Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS20040066904 A1
Publication typeApplication
Application numberUS 10/666,188
Publication dateApr 8, 2004
Filing dateSep 10, 2003
Priority dateJan 18, 2002
Also published asUS6647092, US20030138078
Publication number10666188, 666188, US 2004/0066904 A1, US 2004/066904 A1, US 20040066904 A1, US 20040066904A1, US 2004066904 A1, US 2004066904A1, US-A1-20040066904, US-A1-2004066904, US2004/0066904A1, US2004/066904A1, US20040066904 A1, US20040066904A1, US2004066904 A1, US2004066904A1
InventorsJeffrey Eberhard, Reinhold Wirth, Bernhard Claus, Ralph Hewes, Harold Jenkins
Original AssigneeEberhard Jeffrey Wayne, Wirth Reinhold Franz, Claus Bernhard Erich Hermann, Hewes Ralph Allen, Jenkins Harold John
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Radiation imaging system and method of collimation
US 20040066904 A1
Abstract
A radiation imaging system comprises a movable radiation source adapted to be disposed in a plurality of respective radiation source positions; a radiation detector and a collimator assembly configured to displace a collimator in a plurality of respective collimator positions, each of the collimator positions being coordinated with at least one of the radiation source positions such that a radiation beam emanating from the radiation source is collimated to limit radiation incident on the detector to a predetermined exposure area. Another radiation imaging system comprises a movable radiation source; a radiation detector; and a collimator comprising an adjustable geometry aperture assembly configured such that an adjustment of the aperture geometry is synchronized with the movement of the radiation source and coordinated with the radiation source position so as to limit the incident radiation to a predetermined exposure area at the detector.
Images(10)
Previous page
Next page
Claims(44)
1. A radiation imaging system comprising:
a movable radiation source configured to be displaced in a plurality of respective radiation source positions;
a radiation detector;
a collimator assembly, said assembly comprising a collimator, said assembly further being configured to displace the collimator in a plurality of respective collimator positions, each of said collimator positions being coordinated with at least one of said radiation source positions such that a radiation beam emanating from said radiation source is collimated to limit radiation incident on said detector to a predetermined exposure area.
2. The imaging system of claim 1 wherein said collimator assembly further comprises a collimator positioning apparatus for displacing said collimator in respective ones of said collimator positions, each of said collimator positions corresponding to a respective spatial relationship with said radiation source and said detector.
3. The imaging system of claim 2 wherein said collimator positioning apparatus further comprises a displacement mechanism comprising: a rotational displacement mechanism adapted to position the collimator axially with respect to the radiation source and the detector.
4. The imaging system of claim 2 wherein said collimator positioning apparatus further comprises a translational displacement mechanism adapted to position the collimator horizontally with respect to the radiation source and the detector.
5. The imaging system of claim 2 wherein said collimator positioning apparatus further comprises a multi-axis displacement mechanism adapted to position the collimator both axially and horizontally with respect to the radiation source and the detector.
6. The imaging system of claim 1, wherein each one of said collimator positions corresponds to exactly one of said radiation source positions.
7. The imaging system of claim 1, wherein said collimator further comprises an aperture assembly, said aperture assembly being configured to provide an adjustable geometry aperture.
8. The imaging system of claim 1, wherein said collimator further comprises an aperture assembly comprising radiation absorbing material and adapted to provide an adjustable geometry aperture to limit radiation incident on said detector to said predetermined exposure area.
9. The imaging system of claim 7, wherein said aperture assembly comprises a plurality of movable sides.
10. The imaging system of claim 7, wherein said aperture assembly comprises at least one movable side.
11. The imaging system of claim 7, wherein said aperture assembly comprises multiple independently positionable sections with different boundary shapes.
12. The imaging system of claim 11, wherein said multiple sections have linear boundaries.
13. The imaging system of claim 10, wherein said plurality of sides comprise rotationally and translationally movable sides.
14. The imaging system of claim 1, wherein said collimator further comprises an aperture of fixed geometry.
15. The imaging system of claim 14, wherein said fixed geometry aperture has a rectangular cross-section.
16. The imaging system of claim 15, wherein movement of said radiation source relative to said detector is the same as the movement of said radiation source relative to said aperture. detecting the radiation beam on a radiation detector.
17. A method for radiation imaging, comprising:
positioning a radiation source in a plurality of respective radiation source positions;
displacing a collimator in a plurality of respective collimator positions, each of said collimator positions corresponding to a respective one of said radiation source positions such that a radiation beam emanating from said radiation source is collimated to limit the incident radiation to a predetermined exposure area; and
18. The method of claim 17, wherein displacing said collimator comprises:
displacing said collimator such that each of said collimator positions corresponds to a respective spatial relationship with said radiation source and said radiation detector.
19. The method of claim 18, wherein displacing said collimator comprises positioning the collimator axially with respect to the radiation source and the detector.
20. The method of claim 18, wherein displacing said collimator comprises positioning the collimator horizontally with respect to the radiation source and the detector.
21. The method of claim 18, wherein displacing said collimator comprises positioning the collimator both axially and horizontally with respect to the radiation source and the detector.
22. The method of claim 17, wherein displacing said collimator in said plurality of collimator positions is done such that each one of said collimator positions corresponds to exactly one of said radiation source positions.
23. The method of claim 17, wherein displacing said collimator further comprises adjusting the geometry of an aperture.
24. The method of claim 23, wherein adjusting the geometry of the aperture comprises moving a plurality of sides of an aperture assembly of said collimator.
25. The method of claim 23, wherein adjusting the geometry of the aperture comprises moving of at least one side of an aperture assembly of said collimator.
26. The method of claim 17, wherein displacing said collimator further comprises adjusting the geometry of an aperture for limiting radiation incident on said detector to said predetermined exposure area.
27. The method of claim 21, wherein the collimator comprises an aperture, and wherein positioning the radiation source and displacing the collimator are performed to provide movement of said radiation source relative to said detector that is the same as movement of said radiation source relative to said aperture.
28. A radiation imaging system comprising:
a movable radiation source adapted to be disposed in a plurality of respective radiation source positions;
a radiation detector;
a collimator assembly, said assembly comprising a collimator comprising an aperture assembly configured to provide an aperture and a collimator positioning apparatus for displacing said collimator in a plurality of respective collimator positions, each of said collimator positions being coordinated with at least one of said radiation source positions such that a radiation beam emanating from said radiation source is collimated through the aperture to limit radiation incident on said detector to a predetermined exposure area.
29. The imaging system of claim 28, wherein each of said collimator positions corresponds to a respective spatial relationship with said radiation source and said radiation detector.
30. The imaging system of claim 28, wherein each one of said collimator positions corresponds to exactly one of said radiation source positions.
31. The imaging system of claim 28, wherein said aperture assembly is configured to provide an adjustable geometry aperture.
32. The imaging system of claim 31, wherein said aperture assembly comprises a plurality of movable sides.
33. The imaging system of claim 31, wherein said aperture assembly comprises at least one movable side.
34. The imaging system of claim 28, wherein said aperture assembly is configured to provide an aperture of fixed geometry.
35. The imaging system of claim 34, wherein the aperture of fixed geometry has a rectangular cross-section.
36. A radiation imaging system comprising
a movable radiation source;
a radiation detector;
a collimator comprising an adjustable geometry aperture assembly configured such that an adjustment of the aperture geometry is synchronized with the movement of said radiation source and coordinated with the radiation source position so as to limit the incident radiation to a predetermined exposure area at said detector.
37. The imaging system of claim 36, wherein said aperture assembly is configured for adjusting at least one of the position of the aperture and the shape of the aperture.
38. The imaging system of claim 36, further comprising a collimator assembly comprising a collimator positioning apparatus for positioning said collimator.
39. The imaging system of claim 36, wherein said aperture assembly comprises a plurality of movable sides.
40. The imaging system of claim 36, wherein said aperture assembly comprises at least one movable side.
41. The imaging system of claim 36, wherein said aperture assembly comprises multiple independently positionable sections with different boundary shapes.
42. The imaging system of claim 41, wherein said multiple sections have linear boundaries.
43. The imaging system of claim 39, wherein said plurality of sides comprise rotationally and translationally movable sides.
44. A method for radiation imaging, comprising:
moving a radiation source in a plurality of radiation source positions;
adjusting an aperture by synchronizing the aperture geometry adjustment with the movement of said radiation source and coordinating at least one of the position and the shape of said aperture with the respective position of said radiation source such that a radiation beam emanating from said radiation source is collimated to limit the incident radiation to a predetermined exposure area; and
detecting the radiation beam on a radiation detector.
Description
    FEDERAL RESEARCH STATEMENT
  • [0001] The invention was made with Government support under contract number DAMD17988109 awarded by the U.S. Army. The Government has certain rights in the invention.
  • BACKGROUND OF INVENTION
  • [0002]
    The present invention relates generally to X ray radiation imaging systems and more particularly to a method and apparatus for collimating X rays to avoid excess dosage to the patient.
  • [0003]
    Collimators are used in applications where it is desirable to permit only beams of radiation emanating from the radiation source in a particular direction to pass beyond a selected path or a plane. In radiation imagers, collimators are used to ensure that no radiation beams emanating along a direct path from the radiation source miss the detector and hit unintended parts of the object. Collimators are positioned to substantially absorb the undesired radiation. Collimators are traditionally made of a material that has a relatively high atomic number. Collimator design affects the field of view of the imaging system. With the introduction of new imaging applications, the conventional collimators have a disadvantage that excess X rays can spill past the edge of the detector surface (or other predetermined exposure area), or that not the entire detector surface (or other predetermined exposure area) is exposed to incident X rays.
  • [0004]
    In the conventional imaging systems, collimators are used for standard examinations. One such configuration of a collimator comprises an X ray opaque metal with a simple aperture. In another collimator embodiment the aperture is formed by blades that are motor driven to fixed opening sizes. During the course of an X ray exam, typical in tomosynthesis, stereotaxy, stereo imaging and mammography where the X ray source travels in a prescribed arc (or other prescribed trajectory) around the object (patient), it is important to prevent any unnecessary X ray dose to reach the object. Presently the limitation of radiation exposure to the object is governed by US regulation CDRH 21 CFR 1020.30(k).
  • [0005]
    In such advanced imaging systems, it is desirable to minimize the radiation exposure to the patient, minimize the complexity of the collimator in terms of its mechanical, electrical and software implementation, assure high speed of response of the system so that multiple images can be acquired in rapid succession, control the movement of the collimator with respect to other motion in the imaging system, and assure maximum field of view at the detector consistent with system constraints.
  • SUMMARY OF INVENTION
  • [0006]
    Briefly, in accordance with one embodiment of the invention, a radiation imaging system comprises a movable radiation source adapted to be disposed in a plurality of respective radiation source positions, a radiation detector and a collimator assembly. The collimator assembly comprises a collimator and a collimator positioning apparatus which is configured to displace the collimator in a plurality of respective collimator positions. Further, each of the collimator positions is coordinated with at least one of the radiation source positions such that a radiation beam emanating from the radiation source is collimated to limit radiation to a predetermined exposure area on the detector.
  • [0007]
    In accordance with another embodiment of the present invention, a method for radiation imaging comprises positioning a radiation source in a plurality of respective radiation source positions; displacing a collimator in a plurality of respective collimator positions where each of the collimator positions corresponds to a respective one of the radiation source positions such that a radiation beam emanating from the radiation source is collimated to limit the incident radiation to a predetermined exposure area on the detector; and detecting the radiation beam on the radiation detector.
  • [0008]
    In accordance with another embodiment of the present invention, a radiation imaging system comprises a movable radiation source, a radiation detector and a collimator comprising an adjustable geometry aperture assembly configured such that an adjustment of the aperture geometry is synchronized with the movement of the radiation source and coordinated with the radiation source position so as to limit the incident radiation to a predetermined exposure area at the detector.
  • [0009]
    In accordance with another embodiment of the present invention, a method for radiation imaging, comprises moving a radiation source in a plurality of radiation source positions; adjusting an aperture by synchronizing the aperture geometry adjustment with the movement of the radiation source and coordinating at least one of the position and the shape of the aperture with the respective position of the radiation source such that a radiation beam emanating from the radiation source is collimated to limit the incident radiation to a predetermined exposure area; and detecting the radiation beam on a radiation detector.
  • BRIEF DESCRIPTION OF DRAWINGS
  • [0010]
    These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
  • [0011]
    [0011]FIG. 1 illustrates a system block diagram of an imaging system according to one embodiment of the present invention.
  • [0012]
    [0012]FIG. 2 illustrates a plurality of radiation source positions according to one embodiment of the present invention.
  • [0013]
    [0013]FIG. 3 illustrates a collimator assembly including a collimator in one embodiment of the invention.
  • [0014]
    [0014]FIG. 4 illustrates use of a traditional collimator in a Mammography system, depicting the different field of views at the detector for different radiation source positions and respective collimator aperture geometry configurations.
  • [0015]
    [0015]FIG. 5 illustrates the shape of the collimated beam falling onto the detector plane, relative to the detector, for a fixed rectangular aperture, according to one embodiment of the invention corresponding to the system geometry depicted in FIG. 2 and a stationary (i.e., not moving) collimator.
  • [0016]
    [0016]FIG. 6 illustrates the shape of the collimated beam falling onto the detector plane, relative to the detector, for a fixed rectangular aperture, according to another embodiment of the invention corresponding to the system geometry depicted in FIG. 2 for a translatable collimator.
  • [0017]
    [0017]FIG. 7 illustrates one embodiment of the invention wherein projection of the collimator aperture coincides exactly with the active area of the detector.
  • [0018]
    [0018]FIG. 8 illustrates one embodiment of the invention where the movement of the radiation source with respect to the detector is the same as the movement of the radiation source with respect to the aperture and shows the geometric relationships for a vertical position of the X Ray source.
  • [0019]
    [0019]FIG. 9 illustrates another embodiment of the invention where the movement of the radiation source with respect to the detector is the same as the movement of the radiation source with respect to the aperture and shows the geometric relationships with the radiation source rotated at an angle.
  • [0020]
    [0020]FIG. 10 is a top view of an embodiment of the invention wherein an aperture assembly is configured to provide an adjustable geometry aperture.
  • DETAILED DESCRIPTION
  • [0021]
    One embodiment of the present invention is a radiation imaging system 1, as illustrated in FIG. 1, comprising a movable radiation source 2, a radiation detector 3, and a collimator assembly 4. As the radiation source moves relative to an object 14, it assumes a plurality of radiation source positions resulting in the radiation beam emanating from the radiation source intersecting the object at various angles, as shown in FIG. 2. The collimator assembly 4, which is typically in a fixed spatial relationship to the X ray source has flexibility to be configured to position the collimator to limit the radiation incident on the detector to a predetermined exposure area. The predetermined exposure area typically comprises a region of interest for a particular imaging task, an active area of the detector, or the area of the X ray image receptor. The radiation source is configured to be displaced in a plurality of radiation source positions with respect to the object 14, by a radiation source positioner 17, fed by a generator 16 and a system controller 15, comprising an electromechanical system 13 and embedded software. “Movable radiation source” means that the source is free to travel in any direction typical in tomosynthesis and related applications. Non-limiting examples of imaging systems wherein embodiments of the present invention are particularly useful include tomosynthesis, stereotaxy, stereo imaging, for example in mammographic imaging systems.
  • [0022]
    [0022]FIG. 1 also illustrates the collimator assembly 4 according to one embodiment, which includes a collimator 5, and a collimator positioning apparatus 6. The collimator positioning apparatus is configured to displace the collimator to have a plurality of collimator positions such that each collimator position is coordinated with at least one of the radiation source positions. The collimator positioning apparatus is configured to provide movement to the collimator so that each of the collimator positions relates to at least one specific radiation source position at any given time during the imaging process. Further, the movement of the collimator and the radiation source are synchronized such that movement of the collimator occurs in the same time interval as the movement of the radiation source, and both are moving in a coordinated fashion.
  • [0023]
    In one embodiment, the movement of the collimator is also controlled so that each collimator position corresponds to a specific spatial relationship with radiation source and detector. Spatial relationship is defined as the relationship of the collimator position with the position of the radiation source and the radiation detector in the three dimensional space containing the source, collimator and detector. This coordination of the collimator position with the positions of the radiation source and the detector results in collimating and limiting the radiation beam from the radiation source to a predetermined exposure area on the detector and thus avoiding exposure of the object 14 to x-rays that do not contribute to the image formed at the detector. Spillage is defined as X rays emanating from the radiation source, which pass through the collimator aperture along a direct path from the radiation source, and do not hit the detector or the predetermined exposure area on the detector. That is, these X rays do not contribute to the image formed at the detector.
  • [0024]
    In one embodiment, the movement of the collimator assembly and coordination of the collimator position with at least one of the radiation source positions is achieved through a collimator positioning apparatus 6, as shown in FIG. 1, which comprises an electro-mechanical system 13 and a software program of a system controller which computes the positions on the basis of input signals and generates an output signal for providing the desired movement of the collimator.
  • [0025]
    The displacement by the collimator positioning apparatus results in different configurations of the collimator assembly. Each configuration corresponds to a specific collimator position. Further, the collimator assembly is configured to displace the collimator in a plurality of collimator positions with respect to the radiation source, each one of the collimator positions corresponding to one of the radiation source positions.
  • [0026]
    Typically the collimator positioning apparatus 6 has a displacement mechanism 7. In one embodiment the displacement mechanism comprises a rotational displacement mechanism, for positioning the collimator axially as shown in FIG. 7, that is, at an angle, with respect to the radiation source and the detector to achieve a rotational displacement. In another embodiment, the displacement mechanism comprises a translational displacement mechanism, for positioning the collimator horizontally with respect the radiation source and the detector to achieve a translational displacement. In still another embodiment, the displacement mechanism comprises a multi-axis displacement mechanism, for positioning collimator both axially and horizontally with respect to the radiation source and the detector to achieve multi axis displacement.
  • [0027]
    The imaging system is typically coupled to a system controller, which includes a software program to calculate the various displacements and positions of the movable elements of the imaging system including the radiation source, the collimator assembly and the collimator. The system controller is programmed to control the collimator positioning apparatus so as to displace the collimator in plurality of collimator positions. In a more specific embodiment, the displacement of the collimator position with respect to the radiation source corresponds to the respective displacement of the radiation source with respect to the detector.
  • [0028]
    In one embodiment, the aperture assembly has a fixed geometry aperture, that is an aperture made of fixed sides 18. In a more specific embodiment, as shown in FIG. 3, the fixed geometry aperture has a rectangular cross-section. In an even more specific embodiment, aperture 11 is positioned within an aperture plate 23 which is movably mounted relative to a base plate 25 via guide wheels 27, drive belt 21, and stepper motor 20. If the base plate opening 29 is sized such that movement of aperture plate 23 potentially exposes X-rays through opening 29, it is useful to mechanically couple sliding plates 31 to aperture plate 23 to prevent such exposure.
  • [0029]
    In another embodiment, the collimator further comprises an aperture assembly 10, configured to provide an adjustable geometry aperture 11 as shown in FIG. 10. In a more specific embodiment, the aperture assembly has at least one side 19 movable rotationally, translationally, or a combination thereof.
  • [0030]
    Alternatively or additionally, the aperture assembly comprises a plurality of movable sides 19. In another embodiment the aperture assembly comprises multiple sections, with different boundary shapes that can be independently positioned to form an adjustable geometry aperture. Further in another embodiment the multiple sections can have linear boundaries that can be independently positioned. Another embodiment comprises a plurality of sides movable both rotationally and translationally. The aperture assembly typically comprises a radiation absorbing material such as tungsten or some other high atomic number (greater than about 74, for example) material and is adapted to adjust aperture geometry to limit radiation incident on the detector to the predetermined exposure area.
  • [0031]
    When the radiation source moves from one position to the next, the aperture is adjusted accordingly. The movement of radiation source and adjustment of aperture are synchronized, that is, their timing is coordinated. Furthermore, at least one of the position and the shape of the aperture during exposure (i.e., at the instant an image is acquired) is coordinated relative to the position of the radiation source, and relative to the position of the detector. The fact that the position of the aperture is appropriately coordinated with the position of source and detector ensures that no radiation spills beyond the edge of the detector (or active area/predetermined exposure area). In one embodiment, synchronization and position coordination are controlled by the stepper motor 20 and drive belt 21 (such as shown in FIG. 3, for example), driven by system controller 15 and a generator 16 (shown in FIG. 1).
  • [0032]
    The collimator is typically mounted as close to the focal spot as possible, to minimize size and weight and maximize speed of operation. One use of such a collimator assembly is in a mammography system, where the rotation axis of the tube arm is about 22 cm above the face of the detector. In this geometry, the X ray beam is not centered on the detector except for exposures taken at the vertical (0 degree) position.
  • [0033]
    The intersection of the center of the X-ray beam with the image receptor at various angles of tube inclination is shown in FIG. 4. The width of a conventional adjustable collimator aperture, which is symmetric with respect to the center of the beam, has to be decreased with increasing tube inclination angle, in order to avoid any spill beyond the edge of the detector. As shown in FIG. 4, the resulting area of exposure on the detector is very small (about 35 mm in width or smaller, for example) for high tube angles (greater than about 24 degrees, for example) and is not practical. In one embodiment of the present invention one uses a translatable collimator with a fixed rectangular aperture. Using this embodiment, one can achieve almost optimal coverage of the detector, without any spill beyond the edge of the detector. FIGS. 5 and 6 show the shape of the collimated beam falling onto the detector, for a fixed rectangular aperture. FIG. 5 illustrates a stationary (i.e., not moving) collimator, with spill beyond the edge of the detector. FIG. 6 illustrates a translatable collimator, with no spill, and for every angle of inclination of the tube, almost all of the detector surface is irradiated by the beam.
  • [0034]
    In one embodiment of the invention, at least one of the shape of the collimator aperture and the movement of the collimator is controlled such that the relative position of the radiation source with respect to the collimator aperture is the same (meaning identical up to a magnification or scaling factor) as the relative position of the radiation source with respect to the detector. The advantages are that there is no spill of X rays beyond the edge of the active area of the detector and there is no shadow of the collimator falling on the active area of the detector, which results in an optimal field of view. FIG. 7 illustrates the relative positions of radiation source (FS) and the position of the collimator 5 (with an aperture defined by points AB) with respect to the detector 3 (defined at points CD) and a rotation point P. In this embodiment, the generalized pyramid defined by the set of points [FS,C,D] is a magnified or scaled version of the generalized pyramid defined by the set of points [FS,A,B]. In one embodiment of the invention the magnification or scaling is kept constant for plurality of radiation source positions. In FIG. 7, the desired scaling is achieved when distance A1 B1 equals distance A2B2, and they are both equal to “s” times the distance CD, where “s” is the magnification or scaling factor. In one embodiment, an essentially similar mechanical arrangement, a scaled down version in size by a factor “1/s” as defined earlier is used to move the collimator relative to the radiation source, as is used to move the radiation source relative to the detector. Referring to FIGS. 8 and 9, the geometry of the set of points [FS,A,B,Q] is a magnified or scaled version of the geometry of the points [FS,C,D,P] and rotation of the radiation source around point P corresponds to the rotation of the collimator around point Q to optimally position the collimator. One geometry being a magnified or scaled version of the other geometry means that any point in the first geometry has a corresponding point in the second geometry; further, that the distance between any two points in the first geometry is equal to “s” times the distance between the corresponding points in the second geometry, where “s” is the magnification or scaling factor, and that the line passing through the two points in the first geometry has the same orientation as the line passing through the corresponding two points in the second geometry. FIG. 8 illustrates one embodiment of the invention where the movement of the radiation source with respect to the detector is the same (up to a magnification or scaling factor) as the movement of the radiation source with respect to the aperture and shows the geometric relationships for a vertical position of the X Ray source, and FIG. 9 illustrates another embodiment of the invention where the movement of the radiation source with respect to the detector is the same (up to a magnification or scaling factor) as the movement of the radiation source with respect to the aperture and shows the geometric relationships with the radiation source rotated at an angle. For ease of interpretation, in FIG. 9 the radiation source is drawn in the same position as in FIG. 8, with the radiation detector and the collimator rotated correspondingly.
  • [0035]
    Another embodiment of the present invention is a method of radiation imaging, which includes positioning of a radiation source in a plurality of radiation source positions, displacing the collimator in a plurality of respective collimator positions such that each collimator position corresponds to a respective one of the radiation source position to collimate and limit the radiation beam emanating from the radiation source to a predetermined exposure area and detecting the radiation beam on a radiation detector.
  • [0036]
    In another embodiment of the present invention, a radiation imaging system comprises: a movable radiation source; a radiation detector; and a collimator comprising an adjustable geometry aperture assembly configured such that an adjustment of the aperture geometry is synchronized with the movement of said radiation source and coordinated with the radiation source position so as to limit the incident radiation to a predetermined exposure area at said detector. The above described more specific aperture assembly embodiments are also applicable in this embodiment. The adjustable aperture geometry embodiment can be used to obviate the need for changing collimator positions as described above with respect to the displaceable collimator embodiment and may be used independently of or in combination with the displaceable collimator embodiment.
  • [0037]
    As described above, adjustment of the aperture geometry is synchronized with the movement of said radiation source by coordinating their timing, and the aperture geometry adjustment is further coordinated (i.e., at the instant an image is acquired) relative to the position of the radiation source, and relative to the position of the detector. The fact that the position of the aperture is appropriately coordinated with the position of source and detector ensures that no radiation spills beyond the edge of the detector (or active area / predetermined exposure area). In one embodiment, synchronization and position coordination are controlled by the stepper motor and drive belt mechanism driven by a system controller and a generator.
  • [0038]
    Another embodiment of the present invention is a method for radiation imaging, which includes moving a radiation source in a plurality of radiation source positions, adjusting an aperture by synchronizing the aperture geometry adjustment with the movement of the radiation source and coordinating at least one of the position and the shape of the aperture with the respective position of the radiation source such that a radiation beam emanating from the radiation source is collimated to limit the incident radiation to a predetermined exposure area and detecting the radiation beam on a radiation detector.
  • [0039]
    While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.
Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US4190773 *Jul 1, 1977Feb 26, 1980Braden Arthur BShutter for rotating source CT scanner
US4991189 *Apr 16, 1990Feb 5, 1991General Electric CompanyCollimation apparatus for x-ray beam correction
US5050199 *Jun 15, 1990Sep 17, 1991Kabushiki Kaisha ToshibaRadiographic apparatus
US5231654 *Dec 6, 1991Jul 27, 1993General Electric CompanyRadiation imager collimator
US5231655 *Dec 6, 1991Jul 27, 1993General Electric CompanyX-ray collimator
US5293147 *Mar 17, 1993Mar 8, 1994Littelfuse, Inc.Automotive high current fuse
US5299250 *Dec 14, 1992Mar 29, 1994Siemens AktiengesellschaftComputer tomography apparatus with compensation for focus migration by adjustment of diaphragm position
US5303282 *Mar 15, 1993Apr 12, 1994General Electric CompanyRadiation imager collimator
US5349625 *Mar 11, 1993Sep 20, 1994Siemens AktiengesellschaftX-ray diagnostics installation for peripheral angiography examinations
US5369678 *Jun 29, 1992Nov 29, 1994Siemens Corporate Research, Inc.Method for tracking a catheter probe during a fluoroscopic procedure
US5377252 *Dec 10, 1993Dec 27, 1994Siemens AktiengesellschaftComputer tomography apparatus with beam thickness adjustment
US5430298 *Jun 21, 1994Jul 4, 1995General Electric CompanyCT array with improved photosensor linearity and reduced crosstalk
US5481586 *Feb 7, 1995Jan 2, 1996Bennett X-Ray TechnologiesAutomatic position control system for x-ray machines
US5684855 *Feb 15, 1996Nov 4, 1997Kabushiki Kaisha ToshibaX-ray CT scanner
US5751781 *Oct 4, 1996May 12, 1998Elekta AbApparatus for treating a patient
US5754622 *May 3, 1996May 19, 1998Siemens Medical Systems, Inc.System and method for verifying the amount of radiation delivered to an object
US6055295 *Jan 29, 1998Apr 25, 2000Siemens Corporate Research, Inc.Method and apparatus for automatic collimation in x-ray peripheral imaging
US6173039 *Aug 25, 1998Jan 9, 2001General Electric CompanyVariable aperture z-axis tracking collimator for computed tomograph system
US6215848 *Dec 9, 1998Apr 10, 2001U.S. Philips CorporationForming an assembled image from successive X-ray images
US6320929 *Feb 8, 2000Nov 20, 2001Siemens AktiengesellschaftMethod for scanning an examination subject with a CT device
US6339636 *Mar 20, 2000Jan 15, 2002Fuji Photo Film Co., Ltd.Radiation image recording method and apparatus
US6445761 *Mar 11, 1998Sep 3, 2002Hitachi Medical CorporationX-ray computerized tomograph including collimator that restricts irradiation range of X-ray fan beam
US6501828 *Oct 20, 2000Dec 31, 2002Siemens AktiengesellschaftMethod and apparatus for influencing X-rays in a beam path
US6507642 *Sep 12, 2001Jan 14, 2003Ge Medical Systems Global Technology Company, LlcCollimator control method and apparatus, and X-ray CT apparatus
US6618465 *Nov 12, 2001Sep 9, 2003General Electric CompanyX-ray shielding system and shielded digital radiographic inspection system and method
US6683935 *Sep 28, 2001Jan 27, 2004Bio-Imaging Research, Inc.Computed tomography with virtual tilt and angulation
US6898269 *Feb 10, 2003May 24, 2005Ge Medical Systems Global Technology Company, LlcMethods and apparatus for x-ray images
US6940948 *May 29, 2000Sep 6, 2005Ddi Direct Digital Imaging AgDigital X-ray scanning apparatus
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US7869563Nov 23, 2005Jan 11, 2011Hologic, Inc.Integrated multi-mode mammography/tomosynthesis x-ray system and method
US7939807 *May 18, 2009May 10, 2011Cnr Consiglio Nazionale Delle RichercheScintigraphic device with spatial super-resolution
US8031834Oct 6, 2009Oct 4, 2011Siemens AktiengesellschaftTomosynthesis apparatus and method to operate a tomosynthesis apparatus
US8093572 *Jun 29, 2007Jan 10, 2012Accuray IncorporatedIntegrated variable-aperture collimator and fixed-aperture collimator
US8175219Nov 29, 2010May 8, 2012Hologic, Inc.Integrated multi-mode mammography/tomosynthesis X-ray system and method
US8565374May 2, 2012Oct 22, 2013Hologic, Inc.Integrated multi-mode mammography/tomosynthesis x-ray system and method
US8787522Oct 5, 2011Jul 22, 2014Hologic, IncUpright x-ray breast imaging with a CT mode, multiple tomosynthesis modes, and a mammography mode
US9066706Oct 21, 2013Jun 30, 2015Hologic, Inc.Integrated multi-mode mammography/tomosynthesis x-ray system and method
US9084579Apr 28, 2014Jul 21, 2015Hologic, Inc.Matching geometry generation and display of mammograms and tomosynthesis
US9095306Dec 24, 2008Aug 4, 2015Hologic, Inc.Image handling and display in X-ray mammography and tomosynthesis
US9180312Nov 22, 2011Nov 10, 2015Hologic, Inc.Brachytherapy device for asymmetrical irradiation of a body cavity
US9248311Feb 11, 2009Feb 2, 2016Hologic, Inc.System and method for modifying a flexibility of a brachythereapy catheter
US9415239Nov 18, 2011Aug 16, 2016Hologic, Inc.Brachytherapy device for facilitating asymmetrical irradiation of a body cavity
US9460508Jun 17, 2015Oct 4, 2016Hologic, Inc.Image handling and display in X-ray mammography and tomosynthesis
US9498175Oct 18, 2013Nov 22, 2016Hologic, Inc.System and method for low dose tomosynthesis
US9549709Sep 26, 2014Jan 24, 2017Hologic, Inc.Integrated multi-mode mammography/tomosynthesis X-ray system and method
US9579524Feb 11, 2009Feb 28, 2017Hologic, Inc.Flexible multi-lumen brachytherapy device
US9623260Apr 11, 2013Apr 18, 2017Theragenics CorporationExpandable brachytherapy device
US9808214Jul 14, 2014Nov 7, 2017Hologic, Inc.Upright X-ray breast imaging with a CT mode, multiple tomosynthesis modes, and a mammography mode
US9811758Jun 19, 2015Nov 7, 2017Hologic, Inc.Matching geometry generation and display of mammograms and tomosynthesis
US20090001296 *Jun 29, 2007Jan 1, 2009Kuduvalli Gopinath RIntegrated variable-aperture collimator and fixed-aperture collimator
US20090003519 *Nov 23, 2005Jan 1, 2009Kenneth DefreitasIntegrated Multi-Mode Mammography/Tomosynthesis X-Ray System And Method
US20090141859 *Dec 24, 2008Jun 4, 2009Hologic, Inc.Image Handling and Display in X-Ray Mammography and Tomosynthesis
US20100090120 *May 18, 2009Apr 15, 2010Cnr Consiglio Regionale Delle RicercheScintigraphic device with spatial super-resolution
US20100091940 *Oct 6, 2009Apr 15, 2010Jasmina LudwigTomosynthesis apparatus and method to operate a tomosynthesis apparatus
US20110069809 *Nov 29, 2010Mar 24, 2011Hologic, Inc.Integrated multi-mode mammography/tomosynthesis x-ray system and method
DE102008050571A1 *Oct 6, 2008Apr 15, 2010Siemens AktiengesellschaftTomosynthesegerät und Verfahren zum Betrieb eines Tomosynthesegerätes
EP2602743A2Nov 15, 2005Jun 12, 2013Hologic, Inc.Matching geometry generation and display of mammograms and tomosynthesis images
EP3062093A4 *Oct 23, 2014Oct 18, 2017Nanovision Tech (Beijing) Co LtdPhoton count-based radiation imaging system, method, and apparatus
EP3106094A2Nov 23, 2005Dec 21, 2016Hologic, Inc.Integrated multi-mode mammography/tomosynthesis x-ray system
WO2009041803A2 *Sep 25, 2008Apr 2, 2009Mimos BerhadImage scanning device and method
WO2009041803A3 *Sep 25, 2008Jun 25, 2009Hock Woon HonImage scanning device and method
Classifications
U.S. Classification378/147
International ClassificationG21K1/04
Cooperative ClassificationG21K1/04
European ClassificationG21K1/04