All ablations were performed under MR guidance on a Bruker BioSpec 7T small animal MR system (Bruker Biospin) with core body temperature monitoring using a 16-element annular array transducer operating at 3 MHz (Imasonic SAS)60. Acoustic pressure was calibrated with a fiber optic hydrophone (HFO690, Onda Corp.) in a degassed water tank under free-field conditions. Prior to ablation, mice were given 0.05–0.1 mg/kg buprenorphine subcutaneously (s.c.) and 0.05 mmol/kg gadoteridol (Bracco Imaging) i.p. and imaged with a T1w RARE (TE/TR = 12.5/750 ms, FOV = 4.8 cm × 4.8 cm, MTX = 256 × 256, ST/SI = 1/1 mm, 17 slices) sequence for tumor localization and treatment planning. Tumors were then ablated and temperature was monitored in real time via the MR proton resonance frequency shift using Thermoguide Software (Image Guided Therapy), with α = − 0.0101 ppm/°C, TE/TR = 4.5/21 ms5.

For thermal ablation, continuous wave (CW) insonation was employed at 3.1 MPa in a circular pattern (diameter of 2 mm, scan speed of 1 revolution per second) until the targeted volume reached at least 60 °C and a thermal dose in cumulative equivalent minutes at 43 degrees (CEM43) of more than 5000 was achieved15.

For mechanical ablation, tumors were ablated in a grid pattern with individual points separated by 0.5 mm, treating the entirety of the tumor with the exception of a ~ 0.5–0.75 mm rim. Each point of the grid pattern was insonated for 5 ms at 16.9 MPa (peak negative pressure), 95.3 MPa (peak positive pressure), with a duty cycle of 0.5%. The duty cycle was chosen to minimize thermal effects and maintain temperature elevations ≤ 2 °C. The grid pattern was repeated 10 times.

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