1. Field of the Invention
This invention relates to microscopy, and particularly to simultaneously imaging multiple objects with a microscope array comprising a plurality of microscope optical imaging elements.
2. Description of the Prior Art
Microscopes have often been used to scan specimens of various kinds to obtain a plurality of microscopic images of all or a portion of the specimen. The specimens may be, for example, biological or biochemical samples, or inorganic mineral samples. Typical scanning microscopes operating in the visible spectrum have been discrete sequential imaging devices. In sequential imaging, a first object, or a portion of an object, is imaged and then moved out of the microscope's field of view, and a subsequent object, or portion of an object, is thereafter moved into the microscope's field of view and imaged, and so forth. Although sequential scanning can be used to obtain a plurality of discrete, two-dimensional microscopic images of an object which are thereafter stitched together to form a microscopic image of a larger portion of the object, such scanning is best suited for taking microscopic images of a plurality of independent objects sequentially where the image acquisition rate is not critical.
Recently, a type of scanning miniature microscope array, also known as an array microscope, has been developed for obtaining a microscopic image of all, or a large portion, of a relatively large object. This is done by scanning the object line-by-line in one direction with an array of optical elements having respective linear arrays of detectors distributed in a direction perpendicular to the scan direction. The data are captured digitally and mapped to their respective positions to produce a digital microscopic image representation of all or the large portion of the object. Ordinarily, the optical elements would have a large numerical aperture to produce high resolution, but a relatively small field of view and a relatively large image size. Thus, the elements selected to scan contiguous points along a given line must be offset in the direction perpendicular to the scan direction. The scanning array microscope permits faster data acquisition than a sequential, discrete scanning microscope and avoids having to stitch discrete two-dimensional images together, but is directed to obtaining a microscopic image of a single object or portion thereof.
A significant application of discrete sequential imaging is scanning of microarrays—a standard vehicle for biochemical analysis such as DNA testing, protein marking and the like—for which a large number of independent “cells” need to be imaged. A microarray is an aggregate of multiple cells disposed on a single substrate. The cells are used, for example, to observe chemical reactions or to test for specific gene sequences. Each cell contains some material that carries useful information that can be retrieved using suitable microscopy techniques, such as, for example, bright field microscopy, dark field microscopy and fluorescence microscopy. The cells are ordinarily arranged on a rectangular grid for ease of handling. The spacing of the cells can range from a few hundred micrometers to several millimeters. For example, experiments have been conducted with living cell cultures having a diameter on the order of 100 micrometers and a spacing of 250 micrometers. Scanning is accomplished by using mechanical or optical devices to advance the microscope or cell to the next sample location.
Microarrays are particularly suitable for discrete sequential scanning microscopy because of the independence of the cells; that is, they are independent objects for which respective two-dimensional images may be acquired in sequence. However, tests of a large volume of cells are typically needed for useful analysis, which makes it desirable to maximize the image acquisition rate so as to produce useful results in the minimum time and with minimum cost.
Accordingly, there is an unfulfilled need for methods and devices for increasing the data acquisition rate in imaging multiple objects, such as the cells of a microarray, so as to minimize the time for acquiring images of all of the objects.
The present invention meets the challenge of providing for simultaneous imaging of multiple independent objects by arranging the objects into an array, providing a microscope array having a plurality of imaging elements arranged in a corresponding array such that a plurality of the imaging elements may be optically aligned with respective independent objects, and simultaneously imaging the respective objects with the microscope array to produce respective discrete, two-dimensional images of the objects. All or a selected subset of the objects may be imaged simultaneously. Where only a subset of the objects is imaged simultaneously, sequential scanning of such subsets may be used to image a larger set of the objects to meet physical or cost constraints. Scanning may solely employ two-dimensional imaging object-by-object, or the objects may be individually and simultaneously scanned line-by-line by respective one-dimensional sub-arrays of detectors in one dimension as well.
Accordingly, it is a principle object of the present invention to provide a novel microscope array system for simultaneously imaging multiple objects. The foregoing and other objectives, features and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.
The present invention employs a microscope array having a plurality of microscope imaging elements arranged side-by-side. A microscope array has recently been developed wherein the imaging elements are arranged to image respective contiguous portions of a common object in one dimension while scanning the object line-by-line in the other dimension, in which case the microscope array is also known as an array microscope. Array microscopes may be used, for example, to scan and image entire tissue or fluid samples for use by pathologists. Individual imaging elements of array microscopes are closely packed, and have a high numerical aperture, which enables the capture of high-resolution microscopic images of the entire specimen in a short period of time by scanning the specimen with the array microscope. In the present invention a microscope array is used to image independent objects, or potions of a larger object, corresponding respectively to a plurality of microscope imaging elements in the array. While a high numerical aperture is desirable in some applications, close packing and scanning are not necessarily needed.
A first embodiment of a microscope array 10 adapted for use in the present invention is shown in
The microscope array 10 is typically provided with a detector interface 24 for connecting the microscope array to a data processor or computer 26 which controls the data acquisition process, and acquires and stores the image data produced by the detectors of devices 20. An object, or an array of objects such as a microarray, is placed on a stage 28 for simultaneous imaging of discrete areas of an object, or respective individual objects in an array of objects. Preferably the stage may be moved with respect to the microscope array, under control of the data processor, so as to image simultaneously selected subsets of objects, or portions of an object. The array may be equipped with a linear motor 30 for moving the imaging elements together axially to achieve focus, though individual axial focusing may also be provided.
The microscope array 10 also includes a trans-illumination system 7, which is shown as a plurality of individual illumination elements 13 for illuminating respective objects, or portions of a larger object, each having respective spaced-apart optical axes OA13. In this exemplary case elements 13 correspond one-to-one with the imaging elements 12, but single axis illumination may also be used. The illumination elements 12 may comprise a number of optical elements, such as the elements 15, 17 and 19. In this example, the elements 15 and 17 are lenses and the element 19 is a source of light, such as a light emitting diode. As for the imaging system, more or fewer optical elements may be employed to achieve desired illumination, as is well understood in the art. The optical elements of the illumination system may also be mounted on the support 22.
It is to be understood that epi-illumination may also be used with a microscope array according to the present invention. Also, the light sources may be integrated with the light detectors to achieve a desired image size and quality.
Turning to
The imaging array 38 may include any number of layers “L” of arrays of lenses or other optical elements such as polarizers, collimators, mirrors, and splitters. Three such layers L1, L2, and L3, are shown for purposes of illustration. The imaging array 38 defines N imaging elements 301, 302, . . . 30N for imaging, respectively, the N cells 36. Each imaging element defines a respective optical axis OA1, OA2, . . . OAN and has an associated field of view that encompasses the corresponding cell 36.
Also corresponding to the N cells 36 and the N imaging elements 30, the detector array 40 includes N detectors 401, 402, 403, . . . 40N for converting the images produced by the N imaging elements to associated electrical signals for input to the data processor for manipulation or video display. Where the amount of data accumulated during a single acquisition by the N detectors is significant, the data can be transferred into the processor while another microarray is being loaded.
It is an outstanding recognition of the present inventors that, since the objects, and therefore the cells, are discrete, they may be separated by any distances and yet still be imaged simultaneously with the microscope 32. Accordingly, there may be spaces, such as the spaces indicated as s1 and s2, between the cells, in contrast to the ordinary need in an array microscope to pack the imaging lens systems and detectors close together. A respective detector 40, imaging element 30, and cell 36 are all optically aligned to produce an image of a respective object 46 in the cell 36 on the detector 40 when the object is appropriately illuminated.
As an example of the operation of the imaging lens system to image the object 461 of the microarray, rays of light such as that referenced as “r” in
Scanning movements may be accomplished straightforwardly by moving the carrier 35 with respect to the imaging array 38 and the detector array 40, as shown by the example of
Turning to
Although the embodiments of
Any of the aforementioned microscope array embodiments 10, 32 and 42 may be employed as described above to image all N objects simultaneously. However, it may be necessary or desirable to divide the N objects into subsets and, while imaging simultaneously the objects in each subset, to image the subsets sequentially. This is necessary when there are fewer imaging elements and corresponding detectors than there are objects to be imaged, and may be desirable, for example, to lower the cost of the microscope array, or to meet physical constraints, such as the available size of the detectors.
Although there is no need for scanning where there is a one-to-one correspondence between objects to be imaged and imaging elements, and the detectors are themselves two-dimensional arrays, the relative positions of the microscope array and the object, or object array, must be changed sequentially where the number of imaging elements in the microscope array is less than the number of discrete object portions, or objects in an object array, to be imaged. This procedure is referred to herein as “stepping” the microscope array, wherein the controller 85 of
A microarray plate 34 for use with the detector array 44 is shown in
In this example, the detector 441 images the cell 36A11 in a first pass of the microscope array. The same detector is also used to image the remaining eight cells in the rectangle Q in respective subsequent passes. For example, the detector 441 may image the cells 36A11-36A33 in the following sequence: cell 36A12 in the second pass, and cell 36A13 in the third pass (corresponding to stepping three times in the negative “x” direction), thence to cell 36A23 in the fourth pass (corresponding to stepping once in the negative “y” direction), cell 36A22 in the fifth pass, 36A21 in the sixth pass, 36A31 in the seventh pass, 36A32 in the eighth pass, and 36A33 in the ninth pass, for a total of nine passes. Any other sequence may be used, though the order is preferably selected, such as that just described, to minimize the total stepping distance.
Where the detector array 34 is spatially periodic with a period G1 in the “x” direction and G2 in the “y” direction, the aforedescribed sequencing causes the detector 442 to image the objects in the cells defined by the grid element Q2, and causes the detector 443 to image the objects in the cells defined by the grid element Q3, and so on, to tile the microarray 34. Accordingly, the array comprising the cells 36A11, 36B11, 36C11, and 36D11 describes a first subset of the cells that is imaged on the first pass, the array comprising the cells 36A12, 36B12, 36C12, and 36D12 describes a second subset that is imaged on the aforedescribed second pass, and so on. It may be noted, by contrast with the subgroups discussed above, that the objects in the different subsets of
It may also be noted that within a given grid element Q, the array of cells 36 need not be spatially periodic, i.e., the cells 36 defined by a given grid element Q need not be centered on a regular grid pattern, provided all grid elements Q share the same pattern of cells, and the periodicity of the detector array 34 provides for stepping and repeating the patterns defined by the grid elements Q. Accordingly, for purposes herein, an “array” is any predetermined physical pattern and need not be regular or spatially periodic.
In the example of
It has been mentioned above that it is not generally necessary, and it may not be particularly desirable, to space the cells apart any particular distance in a microscope array for simultaneously scanning multiple objects according to the present invention. However, where methods are employed such as those just described that rely on making multiple passes, it is then desirable again to pack the objects close together to limit the travel of moving parts of the microscope required for each pass.
The embodiments described above make use of imaging and detector arrays that have spacings between imaging and detector elements that correspond to the spacings provided between the corresponding objects to be imaged, such as they may be arranged by the microarray plate 42. These spacings may be on a regular grid or be non-regular; however, it has been assumed that the imaging and detector elements corresponding to a particular object are physically aligned.
Alternatively, the invention may provide for altering either the actual or the virtual spacing between elements of the microscope to compensate for differences between these spacings and the corresponding spacings between objects. Turning to
Turning to
While a simple embodiment 60 of an array microscope has been provided to illustrate the concept, the array may be provided with dissimilar springs, to provide for dissimilar spacings between elements and therefore a distortion of the array 60, or the springs may be replaced with mechanical actuators, such as linear positioning actuators, to adjust the spacings between particular elements 62 as desired.
While some specific embodiments of an array microscope for simultaneously imaging multiple objects have been shown and described, other embodiments according with the principles of the invention may be used to the same or similar advantage. It should be noted that radiations other than visible light may be employed without departing from the principles of the invention.
The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, to exclude equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims that follow:
This application is a continuation application of U.S. Ser. No. 10/191,679, filed Jul. 8, 2002, entitled Microscope Array for Simultaneously Imaging Multiple Objects. This application is also a continuation-in-part application and claims the priority of U.S. Ser. No. 12/002,107, filed Dec. 14, 2007, entitled Large-Area Imaging by Concatenation with Array Microscope, which is a CIP of U.S. Ser. No. 11/711,283, filed Feb. 27, 2007, entitled Slide-Borne Imaging Instructions, which is a CIP of U.S. Ser. No. 10/637,486, filed Aug. 11, 2003, entitled Miniaturized Microscope Array Digital Slide Scanner, now U.S. Pat. No. 7,184,610, which is a continuation of PCT/US02/08286, filed Mar. 19, 2002, which claims the benefit of priority of U.S. Provisional Application No. 60/276,498, filed Mar. 19, 2001.
Number | Date | Country | |
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60276498 | Mar 2001 | US |
Number | Date | Country | |
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Parent | 10191679 | Jul 2002 | US |
Child | 12365779 | US | |
Parent | PCT/US02/08286 | Mar 2002 | US |
Child | 10637486 | US |
Number | Date | Country | |
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Parent | 12002107 | Dec 2007 | US |
Child | 10191679 | US | |
Parent | 11711283 | Feb 2007 | US |
Child | 12002107 | US | |
Parent | 10637486 | Aug 2003 | US |
Child | 11711283 | US |