The application of high-dose grid radiotherapy technique

Abstract

High dose grid radiotherapy (GRID) refers to a single fraction of high-dose radiation (10-25 Gy) in which, beams are divided into multiple small beam lets through a grid collimator or MLC, resulting in non-uniform dose distribution of high and low dose area ( peak-to-valley effect) in the target volume. Recently, as 3D radiotherapy (3DRT) technology emerged, the 2D GRID has been reconfigured into 3D dose LATTICE whereby high doses are concentrated at each lattice vertex within the radiation target volume with drastically lower dose between vertices through multiple focused non-coplanar beams with different radiation techniques. Compared with 2D GRID therapy, 3D LATTICE shows significant effect on peak-to-valley and minimizes radiation to surrounding tissues.Experimental and clinical data have shown that LATTICE therapies can reduce toxicity to normal tissue while stimulating bystander effects, endothelial cell death and immunogenic abscopal effects leading to enhanced killing of tumor cells and further improve the control of the local and distant disease. The clinic experience with LATTICE, although limited, has demonstrated favorable outcomes, especially for treating bulky tumors and palliative intend. The exact mechanism of the clinical advantages by LATTICE is not explicitly known and a more comprehensive biological study and clinical trials are called should be carried out. Key words: High dose; Grid; Lattice; Bulky tumor; Hypofractionation