Assessment of singlet oxygen dosimetry concepts in photodynamic therapy through computational modeling
| Autor: | Sofia Liossi, Mersini I. Makropoulou, Georgios Kareliotis |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Fibrosarcoma
medicine.medical_treatment Monte Carlo method Biophysics Analytical chemistry chemistry.chemical_element Photodynamic therapy 02 engineering and technology Dermatology 01 natural sciences Oxygen 010309 optics Mice chemistry.chemical_compound 0103 physical sciences medicine Animals Dosimetry Computer Simulation Pharmacology (medical) Hypoxia Oxygen supply Photosensitizing Agents Dose-Response Relationship Drug Singlet Oxygen Singlet oxygen Hemodynamics Blood flow Models Theoretical 021001 nanoscience & nanotechnology Drug Therapy Computer-Assisted Disease Models Animal Photochemotherapy Oncology chemistry Carcinoma Basal Cell High blood flow 0210 nano-technology Monte Carlo Method |
| Zdroj: | Photodiagnosis and Photodynamic Therapy. 21:224-233 |
| ISSN: | 1572-1000 |
| DOI: | 10.1016/j.pdpdt.2017.12.016 |
| Popis: | Background In photodynamic therapy (PDT) oxygen plays a vital role in killing tumor cells. Therefore oxygen dosimetry is being thoroughly studied. Methods Light distribution into tissue is modelled for radiation-induced fibrosarcoma (RIF) and nodular basal cell carcinoma (nBCC), in order to study the influence of blood flow on singlet oxygen concentration effectively leading to cell death ([ 1 O 2 ] rx ) from PDT, within this light distribution. This is achieved through initial oxygen supply rate ( g 0 ) and initial molecular oxygen concentration ([ 3 O 2 ] 0 ) calculations. Monte Carlo simulations and mathematical models are used for spatial and temporal distributions of [ 1 O 2 ] rx . Hypoxia conditions are simulated by minimizing [ 3 O 2 ] 0 and g 0 . Furthermore, an optimization algorithm is developed to calculate minimum initial molecular oxygen concentration needed ([ 3 O 2 ] 0,min ) for constant [ 1 O 2 ] rx , when blood flow changes. Results Our results validate that in initially well-oxygenated scenarios with normal blood flow maximum [ 1 O 2 ] rx values are significantly higher than corresponding values of hypoxic scenarios both for RIF and nBCC models, with maximum oxygen supply rate percentage variations being independent from g 0 . Moreover, [ 1 O 2 ] rx appears to be more affected by an increase of g 0 than of [ 3 O 2 ] 0 values. For low blood flow there is a linear relationship between [ 3 O 2 ] 0,min and g 0 , while for better oxygenated areas high blood flow reduces [ 3 O 2 ] 0,min needed in exponential manner. Conclusions Blood flow appears to be able to compensate for oxygen consumption. The developed optimization protocol on oxygen dosimetry offers a suitable combination of [ 3 O 2 ] 0,min and g 0 to achieve constant [ 1 O 2 ] rx, despite possible blood flow variations. |
| Databáze: | OpenAIRE |
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