The radiation therapy of the future adjusts itself to the patient

Together with physicians, other research groups, and industry partners, Fraunhofer MEVIS is developing software to optimize radiation therapy. The fifth clinical workshop to evaluate this software took place in Bremen on February 5 and 6, 2015.

Radiation therapy for cancer usually lasts for several weeks. During this time, the situation of the patient changes: bodyweight decreases, causing the tumor to shrink or change shape. As a result, the initial distribution of the radiation dose is no longer optimal. In the worst case, the radiation can no longer fully hit the tumor, causing part of the radiation to reach and damage healthy tissue.

To avoid this, doctors have to adjust the direction and dose of the radiation according to current conditions. Until now, this replanning has been a costly and time-consuming procedure. The software developed in the BMBF-funded (Federal Ministry of Education and Research) SPARTA project aims at speeding up the process. Fraunhofer Institute for Medical Image Computing MEVIS has contributed a fast and accurate method of transferring the original planning situation to the current patient condition.

At the beginning of every radiation therapy, doctors develop a detailed treatment plan based on CT imagery. This plan indicates the body areas that must be irradiated, as well as how often and with what dosage they must be treated. The goal is to completely destroy the tumor while sparing nearby tissue. This cannot be done with a single radiation session. Patients might undergo daily therapy for a month to successfully fight the cancer.

“To ensure that the tumor is targeted as planned, doctors take routine control images of the patient,” said MEVIS researcher Stefan Wirtz. “That way, they can also recognize whether the patient is lying accurately in the device.”

To adjust the radiation optimally, doctors must compare the original planning images with the most recent control images. “Often, the doctor must view old and new images and compare them mentally,” Stefan Wirtz said.

“Our software can align both of them in a single image and transfer the contours of the radiation area.” As a result, doctors can quickly recognize whether the original contours still apply to the current situation. If not, the contours can easily be adjusted with the software tools. “Until now, replanning radiation therapy could take several hours,” said Stefan Kraß. “Our software can accelerate the process considerably.”

To make the software user-friendly, MEVIS exchanged ideas with radiation therapists several times a year and discussed progress during joint workshops. “When the project ends in March 2016, we want to present software that is by and large ready for practical use,” said Stefan Kraß, “and the software maturity achieved through close clinical collaboration might motivate the industry to want to market these results and address the necessary certification.”

The SPARTA project (Software Platform for Adaptive Multimodal Radio and Particle Therapy with Autarkic Extendibility) is funded by the German Federal Ministry of Education and Research (BMBF). It started on April 1, 2013 and will run for three years. The consortium encompasses ten partners, including research institutes, medical technology companies, and university clinics.

 

Fraunhofer MEVIS

www.mevis.fraunhofer