Preliminary Results: MR Guided Volumetric fflFU Ablation of Uterine Fibroids with Binary Feedback Control

This work presents the first clinical results of the treatment of uterine fibroids using a new volumetric high-intensity focused ultrasound (HIFU) ablation strategy. This treatment technique combines volumetric ablations using concentric circle trajectories with a binary feedback control algorithm. 13 patients have been treated so far with the proposed method with good results. The use of volumetric ablation increased the efficiency and speed of the treatment, while the binary feedback control ensured a reproducible thermal lesions size without prior knowledge of tissue specific parameters. The algorithm uses a simple and robust feedback control method that relies on rapid MR thermometry to control the HIFU exposure during the heating. The algorithm automatically modified the durations of the ablations to compensate for differences in the local ultrasound absorption and heat diffusion. This approach successfully produced consistent treated volumes with small deviations in the resulting lesion diameters. Four different trajectory sizes were used with diameters of 4 mm, 8 mm, 12 mm and 16 mm.