Digital tomosynthesis imaging using fiber-based patient 3D positioning in standard radiography system

Abstract

A system (SYS) and related method for implementing tomographic imaging with a non-rotating radiographic imaging device (IA). In the event of relative movement between a patient (PAT) to be imaged and a detector (DM) or X-ray source (XS) of the imaging device, an input interface (IN) receives i) 3D position measurement readings acquired by a fiber-based system (OFS) via, for example, a set of fiber-based sensors (Si) arranged at the patient. The measurement readings may relate to gestures that can be taken by the patient during movement relative to the probe. Projection images (Lambda) of the patient during or before and after such relative movement, which can be acquired by an imaging device, are also received. A projection direction determiner (PDD) determines projection direction data (alpha) for the projection image (lambda) based on the 3D position measurement readings (P). Projection images associated with the projection direction data may be used for tomography.

Description

Technical Field

[0001] The present invention relates to a system for facilitating tomographic imaging using a radiographic imaging device, an imaging arrangement comprising such a system, a wearable for use with such a system, a related method, a computer program element and a computer-readable medium. Background Art

[0002] Medical imaging is one of the most important tools in medicine. It reveals images from within the patient's body to accurately inform medical tasks, including diagnosis, treatment, planning, and controlling the operation of other medical equipment.

[0003] X-ray-based imaging is a staple of medical imaging. Radiography is one such example, a time-honored method used since its inception over 100 years ago and still in use today. Radiography is projection imaging and therefore lacks depth of field. In some applications, this limitation is more than compensated for by a simple and cost-effective setup. Furthermore, in some applications, projection-only imaging is sufficient for purposes such as fracture detection and trauma settings.

[0004] However, for many other applications, more detailed spatial structure information is required, and image information along the third spatial dimension is needed. This is because intermediate structures (when encountered in purely projection-based imaging) can sometimes lead to occlusion of critical details.

[0005] Very different from radiography, tomography is a medical imaging technique in which multi-directional X-ray projection images are acquired around a region of interest ("ROI") and computationally combined to reveal a 3D volume of cross-sectional slices of the ROI (such as the lungs, bones, heart, abdominal organs, etc.), regardless of the medical task at hand. In some cases, such as in full-angle CT, such a tomographic volume provides full depth of view and maximum spatial information from all directions. Limited-angle tomography ("tomosynthesis"), which acquires projection images less than (sometimes slightly less than) 180°, also adds some depth of field information (sometimes called "2.5D" imaging, rather than 3D imaging such as CT), but to a lesser extent, which may nevertheless be sufficient in some cases (such as in dentistry or mammography, etc.).

[0006] Tomography / tomosynthesis can be used to diagnose different abnormalities / conditions, including chest imaging for lung nodule detection, head and neck imaging for paranasal sinuses, dental imaging for improved spatial resolution, musculoskeletal imaging for high-resolution imaging of complex fractures and some emergency situations. For example, Tomography / Tomosynthesis provides significantly improved visualization of pathological lesions (nodules) in the lung using digital tomosynthesis relative to projection-only radiography.

[0007] As useful and desirable as (X-ray) tomographic imaging (shorthand for CT or tomosynthesis herein) is, it does increase technical complexity, with all its disadvantages, including increased cost, and a higher risk of operational failure and damage.

[0008] Most imaging systems configured for tomography (such as CT scanners up to Generation IV, interventional imaging systems such as C-arms and U-arms, etc.) are rotational. This increases the cost of the complex mechanical arrangements required to achieve such rotational imaging. Some health systems face challenges with budget constraints and increasing demand. Due, at least in part, to the cost, in some locations, such rotational imaging equipment is unavailable. Summary of the Invention

[0009] Therefore, more cost-effective solutions related to tomographic imaging may be needed.

[0010] The objects of the invention are achieved by the subject-matter of the independent claims, wherein further embodiments are incorporated into the dependent claims. It should be noted that the aspects of the invention described below apply equally to an imaging arrangement comprising such a system, a wearable object for use with such a system, an associated method, a computer program element and a computer-readable medium.

[0011] According to a first aspect of the present invention, there is provided a system for facilitating (and in embodiments even enabling) tomographic imaging using a non-rotational radiographic imaging apparatus, comprising:

[0012] an input interface for receiving, when the system is in use and there is relative motion between a patient to be imaged and a detector or X-ray source of the imaging apparatus, i) 3D position measurement readings acquired by a fiber-optic based system via a set of fiber-optic based sensors, the set of fiber-optic based sensors being arranged at i.1) the patient (PAT) or i.2) the detector and / or source, wherein the measurement readings are capable of being correlated to a posture that the patient can adopt during motion relative to the detector or a posture of the source or the detector relative to the patient; and ii) projected images of the patient acquired by the imaging apparatus during, before, and after such relative motion;

[0013] a projection direction determiner configured to determine projection direction data for the projected image based on the 3D position measurement readings, and

[0014] An output interface is used to provide the projection image associated with the projection direction data for reconstruction.

[0015] In an embodiment, the system comprises a reconstructor configured to implement a tomographic reconstruction algorithm to reconstruct a tomographic image of a region of interest of the patient based on the projection images and the projection direction data associated with the projection images.

[0016] In an embodiment, the tomographic reconstruction algorithm comprises a tomosynthesis reconstruction algorithm.

[0017] In an embodiment, the set of fiber-optic based sensors is at least partially integrated in a wearable (WB) worn by the patient during imaging.

[0018] In an embodiment, the wearable object further comprises a detector of the imaging device.

[0019] In an embodiment, 3D position measurement readings are converted by the fiber optic based system through the length of the optical fiber forming the sensor from shape measurements representing shape changes experienced during patient motion or during motion of the source or detector.

[0020] In an embodiment, the relative patient motion is self-induced by the patient on command (without the use of equipment in the motion), or is induced by a rotating actuator on which the patient resides during imaging, or is induced by at least the X-ray source or the detector in the imaging device being moved past the patient.

[0021] In an embodiment, the X-ray source is tiltable so as to maintain alignment with the detector as the X-ray source is moved past the patient.

[0022] In an embodiment, the rotation facilitator comprises any one of the following: a swivel stool, a patient bed.

[0023] In an embodiment, at least part of the set of fiber-optic based sensors is arranged in a spatial configuration that is substantially maintained during patient movement.

[0024] In an embodiment, the projection direction data is determined based on a patient posture normal vector relative to a normal vector of a surface of the detector or a normal vector at the source, such as a normal to a surface of a housing of the source.

[0025] In an embodiment, the patient posture normal vector is determined as a normal to a plane defined by three or more reference 3D position readings of the 3D position measurement readings.

[0026] In an embodiment, there are three or more reference 3D position readings supplied by a reference sensor of a fiber-optic based sensor, which are arranged to form a polygon at the patient relative to the region of interest to be imaged or to form such a polygon at the detector or source. Similarly, the polygon can be arranged at the surface of the detector or the surface of the housing of the source, or arranged in another suitable and predefined manner. Circular or elliptical or other planar layouts are also contemplated herein.

[0027] In an embodiment, the reference sensors are arranged to form a triangle on the patient's torso.

[0028] In an embodiment, the fiber optic based system comprises a second set of sensors arranged at the detector.

[0029] In an embodiment, the fiber-optic based system comprises a second set of sensors or a third set of sensors arranged at the X-ray source of the imaging device.

[0030] In an embodiment, the set of fiber optic sensors at the detector extends to the X-ray source, thus connecting the detector and the X-ray source.

[0031] In an embodiment, the imaging device is of a mobile type, and the X-ray source of the imaging device is arranged on a wheeled or tracked frame, wherein the imaging device including the X-ray source of the imaging device can be moved past the patient on the frame of the imaging device during imaging.

[0032] In an embodiment, if the relative motion is not self-induced, the system may further comprise an immobilization device capable of substantially immobilizing at least the anatomy of the patient during imaging.

[0033] In an embodiment, the immobilization device comprises a mattress or pad formed of viscoelastic foam to receive at least said anatomy of the patient therein.

[0034] In an embodiment, the system may include a motion guidance system to guide the patient in performing their movements while self-inducing.

[0035] In another aspect, an imaging arrangement is provided, comprising an imaging device and further comprising at least one set of fiber-based sensors at a detector and / or at an X-ray source for use with a system according to any of the preceding embodiments, and / or the imaging arrangement further comprises a fiber-based system.

[0036] In an embodiment, the imaging arrangement further comprises at least a set of fiber optic sensors at the patient.

[0037] In an embodiment, the imaging arrangement further comprises the system of any one of the preceding embodiments.

[0038] In yet another aspect, a wearable for a patient is provided that includes a set of fiber optic sensors for tomographic imaging using a non-rotational radiographic imaging device.

[0039] In another aspect, a computer-implemented method for facilitating / enabling tomographic imaging using a non-rotational radiographic imaging device is provided; comprising:

[0040] receiving, when the system is in use and there is relative motion between a patient to be imaged and a detector or an X-ray source of the imaging apparatus: i) 3D position measurement readings acquired by a fiber-optic-based system via a set of fiber-optic-based sensors, the set of fiber-optic-based sensors being arranged at i.1) the patient or i.2) the detector and / or source, wherein the measurement readings are capable of being correlated to a posture that the patient can adopt during motion relative to the detector or a posture of the source or the detector relative to the patient; and ii) projected images of the patient acquired by the imaging apparatus during, before, and after such relative motion;

[0041] determining projection direction data for the projected image based on the 3D position measurement readings, and

[0042] The projection image associated with the projection direction data is provided for reconstruction.

[0043] In another aspect, a computer program element is provided which, when run by at least one processing unit, is adapted to cause the processing unit to perform the method.

[0044] In another aspect, at least one computer-readable medium having a program element stored thereon is provided.

[0045] This paper proposes an enabler system and method for tomographic imaging that can be retrofitted to existing radiographic systems to repurpose them for tomographic imaging, instead of or in addition to classic projection-only radiographic imaging. It comprises a set of optical fibers connected to a data processing system that converts shape or curvature measurements captured during motion of the patient or equipment into 3D position data, which can then be converted by a software- or hardware-based system into orientation information related to the relative rotation / motion of the patient during image acquisition. Data pairs of projected image frames and projection orientation data can then be used for tomographic purposes, as contemplated herein.

[0046] The proposed system or method facilitates or, more specifically, enables the performance of tomosynthesis or tomosynthesis using only a standard radiographic system (thus, one that cannot be moved like a C-arm). Tomographic imaging can be performed by fiber-optic-based 3D position and orientation determination of a relevant patient body part or the entire patient body. In some examples, the patient can be instructed to rotate the body part, with the angle of rotation recorded with each acquired X-ray image. Alternatively, in cases where patient movement would alter bony alignment (i.e., joint movement) or would otherwise be undesirable, the entire patient can be moved via a platform without altering the patient's anatomical alignment. A rotating chair or bed can provide such patient movement. Motors are not required, but can be used. Projected images can be interpolated to generate images corresponding to regular angular intervals, or the projected images can be used directly for tomosynthesis, such as in tomosynthesis. The relative motion need not necessarily be one of rotation, but can instead be a linear translation. In some embodiments, the patient is moving. Alternatively or additionally, the imager's X-ray source ("source") or detector is moved past the patient while the patient remains stationary.

[0047] Thus, in some embodiments, the system may include: i) a fiber optic based sensing system, wherein; ii) the position of relevant anatomical regions of the patient's body (points of curvature) and the position of a reference frame optionally attached to the detector can be determined; and iii) positional deviations of the patient can be detected and measured.

[0048] The proposed system and method allow i) tomosynthesis / tomography using standard radiographic systems, ii) retrofitting to existing radiographic systems without hardware changes for tomosynthesis / tomography, iii) providing an alternative mechanism for performing tomosynthesis / tomography.

[0049] A "patient" is the subject of imaging. Reference to a "patient" is not necessarily to the patient as a whole, but may refer to a portion such as a body part, an anatomical feature, an organ, a group of organs, a body region, etc. Thus, the subject of imaging may refer to such a portion, which is referred to herein as a region of interest (ROI). As used herein, a patient primarily refers to a human patient, but animals such as pets in veterinary applications are not excluded herein.

[0050] A "user" refers to a person who operates the imaging device or oversees the imaging procedure, such as a medical professional or other person. In other words, a user is typically not a patient.

[0051] "Posture" is used interchangeably herein with and refers to: the position and orientation of a body part, organ, or more generally, anatomical feature; or the position and orientation of equipment or parts (such as an X-ray source, detector, etc.) relative to a coordinate system (such as a "world" coordinate system, e.g., a particular agreed-upon location in an examination room). BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Exemplary embodiments of the present invention will now be described with reference to the following drawings, which are not drawn to scale unless otherwise specified, and in which:

[0053] Figure 1 shows a schematic block diagram of a radiographic system for tomographic imaging as contemplated herein in embodiments;

[0054] Figure 1A A rotational imaging system is shown;

[0055] Figure 2 It is an illustration of tomographic imaging based on the relative motion between the patient and the X-ray source;

[0056] Figure 3 is a perspective view of patient-induced motion for tomographic imaging as contemplated herein in embodiments;

[0057] Figure 4 is a schematic block diagram of a fiber-optic based 3D position measurement system;

[0058] Figure 5 shows a fiber optic system arranged at a patient and a detector for tomographic imaging based on patient-induced motion as contemplated herein in some embodiments;

[0059] Figure 6 shows a fiber optic system deployed at a patient or in a wearable as used in some tomographic imaging embodiments contemplated herein;

[0060] Figure 7is a schematic block diagram of an enabler system for tomographic imaging, as may be used in embodiments;

[0061] Figure 8 、 9 is a schematic block diagram of a fiber-optic based tomographic imaging arrangement according to further embodiments contemplated herein;

[0062] Figure 10 is a schematic diagram of a stopper apparatus as may be used herein in embodiments for tomographic imaging; and

[0063] Figure 11 A flow chart showing a method of implementing tomographic imaging by using a radiographic imaging apparatus is shown. DETAILED DESCRIPTION

[0064] First reference Figure 1 , which shows components of a medical imaging arrangement IAR as envisaged herein in embodiments.

[0065] The arrangement device IAR preferably comprises an imaging device IA, such as an X-ray based imaging device, preferably a radiographic imager configured for projection imaging. The imager IA is operable to acquire medical images of the patient's PAT during an imaging session, for example to assist in treatment and / or diagnosis. An example of this is as shown in Figure 1 Chest X-ray imaging is schematically shown in FIG, but imaging of other body parts or for other purposes is also contemplated herein.

[0066] The imaging arrangement IAR includes a computing system SYS implemented by one or more fixed or mobile computing devices or systems. The computing system SYS is operable to process projection images, such as those provided by the imager IA. Broadly speaking, the computing system SYS herein serves as an enabler system, allowing such a projection-only imager IA to be transformed into an imager with tomography capabilities. The system SYS can be retrofitted to various types of existing radiographic imagers IA. This will be explained in greater detail below, after providing some additional background on medical imaging, to better clarify the explanation of the enabler system SYS.

[0067] Typically, the imaging arrangement IAR may be located in an examination room of a medical facility (hospital), or may be used in an external environment, such as by rescue personnel, or in other medical rescue missions, disaster relief operations, and the like.

[0068] The medical imaging arrangement IAR includes an X-ray-based imaging device IA ("imager") having an X-ray source XS (such as an X-ray tube) and an X-ray-sensitive detector module DM (sometimes referred to herein simply as the "detector" for brevity). During imaging, the X-ray source XS is energized to generate an X-ray beam XB that emanates from a focal spot FS and passes through an exit window EW of a detector housing HS to interact with patient tissue PAT as it passes through the patient PAT while the patient PAT resides in an examination region ER between the source XS and the detector DM. The beam emerges distally from the patient and impinges on the X-ray-sensitive surface of the detector DM, which is composed of pixels. The detector can be of any type and kind, such as a flat-panel detector, in which the detector pixels are arranged in a matrix layout in rows and columns to define the X-ray-sensitive surface as a surface in 2D.

[0069] The radiation beam XB is modified during its interaction with tissue. The modified beam is then detected as intensities at the detector pixels of the detector module. Some of the detected intensities vary spatially across different detector pixels, and the detected intensities therefore represent a projected image of internal anatomical structures, tissue, etc. The intensities are converted into a digital image via A / D conversion, which can then be stored in an image memory MEM or displayed on a display device DD after visualization via a visualizer VIZ. The visualizer can form a graphical display based on the projected image, or such image can be processed in other ways as required by the medical task at hand.

[0070] like Figure 1 As illustrated, the imaging device IA is preferably of the radiographic type and is therefore based solely on the projected images described. The radiographic device IA may be of a fixed type, for example mounted in an examination room. For example, the X-ray source may be wall-, ceiling- or floor-mounted in a fixed frame structure. The mounting may allow some alignment options, such as translation or tilt, as illustrated by the angle β. This allows alignment of the beam XB with the region of interest ("ROI") of the patient to be imaged. The field of view ("FOV") may be adjusted in this way. Likewise, the detector module DM may be ceiling-, floor- or wall-mounted, as desired in a similar frame structure, stand or the like. The detector DM so mounted may also allow, for example Figure 1 Some form of positional orientation modification, such as translation in the x and / or y direction, some tilting, etc., as indicated by the arrows in . Figure 1 Herein, the orientation, position, posture, etc. of the components of the imager IA may be referenced to an imaging coordinate system (x, y, z). The axis z may generally indicate the imaging axis, ie, the direction of propagation of the main or central X-ray beam XB.

[0071] Such a fixed type imaging arrangement IA as described can be used for example for chest X-rays, where the patient is typically required to stand in the examination area during imaging. Between the source XS and the detector DM, there may be suitable floor markings to help the patient find the correct general position in the room.

[0072] As an alternative to the fixed type room-confined radiographic imaging apparatus IA as described above, the imager IA may be configured as a mobile type. In such a mobile type imager IA, at least the X-ray source is mounted in a mobile frame, mounted on a cart or other rail-type or wheeled mobile frame structure FR (see Figure 8 , which will be discussed in more detail below). Such a mobile imager IA can be freely moved around the room by the staff, or from room to room, in order to provide more flexibility in imaging patients (e.g. those who are too frail to enter an examination room). In some such mobile imagers IA, the detector module DM can provide free and cordless handling without physical attachment, except for possible cables for image data transmission, but even this can be replaced by a wireless image data transmitter. Such a detector module DM can typically be a square or rectangular plate (but can be of any form factor) which can be positioned behind the patient. For example, a detector module DM of this type can be used for bedridden patients who are too frail to sit or stand. The cordless detector module DM is placed for use behind the patient, essentially being clamped between the patient and the top of the bed when in use. The generally wheeled frame structure RF (again see Figure 8 ) is positioned by the user, wherein the source XS is aligned as described above for the fixed imager, and projection images can then be acquired, also as substantially described above for the fixed imager.

[0073] An imaging arrangement IAR using a fixed or mobile imager IA may include a patient support PS positioned in the examination region ER. Such a patient support PS may include a table structure, couch, or the like, on which the patient may lie during imaging, or on which the patient may position an ROI (such as a limb) for musculoskeletal imaging. The imaging arrangement is configured so that the ROI / patient resides on the support PS and between the source XS and the detector module DM.

[0074] If it were not for the proposed imaging enabler system SYS (which will be discussed in more detail momentarily), then a radiographic imager IA of either type (fixed or mobile) would only be able to be used for projection imaging. Figure 1AUnlike the other imaging systems shown, these other imaging systems are specifically configured for rotational tomographic imaging. In such systems, the X-ray source SS and the detector DT are rigidly connected in a gantry G. The gantry is journaled JR, which allows the source SS and the detector DT to rotate around the examination region, where the ROI / patient is located, as shown in FIG. Figure 1A This allows the acquisition of projection images from multiple directions, which can be combined by a tomographic reconstruction algorithm to reveal a cross-sectional or 3D volume image of the ROI. Such a reconstructed image is different from a projection image that is part of the projection domain (detector), whereas the reconstructed image is in the image domain, i.e., part of the 3D space in the examination region ER. Figure 1A Such a tomograph rotational rig as shown is more expensive in terms of parts, maintenance, and Figure 1 Simpler radiographic devices IA with fewer (or sometimes no) moving parts are more susceptible to malfunctions and defects. For example, rotational tomography systems (such as Figure 1A CT scanners or C-arm imagers (e.g., those in the field) require: an expensive gantry G setup, which holds the X-ray source SS and detector DT; a slip ring arrangement for data transmission; and a journal JR, which has a complex and costly ball bearing arrangement to allow for smooth rotation during imaging. Furthermore, in such systems designed for tomographic imaging, the rotation needs to be tracked, which necessitates a complex electromechanical rotary encoder component ENC. This encoder component ENC tracks the rotational motion of the gantry G by recording the associated angles. The recorded angles are then correlated with images acquired at different such angular orientations before the acquired projection data and their recorded angles are transferred for reconstruction.

[0075] Therefore, as envisioned in this paper Figure 1 Non-rotational radiographic systems in Figure 1A Unlike the rotation system in the , which was designed and intended for tomographic imaging from the outset. Of course, the radiographic imager IA as envisaged herein in the embodiments is repurposed for tomographic imaging without requiring any of the aforementioned high-cost and error-prone parts such as journals JR, encoders EC, slip rings, rotatable gantry with source and detector, etc. Instead, a largely software-based enabler system SYS is provided herein that enables similar Figure 1 Radiographic systems (and their equivalents) can be used for tomographic imaging.

[0076] Broadly, in terms of hardware components, the enabler system SYS comprises or cooperates with a 3D position measurement system OFS, preferably based on optical fibers, which collects such measurements related to the patient's PAT during imaging. Broadly, the enabler system SYS processes the 3D position measurement system provided by the system OFS to enable tomographic imaging. Thus, even existing radiographic systems (of the fixed or mobile type) that were originally configured only for projection imaging can now be used. Figure 1 ) can also be retrofitted by the proposed enabler system SYS, thereby repurposing such a radiographic imager IA for tomographic imaging in a cost-effective and flexible manner. The system can be at least partially installed in the operator console OC of the imager IA, or in fact in any computing device, such as a smartphone, tablet, laptop or their "stationary counterparts" such as desktop computers, workstations, etc.

[0077] In the current reference Figure 2 、 3 The proposed tomography enabler SYS for use in a radiography arrangement IA is conceptually illustrated in FIG.

[0078] First reference Figure 2 And continue to refer to Figure 1 , 3D position measurement system OFS uses an arrangement device / system of optical fibers, which Figure 1 Schematically shown in FIG as sensors Sj along respective optical fibers Fj (j=1, 2). Three such optical fibers F1-3 are shown, one for the detector, one for the source XS, and one for the patient PAT, respectively, but in some embodiments, it may be sufficient to have only one set of such sensors S1 arranged in a single or multiple optical fibers F1 at the patient. When referring to such sensor / fiber(s) as typically used by a 3D position measurement system OFS, the reference numerals "F", "S" are used herein.

[0079] In the proposed imaging setup IAR, the patient PAT undergoes a rotational motion, either self-induced or promoted by a rotation promoter RF. In the case of self-induction or self-propelled, the patient can, for example, stand in the examination region and rotate around the rotation axis (see Figure 1 The axis of rotation is substantially coincident with the longitudinal (craniocaudal) axis of the patient. Figure 2 A, B and Figure 3 This rotational movement of the patient is directed towards a fixed source XS and a fixed detector DM, as illustrated in the perspective view in . Instead of self-induction, such patient movement can be facilitated by a technical device acting as a rotation facilitator RF, such as a swivel chair or some such technical device.

[0080] During rotational patient movement, the fiber-optic based system collects 3D positioning information via an optical fiber F1 arranged at the patient. As the patient is changing his posture, a shape measurement stream is generated by the optical fiber F1 in response to the shape changes of the optical fiber F1 caused by the rotation or other movements of the patient. The shape measurement stream is passed from the optical fiber F1 to a data processing system unit SSP of the 3D position measurement system OFS. The data processing system unit SSP calculates 3D position information in 3D space of certain points on the portion of the optical fiber F1 arranged at the patient based on the (shape) measurement stream. The system SYS can convert the 3D position measurements into direction, angle data, such as Figure 2 As shown, the projection direction data α1, α2, and α3 correspond to different postures of the patient PAT. Figure 2 The patient posture corresponding to two instances of projection direction data α1 , α2 , α3 is illustrated in perspective views A) and B) of FIG. , wherein the patient PAT resides in front of the detector module DM. Figure 2 The views provided in are views along the imaging axis Z, which extends to Figure 2 DM and extends towards the detector DM.

[0081] Either self-propelled or facilitated, the patient's PAT is centered around its longitudinal axis ( Figure 1 As the fixed X-ray source XS is rotated (dashed line in FIG), the fixed X-ray source XS is excited and the detector DM is operated to acquire a series of projection images λi=1-3. Some or each projection image λi is associated with corresponding projection direction data α1, α2, α3, as recorded by the fiber-optic based (3D) position measurement system OFS at the corresponding time of acquisition of the corresponding projection image. Therefore, each projection image ("frame") λj is associated with a corresponding direction angle αj. In this way, a dual data stream λj, α is generated. Therefore, the angle tracking data λj, α so associated allow any existing tomography algorithm to be used to reconstruct a volume or cross-sectional image V therefrom for storage, viewing or other processing as required. It should be noted that such angle tracking does not require expensive, error-prone and maintenance-intensive encoders ENC, rotation-set CT or C-arm setup ( Figure 1A For example, such a projection frame λj and angle association α can be achieved by using the time stamp / tag t granted by the imager and the position measurement system OFS for their respective measurements.

[0082] Generally, in most cases, it can be expected that the patient PAT will perform a limited angle rotation, in which case a tomosynthesis reconstruction algorithm may be more appropriate. However, this article does not exclude the possibility that the patient PAT will perform at least 180 degrees of rotation. 0rotation (even 360° or more) to allow calculation of the full tomographic 3D volume using any of a range of standard reconstruction algorithms such as FBP (Filtered Back Projection), algebraic, iterative, etc.

[0083] Figure 3 Shown with Figure 2 Same concept as in, but in a partially from above perspective, while the patient PAT undergoes rotation (self-induced or facilitated), thereby taking Figure 3 A, B and C indicate different postures in the sequence.

[0084] The patient PAT may be guided in its rotational movement by the motion guidance system MGS to encourage a correct, ie uniform, rotation about its longitudinal axis as accurately as possible, preferably maintaining the rotational axis parallel to the image plane of the detector DM throughout the entire rotation.

[0085] The motion guidance system MGS can be configured to provide sound or audio prompts through a speaker system. In addition or alternatively, the motion guidance system MGS can be video-assisted, as preferably contemplated herein. For example, a video stream can be displayed on a display device. The video information can represent the outline of a moving portrait that the user is encouraged to follow. It is conceivable to use a full-size screen for shadow playback, onto which the outline of the expected moving video is projected. A projector video source behind the patient can project the patient's shadow on the screen together with the outline of the expected movement. The patient is then encouraged to follow the guidance so that their shadow conforms to the outline in the projected video. However, a video stream can be used alternatively or additionally, which is displayed as, for example, computer graphics on any display device. For example, a virtual avatar is moving on a computer display that shows the optimal movement trajectory and its deviation. Many variations of the motion guidance system MGS are contemplated herein in the embodiments, as long as they are configured to guide the patient to follow the target rotational movement.

[0086] As mentioned, rotational movement of the patient during imaging may not necessarily be completely self-induced, but may be facilitated. Figure 1As shown, the patient can alternatively sit on a swivel chair or swivel stool RF or other rotation facilitator RF, and the chair or stool rotates in a motorized manner or more preferably under inertia after an initial force input (such as a push from the ground, a gentle nudge, etc.) given by the user or the patient himself. Another option is to have a rotating platform inserted into the floor of the examination area, preferably flush with it. For example, a circular platform can be propelled by a motor, or preferably in this article, by the patient or medical user using inertia again after an initial pulse input. Once the platform is in motion, imaging can be started to collect angle tracking projection data as described above. When using such a rotation facilitator R (whether it is a stool, chair or floor-inserted platform), the patient can take any desired basic posture (such as sitting upright, standing, squatting) as needed, and imaging is continued while the patient on it rotates around its axis due to inertia, etc. A movable platform in the floor may require considerable expense, which is less preferred in this article for a tomographic imaging enabler system SYS, OFS that can be easily modified, such as contemplated herein. In particular, a simple swivel stool or swivel chair, with or without a headrest, backrest, or armrests, can be purchased from any office furniture outfit at minimal expense and may be sufficient for the present purpose.

[0087] Thus, in its basic form, the proposed adaptable tomography enabler system includes the described projection direction data processing system, which can run on a computer such as a laptop or desktop computer, or indeed on any computing device, handheld or non-handheld. Additionally, interfacing with a fiber-based 3D position measurement system OFS is preferred, as described in more detail below. The interfacing can be wireless or wired, as desired. Reconstruction computations can be performed locally on the system SYS, but can also be outsourced or offloaded, for example, to a server, workstation, etc. Thus, the system can be advantageously deployed in a client-server or cloud infrastructure. Thus, the local portion of the system at the imager IA may simply involve coordinating the collection of data λjα, while reconstruction can be performed elsewhere, such as on a more powerful server computer. The data λjα is dispatched to such a server or other computing system, workstation, etc., which implements the reconstruction algorithm. Upon reconstruction, the reconstructed image V can then be returned for local viewing, processing, storage, control purposes, etc.

[0088] In the current reference Figure 4 , the 3D position measurement system OFS is described in more detail in various embodiments.

[0089] Broadly and preferably, optical shape sensing is preferred herein for an optical fiber based 3D position measurement system OFS, but other non-invasive and non-ionizing shape sensing principles and techniques are not excluded herein.

[0090] In an embodiment, a 3D position measurement system OFS includes a shape sensing device SSD comprising the aforementioned shape sensing processing unit SSP and a plurality of sensors S. The sensors S are preferably defined in or on a deformable, elongated component of the sensor device (such as a probe, arm, etc.), but in either case are defined along the deformable, elongated component. The shape sensing device is preferably based on optical light, in which case the probe or arm can be implemented as a length of one or more of the aforementioned optical fibers F, F1-3, as previously described. Preferably, multiple such optical fibers can be used, each defining a separate set of sensors. Preferably, at least two, more than two, or all of the optical fibers are coupled to the same shape sensing processing unit SSP, and their shape sensing readings are processed together to produce an output result. The optical fibers F can have a circular, elliptical, or other such cross-section, or can alternatively be arranged flat, for example as a ribbon, strip, or strip. Suitable such optical fibers are described in the applicant's US2009 / 0137952.

[0091] One way in which the patient PAT, detector MD or source XS may be measured is by arranging a first set of sensors Si of the shape measurement device SSD (also referred to herein as "patient sensors") relative to the patient, in particular in spatial relationship to the region of interest.

[0092] Optionally, a second set of such sensors Sj (also referred to herein as "auxiliary sensors") is arranged in a spatial relationship with the detector module DM. The auxiliary sensors with respect to the detector module may be arranged at or on the mobile DM, or may be integrated into the mobile DM. However, it may be sufficient that the sensors are arranged in a previously known spatial relationship, and the arrangement of the second set of sensors Sj is not necessarily at the detector, but rather elsewhere in the examination room or at other parts of the X-ray imager IA. Hereinafter, references to "fiber F" may be considered to be references to a corresponding set of sensors constituting at least part of the fiber F.

[0093] During posture changes, the portion of the feed line FL of the optical fibers F, F1-3 extending from the patient, source or detector (wherein the plane is defined by the optical fiber layout as described above) to the data input interface of the shape sensing processing unit SSP undergoes a deformation DF (see Figure 6 A), wherein the deformation DF) is shown.

[0094] This deformation causes light traveling through the optical fiber to be internally reflected with a specific reflection pattern related to the deformation of the optical fiber F. Therefore, the reflection pattern can be related to the curvature experienced by the optical fiber along its length. As each sensor or point along the length of the optical fiber experiences its own positional curvature, a set of corresponding curvature values (one for each sensor) can be provided as output.

[0095] The shape sensing processor may calculate 2D or preferably 3D point coordinates as output from the curvature values. However, such conversion is not required and the output may instead be provided as curvature data. In practice, the format or nature of the output data is immaterial in this context, as long as the output data indicates the 3D position of a point along the optical fiber F in 3D space relative to a world coordinate system (X; Y; Z). The output data may relate to stress or strain measurements. In Figure 4 The basic operation of the above optical shapes is illustrated in the block diagram of A).

[0096] An input signal X controls a light transmitter TX to transmit light LT through an optical fiber F. A cross-section of the core of such an optical fiber is shown, and it should be understood that more than one such core may be present, twisted, braided, or bundled, and thus combined in other ways to form an optical fiber. A cross-section of an optical fiber having a core C and an optional cladding region buffer in which the core is enclosed is shown. Light traveling through the optical fiber F undergoes total (internal) reflection and is received at a light detector RX to generate an output measurement signal representing the reflection pattern experienced by the light and can be correlated with the shape of the optical fiber and, therefore, the body posture resulting from the attachment of the optical fiber to the relevant body part, as described above. The reflection pattern can be processed by a processor SSP into the indicative output signal. The processor SSP can include a solver to solve a set of Frenet-Serret equations based on the shape measurements (stress, strain, or curvature values) to obtain output data indicative of the shape and / or 3D position representing the posture.

[0097] Similar readings can be received from an optional second optical fiber F2 (e.g., coupled to a detector module) to provide a second stream of shape sensing readings that can be processed together with the stream of shape readings from the first optical fiber F1 to more robustly compute a pose relative to the detector module DM. It is also possible to use a single or multiple optical fibers disposed only at the patient, in which case the optical fiber(s) F2 need not be disposed relative to the detector module DM.

[0098] It will be appreciated that in some embodiments, the sensors Si,j may be discretely arranged as a set of fiber Bragg grating (FBG) sensors, but this is not necessarily required in all embodiments, as other technologies are also contemplated. For example, the sensors may comprise point locations or positions along the optical fiber, and thus not necessarily discrete components / structures as in FBGs or the like, but rather a quasi-continuous linear arrangement of point locations along the core C of the optical fiber.

[0099] In other arrangements, the FBGs of each core are not necessarily spread out evenly over the length of the core, but are arranged towards the end portion of the respective core or elsewhere along the respective length of the respective core. Preferably, there are multiple fiber cores per optical fiber F, such as 2 or 3 or more. 3 cores are sufficient for good results in 3D, but 2 may be sufficient in some cases. Therefore, reference herein to a set of sensors S may be interpreted as reference to a respective plurality of cores of an optical fiber F and / or a plurality of FBGs in a core, or to other arrangements in or at (one or more) optical fiber cores that enable shape measurement.

[0100] Specifically, the light emitted through an optical fiber can be used to estimate the 3D curvature of the plane in which the optical fiber is placed. In this process, light of different wavelengths is emitted through the optical fiber, and the phase difference and arrival time (TOA) are calculated. From these phase differences and TOA, an approximation of the curvature points of the plane is derived. Alternatively, the mentioned FBG-based sensors are used. Each point on the curvature can be defined by a tuple (x, y, z) representing the position vector in 3D space. Sending different wavelengths can be done in single mode ( Figure 4 C) (where a single ray of a given wavelength is emitted at a time) is done sequentially, or by using multimode fiber ( Figure 4 B) where light at different wavelengths is sent down the optical fiber F simultaneously.

[0101] Therefore and preferably, the shape sensing processing unit SSP is configured to be able to interrogate the shape / curvature of the optical fiber F, and therefore the 3D point coordinates of any point along its length, in particular to reveal the corresponding 3D position coordinates of 3 points AC1-3 at the patient or detector DM or source XS.

[0102] The end portion of the optical fiber F that terminates at the patient, source, or detector is the distal end, while the other end portion (proximal end) of the optical fiber F (which is the end at which the feeder portion of the optical fiber terminates) is fed into the shape sensing processing unit SSP at an interface, for example, via a suitable fiber optic cable socket, plug, etc. Each FF1-3 may include a system of multiple, possibly interconnected optical fibers.

[0103] Typically, during sensing operations, the reference point may comprise an inflection point on the fiber core. The shape sensing mechanism typically monitors the corresponding angle formed at the inflection point. If a second set of sensors at the detector is used, as is preferred herein, the alignment of the angle with the reference frame is monitored. In addition to the set of sensors Si at the patient, the reference frame is also defined by a second set of sensors Sj at the detector.

[0104] It should be understood that Figure 4The embodiment of a shape sensing device SSD in an AC is merely an example, and other arrangements are contemplated herein, so long as shape measurements that can be correlated with posture changes can be obtained substantially as described herein. Optical or infrared light is used herein, but other frequencies in the non-ionizing range are also contemplated herein.

[0105] In summary, the signal processing system SSP may thus be able to convert shape and / or curvature measurements of the optical fiber(s) F1 (or, if used, F2, F3) into 3D coordinates of a point in 3D space (X, Y, Z) relative to a world coordinate system. In particular, 3D point position information may be acquired relative to any reference point in the examination room. The optical fiber-based 3D position measurement system OFS may be configured in an initial calibration phase by calibrating its readings relative to a selected world reference origin of the coordinate system.

[0106] As mentioned above, the operation of the tomography enabler system SYS, OFS envisages the placement of one or more optical fibers F1 at the patient, in particular at a location such as Figure 5 B shows the layout in more detail, and now continues with reference to Figure 5 Reference Figure 5 B.

[0107] The patient optical fiber F1 may comprise three strands of optical fiber arranged to terminate at their distal ends at their endpoints, thereby defining three or more anchor points AC1, AC2, AC3, as shown in FIG. Figure 5 B. However, any predetermined point on the optical fiber F1 (strand) may be used instead. Therefore, the term "(optical) fiber" as used herein does not mean that it is a single fiber, although it may be good in some arrangements, but multiple fibers may be formed, such as Figure 5 、 6 As shown, each fiber acts individually or in combination, and each fiber can interrogate shape change / position information along its respective length. Alternatively, in practice, a single such fiber (strand) is used and extended in a layout to define three anchor points AC1-3.

[0108] The optical fiber F1 is preferably arranged at the patient so that there is no mutual movement or displacement between the three points AC1-3 during rotation of the patient. In one embodiment, this can be achieved, for example, by Figure 5 A and Figure 6This is accomplished by arranging the optical fibers into a suitable geometric shape defining at least three anchor points AC1-3 as shown. For example, the optical fiber F1 may extend in a triangular layout on the back of the patient's torso. The three anchor points AC1-3 thus form the vertices of a triangular layout, wherein the distal portion of the optical fiber 1 (the feeder portion FL of the optical fiber F1) extends from the patient's back, e.g., along the floor, to connect at an interface with the processor SSP of the 3D position measurement system OFS, thereby providing shape measurements for processing there. For example, the triangle may be formed by the points AC1-2 at the shoulder blades, with the point AC3 at the lower lumbar portion of the spine. Other configurations of the anchor point layout are also envisaged herein, as long as they allow for the (preferably unique) definition of a plane (the "patient plane"), for reasons that will soon become apparent.

[0109] Although the mutual constellation of the 3 anchor points does not change, the feedline portion of the optical fiber will undergo some shape change during rotation of the patient, such as some form of twisting, etc. Such shape change can be converted by the processor SSP into a stream of 3 individual 3D position coordinate readings, one such stream for each anchor point AC1-3.

[0110] The patient plane defined by (at least) three anchor points AC1-3 can be calculated by analytical geometry methods. Given the three plane definition points AC1-3, the plane defines the normal to the patient plane. and can be easily calculated.

[0111] In a similar vein and in some optional embodiments, a second similar set of optical fibers F2 of the 3D position measurement system OFS may be arranged at the detector DM to define a reference plane relative to the detector DM there. For example, the "detector fibers" F2 (as they may be referred to herein) may extend around the edge of the detector module to define three or more points therein (not shown), and thus define a plane with its own normal vector (reference vector V R ) reference plane.

[0112] At appropriate time increments during patient motion, the two normal vectors V R 、V P The angle between the two (one at the detector plane and the other at the patient plane) can change and thus reveal projection directions α1, α2, α3, etc. over time, as described above in Figure 2 and 3 As described in , wherein the associated projection frames are acquired to produce a dual angle v frame data stream λj, α. Thus, the projection data can be calculated on geometric grounds based on the changing mutual spatial constellation of the two normal vectors and thus the jointly changing angle α between them. The normal can be located in a planar layout (e.g., as Figure 5B) is at the centroid C of the triangle (or other) layout). It can be envisioned that the detector normal Other reference positions for the normal are also feasible in this paper, not limited to the center of mass.

[0113] exist Figure 6 The reference detector plane is sketched in A. Specifically, Figure 6 A shows a view along the imaging direction z, where the patient PAT is in front of the detector module. The triangular arrangement of anchor points A1-A3 is defined by, for example, the patient optical fiber F1 and a feeder portion FL of the optical fiber extending from the patient's back. Alternatively, arrangements of the optical fiber F1 on the front of the patient (chest) or around the patient's head are also contemplated herein in embodiments. For example, the optical fiber F1 may be arranged around parts of the front and parietal bones. The optical fiber F1 may be integrated into a wearable WB, such as in a headband. Three or more anchor points may be placed about 120° apart around the upper skull portion of the patient's head. However, this and other optical fiber F1 layout arrangements at the patient may not need to be uniform in all embodiments. Figure 6 Yet another embodiment is shown in FIG. B, in which optical fibers F1 define three or more anchor points AC1-AC3 and are integrated into another type of wearable WB, such as an upper torso garment, shirt, or hospital gown. This and other wearable WBs described herein can be worn by the patient during imaging. The optical fibers F1 are suitably integrated therein so that, when the wearable WB is so worn, it adopts the triangular layout shown or another suitable plane-defined layout. Given the height and build of different patients, it may be necessary to provide wearable WBs of different sizes. Yet another patient-specific optical fiber F1 arrangement contemplated herein is arranged around the patient's hips, for example, as a belt WB.

[0114] Alternatively, the anchor points of the optical fiber F1 may be attached to the patient's skin by means of adhesive pads, different from those used for electrodes when performing ECG, for example.

[0115] In embodiments where the imager is of the mobile type, the detector module DM may be integrated into a wearable article, such as into the back covering portion of a robe or shirt. For example, the detector module may be sewn into the fabric, or may be attached by hook and loop fasteners such as Velcro. TM The detector may be so integrated with the optical fiber, or replace the optical fiber.

[0116] Now refer to Figure 7 , which shows a schematic block diagram of a retrofittable tomography enabler system SYS as contemplated herein.

[0117] The fiber-optic-based system OFS is provided with at least one (in embodiments, two or three) channels CH1-CH3 for shape or curvature measurements, which are transformed into 3D position information (3D coordinates relative to a world coordinate system) of anchor points on the patient and, optionally, also on the detector plane. The 3D positions of the points define the patient plane and, optionally, the detector plane. Each plane can be defined by a respective set of three anchor points. A third channel CH3 for a third optical fiber can be additionally arranged at the source XS in either embodiment (single fiber F1 or dual fiber arrangement F1, F2), as will be explained in more detail below.

[0118] If the detector DM is (substantially) always stationary during imaging (or at least if the detector plane is not tilted during imaging), the reference normal V to the detector plane is R is a fixed predefined parameter and therefore no detector fiber F2 is required and there is only a single channel fiber input from the patient fiber F1.

[0119] At least three anchor points ACj (the anchor points at the detector or source are not specifically shown in the figure) include the 3D coordinates P of each channel = (X AC i , Y AC i , Z AC i ) is received at the input port IN and then parsed by the projection data determiner PDD into projection direction data α, as described above. In particular, the position 3D information of the projection direction α can be obtained by the two reference vectors V P 、V R The projection direction data are calculated at the corresponding angles α between α and α, and this calculation of α is preferably performed at the imaging frame rate. Thus, a stream of projection direction data α=αt is generated during patient rotation and imaging.

[0120] The projection direction data α are output at the output port OUT. The data α can be associated with the corresponding acquired projection frame λt acquired during the patient rotation. Thus, the associator component at the output port associates each or some angle data αt with the corresponding frame λt to thus form a two-channel data stream (λt, αt) = λj, α. A timestamp can be used for this association. The projection data αt can be inserted into the corresponding projection frame λt as metadata (header data, etc.), such as it can be done for DICOM or similar formats. The frame and angle pair data (λt, αt) = λj can be stored in a memory MEM of one or more computing systems PU of the operating system SYS.

[0121] Preferably, and as primarily contemplated herein, the associated frame and angle pair data (λt, αt) = λj are first passed to a tomographic reconstructor RECON, which uses a tomographic or tomosynthesis algorithm to generate volumetric cross-sectional slice images V. Depending on the need, the entire volume or just one or more slice images can be generated. The tomographic images V can be visualized on a display device DD by suitable rendering software, either in real time during the imaging session or later during review by a radiologist, for example, as needed and upon request.

[0122] Optionally and additionally, the frame and angle convection data (λt, αt) = λj may be stored in a memory MEM for later analysis, statistical analysis or for educational purposes and / or may itself be visualized by a visualizer VIZ on a display device DD.

[0123] Based on precise 3D position measurements received from the fiber-based position measurement system OFS, the imager IA (particularly its source XS or detector DM) can be corrected for any unwanted motion or incorrect patient rotation during imaging by the optional corrector module CORR. The corrector's operation can also be based on such position / posture measurements received via the aforementioned third / second optical fiber F3 disposed at the source XS. The optical fiber F3 can extend between the source XS and the detector D, or between the source and the patient. In practice, the third optical fiber F3 can connect any one or more of the patient, source, and detector in any combination. This arrangement again derives a third / second normal vector at the "source plane" in a plane-defining manner. The distal portion of the optical fiber F3 can be suitably disposed at the source XS housing HS, for example, to define such a plane with at least a reference point, similar to the patent regarding the source plane. The corrector's operation is based on calculating the deviation angle between relevant normals (such as the detector DM normal and the source XS normal). Based on this deviation angle, a correction can be applied to the data (λt, αt) = λ, as described above. Additionally or alternatively, the correction may be used to indicate to the user visually or via audio that there is a misalignment. If the rotation speed is not uniform, or if the patient rotation axis is not parallel to the detector plane, the patient rotation is considered incorrect herein. In terms of correct source-detector alignment, this is preferably such that the imaging axis z extends from the focal spot FS to the detector DM plane and intersects it perpendicularly and preferably at the center point of the imaging plane of the detector. Any misalignment may be picked up and corrected by the corrector CORR based on calculating the angle between the detector normal VR and the normal at the source, similar to the above for the normal V R 、V P described.

[0124] Now refer to Figure 8 and Figure 9The alternative radiographic imaging arrangement in , which is repurposed and enabled for tomographic use by the enabler system SYS herein. Such use is also based on a similar fiber-optic based 3D position measurement system OFS as described above. However, Figure 8 、 9 The embodiments in the present invention do not necessarily rely on patient-induced motion, as this may not always be appropriate, for example for the elderly, people in the ICU, or people who have undergone surgery and are waking up in a recovery room, etc.: in short, for all people who are too weak for self-propelled physical motion, especially people who are confined to a prostate body position for any reason ( Figure 9 ).

[0125] In such cases, it may be useful to move the X-ray source XS relative to the patient PAT rather than to move the patient relative to the source XS, as described above. In such cases, in order to still enable tomographic imaging using the radiographic system along the above principles, it is preferred herein to move the X-ray source XS relative to the patient PAT, as described above. Figure 1 Described in and Figure 8 、 9 The mobile type radiographic imager IA is shown in FIG. The frame FR of the mobile imager IA on which the source XR is mounted is moved, for example, by a staff member past the patient. The scanning path may be straight, along the edge of the bed PS on which the patient lies ( Figure 9 ), or along any other line through a moving patient. In a chest X-ray ( Figure 9 ), the frame FR on which the active XS is mounted can be moved past the patient. In this embodiment, the patient PAT may still be standing, sitting, etc. in the examination room. This arrangement may be suitable for patients who cannot move or rotate due to limited mobility, or who are not expected to follow movement instructions with the necessary level of compliance and accuracy (e.g., children), as previously described, for example, with respect to Figure 4 This may be desirable in the described situation. For better illustration, the scanning path of the source XS along positions x=j x1, x2, ..., xN is shown in plan view. At each position xj, a corresponding projection frame λ is acquired. The scanning path does not have to be curved around the patient but can also be straight, for example for tomosynthesis applications.

[0126] In these embodiments, the positional 3D data from which the associated angular data α are calculated by the system FS are also collected by optical fibers F, F2, F3, which are arranged at the source XS and the detector DM and in a plane-defined layout at each, as shown above. Figure 3As explained above. Preferably, an optical fiber F extends from the source XS to the detector DM. This connection F allows sensing of angular deviations between the source and detector normals. A single optical fiber may be used and run as F, F2, F3 between and at the source XS and the detector DM, or a system of two or three interconnected optical fibers may be used. Figure 9 A similar arrangement is shown in FIG, wherein the patient is in a prone position on a bed PS, with the detector module DM sandwiched between the patient PAT and the bed top, as previously described. In this embodiment and other embodiments (such as in Figure 1 In the fixed-type imager IA), the detector module DM may include an anti-scatter grid AGS.

[0127] The one or more optical fibers F, F2, and F3 thus arranged are all routed via one or more feeder sections FL to feed channels CH1-CH3 into a data interface of a fiber-based 3D position measurement system, wherein a projection direction determiner PDD of the system SYS calculates angular projection direction data α based on the angle between the source and detector normals. The joint measurement results received from the optical fibers (sections) F, F1, and F2 are preferably used herein to accurately determine the projection angle.

[0128] The mutual movement between the tube and the detector module will be recorded by the optical fiber F connecting the two components (source and detector modules), and this can also be converted into projection direction data. Specifically, the interconnection F between the source XS and the detector DM undergoes shape changes during the imaging movement between the source and the detector. From these shape changes, the deviation angle between the two normals (at the source and the detector) can be calculated, and thus the projection direction can be calculated. Having a single optical fiber running between the two components (source and detector) is one embodiment, but it is also envisaged herein to have two separate optical fibers F, F2, both of which are fed into the OFS system as two channels.

[0129] The angle data α are likewise associated with the acquired projection frames λ, which are then fed into the reconstructor RECON for tomographic reconstruction, as described above.

[0130] exist Figure 8 、 9In the above examples of , some form of simple motorization may be considered, such as an electric motor in a track-mounted or at least semi-robotic embodiment, integrated into a cart or any kind of chassis on which is mounted a frame holding the source XS. The imaging robot can be programmed to travel along a scan path past the patient, for example, in a curved scan path around the patient. However, this may also require hardware expenditure, which may be undesirable. Therefore, instead, staff moving the source XS past the patient by pushing or pulling a wheeled chassis supporting the source XS on its frame FR may be all that is required to implement some form of tomographic imaging herein, whether or not it is only tomosynthesis, where only a relatively short scan (straight or curved) path through the patient needs to be traced.

[0131] It is also contemplated herein to steer the source XS of the mobile imager in an arc around the ROI (possibly facilitated by wheels WH with a movable axis of rotation, as simple as castors / swivel wheels) to achieve more tomographic imaging results.

[0132] In the above embodiment Figure 8 、 9 In the embodiment of the present invention, the X-ray source XS can be angled so that it maintains alignment with the detector module, although this is arbitrary. Preferably, the angle and movement are manually caused by the clinical user.

[0133] As should be understood, although Figure 8 、 9 The embodiments in use some form of motion by the X-ray source XS, but the embodiments Figure 8 、 9 None of them require the complex encoder scheme ENC, journal JRL and slip rings required for the tomograph rotation system, as previously described in Figure 1A As discussed in .

[0134] It will be readily appreciated that the roles of the mobile source XS and the fixed detector DM may be reversed, and application scenarios are contemplated herein where the detector DM moves relative to the fixed source.The fiber-based principles described above apply equally to such embodiments.

[0135] exist Figure 8 、 9In this embodiment, the optical fiber F1 is not required at the patient PAT, which can remain stationary in this embodiment, which can be useful, for example, for imaging elderly or bedridden patients. Similarly, if the source XS or the detector DM remains fixed (at least not tilted), and only one component XS, DM is moved, then no optical fiber is required at the fixed component DM, XS. Thus, in some embodiments, the source XS is fixed and the detector DM moves around the patient in an arc, straight line, or other scanning path, although a straight line or arc is preferred because the tomographic processing is greatly simplified. In either case, the manner and process of movement should preferably be predefined.

[0136] This movement can be accomplished by clinical staff who move the source XS around the patient in an arc while keeping the detector with its radiation-sensitive surface facing the patient PAT. The user may need to wear special protective hazard gear that shields against X-radiation, which may be impractical in most environments. Therefore, it is preferred that the source XS be moved by staff instead and walked around or past the patient in an arc or straight line, as described above.

[0137] Figure 10 Shows that it can be Figure 9 or a similar embodiment, in which it is assumed that the patient PAT is lying still while the source XS passes through the patient. The stop device ID can be arranged as a mattress or pillow, a cushion-type object, made of thermoplastic foam. Such a foam responds by deformation if touched or lying on it. Upon contact, the foam material displaces and forms a depression DP, which is a negative shell of the contacting anatomical structure (such as the patient's hand as shown). The depression DP conforms to the shape of the body part and forms a slightly raised pit CR-like material boundary around it. The foam hardens in this displaced state, and the remaining depression DP is able to hold the body part firmly in place during imaging. The stop device ID can be arranged as, for example, a mattress on the patient support PS, or as an operating table arranged in the examination area between the X-ray source and the detector. Viscoelastic polyurethane foam (memory foam) can be used, which adapts to the patient surface due to heat and pressure.

[0138] Now refer to Figure 11 , which shows a flow chart of a method implemented by a machine for performing tomographic imaging calculations using a radiographic X-ray imaging setup based on 3D measurements obtained from an optical fiber comprising a sensor and arranged at a patient. Optionally, the optical fiber or a second optical fiber is arranged at a detector. As another option, the optical fiber is arranged at the detector and / or at the X-ray source of the radiographic imaging device.

[0139] The radiographic imaging device is not of the rotary type, in particular, it does not comprise a rotatable gantry with a source and a detector rotatable about the ROI / patient, and / or does not comprise a rotary encoder on a journal rod. In short, the proposed method allows tomographic imaging with simple imaging equipment. In an extreme case, a fixed X-ray detector opposite a fixed X-ray source with the patient in between is sufficient for the proposed method. In this case, fiber optic measurements at the patient represent the 3D position of the patient's posture, for example, the patient is rotated about its longitudinal axis while being imaged to acquire projection data. The 3D position data from the fiber optic system can be converted into angular projection data representing the changed posture of the patient relative to the source or detector, which can be used together with the acquired projection data for tomographic reconstruction of slices or volumes of the ROI.

[0140] Patient motion may be rotational or alternatively linear, the latter being particularly useful for tomosynthesis reconstruction. However, patient motion is not necessarily required in all embodiments herein. Instead of patient motion, the source or detector is moved manually relative to the patient / ROI by a motor or by the user. Preferably, the source is moved linearly through the ROI or in an arc around the ROI, with an angular coverage of less than 180°, 180° or greater than 180°, as required. In the absence of patient motion, an optical fiber is arranged at the source or detector, or at both, to measure, in particular, the posture of the source relative to the patient, which can also be converted into projection direction data for use in tomographic reconstruction. Imaging can be performed during such relative patient motion relative to the source or detector, or can be performed in a "step & shoot" manner before and after incremental posture changes.

[0141] The arrangement of the optical fiber on / at the patient or on / at the detector or source can be implemented in a plane-defining manner, wherein the sensors in the optical fiber define at least three reference points and thus define corresponding planes at the patient, detector, or source. The angle between the normals to such planes (such as the patient plane and the detector plane, or the detector plane and the source plane) represents the angular projection direction data used in the tomographic reconstruction.

[0142] At step S1110, such 3D position measurements are obtained based on light transmitted by optical fibers arranged at or on the patient's body. The optical fibers can be arranged in a plane-defined manner, for example, on the patient's back or other anatomical structure. Optionally, the same or different optical fibers are arranged on the detector to define corresponding planes for the radiation-sensitive surface of the detector. Additionally or alternatively, the optical fibers can be arranged in a similar manner at the X-ray source.

[0143] In step S1120 , based on such 3D position measurement results, posture information representing the posture of the patient relative to the detector or source is calculated.

[0144] In some embodiments of step S1120, the 3D position measurements define planes, and their corresponding normals are calculated, one for the patient plane and one for the detector plane. However, in the case of a fixed detector module, the detector planes may be predefined, so in this case, since the detector normals are design constants, sensor measurements may not be received there.

[0145] In step S1130 , projection direction data is calculated based on the 3D position measurement results. Specifically, the deviation angle between two normal lines is calculated based on analytical geometry techniques to define the projection direction for a given moment.

[0146] At step S1140, either before or after step S1120, a projection image (a "frame" at time t) is obtained. In a preferred embodiment, but optional herein, the acquisition or projection data in the case of the (mobile) X-ray unit 1A is respiratory-gated to avoid parallax errors in tomosynthesis later. Preferably, a "step and shoot" acquisition protocol is used, wherein steps S1130, S1140 of projection direction data calculation and acquisition alternate: the patient is asked to move in increments, each increment being followed by an instance of steps S1130, S1140, etc. Continuous schemes are not excluded herein, as some tomography algorithms suitable for cone-beam / helical geometries are designed to cope with continuous acquisition protocols and may be suitably adapted for the present purpose as required.

[0147] At step S1150, the projection direction data so determined at S1130 is associated with the corresponding frame acquired at that time.Time stamps in the fiber optic system and imager can be used to facilitate the association between the projection direction data and the frames.

[0148] During steps S1130, S1140 or before and after any such one or more steps S1130, S1140, the patient is expected to move, either self-induced or by a facilitator such as a swivel stool, to acquire a stream of projection data frames associated with corresponding projection direction data caused by relative motion / posture changes between the patient and the detector and / or source.

[0149] At optional step S1160, in case the patient's movement (if any) is not regular, a correction operation may be performed, as may be expected in some cases.Such correction may be based on 3D position information of additional optical fibers arranged at the source.

[0150] At step S1170 , a data stream of the projection image and its associated projection direction data is provided for further processing, such as storage, display, etc.

[0151] Preferably, the further processing comprises performing a tomographic reconstruction based on the data stream of projection images and their associated projection direction data.

[0152] At step S1180 , the reconstructed image of the ROI, 3D image volume, or slice in the image domain may then be provided for processing, such as storage or visualization on a display device, as desired.

[0153] As a variation of the above, it may be that the posture change is a posture change of the source relative to a fixed patient. The above is equally applicable and feasible, except that the (one or more) optical fibers are arranged at the source and / or the detector, preferably including an optical fiber connecting the two, and the 3D position information is used to calculate the normal to the plane at the detector and the (X-ray) source, and the projection direction data as the angular deviation between the two normals. Again, if the detector is fixed, the detector normal is a design constant and does not need to be determined and no optical fiber is needed there. The source can be moved manually by a user on a frame mounted on a wheeled or tracked chassis or the like. Motorization is not excluded, but in most embodiments no motorization is required.

[0154] As another variation of the above, in some instances it may be desirable to have the X-ray source remain stationary while detector modules on a similar movable frame (on tracks or wheels) are moved past the patient instead of the X-ray source.

[0155] Therefore, this paper mainly utilizes the mutual motion between the X-ray source and the detector connected by one or more optical fibers to capture the position 3D information, which is then converted into protection direction data α, as described.

[0156] The movement or posture change utilized above may not necessarily be caused by rotational movement of one of the patient, source, or detector. What is important is that projection images are acquired from multiple viewpoints of the ROI from multiple directions. For example, linear movement may be sufficient, although the 3D content may be inferior to images acquired during rotational posture change / movement, and limited angle tomosynthesis may be performed instead of full tomographic reconstruction.

[0157] In addition to the correction step S1160 described above, it is expected that the patient's rotation intervals are irregular and the patient may not be placed in the isocenter (as some tomosynthesis / tomography algorithms may assume). However, since the normal V PThe 3D coordinates of the patient plane are known, so the exact rotation angle can be determined. As described above, the deviation angle between the patient vector VP and the detector normal and / or beam XB / source XS is the projection angle. The latter can be known by using optical fibers at the source as needed. In addition to any rotation about the vertical axis of the patient, the 3D position coordinates of the patient plane and the plane at the source and / or detector can be used to determine whether there is any translation of the patient relative to the source X-ray beam XB. The projection images acquired at step S1140 can be corrected using a correction translation so that the set of projection images is equivalent to the set captured with an isocentric system, albeit with an arbitrary projection angle. This step is optional to improve reconstruction accuracy.

[0158] Instead of compensating for incorrect patient movement at step S1160, the X-ray source can be tilted to maintain alignment with the detector and patient as the X-ray source moves rather than the patient changing their posture. This correction operation can be based on the relative position of V R Deviation / Offset V P , and a prospective correction will be performed by rotating the X-ray source. In this example, when the patient remains stationary, the patient normal V P is a fixed constant that can be easily determined.

[0159] The components of the enabler SYS may be implemented as one or more software modules running on one or more general purpose processing units PU (such as a workstation associated with an imager IA) or on a server computer associated with a group of imagers.

[0160] Alternatively, some or all components of system SYS may be implemented in hardware, such as a suitably programmed microcontroller or microprocessor, such as an FPGA (field programmable gate array), or an application-specific integrated circuit (ASIC) integrated into imaging system 1A as a hardwired IC chip. In another embodiment, system SYS may be implemented partially in software and partially in hardware.

[0161] The different components of the system SYS may be implemented on a single data processing unit PU. Alternatively, some or more components are implemented on different processing units PU that may be arranged remotely in a distributed architecture and connectable in a suitable communication network, such as in a cloud environment or a client-server setup.

[0162] One or more features described herein may be configured or implemented as or with circuits encoded in a computer-readable medium and / or a combination thereof. The circuits may include discrete and / or integrated circuits, systems on a chip (SOCs), and combinations thereof, machines, computer systems, processors and memories, computer programs.

[0163] In a further exemplary embodiment of the present invention, a computer program or a computer program element is provided, which is characterized in that it is adapted to execute the method steps of the method according to one of the preceding embodiments on a suitable system.

[0164] Therefore, the computer program element can be stored on a computer unit, which can also be part of an embodiment of the present invention. The computing unit can be adapted to perform the steps of the method described above or to induce its execution. In addition, it can be adapted to operate components of the above-described apparatus. The computing unit can be adapted to automatically operate and / or execute user commands. The computer program can be loaded into a working memory of a data processor. Therefore, the data processor can be equipped to perform the method of the present invention.

[0165] This exemplary embodiment of the invention covers both a computer program that right from the beginning uses the invention and a computer program that by means of an update turns an existing program into a program that uses the invention.

[0166] Furthermore, the computer program element can provide all necessary steps to implement the procedure of an exemplary embodiment of the method as described above.

[0167] According to a further exemplary embodiment of the present invention, a computer-readable medium, for example a CD-ROM, is proposed, wherein the computer-readable medium has a computer program element stored on the computer-readable medium, the computer program element being described in the preceding section.

[0168] The computer program may be stored and / or distributed on suitable media (particularly, but not necessarily, non-transitory media), such as optical storage media or solid-state media provided with or as part of other hardware, but the computer program may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems.

[0169] However, the computer program may also be present on a network such as the World Wide Web and can be downloaded from such a network into the working memory of a data processor. According to a further exemplary embodiment of the present invention, a medium for making a computer program element available for downloading is provided, which computer program element is arranged to perform a method according to one of the previously described embodiments of the present invention.

[0170] It should be noted that embodiments of the present invention have been described with reference to different subject matters. Specifically, some embodiments are described with reference to method-type claims, while other embodiments are described with reference to apparatus-type claims. However, those skilled in the art will appreciate from the above and following descriptions that, unless otherwise indicated, any combination of features relating to different subject matters, in addition to any combination of features belonging to one type of subject matter, is also considered disclosed by this application. However, all features can be combined to provide synergistic effects that exceed the simple sum of the features.

[0171] Although the present invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description are to be considered illustrative or exemplary rather than restrictive. The present invention is not limited to the disclosed embodiments. Other variations of the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention from a study of the drawings, the disclosure, and the appended claims.

[0172] In the claims, the word "comprising" does not exclude other elements or steps, and the word "a" or "an" does not exclude a plurality. A single processor or other unit may perform the functions of several items recited in the claims. The fact that specific measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope. Such reference signs may consist of numbers, letters, or any alphanumeric combination.

Claims

1. A system (SYS) for facilitating tomographic imaging using a non-rotational radiographic imaging apparatus (IA), comprising: an input interface (IN) for receiving, when the system is in use and there is relative motion between a patient to be imaged (PAT) and a detector (DM) or an X-ray source (XS) of the imaging device: i) 3D position measurement readings acquired by a fiber-optic based system (OFS) via a set of fiber-optic based sensors (Si), the set of fiber-optic based sensors being arranged at i.1) the patient (PAT) or i.2) the detector (DM) and / or source (XS), wherein the measurement readings are capable of being correlated with a posture that the patient can adopt during motion relative to the detector or a posture of the source (XS) or the detector (DM) relative to the patient; and ii) projected images (λ) of the patient acquired by the imaging device during, before and after such relative motion; a projection direction determiner (PDD) configured to determine projection direction data (α) for the projected image (λ) based on the 3D position measurement reading (P), and An output interface (OUT) is configured to provide the projection image associated with the projection direction data for reconstruction.

2. The system according to claim 1, comprising a reconstructor (RECON) configured to implement a tomographic reconstruction algorithm to reconstruct a tomographic image of the patient's region of interest based on the projection images and the projection direction data associated with the projection images.

3. A system according to any one of the preceding claims, wherein The set of fiber-optic based sensors (Si) is at least partially integrated in a wearable (WB) worn by the patient during imaging.

4. A system according to any one of the preceding claims, wherein The relative patient motion is induced by the patient himself, or by a rotating actuator (RF) on which the patient resides during imaging, or by at least the X-ray source (XS) or the detector (DM) in the imaging device being moved past the patient.

5. The system according to claim 4, wherein: The X-ray source is tiltable to maintain alignment with the detector as the X-ray source is moved past the patient.

6. The system according to claim 4 or 5, wherein: The rotation facilitator (RF) includes any one of the following: a swivel stool, a patient bed.

7. A system according to any one of the preceding claims, wherein The projection direction data is determined based on a patient posture normal vector (VP) relative to a normal vector (VR) of a surface of the detector or a normal vector at the source (XS).

8. A system according to any one of the preceding claims, wherein The optical fiber based system (OFS) comprises a second set of sensors (Sj) arranged at the detector.

9. A system according to any one of the preceding claims, wherein The optical fiber based system (OFS) comprises a second set of sensors or a third set of sensors (Sk) arranged at an X-ray source of the imaging device.

10. A system according to any one of the preceding claims, wherein The imaging apparatus (IA) is of mobile type, the X-ray source (XS) of the imaging apparatus being arranged on a wheeled or tracked frame (FR), wherein the imaging apparatus including the X-ray source of the imaging apparatus can be moved past the patient on the frame of the imaging apparatus during imaging.

11. An imaging arrangement (IAR) comprising an imaging arrangement (IA), wherein the imaging arrangement further comprises i) at least one set of fiber-based sensors at a detector and / or at an X-ray source, the at least one set of fiber-based sensors being adapted for use with a system according to any one of the preceding claims; and / or ii) the imaging arrangement further comprises at least one set of fiber-based (F1) sensors (S1) at a patient (PAT); and / or iii) the imaging arrangement comprises an fiber-based system (OFS).

12. The imaging arrangement of claim 11, further comprising a system according to any one of the preceding claims.

13. A computer-implemented method for facilitating tomographic imaging using a non-rotational radiographic imaging device, comprising: receiving (S1110) the following when the system is in use and when there is relative motion between a patient to be imaged (PAT) and a detector (DM) or an X-ray source (XS) of the imaging apparatus: i) 3D position measurement readings acquired by a fiber-optic based system (OFS) via a set of fiber-optic based sensors (Si), the set of fiber-optic based sensors being arranged at i.1) the patient (PAT) or i.2) the detector (DM) and / or source (XS), wherein the measurement readings are capable of being correlated with a posture that the patient can adopt during motion relative to the detector or a posture of the source (XS) or the detector (DM) relative to the patient; and ii) projected images (λ) of the patient acquired by the imaging apparatus during, before and after such relative motion; determining (S1130) projection direction data (α) for the projected image (λ) based on the 3D position measurement reading (P), and The projection image associated with the projection direction data is provided (S1170) for reconstruction.

14. A computer program element which, when run by at least one processing unit, is adapted to cause the processing unit to perform the method according to claim 13.

15. At least one computer-readable medium having a program element according to claim 14 stored thereon.

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