Dose Validation of GRID Block Treatment Applicator within the RayStation Treatment Planning System

TL;DR

This paper presents the first implementation and validation of GRID therapy protocols within RayStation TPS, including dose validation and a standardized clinical approach using the GRID block applicator.

Contribution

First to implement and validate GRID therapy protocols in RayStation TPS, introducing a novel standardization method for clinical application.

Findings

Achieved 98% dose agreement between planned and delivered doses.

Developed a robust dose validation method using dosimetry data and Mapcheck2.

Proposed a standardized approach for GRID block implementation in RayStation.

Abstract

Spatially Fractionated Radiation Therapy (SFRT) or GRID therapy has been in existence for more than a century. GRID therapy was invented as an approach to address the challenges posed by bulky tumors. To treat patients with GRID therapy, the protocol needs to be implemented within the Treatment Planning System (TPS) software. Also, the dose needed for treatment must be validated. A few TPS software vendors such as Elekta and Varian have protocols for treating patients with GRID therapy. However, we are the first to implement the protocols within RayStation TPS. To achieve these, we used the .decimal GRID block applicator to create conformal treatment plans. For the beam modeling, several dosimetry data, and measurements such as percentage depth dose (PDD), beam profile, output, and GRID factors, were obtained for different field sizes and energies. The dose distribution from the GRID openings covered the Planning Target Volume (PTV), with the QA plan having a 98% agreement with the planned dose. Also, we used the Mapcheck2 results to verify the adjustments made to the script variables such as aperture size (hole and spacing). We developed a robust way to validate the dose needed for patient treatment using the GRID block applicator. Also, we have proposed a novel approach to standardize the clinical implementation of the GRID block in RayStation TPS.