WO2020015920A1 - Appareil à rayons x médical et procédé d'étalonnage d'énergie - Google Patents

Appareil à rayons x médical et procédé d'étalonnage d'énergie Download PDF

Info

Publication number
WO2020015920A1
WO2020015920A1 PCT/EP2019/064778 EP2019064778W WO2020015920A1 WO 2020015920 A1 WO2020015920 A1 WO 2020015920A1 EP 2019064778 W EP2019064778 W EP 2019064778W WO 2020015920 A1 WO2020015920 A1 WO 2020015920A1
Authority
WO
WIPO (PCT)
Prior art keywords
ray
calibration
photons
medical
detector
Prior art date
Application number
PCT/EP2019/064778
Other languages
German (de)
English (en)
Inventor
Thorsten Ergler
Martin Hupfer
Niko Köster
Original Assignee
Siemens Healthcare Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens Healthcare Gmbh filed Critical Siemens Healthcare Gmbh
Publication of WO2020015920A1 publication Critical patent/WO2020015920A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T7/00—Details of radiation-measuring instruments
    • G01T7/005—Details of radiation-measuring instruments calibration techniques

Definitions

  • the invention relates to a medical X-ray device having a first counting X-ray detector, a method for energy calibration of the first counting X-ray detector and a calibration target.
  • x-ray imaging for example in radiography, computer tomography or angiography
  • counting direct-converting x-ray detectors or integrating (in) direct-converting x-ray detectors can be used.
  • X-ray detectors for radiation-based, in particular X-ray-based imaging such as, for example, computer tomography (CT), angiography, radiography or mammography, directly converting detector materials or converter materials compared to scintillator materials, for example Csl, Se or GOS, open up new cli African application areas. They offer the possibility of individually counting X-ray quanta or X-ray photons and measuring them energetically.
  • the X-rays or the photons can be converted into electrical impulses by a suitable converter material in directly converting X-ray detectors.
  • a suitable converter material for example, CdTe, CdZnTe (CZT), CdZnTeSe, CdTeSe, CdMnTe, InP, TlBr2, HgI2, GaAs or others can be used as converter material.
  • the electrical impulses are evaluated by evaluation electronics, for example an integrated circuit (Application Specific Integrated Circuit, ASIC).
  • ASIC Application Specific Integrated Circuit
  • the level of the electrical pulse is usually proportional to the energy of the absorbed X-ray, especially after a preamplifier and a shaper. genphotons. In this way, spectral information can be extracted by comparing the height of the electrical pulse with an energy threshold. By comparison with several reference signals or the underlying energy threshold values, the incident photons are counted in each detector element of the X-ray detector in the corresponding energy range above an energy threshold.
  • These reference signals or these energy threshold values are usually set globally during the method for energy calibration by specifying a single digital value (DAC value) per energy threshold for the entire X-ray detector.
  • Each detector element can have several individually adjustable energy thresholds, each with an energy threshold value.
  • the energy threshold values can be set at least partially the same or at least partially differently for all detector elements, in particular after an energy calibration.
  • the digital value is converted into the reference voltage with a digital-to-analog converter.
  • the reference voltage is transferred to a comparator unit, which carries out the actual comparison of the measurement signal with an energy threshold. Due to production-related variations in the converter material and the detector elements, the global DAC value can correspond to different photon energies during the energy calibration process in each individual detector element.
  • the X-ray detector can thus be energy calibrated, the aim being that all detector elements have the essentially same energy threshold (s) with regard to the photon energy and can have different energy threshold values or reference voltages per energy threshold.
  • Spectral-resolving or directly converting X-ray detectors provide insight into a previously unused area of X-ray information. In order to get the spectroscopic information spatially resolved, this information has to be evaluated in every pixel.
  • the answer of an ideal energy-resolving or counting X-ray detector without taking into account charge-sharing effects to a series of incident monoenergetic X-rays or calibration photons with constant energy depending on the set energy threshold is essentially step-wise, whereby with increasing energy threshold from a certain energy threshold none Photons are counted more.
  • the detector response is essentially the same for all detector elements or pixels and is achieved at the same energy threshold value or DAC value of the energy threshold.
  • the individual detector elements can have an offset between the set DAC value and the resulting energy threshold.
  • the differences between the detector elements can be measured and compensated for using an energy calibration.
  • the energy calibration can at least partially also be referred to as “trimming”.
  • a step-like detector response is expected for each detector element. As long as the set DAC value corresponds to an energy threshold above the pulse height, the pulses are not recorded. If the DAC value corresponds to an energy threshold that is less than or equal to the pulse height, the detector element will essentially count all the pulses that arrive during the given recording time. In a real X-ray detector, this ideal case can generally not be achieved for a number of reasons.
  • a method is known from US Pat. No. 8,585,286 B2, wherein an assignment between the output signal of the detector pixel and a spectral property is included.
  • the method further comprises determining an energy of a photon detected by the detector pixel based on the output signal of the detector pixel and the assignment.
  • a method for energy calibration of quantum-counting x-ray detectors in an x-ray system with at least two x-ray systems rotatable about a center of rotation is known from the publication DE 10 2012 204 350 A1.
  • a target for generating x-ray fluorescence radiation is positioned between the first x-ray source and the first x-ray detector and irradiated with x-ray radiation from the first x-ray source such that x-ray fluorescence radiation is generated by the x-ray radiation from the first x-ray source and strikes the second x-ray detector from the target.
  • the energy calibration of the second X-ray detector is then carried out using the X-ray fluorescence radiation of the target.
  • the energy calibration of the first X-ray detector can be carried out using the X-radiation from the second X-ray source.
  • the X-ray detectors of a dual-source CT X-ray system can be calibrated with little effort under conditions close to the system.
  • a detector is used in which energy thresholds are assigned to the adjustable threshold values of the comparators,
  • each empty measurements are carried out with differently set threshold values of the comparators
  • an adapted threshold value for this energy threshold is determined from the empty measurements, first empty measurements being carried out in each case with the different spectral compositions of the radiation, at which the threshold values of the comparators are set to a value assigned to the energy threshold, and the normalized counting rates are calculated from the first empty measurements and then further empty measurements are carried out in the same way, in which the threshold values of the comparators are varied, until a measure for each of the channels under consideration for a variation of a normalized counting rate of the channel over the different spectral compositions of the radiation is reduced or minimized.
  • the invention is based on the problem that the known methods, in particular from the field of computed tomography, cannot be transferred to systems other than these.
  • the object is achieved by a medical X-ray device according to claim 1, a method for energy calibration according to claim 14 and a calibration target according to claims 15 and 16.
  • the invention relates to a medical X-ray device aufwei send a first X-ray source and a first counting X-ray detector.
  • the first X-ray source emits a beam of X-ray photons.
  • the first counting x-ray detector has a detection area. An angle between the surface normal of the detection surface and a central beam of the beam can be set in such a way that the central beam of the beam runs in a calibration mode that is not normal to the surface of the detection surface.
  • a calibration target can be positioned in such a way that calibration photons are triggered in the calibration target by means of the X-ray photons and the calibration photons strike at least a partial area of the detection area, and the partial area of the detection area is essentially shielded from X-ray photos.
  • the essentially, in particular complete, shielding of the partial area from X-ray photons can mean that essentially only calibration photons are incident on the partial area. Essentially no X-ray photons are incident on the partial area.
  • the first counting x-ray detector has a detection surface.
  • the detection area is (x-ray
  • the detection area usually faces the first or second X-ray source, so that X-ray photons can strike the detection area.
  • the detection surface faces the calibration target in the calibration mode, so that calibration photons can fall on the detection surface.
  • the detection area comprises at least one detector element.
  • the detection area comprises a plurality of detector elements in a matrix-like arrangement.
  • the detector elements can also be referred to as pixels or subpixels, where a plurality of subpixels can form a (macro) pixel.
  • Each detector element can be designed for energy-resolving or counting measurement.
  • An angle between the surface normal of the detection surface and the central beam of the beam or the first X-ray source can be set.
  • an angle not equal to 0 or 180 degrees can be set.
  • the central beam of the beam can thus run in a calibration mode not normal to the surface of the detection area.
  • the surface normal of the detection surface can in particular have an intersection with a surface of the calibration target at which the calibration photons are triggered.
  • the calibration photons can thus advantageously fall onto the detection area or a partial area of the detection area, while the X-ray photons can be simplified and essentially completely shielded at least from the partial area of the detection area.
  • the calibration photons can also be referred to as fluorescence photons.
  • the angle of incidence of the X-ray photons corresponds essentially to the angle of incidence of the calibration photons, which are incident on the partial area of the detection area.
  • the surface normal of the first X-ray detector can hit the calibration target in particular from the angle of reflection.
  • the angle of failure can run almost parallel to the surface normal of the calibration target, the deviation from the surface normal being less than 10 degrees and preferably less than 5 degrees. In each case, increased shielding of the partial region of x-ray photons can advantageously be achieved. An improved signal yield of the calibration photons on the first X-ray detector can advantageously be achieved.
  • the imaging mode is an operating state that is different from the calibration mode.
  • the imaging mode there is usually an examination object between the x-ray detector and the x-ray source, so that an image of the examination object is generated by means of the x-ray radiation.
  • a recording of medical image data of an examination object is available in the imaging mode.
  • Ka Librations ses is no examination object, in particular in the form of a patient, arranged between the X-ray detector and X-ray source.
  • a calibration target with a (fluorescent) material with known fluorescence properties for example iodine, tin, molybdenum or tungsten, is arranged in the medical device instead of the object to be examined.
  • the first X-ray source is moved to the first X-ray detector by an angle, which is in particular freely optimized in order to ensure the most efficient energy calibration possible.
  • the angle of incidence of the X-ray photons on the calibration target can correspond to the angle of reflection of the calibration photons.
  • Those photons triggered by fluorescence can be referred to as calibration photons, which essentially take the direct path from the calibration target to the first x-ray detector and in particular are incident essentially perpendicular to the first x-ray detector.
  • the first x-ray detector of the medical device can directly measure the fluorescence radiation or the calibration photons of the calibration target, which is generated by irradiation of the x-rays from the system's first x-ray source.
  • the angle is advantageously not fixed, but can be optimized for the medical device.
  • the beam of rays emitted by the first x-ray source is preferably superimposed in such a way that only the calibration target is illuminated and the first x-ray detector is not illuminated.
  • the calibration target is placed in such a way that the calibration photons preferably illuminate the essentially entire detection area of the first X-ray detector.
  • the first x-ray source can be moved independently of the first x-ray detector, so that the method according to the invention can be carried out at different angular positions and thus a complete energy calibration of the first x-ray detector can be achieved.
  • the calibration target can be exchanged, the fluorescent material of the first calibration target being different from the fluorescent material of the second calibration target.
  • the fluorescent material of the first calibration target being different from the fluorescent material of the second calibration target.
  • several fluorescent materials can be used in particular. The accuracy of the energy calibration can be increased with the number of fluorescence materials used.
  • the proposed medical X-ray device and the process for this purpose enable the generation and detection of characteristic fluorescent radiation or calibration photons, which can be used for energy calibration.
  • the proposed arrangements of the first x-ray source in conjunction with the first x-ray detector allow the angle to be set and advantageously also take into account the features of dual-plane systems with two x-ray source / x-ray detector pairs, which can be arranged flexibly with respect to one another.
  • the invention advantageously allows the angle between the first x-ray source, calibration target and first x-ray detector to be freely selected.
  • the energy calibration can also be carried out at several different angles and thus the entire first x-ray detector or its detector elements of the entire detection area can be calibrated step by step.
  • the first counting x-ray detector is rotatably mounted about an axis perpendicular to the central beam.
  • a rotatable suspension of the first x-ray detector for example on a C-arm of an angiography or radiography system, an angle can also be set without relative changes in position between the first x-ray source and the first X-ray detector can be adjustable.
  • additional shielding of the X-ray radiation from the first X-ray detector can be dispensed with, since the rear of the first X-ray detector can take on this task by means of an, in particular additional, shielding configuration, for example in the form of a shielding element.
  • the shielding configuration of the rear side of the first x-ray detector can in particular be configured such that the x-ray photons are essentially completely shielded and thus the first x-ray detector is protected or shielded from the incidence of x-ray photons, for example in an evaluation unit or the converter material.
  • a rotation angle of Q> 90 ° can in particular mean that fewer or substantially no X-ray photons can be incident on the detection surface due to the arrangement of the detection surface with respect to the central beam or the first X-ray source.
  • the detection area can face away from the first X-ray source.
  • the angle of rotation can correspond to the angle.
  • the angle of rotation can also be used to optimize the signal strength of the calibration photons or the optimal angle.
  • the first X-ray detector is tilted or rotated by Q ⁇ n / 2, an additional absorber may be required to shield the direct radiation. With a rotation angle of Q> n / 2, the first X-ray detector can advantageously be calibrated without additional shielding.
  • the first x-ray source can be adjusted, in particular rotated or moved, relative to the first counting x-ray detector.
  • the first x-ray source can be designed to be rotatable about the focus or on the suspension of the first x-ray source.
  • the medical X-ray device is designed in such a way that the first X-ray source can be moved around an object to be examined or the win- dow essentially independent of the first X-ray detector. is adjustable.
  • Such a medical x-ray device can be designed as a mammography system which offers a tomosynthesis or an option for biopsy.
  • the angle can be achieved by adjusting the relative position from the first X-ray source to the first X-ray detector.
  • the medical x-ray device can be a system with a robotic radiator holder.
  • the angle can advantageously be flexibly adjustable.
  • the first counting x-ray detector is assigned to the first x-ray source.
  • the medical X-ray device can be a mammography system or a C-arm system, for example with a tiltable first X-ray detector.
  • Energy calibration of the first x-ray detector can advantageously be carried out in a medical x-ray device with only one x-ray source / x-ray detector pair.
  • the first counting x-ray detector is assigned to a second x-ray source and a second x-ray detector is assigned to the first x-ray source.
  • the medical x-ray device can be a dual-plane C-arm system which has two pairs of x-ray sources and x-ray detectors.
  • the first x-ray source-x-ray detector pair comprises the second x-ray source and the first counting x-ray detector.
  • the second x-ray source-x-ray detector pair comprises the first x-ray source and the second counting x-ray detector.
  • the first pair of x-ray sources and x-ray detectors defines a first imaging plane (tarpaulin).
  • the second x-ray source-x-ray detector pair defines a second imaging plane (plane).
  • the two x-ray source-x-ray detector pairs can be positioned essentially independently of one another.
  • the second X-ray detector can be a counting or internal tegrating x-ray detector. Because of the greater freedom in the positioning of the second imaging plane compared to, for example, a dual-source computed tomography system, the angle between the first X-ray detector and the first X-ray source can be optimized so that an optimal or maximum signal of the calibration photons on the first X-ray detector is achieved becomes. An improved signal yield of the calibration photons can be achieved on the first X-ray detector. The energy calibration can be carried out more quickly and / or more precisely.
  • the calibration target is arranged at the intersection of the central beam and the surface normal.
  • the center or a suitable point on the surface of the calibration target or the center of gravity of the calibration target can be arranged at the crossing point.
  • the calibration target can in particular be arranged such that the angle of incidence of the X-ray photons, in particular with respect to the central beam, essentially corresponds to the angle of failure of the calibration photons.
  • the calibration target can alternatively be arranged such that the angle of reflection is almost parallel to the surface normal of the calibration target, the deviation from the surface normal being less than 10 degrees and preferably less than 5 degrees.
  • the surface normal of the detection surface and a surface normal of the calibration target can in particular be arranged at half the angle to one another.
  • the central beam and the surface normal of the calibration target can in particular be arranged at half an angle to one another.
  • a scattered radiation element is arranged on the first X-ray detector, which has a selectable direction, so that essentially only calibration photons strike the partial area of the detection area.
  • the scattered radiation element can have a lamellar or lattice-shaped structure, the passage openings being arranged between the lamellae or the lattice walls.
  • the lamellae or lattice walls can be arranged in parallel or aligned with a common point.
  • the lamellae or lattice walls can in particular have a fixed assignment to one another, which can in particular be mechanically fixed.
  • the lamellae or lattice walls can have an adjustable association with one another.
  • the direction of the scattered radiation element can be selected by changing the position of the scattered radiation element with grating walls or lamellae which are firmly assigned to one another or the adjustable assignment.
  • the direction can in particular denote the transmission direction of the anti-scatter grid.
  • the grid walls or lamellae have a material that absorbs X-rays, for example tungsten.
  • essentially only calibration photons can strike the partial area through the passage openings and the X-ray photons can essentially be shielded from the partial area.
  • a shielding element is arranged such that the partial area of the detection surface is essentially shielded from X-ray photons.
  • the shielding element can in particular shield the entire surface, ie the shielding element preferably has no passage openings.
  • the shielding element can, in particular, shield part of the beam of rays from the first x-ray source from the partial area of the detection area, in particular another part of the beam incident on the calibration target.
  • the shielding element can in particular be arranged between the first X-ray source and the first X-ray detector.
  • the shielding element can be arranged, for example, on the x-ray detector or in the vicinity of the x-ray detector.
  • a particularly effective shielding of the partial area can advantageously be achieved by the selection of suitable absorption properties, such as material which is highly absorbent for X-radiation and a corresponding thickness of the material.
  • a collimator is arranged on the first X-ray source in such a way that the partial area of the detection area is essentially shielded from X-ray photons.
  • a collimator can be arranged after the exit window of the x-ray source.
  • the collimator can in particular have at least two diaphragms, in a special embodiment the collimator can be a multi-leaf collimator. The collimator fades in or collimates the beam.
  • the collimator can be set such that the partial area of the detection area is at least partially shielded by the collimator and the calibration target is illuminated. Shielding on the x-ray source side can thus advantageously be achieved. A proportion of scattered radiation can advantageously be reduced. A particularly effective shielding of the partial area can advantageously be achieved by the selection of suitable absorption properties, such as, for example, high-absorption material for X-ray radiation and a corresponding thickness of the material.
  • the collimator can preferably comprise tungsten as the material.
  • the calibration target comprises a shielding element or a collimator, so that essentially only calibration photons fall on the partial area of the detection area and the partial area of the detection area is essentially shielded from X-ray photons.
  • the shielding element or the collimator can be included in or connected to the calibration target.
  • An alignment of the calibration target and the shielding element or of the collimator can advantageously be defined, in particular the alignment can be optimized to an optimal, set angle.
  • the calibration target has a material that can be excited by means of X-ray photons for fluorescence.
  • the material can be an element, for example Cu, Sn, Ag, Pb, W, I.
  • the fluorescence energy can be in the range between 5 and 85 keV, in particular between 20 and 85 keV. Energy calibration can advantageously be used particularly in applications in medical X-ray imaging.
  • the calibration target has a plurality of materials that can be excited to different fluorescences.
  • the calibration target can preferably have the multiple materials in different, separate areas.
  • the different, separate areas can, for example, be designed as quadrants or circle segments, so that it is possible to switch from one area to the next area by means of a rotating mechanism.
  • the calibration target can have the several materials mixed in a common area.
  • the calibration photons of the different fluorescences can be detected, for example, in a so-called threshold scan.
  • the threshold scan records at least one measured value for a large number of threshold values.
  • the energy calibration can advantageously be carried out essentially without changing the angle.
  • the calibration target can be arranged, positioned or fastened on a patient couch, on a C-arm or on an accessory.
  • the calibration target can be arranged, for example, by clamping on the medical device or essentially free positioning on a patient couch in the medical device.
  • the calibration target can, for example, be arranged or attached to a uroscope, a compression unit or on a movable axis, for example comprising the first X-ray source.
  • the calibration target can alternatively be arranged or attached instead of a known accessory, for example uroscope or compression unit, by means of the existing locking devices.
  • the calibration target can be integrated in an accessory and, for example, additionally have a shielding element which shields the calibration target in imaging mode, so that the imaging operation is undisturbed and the calibration target can be used for energy calibration in calibration operation.
  • the arrangement of the calibration target within the medical X-ray device can advantageously be determined essentially reproducibly by the type and location of the attachment.
  • the invention further relates to a method for energy calibration of a first counting x-ray detector in a medical x-ray device comprising the steps:
  • an angle between the surface normal of the detection surface and a central beam of the beam being set such that the central beam of the beam runs non-surface normal to the detection surface
  • the step of triggering and the step of detecting can form a unit such that the first calibration photons set from a plurality of energy threshold values or reference voltages set are detected, and then the second calibration photons triggered at the plurality of energy threshold values or set Reference voltages are detected.
  • the first or second measurement value can be determined based on the number of detected first or second calibration photons as a function of the energy threshold value, in particular for essentially each detector element individually.
  • the measured value can denote the energy threshold value or the reference voltage, which can be assigned to the energy of the calibration photons.
  • the step of determining the result threshold value is based on the first measured value and the second measured value, preferably more than two measured values are used. For example, a, in particular linear, dependence of the measured values on the respective energy of the calibration photons can be used as the basis for determining the result threshold value.
  • the result threshold denotes the energy threshold or the reference voltage at which the energy threshold of the detector element corresponds to the desired photo energy.
  • the result threshold is in particular a DAC value.
  • the energy threshold can be specified in keV in particular.
  • the individual result threshold value of a detector element as DAC value corresponds in particular to a photon energy in keV, wherein essentially X-ray photons can be detected, for example in imaging mode, with a larger photon energy above this energy threshold.
  • the energy threshold can lie in particular between the first and the second photon energy.
  • the result threshold can be determined or estimated by extrapolation for photo energies above or below both photon energies.
  • the result threshold is set in the detector element.
  • the method is preferably carried out for all detector elements, the individual ones
  • Steps can be carried out in parallel in the individual detector elements. After all detector elements have been set, all detector elements can advantageously have the essentially same energy threshold.
  • the method can advantageously comprise more than two energies of calibration photons and correspondingly more than two measured values, so that the accuracy of the energy calibration can be increased in part.
  • the detection of the first and second calibration photons can in each case comprise a first or second measured value above a threshold value.
  • the first or second measured values can be determined for a large number of threshold values, for example by means of a so-called threshold scan.
  • the measured value can be a count value of calibration photons above the threshold value.
  • the measured value can also give a measure of an energy, for example time-over-threshold.
  • Different calibration targets can be used to absorb the first and second energy.
  • a calibration target with several materials that can be excited to different fluorescences can be used to absorb the first and second energy, in which case a threshold scan is advantageously included in the detection step.
  • a reliable and stable energy calibration of the individual detector elements can advantageously be achieved.
  • the method can further comprise a step of repeating in order to calibrate the entire detection area, with a further partial area being illuminated by the calibration photons. The principles of known methods can be used to particular advantage in the step of determining the result threshold.
  • the first x-ray source and the first x-ray detector can be aligned with respect to one another in such a way that the central beam of the radiation beam extends normal to the detection surface.
  • At least the partial area of the detection surface can be shielded from X-ray photons, for example, by means of a collimator and / or shielding element and / or scattered radiation element.
  • the calibration target can be arranged in such a way that the calibration photons are incident on the partial area and can be detected there.
  • the invention further relates to a calibration target for use in a method according to the invention.
  • the calibration target is designed such that calibration photons can be triggered by means of the X-radiation from the first X-ray source and can be detected in a partial area of the first X-ray detector.
  • the invention further relates to a calibration target for use in a medical Röntgenge advises according to the invention.
  • the calibration target can in particular be reproducibly arranged in the medical X-ray device.
  • the medical device can further comprise a computing unit having means for carrying out a method according to the invention, which has a determination unit for determining the result threshold value and a storage unit for storing the result threshold value.
  • a computer program with program code can be provided in order to carry out the method according to the invention when the computer program is executed on a computer or the computing unit.
  • a computer-readable data carrier with program code of a computer program can also be provided in order to carry out the method according to the invention when the computer program is executed on a computer or the computing unit.
  • FIG. 1 shows a schematic representation of the medical x-ray device according to the invention in a first embodiment
  • FIG. 2 shows a schematic representation of the medical x-ray device according to the invention in a second embodiment
  • FIG. 3 shows a schematic illustration of the medical x-ray device according to the invention in a third embodiment
  • 4 shows a schematic representation of the medical x-ray device according to the invention in a fourth embodiment
  • FIG. 5 shows a schematic representation of the medical X-ray device according to the invention in a fifth embodiment
  • FIG. 6 shows a schematic illustration of the medical x-ray device according to the invention in a sixth embodiment
  • FIG. 7 shows a schematic representation of the medical X-ray device according to the invention in a seventh embodiment
  • the medical x-ray device 1 has a first x-ray source 2 and a first counting x-ray detector 4, the first x-ray source 2 emitting a beam 7 with x-ray photons 8.
  • the first counting x-ray detector 4 has a detection surface 11, an angle 14 between the surface normal 13 of the detection surface 11 and a central beam 12 of the beam 7 being adjustable such that the central beam 12 of the beam 7 in a calibration operation is non-surface normal to the detection surface 11 runs.
  • a calibration target 6 can be positioned in such a way that calibration photons 9 are triggered in the calibration target 6 by means of the x-ray photons 8 and the calibration photons 9 are incident on at least a partial area 15 of the detection area 11, and the partial area 15 of the detection area 11 is essentially shielded from x-ray photos 8 ,
  • the first counting x-ray detector 4 is assigned to the first x-ray source 2.
  • a shielding element 10 is arranged such that the partial area 15 of the detection surface 11 is essentially shielded from X-ray photons 8.
  • the calibration target 6 has a material that can be excited by means of the X-ray photons 8 for fluorescence.
  • the calibration target 6 can have several materials that can be excited to different fluorescences.
  • FIG. 2 shows an exemplary embodiment of a medical X-ray device 1 according to the invention in a second embodiment.
  • a scattered radiation element 18 is arranged on the first X-ray detector 4, which has a selectable direction, so that essentially only calibration photons 9 are incident on the partial area 15 of the detection surface 11.
  • the X-ray photons 8 ' are essentially completely absorbed by the scattered radiation element 18.
  • the first x-ray source 2 is adjustable relative to the first counting x-ray detector 4, in particular is rotatable or movable, for example along the path 17.
  • a collimator 16 is arranged on the first X-ray source 2 in such a way that the partial area 15 of the detection area 11 is essentially shielded from X-ray photons 8 and the calibration target 6 is illuminated with the X-ray photons 8, so that calibration photons 9 are triggered.
  • the fourth embodiment 4 shows an exemplary embodiment of a medical X-ray device 1 according to the invention in a fourth embodiment.
  • the first counting X-ray detector 4 is rotatable about an axis perpendicular to the central beam 12.
  • the shielding element 10 is arranged such that essentially no X-ray photons 8 are incident on the first X-ray detector 4.
  • FIG. 5 shows an exemplary embodiment of a medical X-ray device 1 according to the invention in a fifth embodiment.
  • the first X-ray detector 4 is rotated by the angle 14 with respect to the central beam 12 to such an extent that no X-ray photons 8 are incident directly on the detection surface 11.
  • the back of the first X-ray detector 4 can act as a shielding element 10.
  • the 6 shows an exemplary embodiment of a medical X-ray device 1 according to the invention in a sixth embodiment.
  • the first counting x-ray detector 4 is assigned to a second x-ray source 3 and a second x-ray detector 5 to the first x-ray source 2.
  • the calibration target 6 is arranged at the intersection of the central beam 12 and the surface normal 13.
  • the medical X-ray device is in particular a dual-plane C-arm system.
  • the calibration target 6 ' is arranged on a patient bed 19.
  • the calibration target 6, 6 ' can be arranged on a C-arm or on an accessory.
  • the calibration target 6 comprises the calibration target 6 itself and a shielding element or a collimator, so that essentially only calibration photons 9 are incident on the partial area 15 of the detection area 11 and the partial area 15 of the detection area 11 is essentially shielded from X-ray photons 8.
  • FIG. 8 shows an exemplary embodiment of a method 100 according to the invention for energy calibration of a first counting x-ray detector in a medical x-ray device.
  • a first x-ray source and a first counting x-ray detector are positioned, an angle between the surface normal of the detection surface and a central beam of the beam being set such that the central beam of the beam runs non-surface normal to the detection surface ,
  • first calibration photons having a first energy and second calibration photons having one of the first energy different second energy in at least one calibration target, for example different calibration targets with different materials for triggering a first or second energy or a calibration target with several materials for triggering the first or second energy, triggered by incident X-ray photons of the first X-ray source In the subsequent step of detecting 103, first calibration photons are detected as the first measured value and second calibration photons as the second measured value in a detector element of the first counting X-ray detector.
  • a result threshold value is determined indicatively for a photon energy for the detector element based on the first measured value and the second measured value.
  • the result threshold value is set on the first counting X-ray detector.

Landscapes

  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Molecular Biology (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Apparatus For Radiation Diagnosis (AREA)

Abstract

L'invention concerne un appareil à rayons X médical (1), comportant une première source de rayons X (2) et un premier détecteur compteur de rayons X (4), a. la première source de rayons X (2) émettant un faisceau de rayons (7) pourvu de photons X (8), b. le premier détecteur compteur de rayons X (4) comportant une surface de détection (11), un angle (14) entre la normale de surface (13) de la surface de détection (11) et un rayon central (12) du faisceau de rayons (7) pouvant être réglé de telle sorte que le rayon central (12) du faisceau de rayons (7) s'étend dans une zone d'étalonnage qui ne correspond pas à la normale de surface de la surface de détection (11), c. une cible (6) d'étalonnage pouvant être positionnée de telle sorte que des photons d'étalonnage (9) sont libérés dans la cible d'étalonnage (6) au moyen des photons X (8) et que les photons d'étalonnage (9) sont incidents à au moins une zone partielle (15) de la surface de détection (11), et la zone partielle (15) de la surface de détection (11) étant sensiblement protégée contre les photons X (8).
PCT/EP2019/064778 2018-07-18 2019-06-06 Appareil à rayons x médical et procédé d'étalonnage d'énergie WO2020015920A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102018212001.3 2018-07-18
DE102018212001.3A DE102018212001B4 (de) 2018-07-18 2018-07-18 Medizinisches Röntgengerät und Verfahren zur Energiekalibrierung

Publications (1)

Publication Number Publication Date
WO2020015920A1 true WO2020015920A1 (fr) 2020-01-23

Family

ID=67105975

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2019/064778 WO2020015920A1 (fr) 2018-07-18 2019-06-06 Appareil à rayons x médical et procédé d'étalonnage d'énergie

Country Status (2)

Country Link
DE (1) DE102018212001B4 (fr)
WO (1) WO2020015920A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113534228A (zh) * 2020-04-14 2021-10-22 西门子医疗有限公司 用于在x射线设备中进行剂量测量的方法和设备

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120128131A1 (en) * 2010-11-19 2012-05-24 Siemens Aktiengesellschaft Device And Method For Calibrating An X-Ray Detector, Calibration Apparatus And X-Ray Apparatus
DE102012204350A1 (de) 2012-03-20 2013-09-26 Siemens Aktiengesellschaft Verfahren zur Energie-Kalibrierung quantenzählender Röntgendetektoren in einem Dual-Source Computertomographen
DE102012204360A1 (de) * 2012-03-20 2013-09-26 Siemens Aktiengesellschaft Verfahren und Vorrichtung zur Energiekalibrierung eines quantenzählenden CT-Detektors mittels Fluoreszenzstrahlung
DE102011080656B4 (de) 2011-08-09 2013-11-14 Siemens Aktiengesellschaft Verfahren zur Homogenisierung der Schwellenwerte eines mehrkanaligen quantenzählenden Strahlungsdetektors
US8585286B2 (en) 2008-04-01 2013-11-19 Koninklijke Philips N.V. Spectral detector calibration

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7635221B2 (en) * 2008-01-11 2009-12-22 Siemens Medical Solutions Usa, Inc. Mechanically flexible X-ray imaging system
US10588592B2 (en) * 2014-10-04 2020-03-17 Ibex Innovations Ltd. Scatter in x-ray apparatus and methods of their use

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8585286B2 (en) 2008-04-01 2013-11-19 Koninklijke Philips N.V. Spectral detector calibration
US20120128131A1 (en) * 2010-11-19 2012-05-24 Siemens Aktiengesellschaft Device And Method For Calibrating An X-Ray Detector, Calibration Apparatus And X-Ray Apparatus
DE102011080656B4 (de) 2011-08-09 2013-11-14 Siemens Aktiengesellschaft Verfahren zur Homogenisierung der Schwellenwerte eines mehrkanaligen quantenzählenden Strahlungsdetektors
DE102012204350A1 (de) 2012-03-20 2013-09-26 Siemens Aktiengesellschaft Verfahren zur Energie-Kalibrierung quantenzählender Röntgendetektoren in einem Dual-Source Computertomographen
DE102012204360A1 (de) * 2012-03-20 2013-09-26 Siemens Aktiengesellschaft Verfahren und Vorrichtung zur Energiekalibrierung eines quantenzählenden CT-Detektors mittels Fluoreszenzstrahlung

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113534228A (zh) * 2020-04-14 2021-10-22 西门子医疗有限公司 用于在x射线设备中进行剂量测量的方法和设备

Also Published As

Publication number Publication date
DE102018212001B4 (de) 2021-11-25
DE102018212001A1 (de) 2020-01-23

Similar Documents

Publication Publication Date Title
Shikhaliev Energy-resolved computed tomography: first experimental results
EP0364613B1 (fr) Procédé de fonctionnement d un appareil de tomographie assisté par ordinateur
US8585286B2 (en) Spectral detector calibration
Åslund et al. Scatter rejection in multislit digital mammography
DE102013200021B4 (de) Verfahren zur Kalibrierung eines zählenden digitalen Röntgendetektors, Röntgensysteme zur Durchführung eines solchen Verfahrens und Verfahren zur Aufnahme eines Röntgenbildes
DE10352012B4 (de) Detektormodul für die CT- und/oder PET- und/oder SPECT-Tomographie
WO2012144589A1 (fr) Dispositif d'étalonnage pour détecteur de rayonnement à comptage de photons et procédé d'étalonnage associé
DE102011076781B4 (de) Verfahren zur Korrektur einer Zählratendrift bei einem quantenzählenden Detektor, Röntgen-System mit quantenzählendem Detektor und Schaltungsanordnung für einen quantenzählenden Detektor
DE102014202330B3 (de) Single Source DualEnergy mit zwei Filtern zur Röntgenspektrumsdifferenzierung bei Strahlerblenden mit Schlitzplatte
US10067240B1 (en) X-ray detector system based on photon counting
DE102011056347A1 (de) Integrierte Röntgendetektoranordnung und Verfahren zur Herstellung derselben
DE102011053762A1 (de) System und Verfahren zum Bandpassfiltern für Dualenergie-CT
DE4436688A1 (de) Computertomograph
DE102012204350B4 (de) Verfahren zur Energie-Kalibrierung quantenzählender Röntgendetektoren in einem Dual-Source Computertomographen
DE102013204264A1 (de) Verfahren zur Aufnahme eines Röntgenbildes und Röntgensystem
DE102015217421B4 (de) Spektrale Filterung von Röntgenstrahlung für energieselektive Röntgenbildgebung
EP0028431A1 (fr) Dispositif pour la mesure de la répartition de densité d'un rayonnement dispersé dans une zône plane à examiner
DE102011076351A1 (de) Verfahren und Computertomographiesystem zur Erzeugung tomographischer Bilddatensätze
DE102011005539A1 (de) Verfahren zur Detektion von Röntgenstrahlung und Detektorsystem mit direktkonvertierenden Detektoren
US10646186B2 (en) X-ray CT apparatus, information processing device and information processing method
WO2019017069A1 (fr) Dispositif d'acquisition de distribution de fréquence de hauteur d'onde, procédé d'acquisition de distribution de fréquence de hauteur d'onde, programme d'acquisition de distribution de fréquence de hauteur d'onde, et dispositif de capture d'image de rayonnement
Clements et al. Multi-contrast CT imaging using a high energy resolution CdTe detector and a CZT photon-counting detector
WO2020015920A1 (fr) Appareil à rayons x médical et procédé d'étalonnage d'énergie
DE102004039681B4 (de) Tomographiegerät und Verfahren für ein Tomographiegerät
DE102007027921B4 (de) Sensoranordnung, bildgebende radiologische Anlage und bildgebendes Verfahren

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19733957

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 19733957

Country of ref document: EP

Kind code of ref document: A1