Acceleration of ultrasound thermal therapy by patterned acoustic droplet vaporization.
One application of acoustic droplet vaporization (ADV), a method of converting biocompatible microdroplets into microbubbles, is to enhance locally high intensity focused ultrasound (HIFU) therapy. Two objectives are pursued here: (1) the controlled creation of a bubble trench prior to HIFU using ADV and (2) use of the trench for increasing ablation volumes, lowering acoustic powers, and decreasing therapy duration. Thermally responsive phantoms were made with perfluorocarbon emulsion. Compound lesions were formed in a laboratory setting and a clinical magnetic resonance imaging (MRI)-guided HIFU system. Linear and spiral patterned compound lesions were generated in trenches. A larger fraction of the HIFU beam is contained to increase the generation of heat. Using the laboratory system, a 90 mm linear length spiral trench was formed in 30 s with mechanical beam steering. Comparatively, the clinical HIFU system formed a 19.9 mm linear length spiral trench in approximately 1 s with electronic beam steering. Lesions were imaged optically and with MRI. A uniform thermal ablation volume of 3.25 mL was achieved in 55.4 s (4-times faster than standard clinical HIFU and 14-times larger volume versus sum of individual lesions). Single lesions showed a 400% volume increase.
Department of Radiology, University of Michigan Health System, 1301 Catherine Street, Med Sci 1, Room 3218D, Ann Arbor, Michigan 48109-5667.
Oliver D
OD
Kripfgans
Department of Radiology, University of Michigan Health System, 1301 Catherine Street, Med Sci 1, Room 3218D, Ann Arbor, Michigan 48109-5667.
Man
M
Zhang
Department of Radiology, University of Michigan Health System, 1301 Catherine Street, Med Sci 1, Room 3218D, Ann Arbor, Michigan 48109-5667.
Mario L
ML
Fabiilli
Department of Radiology, University of Michigan Health System, 1301 Catherine Street, Med Sci 1, Room 3218D, Ann Arbor, Michigan 48109-5667.
Paul L
PL
Carson
Department of Radiology, University of Michigan Health System, 1301 Catherine Street, Med Sci 1, Room 3218D, Ann Arbor, Michigan 48109-5667.
Frederic
F
Padilla
Department of Radiology, University of Michigan Health System, 1301 Catherine Street, Med Sci 1, Room 3218D, Ann Arbor, Michigan 48109-5667.
Scott D
SD
Swanson
Department of Radiology, University of Michigan Health System, 1301 Catherine Street, Med Sci 1, Room 3218D, Ann Arbor, Michigan 48109-5667.
Charles
C
Mougenot
Department of Radiology, University of Michigan Health System, 1301 Catherine Street, Med Sci 1, Room 3218D, Ann Arbor, Michigan 48109-5667.
J Brian
JB
Fowlkes
Philips Healthcare, 281 Hilmount Road, Markham, Ontario L6C 2S3, Canada.
Charles
C
Mougenot
D003287:Contrast Media; D004655:Emulsions; D005466:Fluorocarbons; D057086:High-Intensity Focused Ultrasound Ablation / Q000379:methods*; D016014:Linear Models; D053783:Magnetic Resonance Imaging, Interventional / Q000295:instrumentation; D045423:Microbubbles; D009038:Motion; D019047:Phantoms, Imaging; D011312:Pressure; D013016:Sound; D013997:Time Factors; D014835:Volatilization
D003287:Contrast Media; D004655:Emulsions; D005466:Fluorocarbons