Abstract:
A patient support for a nuclear medicine imaging system has a base a joint and a chair. The chair can pivot or rotate about the joint. This allows the patient chair to assume a patient loading and a patient imaging position with respect to the detectors of the imaging system. Furthermore, the chair is adjustable to improve the ability of a patient region to be covered by the filed of view of the detectors.

Description:
BACKGROUND  
         [0001]    The invention relates to diagnostic imaging equipment, and more particularly relates to those parts of diagnostic imaging equipment that physically support the patient while the patient is undergoing an imaging study. In its most immediate sense, the invention relates to a patient handling system for use with nuclear medicine imaging equipment.  
           [0002]    Nuclear medicine imaging assesses the radionuclide distribution within a patient after the in vivo administration of radiopharmaceuticals. The imaging systems that asses the radionuclide distribution comprise radiation detectors and associated electronics. The imaging systems detect x-ray or gamma ray photons derived from the administered radionuclides.  
           [0003]    Many current nuclear medicine imaging systems often use a table or pallet to support the patient during scanning. This table presents a single fixed planar surface for the patient to lie upon. In general, during an imaging procedure, the medical practitioner performing the scan will start with the table in a loading position. The medical practitioner will place the patient upon the table. The medical practitioner will then move the table into an imaging position, often by moving the table into the field of view of a gamma camera in a detector attached to a gantry.  
           [0004]    Many patients who require nuclear medicine imaging are infirm or otherwise physically debilitated. This can make placing, or loading, the patient onto a patient table difficult and painful for the patient, as well as time consuming for the medical practitioner performing the scan. As patient throughput is a determining factor in the economic viability of any medical scanning procedure, any technique of decreasing the time and difficulty of patient loading is advantageous.  
           [0005]    Some newer nuclear medicine imaging systems utilize smaller gamma cameras specifically for cardiac nuclear medicine imaging. In some such systems, it may be preferable to have the patient sitting while the imaging occurs. Using a chair for patient support in a nuclear medicine imaging system reduces the total area, or footprint, required by the system. Furthermore, it is often much easier to load a patient onto a chair than a table. However, a sitting patient will sag and move in an upright sitting position, leading to a degraded image.  
           [0006]    Thus, there remains a need in the field of nuclear medicine for a patient support that increases ease of patient loading while maintaining a low level of patient movement. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    The above description, as well as further objects, features and advantages of the present invention will be more fully understood with reference to the following detailed description of the preferred embodiments, when taken in conjunction with the accompanying drawings, wherein:  
         [0008]    [0008]FIG. 1 is a side schematic view of a nuclear medicine imaging system with a table for patient support.  
         [0009]    [0009]FIG. 2 is a side schematic view of a nuclear medicine imaging system with a chair for patient support.  
         [0010]    [0010]FIG. 3 is a side schematic view of an embodiment of the present invention.  
         [0011]    [0011]FIG. 4 is a side schematic view of the embodiment shown in FIG. 3 in a second position.  
         [0012]    [0012]FIG. 5 is a side schematic view of another embodiment of the present invention.  
         [0013]    [0013]FIG. 6 is a side schematic view of another embodiment of the present invention.  
         [0014]    [0014]FIG. 7 is a side schematic view of another embodiment of the present invention.  
         [0015]    [0015]FIG. 8 is a side view of another embodiment of the present invention in a second position.  
         [0016]    [0016]FIG. 9 is a side view of the embodiment of FIG. 8 in a second position.  
         [0017]    [0017]FIG. 10 is a perspective view of another embodiment of the present invention.  
         [0018]    [0018]FIG. 11 is a side view of the embodiment shown in FIG. 9.  
         [0019]    [0019]FIG. 12 is a side view of the embodiment shown in FIG. 9 in a loading position.  
         [0020]    [0020]FIG. 13 is a side view of the embodiment shown in FIG. 9 in an imaging position. 
     
    
     DETAILED DESCRIPTION  
       [0021]    [0021]FIG. 1 shows a nuclear medicine imaging system  2  using a pallet-type patient support as described above. The nuclear medicine imaging system  2  includes a fixed gantry  4  and a detector  6  attached to the gantry  4 . A patient table  8  is shown parallel to the floor. In operation, the patient table  8  will be positioned to be clear of the gantry  4  to allow a patient to be loaded onto table  8 . This position is a patient loading position. System  2  is shown in FIG. 1 in a patient loading position. After a patient is loaded on the table  8 , table  8  and the patient is moved into the field of view of the gamma camera within the detector  6 . This is an imaging position of system  2  (not shown). Note that there are many possible imaging positions.  
         [0022]    The detector  4  may move in reference to the gantry  6  via an arm or other device. This detector mobility allows other portions of the patient to be within the field of view of the gamma camera in detector  4 .  
         [0023]    [0023]FIG. 2 shows another nuclear medicine imaging system with a chair-type patient support as described above. The system  10  includes a gantry  12 , a detector  14 , and a patient chair  16 . The detector is attached to the gantry  12 . The chair  16  is fixed in relation to the gantry  12  in this embodiment. The detector  14  may move in relation to the gantry  12 . In operation, the detector  14  is moved so that a patient may be loaded in the chair  16 . The system  10  is shown with detector  14  in such a loading position. The detector  14  may then be moved such that the gamma camera&#39;s field of view covers a portion of the patient. This is an imaging position for system  2 .  
         [0024]    [0024]FIG. 3 shows one embodiment of the present invention. A nuclear medicine imaging system  18  includes a detector  20 , a gantry  22 , and a patient support  24 . The detector  20  is attached to the gantry  22 . While FIG. 3 shows the detector  20  and the gantry  22  movable in relation to the patient support  24 , they may also be fixed to the patient support  24 . The patient support  24  comprises a base  26 , a pivot  28 , and a patient chair  30 .  
         [0025]    In operation, a medical technician may rotate the chair from a vertical (or upright) position to a more horizontal (or reclining) position. It is easier to load patients when the patient support  24  is in a more vertical position, and therefore this position may be called a loading position. FIG. 3 shows nuclear medicine imaging system  18  in its loading position. After loading, the chair may be rotated about pivot  28  to a more horizontal position that is more suitable for imaging.  
         [0026]    [0026]FIG. 4 shows the above embodiment of the present invention shown in FIG. 3 in such an imaging position. This position places the portion of the patient to be imaged within the field of view of the gamma camera within detector  20 . A breaking mechanism may be used with pivot  28  to fix the patient chair  30  in the appropriate loading and imaging positioning. Note that the exact positions that need to be created by the angle of pivot  28 , for loading and imaging, will depend on the position of the gantry  22 , and the patient&#39;s dimensions.  
         [0027]    [0027]FIG. 5 shows another embodiment of the present invention. Note that like numbers indicate like elements. This embodiment shows a motor driven joint  32 . In operation, this allows for faster and easier patient loading and imaging than a manually driven joint.  
         [0028]    [0028]FIG. 6 shows another embodiment of the present invention. The patient chair  30  is shown having a chair back  34 , a chair seat  36  and a leg support  38 . While the patient chair may have any form capable of supporting a patient in the loading and imaging positions, certain conformations of the patient chair may be more advantageous. Specifically, it is often advantageous that a patient have his knees bent in order be more comfortable while remaining still during the length of a scan. FIG. 6 shows a conformation giving this advantage with a back angle between chair back  34  and chair seat  36 , and a leg angle between chair seat  36  and a leg support  38 . The patient support  18  is shown in an imaging position to illustrate the relative positions of the patient&#39;s head and feet.  
         [0029]    [0029]FIG. 7 shows another embodiment of the present invention. First hinge  40  connects chair back  34  and chair seat  36 , and a second hinge  42  connects chair seat  36  and a leg support  38 . Thus the back angle between chair back  34  and chair seat  36  may be adjusted, and the leg angle between chair seat  36  and leg support  38  may be adjusted. An optimal conformation for individual patient comfort and imaging efficacy may therefore be set.  
         [0030]    [0030]FIG. 8 shows another embodiment of the present invention. The nuclear medicine imaging system  44  has a detector  46  that is mounted on gantry  48 , the gantry  48  itself being fixed to the patient support  50 . Thus, the detector  46  moves with the gantry  48 . Imaging in both the upright and reclining positions of patient support  50  is relatively easy to perform in this embodiment. The upright imaging position is particularly useful if the detector uses lighter weight and size technology, such as solid-state radiation detectors. Solid-state detectors, using materials such as Cadmium Zinc Telluride (CZT), directly convert gamma-ray radiation into measurable electric current. Alternatively, a smaller than conventional detector may use a standard scintillation crystal such as Nal with a solid-state photodiode.  
         [0031]    However, generally note that for cardiac imaging in nuclear medicine a detector in an imaging position will usually be at right angles to the patient to optimize image quality.  
         [0032]    A detector  46  allows for many more options in terms of potential fields of view for the gamma camera within detector  46 . However, such a detector  46  may be in the way of patient chair  52  when it is moved from loading to imaging position. Therefore, the detector  46  may have to be moved to a loading position to allow patient access to the patient chair  52  and to allow the patient chair  52  to be moved into imaging position. Then the detector  46  may be moved into an imaging position, as shown in FIG. 9.  
         [0033]    Note that FIGS. 8 and 9 show a detector  46  and gantry  48  with specific degrees or dimensions of freedom. However, any degree of freedom may be incorporated into the gantry  48  and detector  46 .  
         [0034]    [0034]FIGS. 10-11 show another embodiment of the present invention. Nuclear imaging system  100  includes gantry  102 , detector  104  and patient support  106 . The gantry  102  includes a base unit  108  and an armature  110 . The base unit  108  may move toward and away from the patient support  106 . The first end of  112  of the armature  110  is mounted to the base  108  such that the armature  110  may rotate. The second end  112  of the armature  110  is mounted to the detectors  104  such that the detectors  104  may also rotate. These three freedoms of movement allow the detectors  104  to be placed at any needed height and distance from the patient.  
         [0035]    The detector  104  is shown including a detector  1114  and a detector  116 . This allows both better resolution than that of a single detector. Moreover, coincidence imaging becomes possible.  
         [0036]    The patient support  106  itself includes a base  116 , a pivot  118 , a Y-beam support  120 , and a patient chair  122 . The patient chair  122  may rotate about pin  118 . The chair  122  includes a contoured back  124  and a contoured seat  126 . Underneath the contoured seat  126  is contoured seat support  128 .  
         [0037]    [0037]FIGS. 10-11 show the patient chair  122  in a loading position. FIG. 12 shows the patient chair  122  in an imaging position with a patient  130  outlined to clarify the operation of the nuclear imaging system  100 . The patient region  132  is shown as the patient&#39;s cardiac region, a very common region to image. However, any region of the patient could be imaged in the same way as described herein.  
         [0038]    In the imaging position, as opposed to the loading position, the patient&#39;s feet  134  are level with the patient&#39;s cardiac region  132 . This is often advantageous in imaging a cardiac region.  
         [0039]    [0039]FIG. 14 shows a patient  140 , shorter than patient  130 , in an imaging position in patient chair  122 . The difference between FIG. 12 and FIG. 13 illustrates a direction of freedom of movement of the chair  122 . In order to place patient region  142  in the filed o view of the detectors  14 , the contoured seat  126  has been moved up relative to the head of patient  140 . Thus, patients of different size may be moved up and down to allow the imaging of the appropriate patient region. The seat support  128  may contain a motor or actuator in order to move the patient set  126 .  
         [0040]    Each of the above embodiments allows a patient to be loaded into a patient support in a loading position and then imaged in a patient support in an imaging position. This is advantageous in allowing for optimum loading ease and minimum loading time, while allowing for an optimum imaging position for image quality.  
         [0041]    The construction of the embodiments shown in FIGS. 3-12 by techniques and using materials that are well known in the art of nuclear medicine scanner systems, and imaging systems in general.  
         [0042]    The patient support and imaging systems contemplated herein above may be applied beyond the nuclear medicine modality to other imaging modalities, such as Magnetic Resonance imaging (MRI) and Computerized Tomography (CT), in cases where these modalities are using an seated imaging position different from an easily loaded position of a patient support.  
         [0043]    As these and other variations and combinations of the features discussed above can be utilized, the foregoing description of the preferred embodiments should be taken by way of illustration rather than by limitation of the invention set forth in the claims.