Under the skin : Monte Carlo radiation transfer modelling of photodynamic therapy

Photochemotherapy;Monte Carlo method

Campbell, Catherine Louise ; Wood, Kenny ; Wood, Kenny

University:University of St Andrews

Department:Physics & Astronomy (School of)

关键词: Photochemotherapy;    Monte Carlo method;   

Others  :  https://research-repository.st-andrews.ac.uk/bitstream/handle/10023/9899/CatherineCampbellPhDThesis.pdf?sequence=2&isAllowed=y

来源: DR-NTU

【 摘 要 】

Photodynamic therapy (PDT) is a non-invasive treatment method used for treating superficialskin lesions such as non-melanoma skin cancer (NMSC). The combination of light, a photo-sensitive molecule and oxygen results in selective tissue destruction. Even though PDT hasresulted in many successful treatment outcomes, the treatment parameters such as requiredlight dose and preferred light source have not yet been optimised. Since monitoring of thetreatment progress is limited to surface observations, it is difficult to observe what is happening under the surface of the skin.In this thesis, the development of complex numerical modelling techniques is consideredwith the aim of increasing the understanding of how PDT works within the living skin tis-sue. In particular, the potential of using daylight as an alternative therapeutic light source isexplored. Daylight PDT is associated with lower experienced pain and has the potential ofreducing pressure on the clinics as well as the number of treatment occasions.A Monte Carlo radiation transfer (MCRT) model was developed to track photon propagation during treatment. The first theoretical investigation of daylight PDT is presented wherethe results indicate a potential treatment depth of over 2 mm, which is sufficient for treatingsuperficial skin cancer lesions. Additional models are developed, which consider the druginteraction and the diffusion of the drug. To include different patient characteristics andmore detailed skin models, multi-layered tissue as well as complex three dimensional tumourtissues are included within the MCRT model framework.There is no such thing as a generic patient, making it difficult to generate standardisedtreatment protocols. The research performed in this thesis provides further insights into lightinteraction with skin tissue for different patient and treatment characteristics, which is a vitalstep towards achieving more individualised treatment regimes.