US 20080212743 A1
An x-ray scanning imaging apparatus with a rotatably fixed generally O-shaped gantry ring, which is connected on one end of the ring to support structure, such as a mobile cart, ceiling, floor, wall, or patient table, in a cantilevered fashion. The circular gantry housing remains rotatably fixed and carries an x-ray image-scanning device that can be rotated inside the gantry around the object being imaged either continuously or in a step-wise fashion. The ring can be connected rigidly to the support, or can be connected to the support via a ring positioning unit that is able to translate or tilt the gantry relative to the support on one or more axes. Multiple other embodiments exist in which the gantry housing is connected on one end only to the floor, wall, or ceiling. The x-ray device is particularly useful for two-dimensional multi-planar x-ray imaging and/or three-dimensional computed tomography (CT) imaging applications
1. An imaging apparatus comprising:
a generally O-shaped gantry ring;
a support structure; and
a ring positioning unit that secures the gantry ring to the support structure in a cantilevered manner, and positions the gantry ring relative to the support structure.
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22. A method for imaging an object with an imaging system having a substantially O-shaped gantry secured to a support structure in a cantilevered fashion by a ring positioning unit, comprising:
positioning the object within a central opening of the generally O-shaped gantry;
operating the ring positioning unit to position the gantry at a predetermined position and orientation relative to the support structure; and
obtaining an image of the object.
28. An x-ray imaging apparatus comprising:
a generally O-shaped gantry ring having a radiation source and a detector array for obtaining two-dimensional or three-dimensional images of an object located within the gantry ring; and
a mobile support that supports the gantry in a cantilevered fashion.
This application is a continuation of U.S. application Ser. No. 10/459,405, filed Jun. 11, 2003, which claims the benefit of U.S. Provisional Application No. 60/388,063, filed Jun. 11, 2002, the entire teachings of which are incorporated herein by reference.
Healthcare practices have shown the tremendous value of three-dimensional imaging, mainly as a diagnostic tool in the Radiology Department. Other areas of care, including the operating room, intensive care departments and emergency departments, rely on two-dimensional imaging (fluoroscopy, ultrasound, 2-D mobile X-ray) as the primary means of diagnosis and therapeutic guidance. This is mainly due to the cost, size, and expertise required to operate traditional three-dimensional devices. Moreover, radiologic quality CT scanners have been designed to maximize image quality at the expense of mobility. Truly practical and mobile imaging solutions for “non-radiology departments” capable of performing both 2D and 3D imaging in the same device have yet to be developed. Previous attempts simply do not address the true need, which is to maintain a sizable volume while meeting a level of expected image quality. In the past, there have been two types of devices proposed to address this need. One type of device uses a mobile C-arm and spins it around the anatomy, such as the Siremobil Iso-C3D system from Siemens AG. These C-arm based attempts have a limited field of view, are procedurally cumbersome and have an inherent limit to the image quality.
Others have attempted to make a fixed-bore CT mobile, such as the device described in Butler W. E. et al, A Mobile CT Scanner with Intraoperative and ICU Application, 1998. (http://neurosurgery.mgh.harvard.edu/mobileCT.htm). However, these so-called “mobile CT scanners” are characterized by the elevated dosing level of a traditional fixed CT scanner, they are difficult to maneuver, and they are incapable of performing 2D imaging when that is all that is needed.
In general, the fluoroscopic C-arm attempts meet the criteria of mobility and flexibility, but fall short on image quality and image volume. The “mobile CT scanner” attempts meet the criteria of image volume and quality, but fail to address the practical issues of usability and cost. Additionally, state of the art CT scanners are incapable of translating and tilting in the same fashion of mobile fluoroscopy systems.
A truly mobile and practical solution for ‘non-radiology department’ 3-D imaging also capable of performing 2D imaging does not yet exist. This is mainly due to the fact that current tomographic scanners are not mobile in a practical manner. The inability to move a CT scanner with the same degrees of freedom of mobile C-arms has hindered the acceptance and use of mobile three-dimensional imaging. This has limited the value of three-dimensional computed tomographic imaging to areas mainly as a diagnostic tool in the Radiology Department.
There is a need for a mobile CT scanner for use in the operating room, intensive care unit, emergency room and other parts of the hospital, in ambulatory surgery centers, physician offices, and the military battlefield, which is truly mobile and capable of performing both 2D and 3D x-ray imaging.
The present invention is directed to an imaging apparatus comprising a generally O-shaped gantry ring having an x-ray source and a detector. The gantry ring is rigidly or movably secured on one side of the ring to a support structure, such as a mobile cart, a wall, a ceiling, a floor, or a patient table, in a cantilevered fashion.
According to one aspect, a positioner assembly can secure the gantry ring to the support structure in a cantilevered fashion, the positioner assembly permitting the gantry to translate in at least one direction, and/or rotate around at least one axis, relative to the support structure.
According to one aspect, the x-ray source is contained inside the gantry ring, opposed to a detector array. The x-ray source (and optionally the detector) can rotate around the inside of the gantry ring, preferably through a full or partial 360 degree scan around the interior of the gantry. The imaging apparatus is particularly advantageous for medical imaging applications, including 3D computerized tomographic (CT) imaging and 2D x-ray radiographic scanning, as well as other medical, scientific, and industrial applications.
According to another aspect, a method for imaging an object with an imaging system having a substantially O-shaped gantry secured to a support structure in a cantilevered fashion by a ring positioning unit, comprises positioning the object within a central opening of the generally O-shaped gantry; operating the ring positioning unit to position the gantry at a predetermined position and orientation relative to the support structure; and obtaining an image of the object.
The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.
A description of preferred embodiments of the invention follows.
The mobile cart 12 of
The mobile cart 12 preferably also includes a display system 60, such as a flat panel display, for displaying images obtained by the x-ray scanner. The display can also include a user interface function, such as a touch-screen controller, that enables a user to interact with and control the functions of the scanning system. In certain embodiments, a user-controlled pendant or foot pedal can control the functions of the scanning system.
It will be understood that one or more fixed units can also perform any of the functions of the mobile cart 12.
According to one aspect, the x-ray scanning system of the invention can be used to obtain two-dimensional planar or three-dimensional computerized tomographic (CT) x-ray images of an object, such as a patient. In the embodiment shown in
The x-ray source 13 is able to rotate around the interior of the gantry 11 in a continuous or step-wise manner so that the x-ray beam can be projected through the object, and through a common isocenter, at various angles over a partial or full 360 degree rotation. The detector array is also rotated around the interior of the gantry, in coordination with the rotation of the x-ray source, so that for each projection angle of the x-ray source, the detector array is positioned opposite the x-ray source on the gantry. The apparatus is thus able to obtain high-quality x-ray images of the targeted object in any projection plane over a partial or full 360 degree rotation.
The gantry positioning unit 20 can be controlled manually, or, in a preferred embodiment, it is a motorized system that can be moved electro-mechanically to a desired position. A computerized motion control system can be attached to motorized components of the positioner and one or more discreet positions and orientations of the gantry may be stored in the computer's memory. During operation of the x-ray scanner, pre-defined gantry positions and orientations may be returned to quickly and easily.
Referring now to
According to one aspect, each of the positioner assemblies 305, 307, 309, 311 comprising the ring positioning unit 20, includes a mechanism for providing position feedback information to its respective servomotor in order to enable precise positioning of the gantry along each degree of translational or rotational motion. For example, referring to
Turning now to
The x-ray imaging systems and methods described herein may be advantageously used for two-dimensional and/or three-dimensional x-ray scanning. Individual two-dimensional projections from set angles along the gantry rotation can be viewed, or multiple projections collected throughout a partial or full rotation may be reconstructed using cone or fan beam tomographic reconstruction techniques. This invention could be used for acquiring multi-planar x-ray images in a quasi-simultaneous manner, such as described in commonly-owned U.S. patent application Ser. No. 10/389,268, filed on Mar. 13, 2003, the entire teachings of which are incorporated herein by reference.
The detector arrays of the present invention include two-dimensional flat panel solid-state detector arrays. It will be understood, however, that various detectors and detector arrays can be used in this invention, including any detector configurations used in typical diagnostic fan-beam or cone-beam imaging systems, such as C-arm fluoroscopes, or single-sliced or multi-sliced CT scanners, or mobile and fixed-room floroscopy devices which utilize image intensifier technology. A preferred detector is a two-dimensional thin-film transistor x-ray detector using scintillator amorphous-silicon technology.
For large field-of-view imaging, the detector array can be translated to, and acquire imaging data at, two or more positions along a line or arc opposite the x-ray source, such as via a motorized detector rail and bearing system. Examples of such detector systems, and associated beam positioning systems, are described in commonly owned U.S. patent application Ser. No. 10/392,365, filed Mar. 18, 2003, the entire teachings of which are incorporated herein by reference.
In yet another aspect, the O-shaped gantry can include a segment that at least partially detaches from the gantry ring to provide an opening or “break” in the gantry ring through which the object to be imaged may enter and exit the central imaging area of the gantry ring in a radial direction. An advantage of this type of device is the ability to manipulate the x-ray gantry around the target object, such as a patient, and then close the gantry around the object, causing minimal disruption to the object, in order to perform x-ray imaging. Examples of “breakable” gantry devices for x-ray imaging are described in commonly-owned U.S. patent application Ser. No. 10/319,407, filed Dec. 12, 2002, the entire teachings of which are incorporated herein by reference.
While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. For instance, although the particular embodiments shown and described herein relate in general to x-ray imaging applications, it will further be understood that the principles of the present invention may also be extended to other medical and non-medical imaging applications, including, for example, magnetic resonance imaging (MRI), positron emission tomography (PET), single photon emission computed tomography (SPECT), ultrasound imaging, and photographic imaging.
Also, while the embodiments shown and described here relate in general to medical imaging, it will be understood that the invention may be used for numerous other applications, including industrial applications, such as testing and analysis of materials, inspection of containers, and imaging of large objects.