| 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
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Ingår i: Optical Biopsies and Microscopic Techniques, Proceedings of. - : SPIE. - 0819423289 ; 2926, s. 32-40
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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. |
- Andersson-Engels, Stefan, et al.
(författare)
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Autofluorescence of various rodent tissues and human skin tumour samples
- 1987
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Ingår i: Lasers in Medical Science. - 0268-8921. ; 2:1, s. 41-49
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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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| 3. |
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| 4. |
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| 5. |
- 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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| 6. |
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| 7. |
- Berg, Roger, et al.
(författare)
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Time-resolved tranillumination imaging
- 1993
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Ingår i: Medical Optical Tomography: Functional Imaging and Monitoring. ; , s. 397-424
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Bokkapitel (refereegranskat)
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| 8. |
- 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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| 9. |
- Krite Svanberg, Emilie, et al.
(författare)
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Diode laser spectroscopy for non-invasive monitoring of oxygen in the lungs of newborn infants.
- 2016
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Ingår i: Pediatric Research. - : Springer Science and Business Media LLC. - 1530-0447 .- 0031-3998. ; 79, s. 621-628
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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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| 10. |
- 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
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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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| 11. |
- Lundin, Patrik, et al.
(författare)
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Non-invasive gas monitoring in newborn infants using diode laser absorption spectroscopy: A case study
- 2012
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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
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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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| 12. |
- Lundin, Patrik, et al.
(författare)
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Noninvasive monitoring of gas in the lungs and intestines of newborn infants using diode lasers: feasibility study.
- 2013
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Ingår i: Journal of Biomedical Optics. - 1083-3668. ; 18:12
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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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| 13. |
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| 14. |
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| 15. |
- 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
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Ingår i: Translational Biophotonics. - : Wiley. - 2627-1850.
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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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| 16. |
- Stenberg, M, et al.
(författare)
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Interstitial photodynamic therapy - diagnostic measurements and treatment in rat malignant experimental tumours
- 2000
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Ingår i: OPTICAL BIOPSY AND TISSUE OPTICS. - : SPIE. - 1996-756X .- 0277-786X. - 0819438170 ; 4161:32, s. 151-157
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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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| 17. |
- Svanberg, Emilie Krite, et al.
(författare)
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Non-invasive monitoring of oxygen in the lungs of newborn infants using diode laser spectroscopy
- 2016
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Ingår i: Cancer Imaging and Therapy, CANCER 2016. - 9781943580101 ; Part F13-CANCER 2016
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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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| 18. |
- Svanberg, Katarina, et al.
(författare)
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Clinical multi-colour fluorescence imaging of malignant tumours - Initial experience
- 1998
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Ingår i: Acta Radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 39:1, s. 2-9
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The detection of malignant tumours relies on a variety of diagnostic procedures including X-ray images and, for hollow organs, endoscopy. The purpose of this study was to present a new technique for non-invasive tumour detection based on tissue fluorescence imaging. Material and Methods: A clinically adapted multi-colour fluorescence system was employed in the real-time imaging of malignant rumours of the skin, breast, head and neck region, and urinary bladder. Tumour detection was based on the contrast displayed in fluorescence between normal and malignant tissue, related to the selective uptake of tumour-marking agents, such as haematoporphyrin derivative (HPD) and Famine levulinic acid (ALA), and natural chromophore differences between various tissues. In order to demarcate basal cell carcinomas of the skin, ALA was applied topically 4-6 h before the fluorescence investigation. For urinary bladder tumour visualisation (transitional cell carcinoma of different stages including carcinoma in situ), ALA was instilled into the bladder 1-2 h prior to the study. Malignant and premalignant lesions in the head and neck region were imaged after i.v. injection of HPD (Photofrin). Finally, the extent of in situ and invasive carcinomas of the breast was investigated in surgically excised specimens from patients that received a low-dose injection of HPD 24 h prior to the study. The tumour imaging system was coupled to an endoscope. Fluorescence light emission from the tissue surface was induced with 100-ns-long optical pulses at 390 nm, generated from a frequency-doubled alexandrite laser. With the use of special image-splitting optics, the tumour fluorescence, intensified in a micro-channel plate, was imaged in 3 selected wavelength bands. These 3 images were processed together to form a new optimised-contrast image of the tumour. This image, updated at a rate of about 3 frames/s, was mixed with a normal colour video image of the tissue. Results: A clear demarcation from normal surrounding tissue was found during in vivo measurements of superficial bladder carcinoma, basal cell carcinoma of the skin, and leukoplakia with dysplasia of the lip, and in in vitro investigations of resected breast cancer. Conclusions: The initial clinical experience of using multi-colour fluorescence imaging has shown that the technique has the potential to reveal malignant tumour tissue, including non-invasive early carcinoma and also precancerous tissue. Further investigations are needed to fully develop the method.
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| 19. |
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| 20. |
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| 21. |
- 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
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Ingår i: Journal of Photochemistry and Photobiology, B: Biology. - 1011-1344. ; 49:2-3, s. 120-128
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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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| 22. |
- Alian, Wael A, 1970, et al.
(författare)
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Laser-induced fluorescence studies of meso-tetra(hydroxyphenyl)chlorin in malignant and normal tissues in rats.
- 1994
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Ingår i: British journal of cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 70:5, s. 880-5
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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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| 23. |
- Andersson-Engels, Stefan, et al.
(författare)
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Clinical fluorescence imaging
- 2008
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Ingår i: Lasers in Medicine.
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 24. |
- Andersson-Engels, Stefan, et al.
(författare)
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Clinical recording of laser-induced fluorescence spectra for evaluation of tumour demarcation feasibility in selected clinical specialities
- 1991
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Ingår i: Lasers in Medical Science. - 0268-8921. ; 6:4, s. 415-424
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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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| 25. |
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