title: Protection of fiber function by para-axial fluid flow in interstitial laser therapy of malignant tumors.
abstract: In the past, interstitial laser therapy frequently has failed because of the damage to the bare fiber tip due to intense heat generated at the point of contact. Using a rat mammary tumor model, we describe a method of placing a 600 micron fiber inside a gauge 19 needle cannula after its insertion into the tumor. With this device continuous wave Nd:YAG laser is delivered to the target tumor while 0.9% saline flows para-axially into the tumor. Significant coagulation necrosis was induced with 500 joules at 5 watts, 100 seconds and 1 cc per minute of saline while the needle-fiber is pulled out of the tumor by 10 mm. The mean transmission loss after 500 joules was 2% in ten experiments. The tumor edema due to 1.5 ml of saline was transient. We conclude that successful hyperthermic coagulation necrosis by Nd:YAG laser can be achieved with minimal transmission loss by employing the above technique.
authors.affiliation: Department of General Surgery, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612.
authors.forename: K
authors.initials: K
authors.lastname: Dowlatshahi
authors.forename: J D
authors.initials: JD
authors.lastname: Bangert
authors.forename: M F
authors.initials: MF
authors.lastname: Haklin
authors.forename: C K
authors.initials: CK
authors.lastname: Rhodes
authors.forename: R S
authors.initials: RS
authors.lastname: Weinstein
authors.forename: S G
authors.initials: SG
authors.lastname: Economou
mesh_terms: D000818:Animals; D005260:Female; D006979:Hyperthermia, Induced / Q000295:instrumentation* / Q000379:methods; D053685:Laser Therapy; D008325:Mammary Neoplasms, Experimental / Q000628:therapy*; D051381:Rats; D011919:Rats, Inbred Strains