&lt;title&gt;Tissue As A Medium For Laser Light Transport-Implications For Photoradiation Therapy&lt;/title&gt;

Preuss, Luther E.; Bolin, F. P.; Cain, B.

doi:10.1117/12.976076

Cited by 19 publications

(5 citation statements)

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“…Measurements on bulk tissue are considered to be the best method to determine the effective attenuation coefficient. If we limited our comparison at 630 and 632.8 nm to interstitial fibre measurements, µ eff for muscle, liver, and lung is 2.7-12.5, 11.0, and 12.5-13.0 respectively (Doiron et al 1982, 1983, Preuss et al 1982, Wilson et al 1985, Bolin et al 1987, Flock et al 1987, Marijnissen and Star 1987. Our calculated µ eff is comparable for muscle and lung and is a factor of two higher for liver.…”

Section: Discussionmentioning

confidence: 70%

“…Variations in optical properties at 630-635 nm as found in the literature are also large. For instance, values for muscle are 0.2 g 0.97, 4.3 µ t 345, 0.12 µ a 1.7, 4.1 µ s 45 (µ s was not measured separately for µ t = 345 by Karagiannes et al (1989)), 1.2 µ s 7.0, and 1.1 µ eff 12.5 (Doiron et al 1982, 1983, Preuss et al 1982, Wilksch et al 1984, Wilson et al 1985, 1986, Marijnissen et al 1985, Bolin et al 1987, Flock et al 1987, Marijnissen and Star 1987, McKenzie and Byrne 1988, Karagiannes et al 1989 We emphasize that a comparison of optical properties measured by different investigators is in general difficult, because of differences in the materials used. For instance, a comparison of the in vitro absorption coefficient of a black, tar-containing deflated lung of a male adult, with the in vivo absorption coefficient of the whitish lung of a piglet is, obviously, of little use.…”

Section: Discussionmentioning

confidence: 99%

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In vitrodouble-integrating-sphere optical properties of tissues between 630 and 1064 nm

et al. 1997

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In vitro double-integrating-sphere optical properties of tissues between 630 and 1064 nm Beek, J.F.; Blokland, P.; Posthumus, P.; Aalders, M.C.G.; Pickering, J.W.; Sterenborg, H.J.C.M.; van Gemert, M.J.C. Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Abstract. The optical properties (absorption and scattering coefficients and the scattering anisotropy factor) were measured in vitro for cartilage, liver, lung, muscle, myocardium, skin, and tumour (colon adenocarcinoma CC 531) at 630, 632.8, 790, 850 and 1064 nm. Rabbits, rats, piglets, goats, and dogs were used to obtain the tissues. A double-integrating-sphere setup with an intervening sample was used to determine the reflectance, and the diffuse and collimated transmittances of the sample. The inverse adding-doubling algorithm was used to determine the optical properties from the measurements. The overall results were comparable to those available in the literature, although only limited data are available at 790-850 nm. The results were reproducible for a specific sample at a specific wavelength. However, when comparing the results of different samples of the same tissue or different lasers with approximately the same wavelength (e.g. argon dye laser at 630 nm and HeNe laser at 632.8 nm) variations are large. We believe these variations in optical properties should be explained by biological variations of the tissues. In conclusion, we report on an extensive set of in vitro absorption and scattering properties of tissues measured with the same equipment and software, and by the same group. Although the accuracy of the method requires further improvement, it is highly likely that the other existing data in the literature have a similar level of accuracy.

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Section: Discussionmentioning

confidence: 70%

Section: Discussionmentioning

confidence: 99%

In vitrodouble-integrating-sphere optical properties of tissues between 630 and 1064 nm

et al. 1997

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“…Our spectral data indicate that 442 nm excitation and 514 nm excitation are more efficient at inducing fluorescence than 405 nm light. Longer excitation wavelengths are desirable because they are more easily transmissible through tissue (i.e., penetrate the tissue more deeply per unit of time and energy) [10,17,181. Another reason to use 442 nm as an excitation source is the greater luminance of fluorescence from DHE.…”

Section: Discussionmentioning

confidence: 99%

Methods for the endoscopic photographic and visual detection of helium cadmium laser‐Induced fluorescence of photofrin II

Rogers

Lanzafame

Blackman³

et al. 1990

Lasers Surg Med

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Endoscopic detection of small tumors is key to the early diagnosis and treatment of malignancy. This paper describes a simple, endoscopic detection system which enables tumor localization and a permanent record based on the laser-induced fluorescence of dihematoporphyrin ether (LIFD). Spectral analysis of dihematoporphyrin ether (DHE, Photofrin II) was performed with a Perkin Elmer LS-5 scanning fluorimeter. DHE at concentrations of 50 micrograms/ml and 5 micrograms/ml in 95% ethanol were tested, demonstrating fluorescence quenching at 50 micrograms/ml DHE at 406 nm excitation. This phenomenon was not observed at 442 nm excitation. Based on this data and the availability of the helium cadmium laser, a series of endoscopic detection systems was developed and tested utilizing a LiConix 4240NB helium cadmium laser (TEMoo, 442 nm, 40 mW). A fiber with a microdiverging (MDL) lens was used. Irradiance achieved at the tip of the fiber was 31.58 mW/cm2 for MDL. A Corning 34832 (550 nm) sharp cutoff barrier filter was coupled to an Olympus OES BF2T10 bronchoscope. Successful detection of LIFD was obtained. Direct observation of LIFD is possible when wearing Laserguard argon safety goggles (OD 15 at 488 nm, OD 11 at 514 nm). Photographic recording of LIFD was performed with the following cameras and parameters: Olympus OM-2S camera (OM2) with EES135 film (ISO 1600) with a 4-second exposure (method 1) and the Olympus OES SCP-10 instant camera with Polaroid 779 (ISO 640) film and a 120-second exposure (method 2). The photographic methods demonstrate the red fluorescence of DHE on filter paper disks at concentrations of 0.5 micrograms/ml (500 ng/ml). (ABSTRACT TRUNCATED AT 250 WORDS)

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“…These equations correspond respectively to exponential, diffusion dominant, and absorption dominant dispersion modes (Preuss et al, 1982;Doiron et al, 1983;and Svaasand and Ellingsen, 1983). In all cases, the fiber tip was assumed to have radius a = 0.1 mm.…”

Section: Methodsmentioning

confidence: 99%

OPTIMIZATION OF PHOTODYNAMIC THERAPY LIGHT DOSE DISTRIBUTION and TREATMENT VOLUME BY MULTI‐FIBER INSERTIONS*

Bolin

Preuss

Taylor

1987

Photochem & Photobiology

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The development of a methodology which optimizes the light dosage in tissue and improves the tailoring of the light with consequent sparing of normal adjacent tissue, will enhance the possibility for routine clinical photodynamic therapy. Specific, important goals for the clinical use of PDT are (a) efficient distribution of light flux to all parts of the tumor at sufficient level to effect eradication. (b) avoidance of the destruction of adjacent normal tissue, and (c) ability to tailor the treatment field, taking into account the varied shapes of tumors. Dividing the available power among several fibers is a promising method of achieving these goals. This is accomplished by (1) extending the volume, and by (2) increasing the flux spatial uniformity. This latter defocussing of the flux field is especially important because it may help to avoid concentrating a high intensity field from an implanted fiber near an essential structure of the normal tissue. The question arises how best to orient these multiple fibers for maximum coverage and uniformity. Hence, theoretical and experimental investigations were made to determine optimal fiber placements. A series of intensity distributions were generated using two and three fibers positioned at various separations within a postulated tumor volume. A criterion for uniformity was defined. Iterative computation produced optimal fiber separation for the given constraints. In the two fiber case, for small values of attenuation coefficient (μ. ≦ 0.2 mm−1), optimal fiber separation ranged from 0.6 to 0.7 times the diameter of the defined volume. For large values of attenuation coefficient (μ. ≧ 0.8), fiber separation was about 0.5 to 0.55 times the region diameter. The effects of fiber separation on volume of treatment were also determined. Maximal treatment volume was found to be dependent on the attenuation coefficient. With μ, = 0.50, a 40% increase in treatment volume over single fiber insertion of equivalent energy input was shown to be obtainable with a dual fiber configuration of 24 mm separation. Experiments using two fibers in vitro in mammalian tissue were performed to substantiate these results. The multiple fiber system is a promising method for delivering optimum light dosage to targeted PDT tissue.

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<title>Tissue As A Medium For Laser Light Transport-Implications For Photoradiation Therapy</title>

Cited by 19 publications

References 0 publications

In vitrodouble-integrating-sphere optical properties of tissues between 630 and 1064 nm

In vitrodouble-integrating-sphere optical properties of tissues between 630 and 1064 nm

Methods for the endoscopic photographic and visual detection of helium cadmium laser‐Induced fluorescence of photofrin II

OPTIMIZATION OF PHOTODYNAMIC THERAPY LIGHT DOSE DISTRIBUTION and TREATMENT VOLUME BY MULTI‐FIBER INSERTIONS*

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