Comparison of fibre tips for percutaneous interstitial laser photocoagulation

This paper seeks to optimize the parameters of interstitial laser photocoagulation, and clarify controversies regarding the effect of three types of fibre tips used in percutaneous application on the size of thermal lesions produced.Bare-cut, pre-charred and conical diffused tips of 600 µm silica core fibre were compared using a diode laser (805 nm) applied in vitro using fresh porcine livers. Continuous wave laser radiation at 805 nm was applied at 1.0, 1.5, 2.0 and 2.5 W for 5, 10 and 15 min. The sizes of the resultant lesion, cavity and char were measured and analysed using the method of analysis of variance for statistical significance.It is concluded that the fibre tips do not significantly affect the lesion size (p> 0.05). Conical fibre tips produced less char when applied for 10 min or more at 2–2.5 W. Laser power and irradiation time affect the lesion size significantly (p< 0.05), and the size of the lesion produced depends on both laser power and irradiation time, not merely on the total laser energy applied.