摘要:
A method of selecting laser parameters for performing laser-assisted myocardial revascularization to avoid inducing undesired cardiac arrhythmia without synchronization of delivery of laser energy and the patient's cardiac cycle, the method comprising the steps of minimizing the power level of laser energy used, thereby decreasing the overall trauma to the heart, selecting a pulse frequency as great as possible while avoiding adverse summation effects, selecting a pulse width as wide as possible to prevent excessively high peak powers per pulse and not so wide as to cause undesired thermal damage, selecting an energy flux rate, shaping the front end of each pulse of laser energy to provide efficient, non-explosive TMR channeling, and correcting the selected power level, pulse width, pulse frequency and energy flux rate for mechanical events, including method of access to the heart, position of selected portions of myocardium in the heart, temporal duration of the procedure, natural movement of the heart, specific heart geometry, pre-existing heart arrhythmia and other factors causing a predisposition to heart arrhythmia. A method for performing laser-assisted transmyocardial revascularization (TMR) and percutaneous transluminal myocardial revascularization (PTMR) using such laser energy with parameters selected to avoid inducing undesired cardiac arrhythmia, the method comprising the steps of generating laser energy having a predetermined non-square wave shape, a predetermined wavelength, a predetermined energy flux and a predetermined power level, and delivering the laser energy in a plurality of pulses, the plurality of pulses having a predetermined pulse frequency and a predetermined pulse width, to selected portions of myocardium to form TMR and PTMR channels without synchronizing delivery of the laser beam with the cardiac cycle.
摘要:
A preionization assembly is adapted for use with a laser including a laser vessel, a high voltage electrode and a ground electrode defining a discharge region extending longitudinally within the vessel. A plurality of pin assemblies are arranged in at least one line which extends longitudinally through the vessel along the discharge region. These pin assemblies are generally equally spaced along the line, each including an anode pin and a cathode pin oriented relative to each other so that a spark passing therebetween arcs in a direction which is longitudinal of the vessel along the discharge region. The pin assemblies may be oriented in two parallel lines disposed in equally spaced relationship to the discharge region.
摘要:
In an ultraviolet polarizing device, a first piece of glass having a mating surface, a second piece of glass having a mating surface for mating with the mating surface of the first piece, a multilayer optical thin film coating disposed between the mating surface of the first and second pieces of glass, said mating surfaces and said thin film coating forming a physical bond therebetween without the use of a cement to thereby permit the polarizing device to be capable of withstanding high power laser energy.
摘要:
A dental video camera includes a housing which has an elongated cavity with a distal end and a proximal end, an adjustably focusing lens, a CCD camera system which is disposed within the elongated cavity of the housing, a fixed focusing lens system and an electrically adjustable iris. The adjustably focusing lens provides a focusing adjustment between a near field o:f focus and a far field of focus. The CCD camera system is optically coupled to the adjustably focusing lens and and is disposed in the elongated cavity of the housing adjacent to the distal end thereof. The electrically adjustable iris is optically coupled to the adjustably focusing lens and CCD camera system. The adjustable iris is adjusted between a nearly closed opening and a wide open opening in response to the focusing adjustment between the near field of focus and the far field of focus.
摘要:
A dental video camera includes a housing which has an elongated cavity with a distal end and a proximal end, an adjustably focusing lens and CCD camera system which is disposed within the elongated cavity of the housing, a fixed focusing lens system and an adjustable iris. The adjustably focusing lens and CCD camera system provides a focusing adjustment between a near field of focus and a far field of focus. The fixed focusing lens system is optically coupled to the adjustably focusing lens and CCD camera system and is disposed in the elongated cavity of the housing adjacent to the distal end thereof. The adjustable iris is optically and mechanically coupled to the adjustably focusing lens and CCD camera system. The adjustable iris is adjusted between a nearly closed opening and a wide open opening in response to the focusing adjustment between the near field of focus and the far field of focus.
摘要:
A laser head comprising a tube having a wall with the configuration of a hollow cylinder. A first ring flange extends radially generally outwardly of the tube wall at one end and is connected to the tube by a single continuous weld. A second plate flange is disposed at the same end and extends generally axially of the first flange. The first flange is coupled to the second flange and sandwiches a metal gasket therebetween to form a pressure seal. An electrode assembly is mounted to the second plate flange and at least one high voltage discharge feed extends through the wall of the tube to energize the electrode assembly. The tube is formed of a homogeneous metal that is free of any surface plating and is less reactive with Halogen gas than pure aluminum. In an associated method, the interior surface of the tube is polished to reduce the surface area and inhibit the entrapment of water vapor.
摘要:
Apparatus for optically controlling the output energy of a pulsed laser source comprising a laser producing a plurality of laser pulses in a laser beam. An optical attenuator is disposed in the laser beam to attenuate the energy in the laser beam to provide an attenuated laser beam, and a pick-off is provided for sensing the energy in the attenuated laser beam. A controller is coupled to the pick-off for controlling the optical attenuator to vary the energy in the attenuated laser beam to thereby vary the output fluence from the apparatus.