Image-guided radiotherapy developer ViewRay is touting a study on the value of its MRIdian system in delivering accelerated partial-breast irradiation (APBI).
The study, published in the November 2016 issue of the International Journal of Radiation Oncology, Biology, Physics, found that using the MRIdian system reduced planning target volumes (PTV), thereby reducing the amount of healthy tissue exposed to radiation.
Researchers from the Washington University School of Medicine in St. Louis evaluated 30 women with breast cancer (stages 0-I) who had previously undergone breast-conserving surgery and received APBI using the MRIdian system. The goal of the study was to determine intrafractional motion of the breast surgical cavity and assess delivered dose versus planned dose.
Results indicated there is minimal intrafractional motion and good agreement between delivered and planned dose (a mean difference of less than 1%). No additional margin was added for the MRIdian PTV, thereby reducing the PTV by 52%, compared with a 1-cm PTV margin that is used conventionally.
