Interstitial PDT using diffuser fiber—investigation in phantom and in vivo models

• Published in: Lasers in medical science Vol. 32; no. 5; pp. 1009 - 1016
• Main Authors: Stringasci, Mirian D., Fortunato, Thereza C., Moriyama, Lilian T., Filho, José Dirceu Vollet, Bagnato, Vanderlei S., Kurachi, Cristina
• Format: Journal Article
• Language: English
• Published: London Springer London 01.07.2017; Springer Nature B.V
• Subjects: Animals; Asymmetry; Cancer; Dentistry; Diffusers; Emission; Fiber optics; Fibers; Fluence; Homogeneity; Humans; Illumination; In vivo methods and tests; Irradiation; Lasers; Light penetration; Liver - pathology; Liver - radiation effects; Male; Medicine; Medicine & Public Health; Models, Biological; Necrosis; Optical Devices; Optical Fibers; Optics; Original Article; Penetration; Phantoms, Imaging; Photochemotherapy - methods; Photodynamic therapy; Photonics; Quantum Optics; Radiation; Rats, Wistar; Solid tumors; Tumors; Variability; Heterogeneous irradiation profile; Interstitial; Photodynamic therapy; Diffuser optical fiber; iPDT
• ISSN: 0268-8921; 1435-604X
• DOI: 10.1007/s10103-017-2225-7

Photodynamic therapy (PDT) has been used for local treatment of several types of tumors. Light penetration of biological tissue is one limiting factor in PDT, decreasing the success rates of the treatment of invasive and solid tumors. In those cases, a possible solution is to use interstitial PDT, in which both diffuser optical fibers are inserted into the tumor. The uniformity of the diffuser emission plays a crucial role in planning the delivery of the appropriate light fluence and in ensuring treatment success. In this study, we characterized a diffuser optical fiber concerning its homogeneity. We showed that the diffuser emission can be inhomogeneous and that the necrosis generated by interstitial PDT using such a diffuser for illumination is asymmetrical in volume as a result. This observation has relevant consequences in achieving success in PDT and phototherapies in general, as the delivered light fluence depends on adequate previous knowledge of the irradiation profile.