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Titolo:
Transpupillar laser phototherapy for retinal and choroidal tumors: A rational approach
Autore:
Rol, P; Fankhauser, F; Giger, H; Durr, U; Kwasniewska, S;
Indirizzi:
Lindenhofspital, CH-3017 Bern, Switzerland Lindenhofspital Bern Switzerland CH-3017 ital, CH-3017 Bern, Switzerland Univ Zurich, Dept Ophthalmol, CH-8091 Zurich, Switzerland Univ Zurich Zurich Switzerland CH-8091 lmol, CH-8091 Zurich, Switzerland Meridian AG, CH-3097 Bern, Switzerland Meridian AG Bern Switzerland CH-3097 idian AG, CH-3097 Bern, Switzerland
Titolo Testata:
GRAEFES ARCHIVE FOR CLINICAL AND EXPERIMENTAL OPHTHALMOLOGY
fascicolo: 3, volume: 238, anno: 2000,
pagine: 249 - 272
SICI:
0721-832X(200003)238:3<249:TLPFRA>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
PROTON-BEAM IRRADIATION; MALIGNANT UVEAL MELANOMA; OPTICAL PROPERTY CHANGES; INDIRECT OPHTHALMOSCOPE; INTRAOCULAR TUMORS; DELIVERY SYSTEMS; LIGHT-ABSORPTION; PHOTOCOAGULATION; TISSUE; ND;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Citazioni:
146
Recensione:
Indirizzi per estratti:
Indirizzo: Fankhauser, F Lindenhofspital, Bremgartenstr 117, CH-3017 Bern, Switzerland Lindenhofspital Bremgartenstr 117 Bern Switzerland CH-3017
Citazione:
P. Rol et al., "Transpupillar laser phototherapy for retinal and choroidal tumors: A rational approach", GR ARCH CL, 238(3), 2000, pp. 249-272

Abstract

Background: The physical laws are considered that need to be taken into account for optimal photothermal treatment of solid and vascular tumors, as well as other vascular anomalies of various etiology of the retina and choroid. Optimal irradiation therapy should take into account the distribution of both radiant and thermal energy in tumors, such as retinoblastomas, malignant melanomas and vascular malformations. Strict confinement of the extentof photothermal damage is critical since such pathological entities are frequently located close to the macula or optic nerve head. Methods: A formaltreatment of the optical quantities related to these requirements is presented. In this analysis we emphasize the following topics: Arrhenius' law, the kinetics of protein denaturation, the electromagnetic radiation field, wavelength, laser pulse duration (exposure time), optical properties of tissue, photocoagulation and thermotherapy. Results: Generally, the conditions are best fulfilled when using radiation in the near-infrared range of the electromagnetic spectrum, such as that emitted from the diode (810 nm) and Nd:YAG (1064 nm) laser, because of the good optical penetration properties of this radiation in tissue. The xenon are lamp was a very effective and particularly appropriate energy source for such purposes, and its withdrawal from the world market may have been untimely. Short wavelength sources of radiation, such as the argon ion (488, 514 nm) or the frequency-doubled Nd:YAG (532 nm) laser, are unsuitable for the irradiation of large vascular structures, as they have poor penetration depths. However, for vascular formations with a short path length (1 mm or less), short wavelength sources appear to be the most appropriate choicer Optical coupling of radiant energy to the eye by means of indirect ophthalmoscopic systems or contact lenses to the eye is crucial. Strong positive lenses may lead to severe constriction of the laser beam which leads to high irradiance within the anterior segment, increasing the chances of it being damaged; with negative contact lenses,such as the -64 D Goldmann type, this danger is reduced. Conclusions: Photothermotherapy is not without risk unless the temperature field can be welladapted to the tumorous structure, as temperature elevations outside a small therapeutic range that affect vital structures are considered to be a risk factor.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/11/20 alle ore 19:37:36