| 1. |
- 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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| 2. |
- Sturesson, C, et al.
(författare)
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A mathematical model for predicting the temperature distribution in laser-induced hyperthermia. Experimental evaluation and applications
- 1995
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 1361-6560 .- 0031-9155. ; 40:12, s. 2037-2052
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Tidskriftsartikel (refereegranskat)abstract
- A time-dependent mathematical model for the heat transfer in laser-induced hyperthermia has been developed. The model calculates the temperature distribution in surface-irradiated tissues. Good agreement was found between the predictions of the model and in vitro experimental results obtained for bovine liver irradiated with an expanded beam from a Nd:YAG laser. Surface evaporation of water was included in the model and experimentally verified. The discrepancy between the measured and the calculated rise in temperature at three different depths on the axis of symmetry of the irradiating beam was found to be less than 5% after 15 min of irradiation. When irradiating in air and not accounting for the surface evaporation in the model, the accuracy of the model predictions was only 75-80%. The model was then used to investigate the influence of surface evaporation of water on the total temperature distribution theoretically in a clinically relevant case. From the numerical simulations, it was shown that, simply by providing a moistened liver surface, the maximum steady-state temperature could be forced into the tissue to a depth of 4 mm. It was also shown that, by employing the numerical model during the initial phase of hyperthermia treatment, overshooting of the temperature during the transient thermal build-up time could be prevented.
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| 3. |
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| 4. |
- Sturesson, C, et al.
(författare)
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Theoretical analysis of transurethral laser-induced thermo-therapy for treatment of benign prostatic hyperplasia. Evaluation of a water-cooled applicator
- 1996
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 1361-6560 .- 0031-9155. ; 41:3, s. 445-463
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Tidskriftsartikel (refereegranskat)abstract
- A mathematical model for predicting the temperature rise in transurethral laser-induced thermo-therapy for benign prostatic hyperplasia was developed. In the model an optical line source emitting light from an Nd:YAG laser isotropically was placed in the urethra. Water cooling of the urethral epithelium was modelled using a two-tube system. The relationship between the difference in outlet and inlet water temperatures and the highest tissue temperature level reached was theoretically investigated. It was found that the water temperature difference was linearly dependent on the steady-state maximum tissue temperature. The theoretical calculations suggest that the water-cooled applicator can be used to measure the maximum tissue temperature. With temperature control, the prostatic tissue temperature can be prevented from exceeding the boiling point of water, excluding tissue carbonization. The model was also used to evaluate the influence of a number of different parameters on the damaged tissue volume. Increasing the urethral lumen radius by a factor of two by means of inserting different sized tubes was found to augment the tissue volume raised to therapeutic temperatures by up to 50%. The calculations showed that cooling of the urethral epithelium can result in an increase in the damaged volume by 80% as compared to not applying any cooling. The temperature of the cooling water was found to influence the tissue temperature only to a small extent.
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