Patent Description:
Document <CIT> discloses 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 a 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.

A multi-axis imaging system according to the present invention is defined in claim <NUM>. Optional features are defined in the dependent claims.

Exemplary embodiments include a multi-axis imaging system and methods for imaging a human or animal using a multi-axis imaging system.

The various exemplary embodiments include a multi-axis imaging system that includes an imaging gantry, a support column that supports the imaging gantry on one side of the gantry in a cantilevered manner, a base that supports the imaging gantry and the support column, a first drive mechanism that translates the gantry in a vertical direction relative to the support column, a second drive mechanism that rotates the gantry with respect to the support column, and a third drive mechanism that translates the support column and the gantry in a horizontal direction relative to the base.

Further exemplary embodiments include a method of operating a multi-axis imaging system comprising a moveable imaging gantry, the method including receiving, from a control system of a moveable patient support, data indicating the configuration of the patient support, and sending control signals to one or more drive systems of the multi-axis imaging system to cause the gantry to translate and/or rotate to maintain the gantry spaced away from the patient support and a bore of the gantry aligned with the patient support in response to the data received from the control system of the moveable patient support.

Further exemplary embodiments include a control system for a multi-axis imaging system having a moveable imaging gantry and a movable patient support, the control system including a memory and a processor configured with processor-executable instructions to perform operations including receiving data indicating a configuration of the movable patient support, and sending control signals to one or more drive systems of the multi-axis imaging system to cause the gantry to translate and/or rotate to maintain the gantry spaced away from the patient support and a bore of the gantry aligned with the patient support in response to the data received from the control system of the moveable patient support.

Further exemplary embodiments include a multi-axis imaging system for imaging an animal in a weight-bearing position that includes a gantry, a support column that supports the gantry, and a support stage on which an animal stands, wherein the gantry is translatable with respect to the support stage in a vertical direction to scan one or more legs of the animal standing on the support stage and the gantry is translatable in a vertical and in a horizontal direction with respect to the support stage to scan a head and/or neck of the animal standing on the support stage.

Other features and advantages of the present invention will be apparent from the following detailed description of the invention, taken in conjunction with the accompanying drawings of which:.

This application is related to<CIT>, and to <CIT>.

Referring to <FIG>, an imaging system <NUM> according to one embodiment of the invention is shown. The system <NUM> includes image collection components, such as a rotating x-ray source and detector array, a rotating gamma-ray camera or stationary magnetic resonance imaging components, that are housed within the gantry <NUM>. The system <NUM> is configured to collect imaging data, such as, for example x-ray computed tomography (CT), positron emission tomography (PET), single-photon emission computed tomography (SPECT) or magnetic resonance imaging (MRI) data, from an object located within the bore <NUM> of the gantry <NUM>, in any manner known in the medical imaging field. In embodiments, the system <NUM> may be an x-ray CT imaging system, and may include an x-ray source and a detector located within the gantry <NUM>. The gantry <NUM> may also include other components, such as a high-voltage generator, a heat exchanger, a power supply (e.g., battery system), and a computer. These components may be mounted on a rotating element (e.g., a rotor) that rotates within the gantry <NUM> during an imaging scan. A rotor drive mechanism may also be located on the rotor, and may drive the rotation of the rotor. Between scans, a docking system may be used to couple the rotating and non-rotating portions of the system <NUM> for power and data communication.

The gantry <NUM> may be mounted to a support column <NUM>. The support column <NUM> may be attached to the gantry <NUM> on a first side of the gantry <NUM> and may support the gantry <NUM> in a cantilevered manner. The gantry <NUM> may be a generally O-shaped structure having a central imaging bore <NUM> and defining an imaging axis <NUM> extending through the bore. The system <NUM> may also include a base <NUM> that may be located on a weight-bearing surface, such as a floor <NUM> of a building. In the illustrated embodiment, the base <NUM> comprises a generally rectilinear support structure that may be mounted (e.g., bolted) to the floor <NUM>. The support column <NUM> may be located on and supported by the base <NUM> and may extend upwards from the top surface of the base <NUM> in a generally vertical direction. The support column <NUM> may have a length dimension that extends vertically at least about <NUM> meters, such as <NUM>-<NUM> meters (e.g., about <NUM> meters).

In various embodiments discussed in further detail below, the system <NUM> may enable imaging (e.g., CT scanning) in multiple orientations and along multiple directions. In embodiments, the system <NUM> may include a first drive mechanism for translating the gantry <NUM> relative to the support column <NUM> in a first direction along the direction of arrow <NUM> in <FIG>. The first direction <NUM> may be a generally vertical direction (i.e., perpendicular to the floor <NUM>), which for the purposes of this disclosure may be defined as ±<NUM>° from true vertical. The system <NUM> may also include a second drive mechanism for rotating the gantry <NUM> relative to the support column <NUM> in the direction indicated by arrow <NUM>. The rotation of the gantry <NUM> may be with respect to an axis <NUM> that extends orthogonal to the first direction <NUM> and may be generally parallel to the floor <NUM>. The axis <NUM> may extend through the isocenter of the bore <NUM> of the gantry <NUM>. The system may also include a third drive mechanism for translating the gantry <NUM> and support column <NUM> with respect to the base <NUM> in a second direction indicated by arrow <NUM> in <FIG>. The second direction <NUM> may be a generally horizontal direction (i.e., parallel to the floor <NUM>), which for the purposes of this disclosure may be defined as ±<NUM>° from true horizontal. The second direction <NUM> may be orthogonal to both the first direction <NUM> and to the rotation axis <NUM>.

<FIG>, <FIG> and <FIG> illustrate an imaging system <NUM> in various configurations for performing imaging scans along multiple axes. In <FIG>, the support column <NUM> may support the gantry <NUM> in a generally vertical orientation, such that the front and rear faces of the gantry <NUM> extend parallel to the floor <NUM> and the imaging axis <NUM> through the gantry bore <NUM> extends in a vertical direction (i.e., perpendicular to the floor). The imaging axis <NUM> of the gantry <NUM> in this configuration may extend parallel to the length dimension of the vertically-extending support column <NUM>.

The gantry <NUM> may be displaced along the length of the support column <NUM> in a generally vertical direction. This is illustrated in <FIG>, which show the gantry <NUM> displaced vertically from a first position in <FIG> with the gantry <NUM> located proximate a first end of the support column <NUM> (i.e., opposite the base <NUM>), to a second position in <FIG> with the gantry <NUM> located approximately midway along the length of the support column <NUM>, to a third position in <FIG>, with the gantry <NUM> located proximate to a second end of the support column <NUM> proximate to the base <NUM>. The gantry <NUM> and the support column <NUM> may include mating features that confine the displacement of the gantry <NUM> along the length of the support column <NUM>. As shown in <FIG>, for example, a pair of parallel rails <NUM>, <NUM> may extend in a vertical direction along the length of the support column <NUM>. A carriage <NUM> may be mounted to the side of the gantry <NUM> that attaches to the support column <NUM>. The carriage <NUM> may include bearing elements (e.g., roller and/or dovetail bearing slides) that engage with the rails <NUM>, <NUM> to provide linear motion of the carriage <NUM> and gantry <NUM> along the length of the support column <NUM>.

A first drive mechanism may drive the displacement of the gantry <NUM> relative to the support column <NUM>. An example of the first drive system <NUM> is described below with reference to <FIG>. A controller <NUM> (see <FIG>) may control the operation of the first drive mechanism <NUM> and thereby control the vertical displacement of the gantry <NUM>. The controller may receive position feedback signals indicative of the position of the gantry <NUM> along the support column <NUM>, such as from a linear encoder.

The system <NUM> may also include a patient support <NUM>. The patient support <NUM> may support a patient <NUM> in a weight-bearing standing position as shown in <FIG>. The patient support <NUM> may include a first portion <NUM> that supports the feet of a patient upon which the patient <NUM> may stand. A second portion <NUM> may extend generally perpendicular to the first portion <NUM> and may provide additional support to the patient <NUM>. For example, the patient <NUM> may lean against the second portion <NUM> during a scan and the second portion <NUM> may help to stabilize the patient <NUM> and prevent the patient <NUM> from falling off the patient support <NUM>. In embodiments, the patient support <NUM> may support the patient <NUM> in a position that is raised above the floor <NUM>, as shown in <FIG>. The first portion <NUM> and the second portion <NUM> may be made of a radiolucent (x-ray transparent) material, such as carbon fiber material.

The system <NUM> may be used to perform an imaging scan of a patient <NUM> in a weight-bearing standing position. For example, for an x-ray CT imaging system, the x-ray source and detector may rotate within the gantry <NUM> around the patient while the gantry <NUM> is displaced vertically on the support column <NUM> as shown in <FIG> to perform a helical scan of a patient <NUM> positioned on the patient support <NUM>. In embodiments, the system <NUM> may scan over the full length of the patient (e.g., from the top of the patient's cranium to the bottom of the patient's feet) or any selected portion thereof. Following a scan, the gantry <NUM> may be moved to an out-of-the way position (e.g., to the top of the support column <NUM> or below the patient's feet) and the patient <NUM> may be removed from the patient support <NUM>.

The gantry <NUM> may be attached to the support column <NUM> such that the gantry <NUM> may rotate (i.e., tilt) with respect to the support column <NUM>. This is illustrated in <FIG>, which illustrate the gantry <NUM> tilted from a generally vertical orientation (as shown in <FIG>) with the front and rear faces of the gantry <NUM> extending parallel to the floor <NUM> and the imaging axis <NUM> extending in a vertical direction (i.e., perpendicular to the floor) to a generally horizontal orientation with the front and rear faces of the gantry extending perpendicular to the floor <NUM> and the imaging axis <NUM> extending in a horizontal direction (i.e., parallel to the floor). The imaging axis <NUM> of the gantry <NUM> in the configuration shown in <FIG> may extend perpendicular to the length dimension of the vertically-extending support column <NUM>.

In embodiments, a rotary bearing may enable the rotation of the gantry <NUM> with respect to the support column <NUM>. In one embodiment, the rotary bearing may include a first portion (i.e., bearing race) mounted to the carriage <NUM> and a second portion (i.e., bearing race) mounted to the gantry <NUM>. The two bearing portions may rotate concentrically relative to one another such that the gantry <NUM> may be rotated relative to the carriage <NUM> and support column <NUM>. In embodiments, the gantry <NUM> may rotate at least about <NUM>° relative to the support column <NUM> (e.g., as is illustrated by <FIG> and <FIG>). In some embodiments, the gantry <NUM> may rotate at least about <NUM>°, such as at least about <NUM>°, including about <NUM>° or more, relative to the support column <NUM>.

A second drive mechanism may drive the rotation of the gantry <NUM> relative to the support column <NUM>. An example of the second drive system <NUM> is described below with reference to <FIG>. The system controller <NUM> (see <FIG>) may control the operation of the second drive mechanism <NUM> and thereby control the rotational angle (tilt) of the gantry <NUM> relative to the support column <NUM>. The controller may receive position feedback signals indicative of the rotational position of the gantry <NUM> with respect to the support column <NUM>, such as from a rotary encoder.

In some embodiments, the patient support <NUM> may move from a first configuration as shown in <FIG> to a second configuration as shown in <FIG>. In the configuration of <FIG>, the first portion <NUM> of the patient support <NUM> may extend in a generally horizontal direction (i.e., parallel to the floor <NUM>) and the second portion <NUM> may extend in a generally vertical direction (i.e., away from the floor <NUM>). In the configuration of <FIG>, the second portion <NUM> of the patient support <NUM> may extend in a generally horizontal direction (i.e., parallel to the floor <NUM>) and the first portion <NUM> may extend in a generally vertical direction. Put another way, the patient support <NUM> may tilt by a predetermined angle (e.g., ~<NUM>°) relative to the floor <NUM> between the configuration shown in <FIG> and the configuration shown in <FIG>. In embodiments, the table configuration of <FIG> may be used for scanning a patient in a weight-bearing standing position and the table configuration of <FIG> may be used for scanning a patient in a lying position, as in conventional x-ray CT systems.

In some embodiments, the patient support <NUM> may rotate (tilt) with respect to a linkage member <NUM> to which the patient support <NUM> is attached. In embodiments, the linkage member <NUM> may also rotate with respect to the floor <NUM>. For example, the linkage member <NUM> may be attached to a base <NUM> that may be mounted to the floor <NUM>. The linkage member <NUM> may rotate relative to the base <NUM>. The rotation of the linkage member <NUM> relative to the base <NUM> may raise and lower the patient support <NUM> relative to the floor <NUM>. A table control system may provide coordinated rotational motion of the patient support <NUM> relative to the linkage member <NUM> and rotational motion of the linkage member <NUM> relative to the base <NUM> to move the table system from the configuration shown in <FIG> to the configuration shown in <FIG>. An example of a patient table system that may be used with the system <NUM> is described in <CIT>.

<FIG> illustrate the system <NUM> performing an imaging scan of a patient <NUM> in a lying position. In particular, for an x-ray CT imaging system, the x-ray source and detector may rotate within the gantry <NUM> around the patient <NUM> while the gantry <NUM> is translated relative to the patient support <NUM> in a generally horizontal direction to perform a helical scan of a patient <NUM> lying on the patient support <NUM>. In the embodiment shown in <FIG>, the gantry <NUM> and the support column <NUM> may translate relative to the patient <NUM> and patient support <NUM>, which may be stationary during the scan. The gantry <NUM> and the support column <NUM> may translate along the length of the base <NUM>. As shown in <FIG>, the gantry <NUM> may be displaced vertically on the support column <NUM> such that the patient <NUM> is aligned with the bore <NUM> of the gantry <NUM> and the imaging axis <NUM> extends along the length of the patient <NUM>. The gantry <NUM> and the support column <NUM> may then translate along the base <NUM> in a horizontal direction from a first position as shown in <FIG> with the gantry <NUM> located over the head of the patient <NUM>, to a second position as shown in <FIG> with the gantry <NUM> located over the mid-section of the patient <NUM>, to a third position as shown in <FIG> with the gantry <NUM> located over the feet of the patient <NUM>. The system <NUM> may perform a horizontal scan over the full length of the patient <NUM> or any selected portion thereof.

The base <NUM> and the support column <NUM> may include mating features that confine the translation of the support column in a horizontal direction along the length of the base <NUM>. In the example of <FIG>, the base <NUM> may include rails or tracks that may mate with corresponding features at the bottom of the support column <NUM> to guide the translation of the support column <NUM> in a horizontal direction. A third drive mechanism may drive the translation of the support column <NUM> relative to the base <NUM>. An example of a third drive mechanism <NUM> for translating the gantry <NUM> and support column <NUM> is schematically illustrated in <FIG>. The third drive mechanism <NUM> may comprise, for example, a belt drive, a drive wheel, a lead screw, a ball screw, a pulley, etc. or various combinations therefore. The third drive mechanism <NUM> may be mechanically coupled to and driven by one or more motors, which may be located in the support column <NUM> and/or the base <NUM>. The system controller <NUM> (see <FIG>) may control the operation of the third drive mechanism <NUM> and thereby control the horizontal translation of the support column <NUM> and gantry <NUM>. The controller <NUM> may receive position feedback signals indicative of the position of the support column <NUM> relative to the base <NUM>, such as from a linear encoder.

<FIG> illustrate the system <NUM> performing an imaging scan of a patient <NUM> along a tilted axis. The patient <NUM> may be supported by the patient support <NUM> at an oblique angle such that an axis <NUM> extending lengthwise through the patient <NUM> is neither parallel or perpendicular to the floor <NUM>. This may be achieved, for example, by rotating (tilting) the patient support <NUM> and patient <NUM> from a standing position (as shown in <FIG>) or rotating (tilting) the patient support <NUM> and patient <NUM> upwards from a lying position (as shown in <FIG>). The controller <NUM> may control the second drive mechanism <NUM> to rotate (tilt) the gantry <NUM> with respect to the support column <NUM> such that the imaging axis <NUM> through the bore <NUM> is parallel to, and optionally collinear with, the patient axis <NUM>. The system <NUM> may perform an imaging scan (e.g., a helical x-ray CT scan) of the patient <NUM> by moving the gantry <NUM> in the direction of the tilted patient axis <NUM> while maintaining a fixed angle between the gantry <NUM> and axis <NUM>. In various embodiments, the controller <NUM> of the imaging system <NUM> may provide a coordinated movement of the gantry <NUM> relative to the support column <NUM> in a vertical direction with a movement of the gantry <NUM> and support column <NUM> relative to the base <NUM> in a horizontal direction. The controller <NUM> may include logic configured to determine the relative vertical and horizontal displacement of the gantry <NUM> needed to move the gantry <NUM> along the tilted axis <NUM>. The controller <NUM> may send control signals to the first drive mechanism <NUM> and to the third drive mechanism <NUM> to provide coordinated vertical and horizontal displacement of the gantry <NUM>. Where the angle of the tilted axis <NUM> is known or may be determined, the controller <NUM> may use simple trigonometric relations to determine the vertical and horizontal displacement of the gantry <NUM>. As in the embodiment of <FIG>, for example, where the tilted axis <NUM> is at an angle of <NUM>° relative to horizontal, each cm of the scan along the axis <NUM> may include a vertical displacement of the gantry <NUM> relative to the support column <NUM> of ~<NUM> (i.e., sin <NUM>°) and a horizontal displacement of the gantry <NUM> and support column <NUM> relative to the base <NUM> of <NUM> (i.e., cos <NUM>°). Thus, the imaging system <NUM> may perform a scan at any tilt axis <NUM>, and in embodiments may perform scans along complex axes, such as along a multi-angled or curved axis.

<FIG> illustrate the system <NUM> performing an imaging scan of a patient <NUM> along a tilted axis <NUM>. In particular, for an x-ray CT imaging system, the x-ray source and detector may rotate within the gantry <NUM> around the patient <NUM> while the gantry <NUM> is displaced in both vertical and horizontal directions to perform a helical scan of the patient <NUM> along a tilted axis <NUM>. The patient may be supported on a patient support <NUM> that may be tilted such that the second portion <NUM> of the patient support <NUM> may extend parallel to the tilted axis <NUM>. The gantry <NUM> may be tilted on the support column <NUM> to align the gantry imaging axis <NUM> with the tilted axis <NUM>. The gantry <NUM> may be moved in both a vertical and horizontal direction from a first position as shown in <FIG> with the located over the head of the patient <NUM>, to a second position as shown in <FIG> with the gantry <NUM> located over the mid-section of the patient <NUM>, to a third position as shown in <FIG> with the gantry <NUM> located over the feet of the patient <NUM>. The system <NUM> may perform scan over the full length of the patient <NUM> or any selected portion thereof.

<FIG> illustrate an example of a support column <NUM> for a multi-axis imaging system. <FIG> is a front perspective view of a support column <NUM>. <FIG> is a rear, partially-transparent perspective view of the support column <NUM> showing an interior portion thereof. <FIG> is a cross-section view taken lengthwise through the support column <NUM>. <FIG> illustrates the first and second drive mechanisms <NUM>, <NUM> with the surrounding support structure of the support column <NUM> removed.

The support column <NUM> may be formed of a high-strength structural material, such as aluminum. The support column <NUM> may include a hollow interior that may form one or more interior housings or compartments. In the embodiment of <FIG>, the support column <NUM> may include a first interior housing <NUM> that extends lengthwise in a front portion of the support column <NUM>, and at least one second interior housing <NUM> in a rear portion of the support column. As shown in <FIG>, for example, a front cover <NUM> may cover the first interior housing <NUM>, and an elongated opening or slot <NUM> may provide access to the first interior housing <NUM>. The parallel rails <NUM>, <NUM> which are engaged by the bearing elements <NUM>, <NUM> of the carriage <NUM> may be attached to the front face of the support column <NUM>. In some embodiments, the beds on which the rails <NUM>, <NUM> are mounted may be counter-machined to offset any deflection of the support column <NUM> that may result from the load of the cantilevered gantry <NUM> as it travels up and down the column <NUM>.

The first drive mechanism <NUM> for driving the vertical translation of the gantry <NUM> may be located on the support column <NUM>. The first drive mechanism <NUM> may comprise a linear actuator, such as a lead screw or ball screw system. As shown in <FIG> and <FIG>, a threaded shaft <NUM> may extend lengthwise within the first interior housing <NUM> of the support column <NUM>. A motor <NUM>, which may be located in the second interior housing <NUM> of the support column <NUM>, may be geared into the threaded shaft <NUM> to drive the rotation of the shaft <NUM>. In one embodiment, the motor <NUM> may drive a toothed belt <NUM> that may engage with a sprocket wheel <NUM> to drive the rotation of the threaded shaft <NUM>. An arm <NUM> may extend from the carriage <NUM> into the first interior housing <NUM> (e.g., through the opening <NUM> shown in <FIG>). A nut <NUM> on the end of the arm <NUM> may engage with the threaded shaft <NUM>. The rotation of the threaded shaft <NUM> may cause the nut <NUM> to reciprocate up and down along the length of the shaft <NUM>. The reciprocation of the nut <NUM> on the shaft <NUM> may drive the vertical displacement of the carriage <NUM> and gantry <NUM> with respect to the support column <NUM>. A controller <NUM> (see <FIG>) may control the operation of the first drive mechanism <NUM> and thereby control the vertical displacement of the gantry <NUM>. The controller may receive position feedback signals indicative of the position of the gantry <NUM> along the support column <NUM>, such as from a linear encoder.

The first drive mechanism <NUM> may be non-backdrivable under normal and/or rated operating loads (which could be, for example, up to about <NUM> lbs. This may provide improved safety of the system <NUM>. In embodiments, the first drive mechanism <NUM> may include a non-backdrivable lead screw. Alternately, the first drive mechanism <NUM> may be a backdrivable actuator, such as a ball screw. An additional safety mechanism, such as a spring-set brake, may be utilized to prevent backdriving under load.

The second drive mechanism <NUM> for driving the rotation <NUM> of the gantry <NUM> relative to the support column <NUM> may be located on the carriage <NUM>. In the embodiment of <FIG>, a motor <NUM> may be attached to one side of the carriage <NUM>. The motor <NUM> may be geared into a sprocket wheel <NUM> that is adjacent to the outer race <NUM> of a rotary bearing <NUM>. The outer race <NUM> of the bearing <NUM> may be attached to the gantry <NUM> and the inner race <NUM> of the bearing <NUM> may be attached to the carriage <NUM>. A toothed belt <NUM> may extend over at least a portion of the outer circumference of the outer race <NUM> and may engage with a toothed surface of the outer race <NUM>. The belt <NUM> may be looped over the sprocket wheel <NUM> that is driven by the motor <NUM> such that the rotation of the sprocket wheel <NUM> in a clockwise or counterclockwise direction causes a corresponding rotation of the outer race <NUM> and gantry <NUM> relative to the inner race <NUM>, carriage <NUM> and support column <NUM>. The second drive mechanism <NUM> preferably includes minimal lash between the belt <NUM>, sprocket wheel <NUM> and toothed surface of the outer race <NUM> to enable precise rotational control of the gantry <NUM>. In embodiments, the belt <NUM> may not be continuous, and opposing ends of the belt <NUM> may be bolted or clamped to the outer race <NUM> to minimize slippage and/or backlash. In embodiments, the belt <NUM> may be clamped to enable at least about <NUM>°, including about <NUM>° or more, of rotation of the gantry <NUM> relative to the support column <NUM>. In some embodiments, a brake system may be selectively engaged to hold the rotational (tilt) position of the gantry <NUM> (e.g., during a scan). The controller <NUM> (see <FIG>) may control the operation of the second drive mechanism <NUM> and thereby control the rotational displacement of the gantry <NUM>. The controller may receive position feedback signals indicative of the rotational position of the gantry <NUM> with respect the support column <NUM>, such as from a rotary encoder.

<FIG> illustrate a base <NUM> of a multi-axis imaging system <NUM> according to an embodiment. The base <NUM> may include a generally rectangular support frame <NUM>. A pair of parallel support rails <NUM>, <NUM> may extend lengthwise along the base <NUM>. The support rails <NUM>, <NUM> may support the support column <NUM> and inhibit deflection as the support column <NUM> traverses along the length of the base <NUM>. A pair of guide rails <NUM>, <NUM> may extend along a bottom surface of the base <NUM> and may be parallel to the support rails <NUM>, <NUM>. A platform <NUM> may be located over the support rails <NUM>, <NUM>. The support column <NUM> may be attached (e.g., screwed or bolted) to the upper surface of the platform <NUM>. The platform <NUM> may include bearing elements <NUM> (e.g., bearing slides) that engage with the guide rails <NUM>, <NUM> to provide linear motion of the platform <NUM>, support column <NUM> and gantry <NUM> along the length of the base <NUM>.

The third drive mechanism <NUM> for driving the horizontal translation of the gantry <NUM> and support column <NUM> may be located on the base <NUM>. The third drive mechanism <NUM> may comprise a motor <NUM> that may be attached to the platform <NUM>. The motor <NUM> may be geared into a sprocket wheel <NUM>. A drive belt <NUM> may extend lengthwise along the bottom surface of the base <NUM>. A portion of the drive belt <NUM> adjacent to the platform <NUM> may be looped over and engage with the sprocket wheel <NUM> that is driven by the motor <NUM>. The driving of the sprocket wheel <NUM> by the motor <NUM> may cause the sprocket wheel <NUM> and platform <NUM> to traverse up and down the length of the drive belt <NUM>, thereby driving the translation of the platform <NUM>, support column <NUM> and gantry <NUM> along the length of the base <NUM>. The controller <NUM> (see <FIG>) may control the operation of the third drive mechanism <NUM> and thereby control the translation of the gantry <NUM> and support column <NUM> relative to the base. The controller <NUM> may receive position feedback signals indicative of the translational position of the gantry <NUM> and support column <NUM> on the base <NUM>, such as from a linear encoder.

The base <NUM> may include a cover <NUM> to protect the internal components of the base <NUM>. The cover <NUM> may be made of a flexible material and may be wound on a spool <NUM> as shown in <FIG>. The spool <NUM> may be enclosed within a housing <NUM> located at an end of the base <NUM>. One end of the cover <NUM> may be attached to the platform <NUM> and/or the support column <NUM> (e.g., using hooks or similar attachment mechanism). The spool <NUM> may be spring-loaded to maintain a suitable tension on the cover <NUM>. As the support column <NUM> translates away from the housing <NUM>, the cover <NUM> may be extended from the housing <NUM> by being unwound from the spool <NUM> and as the support column translates towards the housing <NUM> the cover <NUM> may be retracted into the housing <NUM> by being wound onto the spool <NUM> (e.g., similar to the operation of a roller shade for windows). The base <NUM> may include a pair of covers <NUM> attached to opposite sides of the support column <NUM>, where the covers <NUM> extend and retract from opposite sides of the base <NUM> as the support column <NUM> translates. <FIG> illustrate the base with extending/retracting covers <NUM> attached to the support column <NUM>.

<FIG> illustrate a gantry <NUM> of a multi-axis imaging system <NUM> according to an embodiment. <FIG> is an exploded view of a gantry <NUM> that illustrates an outer shell <NUM> of the gantry, a rotor <NUM> and a bearing assembly <NUM>. The outer shell <NUM> may comprise a high-strength structural material, such as aluminum. The outer shell <NUM> may have an outer circumferential wall <NUM> that may extend around the periphery of the gantry <NUM> to enclose the rotating components of the gantry <NUM> (e.g., x-ray source, detector, etc.), which may be attached to the rotor <NUM>. The outer shell <NUM> may also include a side wall <NUM> that may extend from the outer circumferential wall <NUM> to a bore <NUM> of the gantry <NUM> and may enclose the rotating components around one side of the rotating portion. The side wall <NUM> may form a first outer face <NUM> of the gantry <NUM> and may at least partially define the size of the bore <NUM> of the gantry. A lip portion <NUM> may extend from the outer circumferential wall <NUM> around the interior periphery of the gantry shell <NUM>. The lip portion <NUM> may provide a mounting surface of the bearing assembly <NUM>, as described further below. The lip portion <NUM> may be offset from the second outer face <NUM> of the gantry <NUM> by a distance sufficient to accommodate at least a portion of the bearing assembly <NUM> inside the outer circumferential wall <NUM> of the gantry shell <NUM>.

The outer shell <NUM> of the gantry <NUM> is shown in a partial cutaway view through the outer circumferential wall <NUM> in <FIG>. As shown in <FIG>, the outer circumferential wall <NUM> may have a larger cross-section thickness at a proximal end <NUM> of the gantry <NUM> where the gantry <NUM> is attached to the support column <NUM> than at the distal or unsupported end <NUM> of the gantry <NUM>. The proximal end <NUM> of the gantry <NUM> may include a generally circular-shaped flange portion <NUM> that may be attached to the outer race <NUM> of the rotary bearing <NUM> shown in <FIG>.

One or more openings <NUM> may be provided through the outer circumferential wall <NUM> as shown in <FIG>. The openings <NUM> may provide air-flow cooling of the components within the gantry <NUM>. In one embodiment, a first set of one or more openings 712a may be located at the proximal end <NUM> of the gantry <NUM> and a second set of one or more openings 712b may be located at the distal end <NUM> of the gantry <NUM>. One or more fans (not illustrated) may be located adjacent to the second set of opening(s) 712b and may operate to suck ambient air in through the first set of opening(s) 712a, over the components within the gantry <NUM> and out through opening(s) 712b. Alternately or in addition, one or more fans may be located adjacent to the first set of opening(s) 712a and may blow air through the gantry <NUM> and out through opening(s) 712b. In further embodiments, the direction of airflow may be reversed, such that air is sucked into the gantry <NUM> through opening(s) 712b and exits the gantry <NUM> through openings <NUM>(a).

The bearing assembly <NUM> according to one embodiment is shown in <FIG> and <FIG>. <FIG> is an exploded view showing the bearing assembly <NUM> attached to the rotor <NUM>. <FIG> illustrates the assembled gantry <NUM> in a partial cut-away view showing the bearing assembly <NUM> attached to the rotor <NUM> and to the gantry shell <NUM>. As shown in <FIG>, the bearing assembly <NUM> includes a first race <NUM> that is attached to the lip portion <NUM> of the outer shell <NUM> of the gantry <NUM>, and a second race <NUM> that is attached to the rotor <NUM>. A bearing element is provided between the first race <NUM> and the second race <NUM>, and is configured to allow the second race <NUM> (along with the rotor <NUM> to which it is attached) to rotate concentrically within the first race <NUM>, preferably with minimal friction, thereby enabling the rotor <NUM> to rotate with respect to the outer shell <NUM> of the gantry <NUM>. In the embodiment of <FIG> and <FIG>, the second race <NUM> may be a separate component that is firmly secured around the outer circumference of the rotor <NUM> (e.g., using mechanical fasteners). Alternately, the second race <NUM> may be formed as an integral part of the rotor <NUM>.

In various embodiments, the first race <NUM> of the bearing assembly <NUM> may be mounted to the outer shell <NUM> of the gantry <NUM> using a limited suspension system. The suspension system may be configured to accommodate a limited amount of bending/deflection of the cantilevered gantry <NUM> between the proximal <NUM> and distal <NUM> ends of the gantry <NUM> while ensuring that the bearing assembly <NUM> rotates within a plane. The present inventors have discovered that attaching an imaging gantry <NUM> to a support structure <NUM> at only one end of the gantry <NUM> in a cantilevered manner may result in a small amount of deflection or bending of the gantry <NUM> due to the gravity-induced bending moment of the gantry <NUM>. When the gantry <NUM> is rotated out-of-line with the vertical support column <NUM>, such as for performing a vertical scan as shown in <FIG> or a scan along a tilted axis as shown in <FIG>, the direction of gantry <NUM> deflection may include a component that is normal to the scan plane of the imaging components (e.g., x-ray source and detector) rotating within the gantry <NUM>. This downward curve or bend of the gantry and bearing on which the rotating components rotate may introduce a sufficiently large "wobble" effect to these components as they rotate between the proximal <NUM> and distal <NUM> ends of the gantry <NUM> to negatively affect image quality of the scan.

Various embodiments include a limited suspension system between the gantry shell <NUM> and the bearing assembly <NUM> to provide a small amount of compliance between these components in the direction of gantry deflection such that the bearing assembly <NUM> may continue to rotate in a plane when the gantry shell <NUM> is subject to gravity-induced deflection. In the embodiment of <FIG>, this may be achieved by attaching the bearing assembly <NUM> to the gantry shell <NUM> at a limited number of attachment points and allowing the portion of the bearing assembly <NUM> proximate to the distal end <NUM> of the gantry <NUM> to effectively "float" over a limited range with respect to the gantry shell <NUM>. In the embodiment of <FIG>, the lip portion <NUM> of the gantry shell <NUM> is attached to the first race <NUM> of the bearing assembly <NUM> in four locations around the periphery of the gantry <NUM>. It will be understood that the disclosed embodiment is merely exemplary and various embodiments may include more than or less than four attachments points between the gantry shell <NUM> and the bearing assembly <NUM>.

In the embodiment of <FIG>, the lip portion <NUM> of the gantry shell <NUM> may be fastened to the first race <NUM> of the bearing assembly <NUM> in two locations 707a, 707b that are more proximate to the proximal end <NUM> of the gantry <NUM> than to the distal end <NUM> of the gantry <NUM>. The two locations 707a, 707b are visible in <FIG>. The two locations 707a, 707b may be located on opposite sides of the gantry <NUM> and may be equidistant from the proximal end <NUM> of the gantry <NUM>. The lip portion <NUM> may be rigidly fastened to the first race <NUM> at locations 707a, 707b using mechanical fasteners, such as a screw <NUM> that may pass through an opening <NUM> in the lip portion <NUM> and into an opening <NUM> (e.g., a threaded opening) in first race <NUM>. A pair of washers 711a, 711b may be located between the bottom surface of the lip portion <NUM> and the top surface of the first race <NUM> and between the top surface of the lip portion <NUM> and the head of the screw/bolt <NUM>, respectively. The screw <NUM> may be tightened against the top surface of the lip portion <NUM> (via washer 711b) to rigidly and securely attach the lip portion <NUM> to the first race <NUM> at locations 707a, 707b, as shown in the cross-section view of <FIG>. Washer 711a may provide a small gap between the bottom surface of the lip portion <NUM> and the top surface of the first race <NUM>, as shown in <FIG>.

The bearing assembly <NUM> may be suspended from the gantry shell <NUM> at two additional locations 713a, 713b that are more proximate to the distal end <NUM> of the gantry <NUM> than to the proximal end <NUM> of the gantry <NUM>. <FIG> and <FIG> illustrate the attachment of the lip portion <NUM> of the gantry shell <NUM> to the first race <NUM> of the bearing assembly <NUM> at location 713a. The lip portion <NUM> may be attached to the first race <NUM> at location 713b in the same or similar fashion as shown in <FIG> and <FIG>. Location 713b may be located on the opposite side of the gantry <NUM> from location 713a. Locations 713a and 713b may be equidistant from the distal end <NUM> of the gantry <NUM>. In embodiments, attachment locations 707a and 713a may extend along a secant line <NUM> of the circular gantry <NUM>. The secant line <NUM> may be parallel to a midline of the gantry <NUM> extending from the proximal end <NUM> to the distal end <NUM> of the gantry <NUM>. Attachment locations 707b and 713a may extend along a second secant line of the gantry <NUM>, where the second secant line may also be parallel to the midline extending between the proximal <NUM> and distal ends <NUM> of the gantry <NUM>. The first and second secant lines may be equidistant from the midline.

<FIG> is an exploded view of the components used to attach the lip portion <NUM> to the first race <NUM> at location 713a. <FIG> is a cross-section view showing the lip portion <NUM> attached to the first race <NUM> at location 713a. As shown in <FIG> and <FIG>, the lip portion <NUM> and first race <NUM> may be attached using a mechanical fastener, such as a screw <NUM>, that may be similar or identical to the screw <NUM> used to fasten the lip portion <NUM> to the first race <NUM> at locations 707a, 707b. The screw <NUM> may pass through a relatively large diameter opening <NUM> in the lip portion <NUM> of the gantry shell <NUM>. A metal (e.g., steel) plate <NUM> having a slot <NUM> may be attached to the bottom surface of the lip portion <NUM> using mechanical fasteners (e.g., screws or bolts). The bottom surface of the lip portion <NUM> may include a recess <NUM> surrounding the opening <NUM> to accommodate the plate <NUM>. The slot <NUM> may be oriented along the direction of gravity-induced deflection of the cantilevered gantry <NUM>. For example, the slot <NUM> may extend along the secant line <NUM> of the gantry <NUM> that intersects attachment locations 707a and 713a.

A bushing <NUM>, which may be a bronze bushing, may be located within the slot <NUM> of the plate <NUM>. The bushing <NUM> may be dimensioned slightly smaller than the slot <NUM> along the length of the slot <NUM> so that there is some degree of compliance between the bushing <NUM> and the plate <NUM> in the direction of gantry deflection. This is illustrated in the cross-section view of <FIG>. There may be less compliance between the bushing <NUM> and the plate <NUM> along the width of the slot <NUM>. Thus, the bushing <NUM> may be held tight between the side walls of the slot <NUM> when the gantry <NUM> is rotated up into the configuration of <FIG> (e.g., for performing a horizontal scan). A first washer <NUM>, which may be a bronze washer, may be located between the bottom surface of the plate <NUM> and the top surface of the first race <NUM>, and may surround a central opening <NUM> through the bushing <NUM>. A second washer <NUM>, which may also be a bronze washer, may be located on the top surface of the plate <NUM> and may surround the central opening <NUM> through the bushing <NUM>. A Belleville spring washer <NUM> may be located above the second washer <NUM> and may surround the central opening <NUM> through the bushing <NUM>. A third washer <NUM>, which may be a steel washer, may be located above the Belleville spring washer <NUM>.

The screw <NUM> may be inserted through the third (e.g., steel) washer <NUM>, the Belleville spring washer <NUM>, the second (e.g., bronze) washer <NUM>, the central opening <NUM> of the bushing <NUM> and the first (e.g., bronze) washer <NUM> and into an opening <NUM> (e.g., a threaded opening) in first race <NUM>. The screw <NUM> may be fastened against the top surface of the plate <NUM> (via washers <NUM>, <NUM> and <NUM>) to attach the plate <NUM> to the first race <NUM> at location 713a, as shown in <FIG>. The plate <NUM> may be sandwiched between the first and second washers <NUM> and <NUM>. The spring washer <NUM> may be pre-loaded to maintain the entire stack in compression. The plate <NUM> may be separated from the top surface of the first race <NUM> by a gap <NUM> defined by the first washer <NUM>. A second gap <NUM> may separate the bottom surface of the lip portion <NUM> from the top surface of the first race <NUM> as shown in <FIG>.

The attachment configuration shown in <FIG> and <FIG> may provide a secure attachment between the gantry shell <NUM> and the first race <NUM> of the bearing assembly <NUM> while allowing the gantry shell <NUM> to bend or deflect over the bearing assembly without transferring any bend or curvature in the gantry shell <NUM> to the bearing assembly <NUM>. This may be achieved by suspending the bearing assembly <NUM> from the gantry shell <NUM> in a limited number of attachment locations that are sufficiently spaced to adequately support the bearing assembly <NUM> and the rotor <NUM> as it rotates within the gantry <NUM>. This contrasts with prior attachment techniques in which the bearing assembly <NUM> is rigidly secured to the gantry shell <NUM> at regular intervals (e.g. every <NUM>-<NUM>° or so) around the periphery of the gantry <NUM>. In addition, the gap <NUM> provided between the lip portion <NUM> and the first race <NUM> at the distal-most attachment points 713a, 713b may be sufficient to prevent the lip portion <NUM> from imparting a bending force on the first race <NUM> at the distal end <NUM> of the gantry <NUM>. Thus, bearing assembly <NUM> may remain flat over the entire gantry <NUM> even when the gantry shell <NUM> bends due to gravity.

This is schematically illustrated in <FIG>, which is a side view of a cantilevered gantry <NUM> mounted to a support column <NUM>. It will be understood that <FIG> is not necessarily to scale and is intended to provide an exaggerated view of the amount of bending of the gantry <NUM>. For example, for an x-ray CT system, the amount of gantry deflection between the fixed (proximal) and free (distal) ends of the gantry may be <NUM>-<NUM> or less. As shown in <FIG>, by suspending the bearing assembly <NUM> for the rotor from the gantry shell <NUM> at a plurality of spaced-apart locations as described above, the bearing assembly <NUM> is not influenced by the curvature of the gantry shell <NUM>. Thus, the bearing assembly <NUM> and the rotor may rotate in a plane <NUM>, as illustrated by the dashed line. The plane <NUM> of rotation of the bearing assembly <NUM> and rotor may be tilted from a horizontal plane, as shown in <FIG>. This tilt may be corrected for in the software used to process the image data obtained by the imaging system.

Alternately or in addition, the tilt angle of the plane of rotor rotation may be compensated for by mounting the gantry <NUM> at an angle with respect to the support column <NUM>. For example, the carriage <NUM> to which the gantry <NUM> is attached may have an angled front surface that compensates for the tilt angle of the rotor so that the scan plane is horizontal.

<FIG> illustrates a rotor <NUM> for an x-ray CT imaging system having a plurality of components mounted thereto. The system may be a multi-axis system <NUM> as described above. The rotor <NUM> may rotate within a gantry <NUM>, and may be mounted within the gantry <NUM> on a bearing assembly <NUM> as described above with reference to <FIG>. In particular, the rotor <NUM> may be mounted to the second race <NUM> of the bearing assembly <NUM> shown in <FIG> using suitable fasteners, such as bolts or screws.

The rotor <NUM> shown in <FIG> includes an x-ray source <NUM>, a high-voltage generator <NUM>, a heat exchanger <NUM>, an x-ray detector <NUM>, a power supply <NUM> (e.g., battery system), a computer <NUM>, a rotor drive mechanism <NUM>, and a docking system <NUM> (e.g., for providing intermittent power/data connection between rotating and non-rotation portions of the system). It will be understood that the components described and illustrated are merely exemplary, and other embodiments may omit one or more of these components and may utilize other additional components. For example, in embodiments, power for the rotating portion <NUM> may be provided by a slip ring or cable system, so that a power supply <NUM> on the rotating portion <NUM> may not be needed. In some embodiments, power and/or data may be continuously transferred between the rotating and non-rotating portions via cable, slip ring or wirelessly, in which case the power supply <NUM>, computer <NUM> and/or docking system <NUM> may not be included. Further, the rotation of the rotor may be provided by a drive system on the non-rotating portion, in which case the rotor drive mechanism <NUM> on the rotor <NUM> may not be included. Also, it will be understood that other types of imaging systems, such as MRI systems, may use other suitable components for imaging, as are known in the art.

In embodiments, the x-ray source <NUM> and detector <NUM> may be configured to perform a helical x-ray CT scan. The detector <NUM> may comprise a plurality of x-ray sensitive detector elements arranged in a semicircular arc, with the arc center coinciding with the focal spot of the x-ray source. In some embodiments, the x-ray detector may be a flat panel detector, and the system may be configured to perform real time x-ray fluoroscopic and/or cone beam imaging of an object within the bore of the gantry.

In the embodiment of <FIG>, during an imaging scan, the rotor <NUM> rotates within the interior of the gantry, while the imaging components such as the x-ray source <NUM> and x-ray detector <NUM> obtain imaging data for an object positioned within the bore <NUM> of the gantry, as is known, for example, in conventional X-ray CT scanners. The rotor drive mechanism <NUM> may drive the rotation of the rotor <NUM> around the interior of the gantry <NUM>. In embodiments, the rotor drive mechanism <NUM> may include a drive wheel <NUM> that engages with a belt <NUM>. The belt <NUM> may extend around the gantry <NUM> on a circular rail <NUM> that may be fixed to the side wall <NUM> of the gantry shell <NUM> (see <FIG>. The rotor drive mechanism <NUM> may be controlled by a system controller that controls the rotation and precise angular position of the rotor <NUM> with respect to the gantry <NUM>, preferably using position feedback data, such as from an encoder device.

<FIG> illustrate methods of operating an imaging system <NUM> to perform an imaging scan of a patient <NUM> according to various embodiments. The patient <NUM> may be located on a patient support <NUM> (e.g., a patient table) as described above. A control system <NUM> (e.g., a processor and memory) may be operatively coupled to the patient support <NUM>, as schematically illustrated in <FIG>. The control system <NUM> may be located partially or completely within the patient support <NUM> (e.g., within the linkage member <NUM>) and/or within one or more separate components, such as a workstation, the imaging system <NUM> or a mobile cart. The control system <NUM> may receive positon feedback data (e.g., rotary encoder data) from the patient support <NUM> and may send control signals to the motor(s) of the patient support <NUM> to cause the motor(s) to move the patient support <NUM> into a desired configuration. The configuration of the patient support <NUM> may be a pre-set configuration (e.g., stored in the memory of the control system <NUM>) and/or the configuration may be controllably adjusted by a user using a suitable user input device (e.g., buttons, joystick, pendant controller, computer keyboard and/or mouse, touchscreen display, etc.).

The multi-axis imaging system <NUM> may also include a control system <NUM> (e.g., a processor and memory). The control system <NUM> may be coupled to and control the operation of the first drive mechanism <NUM>, the second drive mechanism <NUM> and the third drive mechanism <NUM> to cause the relative translation and rotation of the gantry <NUM> with respect to the support column <NUM> and base <NUM> as described above. The control system <NUM> may also receive position feedback signals indicative of the relative positions and orientations of the gantry <NUM>, support column <NUM> and base <NUM>, such as from one or more encoders. The control system <NUM> may also control the operation of the imaging components within the gantry <NUM>, and may for example, issue command signal(s) to perform an imaging scan.

The control system <NUM> may be located within the multi-axis imaging system <NUM>, such as within the support column <NUM> and/or within one or more separate components, such as a workstation or a mobile cart. In some embodiments, the control system <NUM> for the multi-axis imaging system <NUM> may be co-located with the control system <NUM> of the patient support <NUM>. For example, control systems <NUM> and <NUM> may be implemented as separate processes (e.g., software applications) which run on the same computing device.

The control system <NUM> for the multi-axis imaging system <NUM> may be coupled to the control system <NUM> for the patient support <NUM> via a communication link <NUM>. The communication link <NUM> may enable the control system <NUM> for the patient support <NUM> to transmit data regarding the configuration of the patient support <NUM> to the control system <NUM> for the multi-axis imaging system <NUM>. In embodiments, the communication link <NUM> may be a bi-directional link, and the control system <NUM> for the multi-axis imaging system <NUM> may send data to the control system <NUM> for the patient support <NUM> indicating the configuration of the multi-axis imaging system <NUM>.

In various embodiments, the control systems <NUM>, <NUM> for the multi-axis imaging system <NUM> and the patient support <NUM> may communicate over communication link <NUM> so that each of these components may always know where the other one is relative to it. This may provide an important safety feature to prevent the imaging system <NUM> from colliding with the patient support <NUM> or a patient supported thereon. In embodiments, the multi-axis imaging system <NUM> and the patient support <NUM> may be "electronically geared" such that a movement of one of these components may cause a pre-determined counter-movement of the other component. In one embodiment, the control system <NUM> for the patient support <NUM> may be the "master" controller and the control system <NUM> for the imaging system <NUM> may be the "slave" controller. In other words, a movement of the patient support <NUM> may cause the control system <NUM> of the imaging system <NUM> to control the system <NUM> to make a corresponding counter-move.

<FIG> illustrate various motions of the patient support <NUM> and multi-axis imaging system <NUM>. In <FIG>, the patient support <NUM> may be in a position for loading or unloading of a patient. The imaging system <NUM> may be in a standby or "home" position with the support column <NUM> and gantry <NUM> translated away from the patient support <NUM>. The gantry <NUM> may be rotated in-line with the support column <NUM>. The standby or "home" position of the imaging system <NUM> may inhibit a collision between the imaging system <NUM> and the patient or the patient support <NUM>. The patient support <NUM> in various embodiments may be lowered to a position as shown in <FIG> so that the second portion <NUM> of the patient support <NUM>, which can support the patient in a lying position, is at a comfortable height for loading and unloading of the patient. For example, the second portion <NUM> may be at a height of no more than about <NUM>, such as between <NUM> and <NUM> from the floor. This may allow a patient to easily climb onto or be lowered down onto the patient support <NUM>, which may be convenient and safe for both the patient and the medical staff members.

The patient support <NUM> may then be raised from the lowered position of <FIG> to a height suitable for an imaging scan (e.g., such that the patient support <NUM> may be positioned within the bore of the gantry <NUM>). <FIG> illustrates the patient support <NUM> raised such that it is aligned with the bore of the gantry <NUM>. In this configuration, the imaging system <NUM> is ready to perform a horizontal scan of a patient in a lying position. The patient support <NUM> may be raised or lowered to a suitable height for performing a scan. <FIG> illustrates the patient support <NUM> raised to a maximum height for performing a scan of a patient supported in a horizontal lying position. The control system <NUM> of the imaging system <NUM> may send control signals to the first drive mechanism <NUM> to cause the gantry <NUM> to translate vertically on the support column <NUM> in coordination with the movement of the patient support <NUM> so that the bore of the gantry <NUM> remains aligned with the second portion <NUM> of the patient support <NUM>. In some embodiments, the control system <NUM> of the imaging system <NUM> may also send control signals to the third drive mechanism <NUM> to cause the support column <NUM> and gantry <NUM> to translate along the base <NUM> to maintain a pre-determined separation between the gantry <NUM> and the tip end of the second portion <NUM> of the patient support <NUM> as the patient support <NUM> is raised and/or lowered. In some embodiments, gantry <NUM> may move to maintain the outer face of the gantry <NUM> separated from the tip end of the of the second portion <NUM> of the patient support <NUM>. Alternately, the gantry <NUM> may move to maintain the tip end of the second portion <NUM> at least partially inside the bore of the gantry <NUM>.

When the patient support <NUM> is moved to a desired configuration, the control system <NUM> of the patient support <NUM> may send a signal to the control system <NUM> of the imaging system <NUM> indicating that the system is ready to perform a scan. The control system of the imaging system <NUM> may send control signals to the third drive mechanism <NUM> to cause the support column <NUM> and gantry <NUM> to translate along the base <NUM> and over the patient support <NUM> to perform a scan in a horizontal direction, as shown in <FIG>. In some embodiments, the patient support <NUM> may be prohibited from moving until the scan is complete.

To perform a scan along a tilted axis such as shown in <FIG>, the patient support <NUM> may be pivoted upwards as shown in <FIG>. In response to the movement of the patient support <NUM>, the control system <NUM> of the imaging system <NUM> may control the first, second and third drive mechanisms <NUM>, <NUM>, <NUM> to perform a coordinated motion of the gantry <NUM> as shown in <FIG>. In particular, the second drive mechanism <NUM> may rotate the gantry <NUM> relative to the support column <NUM> to maintain the bore axis of the gantry <NUM> aligned with the tilt angle of the patient support <NUM>. The first and third drive mechanisms <NUM> and <NUM> may translate the gantry <NUM> in both a vertical and horizontal direction to maintain the bore of the gantry <NUM> in alignment with the tip end of the patient support <NUM>. The gantry <NUM> may maintain a pre-determined separation distance from the tip end of the patient support <NUM> follows the position of the patient support <NUM>. In some embodiments, gantry <NUM> may move to maintain the outer face of the gantry <NUM> separated from the tip end of the of the second portion <NUM> of the patient support <NUM>. Alternately, the gantry <NUM> may move to maintain the tip end of the second portion <NUM> at least partially inside the bore of the gantry <NUM>.

When the patient support <NUM> is moved to a desired tilt angle, the control system <NUM> of the patient support <NUM> may send a signal to the control system <NUM> of the imaging system <NUM> indicating that the system is ready to perform a scan. The control system of the imaging system <NUM> may send control signals to the first and third drive mechanisms <NUM> and <NUM> to perform a coordinated vertical and horizontal translation of the gantry <NUM> and perform a scan along a tilted axis, as shown in <FIG>. In some embodiments, the patient support <NUM> may be prohibited from moving until the scan is complete.

To perform a scan in a vertical direction such as shown in <FIG>, the patient support <NUM> may be pivoted upwards as shown in <FIG> and <FIG>. In response to the movement of the patient support <NUM>, the control system <NUM> of the imaging system <NUM> may control the first, second and third drive mechanisms <NUM>, <NUM>, <NUM> to perform a coordinated motion of the gantry <NUM> as shown in <FIG> and <FIG>. In particular, the second drive mechanism <NUM> may rotate the gantry <NUM> relative to the support column <NUM> to maintain the bore axis of the gantry <NUM> aligned with the tilt angle of the patient support <NUM>. The first and third drive mechanisms <NUM> and <NUM> may translate the gantry <NUM> in both a vertical and horizontal direction to maintain the bore of the gantry <NUM> in alignment with the tip end of the patient support <NUM>. The gantry <NUM> may maintain a pre-determined separation distance from the tip end of the patient support <NUM> as follows the motion of the patient support <NUM>. In some embodiments, gantry <NUM> may move to maintain the outer face of the gantry <NUM> separated from the tip end of the of the second portion <NUM> of the patient support <NUM>. Alternately, the gantry <NUM> may move to maintain the tip end of the second portion <NUM> at least partially inside the bore of the gantry <NUM>.

When the patient support <NUM> is moved to vertical orientation as shown in <FIG>, the control system <NUM> of the patient support <NUM> may send a signal to the control system <NUM> of the imaging system <NUM> indicating that the system is ready to perform a vertical scan. The control system of the imaging system <NUM> may send control signals to the first drive mechanism <NUM> to translate the gantry <NUM> down the length of the patient support <NUM> to perform a vertical scan of the patient, as shown in <FIG>. In some embodiments, the patient support <NUM> may be prohibited from moving until the scan is complete.

In some embodiments, the patient support <NUM> may be moved to any arbitrary angle, and may enable the patient to be supported in Trendelenburg and/or reverse Trendelenburg positions. <FIG> shows the patient support <NUM> tilted down from a horizontal position to support a patient in a Trendelenburg configuration. The gantry <NUM> may be tilted on the support column <NUM> in the opposite direction from the patient support <NUM>, as shown in <FIG>. This may enable imaging of the patient through a variety of different anatomic planes, including, for example, a generally coronal plane (e.g., within ~<NUM>° of the coronal plane) through at least a portion of the patient's anatomy. This may be useful, for example, for ENT CT scans of the sinus and/or ears. Also, in brachytherapy, the patient support <NUM> and gantry <NUM> may be tilted to a configuration to enable scanning of the prostate region without needing to scan through the patient's femur.

Further embodiments include a multi-axis imaging system <NUM> that may be utilized for veterinary medicine. A multi-axis imaging system <NUM> may be used to perform imaging scans of animals, including large animals (e.g., livestock) and/or equine species, in a weight-bearing standing position. An example of the system <NUM> is shown in <FIG>. The system <NUM> in this embodiment is located on a mobile trailer <NUM>. However, it will be understood that the system <NUM> may be a fixed system located in a veterinary hospital/clinic, or another location such as a farm, ranch or zoo. The system <NUM> includes an imaging gantry <NUM> attached to a support column <NUM> in a cantilevered manner, as described above. The gantry <NUM> may be rotatable with respect to the support column <NUM> and may also translate along the length of the support column <NUM> in a vertical direction. Although not visible in <FIG>, the system <NUM> may also include a base <NUM> that supports the support column <NUM> and gantry <NUM>, and the support column <NUM> and gantry <NUM> may be translatable with respect to the base <NUM> in a horizontal direction. The system <NUM> may further include a support stage <NUM>. An animal <NUM>, such as a horse as shown in <FIG>, may be positioned on the top surface <NUM> of the support stage <NUM>. One or more ramp portions <NUM> may enable the animal <NUM> to easily climb up and down from the top surface <NUM>. A cavity <NUM> may be provided in the support stage <NUM> for housing the gantry <NUM>, as shown in <FIG>. The cavity <NUM> may have a shape that corresponds with the shape of the gantry <NUM>. When the gantry <NUM> is lowered into the cavity <NUM>, the outer side wall of the gantry <NUM> may be flush with the top surface <NUM>.

The gantry <NUM> may be raised up from the cavity <NUM> to perform a vertical scan of the legs of the animal <NUM> standing on the support stage <NUM>, as shown in <FIG>. An actuator system may optionally raise the bottom surface <NUM> of the cavity <NUM> up even with the top surface <NUM> of the support stage <NUM> in coordination with the raising of the gantry <NUM>. This may prevent the animal <NUM> from accidentally stepping into the cavity <NUM>. Following the scan, the gantry <NUM> may be lowered back into the cavity <NUM>, and the animal <NUM> may climb down from the support stage <NUM>.

<FIG> illustrates the multi-axis imaging system <NUM> performing a scan of the neck of a standing animal <NUM>. The gantry <NUM> is raised out of the cavity <NUM> and positioned such that the neck of the animal <NUM> is located within the bore of the gantry. A control system for the imaging system <NUM> may control the system to perform a coordinated vertical translation of the gantry <NUM> along the support column <NUM> and a horizontal translation of the gantry <NUM> and support column <NUM> along the base <NUM> to scan along the neck of the animal <NUM>.

Various examples of diagnostic imaging applications that may be performed on a human or animal patient in a weight-bearing position using an embodiment multi-axis imaging system <NUM> include, without limitation:.

<FIG> is a system block diagram of a computing device <NUM> useful for performing and implementing the various embodiments described above. The computing device <NUM> may perform the functions of a control system <NUM> for a multi-axis imaging system <NUM> and/or a control system <NUM> for a patient support <NUM>, for example. While the computing device <NUM> is illustrated as a laptop computer, a computing device providing the functional capabilities of the computer device <NUM> may be implemented as a workstation computer, an embedded computer, a desktop computer, a server computer or a handheld computer (e.g., tablet, a smartphone, etc.). A typical computing device <NUM> may include a processor <NUM> coupled to an electronic display <NUM>, a speaker <NUM> and a memory <NUM>, which may be a volatile memory as well as a nonvolatile memory (e.g., a disk drive). When implemented as a laptop computer or desktop computer, the computing device <NUM> may also include a floppy disc drive, compact disc (CD) or DVD disc drive coupled to the processor <NUM>. The computing device <NUM> may include an antenna <NUM>, a multimedia receiver <NUM>, a transceiver <NUM> and/or communications circuitry coupled to the processor <NUM> for sending and receiving electromagnetic radiation, connecting to a wireless data link, and receiving data. Additionally, the computing device <NUM> may include network access ports <NUM> coupled to the processor <NUM> for establishing data connections with a network (e.g., LAN coupled to a service provider network, etc.). A laptop computer or desktop computer <NUM> typically also includes a keyboard <NUM> and a mouse pad <NUM> for receiving user inputs.

The foregoing method descriptions are provided merely as illustrative examples and are not intended to require or imply that the steps of the various embodiments must be performed in the order presented. Words such as "thereafter," "then," "next," etc. are not necessarily intended to limit the order of the steps; these words may be used to guide the reader through the description of the methods.

In one or more exemplary aspects, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on as one or more instructions or code on a non-transitory computer-readable medium. The steps of a method or algorithm disclosed herein may be embodied in a processor-executable software module executed which may reside on a non-transitory computer-readable medium. Non-transitory computer-readable media includes computer storage media that facilitates transfer of a computer program from one place to another. By way of example, and not limitation, such non-transitory computer-readable storage media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to carry or store desired program code in the form of instructions or data structures and that may be accessed by a computer. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of non-transitory computer-readable storage media. Additionally, the operations of a method or algorithm may reside as one or any combination or set of codes and/or instructions on a machine readable medium and/or computer-readable medium, which may be incorporated into a computer program product.

Claim 1:
A multi-axis imaging system (<NUM>), comprising:
an imaging gantry (<NUM>) with an imaging axis (<NUM>) extending through a bore (<NUM>) of the imaging gantry (<NUM>);
a support column (<NUM>) that supports the imaging gantry (<NUM>) on one side of the gantry (<NUM>) in a cantilevered manner;
a base (<NUM>) that supports the imaging gantry (<NUM>) and the support column (<NUM>);
a first drive mechanism (<NUM>) that translates the gantry (<NUM>) in a vertical direction relative to the support column (<NUM>) and the base (<NUM>);
a second drive mechanism (<NUM>) that rotates the gantry (<NUM>) with respect to the support column (<NUM>) between a first orientation where the imaging axis (<NUM>) of the imaging gantry (<NUM>) extends in a vertical direction parallel to the support column (<NUM>) and a second orientation where the imaging axis (<NUM>) of the gantry (<NUM>) extends in a horizontal direction parallel with the base (<NUM>); and
a third drive mechanism (<NUM>) that translates the support column (<NUM>) and the gantry (<NUM>) in a horizontal direction along the base (<NUM>);
characterized in that
the first drive mechanism (<NUM>) comprises a non-backdrivable drive system including a motor (<NUM>) geared into a lead screw (<NUM>) that extends along a length of the support column (<NUM>), and a carriage (<NUM>) connected with the gantry (<NUM>) comprising
a nut (<NUM>) fixed thereto that engages with the lead screw (<NUM>) such that a rotation of the lead screw (<NUM>) drives a translation of the carriage (<NUM>) and the gantry (<NUM>) in a vertical direction relative to the support column (<NUM>), the first drive mechanism (<NUM>) being non-backdrivable under normal operating loads.