Patent Description:
Mobile x-ray systems are of particular value in intensive care unit (ICU) and other patient care environments where timely acquisition of a radiographic image is important. Because it can be wheeled around the ICU or other hospital area and brought directly to the patient's bedside, a mobile x-ray system allows an attending physician or clinician to have recent information on the condition of a patient and helps to reduce the risks entailed in moving patients to stationary equipment in a radiological imaging department.

<CIT> discloses a mobile X-ray apparatus including a positionable X-ray tube assembly for alignment with a DR detector, a drive wheel, a base, an elevating column, and a telescopic arm which is rotatable into a direction perpendicular to a driving direction of said base. The apparatus is automatically controllable to drive along a patient table and the X-ray tube assembly is automatically height adjustable for alignment.

<CIT> discloses a brake assist system for patient handling equipment such as a patient bed. A wheel of the bed includes the brake assist system operated by a control unit which senses tilt of the handling equipment and applies partial breaking to the wheel when it is detected that the equipment is on a slope. It controls a maximum speed of the equipment down the slope and disengages the brake assist mechanism after detection that the equipment is on a horizontal surface.

The perspective view of <FIG> shows an example of a mobile radiography system <NUM> that may be employed for computed radiography (CR) and/or digital radiography (DR). A mobile radiography system <NUM> on wheels <NUM> enables transporting the mobile radiography system <NUM> by rolling the wheels <NUM> over a surface such as a floor. A base frame <NUM> includes a top surface <NUM> visible to an operator. The top surface <NUM> may include a display screen used for display of captured radiographic images, an interactive graphical user interface, and other alphanumeric data related to system status and readiness and/or instructions for an operator using the mobile radiography system <NUM>. The top surface <NUM> may include a control panel to allow data input by an operator, such as via a keyboard, a touch sensitive display screen, and a mouse. The operator may use the control panel <NUM> to control firing of an x-ray source <NUM> as well as related functions such as storing, processing, transmitting, modifying, and printing of a radiographic image captured by the mobile radiography system <NUM>, or to set numerical thresholds for controlling mobility and x-ray head deployment, as described herein. The wheels <NUM> may be free-wheeling or controlled by electric motor in response to operator input via the handle bar <NUM>, or a combination thereof. The handle bar <NUM> may also include squeezable handles or buttons to engage electronically controlled wheel brakes at the wheels <NUM>. A support arm, comprising a vertical base section <NUM> mounted to the base frame <NUM>, an extendable column section <NUM> extendable vertically relative to base section <NUM>, and a horizontally telescoping boom <NUM>, is used to support an x-ray head <NUM> attached to an end of the horizontal boom <NUM>. The vertical base section <NUM>, together with extendable column section <NUM>, is rotatable relative to the base frame <NUM> about vertical axis V. The extendable column section <NUM> may be extended vertically along axis V in a telescoping fashion relative to the base section <NUM> to raise or lower the x-ray head <NUM>. The raising and lowering of the extendable section <NUM> may be performed manually, such as by grasping the boom <NUM> and lifting/lowering it, or by motor control.

A central processing system <NUM> in base frame <NUM> provides an electronic control system that executes programmed logic functions for the mobile radiography system <NUM>, including motorized control of mobile radiography system <NUM> movement, such as control of a transport drive system <NUM> for driving the wheels <NUM>. The central processing system <NUM> may include electronic memory for storing programmable functions as described herein, which functions may include stored presets selectively input by an operator. Positioning of the x-ray head <NUM>, such as rotating the extendible column <NUM> about a vertical axis V, raising and lowering the boom <NUM>, and extending the telescopic boom <NUM> along a horizontal axis H may be performed manually. A column sensor <NUM> may detect and report data to the central processing system <NUM> representing a vertical distance that the extendable column section <NUM> is extended relative to the base section <NUM>. A base sensor <NUM> may transmit data to the processing system <NUM> indicating an angular position of the base section <NUM> and/or at positions therebetween, the extendable section <NUM> being relative to the base frame <NUM>. Using these vertical extension and angular rotational data, the central processing system <NUM> may determine whether the support arm is in a fully undocked (<FIG>) or fully docked (<FIG>) position.

The x-ray head <NUM> may include an x-ray source <NUM> and an attached collimator <NUM>, which x-ray head <NUM> may be attached to the extendable boom <NUM> and be rotatable about horizontal axis H. The extendible column section <NUM> may also be telescopically height adjustable along axis V. The electronic control provided by processing system <NUM> is in signal communication with the x-ray head <NUM> for controlling actuation and firing of the x-ray source <NUM> therein and adjusting an aperture size of the collimator <NUM>. The mobile radiography system <NUM> is shown in <FIG> in an undocked position whereby the support arm comprising base section <NUM>, extendable column section <NUM> and boom <NUM> is undocked and the x-ray head <NUM> is deployed to a maximum extension of the support arm.

Mobile radiography system <NUM> may include a rechargeable internal battery or other power source <NUM> disposed within, or coupled to, base frame <NUM>, and is used to provide power to various components of the mobile radiography system <NUM>, including a transport drive system <NUM> with motors electromechanically connected to drive the wheels <NUM> for facilitating motorized rolling movement of the mobile radiography system <NUM> to different sections or departments within a medical facility. Typically, the power source <NUM> is provided as a bank of multiple battery cells, such as lead-acid batteries. The processing system <NUM> may include dedicated logic processors for controlling various functions and displays, provide operator interface utilities and display imaging results, control wireless transmitters and detectors, adjustable columns, booms and other positioning facilities, including collimator <NUM> lights, the x-ray source <NUM>, and other functions. The handle <NUM> may be used for motorized steering control of the mobile radiography system <NUM> and may be coupled to the transport drive system <NUM> via processing system <NUM>. The handle <NUM> may be touch sensitive such as detecting an operator's pressure at right/left sides of the handle <NUM> to enable manually controlled motorized steering by electrically signaling the processing system <NUM> to direct the transport drive system <NUM> to provide appropriate driving force to the left and/or right wheels <NUM>.

<FIG> illustrates the mobile radiography system <NUM> in a fully docked configuration used for transporting the mobile radiography system <NUM> to an intended location within a medical care facility. The fully docked configuration may be defined as having the base section <NUM> rotated such that the boom <NUM> extends over the top surface <NUM> of the base frame <NUM>, the extendable section <NUM> lowered along axis V until boom <NUM> is proximate to the top surface <NUM>, and the boom <NUM> is fully telescopically collapsed to shorten it. For ease of operation under varying conditions, an operator should be able to easily manually position and orient the x-ray source <NUM> for imaging or for transport without the need of additional tools and without needing help from additional personnel. This includes moving the x-ray source <NUM> from an undocked imaging configuration (<FIG>) to a docked configuration (<FIG>) and vice versa. The mechanics of providing ease of positioning is complicated by the weight of the x-ray source <NUM> and by its extension outward along axis H from the vertical axis V. The docked transport position helps to protect the x-ray source <NUM> from damage or from causing an obstruction during movement of the mobile radiography system <NUM>. It also places the boom <NUM> and x-ray source <NUM> over a center of gravity of the mobile radiography system <NUM> to increase stability. In particular, when the mobile radiography system <NUM> is wheeled onto a sloped, inclined, or otherwise uneven, surface, the possibility of the system <NUM> tipping may be minimized by disabling, locking, deactivating or preventing portions of the mobile radiography system <NUM> from being activated, deployed or moved.

In accordance with the present invention, a mobile radiography system as set forth in claim <NUM> is provided. Preferred embodiments of the invention are claimed in the dependent claims.

In one embodiment, a mobile digital radiography system has a wheeled base with a transport drive system for driving the wheels. An x-ray head is attached to the wheeled base using an adjustable support arm. An electronic control system receives operator input to selectively operate the radiography system. A detector senses either one or both of a tilt angle and a pitch angle of the mobile radiography system. A stored control program executable by the electronic control system receives one or both of the tilt angle and the pitch angle sensed by the detector and then automatically disables, locks or deactivates the transport drive system or the support arm or both if the received tilt angle or pitch angle exceeds a pre-set threshold.

In one embodiment, a method of operating a mobile radiography system having a base with wheels is disclosed. A step of sensing a tilt or pitch angle of the wheeled base of the mobile radiography system is performed and, if the sensed tilt or pitch angle exceeds a pre-set threshold, the wheels of the base are prevented from turning, such as by locking the wheels or deactivating a drive system.

This brief description of the invention is intended only to provide a brief overview of subject matter disclosed herein according to one or more illustrative embodiments, and does not serve as a guide to interpreting the claims or to define or limit the scope of the invention, which is defined only by the appended claims. This brief description is provided to introduce an illustrative selection of concepts in a simplified form that are further described below in the detailed description. This brief description is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.

A detailed description of the invention may be had by reference to certain embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the drawings illustrate only certain embodiments of this invention and are therefore not to be considered limiting of its scope, for the scope of the invention encompasses other equally effective embodiments. The drawings are not necessarily to scale, emphasis generally being placed upon illustrating the features of certain embodiments of the invention. In the drawings, like numerals are used to indicate like parts throughout the various views. Thus, for further understanding of the invention, reference can be made to the following detailed description, read in connection with the drawings in which:.

<FIG> further illustrates additional features useful for enabling embodiments of the present invention. An inclination detection device <NUM>, such as an accelerometer, is provided in the base frame <NUM> to detect an inclination angle of the mobile radiography system <NUM>. The accelerometer may include a two-dimensional or three-dimensional accelerometer to detect an inclination deviation of the mobile radiography system <NUM> from a level horizontal front-to-back dimension x and from a level horizontal side-to-side dimension y, which is perpendicular to the x dimension in the horizontal plane, and to report angular deviation measurement data to the processing system <NUM>, as detected.

A boom lock <NUM> in electrical communication with processing system <NUM> may be configured to prevent telescopic extension of the boom <NUM> when the boom lock is activated. The boom lock <NUM>, such as a solenoid lock, may be electronically controlled by the processing system <NUM> via a signal transmitted to the boom lock <NUM> to engage collapsed portions of the telescopic boom <NUM>, such as by positioning a plunger through aligned holes in the telescopic sections, thereby preventing the boom <NUM> from being telescopically extended.

Similarly, a wheel lock <NUM> in electrical communication with processing system <NUM> may be configured to be electronically controlled by the processing system <NUM> via a signal transmitted to the wheel lock <NUM> to forcibly engage the wheel brakes, thereby preventing the wheels <NUM> from rotating. If the mobile radiography system <NUM> does not include motor driven wheels, rather, wheels having free play, then the wheel lock <NUM>, such as a solenoid lock, may be electronically controlled by the processing system <NUM> via a signal transmitted to the wheel lock <NUM> to engage a rim of the wheel <NUM>, such as by positioning a plunger through an opening in the rim, thereby preventing the wheel <NUM> from rotating. In one embodiment, if using a motorized transport system <NUM>, the central processing system <NUM> may be programmed to power down the transport drive system <NUM> to prevent the wheels <NUM> from rotating.

Similarly, a column lock <NUM> in electrical communication with processing system <NUM> may be configured to be electronically controlled by the processing system <NUM> via a signal transmitted to the column lock <NUM> to engage the base section <NUM> and the extendable section <NUM>, such as by positioning a plunger through aligned holes in the base section <NUM> and the extendable section <NUM>, thereby preventing the base section <NUM> and the extendable section <NUM> from rotating relative to the base frame <NUM>, and preventing the extendable section <NUM> from being raised or lowered.

<FIG> is a flow chart that may be embodied in a computer program executable by the mobile radiography system <NUM> using the electronic control system or processing system <NUM> housed in the mobile radiography system <NUM> to control mobility and boom <NUM> deployment based on whether an angle of inclination of the mobile radiography system <NUM> is greater than a pre-set threshold, such as a three (<NUM>) degree offset from a level horizontal orientation. At step <NUM>, the detector <NUM> detects whether the mobile radiography system is positioned on an incline, such as on an inclined, or tilted, floor, by determining an angle of inclination and transmitting the detected angle data to central processing system <NUM>, which compares the received angle data to a pre-set threshold, such as the three (<NUM>) degree threshold deviation from a level horizontal orientation. Other numerical pre-sets may be selected by an operator and stored in the processing system <NUM> as a deviation threshold instead of three (<NUM>) degrees. In the example operations described herein, an exemplary preset of three (<NUM>) degrees will be used.

In one embodiment, an angle of inclination may be determined by detector <NUM> in the two horizontal perpendicular dimensions x and y. For example, an accelerometer <NUM> may be disposed within the mobile radiography system <NUM> to determine a tilt angle excursion along a front-to-back axis x of the mobile radiography system <NUM>, or a pitch angle excursion along a side-to-side axis y of the mobile radiography system <NUM>, or both. At step <NUM>, if the detector <NUM> does not detect an excursion beyond the pre-set tilt angle or pitch angle threshold then it transmits a signal ("N") to the control or processing system <NUM> indicating that the mobile radiography system <NUM> is on a satisfactory level surface.

At an optional step <NUM>, the mobile radiography system may determine whether the support arm is docked or undocked using the signals from base sensor <NUM> and column sensor <NUM> and, if undocked, the central processing system may restrict a driving speed of mobile radiography system <NUM> at step <NUM>, such as by electronically limiting the transport drive system <NUM> to half speed, or some other lowered top speed. Without the optional step <NUM>, then after determining that the mobile radiography system <NUM> is not on an incline at step <NUM>, processing system <NUM> may allow mobile radiography system <NUM> to be driven in the normal course at step <NUM> and, if mobile radiography system <NUM> is not in motion by being driven, the support arm may be allowed to be undocked at step <NUM> by not activating the column lock <NUM> and the boom lock <NUM>. At step <NUM>, if the detector <NUM> senses an excursion beyond the pre-set three degree threshold in either of the xy (tilt, pitch) dimensions then it transmits a deviation signal ("Y") to the control or processing system <NUM>. At step <NUM>, if the boom is determined to be undocked ("N"), the mobile radiography system <NUM> will be prevented from being driven at step <NUM>, such as by disabling the transport drive system <NUM>, forcibly applying a brake to the wheels or locking the wheels <NUM> by activating the wheel lock <NUM>, as described herein. In this situation, the mobile radiography system <NUM> may be rolled or driven whenever the support arm is returned to a docked position. At step <NUM>, if the boom <NUM> is determined to be docked ("Y") then the mobile radiography system <NUM> will be prevent the boom <NUM> from being undocked at step <NUM> such as by activating the column lock <NUM> and/or the boom lock <NUM>, and the mobile radiography system <NUM> may be driven or rolled. In the latter situation, the mobile radiography system may be undocked whenever the system is eventually driven or rolled onto a surface whose slope is detected to not exceed three (<NUM>) degrees. The flow chart of <FIG> may be repeated at variously programmable cycle times, ranging from several times per second to once every several seconds. A shorter cycle time enables the mobile radiography system <NUM> to respond quickly to changes in status as illustrated in <FIG>.

To prevent, disable, or deactivate the transport drive system <NUM> from driving or rolling the mobile radiography system, the processing system <NUM> may be electrically coupled to an electronic motor control of the transport drive system <NUM> configured to be disabled by a signal from the processing system <NUM>. In one embodiment wherein the wheels <NUM> are in free play, the processing system <NUM> may be coupled to an electronically activatable brake or to the wheel lock <NUM> attached to one or more wheels, whereby the one or more wheels may be prevented from turning. Similarly, to prevent the boom <NUM> from being extended, a signal from the processing system <NUM> may be used to activate a boom lock <NUM>. To prevent the extendable column section <NUM> from being moved, a signal from the processing system <NUM> may be used to activate the column lock <NUM>. To prevent the rotation of the base section <NUM> and the extendable column section <NUM> relative to the base frame <NUM>, a signal from the processing system <NUM> may be used to activate the column lock <NUM>. After each of the steps <NUM>, <NUM>, <NUM> and <NUM>, the flow chart returns to step <NUM> to repeat the step of checking inclination of the mobile radiography system <NUM> as described herein above. The method of the flow chart of <FIG> may be performed while the mobile radiography system <NUM> is powered on and being operated, such as being driven over a surface, and while it is standing still.

<FIG> is a flow chart that may be embodied in a computer program executable by the mobile radiography system <NUM> using the electronic control system or processing system <NUM> housed in the mobile radiography system <NUM> to determine whether an angle of inclination of the mobile radiography system <NUM> is greater than a pre-set threshold, such as a three (<NUM>) degree offset from a level horizontal orientation, which then provides a Y (yes) or N (no) output to step <NUM> of the flow chart of <FIG>. At step <NUM>, the inclination detector <NUM>, such as an accelerometer, monitors, detects and reports to the processing system <NUM> at least xy tilt/pitch data in two detected dimensions. At step <NUM> the processing system <NUM> receives the accelerometer data from the detector <NUM>. At step <NUM> the tilt x angle data is selected and, at step <NUM>, the tilt angle x data is compared to a pre-set tilt threshold to determine if the tilt angle exceeds the tilt threshold. If the tilt angle does not equal or exceed the pre-set tilt threshold then, at step <NUM>, a tilt flag is set to (FALSE). If the tilt angle equals or exceeds the pre-set tilt threshold then, at step <NUM>, the tilt flag is set to (TRUE).

Returning to step <NUM>, after the the processing system <NUM> receives the accelerometer data from the detector <NUM>, the processing system <NUM> also selects the pitch y angle data at step <NUM> and, at step <NUM>, the pitch angle y data is compared to a pre-set pitch threshold to determine if the pitch angle exceeds the pitch threshold. If the pitch angle equals or exceeds the pre-set pitch threshold then, at step <NUM>, a pitch flag is set to (TRUE). If the pitch angle does not equal or exceed the pre-set pitch threshold then, at step <NUM>, a pitch flag is set to (FALSE). If either a tilt flag or a pitch flag is set to TRUE then, at step <NUM>, the cart ramp status is set to Y (yes). If both the tilt flag and the pitch flag is set to FALSE then, at step <NUM>, the cart ramp status is set to N (no). At step <NUM>, the determined cart ramp status is sent to step <NUM> of the flow chart of <FIG>.

As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method, or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.), or an embodiment combining software and hardware aspects that may all generally be referred to herein as a "service," "circuit," "circuitry," "module," and/or "system.

Program code and/or executable instructions embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the mobile radiography system's processing system <NUM>, partly on the processing system <NUM>, as a stand-alone software package, partly on the processing system <NUM> and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the mobile radiography system <NUM> through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention.

The computer program instructions may also be loaded onto a computer, other programmable data processing system, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable system provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

Claim 1:
A mobile radiography system (<NUM>) comprising:
a base (<NUM>) including wheels (<NUM>) and a transport drive system (<NUM>) configured to drive the wheels to transport the mobile radiography system (<NUM>);
a movable support arm (<NUM>, <NUM>, <NUM>) attached to the wheeled base (<NUM>);
an x-ray assembly (<NUM>) attached to the movable support arm (<NUM>, <NUM>, <NUM>);
an electronic control system (<NUM>) configured to receive operator input to selectively operate the transport drive system (<NUM>);
a detector (<NUM>) configured to sense either one or both of a tilt angle and a pitch angle of the mobile radiography system (<NUM>); and
a stored control program executable by the electronic control system (<NUM>) to receive one or both of the tilt angle and the pitch angle sensed by the detector (<NUM>), the stored control program configured to automatically disable at least a portion of the transport drive system (<NUM>) or at least a portion of the movable support arm (<NUM>, <NUM>, <NUM>) or both if the received tilt angle or pitch angle exceeds a pre-set threshold;
wherein said at least a portion of the transport drive system (<NUM>) is automatically disabled if the movable support arm (<NUM>, <NUM>, <NUM>) is undocked when the received tilt angle or pitch angle exceeds the pre-set threshold,
wherein said at least a portion of the transport drive system (<NUM>) is not automatically disabled if the movable support arm (<NUM>, <NUM>, <NUM>) is docked and said at least a portion of the movable support arm (<NUM>, <NUM>, <NUM>) is locked in the docked position, when the received tilt angle or pitch angle exceeds the pre-set threshold.