scholarly journals Continuous Low-Irradiance Photodynamic Therapy: A New Therapeutic Paradigm

2012 ◽  
Vol 10 (Suppl_2) ◽  
pp. S-14-S-17 ◽  
Author(s):  
Gary S. Rogers
Keyword(s):  
Photodynamic Therapy ◽  
Light Exposure ◽  
Light Therapy ◽  
Principal Factor ◽  
Tumor Control ◽  
Fluence Rate ◽  
Energy Delivery ◽  
Light Fluence ◽  
Home Based ◽  
Home Based Therapy

A principal factor in determining the biologic consequences of photodynamic therapy (PDT) is the light fluence rate. Preclinical and, more recently, clinical studies have focused on low-irradiance schemes, suggesting that prolonged light exposure, better known as CLIPT (continuous low-irradiance PDT), may improve tumor control while reducing morbidity. After a brief look at the origin of light therapy and photosensitizers, this article turns to the promising animal research supporting the use of low- and ultra-low fluence rate PDT, which serves as the basis of the ongoing CLIPT dosimetry trials for patients with chest wall progression of breast cancer. The future of CLIPT seems to be a home-based therapy using a portable, self-contained energy delivery system.

Photodynamic Therapy at Low-Light Fluence Rate: in vitro Assays on Colon Cancer Cells

2019 ◽  
Vol 25 (1) ◽  
pp. 1-6 ◽  
Author(s):  
J. A. Rodrigues ◽  
R. Amorim ◽  
M. F. Silva ◽  
F. Baltazar ◽  
R. F. Wolffenbuttel ◽  
...  
Keyword(s):  
Colon Cancer ◽  
Photodynamic Therapy ◽  
Cancer Cells ◽  
Fluence Rate ◽  
Colon Cancer Cells ◽  
Low Light ◽  
Light Fluence

The Effect of Light Fluence Rate in Photodynamic Therapy of Normal Rat Brain

1992 ◽  
Vol 132 (1) ◽  
pp. 120 ◽  
Author(s):  
Q. Chen ◽  
M. Chopp ◽  
M. O. Dereski ◽  
B. C. Wilson ◽  
M. S. Patterson ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Rat Brain ◽  
Fluence Rate ◽  
Light Fluence ◽  
Normal Rat ◽  
Effect Of Light

scholarly journals Measurement of Cyanine Dye Photobleaching in Photosensitizer Cyanine Dye Conjugates Could Help in Optimizing Light Dosimetry for Improved Photodynamic Therapy of Cancer

Molecules ◽  
2018 ◽  
Vol 23 (8) ◽  
pp. 1842 ◽  
Author(s):  
Nadine James ◽  
Ravindra Cheruku ◽  
Joseph Missert ◽  
Ulas Sunar ◽  
Ravindra Pandey
Keyword(s):  
Photodynamic Therapy ◽  
Fluorescence Imaging ◽  
Tumor Response ◽  
Cyanine Dye ◽  
Fluence Rate ◽  
Low Light ◽  
Light Dosimetry ◽  
Light Fluence ◽  
Photodynamic Therapy Of Cancer

Photodynamic therapy (PDT) of cancer is dependent on three primary components: photosensitizer (PS), light and oxygen. Because these components are interdependent and vary during the dynamic process of PDT, assessing PDT efficacy may not be trivial. Therefore, it has become necessary to develop pre-treatment planning, on-line monitoring and dosimetry strategies during PDT, which become more critical for two or more chromophore systems, for example, PS-CD (Photosensitizer-Cyanine dye) conjugates developed in our laboratory for fluorescence-imaging and PDT of cancer. In this study, we observed a significant impact of variable light dosimetry; (i) high light fluence and fluence rate (light dose: 135 J/cm2, fluence rate: 75 mW/cm2) and (ii) low light fluence and fluence rate (128 J/cm2 and 14 mW/cm2 and 128 J/cm2 and 7 mW/cm2) in photobleaching of the individual chromophores of PS-CD conjugates and their long-term tumor response. The fluorescence at the near-infrared (NIR) region of the PS-NIR fluorophore conjugate was assessed intermittently via fluorescence imaging. The loss of fluorescence, photobleaching, caused by singlet oxygen from the PS was mapped continuously during PDT. The tumor responses (BALB/c mice bearing Colon26 tumors) were assessed after PDT by measuring tumor sizes daily. Our results showed distinctive photobleaching kinetics rates between the PS and CD. Interestingly, compared to higher light fluence, the tumors exposed at low light fluence showed reduced photobleaching and enhanced long-term PDT efficacy. The presence of NIR fluorophore in PS-CD conjugates provides an opportunity of fluorescence imaging and monitoring the photobleaching rate of the CD moiety for large and deeply seated tumors and assessing PDT tumor response in real-time.

Photodynamic Therapy with 5-Aminolevulinic Acid Induces Apoptosis and Caspase Activation in Malignant T Cells

2001 ◽  
Vol 5 (1) ◽  
pp. 8-13 ◽  
Author(s):  
Faten Gad ◽  
Gilles Viau ◽  
Michele Bousbira ◽  
Richard Bertrand ◽  
Robert Bissonnette
Keyword(s):  
Photodynamic Therapy ◽  
Dna Fragmentation ◽  
Caspase 3 ◽  
Aminolevulinic Acid ◽  
Light Exposure ◽  
Red Light ◽  
Jurkat Cells ◽  
Caspase Activation ◽  
Light Fluence ◽  
Malignant T Cells

Background: Preliminary studies have suggested that photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA) can improve psoriasis and mycosis fungoides, two diseases where normal or malignant T cells play a central role. Objectives: To determine if ALA-PDT induces apoptosis and caspase activation in Jurkat cells, a malignant T-cell line. Methods: Jurkat cells were incubated with ALA in the presence of [14C]-thymidine followed by red light exposure. DNA fragmentation was measured 24 hours later with a DNA elution assay. The influence on DNA fragmentation of ALA concentration, time between ALA addition and light exposure, as well as light fluence were studied. The occurrence of oligonucleosome-sized DNA fragmentation was also studied with DNA electrophoresis. Caspase-3-like activity was monitored by measuring Ac-DEVD-AMC hydrolysis. Results: DNA fragmentation as high as 88% was observed 24 hours after ALA-PDT. The percentage of DNA fragmentation increased with increasing doses of ALA, red light fluence, as well as longer incubation time with ALA. DNA fragmentation was observed as early as 3 hours after ALA-PDT. The presence of apoptosis after ALA-PDT was confirmed by DNA electrophoresis. An increase in caspase-3-like activities was detected following ALA-PDT. Conclusion: ALA-PDT induces apoptosis and caspase-3-like activation in Jurkat cells.

scholarly journals Effects of Light Dosimetry in Photobleaching of The Photosensitizer (PS) and Cyanine Dye (CD) Moieties in Ps-Cd Conjudates and Its Correlation with Photodynamic Therapy (PDT) Efficacy

2018 ◽  
Author(s):  
Nadine James ◽  
Ravindra R. Cheruku ◽  
Joseph R. Missert ◽  
Ulas Sunar ◽  
Ravindra K. Pandey
Keyword(s):  
Photodynamic Therapy ◽  
Fluorescence Imaging ◽  
Near Infrared ◽  
Tumor Response ◽  
Cyanine Dye ◽  
Fluence Rate ◽  
Low Light ◽  
Light Dosimetry ◽  
Light Fluence

Photodynamic therapy (PDT) of cancer is dependent on three primary components: photosensitizer (PS), light, and oxygen. Because these components are interdependent and vary during the dynamic process of PDT, assessing PDT efficacy may not be trivial. Therefore, it has become necessary to develop pre-treatment planning, on-line monitoring and dosimetry strategies during PDT, which become more critical for two or more chromophore systems, e.g. PS-CD conjugates developed in our laboratory for fluorescence-imaging and PDT of cancer. In this study, we observed a significant impact of variable light dosimetry; (i) high light fluence and fluence rate (light dose: 135 J/cm2, fluence rate: 75 mW/cm2) and (ii) low light fluence and fluence rate (128 J/cm2 and 14 mW/cm2 and 128 J/cm2 and 7 mW/cm2) in photobleaching of the individual chromophores and their long-term tumor response. The fluorescence at the near-infrared (NIR) region of the PS-NIR fluorophore conjugate was assessed intermittently via fluorescence imaging. The loss of fluorescence, photobleaching, caused by singlet oxygen from the PS was mapped continuously during PDT. The tumor responses (BALB/c mice bearing Colon26 tumors) were assessed after PDT by measuring tumor sizes daily. Our results showed distinctive photobleaching kinetics rates between the PS and CD. Interestingly, compared to higher light fluence, the tumors exposed at low light fluence showed reduced photobleaching and enhanced long-term PDT efficacy. The presence of NIR fluorophore in PS-CD conjugates provides an opportunity of fluorescence imaging and monitoring the photobleaching rate of the CD moiety for large and deeply seated tumors and assessing PDT tumor response in real-time.

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