Advanced Focused Ultrasound Surgery Treatment Planning
Focused ultrasound surgery (FUS) is a non-invasive treatment method. However, it is not without its obstacles, including the situation that bone or fat layers near an organ can cause refraction and reflection of the ultrasound, often leading to distortion of focal location, reduction of beam intensity, or even complete destruction of the focus. To get around these treatment obstacles, FUS investigators must use treatment planning methods to ensure that high powered ultrasound phased arrays correct for focal distortions.
The treatment planning method investigators are testing uses MR images to precisely calculate the power and phase of each array element to restore a focus. Specifically, the method uses MRI to develop a 3D representation of relevant tissue layers. Information is inputted into ultrasound propagation models that are being developing to rapidly determine the behavior of the ultrasound beam. Calculations are then made using the models to adjust the phased array to correct for distortions. Additionally, a calculated ultrasound field is used in a temperature simulation model to estimate tissue temperatures to eliminate pain and/or tissue damage at bone or gas interfaces beyond the focal spot.
To date, investigators have completed and tested an MR-compatible apparatus and finished optimization on tissue samples using a wave-vector time-domain linear propagation model. Additionally, they completed a through-transmission feasibility study for imaging the sound speed change in water induced by a thermal plume and the sound speed change in a phase contrast phantom. A near acoustically-transparent hydrophone was constructed along with the necessary signal filtering and amplification to allow acquisition of reflex transmission measurement.
Back to Research Projects.
Publications
- Farny C, Clement G. Feasibility of ultrasound phase contrast for heating localization. J Acoust Soc Am. 2008 Mar;123(3):1773-83. PMID: 18345865.
- Tang S, Clement G. A harmonic cancellation technique for an ultrasound transducer excited by a switched-mode power converter. IEEE Trans Ultrason Ferroelectr Freq Control. 2008 Feb;55(2):359-67. PMID: 18334342.
- Tang S, Clement G, Hynynen K. A computer-controlled ultrasound pulser-receiver system for transskull fluid detection using a shear wave transmission technique. IEEE Trans Ultrason Ferroelectr Freq Control. 2007 Sep;54(9):1772-83. PMID: 17941383.
- Clement G. Two-dimensional ultrasound detection with unfocused frequency-randomized signals. J Acoust Soc Am. 2007 Jan;121(1):636-47. PMID: 17297817.
- Hynynen K, Clement G. Clinical applications of focused ultrasound-the brain. Int J Hyperthermia. 2007 Mar;23(2):193-202. PMID: 17578343.
Involved Investigators
- Gregory Clement, PhD, NCIGT Core PI
- Phillip Jason White, PhD
- Caleb Farny, PhD