Diffuse Correlation Spectroscopy (DCS) and Diffuse Optical Spectroscopy (DOS) for photodynamic therapy monitoring.

• Main Author: Siti Raudhah Matyasir.
• Other Authors: Lee Kijoon
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Bioengineering
• Online Access: http://hdl.handle.net/10356/53684
• Institution: Nanyang Technological University

Photodynamic Therapy (PDT), is a cancer therapy that is still on clinical trial, is used in this project. PDT is an emerging modality that has many advantages such as non-invasive, low side effects, low scarring, low risk of resistance, cost effective and shorter treatment time. The aim is to evaluate the relative tissue oxygen saturation (rStO2) and relative blood flow (rBF) of the tumour-bearing mice obtained from Diffuse Optical Spectroscopy (DOS) and Diffuse Correlation Spectroscopy (DCS) respectively in order to see if they have prognostic value in predicting tumour response. Ce6 (Chlorin-6 trisodium salt) is the photosensitizer used in this experiment. Other parameters used are illumination time, light dose of PDT and fluence rate. Almost all mice went through photodynamic therapy at least twice. Three types of tumour response are identified after photodynamic therapy; a complete responder, partial responder and non-responder. A complete responder is an excellent response towards the treatment with the tumour almost more than 50% destroyed and it correlates with the decreasing rStO2 and rBF 1 hour after PDT until 2 days post PDT. Non-responder has no effect from the therapy with any reduction of tumour volume. Partial responder has its tumour reduced less than 50% or a regrowth subsequently after therapy therefore both rStO2 and rBF might decrease but increase back starting from 3 hours post PDT. Predictions can be made about photodynamic therapy efficacy; the average value for rBF below 0.5 at 3 hours post PDT is considered to be responder while above 0.5 is considered to be non-responder. The area under the ROC curve is 0.91 proved that the threshold of 0.5 of rBF is trustworthy. Finally, limitations were found and recommendations were proposed to further optimize the therapy outcomes.