Abstract:
A mobile detector system for use in the detection of radiation photons. The detector system includes an exterior casing, having an internal area. The internal area has an interior periphery and an exterior periphery, at least one rail, at least one mobile camera, that is movably mounted on the at least one rail, and at least one motor. The motor drives at least one mobile camera, and the at least one mobile camera is movable along at least one rail within the exterior casing, to a plurality of radiation receiving positions.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to a mobile camera implementation for a medical imaging device such as a gamma camera, and more particularly a device having fully enclosed one or more camera detectors that move within the device housing on rails. 
         [0003]    2. Background Discussion 
         [0004]    Single photon emission computed tomography (SPECT) imaging is performed by using a gamma camera to acquire image or projection data from multiple angles with respect to a patient. The data is then sent to a computer that applies a tomographic reconstruction algorithm to the multiple projections, yielding a 3D dataset, which can be used to generate tomographic images for display on a display device. 
         [0005]    To acquire SPECT images the gamma camera is rotated around the patient with projections being acquired at defined points during the rotation, typically every 3-6 degrees. In most cases, a full 360 degree rotation is used to obtain an optimal reconstruction. The time taken to obtain each projection is also variable, but 15-20 seconds is typical giving a total scan time of 15-20 minutes. 
         [0006]    Multi-headed gamma cameras can provide accelerated acquisition, e.g. a dual headed camera can be used with heads spaced 180 degrees apart, allowing 2 projections to be acquired simultaneously, with each head only requiring 180 degrees of rotation. Triple-head cameras with 120 degree spacing are also used. 
         [0007]    Gated acquisitions are possible with SPECT, just as with planar imaging techniques such as multiple gated acquisition scans (MUGA). Cardiac gated myocardial SPECT can be used to obtain quantitative information about myocardial perfusion during the cardiac cycle, thickness and contractility of the myocardium and allow calculation of left ventricular ejection fraction, stroke volume, and cardiac output. 
         [0008]    Computer tomography (CT) scanners use a fan shaped beam of x-rays that is directed to an array of detectors that are fixed in position relative to the x-ray source. In some models of CT devices the images are acquired by a “translate-rotate” method in which the x-ray source and the detector in a fixed relative position move across the patient followed by a rotation of the x-ray source/detector combination (gantry) by one degree. In other models, instead of a row of detectors that move with the X-ray source, a stationary 360 degree ring of detectors is provided. The fan shaped x-ray beam is rotated around the patient in a non-fixed relationship with respect to the stationary detectors. 
         [0009]    Ultrasonography is a useful ultrasound-based medical imaging technology used for medical diagnostics. In addition to its diagnostic value, ultrasonography can be used to treat benign and malignant tumors and other disorders through focused ultrasound surgery (FUS) or high intensity focused ultrasound (HIFU). 
         [0010]    Positron emission tomography (PET) is a nuclear medicine medical imaging technique that produces three dimensional images using a radioactive tracer isotope, and is based on the physical phenomenon whereby annihilation of a positron by collision with an electron results in the simultaneous emission of two gamma photons traveling in 180 degree opposed directions. The simultaneously emitted photons are detected by a pair of 180 degree opposed detectors within the camera unit, by detecting coincidence events. 
         [0011]    The devices required for the above medical applications are generally large and extremely expensive. Some of the smaller devices run on gantry systems that are open exposing the patient to the moving cameras and mechanics. The size and/or or movement of the devices during the procedure can be intimidating to a patent, adding stress to an already stressful situation. To date, a simple enclosing of the gantry to eliminate motion is possible but sub-optimal for patient positioning. Additionally, enclosing the detector heads is costly, as the detector heads are usually suspended from a gantry or from an arm where the motion of the detectors is enabled by various trunions. 
       SUMMARY OF THE INVENTION 
       [0012]    The present invention provides a variety of advances and improvements over, among other things, the prior art systems and methods, by providing an enclosed mobile camera unit that can be constructed in various sizes to enable the technology to be used for heretofore difficult treatments. 
         [0013]    In one embodiment of the invention a detector system is used in the reception and translation of radioactive wavelengths. The detector system has an exterior casing including an internal area. The internal area houses one or more rails in a fixed position within the internal area, at least one mobile camera, and at least one motor for driving a mobile camera or cameras. 
         [0014]    In another embodiment of the invention, at least one mobile camera is movable along at least one rail within an exterior casing of a detector system. The camera is moved on a rail or rails to a plurality of radioactive wavelengths receiving positions. 
         [0015]    In a further embodiment of the invention, a detector casing is rotatably affixed to a chair. The detector casing houses a mobile camera that is movable along at least one rail within the casing of the detector system. The camera is moved on a rail or rails to a plurality of radioactive wavelengths receiving positions. 
         [0016]    In another embodiment of the invention, a detector casing is rotatably affixed to a stand. The detector casing houses a mobile camera that is movable along at least one rail within the casing of the detector system. The camera is moved on a rail or rails to a plurality of radioactive wavelengths receiving positions. 
         [0017]    In a further embodiment of the invention detector system includes a casing that houses a rail or rails that are at least partially flexible. 
         [0018]    In a still further embodiment of the invention a detector system includes a casing that houses a rail or rails that have a flexible region and a non-flexible region. 
         [0019]    In another embodiment of the invention a detector system includes a casing that houses a rail or rails that has flexible end portions and a rigid center portion. 
         [0020]    The above and/or other aspects, features and/or advantages of various embodiments will be further appreciated in view of the following description in conjunction with the accompanying figures. Various embodiments can include and/or exclude different aspects, features and/or advantages where applicable. In addition, various embodiments can combine one or more aspect or feature of other embodiments where applicable. The descriptions of aspects, features and/or advantages of particular embodiments should not be construed as limiting other embodiments or the claims. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The preferred embodiments of the present invention are shown by way of example, and not limitation, in the accompanying figures, in which: 
           [0022]      FIG. 1  is a cross-sectional top view of the detector system in accordance with the present invention; 
           [0023]      FIG. 2  is an end view of the mobile camera unit in accordance with the present invention; 
           [0024]      FIG. 3  is a side view of the mobile camera unit in accordance with the present invention; 
           [0025]      FIG. 4  is a top view of a rail having inflexible and flexible portions in accordance with the present invention; 
           [0026]      FIG. 5  is an end view of the mobile camera unit having a turret between the base and camera unit in accordance with the present invention; 
           [0027]      FIG. 6  is a cross-sectional top view of an embodiment of the detector system arranged for a CT scan in accordance with the present invention; 
           [0028]      FIG. 7  is a fragmentary cross-sectional side view of the housing of the detector system of  FIG. 6  in accordance with the present invention; 
           [0029]      FIG. 8  is a cross-sectional top view of the embodiment of  FIG. 6  arranged for a SPECT scan in accordance with the present invention; 
           [0030]      FIG. 9  is a cross-sectional top view of a U-shaped detector system in accordance with the present invention; 
           [0031]      FIG. 10  is a perspective view of the mobile camera used in the detector system of  FIG. 9  in accordance with the present invention; 
           [0032]      FIG. 11  is a cross-sectional top view of a circular detector system in accordance with the present invention; 
           [0033]      FIG. 12  is a cross-sectional side view of a C-shaped detector mounted on a stand in accordance with the present invention; 
           [0034]      FIG. 13  is a perspective view of a person in a chair incorporating the detector unit of  FIG. 1  in accordance with the present invention; 
           [0035]      FIG. 14  is a side view of an alternate chair incorporating the detector unit of  FIG. 1  in accordance with the present invention; and 
           [0036]      FIG. 15  is a top view of a detector unit dimensioned for use to treat oral disease in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0037]    While the present invention may be embodied in many different forms, a number of illustrative embodiments are described herein with the understanding that the present disclosure is to be considered as providing examples of the principles of the invention and that such examples are not intended to limit the invention to preferred embodiments described herein and/or illustrated herein. 
         [0038]    It is advantageous to define several terms before describing the invention. It should be appreciated that the following definitions are used throughout this application. 
       DEFINITIONS 
       [0039]    Where the definition of terms departs from the commonly used meaning of the term, applicant intends to utilize the definitions provided below, unless specifically indicated. 
         [0040]    For the purposes herein the term “arc, arced, arched” refers to a continuous section of any curve. 
         [0041]    For the purposes of the present invention, the term “detector” refers to any material or device capable of recognizing and translating the photons released by a radioactive material. This can include crystals, hyperpure germanium, solid-state detectors, etc. 
         [0042]    For the purposes of the present invention, the term “detector system” refers to any group of devices that enable the reception and translation of radioactive wavelength. This includes, but is not limited to, housings, mobile cameras, rails, detectors, stands, chairs, beds, etc. that are used in conjunction with nuclear medicine. 
         [0043]    For the purposes of the present invention, the term “mobile camera” refers to any type of unit that contains the components to receive and translate radioactive wavelengths. These components can include crystals, photomultipliers, collimators, solid state detectors, housings, electrical components, motors, etc. 
         [0044]    For the purposes of the present invention, the term “tomography” refers to any imaging technique using gamma rays that provides information presented as cross-sectional slices through the patient and can be reformatted and manipulated by computer as required. 
         [0045]    For the purposes of the present invention, the term “subject” refers to any living or non-living organism, as well as any organic or inorganic substance that be penetrated with any type of wavelength. 
         [0046]    For the purposes of the present invention, the term “flexible” refers to a structure that is capable of being bent or flexed, repeatedly without injury or damage, is responsive to change and is adaptable. 
         [0047]    For the purposes of this invention the term “trunion” refers to a cylindrical protrusion used for mounting an object to permit rotation. 
         [0048]    For the purposes of this invention, the term “turret” refers to any device that facilitates both horizontal and vertical movement. 
       Discussion of the Preferred Embodiments 
       [0049]    The disclosure relates to a mobile gamma camera enclosed in a stationary outer casing. The design is applicable to all detector technologies such as ultrasonography (US), solid-state detectors (e.g., CZT), photomultiplier tubes, etc., and collimation schemes such as parallel, focusing, multi-focusing, variable focusing and other adaptive collimation schemes that are mobile in accordance with the teachings herein. The applicability of technologies that are currently available, or come to be available in the future, will be evident to those skilled in the art. 
         [0050]    The detector system disclosed herein can be used to design various tomographic gamma cameras enabling SPECT, CT, PET or US for various applications, such as for cardiac, prostate, brain, extremities, and oral cancer imaging. Examples of these designs are illustrated and described hereinafter, however they are not intended to limit the scope of the invention and are to be considered examples of the potentials of the disclosed system. 
         [0051]    In one embodiment a gamma camera system is indicated generally as  100  in  FIGS. 1 ,  2  and  3 , wherein mobile gamma cameras  104  are self contained units that move on a pair of rails including inner rail  108  and outer rail  110  inside a housing  118 . The housing  118  can be part of an overall support structure or can be an independent, stand alone unit. Whether part of an overall support structure or independent unit, the housing  118 , the support structure and/or surrounding area, are preferably shielded to minimize detector exposure of radiation from extraneous sources. 
         [0052]    The mobile gamma camera  104 , in this embodiment, has four (4) supports  120 ,  122 , 124  and  126  (three of which are collectively shown in  FIGS. 2 and 3 ), that rigidly extend from the body  106  and contain wheel pairs  140  and  142 , and  146  and  148  respectively. Wheels  140  and  142  are maintained within the support  120  by shafts  141  and  143  respectively. Wheels  146  and  148  are maintained within support  122  by shafts  147  and  149  respectively. Support  124  and the corresponding support (referenced as  126 ) not visible in an end view, have identical wheel pairs. 
         [0053]    The wheel pairs  140  and  142  and  146  and  148  run on inner rail  108  and outer rail  110  and are powered either by individual motors or, more preferably by a single motor. The individual motors can be located in the supports  120 ,  122 ,  124  and  126  or in the body  106  of the mobile gamma camera  104 . If a single, geared motor is used, it can be placed in the body  106 . 
         [0054]    The gamma camera system  100  illustrated in  FIG. 1  incorporates a single mobile gamma camera  104 , however the number of mobile gamma cameras  104  is only limited by geometric considerations. The motion of the detector heads is then appropriately limited. 
         [0055]    The  108  and  110  rails can be rigid, flexible or segmented to provide both flexible and inflexible portions, as illustrated in  FIG. 4 . The advantage to the flexible, or partially flexible, rails is to achieve an optimally close track for a range of subject sizes. 
         [0056]    In  FIG. 4  the rail  400  is segmented with rigid ends  402  and  404  and flexible center  4506 . This configuration by way of example only and other combinations and configurations will be evident to those skilled in the art. 
         [0057]    Referring to  FIG. 5 , in some applications it is advantageous for the body  506  of the mobile gamma camera  500  to swivel or rotate in order to achieve optimal tomographic sampling. In the mobile gamma camera  500 , as illustrated in  FIG. 5 , a turret  560  is placed between the body  506  and the wheelbase  510 . The body  506  can swivel vertically about 10° to 20°, and can translate perpendicular to the detector face. On the horizontal plane the body  506  can swivel up to 360° and the amount of horizontal movement required will be evident to those skilled in the art. In the embodiment illustrated herein, support plates  562  and  564  have been added to provide additional reinforcement. Other methods of providing either horizontal or vertical rotation or both will be known to those skilled in the mechanical arts. 
         [0058]    In  FIGS. 6 ,  7 , and  8 , an alternate embodiment is illustrated using the track system disclosed herein for a scanning system using a radiation source  602  that is affixed to a slip ring  616 . The opposing side of the slip ring  616  has a pair of rails  620  that carry detectors  608 . The detectors  608  can be positioned along the rails  620  in either a stationary configuration or they can rotate around the rails  620 . 
         [0059]    In  FIG. 6 , the detectors  608  are stationary and within the field of view  626  of the radiation source  602  while the entire slip ring  616  remains stationary. This configuration can be used for CT scans.  FIG. 7  is a side view of  FIG. 6 . 
         [0060]    In  FIG. 8 , the configuration can be for a SPECT scan wherein the detectors  608  are shown dispersed and capable of rotating around the slip ring  616 , in the direction of arrows  610 . 
         [0061]    In  FIGS. 9 and 10  the detector system  900  is a U-shaped housing having a single rail  916 , although double rails as in previous embodiments also can be used. The mobile camera unit  930  contains a detector  934  within a housing configured to move on the rail  916 . On the portion of the housing facing the subject, the housing has a transmission source  938  with swivel shielding that enables the directing of the field of emission impinging on the detector face. 
         [0062]    The radiation source  938  for the U-shaped detector system  900  can be isotopes, or x-ray tubes or cold x-rays. The movement of the mobile camera units  930  will be dependent upon the type of detector  934  being used. 
         [0063]    In the embodiment illustrated in  FIG. 11  the housing  1102  is circular with the subject  1130 , positioned in the center. Within the housing  1102 , there is a dual rail track  1106  that carries the detector containing mobile cameras  1114  and  1110 . Alternatively, one of the mobile cameras, for example  1114 , can contain a radiation source while the other mobile camera  1110  can contain a collimator and detectors. 
         [0064]    In  FIG. 12 , the detector system  1200  is positioned vertically on a stand  1206  to enable the detector system to be positioned on either side of the subject. In this illustration there is a single rail  1210  that carries the mobile camera  1214  within the housing  1218 . Dual rails and multiple mobile cameras as discussed in conjunction with other embodiments can also be used in this embodiment. This embodiment enables the detector system  1200  to be beneficial for use in the lower body as well as for vaginal and rectal probes. 
         [0065]    In  FIG. 13  the detector unit  1300  consists of a chair  1304  designed to maintain the patient  1308  in the upright position. The detector housing  1314  is connected to the chair  1304  in a rotatable manner to enable the patent  1308  to sit in the chair  1304  with the detector housing  1314  being rotated and secured into place over the patient&#39;s  1308  chest. 
         [0066]    The chair  1404  in detector unit  1400  of  FIG. 14  is designed to rotate upon base  1408  to enable the patient  1416  to be placed in any one of multiple positions. As described above, the detector housing  1412  rotates to enable the patient  1416  to lie on the chair  1404  prior to the housing  1412  being locked in place. 
         [0067]    In  FIG. 15  a detector unit  1500  is dimensioned for use to image oral cancer, an often-difficult area to treat due to the sizing requirements. The interior arc  1504  of the detector unit  1500  is dimensioned to bring the mobile camera  1506  in appropriate proximity to the patent&#39;s head  1502 . The mobile camera  1506  runs on rails  1508  as described heretofore. 
       BROAD SCOPE OF THE INVENTION 
       [0068]    While illustrative embodiments of the invention have been described herein, the present invention is not limited to the various preferred embodiments described herein, but includes any and all embodiments having equivalent elements, modifications, omissions, combinations (e.g., of aspects across various embodiments), adaptations and/or alterations as would be appreciated by those in the art based on the present disclosure. The limitations in the claims (e.g., including that to be later added) are to be interpreted broadly based on the language employed in the claims and not limited to examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive. For example, in the present disclosure, the term “preferably” is non-exclusive and means “preferably, but not limited to.” In this disclosure and during the prosecution of this application, means-plus-function or step-plus-function limitations will only be employed where for a specific claim limitation all of the following conditions are present in that limitation: a) “means for” or “step for” is expressly recited; b) a corresponding function is expressly recited; and c) structure, material or acts that support that structure are not recited. In this disclosure and during the prosecution of this application, the terminology “present invention” or “invention” may be used as a reference to one or more aspect within the present disclosure. The language present invention or invention should not be improperly interpreted as an identification of criticality, should not be improperly interpreted as applying across all aspects or embodiments (i.e., it should be understood that the present invention has a number of aspects and embodiments), and should not be improperly interpreted as limiting the scope of the application or claims. In this disclosure and during the prosecution of this application, the terminology “embodiment” can be used to describe any aspect, feature, process or step, any combination thereof, and/or any portion thereof, etc. In some examples, various embodiments may include overlapping features. In this disclosure, the following abbreviated terminology may be employed: “e.g.” which means “for example.”