Paul Jaeger

Peripheral ultrasound imaging system

A peripheral ultrasound imaging system for connection to a personal computing device or a computer network which enables real time ultrasound imaging without additional modules and without the need to modify, augment or replace the existing central processing unit. The peripheral ultrasound imaging system includes an ultrasound probe, an electronic apparatus capable of sending and receiving signals to and from the ultrasound probe, a hardware link connecting the electronic apparatus to a personal computer or computer network, and a software program for controlling the ultrasound probe, the electronic apparatus, and the hardware link. The ultrasound probe is connected to the electronic apparatus and the electronic apparatus is in turn connected to a personal computing device or a computer network.

Ultrasound therapy system and ablation results utilizing miniature imaging/therapy arrays

Array-based imaging and therapy systems have several advantages over single element approaches, and it was previously shown that the imaging and therapy functionality may be combined into dual-mode arrays. In this work, minimally invasive, miniature (2.2 mm /spl times/ 50 mm aperture, 3.3 mm diameter) dual-mode linear arrays have been developed into probes with high acoustic power output (100 W, and >120 W/cm/sup 2/ at the source), high transmit efficiency (>65% typical), and good imaging performance (3.4 MHz center frequency, 50% fractional bandwidth, >100 mm deep field of view). These therapy / imaging probes have been integrated into a flexible intense ultrasound surgery platform which also includes conventional diagnostic imaging probes. A system architecture has been developed which includes a 64-channel therapy driver with software selection of array aperture and phasing (1/16th wavelength), frequency (0.5-8 MHz), drive amplitude (5 W/channel, nominal), mechanical rotational steering (/spl plusmn/180 degrees), and temporal sequencing/switching of imaging, and therapy modes. The array-based imaging/therapy system has produced encouraging results in preclinical studies of bulk tissue ablation, imaging and treatment monitoring of liver in vitro and in vivo, examples of which are presented. The system can be applied to ablation of other soft tissue pathologies, e.g. kidney, heart, uterus, brain, GI, etc.

An ultrasonic ring transducer system for studies of scattering and imaging

A novel ultrasonic ring transducer and special control electronics have been developed for scattering and imaging studies. The transducer contains 2048 rectangular elements with a center frequency of 2.4 MHz and a −6‐dB bandwidth of 70%. At the center frequency, the element size is 0.29 wavelength ×40 wavelength and the spacing is 0.37 wavelength. A multiplexer provides access to any contiguous 128 elements for transmission and any contiguous 16 elements for simultaneous reception. The transmit electronics have independently programmable waveforms. The receive electronics have time‐varied gain functions independently programmable over the range 15–55 dB. Each receive channel includes a 20‐MHz, 12‐bit A/D converter. The electronics permit synthesis of arbitrary transmit and receive apertures. A novel ultrasonic wavefront design method has been implemented to determine element excitations using backpropagation of a user‐specified field pattern. Pulse‐echo compound images using constant f/1.0 transmit and receive apertures have been obtained for model scattering objects and an anthropomorphic breast phantom. Scattering measurements have been analyzed to obtain frequency‐ and angle‐dependent average differential scattering cross sections of random media. The system is a useful facility for measurements of ultrasonic scattering for characterization of tissue, development of adaptive beam‐formation techniques, and implementation of quantitative image reconstruction methods.

Feasibility of tissue effects produced by noninvasive high frequency intense therapy ultrasound via inertial cavitation

Considerable attention has been paid to ultrasound assisted delivery at relatively low frequency (20 kHz-3 MHz) and low acoustic intensity (<;3W/cm2). The purported mechanism of action is associated with cavitation increasing drug diffusion through the stratum corneum and epidermis. We show a feasibility of delivering clinically useful medicants through stratum corneum into skin utilizing Intense Therapeutic Ultrasound (ITU) high frequency (2.9-10 MHz), high intensity (>1,000 W/cm2) sound. Boiling histotripsy effects are also possible with ITU. Purported mechanism of action would include inertial cavitation and high pressure (>1MPa).

Therapy/imaging array‐based system and technology for intense ultrasound surgery

Minimally invasive, miniature (2.2‐ × 50‐mm aperture, 3.3‐mm diameter) dual‐mode linear arrays have been developed into low‐cost disposable probes with high acoustic power output (120 W/cm2 at the source), high transmit efficiency (>65% typical), and good imaging performance (50% fractional bandwidth, >100‐mm‐deep field of view). These therapy/imaging probes have been integrated into a flexible intense ultrasound surgery platform which also includes conventional diagnostic imaging probes. A system architecture has been developed which includes a 64‐channel therapy driver with software selection of array aperture and phasing (λ/16), frequency (0.5–8 MHz), drive amplitude (5 W/channel, nominal), rotational steering (±180 deg), and temporal sequencing/switching of imaging/therapy/monitoring modes. System software includes graphical and text‐based script mode control of therapeutic treatment. Real‐time monitoring of electric power per channel, temperature sensors, and thermal effects provide a range of feedba...