Image guided focused ultrasound: development of a comprehensive treatment planning, monitoring and control, and assessment
© Arvanitis et al; licensee BioMed Central Ltd. 2015
Published: 30 June 2015
MRgFUS offers unambiguous advantages over other current treatment modalities, as it is noninvasive and does not use ionizing radiation. Further, ultrasonically-controlled stable and inertial microbubble oscillations exert forces that can, among others, activate cell’s mechanoreceptors, disrupt cellular and vascular membranes, accelerate the dissolution of blood clots, enhance thermal ablation, and induce localized tissue erosionetc. FUS can also be used transcranially for tumor ablation, blood-brain barrier disruption, neuromodulation, etc. Harnessing and, potentially, combining these abilities holds great promise for therapy and diagnosis of cancer and cardiovascular and central nervous system diseases and disorders. For the wide-spread use of these approaches, development of methods and technology to enable precise planning, monitoring and control, and assessment of their outcome are essential.
Finally, using MR contrast agent as drug surrogate, the proposed framework is used to assess drug uptake after FUS-BBB disruption.
Results and conclusions
The incorporation of a variable speed of sound to the PAM back-projection algorithm corrected the aberrations introduced by the skull (NHP and Human). Further, more than 94% agreement in the FWHM of the axial and transverse line profiles between the simulations incorporating microbubble emissions and experimentally-determined PAMs was observed in NHP. The acoustic emissions monitoring allowed to fine-tune the sonication power for efficacious FUS-BBB disruption in glioma-bearing rat, while, MR temperature imaging based FUS controller allowed to attain constant focal temperature (temperature rise: 7±1.5 0C, for 5 mins) in the brain of a healthy rat. These abilities that have not been previously shown provide a clinically relevant framework for guiding FUS in the brain. We envision that the proposed framework will be essential for developing, optimizing, and translating current and new therapeutic FUS approaches to the clinics.
The authors would like to thank Dr Andriy Fedorov for his help with the software 3D Slicer and image registration. This work was supported by the NIH grants R25CA089017, P01CA174645, P41RR019703. InSightec provided the clinical TcMRgFUSsystem.
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