Abstract:
A patient support device for use in a medical facility. The patient support device includes a base and a table assembly coupled to the base. The table assembly includes a lower support and an upper support coupled thereto and movable with respect to the lower support. At least one of the upper support and the lower support includes a bearing layer thereon capable of improving the performance of the patient support device when the upper support moves with respect to the lower support.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 60/969,904, filed on Sep. 4, 2007, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to a radiation therapy imaging and treatment system. More specifically, the invention relates to a patient support device for use with such a system. 
       BACKGROUND OF THE INVENTION 
       [0003]    Medical equipment for radiation therapy treats tumorous tissue with high energy radiation. The dose and the placement of the dose must be accurately controlled to ensure both that the tumor receives sufficient radiation to be destroyed, and that damage to the surrounding and adjacent non-tumorous tissue is minimized. Intensity modulated radiation therapy (IMRT) treats a patient with multiple rays of radiation each of which may be independently controlled in intensity and/or energy. The rays are directed from different angles about the patient and combine to provide a desired dose pattern. In external source radiation therapy, a radiation source external to the patient treats internal tumors. The external source is normally collimated to direct a beam only to the tumorous site. Typically, the radiation source includes either high-energy X-rays, electrons from certain linear accelerators, or gamma rays from highly focused radioisotopes, though other types of radiation sources are possible. 
         [0004]    One way to control the position of the radiation delivery to the patient is through the use of a patient support device, such as a couch, that is adjustable in one or more directions. The use of a patient support device is well known in the medical field, with similar patient support devices being used in CT scanning devices and Magnetic Resonances Imagers (MRIs). The patient support device allows the patient to be moved into and out of the field of the radiation to be delivered and in some cases, allow for adjustments of patient position during a radiation treatment. 
       SUMMARY OF THE INVENTION 
       [0005]    When a patient support device such as a couch is to control the position of the radiation delivery to the patient, there are many variables that need to be accounted for. For example, construction materials and configuration of suitable electronics necessary to operate the couch must be carefully selected to ensure smooth operation of the couch, and precise measurement of couch position (when the couch has multiple movable parts). When these features are thoughtfully considered in the environment of radiation delivery, the patient support device can be a key tool in improving patient outcomes. 
         [0006]    The present invention provides a radiation therapy treatment system that includes an improved patient support device. In one embodiment, the patient support device includes a table assembly coupled to a base. The table assembly includes an upper support and a lower support, the upper support being movable with respect to the lower support. In one embodiment, at least a portion of both the upper and lower supports include a bearing layer, designed to improve the performance of the patient support device during movement of the upper support with respect to the lower support. 
         [0007]    In one embodiment, the present invention provides a radiation delivery system comprising a gantry configured to receive a patient, a radiation source coupled to the gantry and operable to deliver radiation to a patient, and a patient support device movable with respect to the gantry. The patient support device comprises a base, and a table assembly coupled to the base, the table assembly including a lower support and an upper support coupled to the lower support, wherein the upper support is movable with respect to the lower support, and at least one of the upper support and the lower support includes a bearing layer thereon capable of improving the performance of the patient support device when the upper support moves with respect to the lower support. 
         [0008]    Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0009]      FIG. 1  is a perspective view of a radiation therapy treatment system. 
           [0010]      FIG. 2  is a perspective view of a multi-leaf collimator that can be used in the radiation therapy treatment system illustrated in  FIG. 1 . 
           [0011]      FIG. 3  is a perspective view of a patient support device for use with the system of  FIG. 1 . 
           [0012]      FIG. 4  is an exploded view of a table assembly of the patient support device of  FIG. 3 . 
           [0013]      FIG. 5  is a perspective view of an upper support of the table assembly of  FIG. 4 . 
           [0014]      FIG. 6  is a perspective view of a lower support of the table assembly of  FIG. 4 . 
           [0015]      FIG. 7  is an assortment of views of a control keypad for use with the patient support device of  FIG. 1 . 
           [0016]      FIG. 8  is an exploded view of the keypad of  FIG. 7 . 
           [0017]      FIG. 9  is a front view of the keypad of  FIG. 7 , illustrating the control buttons in greater detail. 
           [0018]      FIG. 10  is a perspective view of the keypad of  FIG. 7 , illustrating operation of the buttons by the operator of the patient support device. 
           [0019]      FIG. 11  is a perspective view of the patient support device of  FIG. 3 , shown in the lowered position. 
           [0020]      FIG. 12  illustrates a riser of the patient support device of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. 
         [0022]    Although directional references, such as upper, lower, downward, upward, rearward, bottom, front, rear, etc., may be made herein in describing the drawings, these references are made relative to the drawings (as normally viewed) for convenience. These directions are not intended to be taken literally or limit the present invention in any form. In addition, terms such as “first,” “second,” and “third” are used herein for purposes of description and are not intended to indicate or imply relative importance or significance. 
         [0023]    In addition, it should be understood that embodiments of the invention include hardware, software, and electronic components or modules that, for purposes of discussion, may be illustrated and described as if the majority of the components were implemented solely in hardware. However, one of ordinary skill in the art, and based on a reading of this detailed description, would recognize that, in at least one embodiment, the electronic based aspects of the invention may be implemented in software. As such, it should be noted that a plurality of hardware and software based devices, as well as a plurality of different structural components may be utilized to implement the invention. Furthermore, and as described in subsequent paragraphs, the specific mechanical configurations illustrated in the drawings are intended to exemplify embodiments of the invention and that other alternative mechanical configurations are possible. 
         [0024]      FIG. 1  illustrates a radiation therapy treatment system  10  that can provide radiation therapy to a patient  14 . The radiation therapy treatment can include photon-based radiation therapy, brachytherapy, electron beam therapy, proton, neutron, or particle therapy, or other types of treatment therapy. The radiation therapy treatment system  10  includes a gantry  18 . The gantry  18  can support a radiation module  22 , which can include a radiation source  24  and a linear accelerator  26  (a.k.a. “a linac”) operable to generate a beam  30  of radiation. Though the gantry  18  shown in the drawings is a ring gantry, i.e., it extends through a full 360° arc to create a complete ring or circle, other types of mounting arrangements may also be employed. For example, a C-type, partial ring gantry, or robotic arm could be used. Any other framework capable of positioning the radiation module  22  at various rotational and/or axial positions relative to the patient  14  may also be employed. In addition, the radiation source  24  may travel in a path that does not follow the shape of the gantry  18 . For example, the radiation source  24  may travel in a non-circular path even though the illustrated gantry  18  is generally circular-shaped. The gantry  18  of the illustrated embodiment defines a gantry aperture  32  into which the patient  14  moves during treatment. 
         [0025]    The radiation module  22  can also include a modulation device  34  operable to modify or modulate the radiation beam  30 . The modulation device  34  provides the modulation of the radiation beam  30  and directs the radiation beam  30  toward the patient  14 . Specifically, the radiation beam  30  is directed toward a portion  38  of the patient. Broadly speaking, the portion  38  may include the entire body, but is generally smaller than the entire body and can be defined by a two-dimensional area and/or a three-dimensional volume. A portion or area desired to receive the radiation, which may be referred to as a target or target region, is an example of a region of interest. Another type of region of interest is a region at risk. If a portion includes a region at risk, the radiation beam is preferably diverted from the region at risk. Such modulation is sometimes referred to as intensity modulated radiation therapy (“IMRT”). 
         [0026]    The modulation device  34  can include a collimation device  42  as illustrated in  FIG. 2 . The collimation device  42  includes a set of jaws  46  that define and adjust the size of an aperture  50  through which the radiation beam  30  may pass. The jaws  46  include an upperjaw  54  and a lower jaw  58 . The upper jaw  54  and the lower jaw  58  are moveable to adjust the size of the aperture  50 . The position of the jaws  46  regulates the shape of the beam  30  that is delivered to the patient  14 . 
         [0027]    In one embodiment, and illustrated in  FIG. 2 , the modulation device  34  can comprise a multi-leaf collimator  62  (a.k.a. “MLC”), which includes a plurality of interlaced leaves  66  operable to move from position to position, to provide intensity modulation. It is also noted that the leaves  66  can be moved to a position anywhere between a minimally and maximally-open position. The plurality of interlaced leaves  66  modulate the strength, size, and shape of the radiation beam  30  before the radiation beam  30  reaches the portion  38  on the patient  14 . Each of the leaves  66  is independently controlled by an actuator  70 , such as a motor or an air valve so that the leaf  66  can open and close quickly to permit or block the passage of radiation. The actuators  70  can be controlled by a computer  74  and/or controller. 
         [0028]    The radiation therapy treatment system  10  can also include a detector  78 , e.g., a kilovoltage or a megavoltage detector, operable to receive the radiation beam  30 , as illustrated in  FIG. 1 . The linear accelerator  26  and the detector  78  can also operate as a computed tomography (CT) system to generate CT images of the patient  14 . The linear accelerator  26  emits the radiation beam  30  toward the portion  38  in the patient  14 . The portion  38  absorbs some of the radiation. The detector  78  detects or measures the amount of radiation absorbed by the portion  38 . The detector  78  collects the absorption data from different angles as the linear accelerator  26  rotates around and emits radiation toward the patient  14 . The collected absorption data is transmitted to the computer  74  to process the absorption data and to generate images of the patient&#39;s body tissues and organs. The images can also illustrate bone, soft tissues, and blood vessels. 
         [0029]    The system  10  can also include a patient support device, shown as a couch  82 , operable to support at least a portion of the patient  14  during treatment. While the illustrated couch  82  is designed to support the entire body of the patient  14 , in other embodiments of the invention the patient support need not support the entire body, but rather can be designed to support only a portion of the patient  14  during treatment. The couch  82  moves into and out of the field of radiation along an axis  84 . 
         [0030]    With reference to  FIGS. 3-6 , the couch  82  includes a table assembly  92  coupled to a base  93  via a platform  95 . The table assembly  92  includes an upper support  94  movably coupled to a lower support  98 . With particular reference to  FIG. 5 , the upper support  94  is a substantially flat, rectangular support member on which the patient is supported during treatment. The upper support  94  is movable with respect to the lower support  98  to move the patient into and out of the radiation beam  30  during treatment. In the illustrated embodiment, the upper and lower supports  94 ,  98  are composed of a carbon fiber composite, though other suitable compositions of the supports are possible. 
         [0031]    The upper support  94  has an upper surface  102  and a lower surface  106  that contacts an upper surface  110  of the lower support  98 . As shown in the illustrated embodiment, the lower surface  106  includes a bearing layer  114  that is intended to reduce friction between the lower surface  106  and the upper surface  110  of the lower support  98  when the upper support  94  is moved with respect to the lower support  98 . In the illustrated embodiment, the bearing layer  114  is a polyimide laminate that is coupled to the lower surface  106  using a pressure sensitive adhesive. In the illustrated embodiment, the laminate is Kapton™, available from DuPont. When the upper support  94  moves with respect to the lower support  98 , any friction that builds up between the supports can interrupt the operation of the electronics that control the operation of the couch  82  and thus minimizing the friction is one of the goals of the invention. Further, when the supports are composed of a carbon fiber composite, the friction can cause the creation and build-up of carbon dust, which can cause problems with couch operation. Additionally, if the surfaces of the upper and lower supports  94 ,  98  were to contact each other directly, the contact would result in additional wear and possible warping of the supports themselves, which may not only reduce the precision with which the couch can operate to position a patient, but can also cause couch failure. 
         [0032]    In the illustrated embodiment, the entire lower surface  106  is covered by the bearing layer  114 . However, it is understood that in other embodiments, only portions of the lower surface  106  may be covered by the bearing layer and would still fall within the scope of the present invention. Additionally, while a Kapton™ laminate is used as the bearing layer  114  of the present invention, other types of suitable bearing materials or laminates could be used and still fall within the scope of the invention. For example, Teflon® is one such alternative. Any material that has the benefit of providing smooth motion between two moving parts, reducing friction between those parts, and is capable of withstanding radiation in the amounts generated by the treatment system  10  would be suitable for the bearing layer  114 . Furthermore, while a pressure sensitive adhesive is used to bind the bearing layer  114  to the lower surface  106 , other suitable methods of coupling the bearing layer  114  to the surface  106  are possible. 
         [0033]    With reference to  FIG. 4 , the lower support  98  includes two channels  118  that are designed to receive and house wiring necessary for the operation of the couch  82 . In some embodiments, a retaining member  122  is placed over the wiring within the channels  118  to hold the wiring in place and force the wiring to lie straight within the channels  118  to reduce the possibility of the wiring being pinched between the upper support  94  and the lower support  98 . Furthermore, it is desirable to hold the wires in a straight and constant position for image reproducibility. Both the retaining member  122  and the outer sheathing of the wiring itself are composed of radiation resistant material to provide for the protection and proper functioning of the wiring in the high radiation environment of the couch  82 . The spacing and design of the channels  118  are selected to separate the power lines from the data lines to prevent interference problems that occur when the two lines are not sufficiently spaced. The upper surface  110  of the lower support  98  is divided into three segments by the channels  118 , a middle segment  126  and two outer segments  130 . In the illustrated embodiment, there is a bearing layer  134  on the outer segments  130  and the middle segment  126  of the upper surface  110 . Preferably, the bearing layer  134  is of the same material as the bearing layer  114 . In other embodiments of the invention, the middle segment  126  may be void of a bearing layer. 
         [0034]    The couch  82  is movable in the X, Y, and Z directions, as illustrated in  FIG. 1 . Positioning of the couch  82 , and thus the position of the patient, with respect to the gantry  18  and the radiation beam  30  must be precise to ensure that the radiation is delivered to the proper areas of the patient. The movement of the couch  82  is controlled by the couch operator using a control keypad  140 . With reference to  FIGS. 7-10 , the keypad  140  includes elastomeric buttons  144  that operate corresponding portions of a circuit board  148 . In order to move the couch  82  in any manner or direction, the user must not only operate the appropriate button  144 , but also must depress an enable pad (not shown) on the underside of the keypad  140  to reduce the possibility of accidental movement of the couch  82  by an operator who bumps or brushes against the buttons  144 . The ergonomic design of the keypad  140  allows for one-handed operation, as illustrated in  FIG. 10 . Further enhancing the ergonomic benefits of the keypad  140 , there are two symmetrical sets of exterior buttons  152  for moving the couch  82  in the X direction to comfortably allow both right and left handed operation of the keypad  140 . 
         [0035]    Ease of operation of the couch  82  is the main objective of the keypad  140 , which is designed to be intuitive and ergonomic. The smooth, snagproof design includes no exposed metals or electrically conductive materials of any kind, reducing the possibility of shorts in the control mechanism, reducing vulnerability to ESD, and reducing risk of electric shock. The control panel  140  is flush mounted into the side of the couch  82 , and has a contiguous, sealed top surface with no joints or seams to be resistant to infiltration of liquids and other contaminants. The specific elastomers chosen for the buttons are highly resistant to cleaners and solvents, and are also resistant to radiation. The keypad  140  also includes an integrated system status beacon (which indicates the status of the system  10  outside the operation of the couch  82 ), a button  154  for operating the Y-axis clutch, along with a clutch status indicator, and backlit buttons for easy identification. The layout of the buttons  144  is designed to intuitively suggest the movement accomplished by each button. The buttons  144  also provide tactile feedback to the user. Furthermore, the same keypad assembly can fit on either side of the couch  82 , and in some cases the couch  82  is provided with a keypad  140  on both sides. 
         [0036]    Motion in the Y and Z directions is accomplished via operation of the central buttons  156 . The central buttons  156  are dual speed buttons where pushing the button with lesser pressure results in a single contact for slow operation of the couch  82 , and pushing the button with additional pressure results in a second electrical contact resulting in faster movement of the couch  82 . The dual speed aspect of the buttons  156  allows for greater control of the couch  82 , and provides for more efficient couch movement. In turn, greater efficiency in couch movement results in increased patient throughput and reduced fraction delivery time. 
         [0037]    The couch  82  also includes support arms  164  that couple the table assembly  92  to a riser  168  of the base  93 . As shown in the illustrated embodiment, the couch  82  includes two pairs of support arms  164 , with each arm  164  within a pair of arms being parallel to the other. As the table assembly  92  is raised and lowered, a longitudinal axis of each arm  164  within a pair remains parallel to the other arm, and a plane P 1  formed by the longitudinal axes of one pair of arms does not intersect a plane P 2  formed by the longitudinal axis of the other pair of arms. 
         [0038]    The riser  168 , as illustrated in  FIG. 12 , includes several integral leveling feet  172  that allow the riser  168  position with respect to the X, Y, and Z axis position of the gantry  18  (and the floor of the treatment room) to be easily adjusted to assure that the couch  82  is level with respect to the gantry  18 . To adjust the leveling position of the couch  82 , the feet  172 , shown in the illustrated embodiment as screws, are turned individually to level the position of the couch  82  in all three planes (X, Y, and Z). In the illustrated embodiment, the riser includes six feet  172 , though it is understood that other numbers of feet may be used and still fall within the scope of the invention. 
         [0039]    Additional features of this invention can be found in the following claims.