparatus for Extracting Charged-Particle Beam in Circular Accelerator”, U.S. Pat. No. 5,363,008 (Nov. 8, 1994) describe a circular accelerator for extracting a charged-particle beam that is arranged to: (1) increase displacement of a beam by the effect of betatron oscillation resonance; (2) to increase the betatron oscillation amplitude of the particles, which have an initial betatron oscillation within a stability limit for resonance; and (3) to exceed the resonance stability limit thereby extracting the particles exceeding the stability limit of the resonance.
K. Hiramoto, et. al. “Method of Extracting Charged Particles from Accelerator, and Accelerator Capable Carrying Out the Method, by Shifting Particle Orbit”, U.S. Pat. No. 5,285,166 (Feb. 8, 1994) describe a method of extracting a charged particle beam. An equilibrium orbit of charged particles maintained by a bending magnet and magnets having multipole components greater than sextuple components is shifted by a constituent element of the accelerator other than these magnets to change the tune of the charged particles.
Transport/Scanning Control
K. Matsuda, et. al. “Particle Beam Irradiation Apparatus, Treatment Planning Unit, and Particle Beam Irradiation Method”, U.S. Pat. No. 7,227,161 (Jun. 5, 2007); K. Matsuda, et. al. “Particle Beam Irradiation Treatment Planning Unit, and Particle Beam Irradiation Method”, U.S. Pat. No. 7,122,811 (Oct. 17, 2006); and K. Matsuda, et. al. “Particle Beam Irradiation Apparatus, Treatment Planning Unit, and Particle Beam Irradiation Method” (Sep. 5, 2006) each describe a particle beam irradiation apparatus have a scanning controller that stops output of an ion beam, changes irradiation position via control of scanning electromagnets, and reinitiates treatment based on treatment planning information.
T. Norimine, et. al. “Particle Therapy System Apparatus”, U.S. Pat. No. 7,060,997 (Jun. 13, 2006); T. Norimine, et. al. “Particle Therapy System Apparatus”, U.S. Pat. No. 6,936,832 (Aug. 30, 2005); and T. Norimine, et. al. “Particle Therapy System Apparatus”, U.S. Pat. No. 6,774,383 (Aug. 10, 2004) each describe a particle therapy system having a first steering magnet and a second steering magnet disposed in a charged particle beam path after a synchrotron that are controlled by first and second beam position monitors.
K. Moriyama, et. al. “Particle Beam Therapy System”, U.S. Pat. No. 7,012,267 (Mar. 14, 2006) describe a manual input to a ready signal indicating preparations are completed for transport of the ion beam to a patient.
H. Harada, et. al. “Irradiation Apparatus and Irradiation Method”, U.S. Pat. No. 6,984,835 (Jan. 10, 2006) describe an irradiation method having a large irradiation field capable of uniform dose distribution, without strengthening performance of an irradiation field device, using a position controller having overlapping area formed by a plurality of irradiations via use of a multileaf collimator. The system provides flat and uniform dose distribution over an entire surface of a target.
H. Akiyama, et. al. “Charged Particle Beam Irradiation Equipment Having Scanning Electromagnet Power Supplies”, U.S. Pat. No. 6,903,351 (Jun. 7, 2005); H. Akiyama, et. al. “Charged Particle Beam Irradiation Equipment Having Scanning Electromagnet Power Supplies”, U.S. Pat. No. 6,900,436 (May 31, 2005); and H. Akiyama, et. al. “Charged Particle Beam Irradiation Equipment Having Scanning Electromagnet Power Supplies”, U.S. Pat. No. 6,881,970 (Apr. 19, 2005) all describe a power supply for applying a voltage to a scanning electromagnet for deflecting a charged particle beam and a second power supply without a pulsating component to control the scanning electromagnet more precisely allowing for uniform irradiation of the irradiation object.
K. Amemiya, et. al. “Accelerator System and Medical Accelerator Facility”, U.S. Pat. No. 6,800,866 (Oct. 5, 2004) describe an accelerator system having a wide ion beam control current range capable of operating with low power consumption and having a long maintenance interval.
A. Dolinskii, et. al. “Gantry with an Ion-Optical System”, U.S. Pat. No. 6,476,403 (Nov. 5, 2002) describe a gantry for an ion-optical system comprising an ion source and three bending magnets for deflecting an ion beam about an axis of rotation. A plurality of quadrupoles are also provided along the beam path to create a fully achromatic beam transport and an ion beam with different emittances in the horizontal and vertical planes. Further, two scanning magnets are provided between the second and third bending magnets to direct the beam.
H. Akiyama, et. al. “Charged Particle Beam Irradiation Apparatus”, U.S. Pat. No. 6,218,675 (Apr. 17, 2001) describe a charged particle beam irradiation apparatus for irradiating a target with a charged particle beam that includes a plurality of scanning electromagnets and a quadrupole electromagnet between two of the plurality of scanning electromagnets.
K. Matsuda, et. al. “Charged Particle Beam Irradiation System and Method Thereof”, U.S. Pat. No. 6,087,672 (Jul. 11, 2000) describe a charged particle beam irradiation system having a ridge filter with shielding elements to shield a part of the charged particle beam in an area corresponding to a thin region in the target.
P. Young, et. al. “Raster Scan Control System for a Charged-Particle Beam”, U.S. Pat. No. 5,017,789 (May 21, 1991) describe a raster scan control system for use with a charged-particle beam delivery system that includes a nozzle through which a charged particle beam passes. The nozzle includes a programmable raster generator and both fast and slow sweep scan electromagnets that cooperate to generate a sweeping magnetic field that steers the beam along a desired raster scan pattern at a target.
Beam Shape Control
M. Yanagisawa, et. al. “Particle Beam Irradiation System and Method of Adjusting Irradiation Field Forming Apparatus”, U.S. Pat. No. 7,154,107 (Dec. 26, 2006) and M. Yanagisawa, et. al. “Particle Beam Irradiation System and Method of Adjusting Irradiation Field Forming Apparatus”, U.S. Pat. No. 7,049,613 (May 23, 2006) each describe a particle therapy system having a scattering compensator and a range modulation wheel. Movement of the scattering compensator and the range modulation wheel adjusts a size of the ion beam and scattering intensity resulting in penumbra control and a more uniform dose distribution to a diseased body part.
T. Haberer, et. al. “Device and Method for Adapting the Size of an Ion Beam Spot in the Domain of Tumor Irradiation”, U.S. Pat. No. 6,859,741 (Feb. 22, 2005) describe a method and apparatus for adapting the size of an ion beam in tumor irradiation. Quadrupole magnets determining the size of the ion beam spot are arranged directly in front of raster scanning magnets determining the size of the ion beam spot. The apparatus contains a control loop for obtaining current correction values to further control the ion beam spot size.
K. Matsuda, et. al. “Charged Particle Irradiation Apparatus and an Operating Method Thereof”, U.S. Pat. No. 5,986,274 (Nov. 16, 1999) describe a charged particle irradiation apparatus capable of decreasing a lateral dose falloff at boundaries of an irradiation field of a charged particle beam using controlling magnet fields of quadrupole electromagnets and deflection electromagnets to control the center of the charged particle beam passing through the center of a scatterer irrespective of direction and intensity of a magnetic field generated by scanning electromagnets.
K. Hiramoto, et. al. “Charged Particle Beam Apparatus and Method for Operating the Same”, U.S. Pat. No. 5,969,367 (Oct. 19, 1999) describe a charged particle beam apparatus where the charged particle beam is enlarged by a scatterer resulting in a Gaussian distribution that allows overlapping of irradiation doses applied to varying spot positions.
M. Moyers, et. al. “Charged Particle Beam Scattering System”, U.S. Pat. No. 5,440,133 (Aug. 8, 1995) describe a radiation treatment apparatus for producing a particle beam and a scattering foil for changing the diameter of the charged particle beam.
C. Nunan “Multileaf Collimator for Radiotherapy Machines”, U.S. Pat. No. 4,868,844 (Sep. 19, 1989) describes a radiation therapy machine having a multileaf collimator formed of a plurality of heavy metal leaf bars movable to form a rectangular irradiation field.
R. Maughan, et. al. “Variable Radiation Collimator”, U.S. Pat. No. 4,754,147 (Jun. 28, 1988) describe a variable collimator for shaping a cross-section of a radiation beam that relies on rods, which are positioned around a beam axis. The rods are shaped by a shaping member cut to a shape of an area of a patient to be irradiated.
Treatment Room Selection
J. Naumann, et. al. “Beam Allocation Apparatus and Beam Allocation Method for Medical Particle Accelerators”, U.S. Pat. No. 7,351,988 (Apr. 1, 2008) describe a beam allocation apparatus for medical particle accelerators having an arbitration unit, switching logic, a monitoring unit, and sequence control with a safety spill abort system.
K. Moriyama, et. al. “Particle Beam Therapy System”, U.S. Pat. No. 7,319,231 (Jan. 15, 2008) describe a beam server system to a plurality of treatment rooms with irradiation ready signals allowing first-come, first-served control of the treatment beam.
K. Moriyama, et. al. “Particle Beam Therapy System”, U.S. Pat. No. 7,262,424 (Aug. 28, 2007) describe a particle beam therapy system that uses information from treatment rooms to control delivery of the ion beam to one of a plurality of treatment rooms.
I. Morgan, et. al. “Multiple Target, Multiple Energy Radioisotope Production”, U.S. Pat. No. 6,444,990 (Sep. 3, 2002) describe a particle beam transport path having an inlet path and multiple kicker magnets, where turning a given kicker magnet on results in the particle beam being directed to a corresponding room.
M. Takanaka, et. al. “Beam Supply Device”, U.S. Pat. No. 5,349,198 (Sep. 20, 1994) describe a beam supply device for supplying a particle or radiation beam to a therapy room, where the system includes a rotatable beam transportation device and a plurality of beam utilization rooms disposed around a rotational axis of the rotatable deflection electromagnet.
Beam Energy/Intensity
M. Yanagisawa, et. al. “Charged Particle Therapy System, Range Modulation Wheel Device, and Method of Installing Range Modulation Wheel Device”, U.S. Pat. No. 7,355,189 (Apr. 8, 2008) and Yanagisawa, et. al. “Charged Particle Therapy System, Range Modulation Wheel Device, and Method of Installing Range Modulation Wheel Device”, U.S. Pat. No. 7,053,389 (May 30, 2008) both describe a particle therapy system having a range modulation wheel. The ion beam passes through the range modulation wheel resulting in a plurality of energy levels corresponding to a plurality of stepped thicknesses of the range modulation wheel.
M. Yanagisawa, et. al. “Particle Beam Irradiation System and Method of Adjusting Irradiation Apparatus”, U.S. Pat. No. 7,297,967 (Nov. 20, 2007); M. Yanagisawa, et. al. “Particle Beam Irradiation System and Method of Adjusting Irradiation Apparatus”, U.S. Pat. No. 7,071,479 (Jul. 4, 2006); M. Yanagisawa, et. al. “Particle Beam Irradiation System and Method of Adjusting Irradiation Apparatus”, U.S. Pat. No. 7,026,636 (Apr. 11, 2006); and M. Yanagisawa, et. al. “Particle Beam Irradiation System and Method of Adjusting Irradiation Apparatus”, U.S. Pat. No. 6,777,700 (Aug. 17, 2004) all describe a scattering device, a range adjustment device, and a peak spreading device. The scattering device and range adjustment device are combined together and are moved along a beam axis. The spreading device is independently moved along the axis to adjust the degree of ion beam scattering. Combined, the device increases the degree of uniformity of radiation dose distribution to a diseased tissue.
A. Sliski, et. al. “Programmable Particle Scatterer for Radiation Therapy Beam Formation”, U.S. Pat. No. 7,208,748 (Apr. 24, 2007) describe a programmable pathlength of a fluid disposed into a particle beam to modulate scattering angle and beam range in a predetermined manner. The charged particle beam scatterer/range modulator comprises a fluid reservoir having opposing walls in a particle beam path and a drive to adjust the distance between the walls of the fluid reservoir under control of a programmable controller to create a predetermined spread out Bragg peak at a predetermined depth in a tissue. The beam scattering and modulation is continuously and dynamically adjusted during treatment of a tumor to deposit a dose in a targeted predetermined three dimensional volume.
M. Tadokoro, et. al. “Particle Therapy System”, U.S. Pat. No. 7,247,869 (Jul. 24, 2007) and U.S. Pat. No. 7,154,108 (Dec. 26, 2006) each describe a particle therapy system capable of measuring energy of a charged particle beam during irradiation of cancerous tissue. The system includes a beam passage between a pair of collimators, an energy detector, and a signal processing unit.
G. Kraft, et. al. “Ion Beam Scanner System and Operating Method”, U.S. Pat. No. 6,891,177 (May 10, 2005) describe an ion beam scanning system having a mechanical alignment system for the target volume to be scanned allowing for depth modulation of the ion beam by means of a linear motor and transverse displacement of energy absorption means resulting in depth-staggered scanning of volume elements of a target volume.
G. Hartmann, et. al. “Method for Operating an Ion Beam Therapy System by Monitoring the Distribution of the Radiation Dose”, U.S. Pat. No. 6,736,831 (May 18, 2004) describe a method for operation of an ion beam therapy system having a grid scanner that irradiates and scans an area surrounding an isocentre. Both the depth dose distribution and the transverse dose distribution of the grid scanner device at various positions in the region of the isocentre are measured and evaluated.
Y. Jongen “Method for Treating a Target Volume with a Particle Beam and Device Implementing Same”, U.S. Pat. No. 6,717,162 (Apr. 6, 2004) describes a method of producing from a particle beam a narrow spot directed toward a target volume, characterized in that the spot sweeping speed and particle beam intensity are simultaneously varied.
G. Kraft, et. al. “Device for Irradiating a Tumor Tissue”, U.S. Pat. No. 6,710,362 (Mar. 23, 2004) describe a method and apparatus of irradiating a tumor tissue, where the apparatus has an electromagnetically driven ion-braking device in the proton beam path for depth-wise adaptation of the proton beam that adjusts both the ion beam direction and ion beam range.
K. Matsuda, et. al. “Charged Particle Beam Irradiation Apparatus”, U.S. Pat. No. 6,617,598 (Sep. 9, 2003) describe a charged particle beam irradiation apparatus that increases the width in a depth direction of a Bragg peak by passing the Bragg peak through an enlarging device containing three ion beam components having different energies produced according to the difference between passed positions of each of the filter elements.
H. Stelzer, et. al. “Ionization Chamber for Ion Beams and Method for Monitoring the Intensity of an Ion Beam”, U.S. Pat. No. 6,437,513 (Aug. 20, 2002) describe an ionization chamber for ion beams and a method of monitoring the intensity of an ion therapy beam. The ionization chamber includes a chamber housing, a beam inlet window, a beam outlet window and a chamber volume filled with counting gas.
H. Akiyama, et. al. “Charged-Particle Beam Irradiation Method and System”, U.S. Pat. No. 6,433,349 (Aug. 13, 2002) and H. Akiyama, et. al. “Charged-Particle Beam Irradiation Method and System”, U.S. Pat. No. 6,265,837 (Jul. 24, 2001) both describe a charged particle beam irradiation system that includes a changer for changing energy of the particle and an intensity controller for controlling an intensity of the charged-particle beam.
Y. Pu “Charged Particle Beam Irradiation Apparatus and Method of Irradiation with Charged Particle Beam”, U.S. Pat. No. 6,034,377 (Mar. 7, 2000) describes a charged particle beam irradiation apparatus having an energy degrader comprising: (1) a cylindrical member having a length; and (2) a distribution of wall thickness in a circumferential direction around an axis of rotation, where thickness of the wall determines energy degradation of the irradiation beam.
Dosage
K. Matsuda, et. al. “Particle Beam Irradiation System”, U.S. Pat. No. 7,372,053 (Nov. 27, 2007) describe a particle beam irradiation system ensuring a more uniform dose distribution at an irradiation object through use of a stop signal, which stops the output of the ion beam from the irradiation device.
H. Sakamoto, et. al. “Radiation Treatment Plan Making System and Method”, U.S. Pat. No. 7,054,801 (May 30, 2006) describe a radiation exposure system that divides an exposure region into a plurality of exposure regions and uses a radiation simulation to plan radiation treatment conditions to obtain flat radiation exposure to the desired region.
G. Hartmann, et. al. “Method For Verifying the Calculated Radiation Dose of an Ion Beam Therapy System”, U.S. Pat. No. 6,799,068 (Sep. 28, 2004) describe a method for the verification of the calculated dose of an ion beam therapy system that comprises a phantom and a discrepancy between the calculated radiation dose and the phantom.
H. Brand, et. al. “Method for Monitoring the Irradiation Control of an Ion Beam Therapy System”, U.S. Pat. No. 6,614,038 (Sep. 2, 2003) describe a method of checking a calculated irradiation control unit of an ion beam therapy system, where scan data sets, control computer parameters, measuring sensor parameters, and desired current values of scanner magnets are permanently stored.
T. Kan, et. al. “Water Phantom Type Dose Distribution Determining Apparatus”, U.S. Pat. No. 6,207,952 (Mar. 27, 2001) describe a water phantom type dose distribution apparatus that includes a closed water tank, filled with water to the brim, having an inserted sensor that is used to determine an actual dose distribution of radiation prior to radiation therapy.
Safety
K. Moriyama, et. al. “Particle Beam Therapy System”, U.S. Pat. No. 7,345,292 (Mar. 18, 2008) describe a safety device confirming that preparations for generation of an ion beam in an accelerator are completed and preparations for transport of the ion beam in a beam transport system are completed. A ready state display unit for displaying the ready information is additionally provided.
C. Cheng, et. al. “Path Planning and Collision Avoidance for Movement of Instruments in a Radiation Therapy Environment”, U.S. Pat. No. 7,280,633 (Oct. 9, 2007) describe a patient positioning system that includes external measurement devices, which measure the location and orientation of objects, including components of the radiation therapy system. The positioning system also monitors for intrusion into the active area of the therapy system by personnel or foreign objects to improve operational safety of the radiation therapy system.
K. Moriyama, et. al. “Particle Beam Therapy System”, U.S. Pat. No. 7,173,264 (Feb. 6, 2007) describe a particle beam therapy system having a group of shutters to prevent erroneous downstream irradiation of a non-elected treatment room.
E. Badura, et. al. “Method for Checking Beam Generation and Beam Acceleration Means of an Ion Beam Therapy System”, U.S. Pat. No. 6,745,072 (Jun. 1, 2004) describe a method of checking beam generation means and beam acceleration means of an ion beam therapy system, where the type of ion, the ion beam energy, the ion beam intensity, the blocking of the accelerator, and means for terminating extraction are checked.
E. Badura, et. al. “Method for Checking Beam Steering in an Ion Beam Therapy System”, U.S. Pat. No. 6,639,234 (Oct. 28, 2003), describe a method of checking beam guidance of an ion beam therapy system, where redundant means are used for: (1) termination of extraction; and (2) verification of termination.
E. Badura, et. al. “Method of Operating an Ion Beam Therapy System with Monitoring of Beam Position”, U.S. Pat. No. 6,600,164 (Jul. 29, 2003) describe a method for the operation of an ion beam therapy system that includes a beam scanner device directing a beam to an isocentre, where the region of the isocentre is monitored and evaluated with intervention being carried out upon a departure from a tolerance value based on a half-value width of the beam profile.
E. Badura, et. al. “Method for Monitoring an Emergency Switch-Off of an Ion-Beam Therapy System”, U.S. Pat. No. 6,597,005 (Jul. 22, 2003) describe a method of checking emergency shutdown of an ion beam therapy system.
B. Britton, et. al. “Beamline Control and Security System for a Radiation Treatment Facility”, U.S. Pat. No. 5,895,926 (Apr. 20, 1999) describe a method and apparatus for beamline security in radiation beam treatment facilities. Upon detection of an error, beamline power supplies are disabled.
T. Nakanishi, et. al. “Particle Beam Irradiation Apparatus”, U.S. Pat. No. 5,818,058 (Oct. 6, 1998) describe a particle beam irradiation field having shields, for shielding radiation, placed symmetrically with respect to a radiation axis.
B. Britton, et. al. “Beamline Control and Security System for a Radiation Treatment Facility”, U.S. Pat. No. 5,585,642 (Dec. 17, 1996) describe a method and apparatus for beamline security in radiation beam treatment facilities that compares beam path configuration signals corresponding to a requested beam configuration using complimentary redundant logical communication paths. Upon detection of an error, beamline power supplies are disabled.
D. Lesyna, et. al. “Method of Treatment Room Selection Verification in a Radiation Beam Therapy System”, U.S. Pat. No. 5,260,581 (Nov. 9, 1993) describe a method of treatment room selection verification in a radiation beam therapy system that compares treatment room request signals with a beam path configuration signal from a switchyard that controls the path of beam travel from an accelerator to a treatment room.
Calibration
V. Bashkirov, et. al. “Nanodosimeter Based on Single Ion Detection”, U.S. Pat. No. 7,081,619 (Jul. 25, 2006) and V. Bashkirov, et. al. “Nanodosimeter Based on Single Ion Detection”, U.S. Pat. No. 6,787,771 (Sep. 7, 2004) both describe a nanodosimeter device for detecting positive ions that pass through an aperture opening, pass through a sensitive gas volume, and arrive at a detector. The invention includes use of the nanodosimeter for calibrating radiation exposure to damage to a nucleic acid within a sample.
G. Hartmann, et. al. “Method of Checking an Isocentre and a Patient-Positioning Device of an Ion Beam Therapy System”, U.S. Pat. No. 6,670,618 (Dec. 30, 2003) describe a method of checking an isocentre of an ion beam using a grid scanner device and a spherical phantom. On departure of a spatial center point from a predetermined threshold, the ion beam system is subjected to maintenance.
M. Wofford, et. al. “System and Method for Automatic Calibration of a Multileaf Collimator”, U.S. Pat. No. 6,322,249 (Nov. 27, 2001) describe a system and method for calibrating a radiation therapy device by moving a leaf of a collimator, determining whether a distance between the leaf and a line approximately equals a predetermined measurement, and associating the predetermined measurement with a collimator specific count.
D. Legg, et. al. “Normalizing and Calibrating Therapeutic Radiation Delivery Systems”, U.S. Pat. No. 5,511,549 (Apr. 30, 1996), describe a method for normalization and dose calibration of a radiation therapy delivery system. The advantages are particularly significant for proton therapy facilities containing a plurality of delivery systems. The method permits a prescribed treatment to be administered with accuracy not only at the station associated with the initial treatment planning, but at any available delivery station.
Starting/Stopping Irradiation
K. Hiramoto, et. al. “Charged Particle Beam Apparatus and Method for Operating the Same”, U.S. Pat. No. 6,316,776 (Nov. 13, 2001) describe a charged particle beam apparatus where a charged particle beam is positioned, started, stopped, and repositioned repetitively. Residual particles are used in the accelerator without supplying new particles if sufficient charge is available.
K. Matsuda, et. al. “Method and Apparatus for Controlling Circular Accelerator”, U.S. Pat. No. 6,462,490 (Oct. 8, 2002) describe a control method and apparatus for a circular accelerator for adjusting timing of emitted charged particles. The clock pulse is suspended after delivery of a charged particle stream and is resumed on the basis of state of an object to be irradiated.
Gantry
T. Yamashita, et. al. “Rotating Irradiation Apparatus”, U.S. Pat. No. 7,381,979 (Jun. 3, 2008) describe a rotating gantry having a front ring and a rear ring, each ring having radial support devices, where the radial support devices have linear guides. The system has thrust support devices for limiting movement of the rotatable body in the direction of the rotational axis of the rotatable body.
T. Yamashita, et. al. “Rotating Gantry of Particle Beam Therapy System” U.S. Pat. No. 7,372,053 (May 13, 2008) describe a rotating gantry supported by an air braking system allowing quick movement, braking, and stopping of the gantry during irradiation treatment.
M. Yanagisawa, et. al. “Medical Charged Particle Irradiation Apparatus”, U.S. Pat. No. 6,992,312 (Jan. 31, 2006); M. Yanagisawa, et. al. “Medical Charged Particle Irradiation Apparatus”, U.S. Pat. No. 6,979,832 (Dec. 27, 2005); and M. Yanagisawa, et. al. “Medical Charged Particle Irradiation Apparatus”, U.S. Pat. No. 6,953,943 (Oct. 11, 2005) all describe an apparatus capable of irradiation from upward and horizontal directions. The gantry is rotatable about an axis of rotation where the irradiation field forming device is eccentrically arranged, such that an axis of irradiation passes through a different position than the axis of rotation.
H. Kaercher, et. al. “Isokinetic Gantry Arrangement for the Isocentric Guidance of a Particle Beam And a Method for Constructing Same”, U.S. Pat. No. 6,897,451 (May 24, 2005) describe an isokinetic gantry arrangement for isocentric guidance of a particle beam that can be rotated around a horizontal longitudinal axis.
G. Kraft, et. al. “Ion Beam System for Irradiating Tumor Tissues”, U.S. Pat. No. 6,730,921 (May 4, 2004) describe an ion beam system for irradiating tumor tissues at various irradiation angles in relation to a horizontally arranged patient couch, where the patient couch is rotatable about a center axis and has a lifting mechanism. The system has a central ion beam deflection of up to ±15 degrees with respect to a horizontal direction.
M. Pavlovic, et. al. “Gantry System and Method for Operating Same”, U.S. Pat. No. 6,635,882 (Oct. 21, 2003) describe a gantry system for adjusting and aligning an ion beam onto a target from a freely determinable effective treatment angle. The ion beam is aligned on a target at adjustable angles of from 0 to 360 degrees around the gantry rotation axis and at an angle of 45 to 90 degrees off of the gantry rotation axis yielding a cone of irradiation when rotated a full revolution about the gantry rotation axis.
Detector
E. Berdermann, et. al. “Detector for Detecting Particle Beams and Method for the Production Thereof”, U.S. Pat. No. 7,274,025 (Sep. 25, 2007) describe a detector and a method of making the detector. The detector comprises a crystalline semi-conductor diamond plate and a aluminum metal coating arranged on a ceramic plate substrate.
Movable Patient
N. Rigney, et. al. “Patient Alignment System with External Measurement and Object Coordination for Radiation Therapy System”, U.S. Pat. No. 7,199,382 (Apr. 3, 2007) describe a patient alignment system for a radiation therapy system that includes multiple external measurement devices that obtain position measurements of movable components of the radiation therapy system. The alignment system uses the external measurements to provide corrective positioning feedback to more precisely register the patient to the radiation beam.
Y. Muramatsu, et. al. “Medical Particle Irradiation Apparatus”, U.S. Pat. No. 7,030,396 (Apr. 18, 2006); Y. Muramatsu, et. al. “Medical Particle Irradiation Apparatus”, U.S. Pat. No. 6,903,356 (Jun. 7, 2005); and Y. Muramatsu, et. al. “Medical Particle Irradiation Apparatus”, U.S. Pat. No. 6,803,591 (Oct. 12, 2004) all describe a medical particle irradiation apparatus having a rotating gantry, an annular frame located within the gantry such that it can rotate relative to the rotating gantry, an anti-correlation mechanism to keep the frame from rotating with the gantry, and a flexible moving floor engaged with the frame in such a manner to move freely with a substantially level bottom while the gantry rotates.
H. Nonaka, et. al. “Rotating Radiation Chamber for Radiation Therapy”, U.S. Pat. No. 5,993,373 (Nov. 30, 1999) describe a horizontal movable floor composed of a series of multiple plates that are connected in a free and flexible manner, where the movable floor is moved in synchrony with rotation of a radiation beam irradiation section.
Respiration
K. Matsuda “Radioactive Beam Irradiation Method and Apparatus Taking Movement of the Irradiation Area Into Consideration”, U.S. Pat. No. 5,538,494 (Jul. 23, 1996) describes a method and apparatus that enables irradiation even in the case of a diseased part changing position due to physical activity, such as breathing and heart beat. Initially, a position change of a diseased body part and physical activity of the patient are measured concurrently and a relationship therebetween is defined as a function. Radiation therapy is performed in accordance to the function.
Patient Positioning
Y. Nagamine, et. al. “Patient Positioning Device and Patient Positioning Method”, U.S. Pat. No. 7,212,609 (May 1, 2007) and Y. Nagamine, et. al. “Patient Positioning Device and Patient Positioning Method”, U.S. Pat. No. 7,212,608 (May 1, 2007) describe a patient positioning system that compares a comparison area of a reference X-ray image and a current X-ray image of a current patient location using pattern matching.
D. Miller, et. al. “Modular Patient Support System”, U.S. Pat. No. 7,173,265 (Feb. 6, 2007) describe a radiation treatment system having a patient support system that includes a modularly expandable patient pod and at least one immobilization device, such as a moldable foam cradle.
K. Kato, et. al. “Multi-Leaf Collimator and Medical System Including Accelerator”, U.S. Pat. No. 6,931,100 (Aug. 16, 2005); K. Kato, et. al. “Multi-Leaf Collimator and Medical System Including Accelerator”, U.S. Pat. No. 6,823,045 (Nov. 23, 2004); K. Kato, et. al. “Multi-Leaf Collimator and Medical System Including Accelerator”, U.S. Pat. No. 6,819,743 (Nov. 16, 2004); and K. Kato, et. al. “Multi-Leaf Collimator and Medical System Including Accelerator”, U.S. Pat. No. 6,792,078 (Sep. 14, 2004) all describe a system of leaf plates used to shorten positioning time of a patient for irradiation therapy. Motor driving force is transmitted to a plurality of leaf plates at the same time through a pinion gear. The system also uses upper and lower air cylinders and upper and lower guides to position a patient.
Computer Control
A. Beloussov et. al. “Configuration Management and Retrieval System for Proton Beam Therapy System”, U.S. Pat. No. 7,368,740 (May 6, 2008); A. Beloussov et. al. “Configuration Management and Retrieval System for Proton Beam Therapy System”, U.S. Pat. No. 7,084,410 (Aug. 1, 2006); and A. Beloussov et. al. “Configuration Management and Retrieval System for Proton Beam Therapy System”, U.S. Pat. No. 6,822,244 (Nov. 23, 2004) all describe a multi-processor software controlled proton beam system having treatment configurable parameters that are easily modified by an authorized user to prepare the software controlled system for various modes of operation to insure that data and configuration parameters are accessible if single point failures occur in the database.
J. Hirota et. al. “Automatically Operated Accelerator Using Obtained Operating Patterns”, U.S. Pat. No. 5,698,954 (Dec. 16, 1997) describes a main controller for determining the quantity of control and the control timing of every component of an accelerator body with the controls coming from an operating pattern.
Imaging
P. Adamee, et. al. “Charged Particle Beam Apparatus and Method for Operating the Same”, U.S. Pat. No. 7,274,018 (Sep. 25, 2007) and P. Adamee, et. al. “Charged Particle Beam Apparatus and Method for Operating the Same”, U.S. Pat. No. 7,045,781 (May 16, 2006) describe a charged particle beam apparatus configured for serial and/or parallel imaging of an object.
K. Hiramoto, et. al. “Ion Beam Therapy System and its Couch Positioning System”, U.S. Pat. No. 7,193,227 (Mar. 20, 2007) describe an ion beam therapy system having an X-ray imaging system moving in conjunction with a rotating gantry.
C. Maurer, et. al. “Apparatus and Method for Registration of Images to Physical Space Using a Weighted Combination of Points and Surfaces”, U.S. Pat. No. 6,560,354 (May 6, 2003) described a process of X-ray computed tomography registered to physical measurements taken on the patient's body, where different body parts are given different weights. Weights are used in an iterative registration process to determine a rigid body transformation process, where the transformation function is used to assist surgical or stereotactic procedures.
M. Blair, et. al. “Proton Beam Digital Imaging System”, U.S. Pat. No. 5,825,845 (Oct. 20, 1998) describe a proton beam digital imaging system having an X-ray source that is movable into the treatment beam line that can produce an X-ray beam through a region of the body. By comparison of the relative positions of the center of the beam in the patient orientation image and the isocentre in the master prescription image with respect to selected monuments, the amount and direction of movement of the patient to make the best beam center correspond to the target isocentre is determined.
S. Nishihara, et. al. “Therapeutic Apparatus”, U.S. Pat. No. 5,039,867 (Aug. 13, 1991) describe a method and apparatus for positioning a therapeutic beam in which a first distance is determined on the basis of a first image, a second distance is determined on the basis of a second image, and the patient is moved to a therapy beam irradiation position on the basis of the first and second distances.
Proton and Neutron Therapy/Particle Selection
L. Dahl, et. al. “Apparatus for Generating and Selecting Ions used in a Heavy Ion Cancer Therapy Facility”, U.S. Pat. No. 6,809,325 (Oct. 26, 2004) describe an apparatus for generating, extracting, and selecting ions used in a heavy ion cancer therapy facility including a cyclotron resonance ion source for generating heavy and light ions and selection means for selecting heavy ion species of one isotopic configuration downstream of each ion source.
J. Slater, et. al. “System and Method for Multiple Particle Therapy”, U.S. Pat. No. 5,866,912 (Feb. 2, 1999) describe a proton beam therapy system, where protons pass through a beryllium neutron source generating a source of protons and neutrons.
Problem
There exists in the art of a need for accurate and precise delivery of irradiation energy to a tumor. More particularly, there exists a need to efficiently generate a negative ion beam, focus the ion beam, convert the ion beam into a charged particle beam, acceleration the charged particle beam, immobilize and/or reproducibly position a person relative to a particle therapy beam, and/or target the charged particle beam to a tumor.
SUMMARY OF THE INVENTION
The invention comprises a method and apparatus for treatment of solid cancers. In one embodiment, the invention relates to a multi-field charged particle cancer therapy method and apparatus coordinated with negative ion beam creation, ion beam focusing, charged particle acceleration, patient rotation, and/or patient respiration. Preferably, the charged particle therapy is performed on a patient in a partially immobilized and repositionable position. Proton delivery is preferably timed to patient respiration via control of charged particle beam injection, acceleration, and/or targeting methods and apparatus.



DESCRIPTION OF THE FIGURES
FIG. 1 illustrates component connections of a charged particle beam therapy system;
FIG. 2 illustrates a charged particle therapy system;
FIG. 3 illustrates an ion beam generation system;
FIG. 4 illustrates a negative ion beam source;
FIG. 5 illustrates an ion beam focusing system;
FIGS. 6 A-D illustrate focusing electrodes about a negative ion beam path;
FIG. 7A illustrates a negative ion beam path vacuum system; FIG. 7B illustrates a support structure; FIG. 7C illustrates a foil;
FIG. 8 is a particle beam therapy control flowchart;
FIG. 9 illustrates straight and turning sections of a synchrotron
FIG. 10 illustrates bending magnets of a synchrotron;
FIG. 11 provides a perspective view of a bending magnet;
FIG. 12 illustrates a cross-sectional view of a bending magnet;
FIG. 13 illustrates a cross-sectional view of a bending magnet;
FIG. 14A illustrates a RF accelerator and FIG. 14B illustrate RF accelerator subsystem;
FIG. 15 illustrates a magnetic field control system;
FIG. 16 illustrates a patient positioning system from: (A) a front view and (B) a top view;
FIG. 17 provides X-ray and proton beam dose distributions;
FIGS. 18 A-E illustrate controlled scanning and depth of focus irradiation;
FIGS. 19 A-E illustrate multi-field irradiation;
FIG. 20 illustrates dose efficiency enhancement via use of multi-field irradiation;
FIG. 21 provides two methods of multi-field irradiation implementation;
FIG. 22 illustrates a semi-vertical patient positioning system;
FIG. 23 provides an example of a sitting patient positioning system;
FIG. 24 illustrates a laying patient positioning system;
FIG. 25 illustrates a head restraint system;
FIG. 26 illustrates hand and head supports;



DETAILED DESCRIPTION OF THE INVENTION
The invention relates generally to treatment of solid cancers.
In one embodiment, a charged particle beam cancer therapy system is used to treat a solid tumor of a patient.
In another embodiment, the invention relates to a multi-field charged particle cancer therapy method and apparatus.
In yet another embodiment, a patient positioning method and apparatus is used in conjunction with a cancer treating multi-axis charged particle beam or proton beam radiation therapy method and apparatus. The patient positioning system is used to translate the patient and/or rotate the patient into a zone where the proton beam can scan the tumor using a targeting system. The patient positioning system is optionally used in conjunction with systems used to constrain movement of the patient, such as semi-vertical, sitting, or laying positioning systems.
In still yet another embodiment, a charged particle beam acceleration and extraction method and apparatus is used in conjunction with charged particle beam radiation therapy of cancerous tumors. Particularly, novel synchrotron turning magnets are used to minimize the overall size of the synchrotron, provide a tightly controlled proton beam, directly reduce the size of required magnetic fields, directly reduce required operating power, and allow continual acceleration of protons in a synchrotron even during a process of extracting protons from the synchrotron.
In another embodiment, a charged particle cancer therapy system is described having a combined rotation/raster method and apparatus, referred to as multi-field charged particle cancer therapy. The system uses a fixed orientation proton source relative to a rotating patient to yield tumor irradiation from multiple directions. The system combines layer-wise tumor irradiation from many directions with controlled energy proton irradiation to deliver peak proton beam energy within a selected tumor volume or irradiated slice. Optionally, the selected tumor volume for irradiation from a given angle is a distal portion of the tumor. In this manner ingress Bragg peak energy is circumferentially spread about the tumor minimizing damage to healthy tissue and peak proton energy is efficiently, accurately, and precisely delivered to the tumor.
In still yet another embodiment, using a charged particle cancer therapy system, a method and apparatus for efficient radiation dose delivery to a tumor is described. Radiation is delivered through an entry point into the tumor and Bragg peak energy is targeted to a distal or far side of the tumor from an ingress point. Delivering Bragg peak energy to the distal side of the tumor from the ingress point is repeated from multiple rotational directions. The multi-field irradiation process with energy levels targeting the far side of the tumor from each irradiation direction provides even and efficient charged particle radiation dose delivery to the tumor. Preferably, the charged particle therapy is timed to patient respiration via control of charged particle beam injection, acceleration, extraction, and/or targeting methods and apparatus.
In yet another embodiment, a semi-vertical patient positioning, alignment, and/or control method and apparatus is used in conjunction with charged particle, or proton beam, radiation therapy of cancerous tumors. Patient positioning constraints are used to maintain the patient in a treatment position, including one or more of: a seat support, a back support, a head support, an arm support, a knee support, and a foot support. One or more of the positioning constraints are movable and/or under computer control for rapid positioning and/or immobilization of the patient. The system optionally uses an X-ray beam that lies in substantially the same path as a proton beam path of a particle beam cancer therapy system. The generated image is usable for: fine tuning body alignment relative to the proton beam path, to control the proton beam path to accurately and precisely target the tumor, and/or in system verification and validation.
In a further embodiment, a semi-vertical or seated patient positioning, alignment, and/or control method and apparatus is used in conjunction with multi-axis charged particle, or proton beam, radiation therapy of cancerous tumors. Patient positioning constraints are used to maintain the patient in a treatment position. The patient positioning constraints include one or more of: a seat support, a back support, a head support, an arm support, a knee support, and a foot support. One or more of the positioning constraints are movable and/or under computer control for rapid positioning and/or immobilization of the patient.
In another embodiment, a patient respiration or breath monitoring and/or control method and apparatus is used in conjunction with multi-axis charged particle, or proton beam, radiation therapy of cancerous tumors. The respiration monitoring system uses thermal and/or force sensors to determine where a patient is in a breathing cycle in combination with a feedback signal control delivered to the patient to inform the patient when breath control is required. The resulting breath control is timed with charged particle delivery to the tumor to enhance accuracy, precision, and/or efficiency of tumor treatment.
In yet another embodiment relates generally to treatment of solid cancers. More particularly, a computer controlled patient positioning, immobilization, and repositioning method and apparatus is used in conjunction with multi-field charged particle cancer therapy coordinated with patient respiration patterns and further in combination with charged particle beam injection, acceleration, extraction, and/or targeting methods and apparatus.
In still another embodiment, a negative ion source method and apparatus is used as part of an ion beam injection system, which is used in conjunction with multi-axis charged particle or proton beam radiation therapy of cancerous tumors. The negative ion source preferably includes an inlet port for injection of hydrogen gas into a high temperature plasma chamber. In one case, the plasma chamber includes a magnetic material, which provides a magnetic field barrier between the high temperature plasma chamber and a low temperature plasma region on the opposite side of the magnetic field barrier. An extraction pulse is applied to a negative ion extraction electrode to pull the negative ion beam into a negative ion beam path, which proceeds through a first partial vacuum system, through an ion beam focusing system, into the tandem accelerator, and into a synchrotron.
In still yet another embodiment, a negative ion beam source vacuum method and apparatus is used as part of an ion beam injection system, which is used in conjunction with multi-axis charged particle or proton beam radiation therapy of cancerous tumors. The negative ion beam source contains a vacuum chamber isolated by a vacuum barrier from the vacuum tube of the synchrotron. The negative ion beam source vacuum system preferably includes: a first pump turbo molecular pump, a large holding volume, and a semi-continuously operating pump. By only pumping the ion beam source vacuum chamber and by only semi-continuously operating the ion beam source vacuum based on sensor readings in or about the holding volume, the lifetime of the semi-continuously operating pump is extended.
In yet still another embodiment, an ion beam focusing method and apparatus is used as part of an ion beam injection system, which is used in conjunction with multi-axis charged particle or proton beam radiation therapy of cancerous tumors. The ion beam focusing system includes two or more electrodes where one electrode of each electrode pair partially obstructs the ion beam path with conductive paths, such as a conductive mesh. In a given electrode pair, electric field lines, running between the conductive mesh of a first electrode and a second electrode, provide inward forces focusing the negative ion beam. Multiple such electrode pairs provide multiple negative ion beam focusing regions.
The another embodiment, a tandem accelerator method and apparatus, which is part of an ion beam injection system, is used in conjunction with multi-axis charged particle radiation therapy of cancerous tumors. The negative ion beam source preferably includes an injection system vacuum system and a synchrotron vacuum system separated by a foil, where negative ions are converted to positive ions. The foil is preferably directly or indirectly sealed to the edges of the vacuum tube providing for a higher partial pressure in the injection system vacuum chamber and a lower pressure in the synchrotron vacuum system. Having the foil physically separating the vacuum chamber into two pressure regions allows for fewer and/or smaller pumps to maintain the lower pressure system in the synchrotron as the inlet hydrogen gas is extracted in a separate contained and isolated space by the injection partial vacuum system.
In yet another embodiment, a radio-frequency (RF) accelerator method and apparatus is used in conjunction with multi-axis charged particle radiation therapy of cancerous tumors. An RF synthesizer provides a low voltage RF signal, that is synchronized to the period of circulation of protons in the proton beam path, to a set of integrated microcircuits, loops, and coils where the coils circumferentially enclose the proton beam path in a synchrotron. The integrated components combine to provide an accelerating voltage to the protons in the proton beam path in a size compressed and price reduced format. The integrated RF-amplifier microcircuit/accelerating coil system is operable from about 1 MHz, for a low energy proton beam, to about 15 MHz, for a high energy proton beam.
In still yet another embodiment, a multi-field imaging and a multi-field charged particle cancer therapy method and apparatus is coordinated with patient respiration via use of feedback sensors used to monitor and/or control patient respiration.
Used in combination with any embodiment of the invention, one or more of novel design features of a charged particle beam cancer therapy system are described. Particularly, a negative ion beam source with novel features in the negative ion source, ion source vacuum system, ion beam focusing lens, and tandem accelerator is described. Additionally, the synchrotron includes: turning magnets and edge focusing magnets, which minimize the overall size of the synchrotron, provide a tightly controlled proton beam, directly reduce the size of required magnetic fields, directly reduces required operating power. The ion beam source system and synchrotron are preferably computer integrated with a patient imaging system and a patient interface including breath monitoring sensors and patient positioning elements. Further, the system is integrated with acceleration and/or targeting method and apparatus. More particularly, energy and timing control of a charged particle stream of a synchrotron is coordinated with patient positioning and tumor treatment. The synchrotron control elements allow tight control of the charged particle beam, which compliments the tight control of patient positioning to yield efficient treatment of a solid tumor with reduced tissue damage to surrounding healthy tissue. In addition, the system reduces the overall size of the synchrotron, provides a tightly controlled proton beam, directly reduces the size of required magnetic fields, directly reduces required operating power, and allows continual acceleration of protons in a synchrotron even during a process of extracting protons from the synchrotron. Combined, the systems provide for efficient, accurate, and precise noninvasive tumor treatment with minimal damage to surrounding healthy tissue.
In various embodiments, the charged particle cancer therapy system incorporates any of:

    
    
        an injection system having a central magnetic member and a magnetic field separating high and low temperature plasma regions;
        a dual vacuum system creating a first partial pressure region on a plasma generation system side of a foil in a tandem accelerator and a second lower partial pressure region on the synchrotron side of the foil;
        a negative ion beam focusing system having a conductive mesh axially crossing the negative ion beam;
        a synchrotron having four straight sections and four turning sections;
        a synchrotron having no hexapole magnets;
        four bending magnets in each turning section of the synchrotron;
        a winding coil wrapping multiple bending magnets;
        a plurality of bending magnets that are beveled and charged particle focusing in each turning section;
        integrated RF-amplifier microcircuits providing currents through loops about accelerating coils;
        a rotatable platform for turning the subject allowing multi-field imaging and/or multi-field proton therapy;
        a radiation plan dispersing ingress Bragg peak energy 360 degrees about the tumor;
        positioning, immobilizing, and repositioning systems;
        respiratory sensors;
        simultaneous and independent control of:
        
            proton beam energy
            x-axis proton beam control;
            y-axis proton beam control;
            patient translation; and
            patient rotation; and
        
        
        a system timing charged particle therapy to one or more of:
        
            patient translation;
            patient rotation; and
            patient breathing.

Proton Therapy

        
        
    
    


Due to their relatively enormous size, protons scatter less easily than X-rays or gamma rays in the tissue and there is very little lateral dispersion. Hence, the proton beam stays focused on the tumor shape without much lateral damage to surrounding tissue. All protons of a given energy have a certain range, defined by the Bragg peak, and the dosage delivery to tissue ratio is maximum over just the last few millimeters of the particle's range. The penetration depth depends on the energy of the particles, which is directly related to the speed to which the particles were accelerated by the proton accelerator. The speed of the proton is adjustable to the maximum rating of the accelerator. It is therefore possible to focus the cell damage due to the proton beam at the very depth in the tissues where the tumor is situated. Tissues situated before the Bragg peak receive some reduced dose and tissues situated after the peak receive none.
Cyclotron/Synchrotron
A cyclotron uses a constant magnetic field and a constant-frequency applied electric field. One of the two fields is varied in a synchrocyclotron: Both of these fields are varied in a synchrotron. Thus, a synchrotron is a particular type of cyclic particle accelerator in which a magnetic field is used to turn the particles so they circulate and an electric field is used to accelerate the particles. The synchroton carefully synchronizes the applied fields with the travelling particle beam.
By increasing the applied magnetic fields appropriately as the particles gain energy, the charged particles path is held constant as the charged particles are accelerated, allowing the vacuum container for the particles to be a large thin torus. In reality it is easier to use some straight sections between the bending magnets and some turning sections giving the torus the shape of a round-cornered polygon. A path of large effective radius is thus constructed using simple straight and curved pipe segments, unlike the disc-shaped chamber of the cyclotron type devices. The shape also allows and requires the use of multiple magnets to bend the particle beam.
The maximum energy that a cyclic accelerator can impart is typically limited by the strength of the magnetic fields and the minimum radius/maximum curvature of the particle path. In a cyclotron the maximum radius is quite limited as the particles start at the center and spiral outward, thus this entire path must be a self-supporting disc-shaped evacuated chamber. Since the radius is limited, the power of the machine becomes limited by the strength of the magnetic field. In the case of an ordinary electromagnet, the field strength is limited by the saturation of the core because when all magnetic domains are aligned the field can not be further increased to any practical extent. The arrangement of the single pair of magnets also limits the economic size of the device.
Synchrotrons overcome these limitations, using a narrow beam pipe surrounded by much smaller and more tightly focusing magnets. The ability of a synchrotron to accelerate particles is limited by the fact that the particles must be charged to be accelerated at all, but charged particles under acceleration emit photons, thereby losing energy. The limiting beam energy is reached when the energy lost to the lateral acceleration required to maintain the beam path in a circle equals the energy added each cycle. More powerful accelerators are built by using large radius paths and by using more numerous and more powerful microwave cavities to accelerate the particle beam between corners. Lighter particles, such as electrons, lose a larger fraction of their energy when turning. Practically speaking, the energy of electron/positron accelerators is limited by this radiation loss, while it does not play a significant role in the dynamics of proton or ion accelerators. The energy of those is limited strictly by the strength of magnets and by the cost.
Charged Particle Beam Therapy
Throughout this document, a charged particle beam therapy system, such as a proton beam, hydrogen ion beam, or carbon ion beam, is described. Herein, the charged particle beam therapy system is described using a proton beam. However, the aspects taught and described in terms of a proton beam are not intended to be limiting to that of a proton beam and are illustrative of a charged particle beam system. Any charged particle beam system is equally applicable to the techniques described herein.
Referring now to FIG. 1, a charged particle beam system 100 is illustrated. The charged particle beam preferably comprises a number of subsystems including any of: a main controller 110; an injection system 120; a synchrotron 130 that typically includes: (1) an accelerator system 132 and (2) an extraction system 134; a scanning/targeting/delivery system 140; a patient interface module 150; a display system 160; and/or an imaging system 170.
An exemplary method of use of the charged particle beam system 100 is provided. The main controller 110 controls one or more of the subsystems to accurately and precisely deliver protons to a tumor of a patient. For example, the main controller 110 obtains an image, such as a portion of a body and/or of a tumor, from the imaging system 170. The main controller 110 also obtains position and/or timing information from the patient interface module 150. The main controller 110 then optionally controls the injection system 120 to inject a proton into a synchrotron 130. The synchrotron typically contains at least an accelerator system 132 and an extraction system 134. The main controller preferably controls the proton beam within the accelerator system, such as by controlling speed, trajectory, and timing of the proton beam. The main controller then controls extraction of a proton beam from the accelerator through the extraction system 134. For example, the controller controls timing and/or energy of the extracted beam. The controller 110 also preferably controls targeting of the proton beam through the scanning/targeting/delivery system 140 to the patient interface module 150. One or more components of the patient interface module 150, such as translational and rotational position of the patient, are preferably controlled by the main controller 110. Further, display elements of the display system 160 are preferably controlled via the main controller 110. Displays, such as display screens, are typically provided to one or more operators and/or to one or more patients. In one embodiment, the main controller 110 times the delivery of the proton beam from all systems, such that protons are delivered in an optimal therapeutic manner to the tumor of the patient.
Herein, the main controller 110 refers to a single system controlling the charged particle beam system 100, to a single controller controlling a plurality of subsystems controlling the charged particle beam system 100, or to a plurality of individual controllers controlling one or more sub-systems of the charged particle beam system 100.
Referring now to FIG. 2, an illustrative exemplary embodiment of one version of the charged particle beam system 100 is provided. The number, position, and described type of components is illustrative and non-limiting in nature. In the illustrated embodiment, the injection system 120 or ion source or charged particle beam source generates protons. The protons are delivered into a vacuum tube that runs into, through, and out of the synchrotron. The generated protons are delivered along an initial path 262. Focusing magnets 230, such as quadrupole magnets or injection quadrupole magnets, are used to focus the proton beam path. A quadrupole magnet is a focusing magnet. An injector bending magnet 232 bends the proton beam toward the plane of the synchrotron 130. The focused protons having an initial energy are introduced into an injector magnet 240, which is preferably an injection Lamberson magnet. Typically, the initial beam path 262 is along an axis off of, such as above, a circulating plane of the synchrotron 130. The injector bending magnet 232 and injector magnet 240 combine to move the protons into the synchrotron 130. Main bending magnets, dipole magnets, or circulating magnets 250 are used to turn the protons along a circulating beam path 264. A dipole magnet is a bending magnet. The main bending magnets 250 bend the initial beam path 262 into a circulating beam path 264. In this example, the main bending magnets 250 or circulating magnets are represented as four sets of four magnets to maintain the circulating beam path 264 into a stable circulating beam path. However, any number of magnets or sets of magnets are optionally used to move the protons around a single orbit in the circulation process. The protons pass through an accelerator 270. The accelerator accelerates the protons in the circulating beam path 264. As the protons are accelerated, the fields applied by the magnets are increased. Particularly, the speed of the protons achieved by the accelerator 270 are synchronized with magnetic fields of the main bending magnets 250 or circulating magnets to maintain stable circulation of the protons about a central point or region 280 of the synchrotron. At separate points in time the accelerator 270/main bending magnet 250 combination is used to accelerate and/or decelerate the circulating protons while maintaining the protons in the circulating path or orbit. An extraction element of the infector/deflector system 290 is used in combination with a Lamberson extraction magnet 292 to remove protons from their circulating beam path 264 within the synchrotron 130. One example of a deflector component is a Lamberson magnet. Typically the deflector moves the protons from the circulating plane to an axis off of the circulating plane, such as above the circulating plane. Extracted protons are preferably directed and/or focused using an extraction bending magnet 237 and extraction focusing magnets 235, such as quadrupole magnets along a transport path 268 into the scanning/targeting/delivery system 140. Two components of a scanning system 140 or targeting system typically include a first axis control 142, such as a vertical control, and a second axis control 144, such as a horizontal control. In one embodiment, the first axis control 142 allows for about 100 mm of vertical or y-axis scanning of the proton beam 268 and the second axis control 144 allows for about 700 mm of horizontal or x-axis scanning of the proton beam 268. Protons are delivered with control to the patient interface module 150 and to a tumor of a patient. All of the above listed elements are optional and may be used in various permutations and combinations. Each of the above listed elements are further described, infra.
Ion Beam Generation System
An ion beam generation system generates a negative ion beam, such as a hydrogen anion or H− beam; preferably focuses the negative ion beam; converts the negative ion beam to a positive ion beam, such as a proton or H+ beam; and injects the positive ion beam 262 into the synchrotron 130. Portions of the ion beam path are preferably under partial vacuum. Each of these systems are further described, infra.
Referring now to FIG. 3, an exemplary ion beam generation system 300 is illustrated. As illustrated, the ion beam generation system 300 has four major subsections: a negative ion source 310, a first partial vacuum system 330, an optional ion beam focusing system 350, and a tandem accelerator 390.
Still referring to FIG. 3, the negative ion source 310 preferably includes an inlet port 312 for injection of hydrogen gas into a high temperature plasma chamber 314. In one embodiment, the plasma chamber includes a magnetic material 316, which provides a magnetic field 317 between the high temperature plasma chamber 314 and a low temperature plasma region on the opposite side of the magnetic field barrier. An extraction pulse is applied to a negative ion extraction electrode 318 to pull the negative ion beam into a negative ion beam path 319, which proceeds through the first partial vacuum system 330, through the ion beam focusing system 350, and into the tandem accelerator 390.
Still referring to FIG. 3, the first partial vacuum system 330 is an enclosed system running from the hydrogen gas inlet port 312 to a foil 395 in the tandem accelerator 390. The foil 395 is preferably sealed directly or indirectly to the edges of the vacuum tube 320 providing for a higher pressure, such as about 10−5 torr, to be maintained on the first partial vacuum system 330 side of the foil 395 and a lower pressure, such as about 10−7 torr, to be maintained on the synchrotron side of the foil 390. By only pumping first partial vacuum system 330 and by only semi-continuously operating the ion beam source vacuum based on sensor readings, the lifetime of the semi-continuously operating pump is extended. The sensor readings are further described, infra.
Still referring to FIG. 3, the first partial vacuum system 330 preferably includes: a first pump 332, such as a continuously operating pump and/or a turbo molecular pump; a large holding volume 334; and a semi-continuously operating pump 336. Preferably, a pump controller 340 receives a signal from a pressure sensor 342 monitoring pressure in the large holding volume 334. Upon a signal representative of a sufficient pressure in the large holding volume 334, the pump controller 340 instructs an actuator 345 to open a valve 346 between the large holding volume and the semi-continuously operating pump 336 and instructs the semi-continuously operating pump to turn on and pump to atmosphere residual gases out of the vacuum line 320 about the charged particle stream. In this fashion, the lifetime of the semi-continuously operating pump is extended by only operating semi-continuously and as needed. In one example, the semi-continuously operating pump 336 operates for a few minutes every few hours, such as 5 minutes every 4 hours, thereby extending a pump with a lifetime of about 2,000 hours to about 96,000 hours.
Further, by isolating the inlet gas from the synchrotron vacuum system, the synchrotron vacuum pumps, such as turbo molecular pumps can operate over a longer lifetime as the synchrotron vacuum pumps have fewer gas molecules to deal with. For example, the inlet gas is primarily hydrogen gas but may contain impurities, such as nitrogen and carbon dioxide. By isolating the inlet gases in the negative ion source system 310, first partial vacuum system 330, ion beam focusing system 350, and negative ion beam side of the tandem accelerator 390, the synchrotron vacuum pumps can operate at lower pressures with longer lifetimes, which increases operating efficiency of the synchrotron 130.
Still referring to FIG. 3, the optimal ion beam focusing system 350 preferably includes two or more electrodes where one electrode of each electrode pair partially obstructs the ion beam path with conductive paths 372, such as a conductive mesh. In the illustrated example, three ion beam focusing system sections are illustrated, a two electrode ion beam focusing section 360, a first three electrode ion beam focusing section 370, and a second three electrode ion beam focusing section 380. For a given electrode pair, electric field lines, running between the conductive mesh of a first electrode and a second electrode, provide inward forces focusing the negative ion beam. Multiple such electrode pairs provide multiple negative ion beam focusing regions. Preferably the two electrode ion focusing section 360, first three electrode ion focusing section 370, and second three electrode ion focusing section 380 are placed after the negative ion source and before the tandem accelerator and/or cover a space of about 0.5, 1, or 2 meters along the ion beam path. Ion beam focusing systems are further described, infra.
Still referring to FIG. 3, the tandem accelerator 390 preferably includes a foil 395, such as a carbon foil. The negative ions in the negative ion beam path 319 are converted to positive ions, such as protons, and the initial ion beam path 262 results. The foil 395 is preferably sealed directly or indirectly to the edges of the vacuum tube 320 providing for a higher pressure, such as about 10−5 torr, to be maintained on the side of the foil 395 having the negative ion beam path 319 and a lower pressure, such as about 10−7 torr, to be maintained on the side of the foil 390 having the proton ion beam path 262. Having the foil 395 physically separating the vacuum chamber 320 into two pressure regions allows for a system having fewer and/or smaller pumps to maintain the lower pressure system in the synchrotron 130 as the inlet hydrogen and its residuals are extracted in a separate contained and isolated space by the first partial vacuum system 330.
Negative Ion Source
An example of the negative ion source 310 is further described herein. Referring now to FIG. 4, a cross-section of an exemplary negative ion source system 400 is provided. The negative ion beam 319 is created in multiple stages. During a first stage, hydrogen gas is injected into a chamber. During a second stage, a negative ion is created by application of a first high voltage pulse, which creates a plasma about the hydrogen gas to create negative ions. During a third stage, a magnetic field filter is applied to components of the plasma. During a fourth stage, the negative ions are extracted from a low temperature plasma region, on the opposite side of the magnetic field barrier, by application of a second high voltage pulse. Each of the four stages are further described, infra. While the chamber is illustrated as a cross-section of a cylinder, the cylinder is exemplary only and any geometry applies to the magnetic loop containment walls, described infra.
In the first stage, hydrogen gas 440 is injected through the inlet port 312 into a high temperature plasma region 490. The injection port 312 is open for a short period of time, such as less than about 1, 5, or 10 microseconds to minimize vacuum pump requirements to maintain vacuum chamber 320 requirements. The high temperature plasma region is maintained at reduced pressure by the partial vacuum system 330. The injection of the hydrogen gas is optionally controlled by the main controller 110, which is responsive to imaging system 170 information and patient interface module 150 information, such as patient positioning and period in a breath cycle.
In the second stage, a high temperature plasma region is created by applying a first high voltage pulse across a first electrode 422 and a second electrode 424. For example a 5 kV pulse is applied for about 20 microseconds with 5 kV at the second electrode 424 and about 0 kV applied at the first electrode 422. Hydrogen in the chamber is broken, in the high temperature plasma region 490, into component parts, such as any of: atomic hydrogen, H0, a proton, H+, an electron, e−, and a hydrogen anion, H−. An example of a high voltage pulse is a pulse of at least 4 kilovolts for a period of at least 15 microseconds.
In the third stage, the high temperature plasma region 490 is at least partially separated from a low temperature plasma region 492 by the magnetic field 317 or in this specific example a magnetic field barrier 430. High energy electrons are restricted from passing through the magnetic field barrier 430. In this manner, the magnetic field barrier 430 acts as a filter between, zone A and zone B, in the negative ion source. Preferably, a central magnetic material 410, which is an example of the magnetic material 316, is placed within the high temperature plasma region 490, such as along a central axis of the high temperature plasma region 490. Preferably, the first electrode 422 and second electrode 424 are composed of magnetic materials, such as iron. Preferably, the outer walls 450 of the high temperature plasma region, such as cylinder walls, are composed of a magnetic material, such as a permanent magnet, ferric or iron based material, or a ferrite dielectric ring magnet. In this manner a magnetic field loop is created by: the central magnetic material 410, first electrode 422, the outer walls 450, the second electrode 424, and the magnetic field barrier 430. Again, the magnetic field barrier 430 restricts high energy electrons from passing through the magnetic field barrier 430. Low energy electrons interact with atomic hydrogen, H0, to create a hydrogen anion, H−, in the low temperature plasma region 492.
In the fourth stage, a second high voltage pulse or extraction pulse is applied at a third electrode 426. The second high voltage pulse is preferentially applied during the later period of application of the first high voltage pulse. For example, an extraction pulse of about 25 kV is applied for about the last 5 microseconds of the first creation pulse of about 20 microseconds. In a second example, timing of the extraction pulse overlaps a period of the first high voltage pulse, such as for about, 1, 3, 5, or 10 microseconds. The potential difference, of about 20 kV, between the third electrode 426 and second electrode 424 extracts the negative ion, H−, from the low temperature plasma region 492 and initiates the negative ion beam 319, from zone B to zone C.
The magnetic field barrier 430 is optionally created in number of ways. An example of creation of the magnetic field barrier 430 using coils is provided. In this example, the elements described, supra, in relation to FIG. 4 are maintained with several differences. First, the magnetic field is created using coils. An isolating material is preferably provided between the first electrode 422 and the cylinder walls 450 as well as between the second electrode 424 and the cylinder walls 450. The central material 410 and/or cylinder walls 450 are optionally metallic. In this manner, the coils create a magnetic field loop through the first electrode 422, isolating material, outer walls 450, second electrode 424, magnetic field barrier 430, and the central material 410. Essentially, the coils generate a magnetic field in place of production of the magnetic field by the magnetic material 410. The magnetic field barrier 430 operates as described, supra. Generally, any manner that creates the magnetic field barrier 430 between the high temperature plasma region 490 and low temperature plasma region 492 is functionally applicable to the ion beam extraction system 400, described herein.
Ion Beam Focusing System
Referring now to FIG. 5, the ion beam focusing system 350 is further described. In this example, three electrodes are used. In this example, a first electrode 510 and third electrode 530 are both negatively charged and each is a ring electrode circumferentially enclosing or at least partially enclosing the negative ion beam path 319. A second electrode 520 is positively charged and is also a ring electrode at least partially and preferably substantially circumferentially enclosing the negative ion beam path. In addition, the second electrode includes one or more conducting paths 372 running through the negative ion beam path 319. For example, the conducting paths are a wire mesh, a conducting grid, or a series of substantially parallel conducting lines running across the second electrode. In use, electric field lines run from the conducting paths of the positively charged electrode to the negatively charged electrodes. For example, in use the electric field lines 540 run from the conducting paths 372 in the negative ion beam path 319 to the negatively charged electrodes 510, 530. Two ray trace lines 550, 560 of the negative ion beam path are used to illustrate focusing forces. In the first ray trace line 550, the negative ion beam encounters a first electric field line at point M. Negatively charged ions in the negative ion beam 550 encounter forces running up the electric field line 572, illustrated with an x-axis component vector 571. The x-axis component force vectors 571 alters the trajectory of the first ray trace line to a inward focused vector 552, which encounters a second electric field line at point N. Again, the negative ion beam 552 encounters forces running up the electric field line 574, illustrated as having an inward force vector with an x-axis component 573, which alters the inward focused vector 552 to a more inward focused vector 554. Similarly, in the second ray trace line 560, the negative ion beam encounters a first electric field line at point O. Negatively charged ions in the negative ion beam encounter forces running up the electric field line 576, illustrated as having a force vector with an x-axis force 575. The inward force vector 575 alters the trajectory of the second ray trace line 560 to an inward focused vector 562, which encounters a second electric field line at point P. Again, the negative ion beam encounters forces running up the electric field line 578, illustrated as having force vector with an x-axis component 577, which alters the inward focused vector 562 to a more inward focused vector 564. The net result is a focusing effect on the negative ion beam. Each of the force vectors 572, 574, 576, 578 optionally has x and/or y force vector components resulting in a 3-dimensional focusing of the negative ion beam path. Naturally, the force vectors are illustrative in nature, many electric field lines are encountered, and the focusing effect is observed at each encounter resulting in integral focusing. The example is used to illustrate the focusing effect.
Still referring to FIG. 5, optionally any number of electrodes are used, such as 2, 3, 4, 5, 6, 7, 8, or 9 electrodes, to focus the negative ion beam path where every other electrode, in a given focusing section, is either positively or negatively charged. For example, three focusing sections are optionally used. In the first ion focusing section 360, a pair of electrodes is used where the first electrode encountered along the negative ion beam path is negatively charged and the second electrode is positively charged, resulting in focusing of the negative ion beam path. In the second ion focusing section 370, two pairs of electrodes are used, where a common positively charged electrode with a conductive mesh running through the negatively ion beam path 319 is used. Thus, in the second ion focusing section 370, the first electrode encountered along the negative ion beam path is negatively charged and the second electrode is positively charged, resulting in focusing of the negative ion beam path. Further, in the second ion focusing section, moving along the negative ion beam path, a second focusing effect is observed between the second positively charged electrode and a third negatively charged electrode. In this example, a third ion focusing section 380 is used that again has three electrodes, which acts in the fashion of the second ion focusing section, describe supra.
Referring now to FIG. 6, the central region of the electrodes in the ion beam focusing system 350 is further described. Referring now to FIG. 6A, the central region of the negatively charged ring electrode 510 is preferably void of conductive material. Referring now to FIGS. 6B-D, the central region of positively charged electrode ring 520 preferably contains conductive paths 372. Preferably, the conductive paths 372 or conductive material within the positively charged electrode ring 520 blocks about 1, 2, 5, or 10 percent of the area and more preferably blocks about 5 percent of the cross-sectional area of the negative ion beam path 319. Referring now to FIG. 6B, one option is a conductive mesh 610. Referring now to FIG. 6C, a second option is a series of conductive lines 620 running substantially in parallel across the positively charged electrode ring 520 that surrounds a portion of the negative ion beam path 319. Referring now to FIG. 6D, a third option is to have a foil 630 or metallic layer cover all of the cross-sectional area of the negative ion beam path with holes punched through the material, where the holes take up about 90-99 percent and more preferably about 95 percent of the area of the foil. More generally, the pair of electrodes 510, 520 are configured to provide electric field lines that provide focusing force vectors to the negative ion beam 319 when the ions in the negative ion beam 319 translate through the electric field lines, as described supra.
In an example of a two electrode negative beam ion focusing system having a first cross-sectional diameter, d1, the negative ions are focused to a second cross-sectional diameter, d2, where d1>d2. Similarly, in an example of a three electrode negative beam ion focusing system having a first ion beam cross-sectional diameter, d1, the negative ions are focused using the three electrode system to a third negative ion beam cross-sectional diameter, d3, where d1>d3. For like potentials on the electrodes, the three electrode system provides tighter or stronger focusing compared to the two-electrode system, d3<d2.
In the examples provided, supra, of a multi-electrode ion beam focusing system, the electrodes are rings. More generally, the electrodes are of any geometry sufficient to provide electric field lines that provide focusing force vectors to the negative ion beam when the ions in the negative ion beam 319 translate through the electric field lines, as described supra. For example, one negative ring electrode is optionally replaced by a number of negatively charged electrodes, such as about 2, 3, 4, 6, 8, 10, or more electrodes placed about the outer region of a cross-sectional area of the negative ion beam probe. Generally, more electrodes are required to converge or diverge a faster or higher energy beam.
In another embodiment, by reversing the polarity of electrodes in the above example, the negative ion beam is made to diverge. Thus, the negative ion beam path 319 is optionally focused and/or expanded using combinations of electrode pairs. For example, if the electrode having the mesh across the negative ion beam path is made negative, then the negative ion beam path is made to defocus. Hence, combinations of electrode pairs are used for focusing and defocusing a negative ion beam path, such as where a first pair includes a positively charged mesh for focusing and a where a second pair includes a negatively charged mesh for defocusing.
Tandem Accelerator
Referring now to FIG. 7A, the tandem accelerator 390 is further described. The tandem accelerator accelerates ions using a series of electrodes 710, 711, 712, 713, 714, 715. For example, negative ions, such as H−, in the negative ion beam path are accelerated using a series of electrodes having progressively higher voltages relative to the voltage of the extraction electrode 426, or third electrode 426, of the negative ion beam source 310. For instance, the tandem accelerator 390 optionally has electrodes ranging from the 25 kV of the extraction electrode 426 to about 525 kV near the foil 395 in the tandem accelerator 390. Upon passing through the foil 395, the negative ion, H−, loses two electrons to yield a proton, H+, according to equation 1.

H−→H++2e−  (eq. 1)

The proton is further accelerated in the tandem accelerator using appropriate voltages at a multitude of further electrodes 713, 714, 715. The protons are then injected into the synchrotron 130 as described, supra.
Still referring to FIG. 7, the foil 395 in the tandem accelerator 390 is further described. The foil 395 is preferably a very thin carbon film of about 30 to 200 angstroms in thickness. The foil thickness is designed to both: (1) not block the ion beam and (2) allow the transfer of electrons yielding protons to form the proton beam path 262. The foil 395 is preferably substantially in contact with a support layer 720, such as a support grid. The support layer 720 provides mechanical strength to the foil 395 to combine to form a vacuum blocking element. The foil 395 blocks nitrogen, carbon dioxide, hydrogen, and other gases from passing and thus acts as a vacuum barrier. In one embodiment, the foil 395 is preferably sealed directly or indirectly to the edges of the vacuum tube 320 providing for a higher pressure, such as about 10−5 torr, to be maintained on the side of the foil 395 having the negative ion beam path 319 and a lower pressure, such as about 10−7 torr, to be maintained on the side of the foil 395 having the proton ion beam path 262. Having the foil 395 physically separating the vacuum chamber 320 into two pressure regions allows for a vacuum system having fewer and/or smaller pumps to maintain the lower pressure system in the synchrotron 130 as the inlet hydrogen and its residuals are extracted in a separate contained and isolated space by the first partial vacuum system 330. The foil 395 and support layer 720 are preferably attached to the structure 750 of the tandem accelerator 390 or vacuum tube 320 to form a pressure barrier using any mechanical means, such as a metal, plastic, or ceramic ring 730 compressed to the walls with an attachment screw 740. Any mechanical means for separating and sealing the two vacuum chamber sides with the foil 395 are equally applicable to this system. Referring now to FIGS. 7B and 7C, the support structure 720 and foil 395 are individually viewed in the x-, y-plane.
Referring now to FIG. 8, another exemplary method of use of the charged particle beam system 100 is provided. The main controller 110, or one or more sub-controllers, controls one or more of the subsystems to accurately and precisely deliver protons to a tumor of a patient. For example, the main controller sends a message to the patient indicating when or how to breath. The main controller 110 obtains a sensor reading from the patient interface module, such as a temperature breath sensor or a force reading indicative of where in a breath cycle the subject is. Coordinated at a specific and reproducible point in the breath cycle, the main controller collects an image, such as a portion of a body and/or of a tumor, from the imaging system 170. The main controller 110 also obtains position and/or timing information from the patient interface module 150. The main controller 110 then optionally controls the injection system 120 to inject hydrogen gas into a negative ion beam source 310 and controls timing of extraction of the negative ion from the negative ion beam source 310. Optionally, the main controller controls ion beam focusing the ion beam focusing lens system 350; acceleration of the proton beam with the tandem accelerator 390; and/or injection of the proton into the synchrotron 130. The synchrotron typically contains at least an accelerator system 132 and an extraction system 134. The synchrotron preferably contains one or more of: turning magnets and edge focusing magnets, which are optionally under control by the main controller 110. The main controller preferably controls the proton beam within the accelerator system, such as by controlling speed, trajectory, and/or timing of the proton beam. The main controller then controls extraction of a proton beam from the accelerator through the extraction system 134. For example, the controller controls timing, energy, and/or intensity of the extracted beam. The main controller 110 also preferably controls targeting of the proton beam through the targeting/delivery system 140 to the patient interface module 150. One or more components of the patient interface module 150 are preferably controlled by the main controller 110, such as vertical position of the patient, rotational position of the patient, and patient chair positioning/stabilization/immobilization/control elements. Further, display elements of the display system 160 are preferably controlled via the main controller 110. Displays, such as display screens, are typically provided to one or more operators and/or to one or more patients. In one embodiment, the main controller 110 times the delivery of the proton beam from all systems, such that protons are delivered in an optimal therapeutic manner to the tumor of the patient.
Synchrotron
Herein, the term synchrotron is used to refer to a system maintaining the charged particle beam in a circulating path; however, cyclotrons are alternatively used, albeit with their inherent limitations of energy, intensity, and extraction control. Further, the charged particle beam is referred to herein as circulating along a circulating path about a central point of the synchrotron. The circulating path is alternatively referred to as an orbiting path; however, the orbiting path does not refer a perfect circle or ellipse, rather it refers to cycling of the protons around a central point or region 280.
Circulating System
Referring now to FIG. 9, the synchrotron 130 preferably comprises a combination of straight sections 910 and ion beam turning sections 920. Hence, the circulating path of the protons is not circular in a synchrotron, but is rather a polygon with rounded corners.
In one illustrative embodiment, the synchrotron 130, which as also referred to as an accelerator system, has four straight elements and four turning sections. Examples of straight sections 910 include the: inflector 240, accelerator 270, extraction system 290, and deflector 292. Along with the four straight sections are four ion beam turning sections 920, which are also referred to as magnet sections or turning sections. Turning sections are further described, infra.
Referring still to FIG. 9, an exemplary synchrotron is illustrated. In this example, protons delivered along the initial proton beam path 262 are inflected into the circulating beam path with the inflector 240 and after acceleration are extracted via a deflector 292 to the beam transport path 268. In this example, the synchrotron 130 comprises four straight sections 910 and four bending or turning sections 920 where each of the four turning sections use one or more magnets to turn the proton beam about ninety degrees. As is further described, infra, the ability to closely space the turning sections and efficiently turn the proton beam results in shorter straight sections. Shorter straight sections allows for a synchrotron design without the use of focusing quadrupoles in the circulating beam path of the synchrotron. The removal of the focusing quadrupoles from the circulating proton beam path results in a more compact design. In this example, the illustrated synchrotron has about a five meter diameter versus eight meter and larger cross-sectional diameters for systems using a quadrupole focusing magnet in the circulating proton beam path.
Referring now to FIG. 10, additional description of the first bending or turning section 920 is provided. Each of the turning sections preferably comprise multiple magnets, such as about 2, 4, 6, 8, 10, or 12 magnets. In this example, four turning magnets 1010, 1020, 1030, 1040 in the first turning section 920 are used to illustrate key principles, which are the same regardless of the number of magnets in a turning section 920. The turning magnets 1010, 1020, 1030, 1040 are particular types of main bending or circulating magnets 250.
In physics, the Lorentz force is the force on a point charge due to electromagnetic fields. The Lorentz force is given by equation 2 in terms of magnetic fields with the election field terms not included.

F=q(v×B)  (eq. 2)

In equation 2, F is the force in newtons; q is the electric charge in coulombs; B is the magnetic field in Teslas; and v is the instantaneous velocity of the particles in meters per second.
Referring now to FIG. 11, an example of a single magnet bending or turning section 1010 is expanded. The turning section includes a gap 1110 through which protons circulate. The gap 1110 is preferably a flat gap, allowing for a magnetic field across the gap 1110 that is more uniform, even, and intense. A magnetic field enters the gap 1110 through a magnetic field incident surface and exits the gap 1110 through a magnetic field exiting surface. The gap 1110 runs in a vacuum tube between two magnet halves. The gap 1110 is controlled by at least two parameters: (1) the gap 1110 is kept as large as possible to minimize loss of protons and (2) the gap 1110 is kept as small as possible to minimize magnet sizes and the associated size and power requirements of the magnet power supplies. The flat nature of the gap 1110 allows for a compressed and more uniform magnetic field across the gap 1110. One example of a gap dimension is to accommodate a vertical proton beam size of about 2 cm with a horizontal beam size of about 5 to 6 cm.
As described, supra, a larger gap size requires a larger power supply. For instance, if the gap 1110 size doubles in vertical size, then the power supply requirements increase by about a factor of 4. The flatness of the gap 1110 is also important. For example, the flat nature of the gap 1110 allows for an increase in energy of the extracted protons from about 250 to about 330 MeV. More particularly, if the gap 1110 has an extremely flat surface, then the limits of a magnetic field of an iron magnet are reachable. An exemplary precision of the flat surface of the gap 1110 is a polish of less than about 5 microns and preferably with a polish of about 1 to 3 microns. Unevenness in the surface results in imperfections in the applied magnetic field. The polished flat surface spreads unevenness of the applied magnetic field.
Still referring to FIG. 11, the charged particle beam moves through the gap 1110 with an instantaneous velocity, v. A first magnetic coil 1120 and a second magnetic coil 1130 run above and below the gap 1110, respectively. Current running through the coils 1120, 1130 results in a magnetic field, B, running through the single magnet turning section 1010. In this example, the magnetic field, B, runs upward, which results in a force, F, pushing the charged particle beam inward toward a central point of the synchrotron, which turns the charged particle beam in an arc.
Still referring to FIG. 11, a portion of an optional second magnet bending or turning section 1020 is illustrated. The coils 1120, 1130 typically have return elements 1140, 1150 or turns at the end of one magnet, such as at the end of the first magnet turning section 1010. The turns 1140, 1150 take space. The space reduces the percentage of the path about one orbit of the synchrotron that is covered by the turning magnets. This leads to portions of the circulating path where the protons are not turned and/or focused and allows for portions of the circulating path where the proton path defocuses. Thus, the space results in a larger synchrotron. Therefore, the space between magnet turning sections 1160 is preferably minimized. The second turning magnet is used to illustrate that the coils 1120, 1130 optionally run along a plurality of magnets, such as 2, 3, 4, 5, 6, or more magnets. Coils 1120, 1130 running across multiple turning section magnets allows for two turning section magnets to be spatially positioned closer to each other due to the removal of the steric constraint of the turns, which reduces and/or minimizes the space 1160 between two turning section magnets.
Referring now to FIGS. 12 and 13, two illustrative 90 degree rotated cross-sections of single magnet bending or turning sections 1010 are presented. The magnet assembly has a first magnet 1210 and a second magnet 1220. A magnetic field induced by coils, described infra, runs between the first magnet 1210 to the second magnet 1220 across the gap 1110. Return magnetic fields run through a first yoke 1212 and second yoke 1222. The combined cross-section area of the return yokes roughly approximates the cross-sectional area of the first magnet 1210 or second magnet 1220. The charged particles run through the vacuum tube in the gap 1110. As illustrated, protons run into FIG. 12 through the gap 1110 and the magnetic field, illustrated as vector B, applies a force F to the protons pushing the protons towards the center of the synchrotron, which is off page to the right in FIG. 12. The magnetic field is created using windings. A first coil making up a first winding coil 1250, illustrated as a filled area in FIG. 12 to representatively present cross-sections of the wire for individual windings and illustrated as winding coils in FIG. 13. The second coil of wire making up a second winding coil 1260 is similarly illustratively represented. Isolating or concentrating gaps 1230, 1240, such as air gaps, isolate the iron based yokes from the gap 1110. The gap 1110 is approximately flat to yield a uniform magnetic field across the gap 1110, as described supra.
Still referring to FIG. 13, the ends of a single bending or turning magnet are preferably beveled. Nearly perpendicular or right angle edges of a turning magnet 1010 are represented by dashed lines 1374, 1384. The dashed lines 1374, 1384 intersect at a point 1390 beyond the center of the synchrotron 280. Preferably, the edge of the turning magnet is beveled at angles alpha, α, and beta, β, which are angles formed by a first line 1372, 1382 going from an edge of the turning magnet 1010 and the center 280 and a second line 1374, 1384 going from the same edge of the turning magnet and the intersecting point 1390. The angle alpha is used to describe the effect and the description of angle alpha applies to angle beta, but angle alpha is optionally different from angle beta. The angle alpha provides an edge focusing effect. Beveling the edge of the turning magnet 1010 at angle alpha focuses the proton beam.
Multiple turning magnets provide multiple magnet edges that each have edge focusing effects in the synchrotron 130. If only one turning magnet is used, then the beam is only focused once for angle alpha or twice for angle alpha and angle beta. However, by using smaller turning magnets, more turning magnets fit into the turning sections 920 of the synchrotron 130. For example, if four magnets are used in a turning section 920 of the synchrotron, then for a single turning section there are eight possible edge focusing effect surfaces, two edges per magnet. The eight focusing surfaces yield a smaller cross-sectional beam size, which allows the use of a smaller gap.
The use of multiple edge focusing effects in the turning magnets results in not only a smaller gap 1110, but also the use of smaller magnets and smaller power supplies. For a synchrotron 130 having four turning sections 920 where each turning sections has four turning magnets and each turning magnet has two focusing edges, a total of thirty-two focusing edges exist for each orbit of the protons in the circulating path of the synchrotron 130. Similarly, if 2, 6, or 8 magnets are used in a given turning section, or if 2, 3, 5, or 6 turning sections are used, then the number of edge focusing surfaces expands or contracts according to equation 3.




  
    
      
        TFE
        =
        
          NTS
          *
          
            M
            NTS
          
          *
          
            FE
            M
          
        
      
    
    
      
        (
        
          eq
          .
          
            
          
          ⁢
          3
        
        )
      
    
  




where TFE is the number of total focusing edges, NTS is the number of turning sections, M is the number of magnets, and FE is the number of focusing edges. Naturally, not all magnets are necessarily beveled and some magnets are optionally beveled on only one edge.

The inventors have determined that multiple smaller magnets have benefits over fewer larger magnets. For example, the use of 16 small magnets yields 32 focusing edges whereas the use of 4 larger magnets yields only 8 focusing edges. The use of a synchrotron having more focusing edges results in a circulating path of the synchrotron built without the use of focusing quadrupole magnets. All prior art synchrotrons use quadrupoles in the circulating path of the synchrotron. Further, the use of quadrupoles in the circulating path necessitates additional straight sections in the circulating path of the synchrotron. Thus, the use of quadrupoles in the circulating path of a synchrotron results in synchrotrons having larger diameters, larger circulating beam pathlengths, and/or larger circumferences.
In various embodiments of the system described herein, the synchrotron has any combination of:

    
    
        at least 4 and preferably 6, 8, 10, or more edge focusing edges per 90 degrees of turn of the charged particle beam in a synchrotron having four turning sections;
        at least about 16 and preferably about 24, 32, or more edge focusing edges per orbit of the charged particle beam in the synchrotron;
        only 4 turning sections where each of the turning sections includes at least 4 and preferably 8 edge focusing edges;
        an equal number of straight sections and turning sections;
        exactly 4 turning sections;
        at least 4 focusing edges per turning section;
        no quadrupoles in the circulating path of the synchrotron;
        a rounded corner rectangular polygon configuration;
        a circumference of less than 60 meters;
        a circumference of less than 60 meters and 32 edge focusing surfaces; and/or
        any of about 8, 16, 24, or 32 non-quadrupole magnets per circulating path of the synchrotron, where the non-quadrupole magnets include edge focusing edges.

Flat Gap Surface

    
    


While the gap surface is described in terms of the first turning magnet 1010, the discussion applies to each of the turning magnets in the synchrotron. Similarly, while the gap 1110 surface is described in terms of the magnetic field incident surface 670, the discussion additionally optionally applies to the magnetic field exiting surface 680.
Referring again to FIG. 12, the incident magnetic field surface 1270 of the first magnet 1210 is further described. FIG. 12 is not to scale and is illustrative in nature. Local imperfections or unevenness in quality of the finish of the incident surface 1270 results in inhomogeneities or imperfections in the magnetic field applied to the gap 1110. The magnetic field incident surface 1270 and/or exiting surface 1280 of the first magnet 1210 is preferably about flat, such as to within about a zero to three micron finish polish or less preferably to about a ten micron finish polish. By being very flat, the polished surface spreads the unevenness of the applied magnetic field across the gap 1110. The very flat surface, such as about 0, 1, 2, 4, 6, 8, 10, 15, or 20 micron finish, allows for a smaller gap size, a smaller applied magnetic field, smaller power supplies, and tighter control of the proton beam cross-sectional area.
Referring now to FIG. 14A and FIG. 14B, the accelerator system 270, such as a radio-frequency (RF) accelerator system, is further described. The accelerator includes a series of coils 1410-1419, such as iron or ferrite coils, each circumferentially enclosing the vacuum system 320 through which the proton beam 264 passes in the synchrotron 130. Referring now to FIG. 14B, the first coil 1410 is further described. A loop of standard wire 1430 completes at least one turn about the first coil 1410. The loop attaches to a microcircuit 1420. Referring again to FIG. 14A, an RF synthesizer 1440, which is preferably connected to the main controller 110, provides a low voltage RF signal that is synchronized to the period of circulation of protons in the proton beam path 264. The RF synthesizer 1440, microcircuit 1420, loop 1430, and coil 1410 combine to provide an accelerating voltage to the protons in the proton beam path 264. For example, the RF synthesizer 1440 sends a signal to the microcircuit 1420, which amplifies the low voltage RF signal and yields an acceleration voltage, such as about 10 volts. The actual acceleration voltage for a single microcircuit/loop/coil combination is about 5, 10, 15, or 20 volts, but is preferably about 10 volts. Preferably, the RF-amplifier microcircuit and accelerating coil are integrated.
Still referring to FIG. 14A, the integrated RF-amplifier microcircuit and accelerating coil presented in FIG. 14B is repeated, as illustrated as the set of coils 1411-1419 surrounding the vacuum tube 320. For example, the RF-synthesizer 1440, under main controller 130 direction, sends an RF-signal to the microcircuits 1420-1429 connected to coils 1410-1419, respectively. Each of the microcircuit/loop/coil combinations generates a proton accelerating voltage, such as about 10 volts each. Hence, a set of five coil combinations generates about 50 volts for proton acceleration. Preferably about 5 to 20 microcircuit/loop/coil combinations are used and more preferably about 9 or 10 microcircuit/loop/coil combinations are used in the accelerator system 270.
As a further clarifying example, the RF synthesizer 1440 sends an RF-signal, with a period equal to a period of circulation of a proton about the synchrotron 130, to a set of ten microcircuit/loop/coil combinations, which results in about 100 volts for acceleration of the protons in the proton beam path 264. The 100 volts is generated at a range of frequencies, such as at about 1 MHz for a low energy proton beam to about 15 MHz for a high energy proton beam. The RF-signal is optionally set at an integer multiple of a period of circulation of the proton about the synchrotron circulating path. Each of the microcircuit/loop/coil combinations are optionally independently controlled in terms of acceleration voltage and frequency.
Integration of the RF-amplifier microcircuit and accelerating coil, in each microcircuit/loop/coil combination, results in three considerable advantages. First, for synchrotrons, the prior art does not use microcircuits integrated with the accelerating coils but rather uses a set of long cables to provide power to a corresponding set of coils. The long cables have an impedance/resistance, which is problematic for high frequency RF control. As a result, the prior art system is not operable at high frequencies, such as above about 10 MHz. The integrated RF-amplifier microcircuit/accelerating coil system is operable at above about 10 MHz and even 15 MHz where the impedance and/or resistance of the long cables in the prior art systems results in poor control or failure in proton acceleration. Second, the long cable system, operating at lower frequencies, costs about $50,000 and the integrated microcircuit system costs about $1000, which is 50 times less expensive. Third, the microcircuit/loop/coil combinations in conjunction with the RF-amplifier system results in a compact low power consumption design allowing production and use of a proton cancer therapy system in a small space, as described supra, and in a cost effective manner.
Referring now to FIG. 15, an example is used to clarify the magnetic field control using a feedback loop 1500 to change delivery times and/or periods of proton pulse delivery. In one case, a respiratory sensor 1510 senses the breathing cycle of the subject. The respiratory sensor sends the information to an algorithm in a magnetic field controller 1520, typically via the patient interface module 150 and/or via the main controller 110 or a subcomponent thereof. The algorithm predicts and/or measures when the subject is at a particular point in the breathing cycle, such as at the bottom of a breath. Magnetic field sensors 1530 are used as input to the magnetic field controller, which controls a magnet power supply 1540 for a given magnetic field 1550, such as within a first turning magnet 1010 of a synchrotron 130. The control feedback loop is thus used to dial the synchrotron to a selected energy level and deliver protons with the desired energy at a selected point in time, such as at the bottom of the breath. More particularly, the main controller injects protons into the synchrotron and accelerates the protons in a manner that combined with extraction delivers the protons to the tumor at a selected point in the breathing cycle. Intensity of the proton beam is also selectable and controllable by the main controller at this stage. The feedback control to the correction coils allows rapid selection of energy levels of the synchrotron that are tied to the patient's breathing cycle. This system is in stark contrast to a system where the current is stabilized and the synchrotron deliver pulses with a period, such as 10 or 20 cycles per second with a fixed period. Optionally, the feedback or the magnetic field design allows for the extraction cycle to match the varying respiratory rate of the patient.
Traditional extraction systems do not allow this control as magnets have memories in terms of both magnitude and amplitude of a sine wave. Hence, in a traditional system, in order to change frequency, slow changes in current must be used. However, with the use of the feedback loop using the magnetic field sensors, the frequency and energy level of the synchrotron are rapidly adjustable. Further aiding this process is the use of a novel extraction system that allows for acceleration of the protons during the extraction process.
Patient Positioning
Referring now to FIG. 16, the patient is preferably positioned on or within a patient translation and rotation positioning system 1610 of the patient interface module 150. The patient translation and rotation positioning system 1610 is used to translate the patient and/or rotate the patient into a zone where the proton beam can scan the tumor using a scanning system 140 or proton targeting system, described infra. Essentially, the patient positioning system 1610 performs large movements of the patient to place the tumor near the center of a proton beam path 268 and the proton scanning or targeting system 140 performs fine movements of the momentary beam position 269 in targeting the tumor 1620. To illustrate, FIG. 16A shows the momentary proton beam position 269 and a range of scannable positions 1640 using the proton scanning or targeting system 140, where the scannable positions 1640 are about the tumor 1620 of the patient 1630. In this example, the scannable positions are scanned along the x- and y-axes; however, scanning is optionally simultaneously performed along the z-axis as described infra. This illustratively shows that the y-axis movement of the patient occurs on a scale of the body, such as adjustment of about 1, 2, 3, or 4 feet, while the scannable region of the proton beam 268 covers a portion of the body, such as a region of about 1, 2, 4, 6, 8, 10, or 12 inches. The patient positioning system and its rotation and/or translation of the patient combines with the proton targeting system to yield precise and/or accurate delivery of the protons to the tumor.
Referring still to FIG. 16, the patient positioning system 1610 optionally includes a bottom unit 1612 and a top unit 1614, such as discs or a platform. Referring now to FIG. 16A, the patient positioning unit 1610 is preferably y-axis adjustable 1616 to allow vertical shifting of the patient relative to the proton therapy beam 268. Preferably, the vertical motion of the patient positioning unit 1610 is about 10, 20, 30, or 50 centimeters per minute. Referring now to FIG. 16B, the patient positioning unit 1610 is also preferably rotatable 1617 about a rotation axis, such as about the y-axis running through the center of the bottom unit 1612 or about a y-axis running through the tumor 1620, to allow rotational control and positioning of the patient relative to the proton beam path 268. Preferably the rotational motion of the patient positioning unit 1610 is about 360 degrees per minute. Optionally, the patient positioning unit rotates about 45, 90, or 180 degrees. Optionally, the patient positioning unit 1610 rotates at a rate of about 45, 90, 180, 360, 720, or 1080 degrees per minute. The rotation of the positioning unit 1617 is illustrated about the rotation axis at two distinct times, t1 and t2. Protons are optionally delivered to the tumor 1620 at n times where each of the n times represent a different relative direction of the incident proton beam 269 hitting the patient 1630 due to rotation of the patient 1617 about the rotation axis.
Any of the semi-vertical, sitting, or laying patient positioning embodiments described, infra, are optionally vertically translatable along the y-axis or rotatable about the rotation or y-axis.
Preferably, the top and bottom units 1612, 1614 move together, such that they rotate at the same rates and translate in position at the same rates. Optionally, the top and bottom units 1612, 1614 are independently adjustable along the y-axis to allow a difference in distance between the top and bottom units 1612, 1614. Motors, power supplies, and mechanical assemblies for moving the top and bottom units 1612, 1614 are preferably located out of the proton beam path 269, such as below the bottom unit 1612 and/or above the top unit 1614. This is preferable as the patient positioning unit 1610 is preferably rotatable about 360 degrees and the motors, power supplies, and mechanical assemblies interfere with the protons if positioned in the proton beam path 269
Proton Delivery Efficiency
Referring now to FIG. 17, a common distribution of relative doses for both X-rays and proton irradiation is presented. As shown, X-rays deposit their highest dose near the surface of the targeted tissue and then deposited doses exponentially decrease as a function of tissue depth. The deposition of X-ray energy near the surface is non-ideal for tumors located deep within the body, which is usually the case, as excessive damage is done to the soft tissue layers surrounding the tumor 1620. The advantage of protons is that they deposit most of their energy near the end of the flight trajectory as the energy loss per unit path of the absorber transversed by a proton increases with decreasing particle velocity, giving rise to a sharp maximum in ionization near the end of the range, referred to herein as the Bragg peak. Furthermore, since the flight trajectory of the protons is variable by increasing or decreasing the initial kinetic energy or initial velocity of the proton, then the peak corresponding to maximum energy is movable within the tissue. Thus z-axis control of the proton depth of penetration is allowed by the acceleration process. As a result of proton dose-distribution characteristics, a radiation oncologist can optimize dosage to the tumor 1620 while minimizing dosage to surrounding normal tissues.
The Bragg peak energy profile shows that protons deliver their energy across the entire length of the body penetrated by the proton up to a maximum penetration depth. As a result, energy is being delivered, in the distal portion of the Bragg peak energy profile, to healthy tissue, bone, and other body constituents before the proton beam hits the tumor. It follows that the shorter the pathlength in the body prior to the tumor, the higher the efficiency of proton delivery efficiency, where proton delivery efficiency is a measure of how much energy is delivered to the tumor relative to healthy portions of the patient. Examples of proton delivery efficiency include: (1) a ratio of proton energy delivered to the tumor over proton energy delivered to non-tumor tissue; (2) pathlength of protons in the tumor versus pathlength in the non-tumor tissue; and/or (3) damage to a tumor compared to damage to healthy body parts. Any of these measures are optionally weighted by damage to sensitive tissue, such as a nervous system element, the spinal column, brain, eye, heart, or other organ. To illustrate, for a patient in a laying position where the patient is rotated about the y-axis during treatment, a tumor near the heart would at times be treated with protons running through the head-to-heart path, leg-to-heart path, or hip-to-heart path, which are all inefficient compared to a patient in a sitting or semi-vertical position where the protons are all delivered through a shorter chest-to-heart; side-of-body-to-heart, or back-to-heart path. Particularly, compared to a laying position, using a sitting or semi-vertical position of the patient, a shorter pathlength through the body to a tumor is provided to a tumor located in the torso or head, which results in a higher or better proton delivery efficiency.
Herein proton delivery efficiency is separately described from time efficiency or synchrotron use efficiency, which is a fraction of time that the charged particle beam apparatus is in a tumor treating operation mode.
Depth Targeting
Referring now to FIGS. 18 A-E, x-axis scanning of the proton beam is illustrated while z-axis energy of the proton beam undergoes controlled variation 1800 to allow irradiation of slices of the tumor 1620. For clarity of presentation, the simultaneous y-axis scanning that is performed is not illustrated. In FIG. 18A, irradiation is commencing with the momentary proton beam position 269 at the start of a first slice. Referring now to FIG. 18B, the momentary proton beam position is at the end of the first slice. Importantly, during a given slice of irradiation, the proton beam energy is preferably continuously controlled and changed according to the tissue mass and density in front of the tumor 1620. The variation of the proton beam energy to account for tissue density thus allows the beam stopping point, or Bragg peak, to remain inside the tissue slice. The variation of the proton beam energy during scanning or during x-, y-axes scanning is possible. FIGS. 18C, 18D, and 18E show the momentary proton beam position in the middle of the second slice, two-thirds of the way through a third slice, and after finalizing irradiation from a given direction, respectively. Using this approach, controlled, accurate, and precise delivery of proton irradiation energy to the tumor 1620, to a designated tumor subsection, or to a tumor layer is achieved. Efficiency of deposition of proton energy to tumor, as defined as the ratio of the proton irradiation energy delivered to the tumor relative to the proton irradiation energy delivered to the healthy tissue is further described infra.
Multi-field Irradiation
It is desirable to maximize efficiency of deposition of protons to the tumor 1620, as defined by maximizing the ratio of the proton irradiation energy delivered to the tumor 1620 relative to the proton irradiation energy delivered to the healthy tissue. Irradiation from one, two, or three directions into the body, such as by rotating the body about 90 degrees between irradiation sub-sessions results in proton irradiation from the distal portion of the Bragg peak concentrating into one, two, or three healthy tissue volumes, respectively. It is desirable to further distribute the distal portion of the Bragg peak energy evenly through the healthy volume tissue surrounding the tumor 1620.
Multi-field irradiation is proton beam irradiation from a plurality of entry points into the body. For example, the patient 1630 is rotated and the radiation source point is held constant. For example, the patient 1630 is rotated through 360 degrees and proton therapy is applied from a multitude of angles resulting in the distal radiation being circumferentially spread about the tumor yielding enhanced proton irradiation efficiency. In one case, the body is rotated into greater than 3, 5, 10, 15, 20, 25, 30, or 35 positions and proton irradiation occurs with each rotation position. Rotation of the patient is preferably performed using the patient positioning system 1610 and/or the bottom unit 1612 or disc, described supra. Rotation of the patient 1630 while keeping the delivery proton beam 268 in a relatively fixed orientation allows irradiation of the tumor 1620 from multiple directions without use of a new collimator for each direction. Further, as no new setup is required for each rotation position of the patient 1630, the system allows the tumor 1620 to be treated from multiple directions without reseating or positioning the patient, thereby minimizing tumor 1620 regeneration time, increasing the synchrotrons efficiency, and increasing patient throughput.
The patient is optionally centered on the bottom unit 1612 or the tumor 1620 is optionally centered on the bottom unit 1612. If the patient is centered on the bottom unit 1612, then the first axis control element 142 and second axis control element 144 are programmed to compensate for the off central axis of rotation position variation of the tumor 1620.
Referring now to FIGS. 19 A-E, an example of multi-field irradiation 1900 is presented. In this example, five patient rotation positions are illustrated; however, the five rotation positions are discrete rotation positions of about thirty-six rotation positions, where the body is rotated about ten degrees with each position. Referring now to FIG. 19A, a range of irradiation beam positions 269 is illustrated from a first body rotation position, illustrated as the patient 1630 facing the proton irradiation beam where a first healthy volume 1911 is irradiated by the ingress or distal portion of the Bragg peak energy irradiation profile. Referring now to FIG. 19B, the patient 1630 is rotated about forty degrees and the irradiation is repeated. In the second position, the tumor 1620 again receives the bulk of the irradiation energy and a second healthy tissue volume 1912 receives the smaller ingress or distal portion of the Bragg peak energy. Referring now to FIGS. 19 C-E, the patient 1630 is rotated a total of about 90, 130, and 180 degrees, respectively. For each of the third, fourth, and fifth rotation positions, the tumor 1620 receives the bulk of the irradiation energy and the third, fourth, and fifth healthy tissue volumes 1913, 1914, 1915 receive the smaller ingress or distal portion of the Bragg peak energy, respectively. Thus, the rotation of the patient during proton therapy results in the distribution of distal energy of the delivered proton energy to be distributed about the tumor 1620, such as to regions one to five 1911-1915, while along a given axis, at least about 75, 80, 85, 90, or 95 percent of the energy is delivered to the tumor 1620.
For a given rotation position, all or part of the tumor is irradiated. For example, in one embodiment only a distal section or distal slice of the tumor 1620 is irradiated with each rotation position, where the distal section is a section furthest from the entry point of the proton beam into the patient 1630. For example, the distal section is the dorsal side of the tumor when the patient 1630 is facing the proton beam and the distal section is the ventral side of the tumor when the patient 1630 is facing away from the proton beam.
Referring now to FIG. 20, a second example of multi-field irradiation 2000 is presented where the proton source is stationary and the patient 1630 is rotated. For ease of presentation, the stationary but scanning proton beam path 269 is illustrated as entering the patient 1630 from varying sides at times t1, t2, t3, . . . , tn, tn+1 as the patient is rotated. At a first time, t1, the distal end of the Bragg peak profile hits a first healthy tissue area 2010. The patient is rotated and the proton beam path is illustrated at a second time, t2, where the distal end of the Bragg peak hits a second healthy tissue area 2020. At a third time, the distal end of the Bragg peak profile hits a third healthy tissue area 2030. This rotation and irradiation process is repeated n times, where n is a positive number greater than four and preferably greater than about 10, 20, 30, 100, or 300. As illustrated, at an nth time when an nth healthy tissue area 2040 is irradiated, if the patient 1630 is rotated further, the scanning proton beam 269 would hit a sensitive body constituent 1650, such as the spinal cord or eyes. Irradiation is preferably suspended until the sensitive body constituent is rotated out of the scanning proton beam 269 path. Irradiation is resumed at a time, tn+1, after the sensitive body constituent 1650 is rotated our of the proton beam path and a nth+1 healthy tissue area 2050 is irradiated. In this manner, the Bragg peak energy is always within the tumor, the distal region of the Bragg peak profile is distributed in healthy tissue about the tumor 1620, and sensitive body constituents 1650 receive minimal or no proton beam irradiation.
In one multi-field irradiation example, the particle therapy system with a synchrotron ring diameter of less than six meters includes ability to:

    
    
        rotate the patient through about 360 degrees;
        extract radiation in about 0.1 to 10 seconds;
        scan vertically about 100 millimeters;
        scan horizontally about 700 millimeters;
        vary beam energy from about 30 to 330 MeV/second during irradiation;
        vary the proton beam intensity independently of varying the proton beam energy;
        focus the proton beam from about 2 to 20 millimeters at the tumor; and/or
        complete multi-field irradiation of a tumor in less than about 1, 2, 4, or 6 minutes as measured from the time of initiating proton delivery to the patient 1630.
    
    


Referring now to FIG. 21, two multi-field irradiation methods 2100 are described. In the first method, the main controller 110 rotationally positions 2110 the patient 1630 and subsequently irradiates 2120 the tumor 1620. The process is repeated until a multi-field irradiation plan is complete. In the second method, the main controller 110 simultaneously rotates and irradiates 2130 the tumor 1620 within the patient 1630 until the multi-field irradiation plan is complete. More particularly, the proton beam irradiation occurs while the patient 1630 is being rotated.
The 3-dimensional scanning system of the proton spot focal point, described herein, is preferably combined with a rotation/raster method. The method includes layer wise tumor irradiation from many directions. During a given irradiation slice, the proton beam energy is continuously changed according to the tissue's density in front of the tumor to result in the beam stopping point, defined by the Bragg peak, always being inside the tumor and inside the irradiated slice. The novel method allows for irradiation from many directions, referred to herein as multi-field irradiation, to achieve the maximal effective dose at the tumor level while simultaneously significantly reducing possible side-effects on the surrounding healthy tissues in comparison to existing methods. Essentially, the multi-field irradiation system distributes dose-distribution at tissue depths not yet reaching the tumor.
Proton Beam Position Control
Presently, the worldwide radiotherapy community uses a method of dose field forming using a pencil beam scanning system. In stark contrast, an optional spot scanning system or tissue volume scanning system is used. In the tissue volume scanning system, the proton beam is controlled, in terms of transportation and distribution, using an inexpensive and precise scanning system. The scanning system is an active system, where the beam is focused into a spot focal point of about one-half, one, two, or three millimeters in diameter. The focal point is translated along two axes while simultaneously altering the applied energy of the proton beam, which effectively changes the third dimension of the focal point. The system is applicable in combination with the above described rotation of the body, which preferably occurs in-between individual moments or cycles of proton delivery to the tumor. Optionally, the rotation of the body by the above described system occurs continuously and simultaneously with proton delivery to the tumor.
For example, the spot is translated horizontally, is moved down a vertical y-axis, and is then back along the horizontal axis. In this example, current is used to control a vertical scanning system having at least one magnet. The applied current alters the magnetic field of the vertical scanning system to control the vertical deflection of the proton beam. Similarly, a horizontal scanning magnet system controls the horizontal deflection of the proton beam. The degree of transport along each axes is controlled to conform to the tumor cross-section at the given depth. The depth is controlled by changing the energy of the proton beam. For example, the proton beam energy is decreased, so as to define a new penetration depth, and the scanning process is repeated along the horizontal and vertical axes covering a new cross-sectional area of the tumor. Combined, the three axes of control allow scanning or movement of the proton beam focal point over the entire volume of the cancerous tumor. The time at each spot and the direction into the body for each spot is controlled to yield the desired radiation does at each sub-volume of the cancerous volume while distributing energy hitting outside of the tumor.
The focused beam spot volume dimension is preferably tightly controlled to a diameter of about 0.5, 1, or 2 millimeters, but is alternatively several centimeters in diameter. Preferred design controls allow scanning in two directions with: (1) a vertical amplitude of about 100 mm amplitude and frequency up to about 200 Hz; and (2) a horizontal amplitude of about 700 mm amplitude and frequency up to about 1 Hz.
The distance the protons move along the z-axis into the tissue, in this example, is controlled by the kinetic energy of the proton. This coordinate system is arbitrary and exemplary. The actual control of the proton beam is controlled in 3-dimensional space using two scanning magnet systems and by controlling the kinetic energy of the proton beam. Particularly, the system allows simultaneous adjustment of the x-, y-, and z-axes in the irradiation of the solid tumor. Stated again, instead of scanning along an x,y-plane and then adjusting energy of the protons, such as with a range modulation wheel, the system allows for moving along the z-axes while simultaneously adjusting the x- and or y-axes. Hence, rather than irradiating slices of the tumor, the tumor is optionally irradiated in three simultaneous dimensions. For example, the tumor is irradiated around an outer edge of the tumor in three dimensions. Then the tumor is irradiated around an outer edge of an internal section of the tumor. This process is repeated until the entire tumor is irradiated. The outer edge irradiation is preferably coupled with simultaneous rotation of the subject, such as about a vertical y-axis. This system allows for maximum efficiency of deposition of protons to the tumor, as defined as the ratio of the proton irradiation energy delivered to the tumor relative to the proton irradiation energy delivered to the healthy tissue.
Combined, the system allows for multi-axes control of the charged particle beam system in a small space with low power supply. For example, the system uses multiple magnets where each magnet has at least one edge focusing effect in each turning section of the synchrotron. The multiple edge focusing effects in the circulating beam path of the synchrotron yields a synchrotron having:

    
    
        a small circumference system, such as less than about 50 meters;
        a vertical proton beam size gap of about 2 cm;
        corresponding reduced power supply requirements associated with the reduced gap size; and
        control of z-axis energy.
    
    


The result is a 3-dimensional scanning system, x-, y-, and z-axes control, where the z-axes control resides in the synchrotron and where the z-axes energy is variably controlled during the extraction process inside the synchrotron.
An example of a proton scanning or targeting system 140 used to direct the protons to the tumor with 3-dimensional scanning control is provided, where the 3-dimensional scanning control is along the x-, y-, and z-axes, as described supra. A fourth controllable axis is time. A fifth controllable axis is patient rotation. Combined with rotation of the subject about a vertical axis, a multi-field illumination process is used where a not yet irradiated portion of the tumor is preferably irradiated at the further distance of the tumor from the proton entry point into the body. This yields the greatest percentage of the proton delivery, as defined by the Bragg peak, into the tumor and minimizes damage to peripheral healthy tissue.
Imaging/X-Ray System
Herein, an X-ray system is used to illustrate an imaging system.
Timing
An X-ray is preferably collected either (1) just before or (2) concurrently with treating a subject with proton therapy for a couple of reasons. First, movement of the body, described supra, changes the local position of the tumor in the body relative to other body constituents. If the patient or subject 1630 has an X-ray taken and is then bodily moved to a proton treatment room, accurate alignment of the proton beam to the tumor is problematic. Alignment of the proton beam to the tumor 1620 using one or more X-rays is best performed at the time of proton delivery or in the seconds or minutes immediately prior to proton delivery and after the patient is placed into a therapeutic body position, which is typically a fixed position or partially immobilized position. Second, the X-ray taken after positioning the patient is used for verification of proton beam alignment to a targeted position, such as a tumor and/or internal organ position.
Patient Immobilization
Accurate and precise delivery of a proton beam to a tumor of a patient requires: (1) positioning control of the proton beam and (2) positioning control of the patient. As described, supra, the proton beam is controlled using algorithms and magnetic fields to a diameter of about 0.5, 1, or 2 millimeters. This section addresses partial immobilization, restraint, and/or alignment of the patient to insure the tightly controlled proton beam efficiently hits a target tumor and not surrounding healthy tissue as a result of patient movement.
Herein, an x-, y-, and z-axes coordinate system and rotation axis is used to describe the orientation of the patient relative to the proton beam. The z-axis represent travel of the proton beam, such as the depth of the proton beam into the patient. When looking at the patient down the z-axis of travel of the proton beam, the x-axis refers to moving left or right across the patient and the y-axis refers to movement up or down the patient. A first rotation axis is rotation of the patient about the y-axis and is referred to herein as a rotation axis, bottom unit 1612 rotation axis, or y-axis of rotation 1617. In addition, tilt is rotation about the x-axis, yaw is rotation about the y-axis, and roll is rotation about the z-axis. In this coordinate system, the proton beam path 269 optionally runs in any direction. As an illustrative matter, the proton beam path running through a treatment room is described as running horizontally through the treatment room.
In this section, three examples of positioning systems are provided: (1) a semi-vertical partial immobilization system 2200; (2) a sitting partial immobilization system 2300; and (3) a laying position 2400. Elements described for one immobilization system apply to other immobilization systems with small changes. For example, a headrest, a head support, or head restraint will adjust along one axis for a reclined position, along a second axis for a seated position, and along a third axis for a laying position. However, the headrest itself is similar for each immobilization position.
Vertical Patient Positioning/Immobilization
Referring now to FIG. 22, the semi-vertical patient positioning system 2200 is preferably used in conjunction with proton therapy of tumors in the torso. The patient positioning and/or immobilization system controls and/or restricts movement of the patient during proton beam therapy. In a first partial immobilization embodiment, the patient is positioned in a semi-vertical position in a proton beam therapy system. As illustrated, the patient is reclining at an angle alpha, a, about 45 degrees off of the y-axis as defined by an axis running from head to foot of the patient. More generally, the patient is optionally completely standing in a vertical position of zero degrees off the of y-axis or is in a semi-vertical position alpha that is reclined about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, or 65 degrees off of the y-axis toward the z-axis.
Patient positioning constraints 2215 that are used to maintain the patient in a treatment position, include one or more of: a seat support 2220, a back support 2230, a head support 2240, an arm support 2250, a knee support 2260, and a foot support 2270. The constraints are optionally and independently rigid or semi-rigid. Examples of a semi-rigid material include a high or low density foam or a visco-elastic foam. For example the foot support is preferably rigid and the back support is preferably semi-rigid, such as a high density foam material. One or more of the positioning constraints 2215 are movable and/or under computer control for rapid positioning and/or immobilization of the patient. For example, the seat support 2220 is adjustable along a seat adjustment axis 2222, which is preferably the y-axis; the back support 2230 is adjustable along a back support axis 2232, which is preferably dominated by z-axis movement with a y-axis element; the head support 2240 is adjustable along a head support axis 2242, which is preferably dominated by z-axis movement with a y-axis element; the arm support 2250 is adjustable along an arm support axis 2252, which is preferably dominated by z-axis movement with a y-axis element; the knee support 2260 is adjustable along a knee support axis 2262, which is preferably dominated by z-axis movement with a y-axis element; and the foot support 2270 is adjustable along a foot support axis 2272, which is preferably dominated by y-axis movement with a z-axis element.
If the patient is not facing the incoming proton beam, then the description of movements of support elements along the axes change, but the immobilization elements are the same.
An optional camera 2280 is used with the patient immobilization system. The camera views the patient/subject 1630 creating a video image. The image is provided to one or more operators of the charged particle beam system and allows the operators a safety mechanism for determining if the subject has moved or desires to terminate the proton therapy treatment procedure. Based on the video image, the operators may suspend or terminate the proton therapy procedure. For example, if the operator observes via the video image that the subject is moving, then the operator has the option to terminate or suspend the proton therapy procedure.
An optional video display or display monitor 2290 is provided to the patient. The video display optionally presents to the patient any of: operator instructions, system instructions, status of treatment, or entertainment.
Motors for positioning the patient positioning constraints 2215, the camera 2280, and/or video display 2290 are preferably mounted above or below the proton transport path 268 or momentary proton scanning path 269.
Breath control is optionally performed by using the video display. As the patient breathes, internal and external structures of the body move in both absolute terms and in relative terms. For example, the outside of the chest cavity and internal organs both have absolute moves with a breath. In addition, the relative position of an internal organ relative to another body component, such as an outer region of the body, a bone, support structure, or another organ, moves with each breath. Hence, for more accurate and precise tumor targeting, the proton beam is preferably delivered at a point in time where the position of the internal structure or tumor is well defined, such as at the bottom or top of each breath. The video display is used to help coordinate the proton beam delivery with the patient's breathing cycle. For example, the video display optionally displays to the patient a command, such as a hold breath statement, a breathe statement, a countdown indicating when a breath will next need to be held, or a countdown until breathing may resume.
Sitting Patient Positioning/Immobilization
In a second partial immobilization embodiment, the patient is partially restrained in a seated position 2300. The sitting restraint system uses support structures similar to the support structures in the semi-vertical positioning system, described supra, with an exception that the seat support is replaced by a chair and the knee support is not required. The seated restraint system generally retains the adjustable support, rotation about the y-axis, camera, video, and breadth control parameters described in the semi-vertical embodiment, described supra.
Referring now to FIG. 23, a particular example of a sitting patient semi-immobilization system 2300 is provided. The sitting system is preferably used for treatment of head and/or neck tumors. As illustrated, the patient is positioned in a seated position on a chair 2310 for particle therapy. The patient is further immobilized using any of the: the head support 2240, the back support 2230, the hand support 2250, the knee support 2260, and the foot support 2270. The supports 2220, 2230, 2240, 2250, 2260, 2270 preferably have respective axes of adjustment 2222, 2232, 2242, 2252, 2262, 2272 as illustrated. The chair 2310 is either readily removed to allow for use of a different patient constraint system or adapts under computer control to a new patient position, such as the semi-vertical system.
Laying Patient Positioning/Immobilization
In a third partial immobilization embodiment, the patient is partially restrained in a laying position. The laying restraint system 2400 has support structures that are similar to the support structures used in the sitting positioning system 2300 and semi-vertical positioning system 2200, described supra. In the laying position, optional restraint, support, or partial immobilization elements include one or more of: the head support 2240 and the back support, hip, and shoulder 2230 support. The supports preferably have respective axes of adjustment that are rotated as appropriate for a laying position of the patient. The laying position restraint system generally retains the adjustable supports, rotation about the y-axis, camera, video, and breadth control parameters described in the semi-vertical embodiment, described supra.
Referring now to FIG. 24, if the patient is very sick, such as the patient has trouble standing for a period of about one to three minutes required for treatment, then being in a partially supported system can result in some movement of the patient due to muscle strain. In this and similar situations, treatment of a patient in a laying position on a support table 2420 is preferentially used. The support table has a horizontal platform to support the bulk of the weight of the patient. Preferably, the horizontal platform is detachable from a treatment platform. In a laying positioning system 2400, the patient is positioned on a platform 2410, which has a substantially horizontal portion for supporting the weight of the body in a horizontal position. Optional hand grips are used, described infra. In one embodiment, the platform 2410 affixes relative to the table 2420 using a mechanical stop or lock element 2430 and matching key element 2435 and/or the patient 1630 is aligned or positioned relative to a placement element 2460.
Additionally, upper leg support 2444, lower leg support 2440, and/or arm support 2450 elements are optionally added to raise, respectively, an arm or leg out of the proton beam path 269 for treatment of a tumor in the torso or to move an arm or leg into the proton beam path 269 for treatment of a tumor in the arm or leg. This increases proton delivery efficiency, as described supra. The leg supports 2440, 2444 and arm support 2450 are each optionally adjustable along support axes or arcs 2442, 2446, 2452. One or more leg support elements are optionally adjustable along an arc to position the leg into the proton beam path 269 or to remove the leg from the proton beam path 269, as described infra. An arm support element is preferably adjustable along at least one arm adjustment axis or along an arc to position the arm into the proton beam path 269 or to remove the arm from the proton beam path 269, as described infra.
Preferably, the patient is positioned on the platform 2410 in an area or room outside of the proton beam path 268 and is wheeled or slid into the treatment room or proton beam path area. For example, the patient is wheeled into the treatment room on a gurney where the top of the gurney, which is the platform, detaches and is positioned onto a table. The platform is preferably slid onto the table so that the gurney or bed need not be lifted onto the table.
The semi-vertical patient positioning system 2200 and sitting patient positioning system 2300 are preferentially used to treatment of tumors in the head or torso due to efficiency. The semi-vertical patient positioning system 2200, sitting patient positioning system 2300, and laying patient positioning system 2400 are all usable for treatment of tumors in the patient's limbs.
Support System Elements
Positioning constraints 2215 include all elements used to position the patient, such as those described in the semi-vertical positioning system 2200, sitting positioning system 2300, and laying positioning system 2400. Preferably, positioning constraints or support system elements are aligned in positions that do not impede or overlap the proton beam path 269. However, in some instances the positioning constraints are in the proton beam path 269 during at least part of the time of treatment of the patient. For instance, a positioning constraint element may reside in the proton beam path 269 during part of a time period where the patient is rotated about the y-axis during treatment. In cases or time periods that the positioning constraints or support system elements are in the proton beam path, then an upward adjustment of proton beam energy is preferably applied that increases the proton beam energy to offset the positioning constraint element impedance of the proton beam. In one case, the proton beam energy is increased by a separate measure of the positioning constraint element impedance determined during a reference scan of the positioning constraint system element or set of reference scans of the positioning constraint element as a function of rotation about the y-axis.
For clarity, the positioning constraints 2215 or support system elements are herein described relative to the semi-vertical positioning system 2200; however, the positioning elements and descriptive x-, y-, and z-axes are adjustable to fit any coordinate system, to the sitting positioning system 2300, or the laying positioning system 2400.
An example of a head support system is described to support, align, and/or restrict movement of a human head. The head support system preferably has several head support elements including any of: a back of head support, a right of head alignment element, and a left of head alignment element. The back of head support element is preferably curved to fit the head and is optionally adjustable along a head support axis, such as along the z-axis. Further, the head supports, like the other patient positioning constraints, is preferably made of a semi-rigid material, such as a low or high density foam, and has an optional covering, such as a plastic or leather. The right of head alignment element and left of head alignment elements or head alignment elements, are primarily used to semi-constrain movement of the head or to fully immobilize the head. The head alignment elements are preferably padded and flat, but optionally have a radius of curvature to fit the side of the head. The right and left head alignment elements are preferably respectively movable along translation axes to make contact with the sides of the head. Restricted movement of the head during proton therapy is important when targeting and treating tumors in the head or neck. The head alignment elements and the back of head support element combine to restrict tilt, rotation or yaw, roll and/or position of the head in the x-, y-, z-axes coordinate system.
Referring now to FIG. 25 another example of a head support system 2500 is described for positioning and/or restricting movement of a human head 1602 during proton therapy of a solid tumor in the head or neck. In this system, the head is restrained using 1, 2, 3, 4, or more straps or belts, which are preferably connected or replaceably connected to a back of head support element 2510. In the example illustrated, a first strap 2520 pulls or positions the forehead to the head support element 2510, such as by running predominantly along the z-axis. Preferably a second strap 2530 works in conjunction with the first strap 2520 to prevent the head from undergoing tilt, yaw, roll or moving in terms of translational movement on the x-, y-, and z-axes coordinate system. The second strap 2530 is preferably attached or replaceable attached to the first strap 2520 at or about: (1) the forehead 2532; (2) on one or both sides of the head 2534; and/or (3) at or about the support element 2510. A third strap 2540 preferably orientates the chin of the subject relative to the support element 2510 by running dominantly along the z-axis. A fourth strap 2550 preferably runs along a predominantly y- and z-axes to hold the chin relative to the head support element 2510 and/or proton beam path. The third 2540 strap preferably is attached to or is replaceably attached to the fourth strap 2550 during use at or about the patient's chin 2542. The second strap 2530 optionally connects 2536 to the fourth strap 2550 at or about the support element 2510. The four straps 2520, 2530, 2540, 2550 are illustrative in pathway and interconnection. Any of the straps optionally hold the head along different paths around the head and connect to each other in separate fashion. Naturally, a given strap preferably runs around the head and not just on one side of the head. Any of the straps 2520, 2530, 2540, and 2550 are optionally used independently or in combinations and permutations with the other straps. The straps are optionally indirectly connected to each other via a support element, such as the head support element 2510. The straps are optionally attached to the head support element 2510 using hook and loop technology, a buckle, or fastener. Generally, the straps combine to control position, front-to-back movement of the head, side-to-side movement of the head, tilt, yaw, roll, and/or translational position of the head.
The straps are preferably of known impedence to proton transmission allowing a calculation of peak energy release along the z-axis to be calculated. For example, adjustment to the Bragg peak energy is made based on the slowing tendency of the straps to proton transport.
Referring now to FIG. 26, still another example of a head support system 2240 is described. The head support 2240 is preferably curved to fit a standard or child sized head. The head support 2240 is optionally adjustable along a head support axis 2242. Further, the head supports, like the other patient positioning constraints, is preferably made of a semi-rigid material, such as a low or high density foam, and has an optional covering, such as a plastic or leather.
Elements of the above described head support, head positioning, and head immobilization systems are optionally used separately or in combination.
Still referring to FIG. 26, an example of the arm support 2250 is further described. The arm support preferably has a left hand grip 2610 and a right hand grip 2620 used for aligning the upper body of the patient 1630 through the action of the patient 1630 gripping the left and right hand grips 2610, 2620 with the patient's hands 1634. The left and right hand grips 2610, 2620 are preferably connected to the arm support 2250 that supports the mass of the patient's arms. The left and right hand grips 2610, 2620 are preferably constructed using a semi-rigid material. The left and right hand grips 2610, 2620 are optionally molded to the patient's hands to aid in alignment. The left and right hand grips optionally have electrodes, as described supra.
An example of the back support is further described. The back support is preferably curved to support the patient's back and to wrap onto the sides of the patient's torso. The back support preferably has two semi-rigid portions, a left side and right side. Further, the back support has a top end and a bottom end. A first distance between the top ends of the left side and right side is preferably adjustable to fit the upper portion of the patient's back. A second distance between the bottom ends of the left side and right side is preferably independently adjustable to fit the lower portion of the patient's back.
An example of the knee support is further described. The knee support preferably has a left knee support and a right knee support that are optionally connected or individually movable. Both the left and right knee supports are preferably curved to fit standard sized knees. The left knee support is optionally adjustable along a left knee support axis and the right knee support is optionally adjustable along a right knee support axis. Alternatively, the left and right knee supports are connected and movable along the knee support axis. Both the left and right knee supports, like the other patient positioning constraints, are preferably made of a semi-rigid material, such as a low or high density foam, having an optional covering, such as a plastic or leather.
Patient Breathing Monitoring
Preferably, the patient's breathing pattern is monitored. When a subject or patient 1630 is breathing many portions of the body move with each breath. For example, when a subject breathes the lungs move as do relative positions of organs within the body, such as the stomach, kidneys, liver, chest muscles, skin, heart, and lungs. Generally, most or all parts of the torso move with each breath. Indeed, the inventors have recognized that in addition to motion of the torso with each breath, various motion also exists in the head and limbs with each breath. Motion is to be considered in delivery of a proton dose to the body as the protons are preferentially delivered to the tumor and not to surrounding tissue. Motion thus results in an ambiguity in where the tumor resides relative to the beam path. To partially overcome this concern, protons are preferentially delivered at the same point in each of a series of breathing cycles.
Initially a rhythmic pattern of breathing of a subject is determined. The cycle is observed or measured. For example, an X-ray beam operator or proton beam operator can observe when a subject is breathing or is between breaths and can time the delivery of the protons to a given period of each breath. Alternatively, the subject is told to inhale, exhale, and/or hold their breath and the protons are delivered during the commanded time period.
Preferably, one or more sensors are used to determine the breathing cycle of the individual. Two examples of a respiration monitoring system are provided: (1) a thermal monitoring system and (2) a force monitoring system.
Referring again to FIG. 25, a first example of the thermal breath monitoring system is provided. In the thermal breath monitoring system, a sensor is placed by the nose and/or mouth of the patient. As the jaw of the patient is optionally constrained, as described supra, the thermal breath monitoring system is preferably placed by the patient's nose exhalation path. To avoid steric interference of the thermal sensor system components with proton therapy, the thermal breath monitoring system is preferably used when treating a tumor not located in the head or neck, such as a when treating a tumor in the torso or limbs. In the thermal monitoring system, a first thermal resistor 2570 is used to monitor the patient's breathing cycle and/or location in the patient's breathing cycle. Preferably, the first thermal resistor 2570 is placed by the patient's nose, such that the patient exhaling through their nose onto the first thermal resistor 2570 warms the first thermal resistor 2570 indicating an exhale. Preferably, a second thermal resistor 2560 operates as an environmental temperature sensor. The second thermal resistor 2560 is preferably placed out of the exhalation path of the patient but in the same local room environment as the first thermal resistor 2570. Generated signal, such as current from the thermal resistors 2570, 2560, is preferably converted to voltage and communicated with the main controller 110 or a sub-controller of the main controller. Preferably, the second thermal resistor 2560 is used to adjust for the environmental temperature fluctuation that is part of a signal of the first thermal resistor 2570, such as by calculating a difference between the values of the thermal resistors 2570, 2560 to yield a more accurate reading of the patient's breathing cycle.
Referring again to FIG. 23, a second example of a monitoring system is provided. In an example of a force breath monitoring system, a sensor is placed by the torso. For instance, the force meter is replaceably attached to the patient's chest. To avoid steric interference of the force sensor system components with proton therapy, the force breath monitoring system is preferably used when treating a tumor located in the head, neck, or limbs. In the force monitoring system, a belt or strap 2350 is placed around an area of the patient's torso that expands and contracts with each breath cycle of the patient. The belt 2350 is preferably tight about the patient's chest and is flexible. A force meter 2352 is attached to the belt and senses the patients breathing pattern. The forces applied to the force meter 2352 correlate with periods of the breathing cycle. The signals from the force meter 2352 are preferably communicated with the main controller 110 or a sub-controller of the main controller.
Respiration Control
In one embodiment, a patient is positioned and once the rhythmic pattern of the subject's breathing or respiration cycle is determined, a signal is optionally delivered to the patient, such as via the display monitor 2290, to more precisely control the breathing frequency. For example, the display screen 2290 is placed in front of the patient and a message or signal is transmitted to the display screen 2290 directing the subject when to hold their breath and when to breathe. Typically, a respiration control module uses input from one or more of the breathing sensors. For example, the input is used to determine when the next breath exhale is to complete. At the bottom of the breath, the control module displays a hold breath signal to the subject, such as on a monitor, via an oral signal, digitized and automatically generated voice command, or via a visual control signal. Preferably, a display monitor 2290 is positioned in front of the subject and the display monitor displays breathing commands to the subject. Typically, the subject is directed to hold their breath for a short period of time, such as about 1⁄2, 1, 2, 3, 5, or 10 seconds. The period of time the breath is held is preferably synchronized to the delivery time of the proton beam to the tumor, which is about 1⁄2, 1, 2, or 3 seconds. While delivery of the protons at the bottom of the breath is preferred, protons are optionally delivered at any point in the breathing cycle, such as upon full inhalation. Delivery at the top of the breath or when the patient is directed to inhale deeply and hold their breath by the breathing control module is optionally performed as at the top of the breath the chest cavity is largest and for some tumors the distance between the tumor and surrounding tissue is maximized or the surrounding tissue is rarefied as a result of the increased volume. Hence, protons hitting surrounding tissue is minimized. Optionally, the display screen tells the subject when they are about to be asked to hold their breath, such as with a 3, 2, 1, second countdown so that the subject is aware of the task they are about to be asked to perform.
Proton Beam Therapy Synchronization with Respiration
In one embodiment, charged particle therapy and preferably multi-field proton therapy is coordinated and synchronized with patient respiration via use of the respiration feedback sensors, described supra, used to monitor and/or control patient respiration. Preferably, the charged particle therapy is performed on a patient in a partially immobilized and repositionable position and the proton delivery to the tumor 1620 is timed to patient respiration via control of charged particle beam injection, acceleration, extraction, and/or targeting methods and apparatus. The synchronization enhances proton delivery accuracy by removing position ambiguity due to the relative movement of body constituents during a patient breathing cycle.
In a second embodiment, an X-ray system is used to provide X-ray images of a patient in the same orientation as viewed by a proton therapy beam and both the X-ray system and the proton therapy beam are synchronized with patient respiration. Preferably, the synchronized system is used in conjunction with the negative ion beam source, synchrotron, and/or targeting method and apparatus to provide an X-ray timed with patient breathing where the X-ray is collected immediately prior to and/or concurrently with particle beam therapy irradiation to ensure targeted and controlled delivery of energy relative to a patient position resulting in efficient, precise, and/or accurate treatment of a solid cancerous tumor with minimization of damage to surrounding healthy tissue in a patient using the proton beam position verification system.
A proton delivery control algorithm is used to synchronize delivery of the protons to the tumor within a given period of each breath, such as at the top of a breath, at the bottom of a breath, and/or when the subject is holding their breath. The proton delivery control algorithm is preferably integrated with the breathing control module. Thus, the proton delivery control algorithm knows when the subject is breathing, where in the respiration cycle the subject is, and/or when the subject is holding their breath. The proton delivery control algorithm controls when protons are injected and/or inflected into the synchrotron, when an RF signal is applied to induce an oscillation, as described supra, and when a DC voltage is applied to extract protons from the synchrotron, as described supra. Typically, the proton delivery control algorithm initiates proton inflection and subsequent RF induced oscillation before the subject is directed to hold their breath or before the identified period of the breathing cycle selected for a proton delivery time. In this manner, the proton delivery control algorithm delivers protons at a selected period of the breathing cycle. The proton delivery control algorithm is optionally set to an AC RF signal that matches the breathing cycle or directed breathing cycle of the subject.
The above described charged particle therapy elements are combined in combinations and/or permutations in developing and implementing a tumor treatment plan, described infra.
Computer Controlled Patient Repositioning
One or more of the patient positioning unit components and/or one of more of the patient positioning constraints are preferably under computer control. For example, the computer records or controls the position of the patient positioning elements 2215, such as via recording a series of motor positions connected to drives that move the patient positioning elements 2215. For example, the patient is initially positioned and constrained by the patient positioning constraints 2215. The position of each of the patient positioning constraints is recorded and saved by the main controller 110, by a sub-controller of the main controller 110, or by a separate computer controller. Then, imaging systems are used to locate the tumor 1620 in the patient 1630 while the patient is in the controlled position of final treatment. Preferably, when the patient is in the controlled position, multi-field imaging is performed, as described herein. The imaging system 170 includes one or more of: MRI's, X-rays, CT's, proton beam tomography, and the like. Time optionally passes at this point while images from the imaging system 170 are analyzed and a proton therapy treatment plan is devised. The patient optionally exits the constraint system during this time period, which may be minutes, hours, or days. Upon, and preferably after, return of the patient and initial patient placement into the patient positioning unit, the computer returns the patient positioning constraints to the recorded positions. This system allows for rapid repositioning of the patient to the position used during imaging and development of the multi-field charged particle irradiation treatment plan, which minimizes setup time of patient positioning and maximizes time that the charged particle beam system 100 is used for cancer treatment.
Reproducing Patient Positioning and Immobilization
In one embodiment, using a patient positioning and immobilization system, a region of the patient 1630 about the tumor 1620 is reproducibly positioned and immobilized, such as with the motorized patient translation and rotation positioning system 1610 and/or with the patient positioning constraints 2215. For example, one of the above described positioning systems, such as (1) the semi-vertical partial immobilization system 2200; (2) the sitting partial immobilization system 2300; or (3) the laying position system 2400 is used in combination with the patient translation and rotation system 1610 to position the tumor 1620 of the patient 1630 relative to the proton beam path 268. Preferably, the position and immobilization system controls position of the tumor 1620 relative to the proton beam path 268, immobilizes position of the tumor 1620, and facilitates repositioning the tumor 1620 relative to the proton beam path 268 after the patient 1630 has moved away from the proton beam path 268, such as during development of an irradiation treatment plan.
Preferably, the tumor 1620 of the patient 1630 is positioned in terms of 3-D location and in terms of orientation attitude. Herein, 3-D location is defined in terms of the x-, y-, and z-axes and orientation attitude is the state of pitch, yaw, and roll. Roll is rotation of a plane about the z-axis, pitch is rotation of a plane about the x-axis, and yaw is the rotation of a plane about the y-axis. Tilt is used to describe both roll and pitch. Preferably, the positioning and immobilization system controls the tumor 1620 location relative to the proton beam path 268 in terms of at least three of and preferably in terms of four, five, or six of: pitch, yaw, roll, x-axis location, y-axis location, and z-axis location.
Chair
The patient positioning and immobilization system is further described using a chair positioning example. For clarity, a case of positioning and immobilizing a tumor in a shoulder is described using chair positioning. Using the semi-vertical immobilization system 2200, the patient is generally positioned using the seat support 2220, knee support 2260, and/or foot support 2270. To further position the shoulder, a motor in the back support 2230 pushes against the torso of the patient. Additional arm support 2250 motors align the arm, such as by pushing with a first force in one direction against the elbow of the patient and the wrist of the patient is positioned using a second force in a counter direction. This restricts movement of the arm, which helps to position the shoulder. Optionally, the head support is positioned to further restrict movement of the shoulder by applying tension to the neck. Combined, the patient positioning constraints 2215 control position of the tumor 1620 of the patient 1630 in at least three dimensions and preferably control position of the tumor 1620 in terms of all of yaw, roll, and pitch movement as well as in terms of x-, y-, and z-axis position. For instance, the patient positioning constraints position the tumor 1620 and restricts movement of the tumor, such as by preventing patient slumping. Optionally, sensors in one or more of the patient positioning constraints 2215 record an applied force. In one case, the seat support senses weight and applies a force to support a fraction of the patient's weight, such as about 50, 60, 70, or 80 percent of the patient's weight. In a second case, a force applied to the neck, arm, and/or leg is recorded.
Generally, the patient positioning and immobilization system removes movement degrees of freedom from the patient 1630 to accurately and precisely position and control the position of the tumor 1620 relative to the X-ray beam path, proton beam path 268, and/or an imaging beam path. Further, once the degrees of freedom are removed, the motor positions for each of the patient positioning constraints are recorded and communicated digitally to the main controller 110. Once the patient moves from the immobilization system, such as when the irradiation treatment plan is generated, the patient 1630 must be accurately repositioned before the irradiation plan is implemented. To accomplish this, the patient 1630 sits generally in the positioning device, such as the chair, and the main controller sends the motor position signals and optionally the applied forces back to motors controlling each of the patient positioning constraints 2215 and each of the patient positioning constraints 2215 are automatically moved back to their respective recorded positions. Hence, re-positioning and re-immobilizing the patient 1630 is accomplished from a time of sitting to fully controlled position in less than about 10, 30, 60, or 120 seconds.
Using the computer controlled and automated patient positioning system, the patient is re-positioned in the positioning and immobilization system using the recalled patient positioning constraint 2215 motor positions; the patient 1630 is translated and rotated using the patient translation and rotation system 1620 relative to the proton beam 268; and the proton beam 268 is scanned to its momentary beam position 269 by the main controller 110, which follows the generated irradiation treatment plan.
Although the invention has been described herein with reference to certain preferred embodiments, one skilled in the art will readily appreciate that other applications may be substituted for those set forth herein without departing from the spirit and scope of the present invention.

## Claims

1. An apparatus for generating a negative ion beam for use with charged particle radiation therapy, comprising:
a negative ion source comprising:
a magnetic material; and
a high temperature plasma chamber substantially encompassing said magnetic material;
wherein said high temperature plasma chamber comprises: a first ion generation electrode at a first end of said high temperature plasma chamber, a second ion generation electrode at a second end of said high temperature plasma chamber, and a magnetic field carrying outer wall;
wherein application of a first high voltage pulse across said first ion generation electrode and said second ion generation electrode breaks hydrogen in said high temperature plasma chamber into component parts;
wherein said magnetic material yields a magnetic field loop running through said first ion generation electrode, through said magnetic field carrying outer wall, through said second ion generation electrode, across a gap, and through said magnetic material;
wherein said magnetic field loop yields a magnetic barrier across said gap between said high temperature plasma chamber and a low temperature plasma region, said magnetic barrier passing a subset of said component parts;
wherein low energy electrons interact with atomic hydrogen to create hydrogen anions in said low temperature plasma region;
wherein application of a second high voltage pulse across said second ion generation electrode and a third ion generation electrode extracts negative ions from said negative ion source into a negative ion beam.

2. The apparatus of claim 1, wherein said first high voltage pulse comprises a pulse of at least four kilovolts for a period of at least fifteen microseconds.

3. The apparatus of claim 2, wherein said second high voltage pulse comprises a pulse of at least twenty kilovolts during a period overlapping the last five microseconds of said first high voltage pulse.

4. The apparatus of claim 2, wherein said second high voltage pulse comprises a pulse of at least twenty kilovolts during a period overlapping at least three microseconds of said first high voltage pulse.

5. The apparatus of claim 1, further comprising a negative ion beam focusing system, comprising:
a first focusing electrode circumferentially surrounding the negative ion beam;
a second focusing electrode comprising conductive paths at least partially blocking the negative ion beam;
wherein electric field lines run between said first focusing electrode and said second focusing electrode,
wherein the negative ions in the negative ion beam encounter force vectors running up said first electric field lines that focus the negative ion beam.

6. The apparatus of claim 5, wherein said first focusing electrode comprises a negative charge, wherein said second focusing electrode comprises a positive charge.

7. The apparatus of claim 6, wherein said conductive paths comprise any of:
a series of conductive lines running substantially in parallel across the negative ion beam;
a conductive grid crossing the negative ion beam; and
a foil crossing the negative ion beam, said foil having holes with combined areas of at least ninety percent of the cross-sectional area of the negative ion beam.

8. The apparatus of claim 7, wherein said conductive paths block less than ten percent of the cross-sectional area of the negative ion beam.

9. The apparatus of claim 1, further comprising:
a synchrotron, comprising:
four turning sections, wherein each of said turning sections turns said charged particle beam about ninety degrees;

wherein the negative ion beam is converted into a proton beam;
wherein the proton beam is injected into said synchrotron;
wherein said synchrotron comprises no quadrupole magnet about a circulating path of said charged particle beam in said synchrotron.

10. A method for generating a negative ion beam for use with charged particle radiation therapy, comprising the steps of:
providing a magnetic material;
providing a high temperature plasma chamber substantially encompassing said magnetic material, wherein said high temperature plasma chamber comprises: a first ion generation electrode at a first end of said high temperature plasma chamber, a second ion generation electrode at a second end of said high temperature plasma chamber, and a magnetic field carrying outer wall circumferentially surrounding said high temperature plasma chamber;
applying a first high voltage pulse across said first ion generation electrode and said second ion generation electrode breaking hydrogen in said high temperature plasma chamber into component parts;
wherein said magnetic material yields a magnetic field loop running through said first ion generation electrode, through said magnetic field carrying outer wall, through said second ion generation electrode, across a gap, and through said magnetic material;
wherein said magnetic field loop yields a magnetic barrier across said gap between said high temperature plasma chamber and a low temperature plasma region, said magnetic barrier passing a subset of said component parts;
wherein low energy electrons interact with atomic hydrogen to create hydrogen anions in said low temperature plasma region; and
applying a second high voltage pulse across said second ion generation electrode and a third ion generation electrode, wherein said second high voltage pulse extracts negative ions from said negative ion source into a negative ion beam.

11. The method of claim 10, wherein said first high voltage pulse comprises a pulse of at least four kilovolts for a period of at least fifteen microseconds.

12. The method of claim 10, wherein said second high voltage pulse comprises a pulse of at least twenty kilovolts during a period overlapping the last five microseconds of said first high voltage pulse.

13. The method of claim 10, wherein said second high voltage pulse comprises a pulse of at least twenty kilovolts during a period overlapping at least three microseconds of said first high voltage pulse.

14. The method of claim 10, further comprising the steps of:
providing a first focusing electrode circumferentially surrounding the negative ion beam;
providing a second focusing electrode, said second focusing electrode comprising conductive paths at least partially blocking the negative ion beam;
applying an electric field across said first focusing electrode and said second focusing electrode, wherein electric field lines run between said first focusing electrode and said second focusing electrode,
wherein the negative ion beam encounters force vectors running up the electric field lines that focus the negative ion beam.

15. The method of claim 14, wherein said first focusing electrode comprises a negative charge, wherein said second focusing electrode comprises a positive charge.

16. The method of claim 15, wherein said conductive paths comprise any of:
a series of conductive lines running substantially in parallel across the negative ion beam;
a conductive grid crossing the negative ion beam; and
a foil crossing the negative ion beam, said foil having holes with combined areas of at least ninety percent of the cross-sectional area of the negative ion beam.

17. The method of claim 16, wherein said conductive paths block less than ten percent of the cross-sectional area of the negative ion beam.

18. The method of claim 17, further comprising the steps of:
providing a synchrotron;
converting the negative ion beam into a proton beam at a foil; and
injecting the proton beam into said synchrotron;
wherein said synchrotron comprises four turning sections, wherein each of said turning sections turns the charged particle beam about ninety degrees;
wherein said synchrotron comprises no quadrupole magnet about a circulating path of the charged particle beam in said synchrotron.