title: Intracranial dual-mode IVUS and hyperthermia using circular arrays: preliminary experiments.
abstract: In this study, we investigated the feasibility of using 3.5-Fr (3 Fr = 1 mm) circular phased-array intravascular ultrasound (IVUS) catheters for minimally invasive, image-guided hyperthermia treatment of tumors in the brain. Feasibility was demonstrated in two ways: (1) by inserting a 3.5-Fr IVUS catheter through skull burr holes, for 20 MHz brain imaging in the pig model, and (2) by testing a modified circular array for therapy potential with 18.5-MHz and 9-MHz continuous wave (CW) excitation. The imaging transducer's performance was superior to our previous 9-MHz mechanical IVUS prototype. The therapy catheter transducer was driven by CW electrical power at 18.5 MHz, achieving temperature changes reaching +8°C at a depth of 2 mm in a human glioblastoma grown on the flank of a mouse with minimal transducer resistive heating of +2°C. Further hyperthermia trials showed that 9-MHz CW excitation produced temperature changes of +4.5°C at a depth of 12 mm-a sufficient temperature rise for our long-term goal of targeted, controlled drug release via thermosensitive liposomes for therapeutic treatment of 1-cm-diameter glioblastomas.
authors.affiliation: Duke University, Durham, NC, USA.
authors.forename: Vivek
authors.initials: V
authors.lastname: Patel
authors.forename: Edward
authors.initials: E
authors.lastname: Light
authors.forename: Carl
authors.initials: C
authors.lastname: Herickhoff
authors.forename: Gerald
authors.initials: G
authors.lastname: Grant
authors.forename: Gavin
authors.initials: G
authors.lastname: Britz
authors.forename: Christy
authors.initials: C
authors.lastname: Wilson
authors.forename: Mark
authors.initials: M
authors.lastname: Palmeri
authors.forename: Stephen
authors.initials: S
authors.lastname: Smith
mesh_terms: D000818:Animals; D001932:Brain Neoplasms / Q000628:therapy*; D057785:Catheters; D004867:Equipment Design; D005240:Feasibility Studies; D006979:Hyperthermia, Induced / Q000379:methods*; D019047:Phantoms, Imaging; D058226:Plaque, Atherosclerotic; D025321:Surgery, Computer-Assisted / Q000295:instrumentation; D013552:Swine; D014159:Transducers; D018084:Ultrasonography, Interventional / Q000295:instrumentation* / Q000379:methods