Digital Pathology Blog

New technology with host of photonic applications

A research team led by a chemist at the University of California, Riverside has fabricated microscopic polymer beads that change color instantly and reversibly when external magnetic fields acting upon the microspheres change orientation.

Applications of the new material include display type units such as rewritable or reusable signage, posters, papers and labels, and other magnetically activated security features, as well as environmentally friendly pigments for paints and cosmetics, and ink materials for color printing.

More information at:

http://www.eurekalert.org/pub_releases/2009-06/uoc--nfm061609.php

http://newsroom.ucr.edu/news_item.html?action=page&id=2124

Raman Molecular Imaging For Digital Pathology

The use of digital pathology techniques without stains or reagents is gaining traction for use in clinical practice, particularly for "gray" diagnostic areas where tride-and-true physical stains and or chemicals may not provide high enough specificity for diagnosis.  I have been following the work being done by ChemImage and their clinical projects with some exciting results.  Check out their offerings and results with Raman and hyperspectral imaging.

Accurate interpretation of pathology specimens can be very challenging for a number of tissue and disease types. Traditional pathological evaluation of tissues and cells is a relatively subjective evaluation of spatially complex stained tissue samples. Since a physician makes treatment decisions based on the evaluation of tissue by a pathologist, accuracy is of the utmost importance.

ChemImage’s Raman Molecular Imaging (RMI) approach using the FALCON II™ enables the objective assessment of tissues without the use of stains or reagents.

              

H&E Stained Prostate Tissue         Raman Image of Unstained Prostate Tissue

(Performed in collaboration with the Mayo Clinic and Allegheny General Hospital)

Raman Molecular Imaging Gives Pathologists:

• Molecular specificity
• Sensitivity to subtle molecular differences
• Measurement of Raman signals from the molecular constituents of a sample without reagents
• Measurements that are spatially localized within a given sample

Raman molecular images are acquired from tissue samples illuminated by a laser in a microscope. The images are analyzed using chemometric-based classification algorithms to objectively classify the sample in terms of disease state. RMI is used to create, in effect, a digital stain of tissues and cells—without the use of reagents.

Related Information

FALCON II™ Wide-Field Raman Chemical Imaging System:
The FALCON II employs high throughput Multi-Conjugate Filters (MCF) and electron-multiplied Charge-Coupled Device (CCD) cameras for Wide-field Hyperspectral Imaging.
Learn More

Application Overview:
Anatomic Pathology Application Overview (PDF 835 KB)

Anatomic Pathology Posters:
Raman Molecular Imaging: A Tool For Investigating Biological Systems (PDF 318 KB)

Hyperspectral Fluorescence Bioimaging (PDF 1 MB)

Diagnostic Utility of Raman Molecular Imaging (RMI) in Separating Renal Oncocytoma from Chromophobe Renal Cell Carcinoma (PDF 697 KB)

Raman Spectroscopy To Predict Prostate Cancer Death After Radical Retropubic Prostatectomy (PDF 359 KB)

Leading-edge Laser Microdissection Technology

With thanks to Dr. Karl Robstad, a pathology resident in Albany, New York for the tip on this offering from Leica.

The new Leica LMD7000 is a laser microdissection system with a power-adjustable, high precision laser. For the first time, high laser power and high repetition rates, are combined within one system.

The laser’s high pulse repetition rates are ideal for the fast excision of single cells, cell clusters, or thin and soft samples. Additionally, high laser power allows the dissection of thick or hard specimens.

Both new Leica LMD6500 and LMD7000 laser microdissection systems use gravity to gently collect the samples. The dissected material, whatever its size or shape, is collected in a contact-free, contamination-free manner. No additional procedures are necessary for collection.

The laser beam movement of the Leica LMD7000 and LMD6500 is controlled by high precision optics, whereas the microscope stage and the sample are both fixed. This allows precise cutting accuracy at high magnifications, as well as high cutting speed at low magnifications. Both are prerequisites to obtain homogeneous material for downstream analysis and reliable results.

Leica Microsystems’ new intuitive user interface eases everyday research. Additional consumables, such as a non-fluorescent, glass-like membrane for all contrast methods, complete the extensive consumables program.

The new Leica LMD7000 and Leica LMD6500 laser microdissection systems are the ideal instruments to dissect live cells, single cells, and specific cell clusters for biomarker research, molecular pathology, and many more applications.

Top 10 Medical Innovations for 2009

For the third year in a row, Cleveland Clinic doctors and consultants have picked the medical innovations they think will rise to the top next year.

The Top 10 Medical Innovations for 2009 were announced on the closing day of the Clinic's sixth annual Medical Innovation Summit. 

Of particular interest to me is #4 - the use of multispectral imaging in pathology.  This is an active area of research in surgical pathology at many academic institutions.  These technologies offer the ability for increased throughput as well as enhanced diagnostic accuracy with the ability visualize directly numerous markers simultaneously.  With the use of spectal unmixing pathologists can not only discern what markers are expressed (i.e. presence of absence of a specific protein or cellular constituent) but to what degree or quantity they are present and perhaps most importantly the relationship of those proteins in a single cell. As opposed to looking at 4 different slides with 4 different stains and looking at tumor morphology this technology allows you to look at multiple stains on a single slide and analyze cellular morphology. 

One of the leading surgical pathologists in this field is Dr. Michael Feldman from the University of Pennsylvania.  He has lectured and written extensively on this subject.  His talk "Beyond Morphology" presented at the CAP Futurescape 2007 provides a nice review on the subject and the work he and his colleagues at CRI, Inc., one of the leading commercial manufacturers of systems and applications for this type of technology. 

Additional work by Dr. Feldman and others for specific types of cancers in-vitro as well as in-vivo with spectral and other light technologies justifies the placement of this technology as #4 on this list of medical innovations for 2009 and given the implication could be one of the most significant in surgical pathology in a decade.

Top 10 Medical Innovations for 2009

10. A national health information exchange. A comprehensive system of electronic health records that are portable and link consumers, doctors, hospitals and other health services providers. This computerized system has the potential to replace paper medical files with digital records that could increase quality of medical care and reduce its cost.

9. Doppler-guided uterine artery occlusion. An experimental procedure that uses sound waves and a clamp to kill fibroid tumors in the uterus. This procedure, which is being tested at the Clinic among other hospitals, could be an alternative to uterus removal for some women.

8. Integration of diffusion tensor imaging. A noninvasive technology that allows neuroscientists to create two- and three-dimensional, color images of the brain. Scientists use the images to locate nerve fiber bundles that must be preserved during brain surgery.

7. LESS and NOTES applications. Laparoendoscopic single-site surgery pairs minimally invasive surgical techniques with a single incision in the patient's belly button. Natural orifice transluminal endoscopic surgery is incision-less surgery through a natural orifice, such as the mouth, vagina or colon. Both techniques reduce infection rates and pain, and speed healing among patients.

6. New strategies for creating vaccines for avian flu. Scientists are working to engineer effective vaccines against killer bird viruses, such as H5N1. Current vaccines are formulated to match the flu virus as it mutates. A new approach uses a mock version of the virus to trigger an immune response that protects a person from the virus.

5. Percutaneous mitral valve regurgitation repair. Repairing a leaky mitral valve in the heart -- the one-way valve that connects the left atrium to the left ventricle -- from the inside out. A special clip is threaded through a catheter in the femoral artery in the groin to the heart. The clip is clamped on the center of the mitral valve "leaflets," holding them together and restoring normal blood flow.

4. Multispectral imaging systems . A time- and money-saving imaging system that when attached to a standard microscope enables pathologists to see up to four stained proteins at a time. Pathologists look at protein distributions to understand tumors and other abnormal tissues. Now, scientists must look at one of these proteins at a time.

3. Diaphragm pacing system. An electric device that stimulates the diaphragm to contract and relax, enabling paralyzed patients to breathe without the help of bulky mechanical ventilators. These devices can help paraplegics lead more normal lives and reduce rates of ventilator-induced pneumonia, which kills half of the people who get it. Synapse Biomedical Inc. in Oberlin makes a diaphragm pacing device called NeuRx DPS.

2. Warm organ perfusion device. Developed in Europe and being tested in the United States, this device pumps warm blood through a donor heart. The heart naturally starts beating and continues to beat until it is transplanted. This action keeps the heart from decaying.

1. Use of circulating tumor cell technology. A technology that measures tumor cells that circulate in the blood. Results can help doctors understand how a cancer is progressing and how to adjust treatments in patients who have repeat cancer.

Israel's ASI gives pathologists a vital second opinion

Check out this interesting story out of Israel using spectral imaging for improved diagnostics:

"You won't find many professionals in the field admitting it, but the awful truth is that pathology is not an exact science, and mistakes are made - too many mistakes, according to Limor Shiposh, CEO of Migdal Ha'emek's Applied Spectral Imaging (ASI).

That's why pathologists need a "second opinion," and ASI wants to help them, with a groundbreaking product that applies the techniques of advanced genetic study to the examination of cells for cancer or other diseases.

ASI, a privately held company founded in 1993, has been in the medical imaging business for over 12 years, pioneering the area of advanced imaging in cytogenetic research, the science of chromosomes and cell division.

ASI's highly acclaimed innovation in this area, SpectraCube, is a light-related spectral imaging platform technology used in a variety of the company's products. It allows researchers to distinguish between different materials on a chromosome by highlighting its features with unique colors, instead of the black dye that had been used previously."

Researchers develop imaging system with a precision 1,000 times sharper than existing techniques

The AFP (4/1) reports that researchers at the Stanford University School of Medicine "have perfected a new technique to magnify by more than 1,000 times molecules deep inside the human body, which may help detect minuscule tumors," according to a study published in the Proceedings of the National Academy of Sciences. Using "a phenomenon known as Raman spectroscopy," the researchers can "measure the way that the light hits the object and bounces off again." The resulting image features a scattering pattern, which is "known as a spectral fingerprint, and is unique to each kind of molecule, helping to determine a material's molecular composition and structure." While Raman spectroscopy is not new, the researchers "believe this is the first time the technique has been adapted to provide images from inside the human body," and it "could prove useful in surgery for removing cancerous tissue." New Scientist (4/1, Palmer) also covers the story.

Near-infrared light may help detect microscopic signs of Alzheimer's disease in brain tissue

        The UPI (3/18) reports that "[n]ear-infrared light may help detect microscopic signs of Alzheimer's disease in brain tissue," according to a study published in the journal Optics Letters. Researchers from the U.S. Department of Veterans Affairs Research "showed that as the microscopic plaques associated with Alzheimer's disease accumulate, the optical properties of the brain change and can be detected."

        Data indicate 18 percent of baby boomers may develop dementia USA Today (3/18, 6D, Fackelmann) reports that approximately "14 million, or roughly 18 percent, of the USA's 79 million baby boomers can expect to develop Alzheimer's or some other form of dementia in their lifetime," according to the report, 2008 Alzheimer's Disease Facts and Figures, which also "states that one out of eight boomers will be diagnosed with Alzheimer's, the most common type of dementia, at some point." Should no cure for Alzheimer's be found, the U.S. "will be faced with a half-million new cases of Alzheimer's in 2010, and nearly a million a year by the middle of the century." As baby boomers ago, "[t]he coming Alzheimer's epidemic will, if left unchecked, put a huge strain on the healthcare system, including Medicare," experts warn.

Superior phase contrast without special objectives

High resolution phase contrast and fluorescence imaging is now possible using the same objective, thanks to the unique external phase contrast system on Nikon's new Ti Series of inverted microscopes

The external phase contrast system, available on all models, locates the phase ring within the main microscope body thus allows for the use of high NA and Tirf objectives, for the acquisition of high quality phase contrast images. The Ti Series exclusive use of high NA objectives without phase rings to achieve phase contrast, enables the capture of brighter fluorescence images; essentially recapturing the 10-15% of light traditionally blocked out by the phase annulus in the objective.

This article was originally published on Laboratorytalk on 14 December 2007 at 8.00am (UK)

Related stories

Ti scope is central resource for live cell imaging
Claiming faster acquisition times and unparalleled accuracy, the Ti platform has been designed in collaboration with industry-leading cell biologists to provie a versatile new tool

Seven contrast techniques from a single microscope
Bringing together Nikon's well-known CFI 60 andCFI LU60 infinity optics, the LV-UDM has a truly modular design which allows seven different contrast techniques to be selected

In addition, the external phase contrast unit minimises both aberration and double image acquisition to achieve crisp definition of cells.

Commenting on the phase contrast capabilities of the Ti Series Alan Monk, biological imaging systems specialist for Nikon Instruments UK, said: 'The revolutionary design of this system will provide live cell researchers with a much higher level of image quality.

'Phase contrast images with less oblique shading than that of DIC observation can be achieved, allowing for high precision data processing and image analysis.

'As an example, individual cell contours will be able to be defined with a Tirf image specimen'.

Nikon's external phase contrast system is just one of the applications that places the Ti Series at the very heart of high magnification, high resolution live cell applications

Light bent the 'wrong' way

A new, easy-to-produce material created from semiconductors refracts light negatively, bending the waves in the opposite direction from that taken by all materials found in nature. This unique ability may contribute to significant advances in areas including high-speed communications and medical diagnostics.

The new substance is in a relatively new class of materials called "metamaterials," which are made out of traditional substances, such as metals or semiconductors, arranged in very small alternating patterns that modify their collective properties. This approach enables metamaterials to manipulate light in ways that cannot be accomplished by normal materials.

Previous metamaterials were two-dimensional arrangements of metals, which limited their usefulness. The Princeton University invention is the first 3-D metamaterial constructed entirely from semiconductors, the principal ingredient of microchips and optoelectronics.

"To be useful in a variety of devices, metamaterials need to be three-dimensional," said Princeton electrical engineering professor Claire Gmachl, one of the researchers on the study. "Furthermore, this is made from semiconductors, which are extremely functional materials. These are the things from which true applications are made."

The research team, led by engineering graduate student Anthony Hoffman, published its findings online Oct. 14 in the journal Nature Materials. Other Princeton researchers on the team include graduate students Leonid Alekseyev, Scott Howard and Kale Franz; former Council of Science and Technology fellow Dan Wasserman, now at the University of Massachusetts-Lowell; and former electrical engineering professor Evgenii Narimanov, now at Purdue University. The team also includes collaborators from Oregon State University and telecommunications firm Alcatel-Lucent.

Light waves and other forms of electromagnetic radiation bend whenever they pass from one medium to another. This phenomenon, called refraction, is readily observable when a straw placed into a glass of water appears to be bent or broken. Lenses in reading glasses or a camera work because of refraction. All materials have an index of refraction, which measures the degree and direction that light is bent as it passes through them. While materials found in nature have positive refractive indices, the material recently invented at Princeton has a negative index of refraction.

In the case of the straw in a glass, normal water would make the underwater portion of the straw appear to bend toward the surface. If water were able to refract light negatively, as the newly invented semiconductor does, the segment of straw under the water would appear as if it were bending away from the surface.

Far more than a neat optical illusion, negative refraction holds promise for the development of superior lenses. The positive refractive indices of normal materials necessitate the use of curved lenses, which inherently distort some of the light that passes through them, in telescopes and microscopes. Flat lenses made from materials that exhibit negative refraction could compensate for this aberration and enable far more powerful microscopes that can "see" things as small as molecules of DNA.

In addition, the new metamaterial is capable of negative refraction of light in the mid-infrared region, which is used in a wide range of sensing and communications applications. Its unique composition results in less lost light than previous metamaterials, which were made of extremely small arrangements of metal wires and rings. The semiconductors that constitute the new material are grown from crystals using common manufacturing techniques, making the metamaterial less complex, more reliable and easier to produce.

"Currently, the typical infrared lens is a massive object -- the setups are bulky," Hoffman said. "This new material may enable more compact mid-infrared optics because we now have a new material with an entirely new set of optical parameters in our toolkit."

The research is part of a multi-institutional research center called Mid-Infrared Technologies for Health and the Environment (MIRTHE). Researchers at MIRTHE are developing compact sensors that detect trace amounts of gases in the atmosphere and human breath. These could one day be used in devices that monitor air quality and enhance homeland security, as well as in noninvasive and on-the-spot medical tests for diabetes and lung disease.

The research relies on a new type of laser that emits mid-infrared light. Gmachl, who directs the MIRTHE project, said the new material could be used to make the lasers better and smaller. Next, the team plans to incorporate the new metamaterial into lasers. Additionally, the researchers will continue to modify the material in attempts to make features ever smaller in an effort to expand the range of light wavelengths they are able to manipulate.

The work was supported by the MIRTHE center and the Princeton Center for Complex Materials (PCCM), both sponsored by the National Science Foundation.