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Stringasci MD, Fortunato TC, Moriyama LT, Filho JDV, Bagnato VS, Kurachi C. Interstitial PDT using diffuser fiber-investigation in phantom and in vivo models. Lasers Med Sci 2017; 32:1009-1016. [PMID: 28474212 DOI: 10.1007/s10103-017-2225-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 04/27/2017] [Indexed: 11/30/2022]
Abstract
Photodynamic therapy (PDT) has been used for local treatment of several types of tumors. Light penetration of biological tissue is one limiting factor in PDT, decreasing the success rates of the treatment of invasive and solid tumors. In those cases, a possible solution is to use interstitial PDT, in which both diffuser optical fibers are inserted into the tumor. The uniformity of the diffuser emission plays a crucial role in planning the delivery of the appropriate light fluence and in ensuring treatment success. In this study, we characterized a diffuser optical fiber concerning its homogeneity. We showed that the diffuser emission can be inhomogeneous and that the necrosis generated by interstitial PDT using such a diffuser for illumination is asymmetrical in volume as a result. This observation has relevant consequences in achieving success in PDT and phototherapies in general, as the delivered light fluence depends on adequate previous knowledge of the irradiation profile.
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Affiliation(s)
- Mirian D Stringasci
- Sao Carlos Institute of Physics, University of São Paulo, Trabalhador Sao-Carlense Street, Number 400, São Carlos, São Paulo, CEP: 13566-590, Brazil.
| | - Thereza C Fortunato
- Sao Carlos Institute of Physics, University of São Paulo, Trabalhador Sao-Carlense Street, Number 400, São Carlos, São Paulo, CEP: 13566-590, Brazil
| | - Lilian T Moriyama
- Sao Carlos Institute of Physics, University of São Paulo, Trabalhador Sao-Carlense Street, Number 400, São Carlos, São Paulo, CEP: 13566-590, Brazil
| | - José Dirceu Vollet Filho
- Sao Carlos Institute of Physics, University of São Paulo, Trabalhador Sao-Carlense Street, Number 400, São Carlos, São Paulo, CEP: 13566-590, Brazil
| | - Vanderlei S Bagnato
- Sao Carlos Institute of Physics, University of São Paulo, Trabalhador Sao-Carlense Street, Number 400, São Carlos, São Paulo, CEP: 13566-590, Brazil
| | - Cristina Kurachi
- Sao Carlos Institute of Physics, University of São Paulo, Trabalhador Sao-Carlense Street, Number 400, São Carlos, São Paulo, CEP: 13566-590, Brazil
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Svanberg K, Bendsoe N, Axelsson J, Andersson-Engels S, Svanberg S. Photodynamic therapy: superficial and interstitial illumination. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:041502. [PMID: 20799780 DOI: 10.1117/1.3466579] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Photodynamic therapy (PDT) is reviewed using the treatment of skin tumors as an example of superficial lesions and prostate cancer as an example of deep-lying lesions requiring interstitial intervention. These two applications are among the most commonly studied in oncological PDT, and illustrate well the different challenges facing the two modalities of PDT-superficial and interstitial. They thus serve as good examples to illustrate the entire field of PDT in oncology. PDT is discussed based on the Lund University group's over 20 yr of experience in the field. In particular, the interplay between optical diagnostics and dosimetry and the delivery of the therapeutic light dose are highlighted. An interactive multiple-fiber interstitial procedure to deliver the required therapeutic dose based on the assessment of light fluence rate and sensitizer concentration and oxygen level throughout the tumor is presented.
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Lo WCY, Redmond K, Luu J, Chow P, Rose J, Lilge L. Hardware acceleration of a Monte Carlo simulation for photodynamic therapy [corrected] treatment planning. JOURNAL OF BIOMEDICAL OPTICS 2009; 14:014019. [PMID: 19256707 DOI: 10.1117/1.3080134] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Monte Carlo (MC) simulations are being used extensively in the field of medical biophysics, particularly for modeling light propagation in tissues. The high computation time for MC limits its use to solving only the forward solutions for a given source geometry, emission profile, and optical interaction coefficients of the tissue. However, applications such as photodynamic therapy treatment planning or image reconstruction in diffuse optical tomography require solving the inverse problem given a desired dose distribution or absorber distribution, respectively. A faster means for performing MC simulations would enable the use of MC-based models for accomplishing such tasks. To explore this possibility, a digital hardware implementation of a MC simulation based on the Monte Carlo for Multi-Layered media (MCML) software was implemented on a development platform with multiple field-programmable gate arrays (FPGAs). The hardware performed the MC simulation on average 80 times faster and was 45 times more energy efficient than the MCML software executed on a 3-GHz Intel Xeon processor. The resulting isofluence lines closely matched those produced by MCML in software, diverging by only less than 0.1 mm for fluence levels as low as 0.00001 cm(-2) in a skin model.
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Affiliation(s)
- William Chun Yip Lo
- University of Toronto, Department of Medical Biophysics, Rm. 8-324,610 University Avenue, Toronto, Ontario M5G 2M9 Canada
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Johansson A, Axelsson J, Andersson-Engels S, Swartling J. Realtime light dosimetry software tools for interstitial photodynamic therapy of the human prostate. Med Phys 2007; 34:4309-21. [DOI: 10.1118/1.2790585] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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