title: Pre-clinical testing of a phased array ultrasound system for MRI-guided noninvasive surgery of the brain--a primate study.
abstract: MRI-guided and monitored focused ultrasound thermal surgery of brain through intact skull was tested in three rhesus monkeys. The aim of this study was to determine the amount of skull heating in an animal model with a head shape similar to that of a human. The ultrasound beam was generated by a 512 channel phased array system (Exablate 3000, InSightec, Haifa, Israel) that was integrated within a 1.5-T MR-scanner. The skin was pre-cooled by degassed temperature controlled water circulating between the array surface and the skin. Skull surface temperature was measured with invasive thermocouple probes. The results showed that by applying surface cooling the skin and skull surface can be protected, and that the brain surface temperature becomes the limiting factor. The MRI thermometry was shown to be useful in detecting the tissue temperature distribution next to the bone, and it should be used to monitor the brain surface temperature. The acoustic intensity values during the 20 s sonications were adequate for thermal ablation in the human brain provided that surface cooling is used.
authors.affiliation: Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA. kullervo@bwh.harvard.edu
authors.forename: Kullervo
authors.initials: K
authors.lastname: Hynynen
authors.forename: Nathan
authors.initials: N
authors.lastname: McDannold
authors.forename: Greg
authors.initials: G
authors.lastname: Clement
authors.forename: Ferenc A
authors.initials: FA
authors.lastname: Jolesz
authors.forename: Eyal
authors.initials: E
authors.lastname: Zadicario
authors.forename: Ron
authors.initials: R
authors.lastname: Killiany
authors.forename: Tara
authors.initials: T
authors.lastname: Moore
authors.forename: Douglas
authors.initials: D
authors.lastname: Rosen
mesh_terms: D000818:Animals; D001831:Body Temperature; D001921:Brain / Q000601:surgery*; D006358:Hot Temperature; D008253:Macaca mulatta; D008279:Magnetic Resonance Imaging; D023421:Models, Animal; D013821:Thermometers; D014464:Ultrasonic Therapy / Q000295:instrumentation / Q000379:methods*