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A comparison of singlet oxygen explicit dosimetry (SOED) and singlet oxygen luminescence dosimetry (SOLD) for photofrin-mediated photodynamic therapy

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posted on 2023-06-09, 13:35 authored by Michele Kim, Rozhin Penjweini, Nathan R Gemmell, Israel Veilleux, Aongus McCarthy, Gerald Buller, Robert Hadfield, Brian Wilson, Timothy Zhu
Accurate photodynamic therapy (PDT) dosimetry is critical for the use of PDT in the treatment of malignant and nonmalignant localized diseases. A singlet oxygen explicit dosimetry (SOED) model has been developed for in vivo purposes. It involves the measurement of the key components in PDT—light fluence (rate), photosensitizer concentration, and ground-state oxygen concentration ([3O2])—to calculate the amount of reacted singlet oxygen ([1O2]rx), the main cytotoxic component in type II PDT. Experiments were performed in phantoms with the photosensitizer Photofrin and in solution using phosphorescence-based singlet oxygen luminescence dosimetry (SOLD) to validate the SOED model. Oxygen concentration and photosensitizer photobleaching versus time were measured during PDT, along with direct SOLD measurements of singlet oxygen and triplet state lifetime (t? and tt), for various photosensitizer concentrations to determine necessary photophysical parameters. SOLD-determined cumulative [1O2]rx was compared to SOED-calculated [1O2]rx for various photosensitizer concentrations to show a clear correlation between the two methods. This illustrates that explicit dosimetry can be used when phosphorescence-based dosimetry is not feasible. Using SOED modeling, we have also shown evidence that SOLD-measured [1O2]rx using a 523 nm pulsed laser can be used to correlate to singlet oxygen generated by a 630 nm laser during a clinical malignant pleural mesothelioma (MPM) PDT protocol by using a conversion formula

History

Publication status

  • Published

File Version

  • Published version

Journal

Cancers

ISSN

2072-6694

Publisher

MDPI

Issue

12

Volume

8

Page range

109

Department affiliated with

  • Engineering and Design Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2018-05-30

First Open Access (FOA) Date

2018-05-30

First Compliant Deposit (FCD) Date

2018-05-30

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