Noninvasive, Transient and Selective Blood-Brain Barrier Opening in Non-Human Primates In Vivo

The blood-brain barrier (BBB) is a specialized vascular system that impedes entry of all large and the vast majority of small molecules including the most potent central nervous system (CNS) disease therapeutic agents from entering from the lumen into the brain parenchyma. Microbubble-enhanced, focused ultrasound (ME-FUS) has been previously shown to disrupt noninvasively, selectively, and transiently the BBB in small animals in vivo. For the first time, the feasibility of transcranial ME-FUS BBB opening in non-human primates is demonstrated with subsequent BBB recovery. Sonications were combined with two different types of microbubbles (customized 4–5 µm and Definity®). 3T MRI was used to confirm the BBB disruption and to assess brain damage

A 63 element 1.75 dimensional ultrasound phased array for the treatment of benign prostatic hyperplasia

BACKGROUND: Prostate cancer and benign prostatic hyperplasia are very common diseases in older American men, thus having a reliable treatment modality for both diseases is of great importance. The currently used treating options, mainly surgical ones, have numerous complications, which include the many side effects that accompany such procedures, besides the invasive nature of such techniques. Focused ultrasound is a relatively new treating modality that is showing promising results in treating prostate cancer and benign prostatic hyperplasia. Thus this technique is gaining more attention in the past decade as a non-invasive method to treat both diseases. METHODS: In this paper, the design, construction and evaluation of a 1.75 dimensional ultrasound phased array to be used for treating prostate cancer and benign prostatic hyperplasia is presented. With this array, the position of the focus can be controlled by changing the electrical power and phase to the individual elements for electronically focusing and steering in a three dimensional volume. The array was designed with a maximum steering angle of ± 13.5° in the transverse direction and a maximum depth of penetration of 11 cm, which allows the treatment of large prostates. The transducer piezoelectric ceramic, matching layers and cable impedance have been designed for maximum power transfer to tissue. RESULTS: To verify the capability of the transducer for focusing and steering, exposimetry was performed and the results correlated well with the calculated field. Ex vivo experiments using bovine tissue were performed with various lesion sizes and indicated the capability of the transducer to ablate tissue using short sonications. CONCLUSION: A 1.75 dimensional array, that overcame the drawbacks associated with one-dimensional arrays, has been designed, built and successfully tested. Design issues, such as cable and ceramic capacitances, were taken into account when designing this array. The final prototype overcame also the problem of generating grating lobes at unwanted locations by tapering the array elements

Intermediate Range Wireless Power Transfer with Segmented Coil Transmitters for Implantable Heart Pumps

In wireless power transfer systems, substantial differences in transmission range and alignment sensitivity can occur when the transmitting coil dimensions are varied. A coil with larger inner and outer diameter was found to provide a wider transmission range and lower alignment sensitivity. Accordingly, we developed a larger coil (24×30 cm2) designed to be embedded in the back of a vest to power dc pumps for artificial hearts or left ventricular assist devices. To significantly reduce the required transmitting coil voltage, the coil was divided into eight segments with resonant capacitors. The coil was operated at 6.78 MHz and evaluated with a 5.3-cmdiameter receiving coil. A circuitmodel for the energy coupling coilswas developed to predict the output power and efficiency. Having a coil separation of 7.7 cm, we measured an output power of 48.2 W and a corresponding energy efficiency higher than 80%. The energy coupling coils were also evaluated with a dc pump in parallel to an additional load representing the power consumed by auxiliary circuits of an implanted heart pump. Experimental results showed that the proposed coil segmentation technique for mid-range wireless energy transfer can significantly reduce the transmitter voltage to a safe level (∼10 Vrms )

Potential of minimally invasive procedures in the treatment of uterine fibroids: a focus on magnetic resonance-guided focused ultrasound therapy

Krisztina Fischer,1–3 Nathan J McDannold,1 Clare M Tempany,1 Ferenc A Jolesz,1,† Fiona M Fennessy1,4 1Department of Radiology, 2Renal Division, 3Biomedical Engineering Division, Brigham and Women’s Hospital, 4Department of Radiology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA †Ferenc A Jolesz passed away on December 31, 2014 Abstract: Minimally invasive treatment options are an important part of the uterine fibroid-treatment arsenal, especially among younger patients and in those who plan future pregnancies. This article provides an overview of the currently available minimally invasive therapy options, with a special emphasis on a completely noninvasive option: magnetic resonance-guided focused ultrasound (MRgFUS). In this review, we describe the background of MRgFUS, the patient-selection criteria for MRgFUS, and how the procedure is performed. We summarize the published clinical trial results, and review the literature on pregnancy post-MRgFUS and on the cost-effectiveness of MRgFUS. Keywords: uterine fibroids, MRgFUS, focused ultrasound, minimally invasive treatment&nbsp

Mid-range wireless power transfer with segmented coil transmitters for implantable heart pumps

In wireless power transfer systems, the transmitting coil dimensions can substantially affect the transmission range and alignment sensitivity. We found that a transmitting coil with larger inner and outer diameter has a wider transmission range and lower alignment sensitivity. Thus, we developed a larger coil (24×30 cm2) designed to be embedded in the back of a vest to power DC pumps for artificial hearts or LVADs. To significantly reduce the required voltage, the coil was divided into 8 segments with resonant capacitors. The coil was operated at 6.78 MHz and evaluated with a 5.3-cm diameter receiving coil. A circuit model for the energy coupling coils was developed to predict the output power and efficiency. Having a coil separation of 7.7 cm, the output power and efficiency of the energy coupling coils are higher than 48 W and 80%, respectively. The system was experimentally tested with a DC pump, demonstrating that the proposed coil segmentation technique can significantly reduce the transmitter voltage to a safe level (~10 Vrms)