Dosing by the Numbers
Model may simplify high-dose radiosurgery planning
There is no straightforward way to determine the optimal dose level and treatment schedules for high-dose radiation therapies such as stereotactic therapy, used to treat brain and lung cancer, or high-dose brachytherapy for treating prostate and other cancers.
However, radiation oncologists at the OSUCCC – James may have solved this problem by developing a mathematical model that encompasses all dose levels.
Typically, radiation therapy for cancer is given in daily low doses spread over many weeks. Oncologists often calculate the schedules for these fractionated, low-dose courses using a mathematical linear-quadratic (LQ) model that is also used to evaluate radiation response, interpret clinical data and guide clinical trials
“Unfortunately, the LQ Model doesn’t work well for high-dose radiation therapy,” says co-author Nina Mayr, MD, professor of Radiation Oncology. “Our study resolves this problem by modifying the current method to develop a Generalized LQ (gLQ) Model that covers all dose levels and schedules.”
First author, Jian Wang, PhD, who passed away unexpectedly in June 2010, was largely responsible for developing the gLQ Model.
If verified clinically, Mayr says, the gLQ Model could guide the planning of dose levels and schedules needed for the newer radiosurgery and stereotactic radiation therapy and for high-dose brachytherapy procedures that are increasingly used for cancer patients.
Mayr says the new model could allow oncologists to design radiation dose schedules more efficiently, help researchers conduct clinical trials for specific cancers more quickly, and make high-dose therapies available to cancer patients much sooner.
“Our Generalized LQ Model determines appropriate radiation levels across the entire wide spectrum of doses, from low to high, and from many to very few treatments, which is a new approach,” Mayr says.
Published in the journal Science Translational Medicine.