WO2013122984A1

WO2013122984A1 - Magnetic field apparatus for creating uniform magnetic field for vascular magnetic intervention

Info

Publication number: WO2013122984A1
Application number: PCT/US2013/025834
Authority: WO
Inventors: Robert J. Levy
Original assignee: The Childrens Hospital Of Philadelphia
Priority date: 2012-02-13
Filing date: 2013-02-13
Publication date: 2013-08-22

Abstract

A magnetic field apparatus for use in vascular magnetic intervention includes a moveable carrier and a pair of magnets mounted on the carrier. The magnets may be permanent magnets or electromagnets. A method for applying a magnetic field to a treatment site during vascular magnetic intervention may include the steps of moving a magnetic field apparatus into proximity to the treatment site, moving the pair of magnets on the moveable carrier into proximity to the treatment site, with one of the magnets positioned on a first side of the treatment site, and the other magnet positioned on a second side of the treatment site, the second side different from the first side, and applying a uniform magnetic field to the treatment site.

Description

MAGNETIC FIELD APPARATUS FOR CREATING UNIFORM MAGNETIC FIELD

FOR VASCULAR MAGNETIC INTERVENTION

RELATED APPLICATIONS

This application claims the benefit of priority of U.S. Application No. 61/598,019, filed February 13, 2012, the contents of which is incorporated by reference herein.

FIELD

This disclosure relates generally to the therapeutic treatment of an animal or human, and more specifically to an apparatus for creating a uniform magnetic field during therapeutic treatment of an animal or human, using magnetic targeting of therapeutic compounds.

BACKGROUND

Vascular magnetic intervention (VMI) is a procedure for delivering iron oxide- containing, magnetically responsive, biodegradable nanoparticles containing

therapeutic agents to permanently deployed superparamagnetic stents in vivo, or to temporary magnetic targeting devices (TMTDs). VMI involves at least three

components: (1) a magnetic nanoparticle (MNP) containing a therapeutic agent, (2) a magnetic targeting device that can be positioned at the site to be treated and serve as a target for the nanoparticles, and (3) a magnetic field apparatus.

The feasibility of VMI has been demonstrated for delivering drugs, gene vectors and cell therapy. Targeting of MNPs to permanent stents or TMTDs can be enhanced by application of a relatively uniform magnetic field. The following patents and published patent applications, which describe various aspects of magnetic targeting procedures, are incorporated herein by reference: U.S. Patent No. 7,846,201, U.S. Pub. No.

2009/0216320, U.S. Pub. No. 2009/0082611, U.S. Pub. No. 2010/0260780,

International Pub. No. WO 2004/093643, and International Pub. No. WO 2012/061193.

Magnetic targeting of MNPs can be performed by applying a uniform magnetic field in the vicinity of a treatment site, which may be a blood vessel or tissue area in an animal or human. The uniform magnetic field may be applied to the superficial femoral artery of a human, for example. The superficial femoral artery is the largest artery in the human leg, which is commonly affected by peripheral artery disease.

The magnetic field apparatus may consist of a pair of permanent magnets or a pair of electromagnets. The magnets must be properly positioned relative to the treatment site. For this to happen, the magnetic field apparatus must allow the relative positions of the magnets to be arranged and adjusted as necessary to generate the magnetic field at the precise location of the treatment site. The magnetic field apparatus must also provide a mechanism that allows easy placement and removal of the magnets to and from the vicinity of the treatment site. SUMMARY

Magnetic field apparatuses in accordance with the invention include apparatuses for properly positioning a pair of permanent magnets, or a pai r of electromagnets, relative to a treatment site. In one embodiment, a magnetic field apparatus includes a moveable carrier and at least one pair of magnets mounted on the carrier. The moveable carrier may feature a movable cart, such as a wheeled cart. The cart may feature a first track and a second track. A magnet may be positioned on the first track, and slidably displaceable on the first track. Another magnet may be positioned on the second track and slideably displaceable on the second track.

Alternatively, the moveable carrier may include a C-arm unit. The C-arm unit may include a first end and a second end opposite the first end, with one of the pair of magnets positioned at the first end, and the other of the pair of magnets positioned at the second end. The moveable carrier may also feature a bracket, rail or frame extending between the first and second ends of the C-arm. The magnets may be slidably mounted on the bracket, rail or frame.

In another embodiment, the moveable carrier may feature a cart, such as a wheeled cart, and an articulating arm or boom extending from the cart. The boom may include a free end, with the pair of magnets mounted on the free end of the boom.

In another embodiment, the moveable carrier may support a pair of magnets in a vertical arrangement, with one magnet configured to be placed underneath the patient, and the other magnet supported above the patient. The moveable carrier may include a first extension and a second extension vertically positioned above the first extension. One of the magnets may be mounted on the first extension and the other magnet may be mounted on the second extension. The second extension on the moveable carrier may include a support surface, such as a limb support, adapted to be positioned beneath a subject's limb to support the limb in a raised position above the operating table.

In another embodiment, the magnetic field apparatus may include at least one handle for manually lifting the moveable carrier and magnets, so that the entire apparatus can be placed on an operating table or removed from the operating table by manual lifting.

In another embodiment, the magnetic field apparatus may feature a cart, such as a wheeled cart, and at least one track on which the moveable carrier is slida ble. The moveable carrier may include at least one handle for sliding the moveable carrier along the track, from the cart to the operating table, and vice versa.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary and the following detailed description will be better understood in conjunction with the drawing figures, of which :

Figure 1 is a side view of a magnetic field apparatus in accordance with a first embodiment, with the apparatus shown in a first position before treatment of a patient;

Figure 2 is a side view of the magnetic field apparatus of Figure 1, with the apparatus shown in a second position during treatment of a patient;

Figure 3 is a top view of the magnetic field apparatus of Figure 1, with the apparatus shown in the first position before treatment of a patient;

Figure 4 is an end view of a pair of magnets associated with the magnetic field apparatus of Figure 1;

Figure 5 is a perspective view of a magnetic field apparatus in accordance with a second embodiment;

Figure 6 is a perspective view of a magnetic field apparatus in accordance with a third embodiment;

Figure 7 is a side view of a magnetic field apparatus in accordance with a fourth embodiment, showing the apparatus during treatment of a patient;

Figure 8 is an end view of a pair of magnets associated with the magnetic field apparatus of Figure 7;

Figure 9 is a side view of a magnetic field apparatus in accordance with a fifth embodiment;

Figure 10 is a top view of the magnetic field apparatus of Figure 9, showing the apparatus during treatment of a patient;

Figure 11 is an end view of the magnetic field apparatus of Figure 9, showing the apparatus during treatment of a patient;

Figure 12 is a top view of a magnetic field apparatus in accordance with a sixth embodiment, with the apparatus shown during treatment of a patient; and

Figure 13 is an end view of the magnetic field apparatus of Figure 12, with the apparatus shown during treatment of a patient.

DETAILED DESCRIPTION

Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention.

Apparatuses in accordance with the invention provide a mechanism for transporting a uniform magnetic field source to and from a location where a uniform magnetic field is to be applied . These apparatuses not only provide a mechanism for moving magnets to and from a treatment site, but also provide a mechanism for precisely positioning each magnet relative to the treatment site so that the uniform magnetic field is applied over the proper area. The apparatuses further provide a mechanism for keeping each magnet in a stable position as the magnetic field is being applied . In some embodiments, the magnets can be located at any point in three dimensional space relative to the treatment site.

Referring now to Figures 1-4, a magnetic field apparatus 100 for use in VMI is shown in accordance with a first embodiment. Apparatus 100 includes a moveable carrier 110 and a magnetic field source 120, Moveable carrier 110 includes a wheeled cart 112. A first track 114 and second track 116 extend from a top surface 111 of cart. Preferably, the first and second tracks 114, 116 are elevated above the floor surface at a height corresponding to, or slightly higher than, the height H_T of the operating table T on which the animal or human is positioned, as shown in Figure 1. The first and second tracks 114, 116 extend outwardly from the cart in a cantilevered arrangement, with a significant portion of their length extending laterally from the cart, with nothing beneath the tracks. In this arrangement, the cart 112 may be wheeled up to the edge of operating table T so that tracks 114, 116 extend over the operating table in close proximity to the treatment site. Figure 2 shows cart 112 wheeled up against table T with the tracks extending on two sides of a patient's leg . Tracks 114 and 116 have free ends 114a, 116a positioned on either side of the leg.

In some instances, there may be a need to use the magnetic field apparatus with a number of different operating tables having different heights. Magnetic field apparatuses in accordance with the invention may employ a height adjustment mechanism for this purpose. Height adjustment mechanisms in accordance with the invention are operable to adjust the position of the tracks so that they extend at the proper height above an operating table. Apparatus 100, for example, may include a vertical adjustment mechanism 117 connected to each track 114, 116. The vertical adjustment mechanisms 117 may be in the form of mechanical jacks or hydraulic lifts. Alternatively, vertical adjustment mechanisms 117 may be in the form of two vertical rails. Each track 114, 116 can be slidably or detachably connected to each rail. Each rail may be equipped with a clamp, pin or bolt that allows the track to be coupled to the rail at a desired height, and subsequently uncoupled from the rail to allow the track to be reconnected to the rail at a different height.

Magnetic field source 120 includes a pair of magnets 122, 124. One of the magnets 122 is slidably displaceable in the first track 114, and the other magnet 124 is slideably displaceable in the second track 116. Magnets 122 and 124 are slidable between a stowed position, in which the magnets are positioned above the cart (Figure 1), and a deployed position in which the magnets are positioned at free ends 114a, 116a of the tracks (Figure 2). In the deployed position, the magnets can be positioned on either side of a patient's leg to direct a uniform magnetic field through the superficial femoral artery.

Referring to Figure 5, a magnetic field apparatus 200 for use in VMI is shown in accordance with a second embodiment. Magnetic field apparatus 200 features a moveable carrier 210 in the form of a C-arm unit 212. C-arm unit 212 includes a C- arm 214 mounded on a wheeled cart 215. C-arm 214 has a first end 216 and a second end 218 opposite the first end . A first magnet 222 is positioned at the first end 216 and a second magnet 224 is positioned at the second end 218. C-arm 214 has a range of motion that allows the two magnets to be moved together in relative translation, such as movement up, down, left and right relative to cart 215. C-arm 214 also allows tilting of the two magnets with respect to a vertical axis X passing through cart 215. First and second ends 216, 218 of C-arm are spaced apart so as to provide a relatively large space or gap 228 between magnets 222, 224. Gap 228 is sized to allow the first and second ends of the C-arm to straddle a hospital bed, table or other structure supporting a patient.

Apparatuses in accordance with the invention may include one or more adjustment mechanisms that allow the spacing between the two magnets to be increased or decreased. In particular, the apparatus may include a mechanism that initially allows the magnets to be spread apart, providing plenty of clearance to allow the magnets to be positioned around an animal or human. Once positioned, the mechanism can be used to move the magnets closer together, and consequently, closer to the treatment site.

Figure 6 shows a magnetic field apparatus 300 in accordance with a third embodiment that features a mechanism for adjusting the spacing between magnets. Apparatus 300 includes a C-arm 314 with first and second ends 316, 318, and a bracket or rail 319 that extends between the first and second ends. A first magnet 322 is positioned at the first end 316, and a second magnet 324 is positioned at the second end 318. First and second magnets 322, 324 are slidably mounted on rail 319 to allow adjustment of the distance between the first and second magnets. Each magnet 322, 324 can be moved on rail 319 and locked in a fixed position using a clamp, pin, nut, bolt or other locking means.

Referring to Figures 7 and 8, a magnetic field apparatus 400 for use in VMI is shown in accordance with a fourth embodiment. Magnetic field apparatus 400 features a moveable carrier 410 in the form of a cart 412 and an articulating boom 414 extending from the cart. Boom 414 has a free end 416, and a pair of magnets 422, 424 mounted on the free end . Apparatus 400 may be desirable where the magnets need to be placed using an overhead approach, i .e. from above the operating table. For example, apparatus 400 may be beneficial when surgical instruments, trays, and/or other medical equipment are positioned on the operating table around the treatment site. The overhead position of the boom 414 allows the magnets to be lowered to the desired positions, while minimizing or eliminating the need to move the objects that are on the operating table around the treatment site.

Referring to Figures 9-11, a magnetic field apparatus 500 for use in VMI is shown in accordance with a fifth embodiment. Magnetic field apparatus 500 features a hand-held carrier 510 that can be manually lifted and placed on an operating table T. Carrier 510 has a first extension 512 and a second extension 514 vertically positioned above the first extension . A first magnet 522 is mounted on first extension 512 and a second magnet 524 is mounted on second extension 514. First extension 512 includes a limb support 526 configured to be positioned beneath the limb or other body part of an animal or human, to support the body part in a raised position above the table. Hand-held carriers in accordance with the invention include at least one handle or gripping means to allow the carrier to be easily lifted and placed onto the operating table. Carrier 510, for example, includes a pair loop handles 530 on opposite sides of the carrier.

Referring to Figures 12 and 13, a magnetic field apparatus 600 for use in VMI is shown in accordance with a sixth embodiment. Magnetic field apparatus 600 includes a carrier 610 and magnets 622, 624 that are similar in many respects to the carrier and magnets in apparatus 500. Apparatus 600 differs in that it provides a wheeled cart 640 as an additional means for transporting the magnets to and from an operating table. Cart 640 includes at least one track or extension 642 that allows the carrier 610 to be transferred between the cart and operating table. Carrier may be movable along track 642 via sliding.

While preferred embodiments of the invention have been shown and described herein, it will be understood that such embodiments are provided by way of example only. Numerous variations, combinations, changes and substitutions will occur to those skilled in the art without departing from the spirit of the invention. Accordingly, it is intended that the appended claims cover all such variations as fall within the spirit and scope of the invention.

Claims

CLAIMS What is Claimed :

1. A magnetic field apparatus for use in vascular magnetic intervention, the magnetic field apparatus comprising :

a moveable carrier; and

a pair of magnets mounted on the carrier.

2. The magnetic field apparatus of claim 1, wherein the moveable carrier comprises a cart having a first track and a second track.

3. The magnetic field apparatus of claim 2, wherein one of the pair of magnets is slidably displaceable in the first track, and the other of the pair of magnets is slideably displaceable in the second track.

4. The magnetic field apparatus of claim 1, wherein the moveable carrier comprises a C-arm unit.

5. The magnetic field apparatus of claim 4, wherein the C-arm unit comprises a C-arm having a first end and a second end opposite the first end, with one of the pair of magnets positioned at the first end and the other of the pair of magnets positioned at the second end.

6. The magnetic field apparatus of claim 5, wherein the moveable carrier comprises a frame between the first and second ends, and the pair of magnets are slidably mounted on the frame to adjust the spacing between the pair of magnets.

7. The magnetic field apparatus of claim 1, wherein the moveable carrier comprises a cart and an articulating boom extending from the cart, the articulating boom having a free end, the pair of magnets mounted on the free end of the

articulating boom.

8. The magnetic field apparatus of claim 1, wherein the moveable carrier comprises a first extension and a second extension vertically positioned above the first extension, ,with one of the pair of magnets mounted on the first extension and the other of the pair of magnets mounted on the second extension.

9. The magnetic field apparatus of claim 8, wherein the second extension on the moveable carrier comprises a limb support configured to be positioned beneath a subject's limb to support the limb in a raised position.

10. The magnetic field apparatus of claim 8, wherein the moveable carrier comprises at least one handle for manually lifting and positioning the moveable carrier.

11. The magnetic field apparatus of claim 8, further comprising a cart supporting the moveable carrier, the cart comprising at least one track on which the moveable carrier is slidable.

12. The magnetic field apparatus of claim 11, wherein the moveable carrier comprises at least one handle for manually lifting and positioning the moveable carrier.

13. A method for applying a uniform magnetic field to a treatment site during vascular magnetic intervention, the method comprising the steps of:

5 moving a magnetic field apparatus into proximity to the treatment site, the

magnetic field apparatus comprising :

a moveable carrier; and

a pair of magnets mounted on the carrier;

moving the pair of magnets on the moveable carrier into closer proximity to the lo treatment site, with one of the magnets positioned on a first side of the treatment site, and the other magnet positioned on a second side of the treatment site, the second side different from the first side; and

applying a uniform magnetic field to the treatment site.

14. The method of claim 13, wherein the step of moving the pair of magnets i s on the moveable carrier into closer proximity to the treatment site comprises the step of moving the magnets toward one another to adjust the spacing between the magnets.