Advanced Cardiovascular Systems, Inc.

Neocardia, LLC

Other

Omnitron International, Inc.

Georgia Tech Research Corporation

Guidant Coropration

Anthony J Bradshaw

Richard T Thornton

Wayne W Snyder

Kenneth M Bueche

Albert E Raizner

Michael H Hayman

J Eric Henckel

Michelle N Ledesma

Michael E Miller

Richard V Calfee

Steven Weinberg

Steven L Weinberg

John Eric Henckel

JoLynn R Thornton

Christopher J Ketchum

John R Hawkins

Raymond T Morrissy

Methods and apparatuses for positioning a radiation source in vivo relative to radio-opaque markers on a catheter that delineate a therapeutic treatment length so that a therapeutic dose of radiation is delivered along the therapeutic treatment length.

Methods and apparatuses for radiation treatment

A force sensing mechanism. The mechanism is provided with a beam having a stationary portion. A housing accommodates a portion of a device coupled to an afterloader and is coupled to the beam. A force sensor coupled to the beam monitors a force of the device. An afterloader system includes a processor and a cartridge to house the force sensing mechanism. In a method, the force sensing mechanism is provided to which a portion of a device coupled to an afterloader is coupled. A device force of the device is monitored.

Force sensing mechanism

A source wire having a radioactive source at its distal tip is used to treat a blood vessel within a patient's body by localized in vivo radiation to prevent stenosis of the blood vessel, including restenosis following percutaneous transluminal coronary angioplasty. The source wire is advanced to the target site along the intravascular system of the patient's body from a point external to the body. The source wire is preferably a solid lead of substantially uniform thickness along its entire length, composed of a superelastic nickel-titanium alloy (nitinol). Alternatively, the wire may be a cable composed of multiple strands of the alloy of substantially uniform thickness throughout the entire length of each strand. The alloy has desired characteristics of superelasticity for transitioning into and out of a stress-induced martensitic state as it is advanced through tortuous lumens for passage into the coronary arteries. The wire also is of a diameter suitable for passage into the coronary arteries, and the distal end of the wire may be tapered for ease of entry into narrowed portions. The targeted tissue is irradiated only briefly, with the radioactive source of the source wire positioned in the lumen of the coronary artery so as to deliver a substantially uniform dosage of radiation to the walls of the lumen.

Radioactive source wire, apparatus and treatment methods

A centering catheter with engagement knobs to provide improved perfusion in a vessel during intravascular radiation therapy. In one embodiment, a helical centering balloon catheter includes a helical centering balloon formed of helical lobes having a plurality of engagement knobs that outwardly protrude from the helical lobes. The helical lobes form a main spiral perfusion channel for perfusion of blood past the centering catheter. The engagement knobs compliantly engage the vessel walls and offset of the helical lobes such that auxiliary perfusion channels are formed around the engagement knobs between the helical lobes and the walls of the vessel to allow additional perfusion. In the event of a partial obstruction of the spiral channel or a single point failure, the auxiliary perfusion channels allow perfusion past the obstruction.

Centering catheter with improved perfusion

Apparatus and methods are disclosed for treating a stenosed region of a blood vessel such as a coronary artery by use of a single catheter for balloon angioplasty followed by delivery of a controlled inherently uniform dosage of radiation to the blood vessel wall to deter restenosis at the angioplasty site. In one embodiment, an angioplasty balloon catheter is adapted to have its balloon emptied after the angioplasty and then re-filled with radioactive fluid to re-engage the blood vessel wall at the angioplasty site. Another embodiment has a conventional angioplasty balloon surrounded by a radiotherapy treatment balloon that is separately inflatable with radioactive fluid. Partly filling the angioplasty balloon during the radiation treatment minimizes the volume of radioactive fluid necessary to achieve the desired dosage. In either embodiment, an outer containment balloon may be used to capture radioactive fluid that would otherwise escape if the treatment balloon were to rupture.

Combined angioplasty and intravascular radiotherapy method and apparatus

A source wire having a radioactive source at its distal tip is used to treat tissue at a target site within a patient's body by localized in vivo radiation. The source wire is advanced to the target site along the intravascular system of the patient's body from a point external to the body. The source wire is a solid lead of substantially uniform thickness along its entire length, composed of nickel-titanium alloy (nitinol). Alternatively, the wire may be a cable composed of multiple strands of the alloy of substantially uniform thickness throughout the entire length of each strand. The alloy has desired characteristics including flexibility, springiness, slipperiness, mechanical strength and shape memory retention, and the source wire is imparted with certain stressed and unstressed states that depend on flexation of the wire and a prescribed transition temperature. The wire has a diameter suitable for passage into the coronary arteries, and the distal end of the wire is tapered for ease of entry into narrowed portions. The tissue to be treated lies along a portion of the interior surface of a coronary artery which has been subjected to an angioplasty procedure to reduce blockage of the lumen and thereby improve blood flow. However, the angioplasty procedure may itself initiate restenosis. The targeted tissue is irradiated only briefly, with the radioactive source of the source wire centered as much as practicable in the lumen of the coronary artery, as by use a channeled centering balloon. This allows substantially uniform radiotherapy of the targeted tissue.

Method of treating a body vessel or duct with radiation from within the lumen

A radiation source for invasive medical treatment, such as intracoronary radiotherapy or other such intravascular radiotherapy, is described. The radiation source includes a thread extending longitudinally within a sleeve. The sleeve is a hollow circular cylinder, sealed at either end, made from a polyimide resin, and is configured such that it is sufficiently flexible enough to be used for intravascular radiotherapy. A plurality of laser-drilled holes are configured in an evenly spaced pattern along the sleeve, and promote uniform liquid evaporation from within the sleeve. The thread is comprised of twelve rayon filaments wound in a helical fashion, which extend longitudinally through the sleeve and are anchored in the seals at either end of the sleeve. A radioactive isotope is formed into a coating on surfaces within the sleeve. The coating is formed by introducing a drop of a liquid-borne radioactive isotope into contact with the sleeve such that capillary forces distribute the liquid throughout the sleeve, and evaporating the liquid to form a uniform plating of the isotope within the sleeve. The sleeve and thread include a coating of a surfactant to promote capillary action during the distribution of the liquid throughout the sleeve. During the formation of the sleeve, the sleeve and thread are wet and then dried, preshrinking them so as to avoid the sleeve's warping during later use.

Radiation source

Apparatus and methods are provided for relieving a stenosed region of a blood vessel such as a coronary artery using a single catheter that relieves the angioplasty by conventional means and then delivers an easily controllable inherently uniform dosage of radiation to the walls of a blood vessel for preventing restenosis after angioplasty. An embodiment of the apparatus comprises a catheter having an angioplasty balloon that is inflatable with a liquid containing a suspended radioactive material such as .sup.125 I or .sup.32 P. The balloon is surrounded by a membrane to capture the radioactive liquid in the event the balloon ruptures. The catheter is advanced through the patient until the balloon is disposed in the stenosed region of the blood vessel. The stenosed region is relieved using the angioplasty balloon, after which the angioplasty balloon is emptied and re-filled with the radioactive liquid, which expands the balloon to engage the walls of the blood vessel thereby providing an inherently uniform dosage of radiation to the blood vessel walls. Another embodiment of the apparatus comprises a catheter having an angioplasty balloon surrounded by a radiotherapy treatment balloon that is separately inflatable with a radioactive liquid. The stenosed region is relieved using the inner angioplasty balloon after which the radiotherapy treatment balloon is filled with the radioactive liquid. An additional containment balloon outside the radiotherapy treatment balloon may also be provided to prevent loss of radioactive liquid in the event the treatment balloon ruptures. The angioplasty balloon may be partly filled during the radiation treatment to minimize the volume of radioactive liquid necessary to achieve the desired dosage.

A method is disclosed for treating a blood vessel which has been subjected to interventional dilatation, to inhibit restenosis that would otherwise occur from cellular proliferation attributable to traumatic response at the site of the vessel interior wall where the dilatation was performed. The method includes introducing a radioactive source into the blood vessel so that the source is positioned adjacent to the site, and exposing targeted tissue of the vessel interior wall at the site to said radioactive source for a period of time sufficient to deliver a prescribed dose of radiation to the tissue. The rate at which the prescribed dose is delivered to the targeted tissue is adjusted to positively assure that the rate is held in a range with an upper limit of about 60 rads per second. Dose rate adjustment is controlled by selectively setting the distance between the source and the targeted tissue, or by appropriately selecting the length of the source according to the length of the site of targeted tissue along the vessel interior wall, and/or by appropriately attenuating the radiation emitted by the source to a desired reduced magnitude at the site of the targeted tissue, to positively assure that the dose rate delivered to the targeted tissue will not exceed 60 rads per second.

Device and method for controlling dose rate during intravascular

An afterloader for use in radiation oncology or intravascular radiotherapy comprises a wire storage mechanism for storing a radioactive-tipped sourcewire, a drive mechanism for advancing the sourcewire into a catheter or other channel implanted in a patient. A computer control system receives information from an encoder and a force sensor, which monitor the displacement of and the force exerted on the sourcewire, respectively. The displacement and force information are used to advance the wire at the fastest possible speed to the treatment site without exceeding a pre-programmed force profile designed to ensure the sourcewire does not puncture the catheter. The force profile is dynamic depending on the particular catheter being used, and catheter information may be inputted into the computer controller using a bar code or other information storage means in the catheter itself.

Afterloader with active force feedback

A treatment wire is provided for the delivery of a treatment to a site within the body that is composed of two stages. This treatment wire includes a single wire drive portion that is optimal for the proximal end of the treatment wire and engages any storage and/or drive mechanism that may be used in storing and/or deploying the treatment wire. The single drive wire is ground at its distal end to a smaller diameter and encased within a tube forming the second stage of the treatment wire. Because the drive wire terminates proximally to the tube, a cavity is formed that can retain the treating substance to be delivered to the patient. Shape-memory/superelastic material is preferably used for the construction of the treatment wire. When such material is used, the distal end of the treatment wire can be heat treated in order to render it more ductile and, therefore, more desirable for use in the tortuous passageways of the body.

Two-stage treatment wire

Apparatus and methods are provided for relieving a stenosed region of a blood vessel such as a coronary using a single catheter that relieves the angioplasty by conventional means and then delivers an easily controllable inherently uniform dosage of radiation to the walls of a blood vessel for preventing restenosis after angioplasty. An embodiment of the apparatus comprises a catheter having an angioplasty balloon that is inflatable with a liquid containing a suspended radioactive material such as .sup.125 I or .sup.32 P. The balloon is surrounded by a membrane to capture the radioactive liquid in the event the balloon ruptures. The catheter is advanced through the patient until the balloon is disposed in the stenosed region of the blood vessel. The stenosed region is relieved using the angioplasty balloon, after which the angioplasty balloon is emptied and re-filled with the radioactive liquid, which expands the balloon to engage the walls of the blood vessel thereby providing an inherently uniform dosage of radiation to the blood vessel walls. Another embodiment of the apparatus comprises a catheter having an angioplasty balloon surrounded by a radiotherapy treatment balloon that is separately inflatable with a radioactive liquid. The stenosed region is relieved using the inner angioplasty balloon after which the radiotherapy treatment balloon is filled with the radioactive liquid. An additional containment balloon outside the radiotherapy treatment balloon may also be provided to prevent loss of radioactive liquid in the event the treatment balloon ruptures. The angioplasty balloon may be partly filled during the radiation treatment to minimize the volume of radioactive liquid necessary to achieve the desired dosage.

A method and apparatus for intravascular radiotherapy for prevention of stenosis following angioplasty or other trauma to coronary arteries caused by smooth muscle cell hyperplasia in which a uniform dosage of radiation is delivered to the walls of the artery by positively positioning a radioactive source at the radial center of the artery being treated.

Method and apparatus for uniform radiation treatment of vascular lumens

Apparatus and methods are provided for delivering an easily controllable inherently uniform dosage of radiation to the walls of a blood vessel for preventing restenosis after angioplasty. The apparatus comprises a catheter having a balloon tip which is inflatable with a liquid containing a suspended radioactive material such as .sup.125 l or .sup.32 P. The catheter is advanced through the patient until this treatment balloon is disposed in the stenosed region of the blood vessel. The balloon is filled with the radioactive fluid which simultaneously expands and relieves the stenosis while irradiating the tissue, or if the stenosis has previously been relieved, the target tissue is irradiated by filling the treatment balloon with the radioactive fluid until the outer wall of the balloon engages, without substantially expanding, the inner wall of the blood vessel. An outer containment balloon is also provided to prevent loss of radioactive fluid in the event the treatment balloon ruptures and which may be used to perform the angioplasty prior to filling the treatment balloon with the radioactive fluid. The treatment balloon may be configured to minimize the volume of radioactive fluid necessary by providing an inner balloon filled with an inert material or by configuring the treatment balloon itself as a hollow cylinder with an annular chamber for receiving the radioactive fluid.

Growing community of inventors

Missouri City, TX, United States of America

Anthony J Bradshaw