METHOD, DEVICE, AND METHOD FOR USING OF A DEVICE TO COAGULATE VARICOSE VEINS WITH HIGH-INTENSITY FOCUSED ULTRASOUND

Abstract

The invention discloses a method and a device to treat vessels. In particular, the invention is directed at a method to occlude varicose veins while avoiding the formation of bubble clouds in the tissue surrounding the vessel and/or their interaction with the ultrasound beam. The invention is further directed at a device adapted to perform the method.

Claims

1-22. (canceled)

23. A method for treatment of a hollow target by a HIFU beam having a focal spot wherein the focal spot is positioned at a position deeper than or tangent to a target depth representing the target, such as to avoid or limit the creation of bubbles in tissue located between a treatment head and a target during the emission of a pulse.

24. The method according to claim 23, wherein the target depth is the depth of the superficial part of the target wall.

25. The method according to claim 23, wherein the target depth is the depth of the deep part of the target wall.

26. The method according to claim 23, wherein the distance between the focal spot and the target depth is increased by a safety margin.

27. The method according to claim 23, wherein the target depth is determined for each treatment site based on an automatic segmentation algorithm.

28. The method according claim 23, wherein a marker representing a location related to the focal spot is overlaid on a monitoring image and the position of the focal spot is adjusted with respect to the target before each pulse.

29. The method according to claim 23, wherein the focal spot is placed such that the tissue located deeper than the target is damaged by the pulse, and the tissue located above the target is damaged less than the tissue above the target.

30. A method, comprising the steps of monitoring if a bubble cloud which may interact with the HIFU beam in the soft tissue is located above the target; and if such a bubble cloud is detected, modifying the location of the focal spot of a HIFU pulse

31. The method according to claim 34, wherein the modification occurs based on manual detection of the bubble cloud.

32. The method according to claim 34, wherein the modification occurs based on automatic detection of the bubble cloud.

33. The method according to claim 34, wherein the modification is triggered by the user.

34. The method according to claim 34, wherein the location of the pulse is modified by moving the beam about orthogonally to the main ultrasound propagation axis so that the HIFU beam is tangent to the bubble cloud.

35. The method according to claim 34, wherein the location of the pulse is modified by moving the beam about orthogonally to the main ultrasound propagation axis by a distance such that the HIFU beam and the bubble cloud are separated by a safety margin.

36. The method according to claim 34, wherein a 3D location of the bubble clouds is gathered by rotating a 2D imaging mean.

37. An ultrasound treatment device, the device comprising: a probe head having an ultrasound transducer for delivering treatment ultrasound waves focused onto a target within an object; an imaging device for imaging of the object comprising a display; a controller unit operatively connected to the ultrasound transducer for controlling the emission of HIFU pulses; and a memory, wherein at least one of a location related to the focal spot and a range along the ultrasound propagation axis where the target should be can be stored in the memory, wherein the display is adapted to overlay at least one marker on a monitoring image, wherein the marker represents at least one of the location related to the focal spot and the range along the ultrasound propagation axis where the target should be.

38. The device according to claim 37, wherein the controller unit is operatively connected to at least the actuator and the compression unit, wherein the device is adapted to: allow for a manual positioning of the focal spot of the treatment transducer in the vicinity of the target, and allow the user for indicating the position of the target or the desired position of the focal spot, or a range of acceptable positions, and automatically adapt the position of the focal spot based on an image tracking algorithm using the controller unit to set the focal spot, pilot the actuator, and/or the compression unit.

39. The device according to claim 37, wherein the focal spot is movable with a multielement transducer.

40. A method for using a device according to claim 37, comprising the steps of at least one of: manually placing the treatment transducer, so the focal spot is in the vicinity of the target and the target is within the field of view of the monitor; outlining the target or the desired position of the focal spot or an acceptable range of positions; and letting the device refining the parameters of the compression unit and moving the transducer to adequately place the focal spot.

41. A method of using an ultrasound treatment device, the device comprising: a hand-held probe head comprising an ultrasound transducer for delivering treatment ultrasound waves focused onto a target within an object and an imaging device for imaging of the object, and a controller unit operatively connected at least to the probe head and to a compression unit a compression unit for applying a compression force to the object, comprising a membrane (64) mounted onto the probe head filled with a fluid which is circulated by a pumping system (63), the controlling unit being adapted to control the pumping system (63) and the compression force by switching between at least two operating modes, wherein: in a first operating mode (R1) of the controller unit, moving the transducer orthogonally to the skin or along the main ultrasound propagation axis by a given distance thereby inducing a displacement of the focal spot by about the same distance and along the same direction within the anatomy in a second operating mode (R2) of the controller unit, moving the transducer orthogonally to the skin or along the main ultrasound propagation induces a compression of the target but no significant change of depth of the focal spot under the skin. the method including controlling the compression force and the pumping system (63) such that positioning the focal spot is performed in the mode R1 and adjusting the compression of the target is performed in the mode R2.

42. The method of using an ultrasound treatment device according to claim 41, further comprising a feedback loop, wherein the steps of positioning the focal spot and of adjusting the target compression are alternately repeated.

Description

[0097] In the following the invention is described in detail by reference to the following figures:

[0098] FIG. 1 schematically shows the effect of a bubble cloud interacting with the ultrasound beam.

[0099] FIG. 2 schematically illustrates a working principle of a method according to the invention in which the interaction between the bubble cloud and the ultrasound beam is avoided.

[0100] FIG. 3 schematically illustrates the location of the focal spot with different safety margins.

[0101] FIG. 4 schematically illustrates a working principle of the method according to the invention in which the interaction between the bubble cloud and the ultrasound beam is avoided from the top.

[0102] FIG. 5 shows a schematic depiction of a ultrasonic device according to the invention.

[0103] FIG. 6 shows schematically an orientation of a focus point with respect to a target and a treatment head.

[0104] FIG. 1 shows the working principle of the method according to the invention and illustrates the object of the invention. A HIFU treatment is delivered to a target comprising a wall 3 and a lumen 4. In order to avoid the formation of a bubble cloud in an area 2 between the target 3,4 and a treatment head, the focus 32 of the HIFU beam is placed lower than a target level 31 in the direction of the ultrasound propagation. In this example, the target level is chosen to be the inner surface boundary of the target wall 3. However, it is also possible to use the outer surface level or the center of the target wall 3. The lower focus 32 allows for the treatment without the formation of a new bubble cloud.

[0105] However, it is possible that a previous pulse 5 has generated a bubble cloud in the area 2 which interacts with the ultrasound beam 1. This interaction creates a zone where heating is increased 6 and a zone which is shadowed 7.

[0106] FIG. 2 shows schematically a preferred embodiment of a method according to the invention. During the treatment of a target comprising a wall 3 and a lumen 4, the HIFU beam 1 is located such that no bubble cloud is expected to be created in the tissue above the target. However, a bubble cloud has formed in an area 2 in a previous HIFU emission step (not shown) and is detected. Because the present bubble cloud in the area 2 may interact with the HIFU beam 1, the location of the HIFU beam is modified by laterally moving by an appropriate distance 8 to avoid the interaction.

[0107] FIG. 3 shows how in the context of a treatment of a target comprising a wall 3 and a lumen 4, the focal spot 9 is tangent to the more superficial border of the target (FIG. 3a), to the center of the target (FIG. 3c), or the deeper border of the target (FIG. 3e). Additional safety margins can be taken (FIGS. 3b, 3d, and 3f). Although not explicitly shown in the figure, the person skilled in the art will recognize that other locations for the focal spot, in particular locations in between the illustrated cases, are possible. For example, the focal spot may be tangent to the outer surface level of the upper wall, or the inner surface level of the upper wall. In all cases the soft tissue located deeper than the target is damaged. As a general rule, the deeper with respect to a target level the focus spot 9 is located, the less probable the formation of a bubble cloud in the tissue above the target wall 3 is. However, with increasing depth, the treatment effect on the target wall 3 becomes smaller. Thus, the focal spot should be located as deep as necessary to avoid the formation of bubble clouds, but as close to the target level as possible.

[0108] FIG. 4 illustrates a treatment in a plane perpendicular to the propagation axis of the HIFU beam. In the context of a treatment of a target comprising a wall 3 and a lumen 4, the previous pulses 10a, 10b, and 10c have generated bubble clouds 11 which extend into the soft tissue located above the target. When positioned at the planned site 12, the imaging probe is rotated to assess the bubble clouds 11 generated by the previous pulses 10a-10c. Since the bubble cloud 11 would interact with the HIFU beam (not shown), the site is move to another position 13.

[0109] FIG. 5 shows schematically a device 50 according to the invention to treat a patient with HIFU. The device 50 comprises a probe head 51 with a treatment transducer 55. The transducer is adapted to deliver ultrasound waves focused onto a target 54 in an object 53. In the present embodiment, the treatment head 51 further comprises an imaging device 56. The treatment head further comprises a compression unit 52, here in the form of a membrane 64 that is mounted onto the probe head 51 and forms a cavity for receiving a fluid. The fluid in the cavity is circulated by a pumping system 63. The device further comprises an actuator 60 that is connected to the probe head 51 by an arm 57 and that is adapted to move the treatment head 51 along the main ultrasound propagation axis 58 and orthogonally to the patient skin 59. The device also comprises a controller unit 61 that is operatively connected to the transducer 55, the compression unit 52 and the actuator 60, in the present example by means of a cable 62.

[0110] FIG. 6 shows schematically a treatment head 51 as shown in FIG. 5 with a balloon 52 placed on a patient's skin 100 such as to treat a target 103. The center of the focal point 101 is placed at a position deeper than the target. For illustration, an axis 102 is shown that extends from the treatment head 51 through the target 103. The center of the focal spot 101 is further away from the treatment head 51 than the target, i.e. a distance between the treatment head 51 and the center of the focal spot 101 is larger than a distance between the target and the treatment head 51. Accordingly, the center of the focal spot 101 is not placed between the target 103 and the treatment head.