Terahertz rays, or T-rays, are safer than X-rays because they have one million times lower energy. Also, "Unlike X-rays, they can be focused to give sharper pictures," [Xi-Cheng Zhang] said. T-rays can also deliver more information than X-rays, such as a tumor's chemical composition. Every object yields a kind of signature reaction to the terahertz beam, so T-rays actually allow a technician to identify various substances. "The combination of information about both the physical and the biochemical nature of the cancer would be of particular value in diagnosis and choice of treatment options in breast cancer," Zhang said.
Other researchers, too, are interested in imaging techniques that allow a technician to peer into the depths of the cell. Molecular imaging, explained Sanjiv Sam Gambhir, director of the Crump Institute for Molecular Imaging at UCLA Medical School, is fundamentally changing the way biomedical researchers study cells. Gambhir hopes that molecular imaging will lead to the ability to detect cancer much earlier than currently feasible, when a tumor is just a small group of cancer cells.
As Umar Mahmood, radiology professor at Harvard Medical School and a research scientist at Massachusetts General Hospital's Center for Molecular Imaging Research in Charlestown, explained, progress in molecular imaging techniques is accompanying genomics-based drug development. These drugs act upon very specific cellular pathways, and new imaging techniques are needed to see if and how they work.