Preserving memory function in whole-brain radiation Therapy: Efficacy of HyperArc and Coplanar VMAT techniques

Preserving memory function in whole-brain radiationTherapy: Efficacy of HyperArc and Coplanar VMAT techniques Recent studies have assessed the practicality of adhering to RTOG 0933 dose limits via Volumetric Modulated Arc Therapy (VMAT), incorporating both coplanar and non-coplanar beam configurations (5)(6)(7) .IMRT and VMAT techniques allow precise targeting of tumours while minimizing radiation dose to critical structures like the hippocampus.These techniques offer improved control over the dose distribution, reducing the risk of radiation-induced da mage.Varian Medical Systems has developed HyperArc, a specialized approach for planning and treating intracranial lesions.HyperArc simplifies planning by autonomously choosing the best isocenter and collimator angles while also implementing non-coplanar arc configurations.It aims to achieve precise treatment delivery while minimizing radiation exposure to surrounding healthy tissue (8) .HyperArc utilizes a combination of up to four arcs, including one full coplanar arc and thre e partial non-coplanar arcs, and employs conventional positioning aids to ensure collision prevention (9) .The primary difference in planning lies between standard VMAT techniques and HyperArc, A dditionally, HyperArc enhances delivery efficiency through seamless couch transitions between successive treatment arcs (10,11) .However, this technique led to extended planning a n d treatment times due to multiple non-coplanar beams.The crucial roles of collimator angles and multileaf-collimator (MLC) thickness in optimizing