title: Suitability of a tumour-mimicking material for the evaluation of high-intensity focused ultrasound ablation under magnetic resonance guidance.
abstract: This study tests the suitability of a tumour-mimic for targeting magnetic resonance (MR)-guided high-intensity focused ultrasound (HIFU). An agarose-based tumour-mimic was injected as a warm solution that polymerized in tissue. Thermal characteristics and acoustic absorption of the mimic were observed within the values reported for tissues. The relaxation times at 3T were 1679 ± 15 ms for T1 and 41 ± 1 ms for T2. The mimic was clearly visible on in vivo images. With lower contrast the tumour-mimic was visible on T2-weighted images, where it was possible to detect the ablated tissue surrounding the mimic after sonications. HIFU sonications were performed to induce thermal ablation on and around the mimic using a Sonalleve system (Philips). MR thermometry maps were performed during HIFU. The average temperature when the sonication was done at the tumour-mimic was 67.6 ± 8.0 °C in vitro and 67.6 ± 5.0 °C in vivo. The average temperature for sonications at tissues was 68.4 ± 8.7 °C in vitro (liver) and 66.0 ± 2.6 °C in vivo (muscle), with no significant difference between tissue and tumour-mimic (p > 0.05). The tumour-mimic behaviour when using MR-guided HIFU was similar to tissues, showing that this mimic can be used as an alternative to tumour models for validating MR-guided HIFU devices targeting.
authors.affiliation: Thunder Bay Regional Research Institute; Electrical Engineering, Lakehead University, Thunder Bay, ON, Canada. spichard@lakeheadu.ca
authors.forename: S
authors.initials: S
authors.lastname: Pichardo
authors.forename: J
authors.initials: J
authors.lastname: Kivinen
authors.forename: D
authors.initials: D
authors.lastname: Melodelima
authors.forename: L
authors.initials: L
authors.lastname: Curiel
mesh_terms: D000042:Absorption; D000818:Animals; D002417:Cattle; D057086:High-Intensity Focused Ultrasound Ablation / Q000295:instrumentation*; D008099:Liver; D008279:Magnetic Resonance Imaging; D009369:Neoplasms / Q000601:surgery*; D019047:Phantoms, Imaging; D011817:Rabbits; D025321:Surgery, Computer-Assisted / Q000295:instrumentation*; D013696:Temperature