BACKGROUND OF THE INVENTION

Field of the Art

The disclosure as detailed herein is in the technical field of medicine. More specifically, the present disclosure relates to the technical field of fluoroscopic imaging.

Discussion of the State of the Art

Modern medical facilities, such as hospitals or emergency care facilities, are often large and complex organizations. A medical facility may be organized into various departments or branches that specialize in a particular type of patient care or expertise. For example, a medical facility may have a radiology department that handles various medical imaging tasks such as computed tomography (CT) systems, radiation systems (including both conventional and digital or digitized imaging systems), Magnetic Resonance Imaging (MRI) systems, Positron Emission Tomography (PET) systems, ultrasound systems, nuclear medicine systems, and the like. Such systems provide invaluable tools for identifying, diagnosing, and treating physical conditions and greatly reduce the need for surgical diagnostic intervention. In many instances, these modalities complement one another and offer the physician a range of techniques for imaging particular types of tissue, organs, physiological systems, and so forth. However, patients requiring radiation, for example, must often be transported to the radiology department or even a separate and geographically distant imaging center. This can present additional delays, costs, and inconveniences to the patient and the practitioners.

Digital imaging systems are becoming increasingly widespread for producing digital data that can be reconstructed into useful radiographic images. In one application of a digital imaging system, radiation from a source is directed toward a subject, typically a patient in a medical diagnostic application, and a portion of the radiation passes through the subject and impacts a detector.

A number of devices have been conceived to address the needs to align the X-ray source to the detector of portable and mobile x-ray imaging systems, including developments in portable and mobile units, detectors, and related digital imaging features. For example, US Publication No. 2008/7344305B2 invented by Kuzmanovic, et al, discloses a method and system are providing for performing X-ray diagnostic imaging using a camera image controlled to image a field of view (FOV), that is substantially coincident and coplanar with a radiation footprint or FOV of an X-ray beam radiated towards a patient under examination. The method and system includes acquiring a camera image with a collimated FOV to an X-ray beam FOV before X-ray imaging a patient, displaying the camera image and adjusting the collimation and patient positioning to define the X-ray beam FOV based on the displayed camera image before X-ray imaging the patient. The use of a video camera instead of a light source and mirror to provide a means to visualize the collimated area of the x-ray beam exists in the prior art as described by Kuzmanovic (U.S. Pat. No. 7,344,305 B2). Kuzmanovic teaches the use of a retractable video camera that can be inserted into the central axis of the x-ray beam to create an image through the collimator blades. This image when displayed on a monitor shows the FOV of the collimated X-ray beam area of the patient being exposed. The operator can then adjust the collimator blades to provide the desired area of exposure using the image captured by the camera in real-time. Once the desired area is obtained, the camera is retracted from the beam and an x-ray image can be acquired.

The use of a retractable video camera positioned on the central axis of the x-ray beam does have the advantage that the image it acquires is defined by the position or aperture of the collimator blades, such the acquired images displayed on a monitor are substantially coincident and coplanar with a radiation footprint or FOV of the collimated X-ray beam radiated towards a patient under examination. The problem or disadvantage with this approach is that the user only has the collimated FOV provided by the camera collimated image to assist with visually positioning the radiation beam to the anatomic region being examined. The light source/mirror provides the user the benefit of a projected light field image displayed on the patient that is substantially coincident and coplanar with a radiation footprint or FOV of the collimated X-ray beam radiated towards a patient under examination. The user can view the projected light image and position the lighted image to the region of interest (ROI) with the normally used patient body landmarks to position the projected light field to the anatomic region being examined.

Further, despite advances in the art, there remain significant shortcomings in existing systems used for mobile diagnostic imaging. Current mobile radiography/fluoroscopic imaging systems are cumbersome and expensive. These mobile systems normally incorporate a fixed, mechanical C-arm, or other mechanical configuration which connects the radiation source and the detector to one another, in order to mechanically fix the detector relative to the Radiation source to prevent misalignment outside of normally government-regulated, pre-determined tolerances. In addition, the spatial location of the detector is not always known relative to the Radiation source, as is the case in fixed, permanent digital radiography/fluoroscopic (DR) imaging systems. Especially when the subject to be imaged is very fragile or largely immobile, the need continues to exist for mobile systems which comply with applicable regulations.

Further, systems known in the art use of a retractable video camera positioned on the central axis of the x-ray beam to display acquired images on a monitor that are substantially coincident and coplanar with a radiation footprint or FOV of the collimated X-ray beam radiated towards a patient under examination. A disadvantage with this approach is that the user only has the collimated FOV provided by the camera collimated image to assist with visually positioning the radiation beam to the anatomic region being examined. A further disadvantage of systems known in the art comprising a light source and mirror system is that they must provide protection for a larger area with metal barriers (that is, the larger area to accommodate the light source and mirror) in the t. A larger head unit results in a heavy top portion of a portable radiation system creating high center of gravity resulting in a cumbersome and potentially dangerous situation when in movement.

What is needed in the art are systems and methods for providing an image that is substantially within the same FOV of the patient as the calculated active area of the detector and an overlay shaded area within the image that is substantially within the same FOV of the radiation beam with the shaded area representing a collimated area of the collimator based on shutter position, the shaded area further operable to change position based on interaction from an interactive display and have the collimator shutters respond to changes in position while creating an environment whereby a smaller area within the head unit is present, to reduce the amount and weight of the metal barrier.

SUMMARY OF THE INVENTION

Accordingly, the inventor has conceived and reduced to practice, in a preferred embodiment of the invention, an X-ray imaging system comprising, at least, an x-ray source, an x-ray detector, and a collimator assembly. The collimator assembly comprises, at least, a computer, a display, a camera, an x-ray source to object (patient) measuring device to measure source to object distance (SOD), and a plurality of metallic barriers controllable via the network, with an adjustable aperture used to manipulate a size, shape, and location of X-ray beams, thereby also reducing the volume of irradiated tissue in the patient. The collimator may comprise computer-controlled motorized shutters to define a collimated area that admits radiation into the region defined by the adjustable beam-defining components of the collimator of an X-ray apparatus. In some embodiments, the plurality of metallic barriers may be a fixed cone, or a cone comprised of movable plates.

Filtration and collimation of the X-ray beam are important safety measures. In a preferred embodiment, the camera may provide an image that is substantially within the same FOV of the patient as the calculated active area of the detector. Further, the camera may provide indicia (for example, overlay a shaded area. Hereinafter the indicia also referred to as shaded area) within the camera image that represent substantially the same FOV as the shutter aperture size and location (also referred to herein as collimated area).

The computer may use the known position and size of the shutter aperture and the SOD information to calculate and adjust a size and position of the shaded area within the camera image of patient with respect to the active area of detector. By viewing the camera images, the operator or clinician (also referred to herein as user) may determine directly, particularly during pre-examination alignment, whether the radiation beam is aligned to the anatomic region that will be irradiated. That is, the camera provides a FOV of the radiation beam overlayed on an image of the patient, wherein the viewer immediately knows if the FOV has changed, or needs to be changed by patient and/or collimator realignment, etc. The method of examination in accordance with an embodiment of the invention is different from conventional patient or alignment imaging, and diagnostic imaging methods. By use of the inventive system and method, the clinician may realize improved patient through-put, reduced patient and/or clinician exposure to unnecessary X-ray exposure, unnecessary discarded images and reduced dose levels overall due to improved collimator adjustment whilst complying with governmental regulations to provide means for visually defining the perimeter of the x-ray field.

According to a preferred embodiment of the invention, the inventive x-ray imaging system comprises an x-ray source for generating and controlling an X-ray beam radiated towards a patient under examination. The X-ray source comprises an X-ray tube, and x-ray collimator assembly. In a preferred embodiment, the collimator assembly comprises, at least, a camera, a computer, a distance measuring device (SOD), and an interactive visual display. The camera may be arranged to image with an adjustable field of view (FOV) at a physical position of the X-ray beam and the patient that is substantially coincident with and at least as large as a maximum radiation pattern footprint or FOV of the radiated X-ray beam. Both the radiated beam, and camera FOV are shaped and/or limited by the collimator computer. The system comprises an X-ray imaging device arranged for receiving the X-ray beam after it has passed through the patient and acquiring latent image frames of a region of interest (ROI) within the patient's anatomy. One or more computers communicatively connected to the X-ray source, X-ray imaging device and collimator computer controls latent image frame acquisition and post-acquisition processing, including controlling the X-ray tube, x-ray imaging device and provides data to the collimator computer to adjust the position and size of the radiation beam FOV and the position and size of the shaded area within the camera image. The image processing chain comprising an image processor that is coupled to the system computer receives the latent image frames from the X-ray imaging device for processing and a display device coupled to the image processing chain displays post-processed image frames as an X-ray diagnostic image of the ROI.

The camera images may be displayed on the visual display during normal imaging operation, or display camera images only when the X-ray system is in a pretest or physical set-up operation, wherein a position and size of the collimator aperture is arranged to constrict the FOV of the X-ray beam and camera shaded area are substantially similarly. In a preferred embodiment, the camera is a video capable camera, and most preferably that the video camera is miniaturized. Of course, a focusing system that is included with the camera to focus the camera FOV such as the available area that could be exposed when the collimator shutters are fully opened and the shaded area within the FOV.

