Patent Number: 
Section: claims

1. A portable radiographic imaging apparatus for fluoroscopy comprising:a wheeled transport frame;a C-shaped support arm mounted on the frame;radiation sources attached to a fixed end of the support arm;a radiation detector attached to a retractable end of the support arm when the retractable end is extended outward from the support arm, the retractable end opposite the fixed end, wherein the radiation sources comprise two or more radiation sources that are individually energizable to emit a radiation beam toward the retractable end, the imaging detector is removable from the retractable end for free-standing operation, and wherein the retractable end is configured to retract into an interior space of the support arm;a rotatable switching actuator that is configured to replace one of the radiation sources by simultaneously rotating into position a new radiation source while rotating out of position said replaced one of the radiation sources and to align the radiation beams from each of the new and replaced radiation sources along the same optical path;a temperature sensor that provides a signal indicative of a temperature near an energized radiation source; anda processor configured to monitor the signal from the temperature sensor, and to control energization of the two or more radiation sources according to the monitored signal. 2. The portable radiographic imaging apparatus for fluoroscopy according to claim 1, further comprising a collimator, wherein the processor is configured to detect an orientation of the radiation detector relative to one of the radiation sources and to adjust an aperture of the collimator to shape the radiation beam for incidence on a predetermined area of the radiation detector. 3. The portable radiographic imaging apparatus of claim 1, further comprising a collimator having an aperture to shape an x-ray beam emitted by the radiation sources, the collimator including a plurality of collimator blades to define a non-rectangular shape of the aperture. 4. The portable radiographic imaging apparatus of claim 1, wherein the radiation detector is configured to capture radiographic images at a rate greater than one image per second. 5. The portable radiographic imaging apparatus of claim 1, wherein the processor is further configured to wirelessly communicate with the radiation detector, and wherein the radiation detector comprises a wireless transmitter to transmit radiographic images to the processor. 6. The portable radiographic imaging apparatus of claim 1, wherein the retractable end comprises jointed sections that telescope inward and outward, and wherein the detector and radiation source cooperate to expose and acquire radiographic image data according to a synchronization signal. 7. The portable radiographic imaging apparatus of claim 1, wherein the retractable end is configured to retract automatically when the radiation detector is removed therefrom. 8. A portable radiographic imaging apparatus comprising:a transport frame having wheels to rollably transport the portable radiographic imaging apparatus;a C-shaped support arm mounted on the transport frame;radiation sources attached to a fixed end of the support arm;a radiation detector attached to a retractable end of the support arm, the retractable end of the support arm opposite the fixed end of the support arm; anda rotatable actuator attached to the fixed end of the support arm, the rotatable actuator configured to replace one of the radiation sources by simultaneously rotating into an imaging position a new radiation source while rotating out of the imaging position the replaced one of the radiation sources, and to align the radiation beams emitted from each of the new and replaced radiation sources along the same optical path when in the imaging position. 9. The portable radiographic imaging apparatus of claim 8, wherein the radiation sources comprise two or more radiation sources that are individually energizable to emit a radiation beam toward the retractable end. 10. The portable radiographic imaging apparatus of claim 8, wherein the imaging detector is removable from the retractable end for free-standing operation. 11. The portable radiographic imaging apparatus of claim 10, wherein the retractable end is configured to retract into an interior space of the support arm. 12. The portable radiographic imaging apparatus of claim 8, further comprising a temperature sensor configured to provide a signal indicative of a temperature near an energized radiation source. 13. The portable radiographic imaging apparatus of claim 12, further comprising a processor configured to monitor the signal from the temperature sensor, and to control activation of the radiation sources in response to the monitored signal. 14. The portable radiographic imaging apparatus of claim 8, further comprising a collimator having an adjustable aperture to shape the radiation beams emitted from the radiation sources for incidence on a predetermined area of the radiation detector. 15. The portable radiographic imaging apparatus of claim 14, wherein the collimator comprises individual collimator blades configured to define a non-rectangular shape of the adjustable aperture. 16. The portable radiographic imaging apparatus of claim 8, wherein the radiation detector is configured to capture radiographic images at a rate greater than one image per second. 17. The portable radiographic imaging apparatus of claim 16, wherein the radiation detector comprises a wireless transmitter to transmit the captured radiographic images wirelessly during free-standing operation. 18. The portable radiographic imaging apparatus of claim 8, wherein the retractable end of the support arm comprises telescoping extendable and retractable sections that extend inward and outward. 19. A method of operating a portable radiographic imaging apparatus, the method comprising:attaching an adjustable support arm to the portable radiographic imaging apparatus;attaching radiation sources to a first end of the support arm;transporting the portable radiographic imaging apparatus to a position adjacent a patient in a bed using wheels attached to the portable radiographic imaging apparatus;positioning a radiation detector on one side of the patient;adjusting an imaging position of a first one of the radiation sources to align a central axis of a radiation beam emitted by the first one of the radiation sources toward the detector; andsimultaneously rotating into the imaging position a second one of the radiation sources while rotating out of the imaging position the first one of the radiation sources, and aligning a central axis of a radiation beam emitted by the second one of the radiation sources with the central axis of the radiation beam emitted by the first one of the radiation sources, wherein the first and second radiation sources are rotated about a common axis. 20. The method of claim 19, further comprising attaching the radiation detector to a second end of the support arm opposite the first end of the support arm before the step of positioning the radiation detector.