Advances

(Advances gives a glimpse of the many significant research projects at the university. Tell us about your discoveries by e-mailing: wisweek@news.wisc.edu.)

Program lends new precision to ‘gamma knife’ treatment
In treating brain tumors with radiation surgery, doctors must bombard the entire tumor while minimizing exposure outside the target and avoiding sensitive brain structures. The job must be done by analyzing scores of two-dimensional brain images and completed within 40 minutes, as the patient waits in an uncomfortable head frame.

In a promising new research effort, a mathematical program is helping automate and fine-tune this arduous process. Michael Ferris, UW–Madison computer scientist, is working with medical physicists and oncologists at the University of Maryland Medical School on a computer program to reduce the threat of human error in setting radiation treatment plans.

The team’s work is optimizing a technology called the “Gamma Knife,” a device designed exclusively for treating brain tumors. The Gamma Knife uses 201 radiation sources that combine simultaneously to create a “spherical ball” of treatment. About 200 Gamma Knife machines are in operation worldwide.

The computer program reduces the total number of doses needed for a completed treatment. Another major benefit of the computer program is speed. Since it is able to map out a treatment plan in 20 minutes or less, neurosurgeons can experiment with several alternative setups to find the most effective one.

The procedure also holds the promise of treating larger tumors, Ferris says. The Gamma Knife has been around since 1967 and was built by a Swedish medical company. But it has only come into its own recently as a brain surgery tool.

Team places sensors on iceberg
University researchers have placed Automatic Weather Stations on the massive Antarctic iceberg that broke away from the Ross Ice Shelf last March.

The iceberg, designated B-15A, is about 90 miles long and 20 miles wide.

Transported to the iceberg by the U.S. Coast Guard in late January, Jonathan Thom of UW–Madison and Douglas MacAyeal of the University of Chicago erected three stations on the ice surface, roughly 150 feet above the ocean.

The stations each incorporate Global Positioning System units that will allow the science team to track the motion of the berg; an anemometer to measure wind velocity and direction; and sensors to measure relative humidity, surface temperature and barometric pressure.

Two weeks worth of data from the sensors has already been collected by satellite. MacAyeal said he expects thatsoon he can begin analyzing the iceberg’s motion and the effects of collisions between the berg and the shoreline and ice at Cape Crozier in Antarctica.

The weather stations, assembled at UW–Madison, are equipped with batteries and solar panels. They could operate for up to five years.

Study: Low-phosphorus diet good for the environment
A recent field trial showed that reducing dietary phosphorus will reduce the total amount of phosphorus in dairy manure, and greatly reduce the amount of phosphorus that’s vulnerable to runoff, according to soil scientist Larry Bundy, soils graduate student Angela Ebeling and U.S. Department of Agriculture soil scientist Mark Powell.

Reducing dietary phosphorus by one-third reduced the amount of phosphorus in manure by one-half, according to Ebeling. It also reduced by a factor of four to five the amount of phosphorus that ran off from fields where the manure was applied. Phosphorus that runs off from land-applied manure encourages weed and algae growth in surface waters.