Design and manufacture of a high precision personalized electron bolus device for radiation therapy

Abstract

This paper investigates a novel design and manufacturing methodology for an unmet need in radiation therapy—dose optimization of electron beam bolus. A thin-walled bolus design was proposed which when filled with water, optimized the dose distribution for the electron beam radiation therapy. The fabrication of this design was accomplished by the fused deposition modelling (FDM) additive manufacturing (3D Printing) technique. Acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) materials were employed for fabricating the electron boluses. Our data show that both the materials displayed expected radiation modulation. The designed boluses were subjected to higher radiation doses (50 Gy) and revealed permissible deformations based on the dimensional deviation analysis. Mechanical deformation tests were performed to evaluate the bolus design and materials under different loading conditions. The results showed that the ABS material had superior mechanical strength and deformation behaviour as compared to PC. Finite element analysis of the bolus designs revealed regions of stress concentration and potential failure modes which were validated by experimental results. The design of experiments analysis showed that bolus thickness and material type had a profound influence on the mechanical deformation of the bolus. The proposed radiation device technology is cost-effective, eco-friendly and amenable to changes in the tumour size and shape, compared to current methods. This paper provides a framework for the design and manufacture of radiation modulation devices that can be implemented for proton, electron and photon cancer therapies.