Sapphire probe versus bare fiber in interstitial laser hyperthermia (ILH). An experimental study with Wistar rats

The aim of this study was to compare the effects of a bare laser fiber and a contact sapphire probe on normal Wistar rat liver in interstitial laser hyperthermia (ILH). We used two different powers (1W and 2W) and eight different exposure times (50s to 900s). The livers were examined after 3 days and in the long-term follow-up group after 2 months. The greatest necrotic lesions were achieved with 600-900J energy (2W, 300-450s) using a bare laser fiber. The diameter of the necrotic lesions plateaued with 2W power setting after 300J energy. Generally, necrotic lesions were greater using a bare fiber than a sapphire probe with equal energy levels. The lesions healed by granulation and fibrosis. No scars or necrotic lesions were found 2 months after treatment when a 1W power setting was used, whereas a power of 2W caused a clear scar in the rat liver. ILH treatment caused necrosis safely and the bare fiber produced a greater necrotic area than the sapphire probe.