83 results about "Tissue heating" patented technology

An electrosurgical medical device and technique for creating thermal welds in engaged tissue that provides very high compressive forces. In one exemplary embodiment, at least one jaw of the instrument defines a tissue engagement plane carrying first and second surface portions that comprise (i) an electrically conductive material and (ii) a positive temperature coefficient (PTC) material having a selected increased resistance that differs at each selected increased temperature over a targeted treatment range. One type of PTC material is a doped ceramic that can be engineered to exhibit a selected positively sloped temperature-resistance curve over about 37° C. to 100° C. The 70° C. to 100° C. range can bracket a targeted “thermal treatment range” at which tissue welded can be accomplished. The engineered resistance of the PTC matrix at the upper end of the temperature range will terminate current flow through the matrix. In one mode of operation, the engagement plane cause ohmic heating within tissue from Rf energy delivery tissue PTC matrix is heated to exceed the treatment range. Thereafter, energy density in the engaged tissue will be modulated as the conductivity of the second portion hovers within the targeted treatment range to thereby provide optical tissue heating for purposes of tissue welding.

An instrument and method are provided for sealing and joining or hemostatically dividing tissue, which is particularly suitable for laparoscopic and endoscopic surgery. The instrument makes use of the controlled application of a combination of heat and pressure to seal adjacent tissues, to join adjacent tissues, or to anastomose tissues, whereby tissue is heated for an optimal time and at an optimal temperature under optimal pressure to maximize tissue seal strength while minimizing collateral tissue damage. The instrument of the present invention is lightweight and therefore portable, and is particularly useful in field conditions where a source of external power may not be readily available.

Systems, apparatus, and methods for treating spinal tissue and other body structures in open and endoscopic spine surgery to relieve symptoms, such as neck or back pain. In particular, the present invention provides methods for the controlled heating of various tissues in or around the vertebral column, including various interspinous tissues, such that spinal ligaments and cartilage surrounding the vertebrae and the facet joints are shrunk or tightened to stabilize the vertebral column of a patient. Thermal energy is applied to the target tissue in a subablation mode of an electrosurgical system to cause shrinkage of the tissue, thereby stiffening the interspinous tissue and stabilizing the vertebral column. In an exemplary embodiment, a high frequency RF voltage can be applied between one or more active electrode(s) and one or more return electrode(s) to heat a target interspinous tissue to within a temperature range at which irreversible shrinkage of the tissue occurs.

An implantable battery powered leadless pacemaker or biostimulator is provided that may include any of a number of features. One feature of the biostimulator is that it safely operates under a wide range of MRI conditions. One feature of the biostimulator is that it has a total volume small enough to avoid excessive image artifacts during a MRI procedure. Another feature of the biostimulator is that it has reduced path lengths between electrodes to minimize tissue heating at the site of the biostimulator. Yet another feature of the biostimulator is that a current loop area within the biostimulator is small enough to reduce an induced current and voltage in the biostimulator during MRI procedures. Methods associated with use of the biostimulator are also covered.

A system and method for performing electrosurgical procedures are disclosed. The system includes an electrosurgical generator adapted to supply energy at an output level to tissue and to transmit an interrogatory signal to obtain initial tissue impedance to derive a starting impedance value. The electrosurgical generator includes a microprocessor adapted to generate a desired impedance trajectory as a function of either of the initial tissue impedance or the starting impedance value. The desired impedance trajectory includes a plurality of target impedance values. The electrosurgical generator is further adapted to drive tissue impedance along the desired impedance trajectory by adjusting the output level to match tissue impedance to a corresponding target impedance value. The system also includes an electrosurgical instrument including at least one active electrode adapted to apply electrosurgical energy to tissue.

A method and apparatus for fat destruction and body contouring. The method comprises pre-heating treated tissue and applying a high voltage pulse to destroy adipose tissue. The device includes an energy source for tissue heating and an HV pulse generator for applying voltage pulsed in the range of 200V to 5 kV.

The present invention provides, among other things, means to suppress AC current propagation along elongated medical devices incorporating long conductive structures. AC currents in the frequency range from approximately 10 MHz to 3 GHz can be substantially suppressed without altering the low and DC frequency response of the medical device.

A tissue cutting device includes a catheter with a window at its distal tip for admitting tissue into a catheter compartment. A cylindrical cartridge in the compartment has a cutting edge that supports an electrically conductive cutting element, e.g. a band or wire. The cutting element and adjacent tissue can be heated to a selected temperature by generating an electrical current through the cutting element. The catheter is maneuverable to position its distal end near the tissue to be cut. The catheter incorporates a dilatation balloon or other feature to urge the catheter against the tissue, so that at least part of the tissue may enter the compartment through the window. Then, the cartridge is manipulated from the catheter's proximal end to move the cutting edge across the window, cutting the tissue. According to alternative embodiments, the cartridge is either rotated or moved axially relative to the catheter and, in either event may be capable of closing the catheter window when the cut is complete. Further alternatives involve either placing an indifferent electrode on the patient and providing an RF signal via a single conductor to the cutting element for ohmic heating, or providing an RF (or a DC) current through the cutting element and two separate conductors for direct resistive heating of the cutting element.

Systems and methods are provided for modeling and for providing a graphical representation of tissue heating and electric field distributions for medical treatment devices that apply electrical treatment energy through one or a plurality of electrodes. In embodiments, methods comprise: providing one or more parameters of a treatment protocol for delivering one or more electrical pulses to tissue through a plurality of electrodes; modeling electric and heat distribution in the tissue based on the parameters; and displaying a graphical representation of the modeled electric and heat distribution. In another embodiment, a treatment planning module is adapted to generate an estimated target ablation zone based on a combination of one or more parameters for an irreversible electroporation protocol and one or more tissue-specific conductivity parameters.

A non-invasive apparatus and method for increasing saliva and tear production from the salivary and lacrimal glands with the application of high frequency low intensity ultrasound. An ultrasound transducer coated with connecting gel placed in contact with the facial tissues transmitting 1.5 MHz frequency ultrasound pressure waves into the tissues and into the glands. The time-averaged intensity of the ultrasound pressure waves is typically limited to approximately 30 milliwatts per square centimeter to avoid tissue heating.

Systems and methods apply ultrasound energy to achieve vasodilation and/or to increase tissue perfusion without causing substantial deep tissue heating.

Systems and methods are provided for modeling and for providing a graphical representation of tissue heating and electric field distributions for medical treatment devices that apply electrical treatment energy through one or a plurality of electrodes. In embodiments, methods comprise: providing one or more parameters of a treatment protocol for delivering one or more electrical pulses to tissue through a plurality of electrodes; modeling electric and heat distribution in the tissue based on the parameters; and displaying a graphical representation of the modeled electric and heat distribution. In another embodiment, a treatment planning module is adapted to generate an estimated target ablation zone based on a combination of one or more parameters for an irreversible electroporation protocol and one or more tissue-specific conductivity parameters.

In a method and an apparatus for magnetic resonance guided high intensity focused ultrasound (HIFU), precise localization of the focal point of the HIFU is determined by imaging an examination subject in parallel with GRE sequences that respectively include a positive monopolar gradient pulse and a negative monopolar gradient pulse, that respectively encode the acoustic radiation force (ARF)-induced phase shift that is induced by the simultaneous activation of HIFU during the sequences. A GRE phase image is reconstructed from each acquisition sequence, and a difference image is formed between the two GRE phase images, from which the HIFU focal point is determined. An average image is formed of the two GRE phase images from which PRFS temperature map is determined simultaneously to ARFI map. The use of parallel imaging and the use of partial Fourier reconstruction for reconstructing the GRE phase images allows the data to be acquired sufficiently rapidly so as to minimize the adverse effect of tissue heating that occurs with conventional longer-duration, and repetitious, techniques.

A thermotherapy catheter for heat treating the prostate gland includes an O-ring positioned within a chamber between an outer tube and an interior heat generation device guide tube. The O-ring supports a distal end portion of a probe guide tube at a desired acute angle so that a temperature probe can be advanced from the end of the probe guide tube into the prostate gland at a predetermined desired acute angle for calculating tissue heating and tissue necrosis information from temperature sensors located on a distal end of the temperature probe. The O-ring also separates a still liquid chamber from a circulatory flow path so that heated liquid surrounding the generation device is applied effectively to heat the prostate gland, while the circulating cooling fluid effectively removes heat from a feed cable which supplies energy to the heat generation device.

The invention discloses an ultrasonic method for measuring temperature change of biological tissue based on thermal expansion and gating algorithm. Aiming at the problem that temperature increment ofa target area cannot be effectively monitored in methods for treating diseases based on various current body tissue heating modes, a method for evaluating the temperature change of the biological tissue by using B-mode ultrasound RF signals is established. According to the method, methods such as focused ultrasound, radio frequency and microwave are used for locally heating the biological tissue,B-mode ultrasound is used for imaging the target area and collecting the RF signals of the target area, a target frame is selected based on B-mode ultrasound timing sequence images, time delay imagesthat ultrasound passes through the tissue are calculated, and accordingly temperature change images are obtained; according to images outside a heating area, the coefficient of a self-adaption filteris calculated, and the obtained temperature change images are subjected to noise suppression. According to the ultrasonic method, the error in the temperature increment range of 18 DEG C is smaller than or equal to 2 DEG C, the temperature increment monitoring technology of B-mode ultrasound is promoted to be applied to thermal therapy, and the safety and effectiveness of the thermal therapy can be remarkably improved.

The invention discloses a magnetic nanometer temperature measuring method based on effective relaxation time. The method comprises the following steps that magnetic nanometer particles are placed in an object area to be detected inside a nontransparent article; the magnetic nanometer particles in the object area to be detected are subjected to tissue heating with a radio frequency magnetic field, and meanwhile magnetizing response information of the magnetic nanometer particles under the excitation of the radio frequency magnetic field is obtained with a coil of a hollow structure; the amplitude value of any harmonic signal in magnetizing response signals of the magnetic nanometer particles is extracted; effective relaxation time serves as an intermediate variable, and the relation between the amplitude values of harmonic signals and the absolute temperature is established with the harmonic information to solve the absolute temperature. According to the method, a mathematical model between the magnetizing response harmonic amplitude value information of the magnetic nanometer particles and temperatures is established with the effective relaxation time, the temperature information of the article can be rapidly and accurately obtained, and especially the temperatures are measured while a radio frequency field is heated under the premise that no excitation magnetic field is added in magnetic nanometer thermal therapy.

A diathermy apparatus includes a cylindrical coil (24) defining an opening (42), a pair of capacitors of substantially similar capacitance (20 and 22), each capacitor connected to one end of the coil, an RF signal source (26), and a balun (28) connected between the RF signal source (26) and the pair of capacitors (20 and 22). The balun (28) is operative for converting an unbalanced signal received from the RF signal source (26) into a balanced signal supplied to coil (24) via the pair of capacitors (20 and 22). Desirably, the cylindrical coil is a conical cylindrical (or cone-shaped) spiral coil.