Dr. Bin Chen Profile

Dr. Bin Chen

Research Scientist at Dartmouth College

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Publications (6)

Proceedings Article | 27 February 2007 Paper

Tumor vascular volume determines photosensitizer uptake in MATLyLu prostate tumor model

Xiaodong Zhou, Bin Chen, P. Jack Hoopes, Tayyaba Hasan, Brian Pogue

Proceedings Volume 6427, 64270S (2007) https://doi.org/10.1117/12.699033

KEYWORDS: Tumors, Luminescence, Diffusion, Molecules, Cancer, Data modeling, Photodynamic therapy, Tissues, Plasma, Prostate

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Proceedings Article | 6 March 2006 Paper

Analysis of cell line variation in biochemical production of protoporphyrin IX

Summer Gibbs, Bin Chen, Julia O'Hara, P. Jack Hoopes, Tayyaba Hasan, Brian Pogue

Proceedings Volume 6139, 61390A (2006) https://doi.org/10.1117/12.644787

KEYWORDS: Luminescence, Iron, Lithium, Flow cytometry, Cancer, Photodynamic therapy, Statistical analysis, Tissues, Prostate, Scatter measurement

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Protoporphyrin IX (PpIX) is produced via the heme synthesis pathway by the cell following administration of aminolevulinic acid (ALA). ALA synthase, the enzyme that produces ALA in the cell from glycine and succinyl-coenzyme A, is inhibited in a feedback mechanism by heme and thus is the rate limiting enzyme in the heme synthesis pathway. Since ALA is administered systemically, the rate limiting step that naturally exists in the cells is bypassed, however it is currently unclear why cells have different rate limiting steps in the ALA-PpIX synthesis pathway, and more specifically which types of cancer cells are most productive. It has been determined that when the same amount of ALA is administered to a wide panel of cancer cells in vitro that vastly differing amounts of PpIX are produced. The steps for the ALA-PpIX pathway occur in and around the mitochondria of the cell, but interestingly no correlation is seen between PpIX production and mitochondrial content of the cell, following ALA administration. However, total cell area shows positive correlation with PpIX production. Administration of the iron chelator, 1,2-dimethyl-3-hydroxy-4-pyridone (L1) in combination with ALA allows the final step in the heme synthesis pathway, conversion of PpIX to heme, to be delayed and thus increases the detectable amount of PpIX in each cell line. The cell lines that have the lowest PpIX production following administration of ALA alone show the largest increase in production following the combined administration of ALA and L1. PpIX fluorescence is thought to be a measure of cellular activity and the goal of the current study was to determine which cell lines would be the most promising targets for fluorescence detection or monitoring response to therapy. The results indicate that the cells with larger size and larger numbers of mitochondria may be good potential targets for this therapy. While this conclusion may appear obvious, it is not universally true, and cellular specific variations exist which are still not fully understood.

Proceedings Article | 6 March 2006 Paper

Photosensitizer dosimetry controlled PDT treatment planning reduces inter-individual variability in response to PDT

Xiaodong Zhou, Brian Pogue, Bin Chen, Eugene Demidenko, Rohan Joshi, Jack Hoopes, Tayyaba Hasan

Proceedings Volume 6139, 61390P (2006) https://doi.org/10.1117/12.647439

KEYWORDS: Tumors, Photodynamic therapy, Picosecond phenomena, Luminescence, Tissue optics, Animal model studies, Tissues, Oxygen, Prostate, In vivo imaging

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Effective Photodynamic therapy (PDT) treatment depends on the amount of active photosensitizer and the delivered light in the targeting tissue. For the same PDT treatment protocol, variation in photosensitizer uptake between animals induces variation in the treatment response between animals. This variation can be compensated via control of delivered light dose through photodynamic dose escalation based on online dosimetry of photosensitizer in the animal. The subcutaneous MAT-LyLu Dunning prostate tumor model was used in this study. Photosensitizer BPD-MA uptake was quantified by multiple fluorescence micro-probe measurements at 3 hours after verteporfin administration. PDT irradiation was carried out after photosensitizer uptake measurement with a total light dose of 75 J/cm2 and a light dose rate of 50 mW/cm2. Therapeutic response of PDT treatments was evaluated by the tumor regrowth assay. Verteporfin uptake varied considerably among tumors (inter-tumor variation 56% standard deviation) and within a tumor (largest intra-tumor variation 64%). An inverse correlation was found between mean photosensitizer intensity and PDT treatment effectiveness (R2 = 37.3%, p < 0.005). In order to compensate individual PDT treatments, photodynamic doses were calculated on an individual animal basis, by matching the light delivered to provide an equal photosensitizer dose multiplied by light dose. This was completed for the lower-quartile, mean and upper-quartile of the photosensitizer distribution. The coefficient of variance in the surviving fraction decreased from 24.9% in non-compensated PDT (NC-PDT) treatments to 16.0%, 14.0% and 15.9% in groups compensated to the lower-quartile (CL-PDT), the median (CM-PDT) and the upper-quartile (CU-PDT), respectively. In terms of treatment efficacy, the CL-PDT group was significantly less effective compared with NC-PDT, CM-PDT and CU-PDT treatments (p < 0.005). No significant difference in effectiveness was observed between NC-PDT, CM-PDT and CU-PDT. The results indicate that by measuring the mean photosensitizer concentration prior to light treatment, and then adjusting the light dose appropriately, a more uniform treatment can be applied to different animals thereby reducing the inter-individual variation in the treatment outcome.

SPIE Journal Paper | 1 July 2005 Open Access

Analysis of sampling volume and tissue heterogeneity on the in vivo detection of fluorescence

Brian Pogue, Bin Chen, Xiaodong Zhou, P. Jack Hoopes

JBO, Vol. 10, Issue 04, 041206, (July 2005) https://doi.org/10.1117/12.10.1117/1.2002978

KEYWORDS: Luminescence, Tumors, Tissues, In vivo imaging, Tissue optics, Microscopy, Statistical analysis, Signal detection, Biological research, Fluorescence spectroscopy

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Proceedings Article | 13 June 2003 Paper

Effect of photodynamic therapy with verteporfin on tumor blood flow

Bin Chen, Brian Pogue, Isak Goodwin, Julia O'Hara, Carmen Wilmot, John Hutchins, P. Hoopes, Tayyaba Hasan

Proceedings Volume 4952, (2003) https://doi.org/10.1117/12.474082

KEYWORDS: Tumors, Photodynamic therapy, Blood circulation, Tissues, Doppler effect, Blood vessels, Oxygen, Luminescence, Laser systems engineering, Cancer

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Proceedings Article | 13 June 2003 Paper

Increasing oxygenation and radiation sensitivity following photodynamic therapy with verteporfin in the RIF-1 tumor

Brian Pogue, Julia O'Hara, Eugene Demidenko, Carmen Wilmot, Bin Chen, Harold Swartz, Tayyaba Hasan

Proceedings Volume 4952, (2003) https://doi.org/10.1117/12.473594

KEYWORDS: Tumors, Photodynamic therapy, Blood circulation, Radiotherapy, Oxygen, Tissues, Radiation effects, In vivo imaging, In vitro testing, Doppler effect

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