WO2009017348A2 - Filtre optique pour rayon x quasi-monochrome et système d'imagerie à rayons x multi-énergie à rayon x quasi-monochrome - Google Patents

Filtre optique pour rayon x quasi-monochrome et système d'imagerie à rayons x multi-énergie à rayon x quasi-monochrome Download PDF

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WO2009017348A2
WO2009017348A2 PCT/KR2008/004398 KR2008004398W WO2009017348A2 WO 2009017348 A2 WO2009017348 A2 WO 2009017348A2 KR 2008004398 W KR2008004398 W KR 2008004398W WO 2009017348 A2 WO2009017348 A2 WO 2009017348A2
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WIPO (PCT)
Prior art keywords
ray
quasi
monochromatic
energy
reflecting mirrors
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PCT/KR2008/004398
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English (en)
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WO2009017348A3 (fr
Inventor
Young Sei Park
Se Jin Han
Jang Yool Chae
Chang Kyu Kim
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Hanwha L & C Corp.
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Priority claimed from KR1020070075403A external-priority patent/KR100878693B1/ko
Priority claimed from KR1020070091131A external-priority patent/KR100952326B1/ko
Application filed by Hanwha L & C Corp. filed Critical Hanwha L & C Corp.
Publication of WO2009017348A2 publication Critical patent/WO2009017348A2/fr
Publication of WO2009017348A3 publication Critical patent/WO2009017348A3/fr

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    • 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
    • A61B6/4035—Arrangements for generating radiation specially adapted for radiation diagnosis the source being combined with a filter or grating
    • 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
    • A61B6/40—Arrangements for generating radiation specially adapted for radiation diagnosis
    • A61B6/4064—Arrangements for generating radiation specially adapted for radiation diagnosis specially adapted for producing a particular type of beam
    • A61B6/4092—Arrangements for generating radiation specially adapted for radiation diagnosis specially adapted for producing a particular type of beam for producing synchrotron radiation

Definitions

  • the present invention relates, in general, to a quasi-monochromatic x- ray optical filter and a quasi-monochromatic multi-energy x-ray imaging system using the optical filter, and, more particularly, to an optical filter that is capable of filtering a polychromatic x-ray to obtain a quasi- monochromatic x-ray having a desired single energy band or multi-energy band and a quasi-monochromatic multi-energy ⁇ -ray imaging system that is capable of acquiring images, in which the spectrum regions of multi-energy are clearly distinctive and which are clear even after a small exposure, through imaging using quasi-monochromatic multi-energy obtained through the filtering of the optical filter.
  • Electromagnetic waves in the ⁇ -ray region which have wavelengths shorter than those of ultraviolet rays, are suitable for the construction of various types of imaging equipment using the information of transmitted components because they have a characteristic in which part thereof is absorbed by an object but the remaining part thereof passes through the object.
  • the representative examples of such equipment include various types of x-ray imaging equipment for medical diagnoses and inspection equipment used at airports, and the utility of such a technology is widely known.
  • ⁇ 3> In various types of commercial imaging equipment, the material of x-ray emission anodes, output, voltage, current and radiation time are selected to meet the purposes thereof, and then ⁇ -rays are radiated. These x-rays have a wide energy spectrum 101, as shown in Fig. 1.
  • the absorption rate is high in a relatively low-energy region, whereas the absorption rate is low and scattering frequently occurs in a relatively high-energy region, due to characteristics intrinsic to the ⁇ -ray.
  • the low-energy region having a high variability in the absorption rate and a generally high absorption rate is advantageous for the increase in the contrast of an image from the standpoint of the acquisition of images of the human body, there is a possibility that the human body may be damaged by radioactive rays.
  • the high-energy region having a low variability in the absorption rate and a generally low absorption rate has low toxicity to the human body, but it has degraded contrast and low image sharpness due to the scattering of ⁇ -rays.
  • This technology refers to a technology for generating a monochromatic ⁇ -ray having a line spectrum 103 corresponding to a wide energy spectrum or a quasi-monochromatic ⁇ -ray having a narrow spectrum 102, and using it.
  • the quasi-monochromatic ⁇ -ray can be produced using a method of causing a polychromatic x-ray to be reflected from a multi-layer film in which films made of material having a high atomic number and films of material having a low atomic number are alternately arranged and selecting monochromatic light having a specific wavelength based on Bragg' s diffraction law.
  • the Bragg' s diffraction law is expressed as follows:
  • E diffracted energy in kiloelectron Volts (keVs)
  • n is a constant equal to or greater than 1
  • d is a diffraction grating distance in As
  • ⁇ is an incident angle that is formed by an incident beam and an incident surface.
  • Monochromatic light can be obtained by causing polychromatic light to be incident on and be reflected from a single crystal to which Bragg's law is applied.
  • monochromatic light is obtained from a very small part of a wide spectrum, the number of photons of a monochromatic x-ray is very low, compared to an incident ⁇ -ray.
  • monochromatic light produced using an ⁇ -ray having high intensity, which is emitted from a synchrotron has no difficulty with the acquisition of a number of photons sufficient for the purpose of use, it is very useful for imaging, and various effects obtained by the use of monochromatic light have been reported.
  • a synchrotron is not equipment that can be easily and generally used because it is expensive and large.
  • the imaging of a two-dimensional area subject at one time is a very important condition.
  • the width of monochromatic light obtained using an x- ray light source, such as a synchrotron, is merely several millimeters, even when the distance to the source is several meters. Accordingly, a subject having a size larger than the width should be imaged using a scanning method, and a method of obtaining large area emission quasi-monochromatic x-rays so as to image a subject at one time needs to be devised, even when a commercial ⁇ -ray light source is employed.
  • ⁇ -rays 104 and 105 having two respective types of energy which are set in regions respectively lower and higher than that of the K-edge absorption energy 106 of iodine, which is contrast medium material, are radiated, as shown in Fig. 2, and the quality of images is considerably influenced by the shape of an incident beam spectrum and an energy range.
  • K-edge absorption occurs based on an x-ray absorption band attributable to the electron structure of each element.
  • the absorption coefficient rapidly increases at the point where energy exceeds an energy gap, and decreases again when the energy continuously increases above the energy gap. Furthermore, since the energy gap is a value inherent in each element, the K-edge energy varies depending on the element. It is known that the K-edge energy of iodine, which is a widely used contrast medium material, is 33.164 keV. That is, when a contrast medium is used, the ⁇ -ray absorption coefficient is increased, and division into a portion having a high absorption coefficient and a portion having a low absorption coefficient is performed depending on the x-ray energy that is used for imaging.
  • the effect of elimination of a background is excellent when two images that are acquired in energy regions closest to the front and rear portions of a region corresponding to the K-edge energy of the contrast medium material are subtracted from each other, and the contrast of a portion in which the contrast medium is used is maximized.
  • a representative example of radiography using a dual energy subtraction method is mammography. Since the constituent tissues of a mamma have a low ⁇ -ray absorption coefficient, images having high contrast are acquired using energy in the vicinity of 20 keV, which is considerably lower than x-ray energy that are radiated onto other human body portions. In this case, since the quantity of radioactive rays absorbed by the human body is large, a method capable of reducing the dose thereof as much as possible while maintaining contrast has always been the target of research, and a dual energy subtraction method using a quasi-monochromatic x-ray may be a solution thereto.
  • an object of the present invention is to provide an optical filter capable of producing wide-angle quasi-monochromatic light that can obtain a quasi-monochromatic x-ray in which a spectrum in a desired energy band has a slightly narrow width by causing a polychromatic x-ray, obtained using a commercial x-ray generation device, to be incident on a highly efficient Bragg reflecting mirror, and that can image each of the subjects having various areas at one time by regularly arranging a plurality of reflecting mirrors between an x-ray light source and the subject optical filter, and an ⁇ -ray imaging system using the optical filter.
  • Another object of the present invention is to provide a quasi- monochromatic multi-energy x-ray imaging system that generates a quasi- monochromatic x-ray having multi-energy using the optical filter, so that the spectrum regions of the multi-energy are clearly distinguished, and thus clear images can be acquired after a small exposure.
  • a further object of the present invention is to provide a quasi- monochromatic multi-energy x-ray imaging system that performs scanning imaging using a plurality of reflecting mirrors, so that imaging time is reduced and the system can be effectively used for the imaging of a large area subject.
  • the present invention provides a quasi-monochromatic ⁇ -ray optical filter formed by stacking a plurality of reflecting mirrors at a predetermined angle with respect to an incident ⁇ -ray one on top of another in a chamber, wherein a length of each of the respective reflecting mirrors is set between a length that allows all x-rays, incident between neighboring reflecting mirrors, to collide with surfaces of the reflecting mirrors, and a length that allows all x-rays, incident between neighboring reflecting mirrors, to be reflected and be prevented from colliding with back surfaces of the neighboring reflecting mirrors.
  • a multi-layer film the thickness of which gradually increases so that a Bragg condition for reflection of identical specific energy is met, is deposited on each of the reflecting mirrors of the present invention, and a multi-layer film is deposited on each of the reflecting mirrors of the present invention so that an inclination obtained by dividing a difference between thicknesses of a film material pair at both ends of the reflecting mirror by the length is uniform.
  • the multi-layer film is deposited as described above, it is possible to reduce the range of reflected energy deviation in the reflecting mirror.
  • the present invention provides an ⁇ -ray imaging system in which the quasi-monochromatic ⁇ -ray optical filter is disposed between an x- ray light source and an x-ray detection unit.
  • the quasi-monochromatic x-ray optical filter may further include an optical filter alignment unit for moving the quasi-monochromatic x-ray optical filter based on degrees of freedom along three axes, that is, xyz axes, and the optical filter alignment unit may include a mechanism for causing the quasi-monochromatic ⁇ -ray optical filter to perform vibration or pendulum movement in a direction perpendicular to an incident beam.
  • the present invention provides a quasi-monochromatic multi-energy x-ray imaging system including a light source unit for generating and emitting x-rays and enabling a focal spot of the ⁇ -rays to move in a predetermined direction, an optical filter mounted in the light source unit and installed to emit polychromatic ⁇ -rays, emitted from the light source unit, in quasi-monochromatic multi- energy form and radiate the quasi-monochromatic multi-energy onto the subject, and a signal detector unit for detecting the ⁇ -rays having passed through the subject and acquiring multi-energy image information, wherein the optical filter includes a plurality of reflecting mirrors that is installed such that the polychromatic ⁇ -rays are incident at a substantially identical angle and a shutter that is configured to selectively block the quasi- monochromatic multi energy reflected and emitted from the reflecting mirrors, and wherein one or more of the reflecting mirrors on which respective film material pairs having different thicknesses are formed are
  • the present invention provides a quasi-monochromatic multi-energy x-ray imaging system including a light source unit for generating and emitting x-rays and enabling a focal spot of the x-rays to move in a predetermined direction, an optical filter mounted in the light source unit and installed to emit polychromatic x-rays, emitted from the light source unit, in quasi-monochromatic multi-energy form and radiate the quasi-monochromatic multi-energy onto the subject, and a signal detector unit for detecting the x-rays having passed through the subject and acquiring multi-energy image information, wherein the optical filter includes a plurality of reflecting mirrors in which film material pairs have an identical thickness, and a shutter that is configured to selectively block the quasi-monochromatic multi energy reflected and emitted from the reflecting mirrors, and wherein one or more of the reflecting mirrors that have different incident angles for the polychromatic ⁇ -rays are alternately arranged.
  • the imaging system of the present invention produces quasi- monochromatic light using a commercial x-ray light source.
  • the imaging system prevents spectra from overlapping each other while causing the energy and width of quasi-monochromatic light to approach the front and end of the K-edge of an x-ray contrast medium, and thus it provides an improved contrast and sensitivity effect in dual energy subtraction angiography using a contrast medium. Meanwhile, in dual energy imaging using no contrast medium, an energy value and an energy width, which produce great effects, can be adjusted.
  • the optical filter may further include a back slit, the back slit including walls that are formed so as to block polychromatic x-rays passed between the reflecting mirrors and then emitted, and slots that are formed between the walls so as to pass quasi-monochromatic ⁇ -rays, reflected and emitted from the reflecting mirrors, therethrough.
  • the walls and slots of the back slit may be arranged along a concentric circle having a substantially same origin as the concentric circle along with the reflecting mirrors are arranged.
  • the walls of the back slit may be extended such that they can adjust a width of reflected beams reflected from the reflecting mirrors.
  • the quasi-monochromatic multi-energy x-ray imaging system may further include a collimator unit that is provided with a collimator having an opening for adjusting a size of the ⁇ -ray beam that is emitted from the optical filter and radiated onto the subject.
  • the collimator may be installed such that it can be moved to adjust a distance to the light source unit .
  • the reflecting mirrors may be installed such that they can be rotated together at a predetermined angle around a selected point or such that a radius r of a concentric circle along which the reflecting mirrors are arranged can be adjusted,
  • the reflecting mirrors may be installed such that an incident angle of the x-ray is less than 1 degree, and a thickness of a film material pair of each of the reflecting mirrors is set in a range of 1.5 - 8 nm, thereby reflecting a quasi-monochromatic ⁇ -ray in a range of 10 ⁇ 100 keV.
  • the direction of movement of the focal spot of the ⁇ -ray may be set to a rectilinear direction or a direction of rotation.
  • the imaging system of the present invention it is possible to perform imaging using quasi-monochromatic dual energy.
  • the imaging system of the present invention enables various imaging methods, such as a method of dividing reflecting mirrors into reflecting mirrors for high energy and reflecting mirrors for low energy, and performing scanning imaging twice while covering the reflecting mirrors for low energy during high energy imaging and covering the reflecting mirrors for high energy during low energy imaging, a method of alternately mounting two types of reflecting mirrors, performing imaging once, dividing the detection time of a signal detection unit (digital detector) into an appropriate number of frames, accumulating signals, and acquiring images for the respective types of dual energy by separating high-energy and low-energy frames from each other and synthesizing related frames, an energy adjustment method of mounting the same type of reflecting mirrors, performing scanning imaging twice, rotating a reflecting mirror chamber around an axis passing through the thickness of reflecting mirrors after first imaging, changing the energy of reflected quasi- monochromatic light and performing second imaging, a method of performing scanning imaging using a one-row line detector
  • a large area subject can be imaged using a quasi-monochromatic x-ray at a single time.
  • Large area emission can be achieved by stacking a plurality of reflecting mirrors one on top of another, rather than using a single reflecting mirror.
  • quasi- monochromatic energy in various regions can be generated using a single type of optical filter, and effective quasi-monochromatic x-ray images can be acquired practically because the optical filter can be installed in a small space that is formed in the structure of an imaging system using a commercial x-ray source which has not been considerably reconstructed.
  • the spectrum regions of multi-energy can be clearly distinguished from each other, so that clear images can be acquired after a small exposure when adjustment is performed to use an optimum energy value.
  • Fig. 1 is a diagram showing polychromatic, quasi-monochromatic and monochromatic x-rays, which correspond to typical x-ray energy spectra, respectively;
  • Fig. 2 is a diagram showing the dual energy spectra of quasi- monochromatic light and polychromatic light
  • Fig. 3 is sectional views of reflecting mirrors, in which Fig. 3(a) is a diagram of a reflecting mirror without an inclined coating, and Fig. 3(b) is sectional views of reflecting mirrors with inclined coatings! ⁇ 46>
  • Fig. 4 is a schematic diagram showing a quasi-monochromatic x-ray optical filter according to the present invention; ⁇ 47>
  • Fig. 5 is a TEM photo showing the reflecting mirror multi-layer film of embodiment 1;
  • Fig. 6 is a diagram showing the reflected x-ray spectrum, reflectivity and the use of a synchrotron of embodiment 2;
  • FIG. 14(a) to 14(c) are diagrams showing the concept of dual energy scanning imaging using the imaging system of the present invention
  • Fig. 15 is a diagram showing a back slit that constitutes part of the imaging system of the present invention
  • Figs. 16(a) to 16(c) are diagrams showing the arrangements of reflecting mirrors that are used in the imaging system of the present invention
  • Fig. 17 is a diagram showing the quasi-monochromatic dual energy spectrum of the present invention
  • ⁇ 60> Fig. 18 is a diagram showing quasi-monochromatic dual energy x-ray images to which the present invention is applied and an effect image to which a subtraction method is applied.
  • ⁇ 6i> ⁇ Description of reference numerals of principal elements in the drawings ⁇
  • ⁇ 84> 112 reflected quasi -monochromatic x-ray
  • FIG. 4 is a schematic diagram showing the concept of a large area emission ⁇ -ray optical filter according to the present invention.
  • Bragg multi-layer substrates hereinafter referred to as 'reflecting mirrors'
  • 'reflecting mirrors' are perpendicularly erected on a concentric circle of radius r having the focus spot of a polychromatic x-ray light source as its origin 0, and the end points e21 of the surfaces of the reflecting mirrors 110 are located on the concentric circle having the radius r, the surfaces being located on the sides of the reflecting mirrors closest to the origin 0.
  • each of the reflecting mirrors 110 is arranged to be inclined at the same incident angle ⁇ i with respect to a radius line having the origin 0 as its center.
  • the length of the reflecting mirrors 110 is set to L + ⁇ l, and the thickness thereof is set to t.
  • Such an arrangement of the reflecting mirrors 110 allows all reflecting mirrors 110 to have the same incident angle with regard to points where a certain concentric circle having origin 0 as its center is placed, and the respective reflecting mirrors 110 have the same incident angle distribution in the longitudinal direction thereof.
  • the interval dg between the reflecting mirrors 110 is set such that monochromatic light having a specific wavelength can be picked out based on Bragg 1 s diffraction law, and the value of the interval dg is related to L, t, and ⁇ i. That is, when ⁇ i is fixed, dg is calculated if L and t are determined. In contrast, when t and dg are fixed, L is calculated. t is calculated in the same manner.
  • dg is the interval between the arranged reflecting mirrors 110.
  • the value of dg is set.
  • the value of dg is set to a value that maximizes the intensity of a reflected beam.
  • the value of dg that maximizes the intensity of a reflected beam may be determined using the following method.
  • ⁇ 90> With respect to an arbitrary reflecting mirror, assuming that the end point of the surface thereof, which is farthest from the origin 0, is el2, a line that connects the origin 0 with the point el2 has an angle of ⁇ i2 with respect to the surface of the reflecting mirror. Thereafter, a line that connects the origin 0 with the end point el2 of the surface of the reflecting mirror that is farthest from the origin O, is caused to meet the end point of the back surface of its neighboring reflecting mirror that is closest to the origin 0.
  • the reflecting mirrors are arranged at the same intervals dg by repeating the above-described method.
  • the angle between rectilinear lines for two neighboring reflecting mirrors is a divided angle ⁇ that is formed by dividing the portion of a concentric circle, having an origin 0 as the center thereof, where the reflecting mirrors are located, by the number of reflecting mirrors.
  • Methods for overcoming the non-uniformity phenomenon include a method of allowing an amplitude of at least a divided angle ⁇ along a concentric circle of radius r and providing angular velocity that enables pendulum motion to be performed two or more times within imaging time, and a method of causing the entire optical filter to perform reciprocating rectilinear motion at an amplitude corresponding to at least dg and at a frequency v equal to or higher than 2 within imaging time in a direction (y- axis direction) perpendicular to a line that connects the central point c of an optical filter (for example, the central point of a portion which belongs to concentric circles around an origin and on which reflecting mirrors are located) with the center of the circle, in the form of the rectilinear oscillation motion of the optical filter.
  • the present invention proposes a technology for providing a function capable of adjusting a quasi- monochromatic energy within an energy deviation range allowable in actual use while causing a change in the incident angle of each reflecting mirror.
  • the rotation of the reflecting mirrors may be implemented using a method of rotating the reflecting mirrors around an axis located at the center of the arrangement of the reflecting mirrors, indicated by c, in a structure in which the reflecting mirrors are fixedly mounted inside a chamber, such as that shown in Fig. 8.
  • the length of the reflecting mirrors L is the minimum length that allows a polychromatic x-ray having passed through the interval dg between the reflecting mirrors to collide with all the surfaces of the reflecting mirrors.
  • the present invention reveals that an optical filter effective in actual use can be fabricated only by using reflecting mirrors having a length obtained by adding ⁇ l to L for the following reasons.
  • ⁇ 98> More specifically, most of an ⁇ -ray incident on a reflecting mirror is reflected through constructive interference based on Bragg' s diffraction equation, or undergoes destructive interference, is converted into thermal energy and then becomes extinct. Since the front and rear ends of reflecting mirrors having a length of L are inclined at an incident angle, the state in which a depth of penetration sufficient to reflect or block an x-ray is not ensured is established. Accordingly, a low percentage of, that is, part of, a polychromatic x-ray passes straight through a multi-layer film and a substrate.
  • the low energy of an incident beam having a long wavelength becomes extinct, and the high energy thereof having a short wavelength does not become extinct. Since the penetrating beam that does not become extinct degrades the quasi- monochromatic property or causes non-uniformity in an image, it is preferable to eliminate the penetrating beam.
  • the front portion (that is, the front end portion) of a reflecting mirror substrate close to the origin 0 is determined to have no great problem because a penetrating x-ray collides with an adjacently disposed reflecting mirror again and experiences the effect of seeming to pass through a thick object until it completely passes through the end of the reflecting mirror, whereas light incident on the back portion (that is, the back end portion) thereof, which seems to pass through a relatively thin object, has a strong possibility of rectilinear penetration.
  • an extended length ⁇ l is added as a means for increasing the thickness of an object through which a beam passing through a back portion, that is, the back end portion of a reflecting mirror, passes.
  • the minimum value of ⁇ l to be added is determined to be a value that enables all of an incident beam entering at an incident angle ( ⁇ i - ⁇ r) through an interval dg to collide with the reflecting mirrors.
  • a value less than the distance between a subject and the reflecting mirrors is sufficient for the maximum value of ⁇ l if ⁇ > ⁇ i, and the maximum value of ⁇ l may be the distance to a point where a line formed by extending the rear surfaces of neighboring reflecting mirror substrates in the longitudinal direction thereof and a reflected beam reflected from the end points of the reflecting mirrors at an angle of ⁇ i meet each other if ⁇ ⁇ ⁇ i .
  • ⁇ ioo> The optical filter presented in the present invention, as shown in Fig.
  • the optical filter may include a Bragg multi-layer film reflecting mirror 110 and a reflecting mirror chamber 120 for accurately arranging, securing and protecting the reflecting mirror at angles and intervals devised for each purpose.
  • the optical filter may be used in a system that includes a reflecting mirror chamber alignment mechanism including a unit for aligning the reflecting mirror chamber 120 with an ⁇ -ray light source, a unit for providing oscillation or pendulum motion, and a unit for performing fastening to an external frame.
  • Each reflecting mirror includes a multi-layer film which is formed by alternately depositing at least two types of material, that is, a high electron density element material and a low electron density element material, and a substrate on which the film is deposited.
  • a material and manufacturing method that enables a high reflectance for a quasi- monochromatic x-ray, provide an appropriate reflection energy band, provide excellent durability and incur appropriate manufacturing costs may be selected as the material and manufacturing method of the multi-layer film.
  • the incident angle ⁇ i at a point close to the origin and the incident angle ⁇ i2 at a point far from the origin have the relationship of ⁇ i > ⁇ i2, and the sequence of the sizes of reflected energy is reversed in the Bragg's equation.
  • quasi-monochromatic energy varies by a minimum of 5% and a maximum of 50% due to incident angle deviation, and the quasi- monochromatic energy varies considerably as the length L of the reflecting mirror increases.
  • a spatial distribution in which the energy of beams emitted from the reflecting mirrors is increased in the y axis of Fig.
  • the spatial distribution having an energy curve amplifies the non-uniformity of the spatial intensity distribution of a reflected x-ray.
  • ⁇ io2> The reduction in the deviation range of energy reflected from a reflecting mirror is implemented using an inclination coating method of sloping a multi-layer film by gradually increasing the thickness of the multi-layer film in a direction toward the reflecting mirrors L.
  • the thickness of a high and low electron density film pair applied at each of the start and end points of a reflecting mirror can be calculated by substituting incident angles ⁇ i and ⁇ i2, which are formed between rectilinear lines that connect the start and end points of the reflecting mirror with the origin 0 and the reflecting mirror, into Bragg's equation.
  • each reflecting mirror Since a film thickness at either end of each reflecting mirror is obtained by multiplying the thickness of a film material pair by the number of layers, the film thickness is proportional to the thickness of the film material pair. If the thicknesses of film material pairs at both ends of the reflecting mirror are mtl and mt2, respectively, there is the relationship of mt2 > mtl, and the thickness of a film is increased from mtl to mt2 in the longitudinal direction thereof.
  • the thickness of each portion of each reflecting mirror is a thickness that satisfies Bragg's equation, and the extent of thickness (inclination) in the longitudinal direction is increased as the incident angle is close to ⁇ i2, rather than ⁇ i.
  • inclined coating may be applied such that the inclination obtained by dividing the difference in the thickness of the film material pair of each reflecting mirror by the length of the reflecting mirror ⁇ (mt2 - mtl)/L ⁇ becomes uniform.
  • the reflecting mirror can still be used as an effective quasi-monochromatic ⁇ -ray reflecting mirror (refer to Fig. 3).
  • a film applied in an inclined manner can be manufactured using a variety of widely used vacuum deposition processes; only a high electron density material is inclined, only a low electron density material is inclined, or a thickness inclination may be provided to both materials.
  • reference numeral 107 denotes a substrate, and reference numerals 108 and 109 denote coated portions.
  • the energy non-uniformity in the x axis direction is decreased when the divergence angle of a beam is small, the distance from the origin is great and the incident angle is large.
  • the energy non-uniformity is slight when the convergence angle of a commercial ⁇ -ray is equal to or less than 25 degrees, the value r proposed by the present invention is in a range of 50 mm - 500 mm, more preferably in a range of 150 mm ⁇ 350 mm, and there are no shutters that block the upper and lower portions of the x axis direction at an incident angle equal to or less than 1 degree, preferably equal to or less than 0.5 degrees, at distance r.
  • the substrate may be made of various materials, such as glass, various metals or a silicon single crystal wafer, it is preferred that the surface of the substrate be very flat and not rough. More preferably, the substrate has the root mean square of surface roughness equal to or less than 1.0 nm and a low x-ray transparency.
  • Substrate materials having low x-ray transparencies are heavy metals having high atomic numbers, preferably nickel, iron, molybdenum, tungsten and lead. These substrates help block the above-described x-rays that pass straight through the substrate.
  • the efficiency of the optical filter is proportional to the x-ray reflectivity of the reflecting mirror. Since reflectivity is the fraction of specific energy that is reflected, the case where reflectivity is high and the energy resolution of a quasi-monochromatic ⁇ -ray ( ⁇ E/E) is high is highly effective. Accordingly, this feature should be taken into account in the design and manufacture of the multi-layer film of the reflecting mirror.
  • Mo, W, Pt, Re and Au are excellent for the high electron density material of the multi-layer film
  • C, Si, SiC and B4C are excellent as the low electron density material thereof
  • Mo-Si, W- C, W-Si, W- B4C, W-SiC and and Pt-C have high efficiency as the material pair.
  • ⁇ ii4> Another principal factor that determines efficiency in the optical filter is the gap d between a reflecting mirror and a neighboring reflecting mirror.
  • the efficiency of the optical filter increases. Accordingly, in order to reduce the thickness of the substrate used in the reflecting mirror as much as possible and increase the gap, the Bragg film thickness of the reflecting mirror is minimized, so that an incident angle having a large value can be obtained, and the length L of the reflecting mirror is increased as much as possible.
  • the thickness of the substrate may be reduced to the limit where the substrate is still not bent and does not lose flatness, problems difficult to deal with, such as the creation of broken pieces at the time when a glass substrate is fastened to a reflecting mirror chamber, occur and the possibility that an x-ray travels straight and passes through the reflecting mirror.
  • the thickness of the substrate of the reflecting mirror is equal to or less than 1 mm, more preferably 0.5 mm. In order to obtain the best efficiency, a substrate having a thickness of 0.1 mm may be used.
  • reflecting mirrors having short lengths equal to or less than 10 mm, or long lengths equal to or greater than 600 mm may be manufactured and used, a limitation is imposed on the length in terms of practical use.
  • the distance between an ⁇ -ray light source and a subject generally does not exceed 1 m, and thus the length of the reflecting mirror cannot be equal to or greater than that.
  • the width of the reflecting mirror is related to the distance r to the ⁇ -ray light source and the divergence angle of incident light.
  • a commercial polychromatic x-ray diverges in a conical shape the divergence angle is determined depending on the inherent characteristics of an x-ray light source, and the divergence width may be adjusted by disposing a width adjusting shutter between the light source and the optical filter.
  • the width of the reflecting mirror should be increased in order to enable the entire polychromatic x-ray incident light to collide with the reflecting mirror.
  • the divergence angle, r and L are small, the width is reduced.
  • the shape of the reflecting mirror may be designed to conform to the conical beam divergence shape in which the width of a portion close to the origin of light is small and the width of a portion far from the origin is large, it is easy to fabricate the reflecting mirror in a rectangular shape.
  • the outer shape of the reflecting mirror chamber may be formed in a hexahedral shape, a spherical shape or other various shapes having no particular limitation.
  • the reflecting mirror chamber should function to D
  • the chamber alignment mechanism is a device unit that has an important function of aligning an origin with the reflecting mirror arrangement of the reflecting mirror chamber when the x-ray light source is set to the origin shown in Fig. 4.
  • the alignment mechanism of the present invention must include a mechanism for adjusting rectilinear movement with respect to the x, y and z axes and a mechanism for rotating the reflecting mirror chamber around an axis that intersects, at right angles, an arbitrary circumference of radius r along which the reflecting mirrors are arranged, more preferably around an axis that intersects the circumference at the center of the arrangement of the reflecting mirrors shown in Fig. 4.
  • a mechanism for adjusting ⁇ angular movement in the xz plane and ⁇ angular movement in the yz plane is included, the adjustment of the reflecting mirror chamber can be more accurately performed.
  • a micro-positioner and an appropriate motor may be used as a mechanism for performing xyz rectilinear movement.
  • the mechanism for performing xyz rectilinear movement requires a precision equal to or lower than 1/10 mm, and prefers x- and y-axis movement precision to z axis movement precision.
  • the mechanism for rotating the reflecting mirror chamber enables rotation within an angular range of ⁇ 1, and must have at least a resolution of 0.005 degrees.
  • Embodiment 1 manufacture and physical properties of reflecting mirror
  • Reflecting mirrors were manufactured in various sizes based on a variety of substrates using sputtering vacuum deposition.
  • Table 1 lists the manufacturing conditions, numbers of layers, thicknesses, measured using X-Ray Reflection (XRR), and roughnesses of the two material interfaces of the films of several molybdenum/silicon multi-layer film reflecting mirrors that were manufactured by performing sputtering vacuum deposition on 4-in size silicon single crystals.
  • XRR X-Ray Reflection
  • the reflecting mirrors listed in Table 1 are suitable for reflecting x-rays in a range of 10-100 keV at an incident angle less than 1 degree, or are suitable for reflecting x- rays in a range of 15-60 keV at an incident angle less than 0.5 degrees so as to obtain a higher reflectivity.
  • Fig. 5 presents a transmission electron microscopic photo of reflecting mirror # 1.
  • Embodiment 2 (x-ray reflection spectrum of reflecting mirror)
  • Embodiment 3 (reflecting mirror image)
  • Fig. 7 compares an image, acquired by, under the conditions in which the commercial x-ray system of Embodiment 2 was used, radiating a reflected x-ray onto a CDMAM Phantom and capturing an image using a digital detector, with a W positive electrode and 40 kVp voltage polychromatic x-ray image. It was observed that, as a result of comparison in contrast with the polychromatic x-ray in the gold disk portion of the CDMAN Phantom, indicated by the dotted lines in the drawing, the quasi-monochromatic reflected beam was higher in contrast by 18%.
  • Embodiment _4 (manufacture of reflecting mirror chamber, design parameters, and image)
  • Fig. 8 is a drawing of Korean Design Application No. 30-2006-0015261 entitled "Front Filter for X-ray Imaging System.” Groove-type slots formed over and under the chamber accurately hold and fasten the arrangement of reflecting mirrors. When an actual reflecting mirror chamber manufactured based on design parameter values of Table 2 is aligned in a commercial x-ray generation system, a large area CDMAM phantom image can be obtained, as shown in Fig. 9. ⁇ i3i> Embodiment 5 (various energy reflections based on changes in rotation angle of a chamber)
  • Fig. 10 shows an example of the case where the energy value of a reflected beam varies by mounting a plurality of reflecting mirrors in a chamber and adjusting the rotation angle of the chamber to two cases.
  • Fig. 10(a) shows a 13.5 keV quasi-monochromatic reflected beam spectrum that is obtained at an arbitrary rotation angle
  • Fig. 10(b) shows a 17.5 keV quasi-monochromatic reflected beam spectrum that is obtained by manipulating a rotation angle in the same reflecting mirror
  • Fig. 10(c) shows a reflecting mirror chamber image under the condition in which the spectrum is measured.
  • Fig. 11 is a conceptual diagram showing a quasi-monochromatic dual energy x-ray imaging system according to the present invention.
  • the x-ray imaging system of the present invention includes a light source unit 10, a signal detector unit 20 and a collimator unit 30.
  • the light source unit 10 includes an optical filter 40 for filtering a polychromatic ⁇ -ray to obtain a quasi-monochromatic x-ray, and the quasi- monochromatic function of the optical filter 40 is implemented using a multilayer reflecting mirror 42.
  • the multi-layer reflecting mirror 42 has a structure in which a glass substrate 43 having a thickness less than 1 mm and a very flat surface is coated with films 42a and 42b having a thickness in a range of several tens to several hundreds of nm, as shown in Fig. 12. Reflected energy is determined based on an incident angle corresponding to the incident angle of Bragg' s diffraction equation and the thickness of a film material pair.
  • the reflecting mirror 42 reflects a specific energy portion of a primary beam incident on the reflecting mirror, and the spectrum thereof has a slight narrow band width. Since the reflected energy and the band width are properties inherent in the reflecting mirror that are determined by adjusting the incident angle, the material, the thickness of the material pair, and the number of layers of the material pair, it is possible to predict ideal values.
  • an incident angle varies depending on the distance between an inclined reflecting mirror and the focal spot. As the reflecting mirror moves farther from the focal spot in the longitudinal direction identical to a direction in which a beam travels, the incident angle is gradually reduced. For the same distance, the incident angle does not have a single value, but has a width inside a certain range. Accordingly, it is necessary to select a polychromatic x-ray light source suitable for the purpose in question, and manufacture and use the film of the reflecting mirror suitable for that purpose.
  • the thickness of the material pair of the multi-layer film is about several nm
  • the energy of reflected quasi- monochromatic light is set to a value equal to or greater than 10 keV at an incident angle less that 1 degree
  • the limitation in which the thickness of the material pair of the film should be constant is not imposed.
  • a reflected energy value and the width of a spectrum can be determined by adjusting the number of layers between a maximum of 200 and a minimum of 5, with the thickness of a film pair being set between 1.5 and 8 nm and the incident angle being set to a value less than 1 degree.
  • the energy range of a reflected x-ray adjusted under these conditions falls between about 10 keV and 100 keV.
  • the multi-layer reflecting mirrors 42 are arranged to have a preset reflection angle and present intervals and are fastened to the reflecting mirror chamber 44, and the reflecting mirror chamber 44 is fixedly installed in the frame 12 of the light source unit 10 so that it can be arranged in conjunction with the ⁇ -ray light source. That is, the x-ray light source, the reflecting mirror chamber and the reflecting mirrors are integrated into a single body and form the light source unit 10 of a quasi-monochromatic light source device.
  • the quasi-monochromatic light is configured to photograph a subject in a scanning manner while moving recti linearIy along a preset path, as indicated by the focal spots Sl and S2 in Fig. 11 and to photograph a subject in a scanning manner while rotating around the focal spots Sl and S2, as shown in Fig. 14 ⁇ .
  • a plurality of multi-layer reflecting mirrors 42 is fastened to the reflecting mirror chamber 44 so that the multi-layer reflecting mirrors 42 are arranged along a concentric circle at a predetermined reflection angle and predetermined intervals.
  • the reflection angle is an angle that is formed between a radius line that connects the center of a reflecting mirror with the circumference of a concentric circle along which reflecting mirror are arranged and the reflecting mirror, when multi-layer substrate reflecting mirrors satisfying Bragg's diffraction condition are vertically arranged along the concentric circle of radius r that uses the focus spot (Sl or S2) of a polychromatic ⁇ -ray light source as its origin.
  • the interval between the reflecting mirrors may be determined depending on the purpose.
  • the interval between the reflecting mirrors is set to a minimum value so as to filter most x-rays.
  • the minimum value for the interval between the reflecting mirrors is influenced by the length of the reflecting mirrors and the thickness of the substrates, and it is preferred that the minimum value is set such that as many beams pass through the reflecting mirrors as is possible without them passing between the reflecting mirrors.
  • ⁇ i43> Although the penetration depth to which a polychromatic x-ray incident on a reflecting mirror can penetrate without becoming extinct due to scattering and absorption by the film and the substrate material is not great at an incident angle less than one degree, a considerable part of a high- energy region equal to or higher than several tens of keV can penetrate into and pass through the substrate in the case where the energy range of a commercial polychromatic x-ray source is a maximum of one hundred and tens of keV.
  • an x-ray that travels straight may be blocked by covering the back surface of a substrate with heavy metal material in the case where the interval between arranged reflecting mirrors is large or in the case where a small number, for example, equal to or less than 2 or 3, of reflecting mirrors is used, a separate blocking device is required in the case where reflecting mirrors are densely arranged or the number of reflecting mirrors is large.
  • the light source unit 10 of the present invention is configured such that a slit structure is disposed behind reflecting mirrors fastened to the reflecting mirror chamber 44, as shown in Fig. 15, and can block straight beams that pass through the reflecting mirrors without being absorbed and dispersed. Since this structure is disposed along a concentric circle having the same origin as the concentric circle along which the reflecting mirrors 42 are arranged, the structure functions to open or block part of space over the circumference of the concentric circle, and is referred to as a back slit 46.
  • the back slit 46 is configured to have slots 47 that are open such that light passes therethrough and walls 48 that are formed between the slots 47 and block the paths of light.
  • the gap between the slots 47 and the gap between the walls 48 may be set to appropriate values depending on the interval between the reflecting mirrors and the thickness of the substrates. That is, the gap between the slots 47 or the gap between the walls 48, that is, the back slit 46, is determined depending on the width of a reflected beam and the interval based on the geometrical structure of the reflecting mirror chamber shown in Fig. 11.
  • the size (width) of the walls 48 corresponding to the closed portions of the back slit 46 is set such that the thickness portions of the ends of neighboring reflecting mirrors are covered with the respective walls 48, and it may be set by adding an additional length such that the width of reflected beams passing through the slots 47 can be adjusted.
  • Portions 48a added in the direction of the reflection of an x-ray function to block beams reflected from the portions of the reflecting mirrors close to the light source, and portions 48b added in the opposite direction function to block beams reflected from the portions of the reflecting mirror far from the light source.
  • the widths of the reflected beams passing through the back slit 46 are adjusted using the above-described method, so that the beams can function as uniform light during imaging including scanning imaging.
  • a reflecting mirror chamber is fabricated such that it is suitable for two types of incident angles. That is, the reflecting mirror chamber has a structure in which reflecting mirrors can be installed such that the incident angles of x-rays incident on the reflecting mirrors are two types of incident angles.
  • the reflecting mirror chamber may have a structure in which reflecting mirrors are arranged to alternately have different incident angles, as shown in Fig.
  • the reflecting mirror chamber may have a structure in which reflecting mirrors are arranged on both sides of the center of the reflecting mirror chamber so that different incident angles are assigned to either side.
  • ratio of the reflection mirrors having different incident angles to each other is 50%, and the ratio may be appropriately determined in consideration of the adjustment of the amount of light and the convenience of a scanning imaging method.
  • reflecting mirrors including material pairs having different thicknesses may be arranged in a reflecting mirror chamber manufactured to have the same incident angle.
  • the two types of reflecting mirrors may be alternately arranged, two types of pairs of reflecting mirrors may be alternately arranged, or two types of halves of reflecting mirrors may be respectively arranged on both sides of the reflecting mirror chamber, and the ratio of two types of reflecting mirrors to each other are not limited, as in the former case.
  • ⁇ i5i> In still another configuration, it is possible to employ a configuration that is constructed by combining the above-described configurations with each other, that is, a configuration in which reflecting mirrors having different thicknesses are used for incident angles.
  • a method using the energy tunable function of an optical filter may be employed as a method of generating dual energy.
  • all reflecting mirrors are installed in a reflecting mirror chamber and have the same incident angle, if the value of the incident angle is minutely adjusted, it is possible to change the quasi-monochromatic energy band within a specific range. That is, in the case where a plurality of reflecting mirrors is arranged along a concentric circle around the focal spot of an x- ray light source and the radius line of the concentric circle at a uniform inclination, when the reflecting mirrors are rotated around a point located on the central one of the arranged reflecting mirrors together, the inclined angle of all the reflecting mirrors is changed.
  • the incident angles of all the reflecting mirrors are the same before the reflecting mirrors are rotated together, that is, in the state in which the reflecting mirrors are arranged at preset locations, the reflecting mirrors have slightly different incident angles after the reflecting mirrors are rotated around the selected point together.
  • the difference between the inclined angles is greater between reflecting mirrors arranged on the center portion of the reflecting mirrors and reflecting mirrors arranged on both sides of the reflecting mirrors, and is increased as the angle of the rotation of the reflecting mirrors becomes greater. Accordingly, it is preferable to use this method within a minute rotation angle range.
  • the method is useful within the ranges of incident angles and quasi-monochromatic energy that are intended to be used in the present invention.
  • the rotation angle of reflecting mirrors that is used to adjust reflected energy within a range of 30-35 keV, which is less than or greater than the K ⁇ edge energy of an iodine contrast medium is equal to or less than 0.05 degrees when the thickness of the material pairs of the reflecting mirrors is equal to or less than 5 nm.
  • the distance between the focal spot of a light source and the reflecting mirrors is equal to or less than 35 cm, that is, the distance is very short, preferably 15 cm, a similar effect can be achieved by adjusting the distance between the focal spot of the light source focal spot and the reflecting mirrors.
  • the incident angle of a multi-layer film monochromator for acquiring an x-ray in a range of 10 ⁇ 150 keV (effective for acquiring typical x-ray images) through filtering is equal to or less than 1 degree (which is very small)
  • the width of a reflected beam is merely several mm even when the wide divergence angle of a light source and the distance to a detector are taken into account.
  • quasi-monochromatic light acquired through filtering corresponds to part of incident polychromatic light, the amount of light is decreased as long as the power of generation of x-rays of the polychromatic light source is not considerably increased, the degree of which depends on the cases.
  • the present invention presents an optical filter using a plurality of reflecting mirrors and scanning imaging based on an integrated light source in which the optical filter is installed as inherent solution methods.
  • the present invention enables a method of acquiring respective dual energy images at one time, in which case the effect of a reduction in the photographing time is achieved.
  • the scanning imaging method of the present invention enables the same imaging system to perform various types of imaging when an x-ray light source unit performs rectilinear uniform movement along the ⁇ -axis direction shown in Fig. 11 in the state in which a subject and a detector are fixed, or when an ⁇ -ray light source unit is rotated around a focal spot.
  • a method suitable for the status of a subject and the purpose of imaging may be selected and used.
  • scanning imaging is performed in such a way that a bundle of quasi-monochromatic light is subjected to uniform rectilinear motion and/or rotating motion in a range from one end 34 of the opening of the collimator 32 of the collimator unit 30 to the opposite end 35, or in such a way that quasi-monochromatic light is subjected to uniform rectilinear motion and/or rotation motion in the state in which the quasi-monochromatic light is radiated onto the entire opening of the collimator 32 first.
  • a digital detector having a planar two-dimensional pixel arrangement is used as the signal detector unit 20 in which the x-ray signal detection of scanning imaging is performed.
  • the number of reflecting mirrors is equal to or less than 2
  • this does not mean that the use of other types of detectors is limited in respective cases.
  • the focal spot origin of a polychromatic light source is S2
  • light diverges at divergence angle ⁇ l, and one reflecting mirror constituting part of an optical filter reflects light by angle ⁇ , which is part of the divergence angle.
  • a plurality of reflecting mirrors changes the direction of divergence by an incident angle, with the result that a reflected x-ray is emitted from a second virtual light source having a divergence angle of ⁇ 2 and a focal spot origin Sl. Since ⁇ 2 varies depending on the number of reflecting mirrors, the distance to an origin and an incident angle and the reflecting mirrors have thicknesses, an angle obtained by adding a number of ⁇ , equal to the number of reflecting mirrors, together always has a value less than ⁇ 2. Furthermore, since the thickness portions of the reflecting mirrors block polychromatic incident light, the side intensity shape of quasi-monochromatic light emitted from the optical filter is formed like a wave shown in Fig. 13. In Fig.
  • 'A' indicates the intensity profile of a reflected beam in a scanning direction, which is obtained using a single reflecting mirror
  • B indicates the profile of a reflected beam in a rectangular form
  • C indicates the distance between reflected beams.
  • scanning speed may be expressed as the speed of the rectilinear motion of the light source unit, it may be expressed as the division of the opening distance d3 of the collimator adjusted to the size of the subject by the time t that it takes for all the reflected beam bundles of reflecting mirrors to make a complete passage, the division of the left or right distance LO of a subject by t , or the like.
  • the use of an optical filter in which n reflecting mirrors are mounted can increase scanning speed n times and can mitigate limitation to a large area, compared to the use of an optical filter in which one reflecting mirror is mounted.
  • imaging is performed twice
  • image information is acquired through scanning imaging that is performed by moving a light source while emitting quasi-monochromatic light having one type of energy after completely blocking one region of an optical filter that emits one type of energy
  • the light source is returned to a start position after the imaging
  • the energy emission region is switched to the other region
  • an image is acquired through second scanning imaging by using quasi-monochromatic light having another type of energy.
  • a method of blocking either region may be implemented by blocking light incident on a reflecting mirror chamber with a metal plate shutter (a movable lid) through which an ⁇ -ray cannot pass, as shown in Figs.
  • the metal plate shutter 60 may be used.
  • ⁇ i66> When a method of changing energy by slightly changing the incident angle of rotating reflecting mirrors around a focal spot is used, imaging is performed once without the use of a shutter, the incident angle of the reflecting mirrors are adjusted to an original state, and then imaging is performed. In the case where imaging is performed twice at different incident angles, a subject may be imaged at different points of a detector. Since this may cause error when two images are subtracted from each other, correction is required.
  • Quasi-monochromatic light having passed through a plurality of reflecting mirrors has a saw-toothed beam intensity profile A, such as that shown in Fig. 13, due to the shadows of the reflecting mirrors.
  • the profile of a reflected beam has an appropriate shape, preferably the shape of a single rectangle B corresponding to the width of a half tooth of intensity (FWHM)
  • FWHM half tooth of intensity
  • a time frame is designated as L/v when scanning speed is v and the distance between rectangles is L.
  • the width of a pixel line is p
  • L/p lines are present within L, and all pixel lines are classified into two types of dual energy within a single time frame.
  • the same time frame may be applied, in which case scanning imaging can be performed in the state in which the entire subject is exposed to a quasi- monochromatic ⁇ -ray.
  • the minimum number of time frames may be set to one for the time L/v for which movement has been performed over the distance L, and may be set to two until the end of the subsequent time L/v.
  • one or two reflecting mirrors may be used, in which case it is preferable to use a rectilinear-type line detector in which the pixel lines of a detector correspond to reflected beams. In this case, a large area subject can be scan-imaged by simultaneously moving the line detector and the light source together.
  • Iodine contrast medium solutions having different concentrations of 11.6 mgl/ml, 23.1 mgl/ml and 92.5 mgl/ml were put into an acrylic phantom with a square hole having a width of 5 mm and a length of 30 mm, and scanning imaging was performed using quasi-monochromatic dual energy twice under the conditions in which the distance between a light source and reflecting mirrors was 250 mm, an incident angle was 0.25 degrees, the size of a reflecting mirror light source focal spot was 0.3 mm, the length of the reflecting mirrors was 100 mm, the thickness of the reflecting mirrors was 0.5 mm, and the distance between a back slit and the light source was 355 mm.
  • Fig. 17 The spectra of dual energy used in the imaging are shown in Fig. 17, and the central energy values thereof are 30.5 keV and 35.7 keV, which are close to and come before and after the K-edge energy of iodine.
  • Fig. 18(a) shows iodine liquid portions having three types of concentrations that were imaged using 30.5 keV quasi-monochromatic light
  • Fig. 18(b) shows iodine liquid portions having three types of concentrations that were imaged using 35.7 keV quasi-monochromatic light, in which case a clearer image was acquired because the x-ray absorption effect of an iodine contrast medium was great.
  • Fig. 18(a) shows iodine liquid portions having three types of concentrations that were imaged using 30.5 keV quasi-monochromatic light
  • Fig. 18(b) shows iodine liquid portions having three types of concentrations that were imaged using 35.7 keV quasi-monochromatic light
  • 18(c) shows an image after subtraction, which was obtained by performing subtraction between the signals of Figs. 18(a) and 18(b), and is represented in inversed gray scale.
  • the effect in which the background of an acrylic portion, other than a contrast medium portion, was eliminated could be observed.

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Abstract

L'invention concerne un filtre optique à rayon X quasi-monochrome, formant un dispositif de filtrage d'un rayon X polychrome pour obtenir un rayon X quasi-monochrome présentant une bande d'énergie spécifique. Le filtre optique à rayon X quasi-monochrome comprend une pluralité de miroirs réfléchissants sur lesquels sont déposés des films multicouche respectifs réfléchissant de manière sélective les rayons X selon la loi de Bragg, une chambre de miroirs réfléchissants dans laquelle les miroirs réfléchissants sont serrés selon une configuration géométrique spécifique, et un mécanisme d'alignement servant à aligner la chambre dans un dispositif de génération de rayons X commercial. Un système d'imagerie multi-énergie à rayon X quasi-monochrome utilisant le filtre optique permet de distinguer clairement les unes des autres les régions spectrales multi-énergie à l'aide d'un rayon X quasi-monochrome multi-énergie, permettant d'acquérir des images claires, y compris après une petite exposition lorsqu'un réglage est exécuté pour utiliser une valeur d'énergie optimale.
PCT/KR2008/004398 2007-07-27 2008-07-28 Filtre optique pour rayon x quasi-monochrome et système d'imagerie à rayons x multi-énergie à rayon x quasi-monochrome WO2009017348A2 (fr)

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KR1020070091131A KR100952326B1 (ko) 2007-09-07 2007-09-07 준단색 다중 에너지 엑스-선 촬영장치
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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102059406A (zh) * 2009-11-13 2011-05-18 福特汽车公司 通过共用倒角工具表面滚铣准双曲面齿轮齿顶修缘半径
CN102525492A (zh) * 2010-12-31 2012-07-04 上海西门子医疗器械有限公司 一种x射线能谱选择装置
CN103239243A (zh) * 2012-02-09 2013-08-14 上海西门子医疗器械有限公司 曲面镜和包括该曲面镜的x射线数据采集系统
WO2013121418A1 (fr) * 2012-02-13 2013-08-22 Convergent R.N.R Ltd Administration de rayons x guidée par imagerie
US9424958B2 (en) 2011-06-06 2016-08-23 Koninklijke Philips N.V. Multiple focal spot X-ray radiation filtering
US9723230B2 (en) 2012-11-30 2017-08-01 University Of Utah Research Foundation Multi-spectral imaging with diffractive optics
US9986957B2 (en) 2013-11-12 2018-06-05 Samsung Electronics Co., Ltd. Radiation detector and computed tomography apparatus using the same
US10056164B2 (en) 2012-12-03 2018-08-21 Koninklijke Philips N.V. Translating x-ray beam transmission profile shaper

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5744813A (en) * 1994-07-08 1998-04-28 Kumakhov; Muradin Abubekirovich Method and device for controlling beams of neutral and charged particles
JPH1176219A (ja) * 1997-07-09 1999-03-23 Siemens Ag 医療機器のｘ線遮蔽装置
KR20060106573A (ko) * 2005-04-08 2006-10-12 엠엑스에스티, 인크 준단색 엑스-선 필터 및 이를 이용한 엑스-선 촬영 장치
KR20070007512A (ko) * 2005-07-11 2007-01-16 가톨릭대학교 산학협력단 평판형 ｘ선원을 이용한 디지털 ｘ선 영상 시스템 및 이를이용한 ｘ선 영상 검출방법

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5744813A (en) * 1994-07-08 1998-04-28 Kumakhov; Muradin Abubekirovich Method and device for controlling beams of neutral and charged particles
JPH1176219A (ja) * 1997-07-09 1999-03-23 Siemens Ag 医療機器のｘ線遮蔽装置
KR20060106573A (ko) * 2005-04-08 2006-10-12 엠엑스에스티, 인크 준단색 엑스-선 필터 및 이를 이용한 엑스-선 촬영 장치
KR20070007512A (ko) * 2005-07-11 2007-01-16 가톨릭대학교 산학협력단 평판형 ｘ선원을 이용한 디지털 ｘ선 영상 시스템 및 이를이용한 ｘ선 영상 검출방법

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102059406A (zh) * 2009-11-13 2011-05-18 福特汽车公司 通过共用倒角工具表面滚铣准双曲面齿轮齿顶修缘半径
CN102525492A (zh) * 2010-12-31 2012-07-04 上海西门子医疗器械有限公司 一种x射线能谱选择装置
WO2012089794A1 (fr) * 2010-12-31 2012-07-05 Siemens Aktiengesellschaft Appareil pour sélectionner un spectre d'énergie de rayons x
US9424958B2 (en) 2011-06-06 2016-08-23 Koninklijke Philips N.V. Multiple focal spot X-ray radiation filtering
CN103239243A (zh) * 2012-02-09 2013-08-14 上海西门子医疗器械有限公司 曲面镜和包括该曲面镜的x射线数据采集系统
EP2814573A4 (fr) * 2012-02-13 2015-12-23 Convergent R N R Ltd Administration de rayons x guidée par imagerie
WO2013121418A1 (fr) * 2012-02-13 2013-08-22 Convergent R.N.R Ltd Administration de rayons x guidée par imagerie
US9586061B2 (en) 2012-02-13 2017-03-07 Convergent R.N.R Ltd Imaging-guided delivery of X-ray radiation
US10099068B2 (en) 2012-02-13 2018-10-16 Convergent R.N.R Ltd Imaging-guided delivery of X-ray radiation
US9723230B2 (en) 2012-11-30 2017-08-01 University Of Utah Research Foundation Multi-spectral imaging with diffractive optics
US10056164B2 (en) 2012-12-03 2018-08-21 Koninklijke Philips N.V. Translating x-ray beam transmission profile shaper
EP2925230B1 (fr) * 2012-12-03 2020-05-20 Koninklijke Philips N.V. Translation de conformateur de profil d'émission de faisceau de rayons x
US9986957B2 (en) 2013-11-12 2018-06-05 Samsung Electronics Co., Ltd. Radiation detector and computed tomography apparatus using the same
US10751009B2 (en) 2013-11-12 2020-08-25 Samsung Electronics Co., Ltd. Radiation detector and computed tomography apparatus using the same

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