ATHENS, Ohio -- Research done at Ohio University will be used to help treat cancer patients with an experimental therapy that could replace traditional treatments for cancer, such as chemotherapy, gamma radiation and surgery.
The treatment, called boron neutron capture therapy, kills cancer tumors by breaking them up with neutrons, uncharged elementary particles found in the nuclei of atoms. Although the concept of neutron therapy isn't new, scientists so far haven't been successful in measuring the energy of neutrons with sufficient accuracy.
Work at Ohio University is solving that problem. Scientists here are producing neutrons and making precise measurements of their direction and speed in the university's Edwards Accelerator Lab -- one of only a handful of physics labs in the country capable of this kind of research.
The neutron measurements done in the lab will be used by Harvard Medical School physicians and Massachusetts Institute of Technology scientists to treat cancer patients in medical experiments beginning in April, says Steven Grimes, Ohio University professor of physics and astronomy and coordinator of the neutron measurement project.
"We're working in this collaborative effort with MIT and Harvard because we've got the technology to do this research and they've got the patients for the medical research," says Grimes, whose research on neutron measurements was published recently in the journal Nuclear Science and Engineering.
With current medical technology, most cancer patients are treated one of three ways: surgery, chemotherapy or radiation. But not all treatments are feasible in every situation, Grimes says.
Chemotherapy usually causes side effects, surgery isn't always viable and radiation often kills healthy tissue along with the cancerous tumor.
Researchers believe boron neutron capture therapy has few side effects. It is similar to traditional radiation but is less likely to destroy healthy tissue near the tumor, Grimes says. Researchers suspect the therapy is especially effective on small or irregularly shaped tumors.
During radiation, a beam of gamma rays hits a tumor and produces electrons that have a long path length, with electrons often traveling beyond the tumor and into healthy tissue. An electron is a different elementary particle than a neutron, with lighter mass and a negative charge.
In neutron therapy, a beam of neutrons is targeted at a tumor that has been injected with the chemical boron, a nonradioactive isotope. The neutrons cause the boron nuclei to split, releasing alpha particles that damage surrounding cells. The path length of alpha particles is the diameter of a few cells, much shorter than the path length of electrons. "Gamma rays often wander around in the healthy tissue," Grimes says. "Neutrons don't go very far once they hit matter."
Neutron beams used in these kinds of experiments are created with a machine called an accelerator. Ohio University's accelerator, which was built in 1968, speeds atomic particles to high energies -- up to 7 percent of the speed of light -- through a large dome charged to a high voltage by a moving belt.
What makes the university's accelerator unique are recent technological additions that allow it to measure the speed and number of neutrons with new levels of precision. In 1981, a 100-foot culvert was built into the side of a hill next to the university's accelerator laboratory. The culvert allows researchers to measure how long it takes neutrons to travel a certain distance.
Using this technology, researchers can determine the correct amount of neutrons and the speed of neutrons needed to treat certain types of cancers and tumors, Grimes says. For example, researchers would use a low-energy neutron beam to target a tumor close to the skin, while a high-energy beam would be used to target a malignancy deeper than 1 inch below the skin.
If neutron therapy experiments on cancer patients at Harvard and MIT are successful, Grimes says, hospitals may start purchasing accelerators similar to the one at Ohio University to begin treating patients. "We could play a large role in the development of this kind of cancer therapy," he says.
The research is supported by the U.S. Department of Energy. Grimes has published numerous papers on neutron research, including the article in Nuclear Science and Engineering, which was co-authored by John Anderson and Victor Madsen of the University of California Lawrence Livermore National Laboratory. Grimes holds an appointment in the College of Arts and Sciences.
Attention reporters and editors: The journal article on which this story is based is available by calling Melissa Rake at 740-593-1891 or Kim Walker at 740-593-1043.
Journal
Nuclear Science and Engineering