1 July 2008 Magnetic resonance imaging guidance for laser photothermal therapy
Author Affiliations +
J. of Biomedical Optics, 13(4), 044033 (2008). doi:10.1117/1.2960020
Temperature distribution is a crucial factor in determining the outcome of laser phototherapy in cancer treatment. Magnetic resonance imaging (MRI) is an ideal method for 3-D noninvasive temperature measurement. A 7.1-T MRI was used to determine laser-induced high thermal gradient temperature distribution of target tissue with high spatial resolution. Using a proton density phase shift method, thermal mapping is validated for in vivo thermal measurement with light-absorbing enhancement dye. Tissue-simulating phantom gels, biological tissues, and tumor-bearing animals were used in the experiments. An 805-nm laser was used to irradiate the samples, with laser power in the range of 1 to 3 W. A clear temperature distribution matrix within the target and surrounding tissue was obtained with a specially developed processing algorithm. The temperature mapping showed that the selective laser photothermal effect could result in temperature elevation in a range of 10 to 45°C. The temperature resolution of the measurement was about 0.37°C with 0.4-mm spatial resolution. The results of this study provide in vivo thermal information and future reference for optimizing laser dosage and dye concentration in cancer treatment.
Yichao Chen, Surya C. Gnyawali, Feng Wu, Hong Liu, Yasvir A. Tesiram, Andrew Abbott, Rheal A. Towner, Wei R. Chen, "Magnetic resonance imaging guidance for laser photothermal therapy," Journal of Biomedical Optics 13(4), 044033 (1 July 2008). http://dx.doi.org/10.1117/1.2960020

Magnetic resonance imaging

Temperature metrology

Laser therapeutics



Laser irradiation

Laser tissue interaction

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