| 1. |
- af Klinteberg, C, et al.
(författare)
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Laser-induced fluorescence diagnostics of basal cell carcinomas of the skin following topical ALA application
- 1996
-
Ingår i: Optical Biopsies and Microscopic Techniques, Proceedings of. - : SPIE. - 0819423289 ; 2926, s. 32-40
-
Konferensbidrag (refereegranskat)abstract
- Fourteen patients with superficial basal cell carcinomas (BCCs) and fifteen patients with nodular BCCs were investigated by means of laser-induced fluorescence (LIF) in connection with photodynamic therapy (PDT). Topical application of delta-amino levulinic acid (ALA) was performed six hours prior to the treatment session. Fluorescence spectra were recorded, using a point-monitoring system with an excitation wavelength of 405 nm. The measurements were performed in scans over the lesion and the surrounding normal skin before application of ALA, and immediately before and after the laser treatment. The selective uptake of the photosensitiser resulted in a fluorescence intensity ratio of 2.4:1 for superficial BCCs and 2.5:1 for nodular BCCs. If the fluorescence intensity was divided by the autofluorescence, this resulted in a contrast enhancement of about a factor 6 for tumour tissue. In seven patients (five with nodular BCC and two with superficial BCC), additional fluorescence measurements were performed two and four hours following the ALA application, and two hours after the PDT procedure. Thus, the kinetics of the transformation of ACA to protoporphyrin IX (PpIX) could be followed, which indicated that the synthesis of PpIX was more rapid in the tumour than in the normal tissue. After four hours, the PpIX level inside the tumour was saturated, while there still was an accumulation in the surrounding skin. The highest contrast between tumour and normal skin was reached within two hours after the ALA application.
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| 2. |
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| 3. |
- Stenberg, M, et al.
(författare)
-
Interstitial photodynamic therapy - diagnostic measurements and treatment in rat malignant experimental tumours
- 2000
-
Ingår i: OPTICAL BIOPSY AND TISSUE OPTICS. - : SPIE. - 1996-756X .- 0277-786X. - 0819438170 ; 4161:32, s. 151-157
-
Konferensbidrag (refereegranskat)abstract
- A recently developed multiple fibre system for treating malignant tumours with interstitial photodynamic therapy was used in studies on rats with colon adenocarcinoma inoculated into the muscles of the hind legs. The animals were intraperitonially administrated delta -aminolevulinic acid (ALA), which is metabolised to protoporphyrin IX (PpIX) in the tissue. The treatment system consists of a laser light source, a beam-splitting system dividing the light into three or six output fibres and a dosimetry programme calculating the optimal fibre position within the tumour as well as the treatment time needed to obtain a given threshold value of the light dose. One aim of the study was to compare the treatment outcome with the modelled dosimetry predictions. Tumour reduction was examined three days post treatment. A volume decrease was found in 85\% of the treated tumours. The mean volume reduction was 44\%, with one tumour completely disappearing. Histopathological examination three days post treatment showed substantial necrotic parts which, however, to a smaller extent were present also for non-treated tumours. These results indicated that the tumours have been under treated and the light dose has to be increased. Measurements of the build-up and photo-induced bleaching of PpIX using laser-induced fluorescence were also performed during the experiments.
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| 4. |
- Krite Svanberg, Emilie, et al.
(författare)
-
Diode laser spectroscopy for non-invasive monitoring of oxygen in the lungs of newborn infants.
- 2016
-
Ingår i: Pediatric Research. - : Springer Science and Business Media LLC. - 1530-0447 .- 0031-3998. ; 79, s. 621-628
-
Tidskriftsartikel (refereegranskat)abstract
- Newborn infants have pulmonary disorders with abnormal gas distribution, e. g. respiratory distress syndrome. Pulmonary radiography is the clinical routine for diagnosis. Our aim was to investigate a novel non-invasive optical technique for rapid non-radiographic bedside detection of oxygen gas in the lungs of full-term newborn infants.
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| 5. |
- Lundin, Patrik, et al.
(författare)
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Gas Monitoring in Human Body Cavities Using Non-Intrusive Diode Laser Absorption Spectroscopy
- 2012
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Ingår i: 2012 Asia Communications and Photonics Conference. - : IEEE. - 2162-108X. ; , s. 4-7
-
Konferensbidrag (refereegranskat)abstract
- Diode laser absorption spectroscopy was utilized for non-intrusive assessment of gas content in human body cavities, including intestines and lungs of a new-born, the mastoid bone, and sinus cavities for monitoring sinusitis recovery in adults.
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| 6. |
- Lundin, Patrik, et al.
(författare)
-
Non-invasive gas monitoring in newborn infants using diode laser absorption spectroscopy: A case study
- 2012
-
Ingår i: Optical Diagnostics and Sensing XII: Toward Point-of-Care Diagnostics; and Design and Performance Validation of Phantoms Used in Conjunction with Optical Measurement of Tissue IV. - : SPIE. - 1996-756X .- 0277-786X. ; 8229
-
Konferensbidrag (refereegranskat)abstract
- Non-invasive diode laser spectroscopy was, for the first time, used to assess gas content in the intestines and the lungs of a new-born, 4 kg, baby. Two gases, water vapor and oxygen, were studied with two low-power tunable diode lasers, illuminating the surface skin tissue and detecting the diffusely emerging light a few centimeters away. The light, having penetrated into the tissue, had experienced absorption by gas located in the lungs and in the intestines. Very distinct water vapor signals were obtained from the intestines while imprint from oxygen was lacking, as expected. Detectable, but minor, signals of water vapor were also obtained from the lungs, illuminating the armpit area and detecting below the collar bone. Water vapor signals were seen but again oxygen signals were lacking, now due to the difficulties of penetration of the oxygen probing light into the lungs of this full-term baby. Ultra-sound images were obtained both from the lungs and from the stomach of the baby. Based on dimensions and our experimental findings, we conclude, that for early pre-term babies, also oxygen should be detectable in the lungs, in addition to intestine and lung detection of water vapor. The present paper focuses on the studies of the intestines while the lung studies will be covered in a forthcoming paper.
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| 7. |
- Lundin, Patrik, et al.
(författare)
-
Noninvasive monitoring of gas in the lungs and intestines of newborn infants using diode lasers: feasibility study.
- 2013
-
Ingår i: Journal of Biomedical Optics. - 1083-3668. ; 18:12
-
Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT. Preterm newborn infants have a high morbidity rate. The most frequently affected organs where free gas is involved are the lungs and intestines. In respiratory distress syndrome, both hyperexpanded and atelectatic (collapsed) areas occur, and in necrotizing enterocolitis, intramural gas may appear in the intestine. Today, these conditions are diagnosed with x-ray radiography. A bed-side, rapid, nonintrusive, and gas-specific technique for in vivo gas sensing would improve diagnosis. We report the use of noninvasive laser spectroscopy, for the first time, to assess gas content in the lungs and intestines of three full-term infants. Water vapor and oxygen were studied with two low-power diode lasers, illuminating the skin and detecting light a few centimeters away. Water vapor was easily detected in the intestines and was also observed in the lungs. The relatively thick chest walls of the infants prevented detection of the weaker oxygen signal in this study. However, results from a previous phantom study, together with scaling of the results presented here to the typical chest-wall thickness of preterm infants, suggest that oxygen also should be detectable in their lungs.
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| 8. |
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| 9. |
- Sahlberg, Anna-Lena, et al.
(författare)
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Gas in Scattering Media Absorption Spectroscopy on Small and Large Scales: Towards the Extension of Lung Spectroscopic Monitoring to Adults
- 2021
-
Ingår i: Translational Biophotonics. - : Wiley. - 2627-1850.
-
Tidskriftsartikel (refereegranskat)abstract
- Numerous natural materials are porous, contain free gas, and are scattering light strongly. Scattering brings about a strong trapping of light and an associated prolonged transit time for photons through a medium. In contrast to the matrix materials, gas enclosures require very narrow‐band laser radiation for probing. We have in the present study used the gas in scattering media absorption spectroscopy (GASMAS) method to study free oxygen in thin (cm) samples utilizing a tunable diode laser, while a pulsed dye laser was employed in corresponding measurements on larger samples, up to the meter scale. Time‐resolved spectroscopy was in both cases used to assess the temporal distribution of the detected photons, mapping the path lengths through the media, which ranged between few centimeters up to 100 m. This study explores the feasibility to extend recent successful monitoring of gases in neonatal infant lungs to the case of larger children or even adults, which could have very important applications, for example, in ventilator setting optimization for severely ill patients, suffering, for example, from SARS‐CoV‐2. The conclusion of our work is that this goal most realistically can be reached by applying intra‐tracheal laser light illumination at the 1 W power level, employing a tapered amplifier, injected with a distributed feed‐back diode‐laser oscillator output and combined with wavelength‐modulation spectroscopy.
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| 10. |
- Svanberg, Emilie Krite, et al.
(författare)
-
Non-invasive monitoring of oxygen in the lungs of newborn infants using diode laser spectroscopy
- 2016
-
Ingår i: Cancer Imaging and Therapy, CANCER 2016. - 9781943580101 ; Part F13-CANCER 2016
-
Konferensbidrag (refereegranskat)abstract
- The main purpose of this study was to investigate a novel non-invasive optical technique for rapid bedside detection of oxygen gas in the lungs of full-term newborn infants. The results suggest that the technique will be clinically useful as a diagnostic and monitoring tool for infants with lung disorders.
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| 11. |
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| 12. |
- af Klinteberg, C, et al.
(författare)
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Kinetic fluorescence studies of 5-aminolaevulinic acid-induced protoporphyrin IX accumulation in basal cell carcinomas
- 1999
-
Ingår i: Journal of Photochemistry and Photobiology, B: Biology. - 1011-1344. ; 49:2-3, s. 120-128
-
Tidskriftsartikel (refereegranskat)abstract
- Laser-induced fluorescence (LIF) investigations have been performed in connection with photodynamic therapy (PDT) of basal cell carcinomas and adjacent normal skin following topical application of 5-aminolaevulinic acid (ALA) in order to study the kinetics of the protoporphyrin TX (PpIX) build-up. Five superficial and 10 nodular lesions in 15 patients are included in the study. Fluorescence measurements are performed prior to the application of ALA, 2, 4 and 6 h port ALA application, immediately post PDT (60 J cm(-2) at 635 nm), and 2 h after the treatment. Hence, the build-up, photobleaching and re-accumulation of PpIX can be followed. Superficial lesions show a maximum PpIX fluorescence 6 h post ALA application, whereas the intensity is already the highest 2-4 h after the application in nodular lesions. Immediately post PDT, the fluorescence contribution at 670 Mm from the photoproducts is about 2% of the pre-PDT PpIX fluorescence at 635 nm. Two hours after the treatment, a uniform distribution of PpIX is found in the lesion and surrounding normal tissue. During the whole procedure, the autofluorescence of the lesions and the normal skin does not vary significantly from the values recorded before the application of ALA. (C) 1999 Elsevier Science S.A. All rights reserved.
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| 13. |
- Alian, Wael A, 1970, et al.
(författare)
-
Laser-induced fluorescence studies of meso-tetra(hydroxyphenyl)chlorin in malignant and normal tissues in rats.
- 1994
-
Ingår i: British journal of cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 70:5, s. 880-5
-
Tidskriftsartikel (refereegranskat)abstract
- meso-Tetra(hydroxyphenyl)chlorin (mTHPC) is an attractive second-generation dihydroporphyrin photosensitiser for use in photodynamic therapy. In this study, 1.3 mg kg-1 body weight mTHPC was administered intravenously, and laser-induced fluorescence was used to characterise and compare its localisation and retention in different rat tissues, including an induced experimental adenocarcinoma, 24 h and 48 h post injection. These studies were performed in an attempt to predict the anatomical locations where mTHPC PDT might be most effective and suggest suitable injection--irradiation intervals in each case. Of particular interest were the intra-abdominal and intrathoracic tissues. The fluorescence was induced at 405 nm and the fluorescence spectrum in the region 450-750 nm was analysed. All collected spectra were dominated by the fluorescence signature of mTHPC with its peak at 652 nm, and all values in this study are in terms of background-free drug-specific fluorescence intensity at that wavelength. The photosensitiser accumulated in high concentrations in the tumour and the reticuloendothelial system. Muscular organs, such as the heart and the abdominal wall, were characterised by a low drug fluorescence signature.
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| 14. |
- Andersson-Engels, Stefan, et al.
(författare)
-
Autofluorescence of various rodent tissues and human skin tumour samples
- 1987
-
Ingår i: Lasers in Medical Science. - 0268-8921. ; 2:1, s. 41-49
-
Tidskriftsartikel (refereegranskat)abstract
- Fluorescence spectra from different organs in rats and mice have been recorded to explore the potential of non-intrusive tissue diagnostics. The fluorescence was induced by a nitrogen laser that emitted at a wavelength of 337 nm. Optical multichannel techniques were used for the detection. Spectra are given from 19 different sites in Wistar/Furth rats, including an inoculated malignant tumour. The spectra seem to be a sum of two wavelength distributions only, each distribution occurring with a different weight in different organs. Spectra obtained from living and dead tissue were compared to verify that the measurements on sacrificed experimental animals were valid. Preliminary results are given for some human tumours, transplanted in nude mice, and for some human skin samples.
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| 15. |
- Andersson-Engels, Stefan, et al.
(författare)
-
Clinical fluorescence imaging
- 2008
-
Ingår i: Lasers in Medicine.
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 16. |
- Andersson-Engels, Stefan, et al.
(författare)
-
Clinical recording of laser-induced fluorescence spectra for evaluation of tumour demarcation feasibility in selected clinical specialities
- 1991
-
Ingår i: Lasers in Medical Science. - 0268-8921. ; 6:4, s. 415-424
-
Tidskriftsartikel (refereegranskat)abstract
- Laser-induced autofluorescence spectra from humans were recorded in vivo at three different clinics in a study aimed at investigating the capability of this method to discriminate between malignant tumours and normal surrounding tissues. For the recordings a mobile trolley with the necessary equipment was constructed for use in an examination room or in an operating theatre environment. Laser light was guided through a 600m optical fibre to the target tissue. The fluorescence from the excited tissue was collected with the same fibre and was fed to an optical multichannel analyser. Two excitation wavelengths were used (337 and 405 nm) in order to optimize the fluorescence signals in two interesting wavelength regions (380–500 and 550–700 nm). Oral and oropharyngeal tumours excited with 405 nm light contained detectable endogenous porphyrins and were in this way discriminated from the normal mucosa. Astrocytoma grade III–IV fluorescence different from that of normal brain tissue, while tumours in the bronchial tree were not detectable using the spectral shape of the pure tissue autofluorescence.
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| 17. |
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| 18. |
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| 19. |
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| 20. |
- Andersson-Engels, Stefan, et al.
(författare)
-
Fluorescence Imaging and Point Measurements of Tissue - Applications To the Demarcation of Malignant-tumors and Atherosclerotic Lesions From Normal Tissue
- 1991
-
Ingår i: Photochemistry and Photobiology. - 0031-8655. ; 53:6, s. 807-814
-
Tidskriftsartikel (refereegranskat)abstract
- The possibilities of using laser-induced fluorescence for tissue diagnostics are discussed. The tissue types investigated are malignant tumors and atherosclerotic lesions. Studies with natural autofluorescence as well as with fluorescent tumor markers are included in this paper. Fluorescence emission and decay data are presented for some tissue chromophores contributing to tissue autofluorescence. Optical spectroscopic characteristics of fluorescent malignant tumor markers are analyzed and instrumental designs for clinical applications are discussed. Images recorded with a multicolor fluorescence imaging system developed in Lund are presented.
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| 21. |
- Andersson-Engels, Stefan, et al.
(författare)
-
Identification of brain tumours in rats using laser-induced fluorescence and haematoporphyrin derivative
- 1989
-
Ingår i: Lasers in Medical Science. - 0268-8921. ; 4:4, s. 241-249
-
Tidskriftsartikel (refereegranskat)abstract
- Laser-induced fluorescence has been used for the identification of brain tumours in rats, which have been previously given tumour-seeking haematoporphyrin derivative. A pulsed nitrogen laser (λ=337 nm) was used in conjunction with an optical multichannel analyzer. For both inoculated RG-2 and TCVC rat-brain-tumour models, the blue autofluorescence was strongly reduced in the tumour compared with normal brain tissue, and at the same time the characteristic red-drug signal increased. The contrast between tumour and normal tissue was strongly enhanced by forming the ratio between the two signals. Implications for possible improvement of tumour delineation in brain tumour surgery are discussed.
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| 22. |
- Andersson-Engels, Stefan, et al.
(författare)
-
In vivo fluorescence imaging for tissue diagnostics
- 1997
-
Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 1361-6560 .- 0031-9155. ; 42:5, s. 815-824
-
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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| 23. |
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| 24. |
- Andersson-Engels, Stefan, et al.
(författare)
-
Integrated system for interstitial photodynamic therapy
- 2003
-
Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 5142, s. 42-49
-
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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| 25. |
- Andersson-Engels, Stefan, et al.
(författare)
-
Integrated system for interstitial photodynamic therapy
- 2002
-
Ingår i: Advanced Optical Devices, Technologies, and Medical Applications. - : SPIE. - 0277-786X .- 1996-756X. ; 5123, s. 293-302
-
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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| 26. |
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| 27. |
- Andersson-Engels, Stefan, et al.
(författare)
-
Laser-induced Fluorescence In Malignant and Normal Tissue of Rats Injected With Benzoporphyrin Derivative
- 1993
-
Ingår i: Photochemistry and Photobiology. - : Wiley. - 0031-8655 .- 1751-1097. ; 57:6, s. 978-983
-
Tidskriftsartikel (refereegranskat)abstract
- Laser-induced fluorescence was used to characterize the localization of intravenously administered benzoporphyrin derivative-monoacid (BPD-MA) 3 h postinjection in different rat tissue types, including an induced experimental malignant tumor. A comparison of the fluorescence properties and the demarcation potential between the newer sensitizer BPD-MA and four other substances, hematoporphyrin (HP), polyhematoporphyrin ester (PHE), tetrasulfonated phthalocyanine (TSPc) and the commercially available Photofrin earlier investigated, is included. The fluorescence light was induced with a nitrogen laser, emitting at 337 nm. The fluorescence spectrum in the region 380-750 nm was analyzed by a polychromator equipped with a diode array detector. The demarcation potential between tumor and surrounding tissue in terms of fluorescence signal for the tumor model used was 2:1 for BPD-MA. In comparison with the other drugs, HP shows about the same demarcation potential, whereas Photofrin and PHE exhibit about 3 times better and TSPc about 1.5 times better demarcation. By also employing the endogenous tissue fluorescence signature the contrast was enhanced by a factor of about 2 for each of the five drugs.
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| 28. |
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| 29. |
- Andersson-Engels, Stefan, et al.
(författare)
-
Laser-induced fluorescence used in localizing atherosclerotic lesions
- 1989
-
Ingår i: Lasers in Medical Science. - 0268-8921. ; 4:3, s. 171-181
-
Tidskriftsartikel (refereegranskat)abstract
- We have investigated laser-induced fluorescence frompost mortem human arteries in order to find spectroscopic properties allowing discrimination between normal and atherosclerotic vessel wall. A pulsed nitrogen laser emitting light at a wavelength of 337.1 nm was used as an excitation source. The fluorescence spectrum from 370 to 700 nm was captured and analysed by an optical multichannel analyser. Dimensionless contrast functions were formed by using characteristic spectral features at 390, 415, 480, 580 and 600 nm. All samples were investigated in scans across a region where normal as well as diseased vessel wall appeared. The types of plaque were histopathologically divided into four groups, of which three could be singled out using one or more of our spectroscopic criteria. We also investigated the different layers of the normal and diseased vessel wall in order to determine the various contributions to the fluorescence signal. Furthermore, plasma emission spectra were recorded while ablating the normal as well as the diseased vessel wall with an excimer laser, emitting radiation at 308 nm, thus detecting the change in spectral characteristics during the ablation process down into deeper layers.
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| 30. |
- Andersson-Engels, Stefan, et al.
(författare)
-
Laser Spectroscopy in Medical Diagnostics
- 1992
-
Ingår i: Photodynamic Therapy: Basic Principles and Clinical Applications. - 0824786807 ; , s. 387-424
-
Bokkapitel (refereegranskat)
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| 31. |
- Andersson-Engels, Stefan, et al.
(författare)
-
Malignant-tumor and Atherosclerotic Plaque Diagnosis Using Laser-induced Fluorescence
- 1990
-
Ingår i: IEEE Journal of Quantum Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9197. ; 26:12, s. 2207-2217
-
Tidskriftsartikel (refereegranskat)abstract
- A review of tissue diagnostics using laser-induced fluorescence is given with illustrations chosen from work performed by the Lund group. Two major topics are considered: the demarcation of malignant tumors from normal surrounding tissue and the identification of atherosclerotic regions in arteries. Specific fluorescence from injected agents as well as tissue natural autofluorescence is discussed. Steady-state, as well as time-resolved fluorescence can be utilized. Furthurmore, original data showing immunity to blood interference in artery monitoring are presented. Finally, imaging techniques for diseased tissue real-time visualization are discussed and illustrated.
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| 32. |
- Andersson-Engels, Stefan, et al.
(författare)
-
Multi-colour fluorescence imaging in connection with photodynamic therapy of delta-amino levulinic acid (ALA) sensitised skin malignancies
- 1995
-
Ingår i: Bioimaging. - 0966-9051. ; 3:3, s. 134-143
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract A system for multi-colour fluorescence imaging of tissue is described. The instrument is mainly developed for tissue diagnostics to identify and localise malignant tumours, but might also be useful for real-time monitoring of the therapeutic dose delivered during photodynamic therapy. In vivo examples from various malignant skin lesions following topical δ-amino levulinic acid (ALA) administration are presented. The diagnostic system utilises both characteristics of a fluorescent tumour marker, such as a porphyrin containing substance, and the native tissue autofluorescence to characterise the tissue. A dimensionless function of three or four simultaneously recorded fluorescence intensities is formed and an optimum-contrast image is calculated pixel-by-pixel.
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| 33. |
- Andersson-Engels, Stefan, et al.
(författare)
-
Preliminary evaluation of two fluorescence imaging methods for the detection and the delineation of basal cell carcinomas of the skin
- 2000
-
Ingår i: Lasers in Surgery and Medicine. - 0196-8092. ; 26:1, s. 76-82
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract Background and ObjectiveFluorescence techniques can provide powerful noninvasive means for medical diagnosis, based on the detection of either endogenous or exogenous fluorophores. The fluorescence of δ-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) has already shown promise for the diagnosis of tumors. The aim of the study was to investigate the localization of skin tumors after the topical application of ALA, by detecting the PpIX fluorescence either in the spectral or in the time domain.Study Design/Materials and MethodsTwo fluorescence imaging systems were used to identify basal cell carcinomas of the skin in humans, after topical application of 20% ALA ointment. Both systems rely on the comparison between the exogenous and the endogenous fluorescence, performed either in the spectral domain or in the time domain. The first system works by using three images acquired through different spectral filters, whereas the second one measures the spatial map of the average fluorescence lifetime of the sample.ResultsA clear demarcation of skin malignancies was successfully performed in vivo noninvasively with both fluorescence imaging systems.ConclusionThe two complementary approaches considered in the present study show promise for skin tumor detection and delineation based on specific fluorescence features. Lasers Surg. Med. 26:76–82, 2000. © 2000 Wiley-Liss, Inc.
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| 34. |
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| 35. |
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| 36. |
- Andersson-Engels, Stefan, et al.
(författare)
-
Tumour marking properties of different haematoporphyrins and tetrasulfonated phthalocyanine - A comparison
- 1989
-
Ingår i: Lasers in Medical Science. - 0268-8921. ; 4:2, s. 115-123
-
Tidskriftsartikel (refereegranskat)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.
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| 37. |
- Andersson, Mats, et al.
(författare)
-
Laser spectroscopy of gas in scattering media at scales ranging from kilometers to millimeters
- 2007
-
Ingår i: Laser Physics. - 1054-660X. ; 17:7, s. 893-902
-
Tidskriftsartikel (refereegranskat)abstract
- Free gases are characterized by their narrow line width, and they can conveniently be studied by laser spectroscopy. The present paper discusses the monitoring of such ambient pressure gases, which are dispersed in scattering media such as aerosol-laden atmospheres, solids, or liquids. Atmospheric work basically constitutes the well-known field of differential absorption lidar (DIAL), while the study of free gas in solids and liquids was initiated more recently under the name of GASMAS (GAs in Scattering Media Absorption Spectroscopy). We discuss the connections between the two techniques, which are extensively used in our labortory. Thus, we span the field from trace-gas mapping of gases in the lower atmosphere to gas studies in construction materials, food products, and the human body. We show that the basic ideas are very similar, while the spatial and temporal scales vary greatly.
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| 38. |
- Andersson, S., et al.
(författare)
-
Tumour Localization by Means of Laser-Induced Fluorescence in Hematoporphyrin Derivative (HPD) — Bearing Tissue
- 1985
-
Ingår i: Laser Spectroscopy VII : Proceedings of the Seventh International Conference, Hawaii, June 24-28, 1985 - Proceedings of the Seventh International Conference, Hawaii, June 24-28, 1985. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 9783662152539 - 9783540396642 ; , s. 401-406
-
Konferensbidrag (refereegranskat)abstract
- Following systemic injection, hematoporphyrin derivative (HPD) is known to be selectively retained in malignant tissue. This property can be used in a two-fold way: a) for localizing tumours by observing the characteristic dual-peaked laser-induced fluorescence from HPD, and b) for photodynamic therapy (HPD-PDT) using a localized HPD-assisted singlet oxygen release induced by irradiation of 630 nm laser light. This rapidly developing field has recently been reviewed by DOUGHERTY.
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| 39. |
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| 40. |
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| 41. |
- Ankerst, J, et al.
(författare)
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Laser-induced Fluorescence Studies of Hematoporphyrin Derivative (hpd) In Normal and Tumor-tissue of Rat
- 1984
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Ingår i: Applied Spectroscopy. - : SAGE Publications. - 1943-3530 .- 0003-7028. ; 38:6, s. 890-896
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Tidskriftsartikel (refereegranskat)abstract
- Fluorescence studies of hematoporphyrin derivative (HPD) in normal and tumor tissue of rat were performed with nitrogen laser excitation and optical multi-channel detection. Fifteen types of tissue including inoculated tumor were investigated for rats at different delays after HPD injection. Optimum contrast functions and other criteria for discriminating tumor tissue from normal tissue are discussed. The results should have implications for practical human HPD endoscopy.
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| 42. |
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| 43. |
- Baert, L, et al.
(författare)
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Clinical Fluorescence Diagnosis of Human Bladder-carcinoma Following Low-dose Photofrin Injection
- 1993
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Ingår i: Urology. - : Elsevier BV. - 1527-9995 .- 0090-4295. ; 41:4, s. 322-330
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Tidskriftsartikel (refereegranskat)abstract
- A point-monitoring fluorescence diagnostic system based on a low-energy pulsed laser, fiber transmission optics, and an optical multichannel analyzer was used for diagnosis of patients with bladder malignancies. Twenty-four patients with bladder carcinoma, carcinoma in situ, and/or dysplasia were injected with hematoporphyrin derivative, Photofrin, 0.35 or 0.5 mg/kg body weight, forty-eight hours prior to the investigation. The ratio between the red sensitizer emission and the bluish tissue autofluorescence provided excellent demarcation between papillary tumors and normal bladder wall. Certain cases of dysplasia also could be differentiated from normal mucosa. Benign exophytic lesions such as malakoplakia appeared different from malignant tumors in fluorescence. Flat suspicious bladder mucosa such as seen in infectious diseases or after radiation therapy appeared normal on fluorescence.
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| 44. |
- Bendsoe, Niels, et al.
(författare)
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Fluorescence monitoring of a topically applied liposomal temoporfin formulation and photodynamic therapy of nonpigmented skin malignancies.
- 2007
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Ingår i: Journal of Environmental Pathology and Toxicology. - 2162-6537. ; 26:2, s. 117-126
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Tidskriftsartikel (refereegranskat)abstract
- Meso-tetra(hydroxyphenyl)chlorin (mTHPC) (INN: Temoporfin) is a potent photodynamically active substance in clinical use today. Usually, the substance is given systemically and a known drawback with this administration route is a prolonged skin light sensitization. For the first time to our knowledge, a liposomal Temoporfin gel formulation for topical application was studied in connection with photodynamic therapy (PDT) of nonpigmented skin malignancies in humans. Intervals of 4 hr between drug administration and light irradiation were used. Sensitizer distribution within tumor and surrounding normal skin was investigated by means of point monitoring and imaging fluorescence spectroscopy before, during, and after PDT, showing high tumor selectivity. Furthermore, the bleaching of Temoporfin was studied during the PDT procedure by monitoring the fluorescence following excitation by using a therapeutic light. A 30−35% light-induced photometabolization was shown. No pain occurred during or after treatment. It was also observed that the treated area did not show any swollen tissue or reddening, as is often seen in PDT using topical δ-aminolevulinic acid. On controlling the patients one week after treatment, healing progress was observed in several patients and no complications were registered.
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| 45. |
- Brydegaard, Mikkel, et al.
(författare)
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Complete parameterization of temporally and spectrally resolved laser induced fluorescence data with applications in bio-photonics
- 2015
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Ingår i: Chemometrics and Intelligent Laboratory Systems. - : Elsevier BV. - 0169-7439. ; 142, s. 95-106
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Tidskriftsartikel (refereegranskat)abstract
- We present a set of spectrally and temporally resolved clinical fluorescence data-with two separate excitation wavelengths-that was recorded in vivo. We demonstrate that data in the spectral and temporal domains are in certain ways coupled and provide a method for integrated and effective parameterization of spectrally and temporally resolved fluorescence (i.e., time-resolved emission spectra). This parameterization is based on linear algebra, matrix formulation and system identification. We demonstrate how to empirically extract single exponentially decaying components and provide rectified emission spectra without prior knowledge. We investigate the potential for improved cancer diagnostics according to the reduced parameters along the various domains. In this case, in terms of cancer diagnostics, we were unable to identify any benefits of simultaneously measuring both the temporal and spectral properties of the observed fluorescence. However, we note that this may be explained by an important experimental bias present in many studies of optical cancer diagnostics, namely, that, in general, suspected lesions always differ visually from the neighboring healthy tissue. (C) 2015 Elsevier B.V. All rights reserved.
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| 46. |
- Chen, Delong, et al.
(författare)
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Laser-based gas absorption spectroscopy in decaying hip bone : water vapor as a predictor of osteonecrosis
- 2019
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Ingår i: Journal of Biomedical Optics. - 1083-3668. ; 24:6, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- Affluent blood flow through a complicated net of vessels supplies skeletal bone tissue with oxygen and nutrients. Due to accidental events or physiological processes, the blood supply might be deficient or even disrupted, and the healthy bone decays in a process that, for the hip location, is denoted as osteonecrosis of the femoral head (ONFH) or avascular femoral head necrosis. Early diagnosis is important for the prognosis. X-ray-based imaging, such as CT or MRI, is not of much value for the early detection. As the decay theoretically is associated with the development of gas-filled pores, gas analysis should have diagnostic value. We have introduced gas in scattering media absorption spectroscopy, as a complementary modality. Eighteen extracted femoral joint heads, diseased as well as normal, were investigated. Diseased samples are associated with clear signals due to water vapor, whereas the normal ones largely lack such features. The results suggest that free water vapor could serve as an early indicator of pore development and thus as a promising predictor of ONFH pathological changes, once the technique has been fully refined.
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| 47. |
- Chen, Peng, et al.
(författare)
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Assessment of Free Gas in the Tibial Condyle Bone of the Human Knee by Diode Laser Spectroscopy with Possible Application to Arthrosis Diagnostics
- 2019
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - 0792-1233. ; 25:1
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Tidskriftsartikel (refereegranskat)abstract
- The gas in scattering media absorption spectroscopy (GASMAS) technique was used to investigate the possible presence of free gas pores in human condyle bones, extracted from the tibia in knee revision surgical procedures in response to arthrosis development. Following earlier studies showing free gas presence in femoral head bones, decaying because of inadequate blood flow, we investigated condyle bone, where the arthrosis degeneration process, affecting the cartilage cup, is of different origin. Only a minor gas presence was observed in affected condyle samples, in accordance with our finding for non-arthrosis samples. Further, studies of fresh or initially frozen samples showed very similar signals, suggesting that the handling procedure has only a minor importance in these studies. In contrast to the situation for femoral heads, the monitoring of a gas presence would add only little in assessing the arthrosis status in the view of elective surgical procedures.
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| 48. |
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| 49. |
- 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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| 50. |
- Eker, C, et al.
(författare)
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Clinical spectral characterisation of colonic mucosal lesions using autofluorescence and delta aminolevulinic acid sensitisation
- 1999
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Ingår i: Gut. - : BMJ. - 1468-3288 .- 0017-5749. ; 44:4, s. 511-518
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims-Laser induced fluorescence (LIF) from colonic mucosa was measured in vivo with and without delta aminolevulinic acid (ALA) in an attempt to differentiate between neoplasia and non-neoplasia in real time during colonoscopy. Methods-Spectra from 32 adenomas, 68 normal sites, and 14 hyperplastic polyps in 41 patients were obtained with a point monitoring system. Twenty one of the patients had been given a low dose of ALA as a photosensitiser before the examination. Light of 337, 405, or 436 nm wavelength was used as excitation. Stepwise multivariate Linear regression analysis was performed. Results-With 337 nm excitation, 100% sensitivity and 96% specificity was obtained between normal mucosa and adenomas. Seventy seven per cent of the hyperplastic polyps were classified as non-neoplastic. When exciting with 405 and 436 nm, the possibility of distinguishing different types of tissue was considerably better in the ALA patients than in the non-ALA patients. Conclusions-The in vivo point measurements imply that a good discrimination between normal tissue and adenomatous polyps can be obtained using the LIF technique. Excitation at 337 nm and at 405 nm or 436 nm using ALA gives good results. LIF also shows potential for distinguishing adenomatous from hyperplastic polyps. The number of detection wavelengths could be reduced if chosen properly.
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