HERSHEY, Pa. -- To diagnose and treat diseases like cancer, scientists and doctors must understand how cells respond to different medical conditions and treatments. Researchers have developed a new way to study disease at the cellular level.

Dr. Keith Cheng, distinguished professor of pathology, pharmacology and biochemistry and molecular biology at Penn State College of Medicine, and a team of X-ray imaging physicists at the University of Chicago, have developed a new, 3D tissue imaging technique, called X-ray histotomography. The technique allows researchers to study the details of cells in a tissue sample without having to cut it into slices. And that could lead to better diagnosis and treatment for a variety of diseases, including cancer.

"The quantitative and objective measurements made possible by histotomography could potentially allow us to distinguish between subtypes of cancer and other diseases that presently look the same using traditional histology so that they may be more appropriately treated," Cheng said.
Traditional histology involves taking thin slices of tissues from patients, staining them, and examining them for irregular features under a microscope. Physical sectioning of the sample introduces tissue loss and distortion that leads to incomplete sampling and imperfect visualizations. According to researchers, X-ray histotomography avoids these problems and allows the three-dimensional features of cells like shape and volume to be measured accurately.

Over 10 years, Cheng and his team developed the technique by combining the principles of human computer tomography (CT) scanning and histology to image small organisms and tissues at a greater resolution in 3D.

"X-ray histotomography uses the same principles as a human CT scan," Cheng said. "CT involves shooting a series of X-rays of a subject, each at a slightly different angle. A computer program then uses the set of x-rays to create a 3D image."

The Cheng lab had previously used micro-CT, a smaller-scale version of human CT, to image small organisms and tissues. University of Chicago's Patrick La Rivière, associate professor of radiology, introduced Cheng to the use of a powerful x-ray source, the synchrotron, which allowed the research team to enhance their micro-CT scanning with increased resolution and faster imaging times. The synchrotron-based micro-CT might help pathologists someday answer questions like:

What are the individual characteristics of the disease the patient has? How many diseased cells are there? What are the individualized treatment options based on what I'm seeing?

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