System and method for performing an electrosurgical procedure using an ablation device with an integrated imaging device

An ablation device includes an antenna assembly having a radiating portion configured to deliver energy from a power source to tissue. The radiating portion has an outer conductor and an inner conductor. The inner conductor is disposed within the outer conductor. The device also includes an imaging device operably coupled to the radiating portion. The imaging device is configured to generate imaging data corresponding to tissue proximate the radiating portion of the antenna assembly.

BACKGROUND

1. Technical Field

The present disclosure relates to energy-based apparatuses, systems and methods. More particularly, the present disclosure is directed to a system and method for performing an electrosurgical procedure using an ablation system including an integrated imaging device.

2. Background of Related Art

In the treatment of diseases such as cancer, certain types of cancer cells have been found to denature at elevated temperatures (which are slightly lower than temperatures normally injurious to healthy cells.) These types of treatments, known generally as hyperthermia therapy, typically utilize electromagnetic radiation to heat diseased cells to temperatures above 41° C., while maintaining adjacent healthy cells at lower temperatures where irreversible cell destruction will not occur. Other procedures utilizing electromagnetic radiation to heat tissue also include ablation and coagulation of the tissue. Such microwave ablation procedures, e.g., such as those performed for menorrhagia, are typically done to ablate and coagulate the targeted tissue to denature or kill the tissue. Many procedures and types of devices utilizing electromagnetic radiation therapy are known in the art. Such microwave therapy is typically used in the treatment of tissue and organs such as the prostate, heart, liver, lung, kidney, and breast.

One non-invasive procedure generally involves the treatment of tissue (e.g., a tumor) underlying the skin via the use of microwave energy. The microwave energy is able to non-invasively penetrate the skin to reach the underlying tissue. However, this non-invasive procedure may result in the unwanted heating of healthy tissue. Thus, the non-invasive use of microwave energy requires a great deal of control.

Presently, there are several types of microwave probes in use, e.g., monopole, dipole, and helical. One type is a monopole antenna probe, which consists of a single, elongated microwave conductor exposed at the end of the probe. The probe is typically surrounded by a dielectric sleeve. The second type of microwave probe commonly used is a dipole antenna, which consists of a coaxial construction having an inner conductor and an outer conductor with a dielectric junction separating a portion of the inner conductor. The inner conductor may be coupled to a portion corresponding to a first dipole radiating portion, and a portion of the outer conductor may be coupled to a second dipole radiating portion. The dipole radiating portions may be configured such that one radiating portion is located proximally of the dielectric junction, and the other portion is located distally of the dielectric junction. In the monopole and dipole antenna probe, microwave energy generally radiates perpendicularly from the axis of the conductor.

The typical microwave antenna has a long, thin inner conductor that extends along the axis of the probe and is surrounded by a dielectric material and is further surrounded by an outer conductor around the dielectric material such that the outer conductor also extends along the axis of the probe. In another variation of the probe that provides for effective outward radiation of energy or heating, a portion or portions of the outer conductor can be selectively removed. This type of construction is typically referred to as a “leaky waveguide” or “leaky coaxial” antenna. Another variation on the microwave probe involves having the tip formed in a uniform spiral pattern, such as a helix, to provide the necessary configuration for effective radiation. This variation can be used to direct energy in a particular direction, e.g., perpendicular to the axis, in a forward direction (i.e., towards the distal end of the antenna), or combinations thereof.

Invasive procedures and devices have been developed in which a microwave antenna probe may be either inserted directly into a point of treatment via a normal body orifice or percutaneously inserted. Such invasive procedures and devices potentially provide better temperature control of the tissue being treated. Because of the small difference between the temperature required for denaturing malignant cells and the temperature injurious to healthy cells, a known heating pattern and predictable temperature control is important so that heating is confined to the tissue to be treated. For instance, hyperthermia treatment at the threshold temperature of about 41.5° C. generally has little effect on most malignant growth of cells. However, at slightly elevated temperatures above the approximate range of 43° C. to 45° C., thermal damage to most types of normal cells is routinely observed. Accordingly, great care must be taken not to exceed these temperatures in healthy tissue.

In the case of tissue ablation, a high radio frequency electrical current in the range of about 500 mHz to about 10 gHz is applied to a targeted tissue site to create an ablation volume, which may have a particular size and shape. The targeted tissue site is observed prior to the application of energy thereto to ensure accurate placement of the ablation device (e.g., microwave antenna) relative to the targeted tissue site. Typically, observation is facilitated through scanned data obtained through use of imaging devices such as CT, MRI, PET, or other tomographic or X-ray devices. However, images obtained using such scanning techniques before, during, or after an electrosurgical procedure, such as tissue ablation, are obtained from outside the patient and, therefore, are often lacking in quality due to distortions and the limitations of two-dimensional imaging.

SUMMARY

According to an embodiment of the present disclosure, an ablation device includes an antenna assembly having a radiating portion configured to deliver energy from a power source to tissue of a patient. The radiating portion has an outer conductor and an inner conductor. The inner conductor is disposed within the outer conductor. The device also includes an imaging device operably coupled to the inner conductor. The imaging device is configured to generate imaging data corresponding to tissue proximate the radiating portion of the antenna assembly.

According to another embodiment of the present disclosure, a microwave ablation system includes an antenna assembly configured to deliver energy from a power source to tissue of a patient and an introducer having a distal end configured to penetrate tissue. The introducer has a lumen disposed coaxially therein at least partially along its length. The lumen is configured to receive the antenna assembly therein. The system also includes an imaging device disposed on the introducer configured to provide imaging data to a processing unit corresponding to tissue proximate the introducer. The processing unit is configured to generate an image based on the imaging data.

According to another embodiment of the present disclosure, a method for performing an electrosurgical procedure includes the steps of positioning an ablation device including an imaging device proximate a desired tissue site of a patient and imaging the desired tissue site to generate corresponding imaging data. The method also includes the steps of generating a display of the desired tissue site based on the imaging data and re-positioning the ablation device proximate the desired tissue site based on the display. The method also includes the step of supplying energy from an energy source to the ablation device for application to the desired tissue site.

DETAILED DESCRIPTION

Particular embodiments of the present disclosure are described hereinbelow with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. In the discussion that follows, the term “proximal” will refer to the portion of a structure that is closer to a user, while the term “distal” will refer to the portion of the structure that is farther from the user.

Generally, the present disclosure relates to the use of an ablation device having an integrated imaging device, such as an ultrasound transducer adapted to generate image data by generating sound waves within the ultrasound frequency range toward a desired imaging site and subsequently receiving echoing of such sound waves from the desired imaging site. The ability to radially visualize target tissue before, during, and/or after an ablation procedure in three dimensions allows a user to accurately place the ablation device within the target tissue and, further, to monitor ablation progress.

An ablation device (e.g., a microwave ablation device) in accordance with the present disclosure is referred to in the figures as reference numeral10. While a microwave ablation device is described herein, it is contemplated that the present disclosure may also be used in connection with other types of ablation devices and other instruments, such as introducers. Such ablation devices may include an antenna and/or an electrode.

Referring initially toFIG. 1, ablation device10includes an antenna12and a handle portion13. Antenna12includes a shaft or feedline14having an inner conductor16and an outer conductor20, which defines a longitudinal axis X-X. Outer conductor20may be, for example, an introducing structure (e.g., needle) configured to pierce and/or penetrate tissue. A power transmission cord21is shown and connects ablation device10to a suitable electrosurgical generator22(seeFIGS. 2A and 2B). Additionally, an actuation element7is illustrated inFIG. 1in accordance with various embodiments of the present disclosure. Actuation element7is operably coupled to inner conductor16and movable along a track9disposed at least partially along the length of handle portion13to move inner conductor16relative to outer conductor20. More specifically, distal actuation of actuation element7along track9deploys or extends inner conductor16from outer conductor20and proximal actuation of actuation element7along track9retracts inner conductor16within outer conductor20.

As seen inFIG. 2A, inner conductor16includes a distal tip17and is extendable from outer conductor20. Several types of inner conductors16may be used in connection with the disclosed ablation device10, including an inner conductor configured to deploy substantially in-line with outer conductor20(e.g.,FIG. 2A) and an inner conductor configured to deploy in a curved orientation (e.g.,FIG. 2B) along a curvilinear path to define an ablation region29. In the illustrated embodiments ofFIGS. 2A and 2B, a proximal end of feedline14includes a coupler18that electrically couples antenna12to generator22via power transmission cord21.

In some embodiments, distal tip17allows for insertion of antenna12into tissue with minimal resistance. In those cases where the antenna12is inserted into a pre-existing opening, distal tip17may be rounded or flat.

As shown inFIG. 2C, feedline14may be in the form of a coaxial cable. Portions of feedline14may be formed of outer conductor20surrounding inner conductor16. Each of inner conductor16and/or outer conductor20may be made of a suitable conductive metal that may be semi-rigid or flexible, such as, for example, copper, gold, or other conductive metals with similar conductivity values. Alternatively, portions of each inner conductor16and outer conductor20may also be made from stainless steel that may additionally be plated with other materials, e.g., other conductive materials, to improve conductivity or decrease energy loss.

With continued reference toFIG. 2C, feedline14of antenna12is shown including a dielectric material28surrounding at least a portion of a length of inner conductor16and outer conductor20surrounding at least a portion of a length of dielectric material28and/or inner conductor16. That is, dielectric material28is interposed between inner conductor16and outer conductor20, to provide insulation therebetween and is comprised of any suitable dielectric material.

With reference toFIGS. 3A and 3B, antenna12may be embodied having a straight probe configuration of radiating portion12, as shown inFIG. 3A, or a loop probe configuration of radiating portion12, as shown inFIG. 3B. In either scenario, radiating portion12includes a lumen26defined coaxially therethrough and at least partially along the length thereof. Disposed within lumen26is an imaging device30adapted to image a desired ablation area. An electrical lead31electrically connects imaging device30to a processing unit24configured to process data generated by imaging device30for representation on a display (see, e.g.,FIGS. 2A,2B). Although not shown entirely in the accompanying figures, lead31is connected to processing unit24and extends therefrom through handle assembly13and lumen26to connect to imaging device30. Processing unit24may include a processor operably coupled with a memory (not shown) that stores suitable image processing software executable as programmable instructions by the processor to cause processing unit24to generate an image based on imaging data received from imaging device30. Processing unit24may be a stand-alone device or may be incorporated within generator22. Imaging device30may be, for example, an ultrasound transducer adapted to generate and receive sound waves to generate imaging data corresponding to the tissue area surrounding radiating portion12. In other embodiments, imaging device30may be, for example, a CAT scan device, a PET scan device, an X-ray device, an MRI device, or other tomographic or X-ray device utilized to generate imaging data corresponding to the desired ablation area.

Imaging device30may be fixedly mounted within lumen26(e.g., via adhesive, fastener, etc.) or may be slidably disposed within lumen26such that imaging device30may be moved proximally and distally within lumen26and/or rotated about longitudinal axis X-X of radiating portion12to facilitate 360 degree and/or radial imaging of surrounding tissue along the entire length of inner conductor16. This configuration of imaging device30makes three-dimensional imaging of the desired tissue site possible. With this purpose in mind, ablation device10may also by rotated 360 degrees by the user to achieve three-dimensional imaging of the desired tissue site.

In another embodiment shown inFIGS. 4A and 4B, imaging device30may be used in conjunction with an introducer50to facilitate placement of radiating portion12relative to an ablation area or a tumor “T”. Introducer50includes a shaft52extending from a proximal hub54to a distal end58, and a lumen56disposed coaxially through shaft52from proximal hub54distally toward distal end58through at least a portion of the length of shaft52. Distal end58may be tapered to allow for insertion of introducer50into tissue with minimal resistance. Shaft52is inserted into tissue of a patient “P” until distal portion58of shaft52is positioned adjacent to or within an ablation area of tissue, e.g., tumor “T”, as shown inFIGS. 4A and 4B. Imaging device30is utilized to image the area surrounding distal portion58of shaft52to ensure that introducer50is properly placed relative to the ablation area. More specifically, imaging data relating to the ablation area is received and processed by processing unit24for viewing by the surgeon. Based on the generated imaging data, the user may maneuver or re-position the introducer50within the patient “P”, if necessary, to ensure accurate position of distal portion58of shaft52relative to tumor “T” before ablation thereof. As illustrated by rotational arrow “A” ofFIG. 4A, introducer50may be rotated about the longitudinal axis of shaft52such that imaging device30may be rotated 360 degrees to completely image the ablation area.

Once introducer50is desirably positioned, ablation device10may then be inserted within lumen56while maintaining the position and orientation of shaft52within patient “P”. Ablation device10is advanced distally within lumen56such that radiating portion12of device10is adjacent to or within tumor “T”. The length of radiating portion12may be configured to fit within shaft52such that a proximal end of handle portion13and proximal hub54contact one another in a lock-fit manner (not explicitly shown). During and/or after an ablation procedure, the ablation area may be imaged to enable the user to monitor the progress and/or completeness of the ablation.

In the illustrated embodiment ofFIGS. 4A and 4B, imaging device30is shown without electrical lead31to illustrate that imaging device30may be configured to communicate imaging data to processing unit24wirelessly from within patient “P”. As such, an electrical lead (e.g., lead31) connecting imaging device30to processing unit24may not be necessary to effect proper and intended implementation of any of the embodiments disclosed herein.

In use, energy (e.g., microwave energy) generated by generator22in close proximity to imaging device30may cause interference with image data generated by imaging device30during an imaging procedure. In this scenario, imaging device30and generator22may be configured, in certain embodiments, to automatically operate in mutual exclusion relative to one another. More specifically, generator22continuously receives and processes an imaging signal generated by imaging device30(e.g., wirelessly) and/or processing unit24that continuously indicates in real-time whether or not an imaging procedure is currently being performed by imaging device30. Based on the generated signal, generator22terminates energy output during an imaging procedure and continues energy output while no imaging procedure is being performed by the imaging device30. In this manner, imaging procedures and electrosurgical procedures (e.g., microwave ablation) may be performed in close proximity and essentially during the same procedure or operation without adverse effects (e.g., image distortion) to the imaging process caused by interference from the output of generator22.

Those skilled in the art will appreciate that imaging device30and/or processing unit24include suitable circuitry (e.g., processor, memory, aid converter, etc.) configured to generate the imaging signal as output and, further, that generator22includes suitable circuitry configured to receive and process the imaging signal as input. In some embodiments, processing unit24and/or ablation device10may include buttons, switches, actuators, or the like, configured to activate or deactivate imaging device30and/or to generate a signal to generator22indicating the activation, suspension, and/or termination of an imaging procedure.

While several embodiments of the disclosure have been shown in the drawings and/or discussed herein, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. For example, it should be understood that any of the above disclosed embodiments may be configured such that imaging device50generates a logic low to indicate an imaging procedure is currently being performed and, vice-versa, a logic high may indicate that no imaging procedure is currently being performed. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.