Objectives: In this study, a treatment combining ethanol ablation (EA) and focused ultrasound (FUS) was performed to investigate its synergistic ablation effect on normal liver and VX2 liver tumours in rabbits.
Methods: A total of 59 healthy New Zealand white rabbits were included. For normal liver ablation, 39 animals were treated with FUS alone (n = 12), EA alone (n = 12), EA+FUS combination treatment (n = 12), or the control treatment (n = 3). The other 20 rabbits with implanted VX2 liver tumours were treated with EA alone (n = 10) or EA+FUS (n = 10). For FUS, the liver was exposed to 1 MHz FUS with an intensity of 33.0 W/cm2 (ISPTA) for 20 s. The EA group received an injection of absolute ethanol in the liver or liver tumours. For EA+FUS combination therapy, FUS was focused at the EA injection site, and both methods were carried out at the same time.
Results: In normal liver tissues, the ablated volume treated by FUS combined with EA (1.46 ± 0.30 cm3) was approximately 3 times larger than that of EA alone (0.51 ± 0.17 cm3); in VX2 liver tumours, the tumour necrosis rate of the combination therapy was 90.27%, which was much higher than that of EA treatment (63.55%).
Conclusion: The combination of EA and FUS could effectively increase the liver ablation volume and induce more complete tumour necrosis.
Key points: • This study demonstrated a novel method for enhancing ethanol ablation and elucidated its potential to enhance percutaneous ethanol ablation (PEA) in a simple non-invasive way. • Ethanol excited by focused ultrasound (FUS) exposure tended to accumulate at the injection site, which could prevent ethanol from being washed out by the bloodstream. • The combination of EA and FUS could effectively increase the liver ablation volume and induce more complete tumour necrosis.
Keywords: Ablation techniques; Ethanol; High-intensity focused ultrasound therapy; Liver neoplasms.