THERAPEUTIC APPARATUS FOR ULTRASONIC TREATMENT

Abstract

A therapeutic apparatus for therapeutic ultrasonic treatment of a tissue region that contains a flowing liquid has at least one ultrasonic source and a control unit for activating the ultrasonic source in order to radiate ultrasonic pulses according to a pulse parameter set into the tissue region. The therapeutic apparatus has a measuring system configured to determine a flow velocity of the liquid and a focus control system configured to move a focus region of the ultrasonic pulse relative to the tissue region over a longitudinal portion. A movement direction of the focus region therein corresponds to a flow direction of the liquid and a movement velocity of the focus region corresponds to the flow velocity.

Claims

1. A therapeutic apparatus for therapeutic ultrasonic treatment of a tissue region having a flowing liquid, the therapeutic apparatus comprising: at least one ultrasonic source; at least one control unit configured to activate the at least one ultrasonic source according to a pulse parameter set in order to radiate ultrasonic pulses into the tissue region for the therapeutic ultrasonic treatment; a measuring system configured to determine a flow velocity of the flowing liquid; and a focus control system configured to move a focus region of the ultrasonic pulses relative to the tissue region over a longitudinal portion, wherein a movement direction of a movement of the focus region corresponds to a flow direction of the flowing liquid and a movement velocity of the movement of the focus region corresponds to the flow velocity.

2. The therapeutic apparatus of claim 1, wherein the measuring system comprises a Doppler sonography system.

3. The therapeutic apparatus of claim 1, wherein the measuring system is configured to determine, on a position-dependent basis, the flow velocity along the flow direction, and wherein the focus control system is configured to control the movement of the focus region so that the movement velocity corresponds to a maximum flow velocity of the flow velocity determined on the position-dependent basis.

4. The therapeutic apparatus of claim 3, wherein the focus control system is configured to control the movement of the focus region so that the focus region is moved along the flow direction via the longitudinal portion, wherein, in a first part of the longitudinal portion, the maximum flow velocity prevails, and wherein, in a second part of the longitudinal portion, a lower flow velocity prevails that is lower than the maximum flow velocity.

5. The therapeutic apparatus of claim 4, wherein the at least one control unit is configured to determine the pulse parameter set dependent upon the flow velocity such that, by way of the ultrasonic pulses radiated in, a destructive cavitation is caused in the first part of the longitudinal portion and no destructive cavitation is caused in the second part of the longitudinal portion.

6. The therapeutic apparatus of claim 4, wherein the at least one control unit is configured to determine the pulse parameter set dependent upon the flow velocity such that, by way of the ultrasonic pulses radiated in, a non-destructive cavitation is caused in the second part of the longitudinal portion.

7. The therapeutic apparatus of claim 6, wherein the measuring system is configured to determine a further flow velocity of cavitation bubbles that are created by the non-destructive cavitation in the second part of the longitudinal portion, and wherein the measuring system is further configured to determine the flow velocity of the flowing liquid based on the further flow velocity of the cavitation bubbles.

8. The therapeutic apparatus of claim 1, wherein the measuring system is configured to establish a change in the flow velocity, wherein the focus control system is configured to control the movement of the focus region so that the focus region so that the focus region is moved repeatedly along the longitudinal portion, and wherein the focus control system is configured to adapt the movement velocity of the movement of the focus region to the flow velocity according to the change in the flow velocity.

9. The therapeutic apparatus of claim 1, wherein the therapeutic apparatus comprises a histotripsy apparatus containing the at least one ultrasonic source.

10. The therapeutic apparatus of claim 1, wherein the focus control system is configured to control the movement of the focus region by way of electronic control of the at least one ultrasonic source, and wherein, during the movement of the focus region relative to the tissue region, a position and an orientation of the at least one ultrasonic source relative to the tissue region are unchanged.

11. The therapeutic apparatus of claim 1, wherein the at least one ultrasonic source comprises at least one phased-array transducer, and wherein the focus control system is configured to control the movement of the focus region by way of phase control of the at least one phased-array transducer.

12. The therapeutic apparatus of claim 11, wherein the at least one phased-array transducer comprises at least one annular phased-array transducer or at least one curved phased-array transducer.

13. The therapeutic apparatus of claim 1, wherein the measuring system is configured to determine the flow velocity of the flowing liquid.

14. A computer program product with commands which, when executed by a therapeutic apparatus, cause the therapeutic apparatus to: activate, by a control unit of the therapeutic apparatus, at least one ultrasonic source according to a pulse parameter set in order to radiate ultrasonic pulses for therapeutic ultrasonic treatment into a tissue region having a flowing liquid; determine a flow velocity of the flowing liquid by a measuring system of the therapeutic apparatus; and move, by a focus control system of the therapeutic apparatus, a focus region of the ultrasonic pulses relative to the tissue region over a longitudinal portion dependent upon the determined flow velocity, wherein a movement direction of a movement of the focus region corresponds to a flow direction of the flowing liquid and a movement velocity of the movement of the focus region corresponds to the flow velocity.

15. The computer program product of claim 14, wherein the commands, when executed by the therapeutic apparatus, cause the therapeutic apparatus to provide an ultrasonic treatment of a vessel constriction, and wherein the tissue region corresponds to a vessel having the vessel constriction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0067] FIG. 1 depicts a schematic representation of an exemplary embodiment in a therapeutic apparatus; and

[0068] FIG. 2 depicts a schematic representation of an example of a tissue region.

DETAILED DESCRIPTION

[0069] FIG. 1 shows schematically an exemplary embodiment of a therapeutic apparatus 1. Furthermore, a patient 3 and a tissue region of the patient 3, for example, a vessel 2 with a vessel wall 2a and a liquid 2b, in particular blood, flowing in the interior of the vessel is shown schematically. The vessel 2 is shown again schematically in FIG. 2.

[0070] The therapeutic apparatus 1 has one or more ultrasonic sources 4 and a control unit 6 configured to activate the ultrasonic sources 4 according to a pulse parameter set in order to radiate ultrasonic pulses into the vessel 2 for therapeutic ultrasonic treatment, so that, in particular, a focus region 8 of the ultrasonic pulses is also situated within the vessel 2. The extent of the focus region 8 may therein be larger than a vessel cross-section so that, for example, the focus region 8 overlaps with the vessel 2.

[0071] The therapeutic apparatus 1 has a measuring system 7, in particular a Doppler sonography system which may be controlled by the control unit 6. By this, the control unit 6 may determine a flow velocity of the liquid 2b in a position-dependent manner. If relevant, a separate measuring control unit (not shown) may also be provided for determining the flow velocity and/or for activating the measuring system 7.

[0072] The ultrasonic sources 4 are configured, for example, as phased-array transducers so that a focus control system 5 may control the position of the focus region 8 electronically, without the ultrasonic sources 4 themselves having to be moved. The focus control system 5 is configured to move the focus region 8 of the ultrasonic pulses relative to the vessel 2 parallel to the flow of the liquid 2b, wherein a movement velocity of the movement of the focus region 8 corresponds to the maximum flow velocity of the liquid 2b.

[0073] If the vessel 2 has, for example, a vessel constriction 9, the velocity of the liquid 2b in the region of the vessel constriction 9 is a maximum and in the adjacent regions 10a, 10b before and after the vessel constriction 9, it is lower.

[0074] The focus region 8 may thus be moved along the region 10a of the vessel constriction 9 and the region 10b with the maximum flow velocity. In the region of the vessel constriction 9, the relative velocity of the focus region 8 in relation to the liquid 2b is therefore equal to zero or approximately zero, whereas the relative velocity in the regions 10a, 10b is greater.

[0075] Thereby, destructive cavitation may be generated for histotripsy selectively and/or resonantly at the position of the vessel constriction 9. As a result of the bubble collapse in the liquid 2b in the region of the vessel constriction 9, sufficient energy is generated gradually to ablate the wall regions of the vessel walls of the vessel constriction 9. In the regions 10a, 10b cavitation bubbles that are possibly created move away from the focus region 8 so that an efficient multipulse excitation and collapsing of the cavitation bubbles does not take place.

[0076] Herein, the fact is made use of that the destructive cavitation is triggered, in the context of histotripsy, by a sequence of a plurality of strongly focused pulses, wherein one pulse alone causes no, or only slight, tissue damage. The excitation of the same tissue volume element or liquid volume element by the whole pulse sequence results in an efficient tissue destruction by histotripsy. Examples of use are, for instance, shock-scattering histotripsy or boiling histotripsy.

[0077] If the focus region is not moved at the flow velocity, an insufficient energy input for destructive cavitation may occur because a relative movement occurs between the liquid and the focus region. In one example, due to the movement adapted to the flow velocity of the focus region, the liquid and the focus region are static relative to one another, so that a destructive cavitation may be achieved.

[0078] Phase effects may therein lead, in particular, to an increased selectivity. If moved structures are resonantly excited with the correspondingly optimized ultrasonic phase position, the bubble formation is enhanced again here. Conversely, a non-phase-optimized excitation may be significantly less efficient where there is resonant energy input into the bubble cloud.

[0079] Making use of Doppler sonography, the flow velocity and the flow direction of the liquid 2b in the region of the vessel constriction 9 may be monitored and the movement of the focus region 8 as described may be dynamically adapted.

[0080] For example, if the vessel constriction 9 has changed its shape by way of the treatment, the change thereby caused to the flow velocity may thus be adjusted. The adaptation of the flow velocity to the pulse cycle is thus possible, for instance by gating at the maximum flow velocity within a pulse cycle and/or by way of continual adaptation of the pulse parameters.

[0081] In summary, a high degree of selectivity and safety in the treatment of tissue regions, particularly vessel stenoses, by histotripsy is enabled. Damage to healthy tissue may be prevented or reduced.

[0082] It is to be understood that the elements and features recited in the appended claims may be combined in different ways to produce new claims that likewise fall within the scope of the present disclosure. Thus, whereas the dependent claims appended below depend on only a single independent or dependent claim, it is to be understood that these dependent claims may, alternatively, be made to depend in the alternative from any preceding or following claim, whether independent or dependent, and that such new combinations are to be understood as forming a part of the present specification.

[0083] While the present disclosure has been described above by reference to various embodiments, it may be understood that many changes and modifications may be made to the described embodiments. It is therefore intended that the foregoing description be regarded as illustrative rather than limiting, and that it be understood that all equivalents and/or combinations of embodiments are intended to be included in this description.