Engineers develop new prostate-cancer treatment plan
Doug Henderson (left) and Bruce Thomadsen are pursuing patents
on their method to speed treatment planning for prostate-cancer
n one method of treating prostate cancer, called brachytherapy, doctors
implant 50 to 100 radioactive iodine-125 or palladium-103 “seeds”
(pictured with the penny below), each just a few millimeters long,
in the gland to eradicate diseased tissue. To plan the seeds’
placement for maximum effectiveness and minimal damage to healthy tissue,
they map an ultrasound view of the prostate on a 3-D grid, and use optimization
software to calculate several sets of possible seed locations and determine
which configuration will work best.
| Radioactive seeds used
to treat prostate cancer
Inspired by a reactor physics technique called
adjoint—or “backward”—transport, Associate Professor
Henderson, Medical Physics Associate
Professor Bruce Thomadsen and graduate student Sua Yoo have developed
a method that could reduce the time of this treatment-planning step
from as long as 40 minutes to a couple of seconds. Using the adjoint
information, they assign a numerical rank to each possible seed location,
based on its potential to deliver radiation where it’s needed.
The greedy algorithm optimization software then computes the best seed
arrangement. This method also could make it easier for doctors to plan
treatments using combinations of seeds with varied characteristics.