Protection of fiber function by para‐Axial fluid flow in interstitial laser therapy of malignant tumors

Kambiz Dowlatshahi, Julee D. Bangert, Michael F. Haklin, Charles K. Rhodes, Ronald S. Weinstein, Steven G. Economou

Research output: Contribution to journalArticle

26 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)322-327
Number of pages6
JournalLasers in Surgery and Medicine
Issue number4
StatePublished - 1990
Externally publishedYes



  • Nd:YAG laser fiber tip integrity
  • fluid pool
  • mammary tumor

ASJC Scopus subject areas

  • Surgery
  • Dermatology

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