NRG Oncology Protocol Development Template for Radiation Therapy — Brain: SRS

The NRG Oncology template for the radiation section of a brain radiosurgery trial. Its example text asks for CT slices of 1.25 mm or less, strongly encourages MRI (contrast T1 and a 3D gradient-echo sequence) for target delineation, recommends fusing FDG-PET/CT when available, and asks that the fusion be done by a medical physicist and reviewed by the attending physician. Its plan-evaluation section defines the conformity index (CI, or R100%) as the prescription isodose volume ÷ PTV volume, R50% as the 50% prescription isodose volume ÷ target volume ("R50% defines dose falloff outside the target"), a heterogeneity index D5% ÷ D95%, and coverage as the PTV volume receiving the prescription dose ÷ PTV volume, and notes that criteria such as the CI should account for target size and treatment technology.

How an NRG trial would write the radiation section for brain radiosurgery — thin-slice CT, MRI sequences and fusion review.