| 1. |
- Sturesson, C, et al.
(författare)
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Hepatic inflow occlusion increases the efficacy of interstitial laser-induced thermotherapy in rat
- 1997
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Ingår i: Journal of Surgical Research. - : Elsevier BV. - 1095-8673 .- 0022-4804. ; 71:1, s. 67-72
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Tidskriftsartikel (refereegranskat)abstract
- Interstitial laser-induced thermotherapy (ILT) destroys tumors thermally, ILT was performed for treatment of liver tumors in rats to investigate the effect of hepatic inflow occlusion on temperature distribution and lesion size. Tumors were irradiated for 20 min with near-infrared light from a neodymium:yttrium-aluminum-garnet (Nd:YAG) laser, The laser light at a power of 1.5 W was delivered through a plane-cut optical fiber, the tip of which was placed in the tumor. Rats in group I received ILT without interruption of hepatic blood flow. Those in group II received ILT during hepatic inflow occlusion. Liver temperatures were measured during treatment. After 3 days the animals were sacrificed and the size of the lesions was measured. Occlusion of the hepatic inflow during ILT increased the maximum lesion diameter, as measured at the liver surface, by 47%. Linear interpolation between the temperatures measured at 6 and 12 mm distance from the fiber tip revealed that the temperature at the necrotic border just before the end of treatment was approximately 45 degrees C in both the occluded and nonoccluded groups, indicating that the hepatic inflow occlusion caused no increase in tissue thermal sensitivity, This study shows that occlusion of the hepatic in-flow during interstitial laser-induced thermotherapy causes a significant increase in lesion size, which could have implications for the treatment of hepatic tumors. (C) 1997 Academic Press.
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| 2. |
- Andersson-Engels, Stefan, et al.
(författare)
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In vivo fluorescence imaging for tissue diagnostics
- 1997
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 1361-6560 .- 0031-9155. ; 42:5, s. 815-824
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Tidskriftsartikel (refereegranskat)abstract
- Non-invasive fluorescence imaging has the potential to provide in vivo diagnostic information for many clinical specialities. Techniques have been developed over the years for simple ocular observations following UV excitation to sophisticated spectroscopic imaging using advanced equipment. Much of the impetus for research on fluorescence imaging for tissue diagnostics has come from parallel developments in photodynamic therapy of malignant lesions with fluorescent photosensitizers. However, the fluorescence of endogenous molecules (tissue autofluorescence) also plays an important role in most applications. In this paper, the possibilities of imaging tissues using fluorescence spectroscopy as a mean of tissue characterization are discussed. The various imaging techniques for extracting diagnostic information suggested in the literature are reviewed. The development of exogenous fluorophores for this purpose is also presented. Finally, the present status of clinical evaluation and future directions are discussed.
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| 3. |
- Heyerdahl, H, et al.
(författare)
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Pharmacokinetic studies on 5-aminolevulinic acid-induced protoporphyrin IX accumulation in tumours and normal tissues
- 1997
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Ingår i: Cancer Letters. - 1872-7980. ; 112:2, s. 225-231
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Tidskriftsartikel (refereegranskat)abstract
- Laser-induced fluorescence (LIF) for in vivo point monitoring and fluorescence microscopy incorporating a CCD camera were used to study the fluorescence distribution of 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) in tumours. Fluorescence in a chemically induced adenocarcinoma in the liver of rats and in an aggressive basal cell carcinoma in a patient were studied after intravenous injection of ALA at a dose of 30 mg/kg body weight. The LIF technique demonstrated slightly more ALA-induced PpIX fluorescence in the tumour than in the surrounding normal liver and abdominal muscle of rats. The visible parts of the human basal cell carcinoma exhibited strong ALA-induced fluorescence, while this fluorescence was much weaker in the necrotic areas of the tumour and in the surrounding normal skin. (C) 1997 Elsevier Science ireland Ltd.
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| 4. |
- Jarlman, O, et al.
(författare)
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Time-resolved white light transillumination for optical imaging
- 1997
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Ingår i: Acta Radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 38:1, s. 185-189
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To describe a new breast-imaging method with the potential of multi-spectral optical transillumination based on a time-resolved technique. Material and Methods: A breast phantom was irradiated with ultra-short laser pulses of white light generated by self-phase modulation of an incident high-power laser pulse in water. Time-resolved detection of the transmitted light was performed. Contrast resolution was studied using different absorbers located inside the breast phantom. Results and Conclusion: The results showed that simultaneous, multi-spectral transillumination is possible. The technique can also be used for measurements of optical properties in tissue.
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| 5. |
- Liu, D. L, et al.
(författare)
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Tumour vessel damage resulting from laser-induced hyperthermia alone and in combination with photodynamic therapy
- 1997
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Ingår i: Cancer Letters. - 1872-7980. ; 111:1-2, s. 157-165
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Tidskriftsartikel (refereegranskat)abstract
- This study examined tumour vessel injury resulting from laser-induced hyperthermia alone and in combination with photodynamic therapy (PDT) in the treatment of rat liver tumours by means of scanning electron microscopy. A total of 18 Wistar rats were divided into three groups, Group I (six animals) underwent hyperthermia for 15 min (15-min hyperthermia). Group II (six animals) underwent hyperthermia for 30 min (30-min hyperthermia). Group III (six animals) received the combined treatment of PDT and 30-min hyperthermia. For PDT, delta-amino laevulinic acid at a dose of 60 mg/kg of body weight was intravenously administered 60 min before irradiation at 635 nm. The morphological results indicated that 15-min hyperthermia gave rise to an increase in permeability of the vessels in the treated tumour. Thirty-min hyperthermia caused extreme oedema of vascular endothelial cells and restrictive openings of tumour branch vessels. The combined therapy of PDT and hyperthermia destroyed tumour vasculature. Large breaks of the inner wall of the treated tumour vessels were deeply involved in the basement membrane of the vessel. The results indicate that there may be a close link between inhibition of tumour growth and degree of damage to tumour vessels. (C) 1997 Elsevier Science Ireland Ltd.
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| 6. |
- Wang, I, et al.
(författare)
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Superficial blood flow following photodynamic therapy of malignant non-melanoma skin tumours measured by laser Doppler perfusion imaging
- 1997
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Ingår i: British Journal of Dermatology. - : Oxford University Press (OUP). - 1365-2133 .- 0007-0963. ; 136:2, s. 184-189
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Tidskriftsartikel (refereegranskat)abstract
- 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 delta-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 brood perfusion is increased immediately after the treatment irradiation. The increased brood now is seen up to a week after treatment, in a similar 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.
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