A simple scoring ratio to index the conformity of radiosurgical treatment plans

TLDR

A conformity index quantifies how well a radiosurgical dose distribution matches the target volume’s size and shape. The study aims to develop a new conformity index that objectively scores radiosurgical plans and avoids false perfect scores, addressing the need for accurate conformity assessment. The authors reviewed and critiqued existing conformity indices, derived a new objective index, and evaluated it against five treatment plans alongside current methods.

Abstract

✓ A conformity index is a measure of how well the volume of a radiosurgical dose distribution conforms to the size and shape of a target volume. Because the success of radiosurgery is related to the extremely conformal irradiation of the target, an accurate method for describing this parameter is important. Existing conformity ratios and indices used in radiosurgery are reviewed and criticized. It will be demonstrated that previously proposed measurements of conformity can, under certain conditions, give false perfect scores. A new conformity index is derived that gives an objective score of conformity for a treatment plan and gives no false scores. An analysis of five different treatment plans is made using both the existing scoring methods and the new conformity index.