Robert Staruch1,2, Melissa Togtema1,
Rajiv Chopra1,2, Kullervo Hynynen1,2
1Centre for Research in
Image-Guided Therapeutics, Sunnybrook Health Sciences Centre, Toronto,
Ontario, Canada; 2Department of Medical Biophysics, University of
Toronto, Toronto, Ontario, Canada
MRI-controlled focused ultrasound was used to generate mild hyperthermia at a soft tissue-bone interface in 5 rabbit thighs, for the purpose of achieving localized drug delivery with thermosensitive liposomes. FSPGR images perpendicular to the ultrasound beam were used for temperature control in muscle adjacent to bone. Median temperatures in a 10mm target were maintained at 43C for 20min. Muscle adjacent to heated bone had 18-fold higher drug concentrations as muscle adjacent to unheated bone. The results demonstrate the feasibility of MRI-controlled focused ultrasound hyperthermia at soft tissue-bone interfaces, and its potential for localized drug delivery with thermosensitive liposomes.