| 1. |
- Andersson-Engels, Stefan, et al.
(författare)
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Integrated system for interstitial photodynamic therapy
- 2002
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Ingår i: Advanced Optical Devices, Technologies, and Medical Applications. - : SPIE. - 0277-786X .- 1996-756X. ; 5123, s. 293-302
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Konferensbidrag (refereegranskat)abstract
- To develop PDT beyond treatment of thin superficial tumours, to also be an efficient treatment alternative for deeply located and/or thick tumours, a system based on interstitial illumination using multiple fibres has been developed. Conditions that could benefit from such a treatment modality are for instance malignant brain tumours and tumours in the oral cavity. In interstitial PDT one needs to use multiple fibres for light delivery in order to allow treatments of tumours larger than a few millimetres in diameter. Our system consists of a laser light source, a beam-splitting system dividing the light into three or six output fibres and a custom-made dosimetry programme. The concept is then to use these fibres not only for delivering the treatment light but also to measure parameters of interest for the treatment outcome. The fluence rate of the light emitted by each fibre is measured at the positions of the other fibre tips. From these results the light dose at all positions could be recalculated. Changes in optical properties as well as bleaching and concentration of the photosensitizer during the treatment could be monitored and compensated for in the dosimetry. Tumours have been treated both in experimental studies and in patients with thick superficial Basal Cell Carcinomas. Almost all treated skin lesions responded with complete response.
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| 2. |
- Eker, Charlotta, et al.
(författare)
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Multivariate analysis of laryngeal fluorescence spectra recorded in vivo
- 2001
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Ingår i: Lasers in Surgery and Medicine. - : Wiley. - 0196-8092 .- 1096-9101. ; 28:3, s. 259-266
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Tidskriftsartikel (refereegranskat)abstract
- Background and Objective: The potential of using various multivariate analysis methods for classification of fluorescence spectra acquired in vivo from laryngeal tissues in Patients was investigated. Study Design/Materials and Methods: Autofluorescence spectra were measured on 29 normal tissue sites and 25 laryngeal lesions using 337-nm excitation. Four different multivariate analysis schemes were applied. Laryngeal fluorescence spectra from patients who had been administered F-aminolevulinic acid (ALA) were obtained using 405-nm excitation and were classified using partial least squares discriminant analysis (PLS-DA). Results: For autofluorescence spectra, logistic regression based on principal component analysis (PCA) or PLS, or PLS-DA all resulted in sensitivities and specificities around 90% for lesion vs. normal. Using ALA and 405-nm excitation gave a sensitivity of 100% and a specificity of 69%. Conclusion: Multivariate analysis of fluorescence spectra could allow classification of laryngeal lesions in vivo with high sensitivity and specificity. PLS performs at least as well as PCA, and PLS-DA performs as well as logistic regression techniques on these data.
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| 3. |
- Jensen, LK, et al.
(författare)
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Optical coherence tomography in clinical examination of non-pigmented skin malignancies
- 2003
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Ingår i: OPTICAL COHERENCE TOMOGRAPHY AND COHERENCE TECHNIQUES. - : SPIE. - 0277-786X .- 1996-756X. - 0819450103 ; 5140, s. 160-160
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Konferensbidrag (refereegranskat)abstract
- Optical coherence tomography (OCT) images of basal cell carcinomas (BCCs) have been acquired using a compact handheld probe with an integrated video camera allowing the OCT images to be correlated to a skin surface image. In general the healthy tissue of the skin has an obvious stratified structure, whereas the cancerous tissue shows a more homogenous structure. Thus it was demonstrated that it is possible to distinguish BCCs from healthy tissue by means of OCT. Furthermore different histological types of BCC were identified. Comparison of OCT images taken prior to and immediately after photodynamic therapy clearly shows the tissue response to the treatment, and indicates local oedema in the treated area.
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| 4. |
- Soto Thompson, Marcelo, et al.
(författare)
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Photodynamic therapy and diagnostic measurements of basal cell carcinomas using esterified and non-esterified delta-aminolevulinic acid
- 2001
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Ingår i: Journal of Porphyrins and Phthalocyanines. - 1099-1409. ; 5:2, s. 147-147
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Tidskriftsartikel (refereegranskat)abstract
- Various optical techniques were used to investigate relevant parameters involved in photodynamic therapy (PDT) of human basal cell carcinomas (BCCs). The aim of the study was to compare the diagnostic and therapeutic outcome when using topically applied methyl-esterified delta -aminolevulinic acid (ALA-ME) and delta -aminolevulinic acid (ALA). A total of 35 pathologically verified BCCs in 14 patients were investigated. A diode laser. emitting continuous light at 633 nm, was used to induce PDT. The diagnostic measurements were performed before, during, and after PDT. Laser-induced fluorescence (LIF) was used to monitor the build-up of the ALA/ALA-ME-induced protoporphyrin IX (PpIX), The superficial tissue perfusion was measured with laser-Doppler perfusion imaging (LDPI) and the temperature of the lesion and the surrounding tissue was imaged with an IR-camera. A clear demarcation between the lesion and the normal skin was detected with LIF before the treatment for both PpIX precursors. The fluorescence measurements suggest that PpIX builds up to a higher degree and more selectively in the tumour following ALA-ME as compared to ALA. The LDPI measurements indicate a local transient restriction in blood perfusion immediately post-PDT. The measurement with the IR-camera revealed a temperature rise of about 1-2 degreesC during the treatment.
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| 5. |
- Wang, I., et al.
(författare)
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Photodynamic therapy vs. cryosurgery of basal cell carcinomas: results of a phase III clinical trial
- 2001
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Ingår i: British Journal of Dermatology. - : Oxford University Press (OUP). - 1365-2133 .- 0007-0963. ; 144:4, s. 832-840
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Tidskriftsartikel (refereegranskat)abstract
- Background A previously reported randomized clinical trial showed treatment of Bowen's disease using photodynamic therapy (PDT) with topically applied delta -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, ISLA-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.
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| 6. |
- Andersson-Engels, Stefan, et al.
(författare)
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Integrated system for interstitial photodynamic therapy
- 2003
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 5142, s. 42-49
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Konferensbidrag (refereegranskat)abstract
- A novel photodynamic therapy system based on interstitial illumination using multiple fibres is under development. The aim with this system is to enable treatment of large tumour volumes and also to utilise real-time measurements to allow on-line dosimetry. Important dosimetric parameters to measure are light fluence rate, sensitizer fluorescence intensity and local blood oxygenation. A construction which allows all functions to be readily performed with a single system is presented. We believe that interstitial PDT utilising this technique may be attractive in many clinical situations.
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| 7. |
- deWeert, Michael J., et al.
(författare)
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Analysis of spatial variability in hyperspectral imagery of the uterine cervix in vivo
- 2003
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Ingår i: Proceedings of SPIE. - : SPIE. ; 4959, s. 67-76
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Tidskriftsartikel (refereegranskat)abstract
- The use of fluorescence and reflectance spectroscopy in the analysis of cervical histopathology is a growing field of research. The majority of this research is performed with point-like probes. Typically, clinicians select probe sites visually, collecting a handful of spectral samples. An exception to this methodology is the Hyperspectral Diagnostic Imaging (HSDI®) instrument developed by Science and Technology International. This non-invasive device collects contiguous hyperspectral images across the entire cervical portio. The high spatial and spectral resolution of the HSDI instruments make them uniquely well suited for addressing the issues of coupled spatial and spectral variability of tissues in vivo. Analysis of HSDI data indicates that tissue spectra vary from point to point, even within histopathologically homogeneous regions. This spectral variability exhibits both random and patterned components, implying that point monitoring may be susceptible to significant sources of noise and clutter inherent in the tissue. We have analyzed HSDI images from clinical CIN (cervical intraepithelial neoplasia) patients to quantify the spatial variability of fluorescence and reflectance spectra. This analysis shows the spatial structure of images to be fractal in nature, in both intensity and spectrum. These fractal tissue textures will limit the performance of any point-monitoring technology.
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| 8. |
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| 9. |
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| 10. |
- Johansson, Thomas, et al.
(författare)
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Feasibility study of a system for combined light dosimetry and interstitial photodynamic treatment of massive tumors
- 2002
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Ingår i: Applied Optics. - 2155-3165. ; 41:7, s. 1462-1468
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Tidskriftsartikel (refereegranskat)abstract
- A system for the photodynamic laser treatment of massive tumors that employs multiple optical fibers to be inserted into the tumor mass is described. The light flux through the tumor can be assessed by use of the individual fibers both as transmitters and as receivers. With a computer model that describes the diffusive light propagation, optical dosimetry is under development, The system has been tested in an experimental animal tumor model in preparation for clinical work. Currently, delta-aminolevulinic acid is used as a sensitizer, activated by 635-nm radiation from a 2.0-W compact diode laser system. With the availability of future, highly selective drugs absorbing approximately 750 nm, larger tumor volumes should be treatable, and surrounding, sensitive normal tissue should be spared.
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