Abstract:
Systems and methods of controlling characteristics of a proton beam emitted from a nozzle of a proton treatment system including one or more beam modifying members to define a characteristic of an emitted proton beam, and a clamping member mounted to the nozzle, the clamping member having one or more receiving portions to receive the one or more beam modifying members therein. In some embodiments, the beam modifying members comprise plate structures and the receiving portions include a plurality of slots spaced apart from one another on opposing surfaces of the clamping member to receive opposing ends of the plate structures.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/880,404, filed on Sep. 20, 2013, the disclosure of which is incorporated herein in its entirety by reference. 
     
    
     FIELD OF INVENTION 
       [0002]    The present general inventive concept relates to proton therapy for cancer treatment, and more particularly to a system to modify characteristics of a proton beam emitted from a proton treatment system. 
       BACKGROUND 
       [0003]    Proton Therapy (PT) is a cancer treatment technology that uses high energy protons to penetrate a patient&#39;s body and deposit energy into treatment areas such as cancerous tumors. PT leverages the Bragg peak property of charged particles, such as protons, to deposit the majority of the particle&#39;s energy in the last few millimeters of travel, as opposed to conventional radiation therapy where the majority of energy is deposited in the first few millimeters of travel—which often causes significant damage to healthy tissue. 
         [0004]    PT systems commonly implement a rotating gantry wheel to direct a beam of protons into the patient through a proton delivery nozzle from various positions around the patient during the course of treatment. The beam of protons directed into the patient is targeted into the three-dimensional shape of the desired treatment volume to deliver the therapeutic radiation precisely to the targeted location, while sparing the surrounding healthy tissue. A proton beam with a smaller cross sectional area provides greater precision in targeting, but requires more time and rotation of the gantry wheel than using a beam with a larger cross sectional area and clinicians must replace the snout of the PT system when changing between cross sectional areas. 
         [0005]    The characteristics of the beam can include shape, size, cross-section, intensity, energy, etc. Thus, the characteristics of the proton beam include the cross-sectional shape and size of the proton beam, as defined by the aperture in the proton delivery nozzle. Traditional apertures are supported in place by a shielded snout that directs the flow of charged particles through the aperture. To shape or trim the beam of protons, the snout may include collimators to define and limit the spread of the proton beam, degraders to limit the intensity of the beam of protons, and compensators to affect the distance from the proton delivery nozzle that the charged particles deliver the majority of their energy. To change the aperture size or the trimming and focal properties of the proton beam in traditional proton nozzles, the entire snout assembly typically needs to be replaced, in addition to the clamp assembly, which can add time to the treatments using PT due to equipment change-outs. Further, because the snout contains radiation shielding, the snout is heavy and cannot be changed out without mechanical assistance. 
       BRIEF SUMMARY 
       [0006]    Example embodiments of the present general inventive concept can be achieved by providing systems and methods that allow for the rapid modification of the nozzle aperture for various beam modifying effects without requiring a snout change. Example embodiments include a system to control characteristics of a proton beam emitted from a nozzle of a proton treatment system, including one or more beam modifying members to selectively define a characteristic of an emitted proton beam, and a clamping member mounted to the nozzle, the clamping member having one or more receiving portions to respectively receive the one or more beam modifying members therein. 
         [0007]    Example embodiments of the present general inventive concept can also be achieved by providing a system to control characteristics of a proton beam emitted from a nozzle of a proton treatment system, including one or more beam modifying members to define a characteristic of an emitted proton beam, and a clamping member mounted to the nozzle, the clamping member having one or more receiving portions to receive the one or more beam modifying members therein. 
         [0008]    The beam modifying members can be configured as a first set of plates, and the receiving portions can include a plurality of slots spaced apart from one another on opposing surfaces of the clamping member to receive opposing ends of each first plate. 
         [0009]    The clamping members can include one or more detector units to detect the presence of a beam modifying member within the clamping member. 
         [0010]    At least one of the beam modifying members can include a second clamping member having at least one receiving portion smaller than the receiving portions of the first clamping member to respectively receive one or more other beam modifying members therein. 
         [0011]    One or more other beam modifying members can be configured as a second set of plates smaller than the first set plates, and the receiving portions of the second clamping member can include a plurality of slots spaced apart from one another on opposing surfaces of the second clamping member to receive opposing ends of each second plate. 
         [0012]    The second clamping member can include one or more detector units to detect the presence of at least one beam modifying member within the second clamping member. 
         [0013]    The clamping member can be disposed adjacent to a proton delivery nozzle aperture of the proton treatment system and downstream from the nozzle aperture. 
         [0014]    The one or more and other beam modifying members can include one or more of a place-holder plate, aperture plate, collimator plate, compensator plate, degrader plate, or combinations thereof. The place-holder plate may not significantly modify the proton beam. The aperture plate may define a cross sectional area of the proton beam. The collimator plate may align the proton beam. The compensator plate may affect the Bragg peak distance of the proton beam. The degrader plate may reduce an intensity of the proton beam. 
         [0015]    A plurality of beam modifying members can be stacked together side by side within the clamping member. 
         [0016]    The one or more beam modifying members can include annular shielding. 
         [0017]    The system may further include a compensator integrated with at least one beam modifying member. 
         [0018]    The system may further include an output unit in communication with the one or more detector units to output presence information of a beam modifying member within the clamping member and/or second clamping member. 
         [0019]    The one or more beam modifying members can include a handle portion to facilitate gripping of the beam modifying members by an operator of the proton treatment system. 
         [0020]    The proton treatment system can include a snout, and the one or more beam modifying units can be interchanged in the clamping members without removing the snout from the proton treatment system. 
         [0021]    Example embodiments of the present general inventive concept can also be achieved by providing a method of controlling characteristics of a proton beam emitted from a nozzle of a proton treatment system, including mounting a clamping member to a nozzle of a proton treatment system, the clamping member having one or more receiving portions provided therein, and interchangeably sliding one or more beam modifying members into a respective receiving portion, the one or more beam modifying members being selected to define a characteristic of a proton beam emitted from the nozzle, wherein the beam modifying members are configured as a first set of plates having a first size, and the receiving portions include a plurality of slots spaced apart from one another on opposing surfaces of the clamping member to receive opposing ends of each first plate, and wherein at least one of the beam modifying members includes a second clamping member having at least one receiving portion smaller than the receiving portions of the first clamping member to respectively receive one or more other beam modifying members therein. 
         [0022]    The method may further include detecting the presence of at least one beam modifying member within the clamping members, and outputting presence information of the least one beam modifying unit to an output unit of the proton treatment system. 
         [0023]    Additional features and embodiments of the present general inventive concept will be set forth in part in the following description and, in part, will be obvious from the description, or may be learned by practice of the present general inventive concept. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The following example embodiments are representative of example techniques and structures designed to carry out objectives of the present general inventive concept, but the present general inventive concept is not limited to these example embodiments. In the accompanying drawings and illustrations, the sizes and relative sizes, shapes, and qualities of lines, entities, and regions may be exaggerated for clarity. A wide variety of additional embodiments will be more readily understood and appreciated through the following detailed description of the example embodiments, with reference to the accompanying drawings in which: 
           [0025]      FIG. 1  is a frontal view of loading an aperture plate into a clamp; 
           [0026]      FIG. 2  is an isometric view of a beam projector fitted with a clamp with an aperture plate, detailing the plate holders of the clamp; 
           [0027]      FIG. 3A  is an exploded isometric view of one embodiment of an adaptive aperture clamp with a large field projection; 
           [0028]      FIG. 3B  is an isometric view of one embodiment of an adaptive aperture clamp with a large field projection; 
           [0029]      FIG. 4A  is an exploded isometric view of one embodiment of an assembled adaptive aperture clamp with a small field projection; and 
           [0030]      FIG. 4B  is an isometric view of one embodiment of an assembled adaptive aperture clamp with a small field projection. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    Reference will now be made to the following example embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings. The example embodiments are described herein in order to explain the present general inventive concept by referring to the figures. 
         [0032]    Example embodiments of the present general inventive concept enable a proton beam operator to quickly change a proton beam shape and size, for example, by selectively sliding multiple interchangeable beam modifying members, or plates, into a clamp mechanism for purposes of collimation, beam shaping, degrading, etc., without a time consuming snout change. Patients can receive large doses of radiation to the larger volumes of targeted locations and more precise doses of radiation to smaller volumes, particularly treatment from a direction having critical anatomic structures nearby the proton beam, of targeted locations, which can improve the efficacy and speed of treatment. It is noted that the term ‘plate’ may be used herein to refer to various components, but it is understood that the components are not limited to a plate-shape, or any particular shape. A variety of other shapes in addition to plate-shapes could be chosen with sound engineering judgment to configure the various components. The beam modifying members can be selectively installed by an operator of the proton therapy system, or they can be selected and installed by an automated system, such as a robot, based on a particular treatment plan. 
         [0033]      FIG. 1  is a frontal view illustrating loading of an example embodiment beam modifying member such as aperture plate  120  into a clamp mechanism or clamping member  110  of the present general inventive concept. The aperture plate  120  defines an aperture  121  through which a beam of charged particles, such as a proton beam, is transmitted, with a shielded portion  122 , which attenuates and/or reflects a portion of the beam that is not directed through the aperture  121 . The aperture plate  120  can be slidably inserted into respective receiving portions of the clamp  110 . In the illustrated example embodiment, the clamping member  110  is generally C-shaped with slots disposed on opposing surfaces of the clamp to receive one or more beam modifying members therein through one side. The beam modifying member, such as aperture plate  120 , is in some embodiments shaped in the form of a plate to be received in a corresponding slot. In some embodiments, the clamping member  110  includes a locking element  111  to secure the aperture plate  120  to the clamping member  110  relative to the nozzle aperture  201 . The locking member can take the shape of a protruding member  111   a  extending into the receiving slots of the clamping member  110  to secure and locate the beam modifying member via a mating receiving portion  111   b,  e.g., cutout, which receives the protruding member  111   a.  The protruding member can be spring loaded and/or lever driven such that the protruding member extends into the receiving portion to locate and/or drive the beam modifying member  120  into position as the beam modifying member is installed in the clamping member. The locking member can take a variety of configurations, such as a lever actuated sliding lock, spring loaded detent, etc., without departing from the broader spirit and scope of the present general inventive concept. Those skilled in the art will appreciate that although the embodiment of  FIG. 1  illustrates a generally C-shaped clamp mechanism design, various clamp designs and shapes could be used, such as a slide-through design, a square-like shape, or other shape design, without departing from the scope and spirit of the present general inventive concept. 
         [0034]      FIG. 2  is an isometric view of a beam projector fitted with a clamp  110  and aperture plate  120 , detailing example plate holders  112  of the clamp. Referring to  FIG. 2 , the clamping member  110  includes plate holder  112 , such as plate-slots  112   a,    112   b,    112   c  in which an aperture plate  120  or other plate types can be secured. The clamping member  110  illustrated in  FIG. 2  is in some embodiments attached to a proton delivery nozzle  200  secured over a nozzle aperture  201 . The lock  111  secures one or more aperture plates within plate-slots  112   a - c.  Plates secured in the plate-slots  112   a - c  can affect the beam or merely be place-holders for plates to occupy a plate-slot  112  without affecting the beam. Although the example embodiment of  FIG. 2  illustrates three (3) plate-slots, more or less slots could be provided without departing from the broader scope and spirit of the present general inventive concept. 
         [0035]    As described in further detail below, various types of plates can include, but are not limited to, aperture plates to trim the cross sectional area of the beam, beam collimator plates to collimate the particles in the beam, compensator plates to affect the Bragg peak effect&#39;s distance of majority energy delivery for particles in the beam, clamp plates to enable additional plates to affect the beam, and various combinations thereof. In particular, some example embodiments of the present general inventive concept include incorporating a precollimator as part of the apparatus holding a smaller sized aperture plate, providing for full radiation shielding of the patent with respect to the proton delivery nozzle. 
         [0036]      FIGS. 3A and 3B  illustrate an example embodiment of an adaptive aperture clamp  100  adapted for a large field projection. The illustrated embodiment uses two aperture plates  120   a,    120   b  and a combination aperture/compensator plate  140   a  in its plate-slots  112 . The aperture plates  120   a,    120   b  define apertures  121   a,    121   b  smaller in cross sectional area than the aperture  201  of the proton delivery nozzle  200 , which trims the field size of the projected beam of charged particles. The two aperture plates  120   a,    120   b  are seated in the clamp&#39;s plate-slots  112   b,    112   c  proximal to the proton delivery nozzle  200  and a compensator plate  140   a  is placed in the distal plate-slot  112   a.  In this arrangement, the compensator plate  140   a  is downstream from the two aperture plates  120   a,    120   b  and affects the Brag peak distance for charged particles in the beam. 
         [0037]      FIGS. 4A and 4B  illustrate an example embodiment of an adaptive aperture clamp  100  adapted for a small field projection. The illustrated embodiment uses two aperture plates  120   b,    120   a,  a clamp plate  150   a,  two collimator plates  130   b,    130   a,  and a compensator plate  140   b  in its plate stack—arranged from upstream to downstream in this example. The illustrated embodiment builds on the embodiment of  FIGS. 3A and 3B  by adding a clamp plate  150   a  in place of the compensator plate  140   a,  enabling additional plates to be added to the plate stack to further define and affect the beam of charged particles by providing additional plate-slots  152 . The clamp plate  150   a  has an aperture  153   a  substantially equal or larger in cross sectional area than the apertures  121   a,    121   b  ( FIG. 3A ) of the upstream aperture plates  120   a,    120   b  and has a lock  151   a  to secure plates into its clamp plate plate-slots  152   a,    152   b,    152   c.  In  FIG. 4B , the precollimator plates  120   a,    120   b  provide both a mechanism for mounting the patient collimators  130   a,    130   b  and the additional, annular shielding required for full patient protection. 
         [0038]    Referring to  FIGS. 3A and 4A , the clamping member  110  can include one or more detection units  1111 , such as switches or detectors, for detecting the presence of the aperture plates in the larger field size. The detection units can be actuated when the aperture plate(s) are installed in the clamping member  110 . The detection units can be mechanical devices, electronic devices, optical devices, or other types of known or later developed detection units. 
         [0039]    As illustrated in  FIG. 4A , detector units  1111  can be installed in another clamping member  1110  of the precollimator plates  120   a,    120   b  to detect the presence of aperture plates  130   a,    130   b  in the smaller field size. Alternatively, the precollimator plates could carry detector mechanisms that are triggered directly by patient collimators  130   a,    130   b.    
         [0040]    The detector units  1111  can be connected to an output unit  1000  to output presence and position information of the beam modifying members to monitor presence of patient apertures or other beam modifying members. The connection can be a wired or wireless electrical or optical connection, or other known or later developed connection method. The detector units can be used to confirm presence of an aperture or compensator plate within one or more clamping members. An array of detector units could be used to read a machined, binary code on the aperture plates and/or compensator plates. For example, four switches encoding four bits of digital information, or eight switches encoding eight bits, could be implemented, but the present general inventive concept is not limited thereto. 
         [0041]    An option for integrating function is to integrate the aperture with compensator. The compensator material is a thermoplastic, typically acrylic or polyethylene. The aperture blank could be insert molded to the compensator blank. The the resulting composite blank would have the aperture and compensator sections machined in coordinated operations, then there would be one less device to be handled. 
         [0042]    The apertures plates are typically quite heavy and can be difficult to handle. Handling can be improved by the addition of handling features. The figures show an aperture plate with a handle  123  integral to the material of the aperture, machined at the time a blank is made or machined at the time the final aperture is made. The handle portion can facilitate gripping of the aperture plates by an operator of the proton therapy system to enable the operator to quickly remove and/or install the plates into a respective clamping member, to change characteristics of the proton beam according to a particular treatment plan. Another option for adding a handle include adding additional holes during machining the aperture or blank with female-threaded holes to receive screw retaining a re-usable handle. The handle can be attached during use, removed and re-used on another aperture plate, keeping its cost relatively low. A handle which wraps all the way around the aperture can be used as an aperture carrier, i.e., another re-usable device which adds the ability to define locating features which may not be suited to the machined aperture itself. 
         [0043]    While embodiments are described herein, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional modifications will readily appear to those skilled in the art. The general inventive concept in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant&#39;s general inventive concept.