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The present invention relates to a method for delivering actively scanned pencil beams combined with dynamic longitudinal scanning for use in particle beam radiation for therapeutic applications. More specifically, the present invention relates to the delivery of charged particle beams of various species generated from a Rapid Cycling Synchrotron (RCS) or similar device to treat deep-seated cancer and noncancerous lesions.
Modern day radiation therapy (RT) of tumors involved optimizing: target dose escalation healthy tissue dose reduction and dose fractionation. It is known in the art that tumors can be eradicated if a sufficient dose is delivered to the tumor volume; however, complications may result from use of the necessary effective radiation dose, due to damage to healthy tissue which surrounds the tumor, or to other healthy body organs located close to the tumor. The goal of conformal radiation therapy is to confine the delivered radiation dose to only the tumor volume defined by the margins of the tumor, while minimizing the dose of radiation to surrounding healthy tissue or adjacent healthy organs.
In conventional radiation therapy with x-rays, intensity modulating radiation therapy (IMRT) offers an effective treatment for certain types of tumors and deep-seated lesions when a sufficient radiation dose is delivered. Cancer cells are often more sensitive to radiation damage than is surrounding healthy tissue due to inefficient repair. IMRT is delivered by external source of radiation from either a gamma emitter or linear accelerator.
The linear accelerator typically has a radiation beam source which is rotated about the patient and directs the radiation beam toward the tumor to be treated. The beam intensity of the radiation beam is predetermined and optimized for all azimuthal rotation angles. Multileaf collimators, which have multiple leaf, or finger, projections which can be moved individually into and out of the path of the radiation beam, can be programmed to follow the spatial contour of the tumor as seen by the radiation beam as it passes through the tumor, or the “beam's eye view” of the tumor during the rotation of the radiation beam source, which is mounted on a rotatable gantry of the linear accelerator. The multiple leaves of the multileaf collimator form an outline of the tumor shape as presented by the tumor volume in the direction of the path of travel of the radiation beam, and thus block the transmission of radiation to tissue disposed outside the tumor's spatial outline as presented to the radiation beam, dependent upon the beam's particular azimuthal orientation with respect to the tumor volume.
Tumors that are located deep within the body are generally not amenable to internal forms of treatment. The intrinsic nature of conventional radiation therapy with x-rays always includes damage to healthy tissue as it enters and exits the tumor volume and conformity is limited to the superposition of intersecting beams.
Another form of external beam radiotherapy is intensity modulated particle therapy (IMPT), which relies on the ballistic nature of particles to produce an inverse depth dose. Particle therapy typically utilizes an accelerator to generate high-energy protons to deposit dose in its path to a tumor before stopping at a precise depth know as its range. Particles heavier then protons such as carbon ions are additionally used to take advantage of higher linear energy transfer (LET) in causing more effective biological damage. Specifically, the charged particles damage the DNA within the cells reducing the reproduction of the cell. The higher mass particles such as carbon ions produce more DNA damage per unit of physical dose. This effect is characterized as relative biological effectiveness (RBE). Further, the larger mass associated with heavy ions such as carbon are characterized by reduced coulombic multiple scattering and range strangling. This results in high spatial precision given reduced lateral beam widening and sharper distal fall off in the tissue outside the tumor volume. The great advantage of particles either protons or heaver ions is the energy level stops, and thus, they do not produce an exit dose in the patient resulting in reduction of side effects to surrounding tissue. All particles have a variety of energy levels that determines the depth of treatment of the tumor. Delivered to the tissue is maximum deposition of the energy just over the last few millimeters of the particles range called the Bragg Peak. The Bragg Peak is an inverse dose distribution level as shown in
IMRT and IMPT have positive and negative affects to the patient. IMPT takes advantage of both biological and physical effects. The first, is for disease cites that favor the delivery of higher RBE radiation; and second, those treatments where the increased precision of particle therapy is used to reduce unwanted side effects by limiting the dose to normal tissue. In IMPT, the particle distributes high amounts of energy at a specific distance and then has minimal damage to the normal tissue; as opposed to, IMRT has a high level of energy prior to entering into the tissue and reduces the energy level as it enters through the body. Further, depending on the particle mass IMPT can produce narrower pencil beam as a pose to conventional IMRT.
Currently, IMPT is delivered with passive double scattering and active scanning techniques. Double passive scattering is the most common technique that delivers a broad beam that must be adjusted with patient-specific hardware that shapes the beam to conform to the shape of the tumor. Passive double scattering, although still the most widely used technique, is being replaced with a process called active scanning or more commonly called pencil beam scanning (“PBS”) because of the correlation to the optimization algorithm for calculating dose in treatment planning systems (“TPS”). PBS was first introduced by T. Kanai et al. in 1980 and was developed at the Paul Scherer Institute in the mid 1990's. PBS delivers a much more precise beam and has superior 3D dose conformity as compared to passive double scattering.
In addition, there is the spread of Bragg Peaks as illustrated in
Therefore, one of ordinary skill in the art would appreciate for a need to precisely balance against the competing objective of destroying as much of the cancerous tissue as possible and in reducing exposure to healthy tissue. Thus, the objective is to deliver a dose sufficient to eradicate or dramatically reduce the tumor while minimizing the impact on surrounding normal.
High-energy particles can be precisely formed into individual beams described as a pencil beam with spatial and angular dimensions. Charged particles such as protons and carbon ions are characterized with inverse depth dose curves that have specific range associated with particle kinetic energy. This unique dosimetric characteristic provides the 3rd dimension in producing a uniform dose volume with the ability to generate particles at specific energies corresponding to precise penetration depths (z-axis). This 3rd longitudinal dimension, when combined with the 2 transverse planes (x-y), requires scanning each pencil beam along 3 axes (x-y-z). Each pencil beam is composed of individual pristine Bragg peak that needs to be scanned in 2 orthogonal transverse (x-y) planes and 1 longitudinal z-axis. The pencil beam is physically repositioned for each transverse (x-y) position while the longitudinal z-axis corresponds to the depth of the tumor and requires the generation of Bragg peaks of different energies one for each depth. To create a uniform dose with depth, many pristine Bragg peaks are layered (stacked) one energy level per transverse scan cycle. A spread out Bragg peak (SOBP) (
Therefore, one of ordinary skill in the art would appreciate a method of delivering ion radiation to a patient in fewer volumetric steps by reducing the scanning of the x-coordinate and y-coordinate, which causes latencies between scanning and delivering dose.
According to one general aspect there is provided an apparatus for delivering longitudinal column of dose rapidly to depth extrema of a tumor comprising a position and tracking module used for a patient position and locating a region of interest, wherein the position tracking module further comprises a registration verification used in conjunction with a patient motion sensor and a tumor motion sensor to determine the exact location of a target voxel, a scanning routine module used for targeting the target voxel within the region of interest by accessing a treatment plan characterization while providing a maximum amount of dose to the target voxel, wherein the scanning routine module determines a maximum amount of dose for the target voxel in all a horizontal index in a single vertical index; and a beam delivery module used for controlling a beaming device that delivers ion particles to the target voxel within the region of interest, wherein the beam delivery module controls a power supply for a horizontal magnet and a vertical magnet by retrieving information from the scanning routine module, wherein the beam delivery module controls a power supply for an accelerator energy selection that is connected to the beaming device, wherein the beam delivery module reads a horizontal strip detector and a vertical strip detector. Furthermore, the apparatus for delivering longitudinal column of dose rapidly to depth extrema of a tumor, wherein the position and tracking module further comprises the tumor motion sensor and the patient motion sensor are connected to a timing module, wherein the tumor motion sensor tracks the region of interest. Furthermore, the apparatus for delivering longitudinal column of dose rapidly to depth extrema of a tumor, wherein the position and tracking module further comprises the timing module is connected to a decision controller that selects a static delivery or a dynamic delivery, wherein the static delivery contains a static time stamp and uses a treatment planning system data used by the scanning routine module, and wherein the dynamic delivery contains an adaptive treatment planning data used by the scanning routine module. Furthermore, the apparatus for delivering longitudinal column of dose rapidly to depth extrema of a tumor, wherein the position and tracking module further comprises the timing module is connected to a beam delivery gate that is used by the beam delivery module. Furthermore, the apparatus for delivering longitudinal column of dose rapidly to depth extrema of a tumor, wherein the scanning routine module further comprises a database treatment planning system that is populate by the beam delivery module and the position and tracking module. Furthermore, the apparatus for delivering longitudinal column of dose rapidly to depth extrema of a tumor, wherein the scanning routine module retrieves from the database treatment planning system a dose prescription, a position location, a position time for a specific voxel, and a flag for dose delivery of the region of interest. Furthermore, the apparatus for delivering longitudinal column of dose rapidly to depth extrema of a tumor, wherein the scanning routine module initiates a delivery beam to the beam delivery module to began delivery of the dose prescription and trigger a stop beam. Furthermore, the apparatus for delivering longitudinal column of dose rapidly to depth extrema of a tumor, wherein the scanning routine module determines the maximum dose prescription by incrementing the position location of a horizontal index until the horizontal index is reached on the single vertical index. Furthermore, the apparatus for delivering longitudinal column of dose rapidly to depth extrema of a tumor, wherein the scanning routine module determines the maximum dose prescription by incrementing the single vertical index for the position location until the vertical index is reached. Furthermore, the apparatus for delivering longitudinal column of dose rapidly to depth extrema of a tumor, wherein the beam delivery module further comprises a beam control interface that is connected the horizontal power supply and the vertical power supply. Furthermore, the apparatus for delivering longitudinal column of dose rapidly to depth extrema of a tumor, wherein the beam delivery module further comprises a beam control interface that is connected an accelerator energy selection power source and accelerator beam intensity control power source. Furthermore, the apparatus for delivering longitudinal column of dose rapidly to depth extrema of a tumor, wherein the horizontal power supply is connected to the horizontal magnet and a magnetic field sensor H. Furthermore, the apparatus for delivering longitudinal column of dose rapidly to depth extrema of a tumor, wherein the vertical power supply is connected to the vertical magnet and a magnetic field sensor V. Furthermore, the apparatus for delivering longitudinal column of dose rapidly to depth extrema of a tumor, wherein the an accelerator energy selection power source is connected to the beam device and a beam fluence sensor. Furthermore, the apparatus for delivering longitudinal column of dose rapidly to depth extrema of a tumor, wherein the accelerator beam intensity control power source is connected to a intensity modulation device, a beam fluence sensor septum and a beam fluence sensor nozzle.
In another general aspect there is provided an method for delivering longitudinal column of dose rapidly to depth extrema of a tumor by locating a region of interest of a patient by a position tracking a registration verification used in conjunction with a patient motion sensor and a tumor motion sensor to determine the exact location of a target voxel, targeting the target voxel with the region of interest by accessing a treatment plan characterization while providing a maximum amount of dose to the target voxel, wherein a scanning routine module determines a maximum amount of dose for the target voxel in all a horizontal index in a single vertical index, and controlling a power supply for a horizontal magnet and a vertical magnet by retrieving information from the scanning routine module, further comprising controlling a power supply for an accelerator energy selection that is connected to a beaming device, wherein a beam delivery module reads a horizontal strip detector and a vertical strip detector. Further, the method for delivering longitudinal column of dose rapidly to depth extrema of a tumor also includes by tracking the region of interest by use of a tumor motion sensor. Furthermore, the method for delivering longitudinal column of dose rapidly to depth extrema of a tumor also includes by selecting a static delivery or a dynamic delivery to the patient by operating a GUI. Furthermore, the method for delivering longitudinal column of dose rapidly to depth extrema of a tumor also includes by populating a database treatment planning system by a beam delivery module and a position and tracking module, delivering a dose prescription to the beam delivery module, measuring a delivery dose from the beam delivery module, incrementing a horizontal index as many times as needed within the region of interest and within the single vertical index, and incrementing the single vertical index as many times as needed with the region of interest.
The invention generally relates to a device that is used to treat patients using rapid cycling regarding particle therapy.
The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses, and/or systems described herein. Accordingly, various changes, modifications, and equivalents of the systems, apparatuses and/or methods described herein will be suggested to those of ordinary skill in the art. Also, descriptions of well-known functions and constructions may be omitted for increased clarity and conciseness.
In the Summary of the Invention above and in the Detailed Description of the Invention, and the claims below, and in the accompanying drawings, reference is made to particular features (including method steps) of the invention. It is to be understood that the disclosure of the invention in this specification includes all possible combinations of such particular features. For example, where a particular feature is disclosed in the context of a particular aspect or embodiment of the invention, or a particular claim, that feature can also be used, to the extent possible, in combination with and/or in the context of other particular aspects and embodiments of the invention, and in the invention generally.
Rapid Range Stacking (RRS) is a pencil beam scanning (PBS) method that delivers an entire spread out Bragg peak (SOBP) in order to fill the longitudinal extent of a tumor volume with radiation quickly prior to repositioning the pencil beam in the transverse plane. This enables the 3D tumor volume to be filled with radiation in a single transverse scanning cycle. A SOBP is the superposition of multiple Bragg peaks with each composed of particles at the specified energy required to penetrate the tumor to the longitudinal depth referred to as range. This invention is the method of rapidly stacking multiple pencil beams with particles with range varying from distal to proximal extent of the tumor.
Next, time module 27 sends information to the beam delivery gate 35. The beam delivery gate 35 is used to communicate dose information at a specific time. The beam delivery gate 35 is used to synchronize the delivery of beam with the moment in time and communicates to the beam delivery when to turn the beam on or off.
SOBP(Z0:Zn)=SUM(C0*Z0:Cn*Zn)
The intensity is modulated from C0 to Cn where the maximum intensity is associated with the beam with the highest energy within the SOBP. Horizontal strip detector 91 provides feedback to beam control interface 63 to verify correct horizontal scan position. Vertical strip detector 93 additionally provides feedback to beam control interface 63 to verify correct vertical scan position.
All the features disclosed in this specification (including any accompanying claims, abstract, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.