Development of cylindrical diffusing fibres suitable for interstitial photodynamic therapy

Abstract

The development of suitable optical fibres, especially cylindrical diffusing fibres, has enabled the application of photodynamic therapy (PDT) in hollow organs such as the bronchus, oesophagus or the bladder. Although cylindrical diffusing fibres are commercially available, these are expensive and therefore many pre-clinical investigations are performed with institutionally-made fibres. We describe the production process of a plastic cylindrical diffusing fibre with good light distribution qualities and very low costs. To identify the permitted tolerances on fibre parameters, fibres with varying light distribution patterns were tested in an in vivo tumour model for growth delay after PDT. No significant difference in growth delay was found between these fibres using an energy of 100J cm⁻¹ at 24h after injection with Photofrin. These results indicate that by cheap, simple means, fibres can be made which are suitable for interstitial PDT and that small differences in light distribution patterns do not affect the in vivo response.