A joint Fermilab/SLAC publication

Shrinking the cost of zapping cancer

10/01/09

Dejan Trbojevic's work on one of the world's largest particle accelerators helped him think small.

Shrinking the cost of zapping cancer

Dejan Trbojevic's work on one of the world's largest particle accelerators helped him think small.

Building on knowledge gleaned as a physicist with the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, he designed a smaller, lighter system for bombarding cancerous tumors with subatomic particles, such as protons and heavy ions. This form of therapy is used to treat tumors near delicate areas, such as the brain, spine, and prostate gland, and to reduce radiation doses to healthy tissue, which is especially important in growing children.

"This design greatly reduces the cost, weight, and size of the particle-delivery system for cancer treatment facilities, and simplifies its operation," Trbojevic says. "That should make such facilities more economical to build and operate."

Unlike conventional radiation beams, which deposit energy as they travel through healthy tissue, particle beams made of protons or charged ions deposit most of their energy at the tumor. This results in more cancer-killing potential in fewer doses, and with less collateral damage (see "The power of proton therapy" in the December 2008 issue of symmetry.)

But particle therapy facilities are expensive, in large part due to the size and complexity of the system that delivers the beam. In one common design, the equipment that generates the beam and the magnets that steer and focus it are mounted on a steel gantry that rotates around the patient to pummel the tumor from different angles. Trbojevic's design uses smaller, lighter magnets, reducing the weight of the gantry 100-fold. Further, he says these magnets could be manufactured at Brookhaven. The lab has applied for a patent on the new design.

Karen McNulty Walsh

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