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Amelink A van der Ploeg van den Heuvel A de Wolf WJ Robinson DJ Sterenborg HJ 《Journal of photochemistry and photobiology. B, Biology》2005,79(3):243-251
Monitoring of relevant parameters during photodynamic therapy (PDT) and correlating these with treatment response is necessary to guarantee optimal and reproducible treatment outcome. In this paper we study the correlation between changes in the local tissue optical properties (absorption and scattering coefficients) during ALA-PDT and changes in PpIX fluorescence. The optical properties are measured extremely superficially by employing a single fiber for the delivery and collection of white light to and from the tissue. The measured reflectance spectrum is modeled in terms of four relevant parameters: blood saturation, relative blood volume fraction, scattering intensity and wavelength dependence of the scattering. All these parameters, except the relative blood volume fraction, are shown to correlate with the rate of photobleaching of PpIX, which in turn has previously been shown to correlate with the response of tissues to PDT. These results yield valuable insight in the behavior of these parameters during PDT and their suitability to predict PDT-response for other photosensitizers for which monitoring through photobleaching is not possible. 相似文献
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Values for the specific rates of solvolysis of the benzhydryldimethylsulfonium ion in 34 solvents have been analyzed using various forms of the extended Grunwald-Winstein equation. The specific rates are insensitive toward changes in solvent nucleophilicity (N(T)) values, and they correlate best against a combination of Y(+) values (based on the solvolyses of the 1-adamantyldimethylsulfonium ion) and aromatic ring parameter (I) values. Common-molecule return is observed, being especially powerful in solvents rich in fluoro alcohol; the logarithm of the associated mass law constant correlates inversely with the solvent N(T) values. The product selectivities in ethanol-water mixtures are also consistent with an S(N)1 mechanism for the solvolyses. 相似文献
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H. J. C. M. Sterenborg F. R. de Gruul G. Kelfkens J. C. van der Leun 《Photochemistry and photobiology》1991,54(5):775-780
The relative risk of occupational exposure to radiation from UV lasers was estimated using a mathematical model based on both epidemiological data and animal experiments. Calculations were performed for the 193 nm ArF excimer laser cornea shaping, the 308 nm XeCl excimer laser for coronary angioplasty, and other UV lasers in a laboratory environment. The model included the effects of direct exposure and exposure to scattered radiation. The results show that for the two medical applications the increase in the relative risk is comparable to that of one additional day of sunbathing per year. For subjects exposed to UV lasers in a laboratory setting, the relative risk may increase to a value comparable to that of people with an outdoor profession. 相似文献