Anant K. Nigam

Bio: Anant K. Nigam is an academic researcher from New York Institute of Technology. The author has contributed to research in topics: Transducer & Ultrasonic sensor. The author has an hindex of 3, co-authored 3 publications receiving 182 citations.

Ultrasonic imaging system

Abstract: The invention is utilized in an apparatus for imaging sections of a body by transmitting ultrasonic energy into the body and determining the characteristics of the ultrasonic energy reflected therefrom. Such an apparatus typically includes a timer for generating timing signals, an energizing/receiving device alternately operative in response to the timing signals, and a display/record device, synchronized by the timing signals, for displaying and/or receiving image-representative electronic signals from the energizing/receiving device. In accordance with the invention there is provided a portable scanning module, suitable for being hand held, which comprises fluid-tight enclosure having a scanning window formed of a flexible material. A transducer is provided for converting energy from the energizing/receiving device to periodic ultrasonic energy and for converting reflected ultrasonic energy to electrical signals, the transducer having a plurality of defined segments. A variable delay device is coupled between the segments of the transducer and the energizing/receiving device, the variable delay means being responsive to the timing signals to effect electronic focusing of signals coupled therethrough. A focusing lens is coupled to the transducer. A fluid, such as water, is contained in the enclosure in the volume between the focusing lens and the scanning window. A reflective scanner device is disposed in the fluid between the lens and the window, and driving means, synchronized with the timing signals, is provided for moving the scanner device in periodic fashion.

Ultrasonic pulse-echo apparatus

Abstract: For use in ultrasonic pulse-echo apparatus including an ultrasonic wave transducer for transmitting an ultrasonic wave toward an object to be examined and for producing an electric signal corresponding to echo pulses reflected by the object, an improved signal processing circuit for compensating for attenuation effects caused by ultrasound absorption, diffraction, reflection and scattering. Compensation for these image-degrading effects assures simple, reliable and repeatable equipment performance, and contributes to reliable detection of very weak echoes.

Condenser‐microphone arrays in acoustical holography—a review

Abstract: The primary difficulties in producing acoustical holograms have been associated with the recording technique This paper presents some of the important recording techniques and highlights the desirability and advantages of using two‐dimensional arrays of linear, electroacoustic transducers for detecting holographic data in real time Recent developments of a class of such arrays, namely the condenser‐microphone arrays, are reviewed This is followed by an outline of the major considerations involved in the design of such arrays, the discussion of their characteristics, and their immediate and future prospects in acoustical holography

Thermal treatment methods and apparatus with focused energy application

Abstract: A collapsible ultrasonic reflector incorporates a gasfilled reflector balloon (50), a liquid-filled structural balloon (28) and an ultrasonic transducer (20) disposed within the structural balloon. Acoustic energy emitted by the transducer is reflected by a highly reflective interface between the balloons. In a cardiac ablation procedure, the ultrasonic energy is focused into an annular focal regions (44) to ablate cardiac tissue extending in an annular path along the wall. Devices for stabilizing the balloon structure and for facilitating collapse and withdrawal of the balloon structure are also disclosed.

Miniature ingestible capsule

Abstract: A miniature ingestible capsule has multiple therapeutic or diagnostic operations that can be performed. These functions are controlled by a combination of an outside control, a pose beacon and through information relayed from an imagining array and transmitter. These functions can be in a separate capsule without an imaging array or within the same capsule with an imaging array. Typically, there is one function performed in addition to imaging. These functions can include suction and spray capabilities, ultrasound sensor, lithotripsy, laser, heat, electrocautery, BICAP, biopsy forceps, a needle knife snare cautery (cold and hot with continuous or pulsed current for cutting and coagulation), with a basket, and fine needle aspiration with various wheels and fins and motors controlled externally and other tools to be used in humans. All of these tools can be attached to a retractable arm. Also, they can be used on an elevator device that lifts them, allowing for an extra 180° of movement.

Method and apparatus for selective cell destruction

Abstract: Method for destroying selected cells in a host without damage to non-selected cells comprises selecting a transmission path from an energy source (12) to the selected cells (30); determining one or more of the resonant frequencies of the selected cells (30); selecting as a destructive frequency one of the resonant frequencies at which the transmissibility of the selected cells (30) is higher than the transmissibility of the non-selected cells in the transmission path; and transmitting energy from the source (12) at the destructive frequency along the path with sufficient intensity to destroy the selected cells (30) without destroying the non-selected cells. Apparatus for practicing the method is also disclosed.

Cardiac ablation devices

Abstract: A cardiac ablation device treats atrial fibrillation by directing and focusing ultrasonic waves into a ring-like ablation region (A). The device desirably is steerable and can be moved between a normal disposition, in which the ablation region lies parallel to the wall of the heart for ablating a loop-like lesion, and a canted disposition, in which the ring-like focal region is tilted relative to the wall of the heart, to ablate only a short, substantially linear lesion. The ablation device desirably includes a balloon reflector structure (18, 1310) and an ultrasonic emitter assembly (23, 1326), and can be steered and positioned without reference to engagement between the device and the pulmonary vein or ostium. A contrast medium (C) can be injected through the ablation device to facilitate imaging, so that the device can be positioned based on observation of the images.

Ultrasound phased arrays

Abstract: Ultrasound transducers are disclosed which focus acoustic energy at various focal locations while minimizing focal spot degradation and the generation of unwanted on-axis or off-axis energy concentrations through using a generally constant f-number at the various focal locations.