Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
  • A61B6/58—Testing, adjusting or calibrating thereof
  • A61B6/587—Alignment of source unit to detector unit
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B19/00—Programme-control systems
  • G05B19/02—Programme-control systems electric
  • G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
  • G05B19/402—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by control arrangements for positioning, e.g. centring a tool relative to a hole in the workpiece, additional detection means to correct position
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B2219/00—Program-control systems
  • G05B2219/30—Nc systems
  • G05B2219/45—Nc applications
  • G05B2219/45169—Medical, rontgen, x ray

Definitions

• the invention relates to a radiology assembly and more specifically the alignment of two elements of the radiology assembly, namely the plane sensor with respect to the X-ray beam generator tube.
• the invention also relates to a method alignment of such a radiology set.
• the invention lies in the field of radiology (for example medical or veterinary) but is not limited to this field.
• the invention finds potential application in the fields of security and industrial control.
• the invention can also be applied to other fields where it is necessary to align a point source of radiation with a flat sensor, for example in the field of infrared imaging.
• the invention is presented in a case of application to a radiology set. Nevertheless, the invention can find application in other fields requiring good positioning of two elements relative to each other.
• a radiology set consists of two elements: a tube generating an X-ray beam and a flat radiographic image sensor.
• the set is intended mainly for taking X-ray images of patients in a hospital environment.
• a patient, for whom an X-ray is to be taken, is placed between the tube generating an X-ray beam and the plane sensor.
• the two elements must therefore be well positioned relative to each other, so that all the X-rays emitted by the tube generating the X-ray beam are captured by the flat panel detector.
• the alignment must be done before the X-rays are emitted by the tube generating the X-ray beam.
• the goal is to avoid over-irradiating the patient with X-rays arriving outside the sensor while having a good picture quality.
• the X-ray beam generator tube is aligned manually by an operator in front of the plane sensor.
• the alignment is done in translation and in rotation.
• the alignment is generally done when the patient is in place, that is to say positioned between the tube generating the X-ray beam and the flat sensor.
• the flat sensor is hidden. We can cite for example the case where the flat sensor is placed under a patient for an X-ray of the abdomen or the pelvis. We can also cite the case where the flat sensor is placed under a sheet, under a stretcher or even in an incubator. It is therefore, in this case, very difficult for the operator to align the tube generating the X-ray beam with respect to the plane sensor.
• the environment of the plane sensor can be of several types.
• the environment may in particular be a hospital bed or a stretcher with metal frames or an incubator for premature babies.
• the environment of the collector can therefore constitute an additional hindrance for the correct positioning of the generator tube in relation to the flat collector.
• the alignment of the first element with respect to the second element comprises a correction of several defects: centering defect (the X-ray beam is not centered on the flat sensor), orientation defect (the X-ray beam X is badly oriented with respect to the plane of the flat sensor) and lack of perpendicularity (the X-ray beam does not arrive perpendicularly on the flat sensor).
• centering defect the X-ray beam is not centered on the flat sensor
• orientation defect the X-ray beam X is badly oriented with respect to the plane of the flat sensor
• lack of perpendicularity the X-ray beam does not arrive perpendicularly on the flat sensor.
• the lack of squareness is critical when an anti-scatter grid is used to produce the image. The grid is then placed on the flat collector. The X-rays, to be able to be detected by the flat sensor, must arrive on the sensor perpendicular to the flat sensor. The angular tolerance with respect to perpendicularity is small (only a few degrees).
• the alignment can also be done by means of acoustic wave beams.
• the patient can mask all or part of the flat sensor.
• the presence of the patient can locally attenuate the acoustic waves and thus distort the distance measurement between the flat panel detector and the X-ray beam generator tube.
• US patent 10080542 describes a method of providing information for aligning an X-ray beam generator tube and a detector of a mobile X-ray apparatus from orientation sensors of a position absolute value of the X-ray beam generator tube and the detector.
• a single magnetic field is generated at the level of the X-ray beam generator tube along an axis passing through the X-ray beam generator tube and the detector in order to be evaluated, using sensors, at the level of the detector.
• the relative orientation information in rotation is calculated by difference between the absolute orientations of the X-ray beam generator tube and the detector.
• the relative positioning in translation is done by comparing the values of the measured components of the magnetic field with those prerecorded.
• a dental radiology system uses several electromagnetic field emitters placed in the same plane and a or two electromagnetic field receivers able to receive the electromagnetic fields emitted by the transmitters.
• the use of two receivers makes it possible to determine the angular orientation of the sensor but does not give any precision on the angle of one element with respect to the other (generator tube with respect to the plane sensor).
• the positioning of the emitters in the same plane gives mediocre precision on the location of the plane sensor with respect to the generator tube.
• dental radiology covers a relatively short distance between the generator tube and the sensor (20 to 30 cm) compared to the distance between the generator tube and the sensor in the field of medical radiology (rather of the order 1 to 2 m).
• the invention aims to overcome all or part of the problems mentioned above by proposing a radiology assembly with several electromagnetic field transmitters, integral with the tube generating the X-ray beam, which are positioned in separate planes and several sensors of electromagnetic fields positioned on the plane sensor receiving the X-rays.
• This assembly makes it possible to know without ambiguity the position of the plane sensor in space and therefore to know its position relative to the tube generating the X-ray beam, and so to align and position the generator tube with respect to the flat collector.
• the invention is based on a perpendicular alignment of the plane sensor with respect to the tube generating the X-ray beam and then a centering around the main direction of emission of the X-rays.
• the invention relates to a radiology assembly comprising:
• a flat sensor extending along a plane defined by a first direction and by a second direction, substantially perpendicular to the main direction of X-ray emission, intended to receive the X-rays, characterized in that it comprises:
• a first emitter interrupted in two electromagnetic field emitter parts arranged so as to emit a first electromagnetic field in a main direction substantially perpendicular to the main direction of emission, each of the two emitter parts of the interrupted emitter being positioned on either side of the X-ray beam
• a second emitter interrupted in two electromagnetic field emitter parts arranged so as to emit a second electromagnetic field in a main direction substantially perpendicular to the main direction of emission and secant to the main direction of the first electromagnetic field, each of the two parts of the interrupted emitter being positioned on either side of the X-ray beam
• the so-called plane emitter being a coil composed of turns, the said plane emitter being arranged so as to emit a third electromagnetic field in a main direction substantially parallel to the main direction of emission of the beam of X-rays, the turns being crossed by the main direction of emission,
• electromagnetic field sensors integral with the plane sensor, capable of detecting the first, second and third electromagnetic fields emitted alternately in their main direction by the first transmitter, the second transmitter and the so-called plane transmitter and generating a first, second, third electrical signal according to the electromagnetic fields detected,
• - a means for processing the first, second and third electrical signals intended to determine an alignment angle between the main direction of emission and a normal of the plane sensor, to determine a first centering error between the main direction of emission of the first electromagnetic field and the first direction of the flat sensor, in determining a second centering error between the main direction of emission of the second electromagnetic field and the second direction of the flat sensor.
• - a means for correcting the angle of alignment by applying a first corrective movement to the generator tube and the first and second centering errors by applying the first corrective movement and/or a second corrective movement to the tube generator.
• the processing means comprises means for distinguishing the electrical signals generated.
• the means for processing the first, second and third electrical signals comprises an estimator of an orientation angle between the main direction of the first electromagnetic field and the first direction of the flat sensor.
• each of the two emitter parts of the first and second interrupted emitter comprises at least one turn and the main direction of emission of the X-ray beam is positioned between the at least one turn of the first and second transmitter interrupted.
• the so-called flat emitter comprises at least one turn through which the main direction of emission of the X-ray beam passes.
• the two emitter parts of the first and second interrupted emitter and the so-called flat emitter are flat coils.
• the first corrective movement is a rotation of the generator tube in one of the main directions and/or a rotation of the generator tube in the main emission direction and in which the second corrective movement is a translation of the generator tube along one of the main directions.
• the flat sensor comprises at least one inclinometer.
• the processing means and the correction means are mechanically linked to the plane sensor.
• the processing means and the correction means are mechanically linked to the generator tube.
• the method first comprises a calibration step intended to calibrate the electrical signal according to predetermined positions of the generator tube and of the plane sensor.
• the emission by the transmitters of the electromagnetic fields comprises a step of powering the transmitters, and in that the powering of the transmitters takes place at different times or simultaneously at different frequencies. or simultaneously in phase shift so as to differentiate the electromagnetic fields emitted.
• the method comprises a step of evaluating the angle of orientation between the main direction of the first electromagnetic field and the first direction of the flat sensor following the step of correcting of the centering error and comprising a step of correcting the angle orientation between the main direction of the first electromagnetic field and the first direction of the flat sensor following the step of evaluating the angle of orientation.
• figure 1 represents an embodiment of a radiology assembly according to the invention
• figure 2 represents an example of arrangement of the electromagnetic field emitters according to the invention
• Figure 3 shows an example of a support for electromagnetic field emitters
• Figure 4 shows a sectional view of a radiology assembly according to the invention
• FIG. 5 schematically represents the steps of an alignment method according to the invention.
• FIG. 1 shows an embodiment of a radiology assembly 10 according to the invention.
• the radiology assembly 10 comprises a tube 11 generating an X-ray beam 12 centered around a main direction 13 of emission.
• the radiology assembly 10 comprises a plane sensor 14, extending along a plane, defined by a first direction D1 and by a second direction D2, substantially perpendicular to the main direction 13 of emission.
• the plane sensor 14 is intended to receive the X-rays 12.
• the radiology assembly comprises a first transmitter 15 interrupted in two parts of the transmitter 20, 21 of the electromagnetic field arranged so as to emit a first electromagnetic field along a main direction 18 substantially perpendicular to the main direction 13 of emission, each of the two emitter parts 20, 21 of the interrupted emitter 15 being positioned on either side of the X-ray beam 12.
• the interrupted transmitter 15 is secured to the generator tube 11 of the X-ray beam 12. In this configuration, the position of the tube 11 generating the X-ray beam 12 can be deduced from the main direction of the electromagnetic field emitted by the interrupted emitter 15.
• the radiology assembly may comprise a second interrupted transmitter 16 in two electromagnetic field transmitter parts 22, 23, arranged so as to emit a second electromagnetic field in a main direction substantially perpendicular to the main direction 13 of emission and secant to the main direction of the first electromagnetic field, each of the two emitter parts 22, 23 of the interrupted emitter 16 being positioned on either side of the X-ray beam 12.
• each interrupted emitter (for example 15) can be considered to be a pair of emitters 20, 21 whose main faces are parallel to each other, each of the emitters being located on either side of the beam of x-rays 12.
• the pair of emitters 20, 21 (likewise for 22, 23) is equivalent to a virtual emitter which would be located between the two emitters 20, 21, in the beam of x-rays 12.
• the electromagnetic field emitted is equivalent to the electromagnetic field which would be emitted by the equivalent virtual emitter.
• This arrangement has the advantage of not obscuring the X-rays since the pair of emitters are located on either side of the X-ray beam 12 and not in their beam.
• this layout of the transmitters has the advantage of not damaging the transmitters. Indeed, an equivalent emitter placed in the X-ray beam would be damaged by the X-rays during its use. In the case of our invention, the emitters are not subjected to X-radiation and are therefore preserved from the point of view of the resistance of the materials.
• the radiology assembly 10 may further comprise a so-called planar electromagnetic field transmitter 24 arranged so as to emit a third electromagnetic field in a main direction 9 substantially parallel to the main direction 13 of emission.
• the so-called planar emitter 24 makes it possible to have an electromagnetic field parallel to the main direction 13 of emission.
• the arrangement of the transmitters as shown in Figure 1 allows to have electromagnetic fields whose main directions are according to three different axes perpendicular to each other. Since the transmitters are integral with the generator tube 11 of the X-ray beam 12, the electromagnetic fields along the three axes make it possible to determine certain angular information making it possible to compare the different positions of the generator tube 11 and of the plane sensor 14. It can be noted that the three axes are not necessarily perpendicular to each other.
• the directions 18 and 19 can be secant and form any angle (between them and with the main direction 13 of emission).
• the relative position of generator tube 11 with respect to plane sensor 14 can also be determined.
• the frequency of the first, second and third electromagnetic fields is subject to two constraints:
• the frequency of the first, second and third electromagnetic field can be a frequency between 100 Hz and 10 kHz.
• first, second and third electromagnetic fields are emitted successively and according to fixed and different orientations so as to avoid obtaining a rotating field and to avoid any interaction between the first, second and third electromagnetic fields.
• the three directions, preferably perpendicular, are addressed successively and independently with a field of fixed frequency, orientation and amplitude for a defined duration.
• the radiology assembly 10 comprises four sensors 29, 30, 31, 32 of the electromagnetic field.
• the four sensors 29, 30, 31, 32 can be integrated into the plane sensor 14.
• the sensors 29, 30, 31, 32 are intended to detect the electromagnetic fields emitted by the interrupted transmitters 15 and 16 and by the so-called plane transmitter. 24 and generate an electric signal according to the fields electromagnetic detected.
• the radiology assembly may comprise less than four or more than four electromagnetic field sensors.
• the sensors 29, 30, 31, 32 are integrated into the plane sensor 14. They are installed so that they do not disturb the acquisition of the radiological image. They are for example placed at the rear of the radiological image detection elements with respect to the X-ray entry face. the relative position of the generator tube 11 with respect to the plane sensor 14 is necessary. If, on the other hand, they have perfectly symmetrical positions with respect to the center of the plane sensor, perfect centering with respect to the generator tube 11 of the X-ray beam 12 is obtained when the sensors 29, 30, 21, 32 have a signal perfectly balance.
• the radiology assembly 10 comprises means 17 for processing the first, second, third electrical signal. Furthermore, the processing means 17 comprises a computer able to determine an alignment angle between the main direction 13 of emission and a normal N1 of the plane sensor 14. The processing means 17 also comprises a computer able and to determine a first centering error between the main direction 18 of emission of the first electromagnetic field and the first direction D1 of the plane sensor 14 and a second centering error between the main direction 19 of the second electromagnetic field and the second direction D2 of the plane sensor 14.
• the particularity of the radiology assembly according to the invention resides in its mode of alignment.
• the invention performs an alignment between the normal N1 of the flat sensor and the main direction 13 of emission of the X-rays, then a centering of the plane sensor around the normal N1, then merged with the main direction 13 of X-ray emission.
• the processing means 17 also includes an estimator of an orientation angle between the main direction 18 of the first electromagnetic field and the first direction D1 of the plane sensor 14. Furthermore, in order to ensure the robustness of the radiology assembly 10, the processing means 17 comprises means for distinguishing the electrical signals generated. Indeed, each electrical signal generated inducing a correction, it is necessary to clearly target which electrical signal is picked up at the level of the sensors 29, 30, 31, 32 of the plane sensor 14.
• the radiology assembly 10 also includes means 171 for correcting the alignment angle and the first and second centering errors. More specifically, upon receipt of the alignment angle and the first and second centering errors from the processing means 17, the correction means 171 acts, in the case of a correction of the alignment angle , via a first corrective movement on the generator tube 11 and acts, for the case of a correction of the first and/or second centering error, via the first corrective movement and/or a second corrective movement on the generator tube 11 .
• the first corrective movement is a rotation of the generator tube 11 in one of the main directions 18 and 19 of the first and second electromagnetic field or a rotation of the generator tube 11 in the main direction 13 of emission.
• the second corrective movement is a translation of the generator tube 11 along one of the main directions 18 and 19 of the first and second electromagnetic field. Both the first corrective movement and the second corrective movement can be done manually or be automated in connection with the correction means 171 .
• the correction means 171 is capable of correcting the angle of orientation between the main direction 18 of the first electromagnetic field and the first direction D1 of the plane sensor 14 by applying the first corrective movement to the generator tube 11 .
• the evaluation and correction of the orientation angle remains optional vis-à-vis the evaluation and correction of the alignment angle and the centering error.
• the orientation angle is then necessarily close to zero degrees. This orientation angle is therefore a measurement making it possible to confirm the correct alignment and the correct centering of the generating tube 11 of an X-ray beam 12 and of the flat sensor 14.
• processing means 17 and the correction means 171 are, in a preferred embodiment, mechanically linked to the plane sensor 14. Nevertheless, the processing means 17 and the correction means 171 can also be mechanically linked. to the generator tube 11 .
• the typical working distance is large enough for the magnetic field measured at the level of the receiver (i.e. the plane sensor 14 in our case) to be considered as coming from a magnetic dipole of moment M.
• p0 is a fundamental constant, called vacuum magnetic permeability
• r is the distance between the emitting source and the point M and 0 is the alignment angle in the vicinity of the alignment.
• the first interaction is described in that a translation along the main direction 18 of the first electromagnetic field between the detector (the plane sensor 14) and the emitting source (the generator tube 11) along the main direction 18 of the first electromagnetic field involves a rotation of the field measured at the level of the detector (the plane sensor 14) similar and opposite to the application of a rotation along the main direction 19 of the second electromagnetic field between the detector (the plane sensor 14) and the emitting source (the generator tube 11 ).
• the interaction is resolved by using an inclinometer at the level of the detector (the plane sensor 14) to evaluate the alignment with respect to the emitting source (the generator tube 11). Knowing the alignment angle makes it possible to apply a relative rotation between the detector (the plane sensor 14) and the emitting source (the generator tube 11) in order to obtain an alignment between the plane sensor 14 and the generator tube 11 .
• the angle measured at the level of the fields comes only from the displacements respectively linked to the first centering error along the main direction 18 and to the second centering error along the main direction 19.
• the distance, along the main direction 13 of emission, of positioning of the detector (the plane sensor 14) vis-à-vis the emitting source (the generator tube 11) when the two are aligned is not a quantity to be fixed at a precise value. This distance must simply be between a minimum value and a maximum value which are characteristic of the anti-scattering grid. This value can however be estimated by measuring the module of the electromagnetic field at the center of the detector (plane sensor 14) by averaging the values measured on the sensors 29, 30, 31, 32 and by correlating it with a calibration of the module of the induction as a function of the distance between the detector (the plane sensor 14) and the emitting source (the generator tube 11).
• FIG. 2 represents an example of arrangement of the emitters 15 and 16 of the electromagnetic field according to the invention.
• the radiology assembly comprises two interrupted emitters 15, 16 in two parts of emitters 20, 21 and 22, 23 of electromagnetic field.
• the first transmitter 15 interrupted in two parts of the electromagnetic field transmitter 20, 21 is arranged so as to emit a first electromagnetic field in a main direction 18 substantially perpendicular to the main direction 13 of emission.
• Each of the two emitter parts 20, 21 of the interrupted emitter 15 is positioned on either side of the X-ray beam 12.
• the second interrupted emitter 16 in two emitter parts 22, 23 of field electromagnetic is arranged to emit a second electromagnetic field in a main direction 19 substantially perpendicular to the main direction 13 of emission and substantially perpendicular to the main direction 18 of the first electromagnetic field.
• Each of the two emitter parts 22, 23 of the interrupted emitter 16 is positioned on either side of the X-ray beam 12.
• the interrupted emitters 15 and 16 and the so-called plane emitter 24 can be, for example, coils or solenoids. More specifically, each of the two emitter parts 20, 21 of the interrupted emitter 15 and each of the two emitter parts 22, 23 of the interrupted emitter 16 comprises at least one turn in which a current can flow. And, in this way, the so-called plane 24 emitter comprises at least one turn in which a current can flow.
• a surface 120 of the emitter part 20 is substantially parallel to a surface 121 of the emitter part 21.
• the electromagnetic field emitted by the interrupted emitter 15 has a main direction 18 perpendicular to the surfaces 120 and 121.
• a surface 122 of the emitter part 22 is substantially parallel to a surface 123 of the part of emitters 23.
• the electromagnetic field emitted by the interrupted emitter 16 has a main direction 19 perpendicular to the surfaces 122 and 123.
• the surfaces 120 and 121 are perpendicular to the surfaces 122 and 123.
• the main directions 18 and 19 are then substantially perpendicular to each other.
• This arrangement is particularly advantageous if the generator tube 11 of the X-ray beam 12 has a square-shaped emission flux.
• the flow of X-rays 12 is emitted along the main direction 13 of emission, between the surfaces 120, 121, 122, 123, without intersecting the emitters 15, 16 (and therefore without damaging them), without being obscured since the emitters 15, 16 are not located in the X-ray flux 12.
• This configuration of the interrupted emitters 15 and 16 makes it possible to observe that the main direction 13 of emission of the X-ray beam 12 is positioned between the at least one turn of the interrupted emitter 15 and of the interrupted emitter 16 and makes it possible to ensure that each of the pairs of emitters 20, 21 and 22, 23, whose respective surfaces 120, 121 and 122, 123 are parallel to each other, is equivalent to a virtual emitter located at the center of the surfaces 120, 121, 122, 123 of the emitters 15, 16, at the level of the main direction 13 of X-ray emission, whereas it would be impossible to place a single emitter in the center since the center is occupied by the X-ray beam.
• the transmitters can emit, in an off-centered position, an electromagnetic field equivalent to an electromagnetic field emitted in a centered position, without obscuring the X-rays emitted by the generator tube 11 .
• the at least one turn of the interrupted emitters 15 and 16 as well as of the so-called planar emitter 24 can be of square shape or of rectangular shape or else of circular shape.
• a surface represented by the turn of the emitter called plane 24 can be interpreted as the surface 124 of the emitter called plane 24.
• This surface 124 of the emitter called plane 24 is substantially perpendicular to the surfaces 120, 121, 122, 123.
• the flow of X-rays 12 can pass through the so-called plane emitter 24 at the level of the turn. The flow of X-rays 12 is not obscured by the so-called plane emitter 24 because it passes through it through the turn(s).
• the arrangement of the transmitters as shown in Figure 2 allows to have electromagnetic fields whose main directions are along three different axes perpendicular to each other.
• the interrupted transmitters 15 and 16 as well as the so-called plane transmitter 24 being integral with the generator tube 11 of the beam of X-rays 12, the electromagnetic fields along the three axes make it possible to determine certain angular information such as the alignment angle, the first and second centering errors or even the angle of orientation of the tube generator 11 of the X-ray beam 12 with respect to flat collector 14.
• the three axes are not necessarily mutually perpendicular.
• the directions 18 and 19 can be secant and form any angle (between them and with the main direction 13 of emission). More broadly, the electromagnetic fields along the three axes make it possible to determine the position of the generator tube 11 of the X-ray beam 12 with respect to the plane sensor 14.
• the transmitters are three in number (15, 16, 24, i.e. 4 parts of transmitters 20, 21, 22, 23 and one transmitter 24) and positioned so as to form a rectangular parallelepiped. Nevertheless, it is quite possible to have more than three emitters, each one being positioned on a face of a polyhedron whose number of faces would correspond to the number of parts of emitters and emitters used. A greater number of emitters adds to the precision of the evaluation of the angle of alignment, of the first and second centering errors and, optionally, of the angle of orientation of the generator tube 11 with respect to the plane sensor 14. Nevertheless, this greater number generates higher production costs and greater signal processing complexity. Three transmitters as in figure 2 represent a very good compromise between precision of the evaluation of angular information and complexity of signal processing.
• Figure 3 shows an example of a support 39 of the electromagnetic field emitters.
• the support 39 has faces 40, 41, 42, 43, 44 substantially perpendicular to each other.
• the face 42 has a groove 45 able to receive the transmitter part 22.
• the face 44 has a groove 46 able to receive the transmitter 24. It is the same for each of the faces.
• the support 39 comprises an intermediate element 47, substantially perpendicular to the faces 40, 41, 42, 43 and substantially parallel to the face 44.
• the intermediate element 47 is a fixing means making it possible to secure the support 39 (and therefore the transmitters 15, 16, 24) of the generator tube 11 of the X-ray beam 12.
• the support 39 then has another three-dimensional geometric shape having flat faces, each having a groove arranged to accommodate an emitter.
• the transmitters are made on a printed circuit board.
• flat coils can be fixed on the faces of a collimator, acting as a rigid and movable framing structure of the generator tube 11 of the X-ray beam 12.
• the two emitter parts 20, 21 and 22 , 23 of the first and second interrupted transmitter 15 and 16 and the so-called plane transmitter 24 are flat coils, thus reducing the overall size of the system.
• the flat coils replace the faces of the collimator or be directly integrated into the collimator.
• the surfaces two by two parallel to each other (120 and 121, 122 and 123) and the placement of the transmitters in the grooves provided for this purpose mean that the left and right turns (Faces 42 and 43) and / or front and rear (faces 40 and 41) very symmetrical allow to have a magnetic field perfectly centered on the center of the geometric shape without hindering the passage of X-rays. It is not necessary to have several windings in the grooves at the level of the side faces, the lower winding, that is to say that at the level of the face 44 in the groove 46 being sufficient for symmetry.
• each interrupted emitter (15, 16) is interrupted into two electromagnetic field emitter parts (20, 21; 22, 23) configured to generate an electromagnetic field perfectly centered between the two faces that the parts of issuer constitute.
• the two emitter parts each have a surface, their two surfaces are parallel to each other.
• FIG. 4 shows a sectional view of the radiology assembly 10 according to the invention.
• the sensors 29, 30, 31, 32 are integrated into the plane sensor 14. They are installed so that they do not disturb the acquisition of the radiological image. They are for example placed at the rear of the radiological image detection elements with respect to the X-ray entry face.
• the electromagnetic field sensors 29, 30, 31, 32 can be, for example, coils, magnetometers, magnetoresistors, anisotropic magnetoresistors, magneto-transistors, magneto-diodes, flux gates or effect sensors.
• the plane sensor 14, as well as the generator tube 11 of the X-ray beam 12 can comprise at least one inclinometer.
• inclinometers placed at the level of the generator tube 11 and at the level of the plane sensor 14 make it possible to evaluate the acceleration of gravity on the emission part, that is to say at the level of the generator tube 11, and on the reception part, at the level of the plane sensor 14.
• This acceleration which gives an absolute vector and, normally, identical for the transmission and reception parts must then be projected in a different way according to the observable deviation from the alignment, the centering and the orientation of the generator tube 11 with respect to the flat sensor 14.
• the absolute vector of the generator tube 11 is collinear with the absolute vector of the flat sensor 14.
• the angle formed between the absolute vector of the generator tube 11 and the absolute vector of the plane sensor 14 corresponds to an inclination between the plane formed by the main directions 15 and 16 of the generator tube 11 and the plane formed by the first direction D1 and by the second direction D2 of the flat sensor 14 and therefore to a misalignment between the generator tube 11 and the flat sensor 14.
• Each of the electromagnetic field sensors 29, 30, 31, 32 may comprise an electronic amplification and filter circuit (not shown in the figure) intended to process the electrical signal generated by each of the sensors 29, 30, 31 , 32.
• Each sensor 29, 30, 31, 32 detects an electromagnetic field and generates an electric signal depending on the amplitude of the detected electromagnetic field. The electrical signal generated is processed by the electronic amplification and filter circuit.
• each sensor 29, 30, 31, 32 can generate one or more pieces of information. If the sensor is single-axis, it generates a single piece of information. If the sensor is multi-axis, it generates several information. The use of multi-axis sensors makes it possible to know the amplitude of the electromagnetic field as well as its orientation.
• the sensors are single-axis sensors, twelve pieces of information are available for a given position of the plane sensor 14. If the sensors are tri-axis sensors, then thirty-six items of information are available.
• the detected signals are digitized and transmitted to the computer of the processing means 17, represented in FIG. 1, which processes the angular information such as the angle of inclination, the first and second centering error or even the angle of orientation of the flat sensor 14 with respect to the generator tube 11 of the X-ray beam 12.
• the information from the sensors 29, 30, 31, 32 is then transmitted in digital form. They can thus pass either by wired link or by wireless link.
• FIG. 5 schematically represents the steps of an alignment method according to the invention.
• the method for aligning a radiology assembly 10 according to the invention comprises the following steps:
• step 102 Emission by the so-called plane transmitter of a third electromagnetic field (step 102) in a main direction 9 substantially parallel to the main direction 13 of emission,
• step 130 Evaluation of the alignment angle (step 130) between the main direction 13 of emission and a normal of the plane sensor 14,
• step 131 Fixed alignment angle (step 131 ) between main direction 13 transmission and a normal N1 of the plane sensor 14 by application of the first corrective movement
• step 141 Correction of the first and of the second centering error (step 141 ) by applying the first corrective movement and/or the second corrective movement.
• the processing means 17 must include means for distinguishing the electrical signals generated according to the first, second and third electromagnetic field detected.
• the step 130 of evaluating the angle of alignment between the main direction 13 of emission and the normal of the plane sensor 14 is done by means of a processing of the first, second and third electrical signals at the using, for example, the electronic amplification and filtering circuit mentioned above.
• the alignment angle is evaluated and analyzed in order to better know the difference in alignment between the generator tube 11 and the plane sensor 14.
• the angle of alignment makes it possible to highlight a parallelism between the plane formed by the main directions 18 and 19 of the first and second electromagnetic fields at the level of the generator tube 11 and the plane formed by the first and the second direction D1 and D2 of the plane sensor 14.
• step 131 of correcting the angle of alignment makes it possible to obtain parallelism between the plane of the generator tube 11 perpendicular to the X-ray beam 13 and the plane of the plane sensor 14 stated above.
• the first corrective movement is applied so as to obtain a rotation according to one of the main directions 18, 19 of the first or second electromagnetic field. In this way, it is ensured to have the X-ray beam 12 well aligned in front of the flat sensor 14 and to avoid irradiating outside the flat sensor 14.
• the step 140 of evaluating the first centering error between the main direction 18 of emission of the first electromagnetic field and the first direction D1 of the plane sensor 14 and the second centering error between the main direction 19 of emission of the second electromagnetic field in the second direction D2 of the plane sensor 14 takes place by means of a processing of the first, second and third electrical signals using, for example, the electronic amplification circuit and filtering mentioned above.
• the evaluation and analysis of the first and second centering error makes it possible to highlight a potential lack of centering between the generator tube 11 and the flat sensor 14. This then results in irradiation of the X-ray beam 12 outside of the zone of the plane sensor 14, which is not optimal.
• the step 141 of correcting the first centering error and the second centering error then makes it possible to reframe the generator tube 11 with respect to the plane sensor 14.
• the generator tube 11 undergoes a rotation along the main direction 13 of emission until the main direction 18 of the first electromagnetic field of the generator tube 11 is parallel to the first direction D1 of the plane sensor 14 and until the main direction 19 of the second field electromagnetic is parallel to the second direction D2 of the plane sensor 14 by application of the first corrective movement.
• the plane formed by the main directions 18 and 19 of the first and second electromagnetic fields at the level of the generator tube 11 and the plane formed by the first and the second direction D1 and D2 of the plane sensor 14 are then collinear.
• the generator tube 11 undergoes a translation along the main direction 18 of the first electromagnetic field and/or along the main direction 19 of the second electromagnetic field by the application of the second corrective movement until the projection of the main direction 18 of the first electromagnetic field and of the main direction 19 of the second electromagnetic field on the plane formed by the first direction D1 and the second direction D2 of the plane sensor 14 are respectively the first direction D1 and the second direction D2 of the plane sensor 14 .
• the generator tube 11 is aligned with the plane sensor 14, which optimizes the irradiation.
• the alignment method according to the invention may include a calibration step 150 beforehand intended to calibrate the electrical signal according to predetermined positions of the generator tube 11 and of the plane sensor 14. During this step, the angular information mentioned above are recorded and then used to determine corrective terms that will be taken into account during the following steps.
• the alignment method according to the invention may comprise, following step 141, a step of evaluating an orientation angle between the main direction 18 of the first electromagnetic field and the first direction D1 of the plane sensor 14 made by means of a processing of the first, second and third electric signals using, for example, the electronic circuit of amplification and filtering stated previously.
• This step makes it possible to validate the correct parallelism between the main direction 18 of the first electromagnetic field and the first direction D1 of the plane sensor 14. Indeed, although this parallelism is verified during step 141, the evaluation of the angle orientation makes it possible to provide an additional verification, which increases the precision and the robustness of the alignment method according to the invention.
• the processing means 17 of the first, second, third electrical signal of the radiology assembly 10, represented in FIG. 1 can comprise an estimator of the optional orientation angle in addition to the estimation of the alignment angle and the first and second centering error of the generator tube 11 with respect to the plane sensor 14.
• an additional orientation angle correction step can be introduced in order to correct the parallelism between the main direction 18 of the first electromagnetic field and the first direction D1 of the plane sensor 14 by application of the first corrective movement along the main direction 13 of emission.
• this step of evaluating and correcting the orientation angle is optional but increases the robustness and precision of the alignment method.
• the alignment method may comprise a step of validating the alignment of the generator tube 11 and of the plane sensor 14 following step 131 . This alignment validation step makes it possible to judge the correct alignment of the two elements mentioned above. To do this, the alignment angle, corrected during step 131, is compared with a threshold alignment angle, which can be, for example, from 1° to 2°.
• the alignment angle can undergo a new correction of the alignment angle (step 131) between the main direction 13 of emission and the normal N1 of the plane sensor 14 by additional application of the first corrective movement.
• the alignment method can include a step of validating the centering of the generator tube 11 and of the plane sensor 14 following step 141 .
• This centering validation step makes it possible to judge the proper centering of the two elements mentioned above.
• the first centering error and the second centering error, corrected during step 141 are respectively compared with a first centering error threshold and with a second centering error threshold, which can be, for example d 'about 2 centimeters to 5 centimeters.
• the centering validation is not conclusive, that is to say if the first centering error and the second centering error, corrected during step 141 , remain greater than the first error of centering error and the second centering error threshold, then the first centering error and the second centering error can undergo a new correction the first centering error and the second centering error (step 141 by additional application by application of the first movement corrective and/or the second corrective movement.
• the supply of the transmitters 15, 16, 24 by the electrical signals is done at different times or simultaneously at different frequencies or simultaneously in phase shift so as to differentiate the electromagnetic fields emitted.
• the supply of the first interrupted transmitter 15 and the supply of the second interrupted transmitter 16 can be done at different times or simultaneously at a different frequency or in phase shift.
• the fact of supplying the interrupted transmitters at different times or simultaneously at a different frequency or in phase shift is a means of distinguishing the electrical signals generated.
• the supply of the so-called plane transmitter 24 and the supply of the first interrupted transmitter 15 and of the second interrupted transmitter 16 can take place at different times or simultaneously at different frequencies or in phase shift.
• the system can operate inside a building in a disturbed environment
• the invention can be easily implemented by adding an emitter system integral with the X-ray source and its collimator and by adding compact sensors integrated into the electronics of the detector,
• the calculated information can easily be transmitted to the radiological system to perform an automatic alignment of the tube with the detector.
• the main innovation is a method making it possible to simply solve the problem of alignment between a transmitting source and a receiver in an iterative manner without resorting to calculations, estimates and complex algorithms.
• This method is based on:

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• 2020
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