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Dependence of laser photocoagulation on interstitial delivery parameters
Author(s) -
Wyman Douglas,
Wilson Brian,
Adams Kathryn
Publication year - 1994
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/lsm.1900140113
Subject(s) - laser , delivery system , medicine , ophthalmology , biomedical engineering , optics , physics
Photocoagulation was performed ex vivo between tissue slabs by delivering continuous‐wave laser energy from an optical fiber either directly, or by depositing the energy into a 2.4 mm diameter steel sphere at the fiber tip. The dependence of photocoagulation lesions on the following variables was assessed: (1) energy source: Nd:YAG‐532 nm, 1,064 nm ± steel sphere, (2) tissue type : porcine muscle (light), bovine muscle (dark), (3) delivered power : P = 1.5–3.0 W (porcine), 1.0–2.5 W (bovine), (4) exposure duration : T = 300–1500 s. The resulting cross‐sectional photocoagulation lesions are summarized as follows: 532 nm : elongated; central charring in all cases; 1,064 nm : circular; central charring only in bovine for P ⩾ 2.0 W, T ⩾ 500 s; sphere : circular; central charring in bovine for P ⩾ 1.5 W and porcine for P ⩾ 2.0 W. These experiments suggest photocoagulation lesion size decreases as optical penetration increases. The results indicate that interstitial laser photocoagulation lesions >10 mm diameter can be made without charring in both lightly and heavily pigmented tissues ex vivo by delivering 1,064 nm laser energy at sufficiently low power for at least 1,000 s from well‐polished optical fibers. © 1994 Wiley‐Liss, Inc.