Improved coagulation with saline solution pretreatment during radiofrequency tumor ablation in a canine model

Muneeb Ahmed, S. Melvyn Lobo, Joseph Weinstein, Jonathan B. Kruskal, G. Scott Gazelle, Elkan F. Halpern, S. Karim Afzal, Robert E. Lenkinski, S. Nahum Goldberg

Research output: Contribution to journalArticlepeer-review

82 Scopus citations


PURPOSE: To determine whether pretreatment with local NaCl injection can increase radiofrequency (RF)-induced coagulation in a large animal model. MATERIAL AND METHODS: Multiple canine venereal sarcomas (n = 25) were implanted subcutaneously in eight mildly immunosuppressed dogs (25 mg/kg cyclosporin A twice daily). Tumors were incubated for 8-12 weeks to a diameter of 4.2-6.3 cm (5.1 cm ± 0.7). Internally cooled RF ablation (1-cm tip; 12 min; pulsed technique; 2,000-mA maximum) was performed. Tumors were pretreated with 6 mL of 18%, 24%, or 36% NaCl injected intratumorally under direct ultrasound guidance after RF electrode insertion, and this treatment was compared to RF treatment without NaCl injection and to 36% NaCl injection without RF ablation. Impedance measurements and remote thermometry were performed. These measurements and resultant coagulation were compared. RESULTS: Significantly greater RF heating (73°C ± 11°C at 20 mm) was observed when the tumors were treated with 24% or 36% NaCl pretreatment, compared to the 47°C ± 5°C observed when 18% or no NaCl was injected (P < .02). In the 36% NaCl group, the entire tumor (5.2 cm ± 0.8 diameter) was completely ablated in every case, with coagulation extending several centimeters into the surrounding tissues. By comparison, control tumors (without NaCl injection) contained coagulation measuring 3.1 cm ± 0.2, surrounded by viable, well-perfused tumor (P < .01), and 36% NaCl alone produced 2.7 cm ± 0.6 of patchy necrosis. CONCLUSIONS: Pretreatment with intratumoral injection of small volumes of highly concentrated NaCl markedly increases RF heating and coagulation in a large animal tumor model. The complete destruction of tumors 5 cm in diameter or larger suggests that this substantial increase may be achieved for tumor ablation in clinical practice.

Original languageEnglish (US)
Pages (from-to)717-724
Number of pages8
JournalJournal of Vascular and Interventional Radiology
Issue number7
StatePublished - Jul 2002


  • Neoplasms, therapy
  • Radiofrequency (RF) ablation

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Cardiology and Cardiovascular Medicine


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