MATRIX METAL COLLIMATORS STUDIES FOR THE SPATIALLY FRACTIONATED RADIATION THERAPY. TUNGSTEN, TANTALUM AND IRON COLLIMATORS

Abstract

Radiation therapy has long been a cornerstone in cancer treatment, but its effectiveness is often limited by the need to
spare healthy tissues while targeting tumors. Spatially fractionated radiation therapy, a novel approach, addresses this challenge
by dividing the primary radiation beam into multiple minibeams, thereby increasing the peak-to-valley dose ratio (PVDR) and
potentially enhancing therapeutic outcomes. In this study, we explore the optimization of minibeam generation using
mechanical collimators composed of Tungsten, Tantalum, and Iron, three high-density materials well-suited for radiation
therapy applications. The primary objective of this research is to improve the efficiency of spatial dose fractionation, a critical
factor in reducing radiation-induced damage to normal tissues. The PVDR is a key parameter in fractionation, with a PVDR
of 8 or higher considered optimal. Minimizing the valley dose is equally crucial to preserve healthy tissue architecture and
support tissue repair. To achieve efficient spatial fractionation, we present a new type of metal matrix collimator with modular
design features, including 2.5 mm thick plates made of Tungsten, Tantalum, or Iron. These materials are chosen for their
hardness, facilitating mechanical processing, and reducing the need for post-processing. Central plates incorporate 1 mm wide
slits, creating channels for beam fractionation. A 5x5 hole matrix with 1 mm diameter and 2.5 mm pitch covers an area of
11x11 mm², providing flexibility in collimator size and geometry. Specialized collimator modules ensure alignment when
stacked.
This work introduces a novel metal matrix collimator design and presents promising results for improving spatial dose
fractionation in radiation therapy. Monte Carlo simulations provide insights into optimizing collimator features for maximum
efficiency. These findings support further biological studies to evaluate the impact of fractionation on both normal and tumor
tissues, paving the way for the practical implementation of collimation in clinical practice. Spatially fractionated radiation
therapy holds great promise as an alternative approach for treating complex cases in cancer therapy, potentially enhancing
patient outcomes and reducing radiation-induced side effects.