Abstract:
A patient alignment system for diagnostic and therapeutic procedures where the embodiment is mounted or referenced to the patient positioning interface such as add-on positioning devices, or directly with the diagnostic and/or therapeutic treatment table or couch. Some patient and equipment positions can obstruct fixed wall or ceiling mounted lasers or an optical view of the anatomy being imaged or treated and patient set-up and alignment may become less accurate or not possible. The patient alignment system may use lasers, cameras or other optical means, ultrasound or RF transceiver technologies, or a combination of multiple technologies, and be mounted in positions, such as below the treatment table or couch and offer a solution to patient alignment for such circumstances. Prone breast imaging and treatment is one example where this system may be used to advantage.

Description:
RELATED APPLICATIONS 
       [0001]    U.S. Application No. 20090064413 filed on Sep. 5, 2008 is incorporated reference herein in its entirety. 
       BACKGROUND 
       [0002]    Accurate patient alignment can be important when imaging and treating patients. In one implementation, such as cancer radiation therapy, reproducibility of the anatomical position determined by diagnostic imaging modalities such as CT, MR and ultrasound can be crucial in accurately delivering the therapeutic dose using external beam radiation. 
         [0003]    Optical alignment systems, such as lasers and cameras, can be used for patient set-up. In this example, patient set-up generally involves having at least 3 points of reference, on or in the patient. One technique is to apply tattoos to the patient&#39;s skin during the imaging procedure in chosen locations. During subsequent treatment procedures, the tattoos are used in conjunction with wall and/or ceiling mounted lasers to re-align the patient to the same relative position and alignment as during the imaging procedure. The wall and ceiling mounted lasers may be aligned to one virtual point (isocenter) and can guide medical personnel in properly setting up the patient by projecting beams onto the marks previously applied to the patient. Wall and ceiling mounted lasers do not address the needs of some emerging therapies where in one instance the patient or parts of the body are not in the field of view of the alignment system. Prone breast imaging and radiotherapy is one example where wall and ceiling mount lasers and/or optics are not visible on some parts of the anatomy. With the patient in the prone position, it can become uncertain that the breast is in the same position from day to day. For example, the imaging process used in radiotherapy can start with a CT simulation, where the patient is marked. Lasers and/or cameras are used to determine reference points on the skin of the patient. These points can be marked with a permanent-type marker or even tattooed. During the treatment planning process, the relative position of the patient markings to the target volume to be treated is measured. Using these marks at a later time, the imaged/simulated patient set-up can be reproduced for the delivery of therapeutic radiation. This process assumes that the target volume within the patient to be treated does not move relative to the marks on the surface of the patient. It is therefore useful to have the marks on the patient in close proximity to the target volume to minimize the alignment error. Using the prone position breast treatment as an example, the back of the patient may be marked for alignment as it is the only surface of the patient accessible from the ceiling mounted laser. As the mark on the back of the patient is a significant distance from the breast and the anatomy is not rigid, set-up accuracy is not maximized with this approach. Reproducibility can also play an important role in multi-modality imaging where data sets from one modality such as CT are merged with another such as MR, PET, or ultrasound. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  is an illustration of one set-up of the alignment system using a single alignment system without being attached to any surfaces. 
           [0005]      FIG. 2  is an illustration of another set-up where more than one alignment system can be used. 
           [0006]      FIG. 3  is an illustration of an alignment system that can be used in conjunction with an add-on patient positioning system, such as ClearVue™ prone breast table. 
           [0007]      FIG. 4  is an illustration of an alignment system that can be used directly with an imaging or treatment couch/table, again using breast an example. 
       
    
    
     DETAILED DESCRIPTION 
       [0008]      FIG. 1  shows one implementation of an alignment system comprising a housing  10 , a mounting fixture  20 , an alignment element  30 , a positioning mechanism  40 , a power switch  50 , a power supply  60 , and an adjustment mechanism  70 . The housing  10  can be made from any suitable material such as metal, plastic wood, composite or the like, and can be a container-like structure of any shape or size. The mounting fixture  20  can be of various shape and size and may have a combination of materials and sub-components such as bolts, screws and the like. The alignment element  30  can be a laser, still camera, video camera, projector, ultrasound device, RF transceiver or the like. 
         [0009]    The positioning mechanism  40  can be a rail or any other mechanism allowing motion along one, or more axes and it can be manually or automatically driven and may contain motors. Power switch  50  can be manual, automatic, on/off, timer controlled, or remote controlled. The power supply  60  can be battery or mains powered, and it can be located on the device or separately. The adjustment mechanism  70  can be made from any stable material such as metal, plastic or the like and can include pivots, screws, ball joints or the like. The alignment system may employ multiple fixed alignment elements instead of one moveable unit. 
         [0010]    The housing  10  may function as the container for the alignment element  30  and can hold or contain any or all of the described elements. The mounting fixture  20  may function as the mounting piece to attach the alignment system to add-on patient positioning devices, patient exam tables, treatment couches, diagnostic couches, or any other stable material. The alignment element  30  can act as an emitter, such as a laser or projector, to emit for an example a laser beam  17  or an alignment pattern within field of view  19 . The alignment element  30  can also act as a receiver, such as a camera, or be a combination of both the transmitter and a receiver. 
         [0011]    The positioning mechanism  40  may function to allow the movement of the alignment element  30  in any direction along all 3 axes. The power switch  50  may function to turn the system power on an off. It can be a toggle, push button or the like, and can be activated at the device or remotely. It can be timer controlled to remain on for a certain period of time. The power supply  60  can power the system and include a timer to turn the alignment element  30  on and off. The adjustment mechanism  70  may rotate along all axes to move or rotate the alignment element  30 . The housing  10  may act as a container to contain or hold together the alignment element  30 , positioning mechanism  40 , power switch  50 , power supply  60 , mounting fixture  20 , adjustment mechanism  70  and the like. The mounting fixture  20  can be permanently or temporarily connected to housing  10 , and can vary for different mounting options depending on placement of the alignment system. The alignment element  30  can be mounted onto the adjustment mechanism  70  or it can be mounted on the housing  10  or it can be mounted on the positioning mechanism  40 . The adjustment mechanism  70  can be mounted to the alignment element  30  and can move the alignment element  30  along all axes and directions to point the alignment element  30  in the desired direction. The positioning mechanism  40  may have mountings for the adjustment mechanism  70  or alignment element  30 . The positioning mechanism  40  may allow the alignment element  30  and/or adjustment mechanism  70  to move along one or more axes. The power switch  50  can be connected to the power supply  60  and function to turn the system on and off. The power supply  60  can be connected to provide power to the alignment element  30 , adjustment mechanism  70 , positioning mechanism  40  and other elements requiring power. One activated by the user, the power supply  60  would supply power to the active alignment elements  30  enabling the user to mark or record the patient position information during the imaging procedure, and later, during the patient set-up for the therapy procedure, allow the alignment elements  30  to illuminate, display, or measure the marked or recorded patient position information to facilitate correct patient anatomy positioning. 
         [0012]      FIG. 2  describes one implementation of an alignment system comprising a housing  21 , a mounting fixture  23 , more than one alignment element  25 , a power control  29 , a power supply  37 , and adjustment mechanism  27 . More than one alignment element can be employed for the projection of multiple crossing laser lines, for example, or a plurality of transceiver elements for use with radio frequency surface markers or implants. The housing  21  can be made from any stable material such as metal, plastic, wood, composite or the like, and can be a container-like structure of any shape or size. The mounting fixture  23  can be of various shape and size and may have a combination of materials and sub-components such as bolts, screws and the like. The alignment elements  25  can be laser, still camera, video camera, projector, ultrasound device, RF transceiver or the like. Power switch  29  can be manual, automatic, on/off, timer controlled, or remote controlled. The power supply  37  can be battery or mains powered, and it can be located on the device or remotely. The adjustment mechanism  27  can be made from any stable material and can include pivots, screws, ball joints or the like. The housing  21  can function as the container for the alignment system and can hold or contain any or all of the described elements. The mounting fixture  23  can function as the mounting piece to attach the alignment system to add-on patient positioning devices, patient exam tables, treatment couches, diagnostic couches, or any other stable material. The alignment elements  25  can act as emitters, such as a laser or projector, to emit for an example a laser beam  33  or a projected image within a field of view  35 . The alignment elements  25  can also act as receivers, such as a camera, or be a combination of both the transmitter and a receiver. The alignment system can be configured to record images of the anatomy at one time, then project the same or other image at another time to facilitate alignment of the anatomy from day to day. The power switch  29  may function to turn the system power on an off. It can be a toggle, push button or the like, and can be activated at the device or remotely. It can be timer controlled to remain on for a certain period of time. The power supply  37  can power the system on and off. The adjustment mechanisms  27  may rotate along all axes to move or rotate the alignment elements  25 . The housing  21  may act as a container to contain or hold together the alignment elements  25 , power switch  29 , power supply  37 , mounting fixture  23 , adjustment mechanisms  27  and the like. The mounting fixture  23  can be permanently or temporarily connected to housing  21 , and can vary for different mounting options depending on placement of the alignment system. The alignment elements  25  can be mounted onto the adjustment mechanisms  27  or it can be mounted on the housing  21 . The adjustment mechanisms  27  can be mounted to the alignment elements  25  and can move the alignment element along all axes and directions to point the alignment element in the desired direction. The adjustment mechanisms  27  can be manual, motorized, or automated and programmable locally or remotely. The power switch  29  can be connected to the power supply  37  and function to turn the system on and off. The power supply  37  can be connected to provide power to the alignment elements  25 , adjustment mechanisms  27 , and other elements requiring power. In one implementation of  FIG. 2 , where the alignment elements are line-projecting lasers, one horizontal line can be projected which is wide enough to illuminate the left or right breast, or both. Two vertical line projecting lasers can be used, one that aligns with the left breast, and one for the right breast. In use, during the imaging procedure, the breast is marked at the intersection of the two crossing laser lines. Later, during the therapy procedure, the patient position is adjusted so that the mark is again aligned to the crossed laser lines. In one implantation of  FIG. 2 , multiple cameras are mounted to provide imaging capability in one or more directions for each breast. The outline of the patient anatomy and any surface features or marks can be recorded at the time of the imaging procedure. During patient set-up for the therapy procedure, the previously acquired images can be displayed along with the real-time images in order to show the magnitude and direction of the motion required to move the patient into alignment with the earlier reference images. The required motion can be computed using algorithms commonly used in machine vision for inspecting and positioning parts. In one implementation of  FIG. 2 , the alignment elements consist of co-axial image recording and projection devices. During the imaging procedure, an image of the patient anatomy and any surface features or marks can be recorded with the image recording device. During the later therapy or imaging procedure, the projector can project the same image recorded earlier or any other image from the same point of view to assist in the repositioning of the patient for improved alignment of the target volume to the treatment modality. In one implementation of  FIG. 2 , the alignment elements consist of transceivers that can interface with radio frequency transponders on the patient&#39;s skin or implanted transponders within the patient&#39;s anatomy. These transponders can also be visible in the anatomical views generated during the imaging procedure. 
         [0013]      FIG. 3  shows one implementation of the patient alignment system  39 , where it can be used with add-on patient support system  41  that can be used in conjunction with imaging or treatment table/couch  43 . The patient alignment system  39  can be comprised of the system described in  FIG. 1  and  FIG. 2 . The imaging or treatment table/couch  43  can be an examination table, CT table, ultrasound table, MRI table or couch, particle beam therapy table or couch, or the like. The add-on support system can be a patient positioning device, such as the ClearVue™ prone breast table, or the like. The imaging or treatment table/couch  43  can be used to position and examine the patient, obtain diagnostic images, perform biopsies and/or surgical procedures, deliver radiotherapy treatment, deliver hyperthermia treatment, or the like. The add-on patient support system  41  can be used to position the patient  49  in a unique way, for example placing a breast patient in the prone position. The alignment system  39  can be used to align the patient  49  using a projector or emitter such as the laser beam  47 , or receiver, such as the optical camera  45 . The add-on patient support system  41  may be placed on top of the imaging or treatment table/couch  43 . The patient  49  can be positioned on top of the add-on support system  41 , and the alignment system  39  can be used to align the patient  49  to the desired position. After the patient is positioned on the support system, the imaging study can be conducted. In conjunction with the imaging study, the alignment system  39  can be activated and the patient marked on the surface or profile and surface markings acquired for contemporaneous or later use. The patient alignment system may also determine and record the position of surface or implanted RF tags at any time during the imaging session. The position information is recorded on the patient through marking, electronically through image or marker position acquisition and stored 
         [0014]      FIG. 4  shows one implementation of the patient alignment system  53 , where it can be used as an integrated part of the imaging or treatment table/couch  51 . The patient alignment system  53  can be comprised of the system described in  FIG. 1  and  FIG. 2 . The imaging or treatment table/couch  51  can be an examination table, CT table, ultrasound table, or MRI table or couch, particle beam therapy table or couch, or the like. The imaging or treatment table/couch  51  can be used to examine the patient, obtain diagnostic images, perform biopsies and/or surgical procedures, deliver radiotherapy treatment, deliver hyperthermia treatment, or the like. The alignment system  53  can be used to align the patient  59  using a projector or emitter such as the laser beam  55 , or receiver, such as the optical camera  57 . The patient  59  can be positioned on top of the imaging or treatment couch/table  51 , and the alignment system  53  can be used to align the patient  59  to the desired position.