| 1. |
- Andersson-Engels, S., et al.
(författare)
-
Tissue diagnostics using laser-induced fluorescence
- 1989
-
Ingår i: Berichte der Bunsengesellschaft für Physikalische Chemie. - : Wiley. - 0005-9021. ; 93:3, s. 335-342
-
Tidskriftsartikel (refereegranskat)abstract
- We have performed extensive investigations of laser-induced fluorescence in animal and human tissue aimed at instant tissue characterization. Autofluorescence, as well as specific fluorescence from HPD/DHE and other photosensitizers, has been utilized. The studies have been focused on the demarcation of malignant tumours and atheroscleortic plaques. A nitrogen laser or an excimer-pumped dye laser was used to induce fluorescence, which was analysed with an intensified optical multichannel system. A fibre-optic sensor system was developed for the clinical work. Multi-colour fluorescence imaging has also been demonstrated along a line and equipment for two-dimensional imaging is being constructed. Dimensionless spectroscopic functions, which are not affected by factors that are clinically uncontrollable have been employed for optimum tissue discrimination. The investigations have so far been performed in a time-integrated mode, but time-resolved studies are now being initiated to fully exploit the diagnostic power of tissue laser-induced fluorescence. In addition to a presentation of our own work a brief review of tissue fluorescence studies performed by other groups is also given.
|
|
| 2. |
|
|
| 3. |
- Wide-Swensson, Dag, et al.
(författare)
-
Effect of methyldopa and isradipine on fetal heart rate pattern assessed by computerized cardiotocography in human pregnancy
- 1993
-
Ingår i: American Journal of Obstetrics and Gynecology. - 1097-6868. ; 169:6, s. 1581-1585
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The effects of two antihypertensive drugs, methyldopa and isradipine, on fetal heart rate pattern were analyzed by computerized cardiotocography. STUDY DESIGN: The first part of the study was a prospective, randomized, controlled trial of 19 women with preeclampsia in the third trimester given 2.5 mg of oral slow-release isradipine twice a day or 250 mg of methyldopa three times a day. In a second part of the study 23 women with preeclampsia in the third trimester given 5 mg of oral slow-release isradipine twice a day were compared with 23 matched controls without medication. Main outcome measures were maternal blood pressure and mean baseline fetal heart rate, fetal movements, number of accelerations, periods of high and low baseline variability, and mean baseline heart rate variability. RESULTS: Compared with the pretreatment value, the mean arterial blood pressure decreased significantly in all drug treatment groups. Fetal heart rate characteristics were not significantly changed during drug treatment or bed rest. CONCLUSION: The various features of the fetal heart rate pattern evaluated by computerized methods were not influenced by treatment with methyldopa or isradipine.
|
|
| 4. |
- Andersson-Engels, S., et al.
(författare)
-
Aspects of tumour demarcation in rats by means of laser-induced fluorescence and haematoporphyrin derivatives
- 1988
-
Ingår i: Lasers in Medical Science. - 0268-8921. ; 3:239, s. 239-248
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of different parameters of interest for the localization of malignant tumours in situ by means of laser-induced fluorescence and haematoporphyrin derivatives were investigated. Such parameters are drug composition, drug concentration, laser pulse energy and excitation wavelength. In order to assess the relative merits of the two tumour-seeking agents Photofrin (haematoporphyrin derivative) and Photofrin II (dihaematoporphyrin ether) we have performed a comparative study on rat tissues. The results suggest that Photofrin is at least as good as the therapeutically more potent agent Photofrin II. A linear relation between drug dose and recorded porphyrin fluorescence intensity was also found. Using not only the porphyrin fluorescence, but also natural tissue autofluorescence, better tumour demarcation is observed when utilizing an excitation wavelength shorter than the porphyrin excitation peak at 405 nm.
|
|
| 5. |
|
|
| 6. |
- Andersson, P. S., et al.
(författare)
-
TISSUE CHARACTERIZATION USING LASER-INDUCED FLUORESCENCE.
- 1987
-
Ingår i: Conference on Lasers and Electro-Optics. - 0936659491 ; 14, s. 46-48
-
Konferensbidrag (refereegranskat)abstract
- In cancer tumor detection, tissue autofluorescence and characteristic features of injected hematoporphyrin derivative (HPD) can be utilized. The authors have studied the importance of the excitation wavelength for the achievable contrast between tumor and surrounding tissue using a rat tumor model. They have also compared the relative merits of two HPD preparations for tumor fluorescence detection. The real-time capability of the fluorescence technique is discussed.
|
|
| 7. |
- 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.
|
|
| 8. |
- Ankerst, J., et al.
(författare)
-
SPECTRAL CHARACTERISTICS IN TISSUE DIAGNOSTICS USING LASER-INDUCED FLUORESCENCE.
- 1985
-
Ingår i: Proceedings of the Medicine & Biology Symposium, ICALEO '84. - 0912035250 ; 43-48, s. 52-60
-
Konferensbidrag (refereegranskat)abstract
- Studies of laser-induced fluorescence in rat tissues, including cancer tumors have been performed. Contrast enhancement techniques have been developed which improve the ability to localize a tumor when using fluorescence from the tumor-seeking substance hematoporphyrin derivative (HPD). A multi-color fluorescence imaging technique has been tested. A discussion of clinical applications is included.
|
|
| 9. |
- Svanberg, Katarina, et al.
(författare)
-
Clinical multi-colour fluorescence imaging of malignant tumours - Initial experience
- 1998
-
Ingår i: Acta Radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 39:1, s. 2-9
-
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.
|
|
| 10. |
|
|
