Variable-motion optical tomography of small objects

• US 20030199758A1
• Filed: 04/19/2002
• Published: 10/23/2003
• Est. Priority Date: 04/19/2002
• Status: Active Grant

• Current Assignee: VisionGate, Inc.
• Original Assignee: VisionGate, Inc.
• Inventors: Nelson, Alan C.
• Granted Patent: US 7,197,355 B2
• Time in Patent Office: Days
• US Class Current: 600/425
• CPC Class Codes: G01N 15/1433 using image recognition
• CPC Class Codes: G01N 15/147 the analysis being performed on a sample stream
• CPC Class Codes: G01N 2015/1006 for cytology
• CPC Class Codes: G01N 2015/1027 Determining speed or velocity of a particle
• CPC Class Codes: G01N 2015/1445 Three-dimensional imaging, imaging in different image planes, e.g. under different angles or at different depths, e.g. by a relative motion of sample and detector, for instance by tomography
• CPC Class Codes: G01N 21/4795 spatially resolved investigating of object in scattering medium in vivo A61B
• CPC Class Codes: G01N 2201/0813 Arrangement of collimator tubes, glass or empty
• CPC Class Codes: G01N 2223/612 biological material
• CPC Class Codes: G06T 11/006 Inverse problem, transformation from projection-space into object-space, e.g. transform methods, back-projection, algebraic methods
• CPC Class Codes: G06T 2211/421 Filtered back projection [FBP]

Abstract

Motion of an object of interest, such as a cell, has a variable velocity that can be varied on a cell-by-cell basis. Cell velocity is controlled in one example by packing cells into a capillary tube, or any other linear substrate that provides optically equivalent 360 degree viewing access, so that the cells are stationary within the capillary tube, but the capillary tube is translated and rotated mechanically through a variable motion optical tomography reconstruction cylinder. The capillary tube motion may advantageously be controlled in a start-and-stop fashion and translated and rotated at any velocity for any motion interval, under the control of a computer program. As such, there are several configurations of the optical tomography system that take advantage of this controlled motion capability. Additionally, the use of polarization filters and phase plates to reduce light scatter and diffraction background noise is described.

Claims

1. A method for three dimensional (3D) reconstruction of an object of interest, comprising the steps of:

(a) packing objects of interest into a linear container;

(b) illuminating the object of interest with at least one optical projection beam;

(c) translating the linear container until an object of interest is located within a region of the at least one optical projection beam;

(d) centering the object of interest as necessary;

(e) rotating the object of interest through a plurality of radial angles;

(f) generating a set of projection images at each radial angle of the plurality of angles; and

(g) repeating the steps (b) through (f) until the objects of interest have been scanned.

2. The method of claim 1, wherein the object of interest is a cell or a cell nucleus.

3. The method of claim 1, wherein the step of packing objects of interest into a linear container comprises the steps packing a plurality of cells into a tube.

4. The method of claim 1 wherein the optical projection beam is selected from the group consisting of fan beam projections and cone beam projections.

5. A method for three dimensional (3D) reconstruction of an object of interest using a reconstruction cylinder design wherein a plane of point sources and a plane of detector elements are different but parallel, and wherein the reconstruction cylinder has an arrangement of sources and detectors around a circumference of a sample, the method comprising the steps of:

(a) packing objects of interest into a linear container;

(b) illuminating the object of interest with a plurality of optical projection beams;

(c) translating the linear container until an object of interest is located within a region of the plurality of optical projection beams;

(d) centering the object of interest as necessary;

(e) generating a set of projection images at a plurality of angles; and

(f) repeating the steps (b) through (e) until the objects of interest have been scanned.

6. A reconstruction cylinder comprising at least one point source and at least one detector positioned to receive information from the light source, wherein separate projections are created by rotating a sample in the reconstruction cylinder so that light from the at least one light source impinges on the sample forming a projected image on the at least one detector.

20. The system of claim 6 wherein at least two polarization filters are positioned between the at least one point source and at least one detector.

23. The system of claim 6 wherein at least one phase plate is positioned between the object and at least one detector.

7. A variable-motion optical tomography (VOT) system comprising:

a tube for holding objects of interest having a tube wall and a tube axis;

a plurality of optical point sources are arranged to project light around a circumference at the tube wall;

a plurality of opposing detector surfaces arranged on a wider circumference in the same plane as the point sources, to form a reconstruction zone, so that each point source projects a beam onto a detector area such that one beam does not overlap another on any of the plurality of opposing detector surfaces, and a central axis of each beam intersects the other beams central axes within the tube; and

means, coupled to the tube, for moving the tube in a variable motion.

8. The system of claim 7 wherein the means for moving comprises a computer controlled motion apparatus.

9. The system of claim 7 wherein the means for moving comprises a means for rotating the tube such that each time the tube is rotated by a rotation displacement value a set of projections is collected.

10. The system of claim 7 wherein the plurality of optical point sources comprises two or more point sources.

11. The system of claim 7 wherein a semicircle of spaced point sources have opposing detector arrays positioned around an opposite semicircle, the spaced point sources and the opposing detector arrays being positioned on the same central plane generally perpendicular to the tube axis.

12. The system of claim 7 wherein the plurality of optical point sources and the plurality of opposing detector surfaces lie in the same plane, and the plurality of optical point sources are interspersed between detector arrays.

13. The system of claim 7 wherein additional sets of optical point sources and detectors are positioned above and/or below the reconstruction zone to provide additional projection data.

21. The system of claim 7 wherein at least two polarization filters are positioned between the plurality of point sources and the plurality of opposing detector surfaces.

24. The system of claim 7 wherein at least one phase plate is positioned between the object and the plurality of opposing detector surfaces.

14. A variable-motion optical tomography (VOT) system comprising:

a tube for holding objects of interest; and

a ring of point sources in a plane where the plane is located proximately above or proximately below a ring of detectors located around a detector plane through the tube, such that the ring of point sources aim optical projection beams at opposing detector surfaces within a reconstruction zone, and the center of the cell is located between the two planes at a point where all optical projection beams overlap.

15. The system of claim 14 further comprising means for providing variable motion under computer control.

16. The system of claim 14 further comprising means for rotation of the tube.

17. The system of claim 14 wherein the optical projection beams comprise fan beam projections.

18. The system of claim 14 wherein the optical projection beams comprise cone beam projections.

19. The system of claim 14 wherein additional sets of sources and detectors are positioned above and/or below the reconstruction zone to provide additional projection data to the computed image reconstruction algorithm.

22. The system of claim 14 wherein at least two polarization filters are positioned between the ring of point sources and the opposing detector surfaces.

25. The system of claim 14 wherein at least one phase plate is positioned between the object and the opposing detector surfaces.

26. Any configuration of tomography system where the spaces between the at least one point source and the object and the spaces between the object and the at least one detector surface are filled with a material whose index of refraction is matched with that of the tube.