An investigation into the use of carbon fibre for megavoltage radiotherapy applications.

Properties of carbon fibre of relevance to its use for megavoltage radiotherapy applications have been investigated. Measurements have been made of the percentage transmission and percentage build-up of carbon fibre at energies of 5, 6 and 8 MV. The results are presented in comparison with those obtained for other materials commonly used in radiotherapy: polymethylmethacrylate (PMMA), PETG copolyester and expanded polystyrene foam. It was found that carbon fibre has a higher percentage transmission and a lower percentage build-up than either PMMA or PETG copolyester. It was also found that the build-up due to a combination of carbon fibre and 5 cm of polystyrene foam was less than 65% over the energy range for which measurements were made, and much lower than that due to PETG copolyester. It is thus proposed that carbon fibre is a suitable material from which to make devices for use in megavoltage radiotherapy.