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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 53 (1991), S. 260-264 
    ISSN: 1432-0649
    Keywords: 07.65-b ; 07.20.ka ; 33.20.kf
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract An intensified multi-colour digital imaging system allowing simultaneous monitoring of light from an object in four wavelength bands was used for flame emission studies. The spatial distribution of the molecular emission from different flame radicals, such as OH, C2, CH, and CN was recorded, also in the presence of a heavy background due to Planck-radiating soot particles. Exposure times down to 8 μs could be reached allowing studies of turbulent flames. The imaging spectroscopic recordings were supported by simultaneous point monitoring of the full emission spectrum. A technique for imaging flow measurements using a spectroscopic gas correlation technique is proposed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1084
    Keywords: Time resolve ; Transillumination measurements ; Breast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The objective of this study was to evaluate a pulsed laser transillumination technique based on time-resolved detection on breast-tissue-like phantoms. Experiments have been performed on tissue-like plastic phantoms with different scattering characteristics. The effects of time-gate width, size, localisation and refractive index of hidden objects have been scrutinised. Our study showed that the shorter the time-gate the higher the contrast. The contrast is very dependent on the size of the hole, whereas the full width half maximum is not. Furthermore, the investigation showed that the changes of early detected light in an experimental setting is due to scattering, and not to a higher speed of the transmitted light
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Photochemistry and Photobiology B: Biology 4 (1990), S. 363-369 
    ISSN: 1011-1344
    Keywords: Atherosclerosis ; fluorescence ; picosecond laser ; time-resolved spectroscopy ; tissue diagnosis.
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Photochemistry and Photobiology B: Biology 16 (1992), S. 155-167 
    ISSN: 1011-1344
    Keywords: Picosecond spectroscopy ; gated viewing ; optical transillumination ; tissue optical properties. ; turbid media
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy Section 46 (1990), S. 1203-1210 
    ISSN: 0584-8539
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Eighty basal cell carcinomas (BCCs) in 21 patients, 10 lesions of Bowen's disease in three patients, and four lesions of cutaneous T-cell lymphoma in two patients, were treated with photodynamic laser therapy (PDT), using topical application of the haem precursor δ-amino levulinic acid (ALA). The diagnoses were confirmed histologically prior to treatment. Fifty-five of the BCCs were superficial lesions, and 25 were nodular. Of the 80 BCCs, 39 (49%) were located on the trunk, 36 (45%) on the head and neck region, four (15%) on the leg and one on the arm. The two principal locations of the 10 Bowen's disease lesions were the leg (50%) and the trunk (40%). The T-cell lymphoma lesions were located on the shoulder and on the arm. A water-in-oil based cream containing 20% ALA was applied to the lesions, with a margin of about 10–20 mm beyond the visible tumour border, 4–6 h before the laser procedure. During this period of time the highly fluorescent and photodynamically active substance protoporphyrin IX (Pp IX) is synthesized via the haem cycle. Laser-induced fluorescence (LJF) was used for real-time monitoring of the Pp IX distribution in the tumour and in the normal surrounding skin, before and after treatment in all patients. Before laser treatment the Pp IX distribution demonstrated by LJF showed a demarcation between tumour and normal skin of about 15:1 for BCC and Bowen's disease, and 5:1 for T-cell lymphomas. Laser light from a pulsed frequency- doubled Nd: YAG laser pumping a dye laser with light emission at 630 nm was used for the therapy. The power density in the irradiation was kept below 110 mW/cm2, in order to avoid hyperthermal effects. A total energy of 60 J/cm2 was delivered for 10–20 min, depending on the tumour size. A complete response rate of 100% in superficial BCCs and 64% in nodular BCCs occurred after a single laser treatment, and a response rate of 100% was achieved after one additional treatment in the nodular BCCs. In the Bowen's disease lesions a complete response of 90% was obtained with a single treatment. Two of the four T-cell lymphomas resolved completely. The follow-up time was between 6 and 14 months.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Summary Background Photodynamic therapy (PDT) is a local treatment modality with increasing indications for various malignant and non malignant diseases. The treatment parameters have not yet been optimized as there is a need for a better understanding of the process. The skin is an important target and serves as a good model for monitoring and evaluating the interaction of light with biological tissue. Objectives The tissue perfusion and the temperature of basal cell carcinomas were measured in connection with PDT in order to investigate the biological mechanisms involved. Methods An infrared camera was used during the treatment to measure skin temperature and a laser Doppler perfusion imaging device was used to image the superficial perfusion before and after treatment. Six hours after topical application of 5-aminolaevulinic acid (ALA) or methyl esterified ALA (ALA–ME), 38 basal cell carcinomas were treated using light from a diode laser at 633 nm. Results In the lesions, the perfusion immediately after PDT was similar to that before PDT. One hour after the treatment the perfusion in the lesion was increased 50% compared with before PDT. However, in the skin surrounding the lesions the perfusion was doubled immediately after PDT and was still increasing 1 h after treatment. A temperature increase in the lesions of about 1–3 °C was observed for light fluence rates of 100–150 mW cm−2. In all patients treated, a diffuse temperature increase was visible outside the lesions. In some of the patients, the outlines of the blood vessels surrounding the treated lesions became visible in the thermal images. Measurements of temperature on healthy volunteers not administered photosensitizer, but illuminated with light of the same fluence rate, showed a similar increase in temperature in the illuminated spots. However, no temperature increase was observed outside the illuminated area. No statistically significant differences were found between the measurements on patients treated with ALA and ALA–ME. Conclusions The increased perfusion in the area surrounding the lesions after PDT, as seen by perfusion and temperature measurements, is the result of an inflammatory reaction to the PDT process. However, directly after PDT the perfusion in the lesions was the same as before irradiation. The combination of these observations suggests the presence of local blood stasis during and immediately after the treatment. The temperature measurements showed that the increased temperature was well below the temperature limit of hyperthermal damage. Furthermore, the measurements indicate that the increase in temperature was primarily a consequence of the heat absorbed in the tissue.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background A previously reported randomized clinical trial showed treatment of Bowen's disease using photodynamic therapy (PDT) with topically applied δ-aminolaevulinic acid (ALA) to be at least as effective as cryosurgery and to be associated with fewer adverse effects. Objectives To compare ALA-PDT and cryotherapy in the treatment of histopathologically verified basal cell carcinomas (BCCs) in a non-blinded, prospective phase III clinical trial. Methods One lesion from each of 88 patients was included. The BCCs were divided into superficial and nodular lesions. The follow-up period was restricted to 1 year with close follow-up for the first 3 months. Efficacy was assessed as the recurrence rate 12 months after the first treatment session, verified by histopathology. Tolerability was evaluated as the time of healing, pain and discomfort during and after the treatment, and final cosmetic outcome. Results Histopathologically verified recurrence rates in the two groups were statistically comparable and were 25% (11 of 44) for ALA-PDT and 15% (six of 39) for cryosurgery. However, clinical recurrence rates were only 5% (two of 44) for PDT and 13% (five of 39) for cryosurgery. Additional treatments, usually one, had to be performed in 30% of the lesions in the PDT group. The healing time was considerably shorter and the cosmetic outcome significantly better with PDT. Pain and discomfort during the treatment session and in the following week were low, and were equivalent with the two treatment modalities. Conclusions In terms of efficacy, ALA-PDT is comparable with cryosurgery as a treatment modality for BCCs. Retreatments are more often required with PDT than with cryosurgery. This can easily be performed due to the shorter healing time, less scarring and better cosmetic outcome that follows ALA-PDT.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Laser Doppler perfusion imaging offers a new modality for in vivo monitoring of the superficial blood perfusion in biological tissue. In this study, the superficial blood perfusion of malignant nonmelanoma skin tumours and the surrounding normal skin was measured in conjunction with photodynamic therapy (PDT) using topical ò–aminolaevulinic acid (ALA)–induced protoporphyrin IX as a photosensitizer. The results clearly show that, in contradiction to PDT with the intravenously administered photosensitizer photofrin. no direct vascular damage can be seen. With the topical sensitization the blood perfusion is increased immediately after the treatment irradiation. The increased blood flow is seen up to a week after treatment, in a similiar way as for an inflammatory reaction. Despite this, all basal cell carcinoma and squamous cell carcinoma in situ lesions in this study healed without any sign of residual tumour after the treatment, suggesting an efficient direct tumour cell destruction induced by PDT.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1435-604X
    Keywords: Cancer detection ; Fluorescence spectroscopy ; Haematoporphyrin derivative ; Laser excitation ; Phthalocyanine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract Several photosensitizers were screened for their tumour-marking ability using laserinduced fluorescence in Wistar/Furth rats bearing subcutaneous adenocarcinomas inoculated in muscle. Of the studied photosensitizers, dihaematoporphyrin ether appeared to exhibit the best tumour-demarcation properties. Polyhaematoporphyrin ester and tetrasulfonated phthalocyanine were almost as good although the fluorescence yield was much lower. Monomeric haematoporphyrin also showed some tumour-marking qualities. By forming fluorescence intensity ratios, information from both the blue and the red spectral regions were used to provide the highest tumour-to-muscle contrast. Two excitation wavelengths were used, of which 337 nm rather than 405 nm excitation light seemed to yield a better tumour demarcation, due to a greater difference in the superimposing autofluorescence between tumour and surrounding tissue. The study included measurements on many inner organs in an attempt to gain a better understanding of the interaction between the drugs and various kinds of tissue.
    Type of Medium: Electronic Resource
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