Assessing temperature increase during photodynamic therapy: a simulation model

• Published in: Journal of physics. Conference series 2021-03, Vol.1859 (1), p.12048
• Main Authors: Kareliotis, G, Kalkou, M, Tsigaridas, G, Makropoulou, M, Serafetinides, A A
• Format: Article
• Language: English
• Subjects: Body temperature; Hyperthermia; Ionizing radiation; Irradiance; Laser beams; Necrosis; Penetration depth; Photodynamic therapy; Physics; Spatial distribution; Temperature distribution; Temperature effects
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/1859/1/012048

Photodynamic therapy (PDT) is a non-invasive procedure mainly used for treatment of malignancies. It is based on cytotoxic products generation after the excitation of absorbed photosensitizing drugs by non-ionizing radiation. The wavelength chosen is usually in the 620 - 700 nm region, resulting in limited tissue penetration depth. The relatively low irradiance values and the treatment time that, in most cases, lasts for a few minutes result in limited photothermal effects, which are usually overlooked. Therefore, in this study we computationally assess the temperature distribution during PDT in a cancer bearing mouse model. A user-friendly application is created that could be used in the treatment planning step of PDT. It receives as input various parameters, such as laser power, beam radius, irradiation time, body temperature and returns the maximum tissue temperature and irradiance values. Furthermore, it offers visualization of the generated effects through the spatial distribution of temperature, irradiance, acute necrosis and damaged tissue percentage that are presented in the form of interactive 3D plots. The conducted simulations reveal that 43 °C, which are in the hyperthermia range, are difficult to be excessed in PDT clinical practice, although topical thermal effects are observed.