Methods and apparatus for focused ultrasound application
First Claim
1. A method for determining exposure parameters for a high intensity focused ultrasound system used to noninvasively target a blood vessel in a patient with a high intensity focused ultrasound beam, the method comprising:
- providing the high intensity focused ultrasound system including at least one ultrasound transducer having a plurality of transducer elementsimaging the blood vessel to be treated with the high intensity focused ultrasound beam;
identifying tissue along an ultrasound energy path through which there will be a subsequent application of ultrasound energy between the blood vessel and the at least one ultrasound transducer;
estimating high intensity ultrasound energy intensities at the blood vessel and non-zero ultrasound energy intensities at the tissue for a subsequent application of high intensity focused ultrasound through the tissue to the blood vessel along the ultrasound energy path between the blood vessel and the at least one ultrasound transducer based at least in part on the relative position between the transducer(s) and the blood vessel and the relative position between the transducer(s) and the tissue along the ultrasound energy path between the blood vessel and the at least one ultrasound transducer; and
determining exposure parameters for the high intensity focused ultrasound beam that cause the estimated energy intensity delivered to the blood vessel to remain above a first level while the estimated energy intensity at the tissue along the ultrasound energy path between the blood vessel and the at least one ultrasound transducer remains below a second level, wherein the second level is less than the first level but greater than zero, wherein the exposure parameters include at least one of ultrasound intensity level, exposure interval, and scan geometry, and wherein the exposure parameters are determined to ensure that the second level will not result in irreversible damage to the tissue along the ultrasound energy path between the blood vessel and the at least one ultrasound transducer.
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Accused Products
Abstract
An ultrasonic applicator unit (2) is used diagnostically to locate a puncture wound (316) in an artery and then therapeutically to seal the puncture wound with high intensity focused ultrasound (HIFU). A control unit (6) coupled to the applicator unit includes a processor (74) that automates the procedure, controlling various parameters of the diagnostic and therapeutic modes, including the intensity and duration of the ultrasonic energy emitted by the applicator unit. A protective, sterile acoustic shell (4), which is intended to be used with a single patient and then discarded, is slipped over the applicator unit to protect against direct contact between the applicator unit and the patient and to maintain a sterile field at the site of the puncture. The apparatus and method are particularly applicable to sealing a puncture made when inserting a catheter into an artery or other vessel. Several different procedures are described for locating the puncture wound, including imaging the vessel in which the puncture is disposed and use of a locator rod to determine the disposition of the puncture along the longitudinal axis of the artery.
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Citations
24 Claims
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1. A method for determining exposure parameters for a high intensity focused ultrasound system used to noninvasively target a blood vessel in a patient with a high intensity focused ultrasound beam, the method comprising:
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providing the high intensity focused ultrasound system including at least one ultrasound transducer having a plurality of transducer elements imaging the blood vessel to be treated with the high intensity focused ultrasound beam; identifying tissue along an ultrasound energy path through which there will be a subsequent application of ultrasound energy between the blood vessel and the at least one ultrasound transducer; estimating high intensity ultrasound energy intensities at the blood vessel and non-zero ultrasound energy intensities at the tissue for a subsequent application of high intensity focused ultrasound through the tissue to the blood vessel along the ultrasound energy path between the blood vessel and the at least one ultrasound transducer based at least in part on the relative position between the transducer(s) and the blood vessel and the relative position between the transducer(s) and the tissue along the ultrasound energy path between the blood vessel and the at least one ultrasound transducer; and determining exposure parameters for the high intensity focused ultrasound beam that cause the estimated energy intensity delivered to the blood vessel to remain above a first level while the estimated energy intensity at the tissue along the ultrasound energy path between the blood vessel and the at least one ultrasound transducer remains below a second level, wherein the second level is less than the first level but greater than zero, wherein the exposure parameters include at least one of ultrasound intensity level, exposure interval, and scan geometry, and wherein the exposure parameters are determined to ensure that the second level will not result in irreversible damage to the tissue along the ultrasound energy path between the blood vessel and the at least one ultrasound transducer. - View Dependent Claims (2, 3, 4)
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5. A method for determining one or more operational parameters of a high intensity focused ultrasound system for a noninvasive therapeutic application of a high intensity focused ultrasound beam to a patient, the method comprising:
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providing the high intensity focused ultrasound system including at least one transducer element; imaging a blood vessel to be exposed with the high intensity focused ultrasound beam emitted from the high intensity focused ultrasound system; estimating an acoustic path length between the transducer element(s) and the blood vessel; estimating an acoustic attenuation value of the high intensity focused ultrasound beam propagated from a position external to the patient based at least in part on the acoustic path length and a look up table of attenuation values; and determining one or more operational parameters of the high intensity focused ultrasound system based at least in part on the acoustic attenuation value, wherein the parameters ensure that a dose of high intensity therapeutic energy is delivered from the high intensity focused ultrasound system to the blood vessel while assuring that interpath tissue is not exposed to an energy intensity that will result in tissue damage, wherein the operational parameters include at least one of ultrasound intensity level, exposure interval, and scan geometry. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for determining one or more operational parameters of a high intensity focused ultrasound system for a noninvasive therapeutic application of a high intensity focused ultrasound beam to a vascular target, the method comprising:
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providing the high intensity focused ultrasound system including at least one transducer element; utilizing imaging to identify the vascular target to be exposed with the high intensity focused ultrasound beam emitted from at least one of the transducer element(s); estimating an acoustic path length between at least one of the transducer element(s) and the vascular target; estimating an acoustic attenuation value of the high intensity focused ultrasound beam propagated from a position external to the patient based at least in part on the acoustic path length and a look up table of attenuation values; and determining one or more operational parameters of the high intensity focused ultrasound system based at least in part on the acoustic attenuation value, wherein the parameters ensure that a dose of high intensity therapeutic energy is delivered from the high intensity focused ultrasound system to the vascular target while assuring that interpath tissue is not exposed to an energy intensity that will result in tissue damage, wherein the operational parameters include at least one of ultrasound intensity level, exposure interval, and scan geometry. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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Specification