WO2004080308A1 - Bildgerungsverfahren, basierend auf zwei verschiedenen röntgestrahlspektren - Google Patents
Bildgerungsverfahren, basierend auf zwei verschiedenen röntgestrahlspektren Download PDFInfo
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- WO2004080308A1 WO2004080308A1 PCT/EP2004/002094 EP2004002094W WO2004080308A1 WO 2004080308 A1 WO2004080308 A1 WO 2004080308A1 EP 2004002094 W EP2004002094 W EP 2004002094W WO 2004080308 A1 WO2004080308 A1 WO 2004080308A1
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- 238000002083 X-ray spectrum Methods 0.000 title claims abstract description 33
- 238000003384 imaging method Methods 0.000 title claims description 14
- 238000009826 distribution Methods 0.000 claims abstract description 75
- 238000000034 method Methods 0.000 claims abstract description 56
- 239000002872 contrast media Substances 0.000 claims abstract description 43
- 230000001419 dependent effect Effects 0.000 claims abstract description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 4
- 229910052688 Gadolinium Inorganic materials 0.000 claims description 3
- 108090000765 processed proteins & peptides Proteins 0.000 claims description 3
- 229910052769 Ytterbium Inorganic materials 0.000 claims description 2
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 claims description 2
- 150000001413 amino acids Chemical class 0.000 claims description 2
- 229910052797 bismuth Inorganic materials 0.000 claims description 2
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 claims description 2
- 230000008021 deposition Effects 0.000 claims description 2
- -1 dysposium Chemical compound 0.000 claims description 2
- UIWYJDYFSGRHKR-UHFFFAOYSA-N gadolinium atom Chemical compound [Gd] UIWYJDYFSGRHKR-UHFFFAOYSA-N 0.000 claims description 2
- PNDPGZBMCMUPRI-UHFFFAOYSA-N iodine Chemical compound II PNDPGZBMCMUPRI-UHFFFAOYSA-N 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 150000002894 organic compounds Chemical class 0.000 claims description 2
- NAWDYIZEMPQZHO-UHFFFAOYSA-N ytterbium Chemical compound [Yb] NAWDYIZEMPQZHO-UHFFFAOYSA-N 0.000 claims description 2
- 239000000463 material Substances 0.000 description 46
- 238000010521 absorption reaction Methods 0.000 description 20
- 210000001519 tissue Anatomy 0.000 description 19
- 230000003595 spectral effect Effects 0.000 description 11
- 238000001228 spectrum Methods 0.000 description 11
- 230000009466 transformation Effects 0.000 description 9
- 230000003313 weakening effect Effects 0.000 description 9
- 239000000203 mixture Substances 0.000 description 7
- 230000005855 radiation Effects 0.000 description 7
- 239000000126 substance Substances 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 238000002591 computed tomography Methods 0.000 description 6
- 238000004364 calculation method Methods 0.000 description 5
- 238000000354 decomposition reaction Methods 0.000 description 5
- 239000004744 fabric Substances 0.000 description 5
- 238000011156 evaluation Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 3
- 239000011575 calcium Substances 0.000 description 3
- 229910052791 calcium Inorganic materials 0.000 description 3
- 239000003550 marker Substances 0.000 description 3
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- 239000000700 radioactive tracer Substances 0.000 description 3
- 210000004872 soft tissue Anatomy 0.000 description 3
- 238000003325 tomography Methods 0.000 description 3
- 238000004846 x-ray emission Methods 0.000 description 3
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 2
- 210000004204 blood vessel Anatomy 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 229940039231 contrast media Drugs 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 229910052740 iodine Inorganic materials 0.000 description 2
- 239000011630 iodine Substances 0.000 description 2
- 229920002521 macromolecule Polymers 0.000 description 2
- 230000002503 metabolic effect Effects 0.000 description 2
- 210000000056 organ Anatomy 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- CSDQQAQKBAQLLE-UHFFFAOYSA-N 4-(4-chlorophenyl)-4,5,6,7-tetrahydrothieno[3,2-c]pyridine Chemical compound C1=CC(Cl)=CC=C1C1C(C=CS2)=C2CCN1 CSDQQAQKBAQLLE-UHFFFAOYSA-N 0.000 description 1
- 238000012935 Averaging Methods 0.000 description 1
- 208000004434 Calcinosis Diseases 0.000 description 1
- 206010061218 Inflammation Diseases 0.000 description 1
- 206010028980 Neoplasm Diseases 0.000 description 1
- 210000003484 anatomy Anatomy 0.000 description 1
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- 239000008280 blood Substances 0.000 description 1
- 210000004369 blood Anatomy 0.000 description 1
- 230000002308 calcification Effects 0.000 description 1
- 239000012876 carrier material Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000013170 computed tomography imaging Methods 0.000 description 1
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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
- A61B6/48—Diagnostic techniques
- A61B6/481—Diagnostic techniques involving the use of contrast agents
-
- 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
- A61B6/02—Arrangements for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
- A61B6/03—Computed tomography [CT]
- A61B6/032—Transmission computed tomography [CT]
-
- 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
- A61B6/40—Arrangements for generating radiation specially adapted for radiation diagnosis
- A61B6/405—Source units specially adapted to modify characteristics of the beam during the data acquisition process
-
- 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
- A61B6/48—Diagnostic techniques
- A61B6/482—Diagnostic techniques involving multiple energy imaging
-
- 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
- A61B6/50—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment specially adapted for specific body parts; specially adapted for specific clinical applications
- A61B6/504—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment specially adapted for specific body parts; specially adapted for specific clinical applications for diagnosis of blood vessels, e.g. by angiography
-
- 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
- A61B6/582—Calibration
- A61B6/583—Calibration using calibration phantoms
Definitions
- the invention relates to a method for imaging examination of an examination object, which is a patient in particular for medical purposes.
- the method is particularly suitable for use in the context of a tomography method or for use in an imaging tomography-capable examination device, for example in an X-ray computer tomography device.
- Contrast agents are known for example from DE 44 33 564 AI, WO 00/16811 or DE 100 02 939 Cl.
- radiographic processes such as, for example, computer tomography, mammography, angiography, X-ray inspection technology or comparable processes, is initially the depiction of the weakening of an X-ray beam along its path from the X-ray source to the X-ray detector (projection image).
- This weakening is caused by the irradiated media or materials along the beam path, so that the weakening can also be understood as a line integral over the attenuation coefficients of all pixels along the beam path.
- a value normalized to the attenuation coefficient of water is generally used to represent the attenuation distribution. This is calculated from a current attenuation coefficient ⁇ determined by measurement and the Reference attenuation coefficient ⁇ H2 o according to the following equation:
- the generally selected term attenuation value or attenuation coefficient hereinafter denotes both the attenuation coefficient ⁇ and the CT value.
- material and fabric are used interchangeably in the context of this description of the invention. It is assumed that a material can be an anatomical tissue in the context of a medically indicated examination, and conversely tissue in the material and safety test means any material of an examination object.
- a locally increased attenuation value can be attributed either to materials with a higher atomic number, such as calcium in the skeleton or iodine in a contrast medium, or to an increased soft tissue density, such as in the case of a pulmonary nodule.
- the local attenuation coefficient ⁇ at location r depends on the X-ray energy E radiated into the tissue or material and the local tissue or material density p in accordance with the following equation:
- the energy-dependent X-ray absorption of a material is therefore superimposed on the X-ray absorption influenced by the material density p.
- Materials or fabrics of different chemical and physical compositions can therefore have identical attenuation values in the X-ray image.
- the attenuation value of an X-ray image cannot be used to infer the material composition of an examination object.
- atomic number is not used in the strict, element-related sense, but instead denotes an effective atomic number of a fabric or material, which is calculated from the chemical atomic numbers and atomic weights of the elements involved in the structure of the tissue or material.
- the X-ray attenuation values of an examination object are measured with X-rays of lower and higher energy and the values obtained with the corresponding reference values of two base materials such as calcium (for skeletal material) and water It is assumed that each measured value can be represented as a linear superposition of the measured values of the two base materials.
- a skeletal component and a soft tissue component can be calculated for each element of the visual representation of the examination object from the comparison with the values of the base materials so that a transformation of the original recordings into representations of the two Ba Sismaterials skeletal material and soft tissue result.
- the basic material decomposition or the two-spectra method are therefore suitable for the separation or differentiation of predefined anatomical structures or material types in human and animal tissues with very different atomic numbers.
- a method is known from the German patent application with the application number 101 43 131, the sensitivity and meaningfulness of which exceeds that of the base material decomposition and enables, for example, functional CT imaging with high meaningfulness. It enables the calculation of the spatial Distribution of the mean density p () and the effective atomic number Z () from an evaluation of the spectrally influenced measurement data of an X-ray apparatus. This gives very good contrasts, in particular with regard to the chemical and physical composition of the object under examination.
- the representation of the distribution of atomic numbers in the tissue allows, among other things, insights into the biochemical composition of an object under investigation, contrasts due to the chemical structure in organs that have previously been shown to be homogeneous in density, quantitative determination of body components such as iodine or the like, and segmentation of calcifications based on the atomic number.
- This object is achieved according to the invention by a method for the imaging examination of an examination object, in particular a patient, wherein a) a contrast agent is administered to the examination object, b) afterwards at least two spatial distributions of X-ray attenuation values are determined, which X-ray attenuation values each correspond to the represent local X-ray attenuation coefficients ( ⁇ (x, y)) or a variable (C) that is linearly dependent thereon, the two spatial distributions at least comprising:
- a second attenuation value distribution the determination of which is based on a second second X-ray spectrum different from the first X-ray spectrum, c) by evaluating the two weakening value distributions, a spatial distribution of one or more predefined ordinal number values (Z ZI, Z2, ...) or a spatial distribution (Z (x, y)) of non-predefined ordinal number values present in the examination object is determined, which is one Contains information about the distribution of the contrast medium administered in the examination object, and d) the spatial atomic number distribution is used for imaging the contrast medium.
- the invention is based on the idea that the use of contrast media can improve functional imaging in X-ray computer tomography. Contrast agents have so far been used only to e.g. Draw off blood in the absorption against its tissue background. A material- or tissue-selective evaluation did not take place.
- the invention is also based, inter alia, on the knowledge that by adding a contrast agent in a tolerable dose or concentration, an atomic number difference that can be measured by means of two different X-ray spectra can be achieved.
- an ordinal value of the contrast medium can be predefined.
- the method can in particular be combined with the basic material decomposition mentioned at the beginning.
- the spatial atomic number distribution is preferably determined as a two- or three-dimensional field, the respective field value being a local atomic number value at the location represented by the field in question.
- the method may in particular with the method of the aforementioned interpreting ⁇ 's patent application 101 43 131 are combined.
- this patent application is expressly included in the vorlie- constricting patent application, in particular the local patent claims 1 to 7th
- a further two- or three-dimensional field is preferably also determined, the field values of which each represent a local density value.
- the spatial atomic number distribution can be used for imaging, for example, by displaying an image that only contains data from a specific - the value of the atomic number of the contrast medium, e.g. inclusive - ordinal interval or beyond a certain one
- the determined field with the atomic number values and the determined field with the density values are used to calculate a local concentration or a local amount of the contrast medium.
- a contrast medium is understood to mean any means which, after being added to the examination object, in particular after being injected into a patient, lead to a contrast improvement or contrast enhancement in the absorption, that is to say in the X-ray image.
- contrast agents are also understood to mean agents that deposit or accumulate specifically or selectively, for example according to a key-lock principle, only at certain points in the object under examination and thus allow an organ function to be checked. Such latter means can also be so-called markers or tracers.
- Such a marker is composed, for example, of a biological macromolecule, such as an antibody, a peptide or a sugar molecule, with a high affinity for the target structure to be investigated, as well as a contrast substance, for example doped, which is clearly visible in the X-ray image.
- the macromolecule serves, for example, as a so-called “metabolic marker”, which has the effect that the contrast medium, which is also referred to as a metabolic marker, accumulates either exclusively in specific regions, for example tumors, inflammation or other specific sources of disease. Contrast agents are known, for example, from the writings mentioned at the beginning.
- a contrast medium with an atomic number greater than 20 or greater than 40 is preferably used.
- the contrast medium has in particular an atomic number less than 83 or less than 70.
- contrast agents contain gadolinium, iodine, ytterbium, dysposium, iron and / or bismuth.
- the contrast medium contains an organic compound, in particular an aliphatic hydrocarbon, for example sugar, and / or an amino acid or a peptide.
- the contrast medium can be designed for selective deposition at certain points or in certain tissue parts of the examination subject.
- the contrast medium is added in a weight concentration from the range 10 -4 to 10 -'7 , in particular from the range 10 "5 to 10 " 6 .
- 'X-ray spectrum' used in the context of this document has a broader meaning than just the spectral distribution of an X-ray radiation emitted by the X-ray source of the apparatus.
- the resulting effective spectral distribution is also referred to in this document as an X-ray spectrum.
- the two attenuation value distributions do not necessarily have to be taken in succession as two images with different tube voltages. Since each x-ray tube emits a spectrum with a certain width, it is also possible, with a corresponding spectrally selective configuration of an associated receiving unit, to record the two attenuation value distributions as far as possible or completely simultaneously.
- filters and / or two separate existing X-ray detector arrays could be used, for example, in the beam path.
- Attenuation values of the second attenuation value distribution of density and atomic number are determined, and that the spatial atomic number distribution - and optionally a spatial density distribution - is determined from a comparison of the first functional dependency with the second functional dependency and possibly further functional dependencies.
- the functional dependency of the attenuation values on density and atomic number for at least one X-ray spectrum is preferably determined here by means of reference measurement on a calibration sample or in the form of a simulation based on a physical model.
- the weakening value distributions are converted into a distribution of the density and a distribution of the atomic number for each of the assigned weakening values of the first weakening value distribution and the further weakening value distributions on the basis of the determination of a pair of values for density and atomic number so that the pair of values certain functional dependencies of the X-ray absorption of
- Density and atomic number for the first X-ray spectrum and at least one further X-ray spectrum are met.
- the density and atomic number for a picture element can thus be calculated simply as an intersection of the functional dependencies of the mutually associated x-ray absorption values of the recorded distributions of the x-ray absorption values.
- At least one operating parameter of the x-ray tube is changed, the x-ray source in a first operating state having a first x-ray spectrum and in a second operating state a different second x-ray spectrum emitted so that a quick change between two X-ray spectra is possible.
- the detector characteristic was changed, the X-ray detector converting spectral subregions of the X-ray radiation received by the X-ray source into electrical signals that are independent of one another and thereby allowing simultaneous recording of distributions of the X-ray absorption for different X-ray spectra.
- FIG. 3a shows an exemplary functional diagram of a calculation method for determining iso-absorption lines as part of the method according to FIG. 1,
- 3b shows an exemplary flow chart of the transformation of the x-ray attenuation values into values of the material density and atomic number as part of the method according to FIG. 1, and
- Fig. 4 shows two isoabsorption lines of a tissue type with two different X-ray spectra.
- a patient P is administered a tracer or a contrast medium KM, for example by injection into the blood vessels or by swallowing.
- the patient P is then examined in an X-ray computer tomography device 2, which is only indicated, both with the evaluation of a first X-ray spectrum S1 and - simultaneously or in succession - with the evaluation of a second X-ray spectrum S2 (second step 3), which is set by appropriate setting of the X-ray computer tomography device 2 to be selected.
- a attenuation value distribution is generated for each of the x-ray spectra S1, S2, for example as a distribution ⁇ (x, y) or ⁇ 2 (x, y) of the (linear) x-ray attenuation coefficient ⁇ within a transverse slice image with coordinates x and y.
- a computer-assisted transformation of the distributions ⁇ (x, y) or ⁇ 2 (x, y) of the X-ray attenuation coefficient to an atomic number distribution Z (x, y) takes place.
- the atomic number distribution Z (x, y) is used in a fifth step 8 to display a distribution of the contrast medium KM on a monitor 9.
- the concentration of the tracer substance can be determined quantitatively in the case of a known, for example water-like, carrier material.
- the conventional base material decomposition described at the outset can also be used to determine the spatial distribution of two or more predetermined atomic number values ZI, Z2, ... in a transverse layer plane (x, y). Such a distribution can also be used to represent the contrast medium KM in the image.
- the isoabsorption line 11 of FIG. 2 connects all pairs of values (p, Z) with an attenuation value ⁇ or C that is identical for a defined X-ray spectrum.
- the illustration 1 illustrates that information about the type and composition of a tissue or material cannot be derived solely on the basis of the attenuation values of an X-ray image.
- X-rays are weakened to different extents by different materials and depending on the energy of the X-rays. This is due to different weakening mechanisms in the different materials.
- a prerequisite for calculating the atomic number and density distribution in an examination area is at least two X-ray images of the area that are identical in the recording geometry but are made with different energy of the applied X-rays.
- the Z and P resolution can be improved, but this also increases the radiation exposure. In the case of examining a patient, this option is therefore not always available.
- the starting point for the conversion of attenuation value-based image data into distribution images of the ordinal numbers and the material or tissue density is the knowledge of the iso-absorption lines for each X-ray spectrum of an X-ray apparatus.
- x-ray spectrum is not to be understood here as the narrowly defined term of the spectral distribution of an x-ray radiation emitted by the x-ray source of the apparatus, but rather an expanded term that takes into account the different weighting of different spectral ranges of the emission spectrum of the x-ray tube on the x-ray detector side.
- a measured attenuation value therefore results from the direct attenuation of the radiation spectrum emitted by the X-ray tube and the spectral efficiency of the X-ray detector used. Both values are plant-specific quantities and must either be directly which are determined indirectly using the attenuation values of calibration samples. They are the basis for the calculation of the I-absorption lines.
- FIG. 3a three methods 300 for modeling or for calculating a family of iso-absorption lines are outlined, namely theoretical modeling, experimental determination and theoretical modeling with calibration of the curves by experimentally determined parameters.
- isoabsorption lines are to be determined as the attenuation values required to cover the range of X-ray attenuations in the X-ray images. It is not necessary to calculate an iso-absorption line for every theoretically occurring attenuation value; if not calculated isoabsorption lines can be made available by interpolation or other suitable averaging methods.
- step S302 the data of the X-ray emission spectra S (E) specific for a system are first read in with the available tube voltages as parameters.
- the spectral distributions of the X-rays can be experimentally measured for each individual X-ray system beforehand, or the data characteristic for a specific type of X-ray source can be used.
- step S303 Determining the Detek- torapparatefunktion w (E) in step S303.
- the detector arrangement can be measured in advance or data characterizing the detector type, such as its spectral technical specification, can be used.
- step S304 The calculation of the isoabsorption lines in the form of family of curves C ⁇ (p, Z) or ⁇ i (p, Z) is carried out on the basis of a physical model in step S304, which for each relevant combination of S (E) and w (E ) simulates the X-ray attenuation Ci or ⁇ x for materials with different atomic numbers and with different material densities.
- the family of curves of the isoabsorption lines can also be determined experimentally.
- the X-ray attenuations of calibration materials with different density and average atomic number in the X-ray apparatus are measured in different relevant combinations of S (E) and w (E) in step S305.
- the measured values form the bases for the following calculation of the family of curves of iso absorption lines Ci or ⁇ x in step S306.
- the family of curves Ci or ⁇ x modeled on a theoretical basis can be calibrated with experimentally determined x-ray attenuation values.
- the attenuation values necessary for calibrating the theoretical family of curves are measured as described above for step S305 using suitable calibration materials or phantoms in the X-ray system.
- exact knowledge of the X-ray emission spectra S (E) and w (E) is not a prerequisite for this method, but rather parameters of the theoretical modeling of the family of curves of iso absorption lines Ci and] i x in step S308.
- the calibration of the curves in step S309 with the calibration values experimentally determined in step S307 finally defines values for these parameters which are specific for the x-ray emission spectra and detector apparatus functions of the x-ray apparatus.
- the prerequisites for a transformation of image data are the attenuation values of the x-ray radiation when passing through a tissue in image data represent a distribution of the atomic number or the material density in the corresponding tissue.
- the three methods for determining the isoabsorption line can also be used in mixed form. For example, values that can only be determined experimentally inaccurately or only with great effort or not at all can be supplemented with the help of a theoretical model or their accuracy can be specified.
- the data developed using different methods are then combined in step S310 to form a uniform data set and are made available for the image transformations in step S311.
- Figure 3b is a. suitable transformation method 320 for the method according to the invention. It is based on the family of curves of iso-absorption lines, which were determined according to one of the previously described methods 300 and made available as a data set in step S321.
- a transformation takes place pixel by pixel.
- a transformation of an X-ray attenuation value distribution based on two X-ray images taken with different X-ray energy spectra but identical recording geometry is assumed. This is the minimum requirement for carrying out a transformation according to the invention.
- more than two X-ray images can also be used with more than two different X-ray energy distributions.
- the selection of a picture element to be transformed is made in step S322 and in the following step S323 the attenuation values Ci or ⁇ i ⁇ for this picture element are read from the first and C 2 or ⁇ 2 from the second X-ray image.
- the X-ray spectra used for the first X-ray image S ⁇ (E) and the detector apparatus functions wj. (E) and the corresponding values S 2 (E) and w 2 (E) for the second X-ray are queried. image.
- These values form the parameters for a subsequent selection of the isoabsorption lines to be assigned to the respective attenuation values.
- the spectral distributions S ⁇ (E) or Wj. (E) can also be determined indirectly, for example by querying the tube voltages Ui or U 2 used or the operating parameters of the X-ray detectors.
- step S325 a first curve is created from the data set of iso absorption lines provided in step S321, before the conditions Ci and ⁇ i for the parameters Si (E) and i (E) are met and a second curve which meets the conditions C 2 and ⁇ 2 selected for the parameters S 2 (E) and w 2 (E) fulfilled.
- An example of a first isoabsorption line 11 and a second 41 isoabsorption line obtained in this way is shown in FIG.
- the intersection 42 as the intersection of both curves 11 and 41 is calculated in step S326.
- the curve cut 42 can be e.g. by means of a local linear transformation or by means of iterative intersection finding. Since the two curves 11 and 41 represent two different attenuation values for the same image element and therefore for an identical subarea of a examined tissue, both attenuation values must be caused by the same type of material or fabric.
- the coordinates (p, Z) of the curve intersection 42 therefore reflect the material density and the atomic number of the partial tissue area to be assigned to the image element.
- step S327 the ordinal number value Z determined in this way is written into the ordinal number distribution as a corresponding pixel value
- step S328 analogously, the determined material density value p is written into the density distribution.
- Steps S322 to S328 are repeated for all remaining pixels until a final image output can take place in step S329.
- Step S324 can be skipped here since the spectral distributions S (E) and Wi (E) are identical for all picture elements of an image.
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Abstract
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Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/549,269 US7319739B2 (en) | 2003-03-14 | 2004-03-02 | Imaging method based on two different x-ray spectra |
JP2006504507A JP4358852B2 (ja) | 2003-03-14 | 2004-03-02 | 検査対象の画像化検査方法 |
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DE10311628A DE10311628B4 (de) | 2003-03-14 | 2003-03-14 | Bildgebungsverfahren |
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JP (1) | JP4358852B2 (de) |
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JP2006167463A (ja) * | 2004-12-16 | 2006-06-29 | Siemens Ag | 造影剤使用による組織構造のコンピュータ断層撮影画像の作成方法 |
JP2007229464A (ja) * | 2006-02-28 | 2007-09-13 | Siemens Ag | 身体構成要素内の物質の濃度の決定方法および装置 |
WO2009102996A2 (en) * | 2008-02-15 | 2009-08-20 | Mayo Foundation For Medical Education And Research | System and method for quantitative imaging of chemical composition to decompose more than two materials |
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US8218837B2 (en) * | 2008-06-06 | 2012-07-10 | General Electric Company | Material composition detection from effective atomic number computation |
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WO2012165991A1 (en) * | 2011-05-31 | 2012-12-06 | Schlumberger Holdings Limited | Method for determination of spatial distribution and concentration of contrast components in a porous and/or heterogeneous sample |
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CN113281359A (zh) * | 2021-06-22 | 2021-08-20 | 国家卫生健康委职业安全卫生研究中心(国家卫生健康委煤炭工业职业医学研究中心) | 一种基于ct技术进行射线安检物性识别的方法和装置 |
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2003
- 2003-03-14 DE DE10311628A patent/DE10311628B4/de not_active Expired - Fee Related
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2004
- 2004-03-02 US US10/549,269 patent/US7319739B2/en not_active Expired - Fee Related
- 2004-03-02 WO PCT/EP2004/002094 patent/WO2004080308A1/de active Application Filing
- 2004-03-02 CN CN200480001240.8A patent/CN1705457A/zh active Pending
- 2004-03-02 JP JP2006504507A patent/JP4358852B2/ja not_active Expired - Fee Related
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JP2006142011A (ja) * | 2004-11-19 | 2006-06-08 | General Electric Co <Ge> | Ctコロノグラフィ・システム |
JP2006167463A (ja) * | 2004-12-16 | 2006-06-29 | Siemens Ag | 造影剤使用による組織構造のコンピュータ断層撮影画像の作成方法 |
JP2007229464A (ja) * | 2006-02-28 | 2007-09-13 | Siemens Ag | 身体構成要素内の物質の濃度の決定方法および装置 |
WO2009102996A2 (en) * | 2008-02-15 | 2009-08-20 | Mayo Foundation For Medical Education And Research | System and method for quantitative imaging of chemical composition to decompose more than two materials |
WO2009102996A3 (en) * | 2008-02-15 | 2010-01-21 | Mayo Foundation For Medical Education And Research | System and method for quantitative imaging of chemical composition to decompose more than two materials |
Also Published As
Publication number | Publication date |
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JP2006520223A (ja) | 2006-09-07 |
US7319739B2 (en) | 2008-01-15 |
CN1705457A (zh) | 2005-12-07 |
DE10311628B4 (de) | 2006-04-13 |
US20060269043A1 (en) | 2006-11-30 |
JP4358852B2 (ja) | 2009-11-04 |
DE10311628A1 (de) | 2004-10-07 |
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