Patent Description:
Some cryosurgical systems use Magnetic-Resonance Imaging systems for imaging a patient, for instance to guide the cryoprobes during insertion and/or to obtain images of anatomical features (e.g., tissue, tumor, and the like). An example of such systems can be found in <CIT>. Such systems may be desirable in situations where other imaging systems (such as Computed Tomography) may not be suitable (for instance, if exposure to radiation is not desired). However, placement of the cryosurgical system (having electrically-conductive components) in the vicinity of an MRI system may result in noise and/or electrical interference between the cryosurgical system and the MRI system. Some cryosurgery systems have sought to reduce this problem by separating MRI sensitive components from the rest of the system, for example by operating some control components remote from the MRI magnet.

If multiple cryosurgical tools (e.g., cryoprobes) are connected to the system, the presence of electrically-conductive elements, such as metallic probe shafts, in a time-varying magnetic field (generated by the MRI system) may introduce unwanted currents when they are placed inside a patient. In some instances, the magnitude of these currents may be sufficient to stimulate a nerve, leading to undesirable effects such as spasms or twitching during MRI-guided cryosurgery.

Moreover, some cryosurgical systems may include electrical components such as electrical heaters positioned within the probe shaft of each cryoprobe to thaw tissue after a freezing cycle or to facilitate removal of the cryoprobe from the tissue; or temperature sensors for measuring the temperature of the needle. In such systems, there is a possibility that manufacturing defects or damage due to mishandling may lead to electrical components contacting (e.g., shorting) with the probe shaft. This may lead to electrical signals of undesirable frequencies introduced into the cryosurgery system.

There is a need therefore to provide improved cryosurgical systems, with greater usability in proximity to MRI imaging systems.

Documents <CIT> and <CIT> are examples of cryosurgery systems including cryprobes.

The invention is defined in appended independent claim <NUM>. Further embodiments are defined in appended dependent claims.

In an aspect, this disclosure is directed to a cryosurgery system, comprising two or more cryoprobes. Each cryoprobe includes a probe shaft having a distal section insertable in a patient. Each probe shaft can comprise an electrically-conductive material and can be configured to receive a cryofluid from a cryofluid source for cooling and/or freezing the patient's tissue. A proximal coupler of the cryoprobe is in electrical communication with a corresponding probe shaft. Two or more connection ports can each permit connections to a corresponding cryoprobe. Connection ports may be connected to housing portions. Each connection port can be fluidly connected to a cryofluid supply line. The system can have one or more electrical insulators which insulate the proximal couplers from each other when they are connected to the connection ports. Each connection port can have an electrical isolator which can be between the proximal coupler and the connection port when the proximal coupler of the respective cryoprobe is inserted in the connection port. The electrical isolator can be a sleeve, which can include an electrically insulating material so as to electrically isolate each cryoprobe connected to its corresponding connection port from other cryoprobes connected to their corresponding connection ports.

In a first embodiment, the present invention provides a cryosurgery system, comprising a first cryoprobe and a second cryoprobe, the first cryoprobe and the second cryoprobe each including a probe shaft, having a distal section insertable in a patient each probe shaft comprising an electrically-conductive material and configured to receive a cryofluid for cooling and/or freezing the patient's tissue, and a proximal coupler at least a portion of the proximal coupler being electrically conductive, the proximal coupler being in electrical communication with the probe shaft; a first connection port configured to receive and connect to the proximal coupler of the first cryoprobe and a second connection port being configured to receive and connect to the proximal coupler of the second cryoprobe, the first connection port and the second connection port each being fluidly connected to a cryofluid supply line for receiving the cryofluid from a cryofluid source and delivering the cryofluid to the proximal coupler of the first cryoprobe and the proximal coupler of the second cryoprobe respectively; the electrically conductive portion of the proximal coupler of the first cryoprobe being insertable into the first connection port, and the electrically conductive portion of the proximal coupler of the second cryoprobe being insertable into the second connection port; and at least one electrical isolator configured to electrically isolate the proximal coupler of the first cryoprobe from the proximal coupler of the second cryoprobe; such that the probe shaft of the first cryoprobe shaft is substantially electrically isolated from the probe shaft of the second cryoprobe.

In some such systems there exists an electrical connection between the first connection port and the second connection port, as described in more detail below.

It is preferred that the system comprises a plurality of such cryoprobes and proximal couplers, as described herein, in this case, the system comprises one or more electrical isolators configured to electrically isolate the proximal couplers of each cryoprobe from that of every other cryoprobe. Particularly, the system comprises at least one electrical isolator per proximal coupler, configured to electrically isolate the proximal coupler of each cryoprobe from the proximal coupler of every other cryoprobe, thereby electrically isolating the probe shaft of each cryoprobe form the probe shaft of every other cryoprobe.

A further embodiment provides a cryosurgery system, comprising a plurality of cryoprobes, each cryoprobe having a probe shaft comprising an electrically-conductive material, the probe shaft being in electrical communication with a proximal coupler; each proximal coupler configured to be received by and couple to a connection port; and one or more electrical isolators configured to electrically isolate each proximal coupler of a cryoprobe from the connection port of every other cryoprobe coupler.

In some cryosurgical systems, the connection ports are or remain, in electrical communication as described below. Thus, in a second embodiment the invention provides a cryosurgery system, comprising a first cryoprobe and a second cryoprobe, the first cryoprobe and the second cryoprobe each including a probe shaft, each probe shaft comprising an electrically-conductive material and configured to receive a cryofluid for cooling and/or freezing the patient's tissue, and a proximal coupler being in electrical communication with the probe shaft; a first connection port configured to receive and connect to the proximal coupler of the first cryoprobe for placing the first cryoprobe in fluid communication with a source of cryofluid, and a second connection port being configured to receive and connect to the proximal coupler of the second cryoprobe, for placing the second cryoprobe in fluid communication with a source of cryofluid, the first connection port being in electrical communication with the second connection port; and an electrical isolator configured to electrically isolate the proximal coupler of the first cryoprobe from the electrical connection between the first and second connection ports.

It is preferred that the system comprises a plurality of such cryoprobes, proximal couplers and connection ports, as described herein, in this case, the system comprises one or more electrical isolators configured to electrically isolate the proximal couplers of each cryoprobe from the electrical connection between its associated connection port and every other connection port. Particularly, the system comprises at least one electrical isolator per proximal coupler, configured to isolate the proximal couplers of each cryoprobe from the electrical connection between its associated connection port and every other connection port, thereby electrically isolating the probe shaft of each cryoprobe from the probe shaft of every other cryoprobe.

In a third embodiment is provided a cryosurgery system, comprising a plurality of cryoprobes arranged in a cryoprobe group each cryoprobe in the cryoprobe group having a probe shaft comprising an electrically-conductive material the probe shaft being in electrical communication with a proximal coupler; each proximal coupler configured to be received by and couple to a connection port; the connection port being in electrical communication with each other connection port of a cryoprobe in the cryoprobe group; and one or more electrical isolators configured to electrically isolate each proximal coupler of a cryoprobe in the cryoprobe group from the connection port of every other cryoprobe coupler of a cryoprobe in the cryoprobe group.

Typically, cryosurgery systems described herein will be cryoablation systems. Such systems typically comprise a plurality of cryoprobes, for example <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM><NUM>, <NUM> or more needles. The needles may be grouped together as a cryoprobe group, which comprises at least two cryoprobes, but may comprise <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM><NUM>, <NUM> or more needles, whose shafts are electrically isolated from each other.

Typically, the cryosurgery systems described herein further comprise a control system that permits supply of the cryofluid to the first cryoprobe and/or the second cryoprobe so as to selectively freeze a tissue. Typically the cryoprobe shafts comprise an electrically conductive material such as a metallic material. A substantial portion of the probe shaft may comprise a metallic material, for example, the whole shaft of the needle can be of a metallic material, e.g., stainless steel. The tips of the needles may also be made of similar material to the shafts.

Typically, fluid connection lines connect the cryoprobes to the proximal couplers and place the proximal coupler in electrical connection with the cryoprobe shaft. The shafts of the cryoprobes are in electrical communication with the proximal coupler because the fluid connection lines are electrically conductive. They are typically required to deliver cryofluid, such as gas, at high pressure and so made of a flexible metallic material, such as a flexible stainless steel. These lines are configured to receive a cryofluid from a cryofluid source and to transfer the cryofluid from the cryofluid source to the cryoprobe for cooling and/or freezing the patient's tissue.

The proximal coupler and the probe shaft are typically both electrically conductive. The proximal coupler is typically in male format, and couples to a female connection port, although a female proximal coupler configured to couple to a male connection port is also possible. The proximal coupler and the probe shaft are each electrically-conductive.

The connection port is configured to receive and couple to the proximal coupler. Each connection port is in fluid communication with a cryofluid supply line, terminating in a connection port cryofluid opening. The connecting port is configured to place the cryoprobe in fluid communication with the cryofluid source, when the proximal coupler is coupled to the port. The connection port is typically adapted to provide a connection that is capable of providing a gas tight connection at high pressures. As used herein, the term "high-pressures" as applied to a gas is used to refer to gas pressures appropriate for Joule-Thomson cooling of cryoprobes and is typically between <NUM> psi and <NUM> psi.

The connection port is typically in a female connection port configured to receive a male proximal coupler, although a male port adapted to receive a female proximal coupler is also possible.

Female connection ports typically comprise a cavity bounded by an outer wall, having an open end to receive a proximal coupler of a cryoprobe and a connection port cryofluid opening in the outer wall providing a fluid path for a cryofluid to place the cryoprobe in fluid connection with the source of cryofluid.

Male connection ports typically provide a protrusion configured to be received by a female proximal coupler and a connection port cryofluid opening providing a fluid path for a cryofluid to place the cryoprobe in fluid connection with the source of cryofluid.

The connection port cryofluid opening may be closed by a valve whose open condition places the cryoprobe in fluid connection with the source of cryofluid. The valve may be actuated by connection of the proximal coupler to the connection port or may be actuated separately after connection. The connection port may comprise a sealing arrangement cooperating with the proximal coupler to provide a seal that is typically gas tight at high pressure.

There may also be provided a locking mechanism associated with the connection port which holds the union between the connection port and the proximal coupler closed. Such mechanisms can include threaded connectors, over center locking mechanisms or mechanisms in which a spiral groove engages a peg, where rotation of the groove relative to the peg draws the mechanism closed.

In conventional cryosurgery systems, connection ports may be in electrical communication with each other. Typically, this is because each connection port is incorporated into or attached to a housing or housing portion, with which it is in electrical communication. Alternatively, the connection ports may be electrically connected by some other means, such as through mutual connection to another electrically conductive element, such as part of the instrument casing, or through an electrical circuit.

Connecting ports may be arranged in a connecting port group, to connect with a cryoprobe group. A connecting port group is a collection of connecting ports whose corresponding cryoprobes, when connected to the ports, are electrically isolated from each other.

The connection port described herein may be part of a housing, the housing itself typically comprises at least a first housing portion and a second housing portion, each housing portion having a connection port. The housing portions may be connected together to form a unitary housing, or manifold, which comprises a plurality of connection ports. Alternatively, the housing portions may be separated.

Such manifolds form a further embodiment of the invention, which provides a unitary manifold for a cryosurgery system comprising a plurality of connection ports as described herein, each connection port being electrically isolated from the other as described herein.

Where connection ports are electrically connected, this may be as a result of being part of, or connected to, one electrically conductive unitary housing, or manifold, alternatively, the housing portions may be electrically connected by some other means, such as through mutual connection to another electrically conductive element, such as part of the instrument casing, or through an electrical circuit. Typically the manifold comprises at least two connection ports, but may comprise more, for example up to <NUM>, <NUM>, <NUM><NUM><NUM> or more ports.

The manifold may be part of a control system, typically for use remote from an MRI magnet which may additionally comprise components which are not shielded from the effect of operating in proximity with an MRI magnet, or whose functioning may be adversely affected by being close to the MRI, such as microprocessors, computer memory, magnetic storage devices, such as disc drives, etc..

Advantageously, the manifold can be provided as part of a separate connector interface positionable, in use, proximal to the MRI magnet (where MRI sensitive equipment would be adversely affected) within the operating room to permit a plurality of surgical tools such as cryoprobes to be fluidly connected to the cryofluid supply, via an MRI operating room cryofluid supply line. This arrangement isolates parts of the cryosurgery system that may be adversely affected by the MRI magnet and permits them to be placed in a control room remote from the magnet.

The manifold may include a planar surface from which the connection ports can be recessed. The manifold may also include a manifold cryofluid supply line defined as a channel therewithin and in fluid connection with connection port cryofluid openings. In one preferred arrangement, the manifold includes a single common manifold cryofluid supply line common to all connection ports. Alternatively, the manifold may include two or more such supply lines. Each connection port is fluidly connected to the manifold cryofluid supply line such that cryofluid from the cryofluid source is conveyed by the cryoprobe fluid connection lines. The manifold is supplied with cryofluid by one or more cryofluid supply lines.

In a further embodiment, therefore is provided a connector interface for a cryosurgery system for connecting one or more cryofluid supplies, for example in an operating room, to one or more cryoprobes, each cryoprobe having a probe shaft and proximal coupler for coupling the cryoprobe to a connection port, the connector interface comprising: a plurality of connection ports, which may be arranged in a connecting port group, each connection port being connectable to the proximal coupler of a corresponding cryoprobe to place the needle in fluid communication with the cryofluid supply; a plurality of electrical isolator configured to electrically isolate each cryoprobe proximal coupler from every other cryoprobe proximal coupler when coupled the respective connection port of the connecting port group; one or more cryofluid supply lines in fluid communication with the connecting ports; and an operating room cryofluid supply line coupler for connecting an operating room cryofluid supply line and placing the one or more cryofluid supply lines in fluid communication with a cryofluid supply.

In a further embodiment is provided a connector interface for a cryosurgery system for connecting one or more cryoprobes, to a cryofluid supply, each cryoprobe having a probe shaft and proximal coupler for coupling the cryoprobe to a connection port, the connector interface comprising a plurality of connection ports, each connection port being connectable to the proximal coupler of a corresponding cryoprobe to place the needle in fluid communication with the cryofluid supply, one or more of the connection ports comprising an electrical isolator configured to insulate the proximal coupler of a cryoprobe from the connection port; and an electrical circuit configured to detect and/or quantify an electrical potential on the probe shaft or detect an electrical interaction between the probe shaft and an electrical component within the cryoprobe.

The electrical circuit may comprise a sensor configured to be in electrical communication with each corresponding cryoprobe shaft as described herein when a proximal coupler of a cryoprobe is connected to its respective connection port.

In a preferred arrangement, the connection ports and the cryofluid supply lines are arranged as a manifold as described above.

The electrical isolator is generally configured to electrically isolate the proximal coupler of the first cryoprobe from the proximal coupler of the second cryoprobe, such that the first cryoprobe shaft is substantially electrically isolated from the second cryoprobe shaft. The electrical isolator may achieve this in a number of ways. For example, it could be achieved by electrically isolating the connection ports from each other, such as by isolating housing portions comprising a connection port from each other; or by isolating the connection port from the housing portion; or by isolating the proximal couplers from the connection ports. Any combination of these approaches may also be used.

Where connection ports are in electrical connection (for example where the ports are part of a unitary housing or a manifold) the electrical isolator is preferably configured to isolate the proximal coupler from the electrical connection between the ports. This can be achieved, for example, when the connection port comprises an electrical isolator (such as an electrically isolating sleeve), configured to electrically isolate the port from the proximal coupler, or where the proximal coupler comprises an electrical isolator configured to isolate the proximal coupler from the connection port upon connection. When the connection port comprises an electrical isolator, this is preferably in the form of a sleeve, isolating the connection port from the proximal coupler when they are connected. Preferably, the sleeve isolates the outer wall of the connection port from the proximal coupler when they are connected. Preferably, the sleeve covers a substantial portion of an interior surface area of the corresponding connection port.

The isolating sleeve comprises an electrically insulating material such as an electrically non-conductive polymer, such as glass-fiber reinforced polyether ether ketone (PEEK). However, many types of electrically insulating materials can be suitable for use.

Typically all ports comprise an electrical isolator such that all couplers and thereby all probe shafts are isolated from each other.

Electrical isolators (such as an isolating sleeve) as described herein may be discontinuous, for example, they comprise discontinuities such as apertures to permit measurement of electrical signals associated with a proximal coupler connected to the corresponding connection port or to permit a sensor to detect and/or quantify an electrical potential, resistance or current on the proximal coupler or to measure electrical resistance between the shaft of the cryoprobe and an electrical component within the cryoprobe as will be described further below.

Where the connection port comprises a valve, the proximal coupler is optionally electrically isolated from the valve. It is preferred that both the valve as described herein, and the proximal coupler are electrically isolated from the electrical connection between the connection ports by an electrical isolator, preferably by the same electrical isolator, which is preferably in the form of a sleeve isolating the outer wall of the connection port from both the proximal coupler and the valve. The sleeve may therefore be positioned such that when the proximal coupler of the first cryoprobe is connected to the first connection port, the electrical isolator is positioned between the flow control valve connected to the proximal coupler and walls of the first connection port.

To electrically isolate the cryoprobe shafts from each other, it is also possible to provide cryoprobes as described herein, whose proximal coupler comprises an electrical isolator configured to electrically isolate the proximal coupler from the connection port. A further embodiment of the invention therefore provides a cryoprobe having a probe shaft comprising an electrically conductive material and a proximal coupler for coupling the cryoprobe to a connection port for placing the needle in fluid communication with a source of cryofluid, the cryoprobe shaft being in electrical communication with the proximal coupler; the proximal coupler comprising an electrical isolator configured to electrically isolate the proximal coupler of the cryoprobe from the proximal coupler of a second cryoprobe on connection, for example, by isolating the proximal coupler from the connection port.

Electrical components such as heaters and temperature sensors within the cryoprobe shaft, typically receive current from a supply remote from the cryoprobe itself. It is advantageous to be able to detect and quantify the presence of electrical potentials or other electrical signals on the cryoprobe shaft or proximal coupler, and also to detect and quantify the presence of electrical interactions such as unwanted shorts between these electrical components in the cryoprobes, and the probe shafts. The systems described herein therefore may have an electrical circuit configured to detect and/or quantify an electrical potential or other electrical signal on the proximal coupler of the first or second cryoprobe or to detect an electrical interaction between the probe shaft of the cryoprobe and an electrical component within the cryoprobe, as described further below. The electrical circuit can comprise for example, an electrically conductive probe, electrically isolated from the connection port and in electrical connection with the proximal coupler as also described further below.

Thus, in another aspect, the cryosurgery system comprises at least one cryoprobe having an electrical component within the probe shaft. In this aspect, a connector interface having one or more connection ports, each being connectable to the proximal coupler of the corresponding cryoprobe. An electrical measurement system can be connected to each connection port. The electrical measurement system can detect electrical signals associated with the probe shaft. The system also includes a control system configured to detect, based on the electrical signals detected by the electrical measurement system, whether the probe shaft is electrically connected to the electrical heater.

In a further aspect, the connector interface comprises a plurality of electrical resistance measurement systems, each of which is electrically coupled to a corresponding connection port. Each electrical resistance measurement system can be configured to measure electrical resistance between the electrical heater and the probe shaft of the corresponding cryoprobe connected to the corresponding connection port. Each electrical resistance measurement system has electrically-conductive resistance measurement elements that contact at least a portion of the corresponding cryoprobe and thereby be electrically connected with the probe shaft of each corresponding cryoprobe.

Thus, a further aspect provides a cryosurgery system, comprising a cryoprobe having a probe shaft comprising an electrically-conductive material, the probe shaft being in electrical communication with a proximal coupler; the proximal coupler configured to be received by and couple to a connection port for placing the cryoprobe in fluid communication with a cryofluid source; and an electrical sensor configured to detect and/or quantify an electrical potential on the probe shaft or an electrical connection between the shaft and an electrical component within the cryoprobe.

The approach is particularly suitable for use with embodiment and aspects of the invention as described above, such as cryosurgery systems, needles, manifolds and connection interfaces comprising an electrical isolator. Thus, a further embodiment provides cryosurgery systems, cryoprobes manifolds and connection interfaces as described herein, comprising one or more sensors configured to detect and/or quantify an electrical potential or other electrical signal on the probe shaft or to detect and/or quantify an electrical connection between the shaft of the cryoprobe and an electrical component within the cryoprobe.

Conveniently, such sensors are configured to detect and/or quantify an electrical potential or other electrical signal on the proximal coupler(s) of cryoprobe(s) as described herein. A sensor system for this purpose comprises one or more sensors, and may also comprise electrical circuits for the measurement of current, resistance, or voltage and/or one or more control systems configured to determine the presence of a signal indicative of an electric potential on the cryoprobe shaft or a short between the shaft and an electrical component within the cryoprobe. The controller may report either or both of these as an error state and/or shut down the electrical component of the needle or needles, for example.

Such sensors may be configured to be in electrical communication with the cryoprobe shaft. In one approach, the sensor comprises an electrically conductive probe, electrically coupled to a corresponding probe shaft so as to measure electrical signals of the probe shaft. The probes are preferably in electrical connection with the proximal coupler, either directly, such as by touching the coupler, or indirectly, such as by touching the valve which is in electrical contact with the coupler. Probes are preferably electrically isolated from the connection port.

In one embodiment the probe can be an electrically conductive balls or bearings, resiliently biased, held in direct or indirect electrical communication with the coupler by a spring loaded pogo pin.

Typically, the sensor connects to circuitry for measuring an electrical signal on the pin or to detect and or quantify an unwanted circuit between the pin and an electrical component within the needle, to provide a system for detecting unwanted electrical signals on the probe shaft or to detect a short between an electrical component in the needle and the probe shaft.

A further particularly preferred embodiment provides a cryosurgery system, comprising a first cryoprobe and a second cryoprobe, the first cryoprobe and the second cryoprobe each including, a probe shaft, each probe shaft comprising an electrically-conductive material and configured to receive a cryofluid for cooling and/or freezing the patient's tissue, and a proximal coupler being in electrical communication with the probe shaft; a first connection port configured to receive and connect to the proximal coupler of the first cryoprobe and a second connection port being configured to receive and connect to the proximal coupler of the second cryoprobe, and an electrically isolating sleeve within the first and second connection ports, the electrically isolating sleeves configured to electrically isolate the proximal coupler of the first cryoprobe from the proximal coupler of the second cryoprobe; such that the first cryoprobe shaft is substantially electrically isolated from the second cryoprobe shaft.

A further preferred embodiment provides a cryosurgery system, comprising a plurality of cryoprobes each cryoprobe having a probe shaft comprising an electrically-conductive material the probe shaft being in electrical communication with a proximal coupler; each proximal coupler configured to be received by and couple to a connection port; and an electrically isolating sleeve within each connection port configured to electrically isolate each proximal coupler of a cryoprobe from the connection port of every other cryoprobe coupler.

A particularly preferred embodiment provides a cryoablation surgery system, comprising a first cryoprobe and a second cryoprobe, the first cryoprobe and the second cryoprobe each including, a probe shaft, each probe shaft comprising an electrically-conductive material and configured to receive a cryofluid for cooling and/or freezing the patient's tissue, and a proximal coupler being in electrical communication with the probe shaft; a first connection port configured to receive and connect to the proximal coupler of the first cryoprobe for placing the first cryoprobe in fluid communication with a source of cryofluid, and a second connection port being configured to receive and connect to the proximal coupler of the second cryoprobe, for placing the second cryoprobe in fluid communication with a source of cryofluid, the first connection port being in electrical communication with the second connection port; and an electrically isolating sleeve within the connection port configured to electrically isolate the proximal coupler of the first cryoprobe from the electrical connection between the first and second connection ports.

A further particularly preferred embodiment provides a cryosurgery system, comprising a plurality of cryoprobes arranged in a cryoprobe group each cryoprobe in the cryoprobe group having a probe shaft comprising an electrically-conductive material the probe shaft being in electrical communication with a proximal coupler; each proximal coupler configured to be received by and couple to a connection port; the connection port being in electrical communication with each other connection port of a cryoprobe in the cryoprobe group; and an electrically isolating sleeve within each connection port configured to electrically isolate each proximal coupler of a cryoprobe in the cryoprobe group from the connection port of every other cryoprobe coupler of a cryoprobe in the cryoprobe group.

A further particularly preferred embodiment provides a cryosurgery system, comprising a first cryoprobe and a second cryoprobe, the first cryoprobe and the second cryoprobe each including, a probe shaft, each probe shaft comprising an electrically-conductive material and configured to receive a cryofluid for cooling and/or freezing the patient's tissue, and a proximal coupler being in electrical communication with the probe shaft; a first connection port configured to receive and connect to the proximal coupler of the first cryoprobe and a second connection port being configured to receive and connect to the proximal coupler of the second cryoprobe, and an electrically isolating sleeve within each connection port configured to electrically isolate the proximal coupler of the first cryoprobe from the proximal coupler of the second cryoprobe; such that the first cryoprobe shaft is substantially electrically isolated from the second cryoprobe shaft.

Cryosurgical systems can be used for cryoablating target tissues (e.g., a tumor). Typically, such systems include one or more cryoprobes, one or more cryofluid sources <NUM> and a controller. The cryofluid sources <NUM> can supply gases such as argon, nitrogen, air, krypton, CO<NUM>, CF4, xenon, and various other gases. As used herein, "cryofluid" can refer to any fluid that reaches low temperatures (e.g., below <NUM> Kelvin). In some non-limiting exemplary embodiments, the fluid can reach low temperatures (e.g., below <NUM> Kelvin) when pressurized to pressures greater than about <NUM> psi (e.g., typically around <NUM> psi) and permitted to undergo Joule-Thomson expansion, as will be described further below. The cryosurgical system can also include a controller having one or more sensors, flow meters, timers, analog/digital converters, wired or wireless communication modules, etc. Additionally, the controller can also regulate the flow rate, temperature, and pressure of cryofluid supplied to the cryoprobe <NUM>.

During cryosurgery, for instance, a surgeon may deploy one or more cryoprobes to cryoablate a target area of a patient <NUM> anatomy by placing the cryoprobe <NUM> at or near the target area of the patient <NUM> anatomy. In one example, cryoprobe <NUM> utilizes the Joule-Thomson effect to produce cooling or heating. In such cases, a cryofluid expands in the cryoprobe100 from a higher pressure to a lower pressure. Expansion of the cryofluid results in temperatures at or below those necessary for cryoablating a tissue in the vicinity of the tip of the cryoprobe <NUM>. Heat transfer between the expanded cryofluid and the outer walls of the cryoprobe <NUM> can be used to form an iceball, and consequently cryoablate the tissue.

<FIG> is a schematic of a Magnetic Resonance Imaging (hereinafter "MRP")-guided cryosurgery system <NUM> according to a non-limiting exemplary embodiment. The system of <FIG> can include a magnet room <NUM> comprising a MRI scanner <NUM> comprising a MRI magnet <NUM> for accommodating a patient <NUM>. The MRI magnet <NUM> can be of open or closed type, and can include access ports to allow a surgeon to access the patient <NUM>. The MRI magnet <NUM> can also have electrical connection lines (illustrated by solid lines) and/or mechanical connection lines (illustrated by dashed lines) in <FIG> for connecting to various electrical, control and/or cryoablation systems as will be described further below. The system can also include a control room <NUM> electrically (and/or magnetically) isolated from the magnet room <NUM> (as shown in <FIG> by electrical and/or magnetic isolation <NUM>), and an equipment room <NUM>. The MRI system may be used to image the patient before insertion of surgical tools to visualize patient areas of interest, such as a tumor or a patient cavity. Further, imaging may be performed during insertion to guide the surgical tool to the intended location inside the patient. Additionally, imaging may be performed after insertion and during surgery, as well as after surgery.

Continuing with <FIG>, in a non-limiting exemplary embodiment, the connection lines may terminate in one or more surgical tools <NUM>, such as cryoprobes insertable inside a patient <NUM>. Accordingly, in some such examples, the system may include a connector interface <NUM> placed inside the magnet room <NUM> to permit connection of one or more surgical tools <NUM>, <NUM>, <NUM> to other components of the cryoablation systems that may be placed outside the magnet room <NUM> (for instance, in a control room or an equipment room). For instance, the system may include electrical connection lines and fluid connection lines extending from the control room to the magnet room <NUM>, so as to operatively connect a control system <NUM> to the surgical tools <NUM>. The connector interface <NUM> can, in some advantageous embodiments, be provided on a cart <NUM> (which may be stationary or mobile) positioned proximal to the magnet to permit a plurality of surgical tools <NUM> to be directly or indirectly (e.g., electrically and/or fluidly) connected to the control system <NUM> positioned outside the magnet room <NUM> (e.g., in the control room). In the illustrated embodiment, the cart <NUM> is a mobile cart.

The electrical and fluid connections between the control system <NUM> and the surgical tools <NUM> will be described according to an example embodiment. The control system <NUM> can be electrically connected to a junction box <NUM> located external to the magnet room <NUM> by way of a first set of electrical connection lines <NUM>. Further, the junction box <NUM> can include a second set of electrical connection lines <NUM> to connect to electrical and/or imaging equipment <NUM> (such as an imaging router and electrical filters) located external to the magnet room <NUM> (for instance, within the equipment room). A third set of electrical connection lines <NUM> may connect the electrical and/or imaging equipment to the connector interface <NUM> and/or mobile cart <NUM> located inside the magnet room <NUM>. The junction box <NUM> can permit removable electrical connection between components in the magnet room <NUM> and components in the electrical and/or control rooms.

Referring again to <FIG>, in some examples, the system may be used to perform cryosurgical procedures (e.g., cryoablation). Accordingly in some examples, the system may include one or more cryofluid sources <NUM>. The cryofluid source can be a liquid or gas container that can provide a fluid at cryogenic temperatures and pressures to surgical tools <NUM> (e.g., cryoprobes). The cryofluid source can be a cooling gas such as argon, nitrogen, air, krypton, CF<NUM> xenon, or N<NUM>O.

As can be seen from <FIG>, the cryofluid source is positioned outside the magnet room <NUM> and is fluidly connectable to the control system <NUM> by way of a first set of fluid connection lines <NUM>. The control system <NUM> in turn can be fluidly connected to the connector interface <NUM> and/or mobile cart <NUM> by way of a second set of fluid connection lines <NUM> and a third set of fluid connection lines <NUM>. A fourth set of fluid connection lines <NUM> can fluidly connect the surgical tools <NUM> (e.g., cryoprobes) to the connector interface <NUM> and/or mobile cart <NUM>. The fluid lines can be flexible and/or detachable and may include other fluid components to regulate pressure of fluid passing therethrough. Fluid from the cryofluid source may thus be conveyed by the set of fluid connection lines <NUM>, <NUM>, <NUM> and <NUM> to the surgical tools <NUM>. Optionally, the system can include a fluid connection panel <NUM> electrically isolated from the magnet room <NUM> so as to permit fluid connections between components present in the magnet room <NUM> and those in the control room. Similarly, an electrical connection panel <NUM> can facilitate electrical connections between components present in the magnet room <NUM> and those in the control room and/or electrical room.

<FIG> are schematics of the system <NUM> and a mobile cart <NUM> respectively according to a non-limiting exemplary embodiment. Referencing <FIG>, connections of the mobile cart <NUM> and control system <NUM> are illustrated. The control system <NUM> can include a mobile housing <NUM>. As shown in <FIG>, the housing may include an external display <NUM>. Further, a computer (e.g., processor and memory) may be housed within the housing and operatively coupled to the external display <NUM>. The control system <NUM> can control the operation of the MRI-guided cryosurgery system <NUM> according to predetermined operating conditions (e.g., provided as computer-readable programs or instructions) provided by a surgeon (e.g., using input devices such as a keyboard or a touch interface operatively coupled to the control system <NUM>). The external display <NUM> can be used for displaying data relating to the status of each of the surgical tool and other updated data on the procedure being performed. Further, the external display <NUM> may provide information relating to the medical record of a specific patient <NUM>. The control system <NUM> also includes a connection panel <NUM> to electrically and fluidly connect to the connector interface <NUM> positioned on the mobile cart <NUM> located in the magnet room <NUM>. The connection panel <NUM> can include a plurality of ports <NUM> that can be fluidly and/or electrically coupled to ports of a connector interface <NUM> positioned within the magnet room <NUM>. Thus, the control system <NUM> can individually control operation of each surgical tool connected to a port of the connector interface <NUM>, as will be described further.

Referring back to <FIG>, the system also includes a MRI display <NUM> operatively coupled to the MRI scanner <NUM> and positioned within the magnet room <NUM> for displaying an image representative of an anatomical feature of a patient <NUM> so as to provide guidance to a surgeon during surgery. The MRI display <NUM> can be operatively coupled to electrical and/or imaging components in the equipment room and the control system <NUM> located within the control room. Such a configuration may display an image identical to the image displayed on the external display <NUM>, and may include information relating to the operating conditions of the overall system. In such cases, advantageously, the MRI display <NUM> may enable a surgeon to select a desired image, for example, to monitor the progress of the surgical process, images relating to MRI guidance and/or current information relating to one or more surgical tools <NUM>. Optionally, more than one display may be provided in the magnet room <NUM> to permit simultaneous visualization of various aspects of the surgical procedure.

As described earlier, the surgical tool can be a cryoprobe <NUM> in a non-limiting exemplary embodiment. <FIG> is a front view of one such cryoprobe <NUM> and <FIG> is a sectional front view of the cryoprobe <NUM> of <FIG>. Referring to <FIG>, the cryoprobe <NUM> can include an elongate body. Components of the cryoprobe <NUM> can be located within a probe shaft <NUM>. The cryoprobe can, in some cases, be a cryoneedle, in which case, components of the cryoneedle may be arranged interior to a trocar. The probe shaft <NUM> can terminate in a distal operating tip <NUM> disposed at a distal section <NUM> of the cryoprobe <NUM> for penetrating through tissues of a patient <NUM> during deployment. In embodiments where the cryoprobe is configured as a cryoneedle, the distal operating tip <NUM> can penetrate the patient's skin. In alternate embodiments, the cryoprobe can be a flexible probe, and may be inserted by way of a catheter. A proximal coupler <NUM> can facilitate connections of the cryoprobe <NUM> to a connector interface <NUM>, control system <NUM> and/or cryofluid source <NUM>.

The probe shaft <NUM> can be of substantially thin cross section to allow deployment in tissues of a patient <NUM>. In an example, the cryoprobe can be a cryoneedle, having a probe shaft <NUM> outer diameter of about <NUM> millimeters. Other dimensions of the probe shaft <NUM> are also contemplated. For example, the probe shaft <NUM> can have an outer diameter of between about <NUM> millimeters and about <NUM> millimeters. In addition, in embodiments where the cryoprobe is a cryoneedle, the distal operating tip <NUM> can be made of a pliant material so as to be flexible (e.g., relative to the proximal portion of the cryoprobe <NUM>) for penetrating soft tissue. Alternatively, a substantial portion of the cryoprobe can be generally flexible and may not pierce the patient skin, and may be flexible (bendable) about its central axis, by a desired angle.

As seen in <FIG>, the cryoprobe <NUM> includes a cryofluid supply tube <NUM> extending substantially along its length for providing a high-pressure cryofluid to the distal operating tip <NUM>. The cryofluid supply tube <NUM> can be positioned coaxially/concentrically within the probe shaft <NUM>. The cryofluid supply tube <NUM> can be configured to supply a cryofluid for forming iceballs on an outer surface of the probe shaft <NUM> over the distal section <NUM>. In some cases, the cryofluid supply tube <NUM> can be a capillary tube.

With continued reference to <FIG>, in some examples, the cryoprobe <NUM> includes a cryocooler. For instance, in the illustrated example, the cryofluid supply tube <NUM> can terminate in a Joule-Thomson orifice <NUM>. The Joule-Thomson orifice <NUM> can be positioned near the distal operating tip <NUM>, so as to permit cryofluid exiting the Joule-Thomson orifice <NUM> to expand into an expansion chamber. Accordingly, a high-pressure cryofluid supplied via the cryofluid supply tube <NUM> exits through the Joule-Thomson orifice <NUM> and expands in the expansion chamber. As the cryofluid expands in the expansion chamber, it cools rapidly and forms iceballs of different shapes and/or sizes over the outer surface of the distal operating tip <NUM>. The expansion of the cryofluid can be such that when expanded, the cryofluid is colder than the incoming cryofluid. While an exemplary cryocooler such as a Joule-Thomson orifice <NUM> is illustrated, it should be understood that other types of cryocoolers such as cryogenic dewars, Stirling-type cooler, pulse-tube refrigerator (PTR), and/or Gifford-McMahon (GM) cooler are contemplated within the scope of the present disclosure. Further, as briefly noted above, cryofluids which may be used for cooling include argon, liquid nitrogen, air, krypton, CF<NUM>, xenon, or N<NUM>O.

In some advantageous embodiments, the outer surface of the distal operating tip <NUM> can be made of a heat conducting material such as metal for effectively freezing the patient's tissue. In some such examples, the outer surface of the distal operating tip <NUM> can be stainless steel or Inconel <NUM>. Other conductive metals and alloys permitting heat exchange between the distal operating tip <NUM> and the patient tissue are contemplated within the scope of the present disclosure. In addition, a substantial portion of the probe shaft <NUM> may comprise a metallic material. In some such exemplary embodiments, the probe shaft <NUM> can comprise an electrically-conductive material. Further, the proximal coupler <NUM> can also have electrically conductive components (e.g., portions of proximal pin <NUM>) so as to be in electrical communication with a corresponding probe shaft <NUM>.

Referring again to <FIG>, in some examples, a heater <NUM> can optionally be provided within the probe shaft <NUM> to facilitate thawing and/or cauterizing tissue. In some such examples, the heater <NUM> may be operated after cooling and iceball formation to thaw frozen tissue to facilitate disengagement of cryoprobe <NUM> therefrom. As illustrated in this exemplary embodiment, an electrical heater <NUM> can be provided coaxially with the cryofluid supply tube <NUM> and the probe shaft <NUM> to facilitate heating the distal section <NUM> of the cryoprobe <NUM>. Alternatively, the electrical heater <NUM> can be positioned elsewhere in cryoprobe <NUM> to heat the distal section <NUM> of the cryoprobe <NUM>. The electrical heater <NUM> can be a resistive heater <NUM>, wherein the electrical heater <NUM> generates heat proportional to the current flow therethrough and the electrical resistance of electrical heater <NUM>. In such cases, as alluded to previously, the control system <NUM> (shown in <FIG>) can supply and/or regulate electrical current flow to the electrical heater <NUM> within the cryoprobe <NUM>.

In the embodiment illustrated in <FIG>, the electrical heater <NUM> comprises metal wire (e.g., titanium, copper and/or alloys such as nichrome) wound in helical coils (e.g., between about <NUM> coils and about <NUM> coils) around the cryofluid supply tube <NUM>. For instance, the wire can be wound with a negligible pitch between adjacent coils of the wire. Additionally, the wires can substantially contact an outer surface of the cryofluid supply tube <NUM>. The electric heater <NUM> may comprise a material having high resistance. For instance, in some advantageous embodiments, the electric heater <NUM> may have a positive coefficient of electrical resistance such that heat is generated when current passes therethrough. A pair of lead wires may attach to terminal ends of the heater <NUM> wire, to electrically connect the heater <NUM> to the control system <NUM> and supply current thereto. In some such examples, the lead wires, the terminal ends and the heater <NUM> wire may be bonded or otherwise attached to the cryofluid supply tube <NUM>, and spaced apart from the inner surface <NUM> of the probe shaft <NUM> so as to electrically isolate the probe shaft <NUM> (which may be electrically conductive) from the current carrying heater <NUM>.

Further aspects of the cryoprobe <NUM> may permit a temperature monitoring and/or control thereof. For instance, the distal operating tip <NUM> can include at least one thermal sensor for sensing the temperature. Further, the distal operating tip <NUM> can include proximal handles to facilitate manipulation of the cryoprobe <NUM>, for instance, by a surgeon during cryosurgical procedures. Electrical and/or manual controls on the proximal handle may provide manually controlling distal operating tip <NUM> and permit functions such as on/off, heating, cooling, and predetermined cycles of heating and cooling by selectively and controllably communicating with the control system <NUM> and/or cryofluid source. Further, electrical systems may also permit detection of whether a cryoprobe <NUM> is electrically connected to the control system <NUM>.

As described previously with reference to <FIG>, the systems described herein and the MRI-guided cryoablation systems described herein and/or certain components of them are positionable proximate to a magnetic resonance imaging (MRI) system that permits imaging to guide insertion of cryoprobes into the patient, during surgery. For instance, the cryoprobes can be connected to the fourth set of electrical connection lines <NUM> from the mobile cart <NUM>, which in turn can be connected to the connector interface <NUM>. In <FIG>, one of the surgical tools is shown as being connected to the mobile cart <NUM> by way of connection line <NUM>, however, substantially all the surgical tools may be connectable to the mobile cart <NUM> by way of individual connection lines <NUM>.

The cryoprobes, as well as the connector interfaces herein, may include components that are configured to develop reactive effects when exposed to magnetic resonance (MR) signals generated by the MRI system. For example, the metallic material of the probe shaft <NUM> may develop electric or magnetic fields associated therewith. Alternatively, the electric heater <NUM> may develop a force as a result of being used in conjunction with (or exposed to) magnetic fields associated with the MRI system (for instance, the magnetic field generated by the MR magnet), and may detach from its attachment (weld or bond) with the cryofluid supply tube <NUM>. This may lead to undesirable physical or electrical contact (e.g., shorting) between the heater <NUM> and the probe shaft <NUM>.

Further, if two or more cryoprobes are electrically connected, such shorting may generate currents sufficient to stimulate the nerves of a patient <NUM>, and may lead to unintended effects. Accordingly, in some advantageous examples of the present disclosure, the cryoprobes can be electrically isolated from each other. Further, the present disclosure provides an electrical measurement system <NUM> (similar to sensing arrangement <NUM>) to detect electrical signals, and thereby provide additional information indicative of an electrical contact (e.g., shorting) between the heater <NUM> and the probe shaft <NUM>.

<FIG> is a simplified representation of a connector arrangement according to the invention. In this arrangement, two cryoprobes <NUM> are connected, individually to connection ports <NUM> in individual housings <NUM>, <NUM>. The connection ports are in electrical communication with the housings which themselves are in electrical connection <NUM>. As illustrated, the connection ports may refer to receptacles which act as container. The walls of the connection ports thus act as boundaries and define a hollow space to contain portions of the proximal coupler <NUM>, insulating sleeves, and a flow control valve. Alternatively, the connection ports may be a male connector instead of the female receptacle engaging with complementary female connectors on the proximal coupler <NUM>.

Cryoprobe <NUM> having a probe shaft <NUM> and a handle arrangement <NUM> is connected via fluid connection line <NUM> to a proximal coupler <NUM> to the connection port <NUM> within a housing portion <NUM>, <NUM>. The port and housing without the coupler are shown in plan view in <FIG>.

Cryofluid is provided via the manifold <NUM> to the fluid connection line and thence to the cryoprobe <NUM>. From there, it may be vented to the air or returned to the system via another connection. Both the cryoprobe shaft <NUM> and the fluid connection line <NUM> are electrically conductive. The coupler <NUM>, in this case a threaded union, is electrically insulated from the housing portion <NUM> by an electrically insulating member in the form of a sleeve <NUM> positioned between the connection port <NUM>, and the union <NUM> electrically insulates the cryoprobes from each other. <FIG> shows a similar arrangement in which the connection ports are arranged in a common housing <NUM> in which the two housing portions are part of the common housing.

<FIG> illustrates a further embodiment of the invention in which the needles are isolated one from another by an insulating sleeve <NUM>, but a sensing arrangement <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is arranged to measure the electrical potential on the coupler <NUM> and thus the probe shaft <NUM>. In this case the sensing arrangement is a steel ball <NUM>, held against the coupler <NUM> by a spring <NUM>, the arrangement held within a threaded cap <NUM>, which insulates the sensing arrangement from the housing, and hence from the other needle(s). The connection <NUM> is connected to an electrical circuit for measuring the potential on the coupler and hence the needle. The circuit can easily be adapted to measure the resistance between electrical components of the needle and the probe shaft. This can be used to sense unwanted shorts.

<FIG> shows a general view of a connector interface <NUM>, mounted on a trolley <NUM>. Wheels <NUM>, on the bottom of the trolley provide mobility and allow the trolley and the interface to be positioned close to the MRI magnet, whilst other parts of the system remain remote from the MRI. The connector interface rests on a platform <NUM> on top of the trolley. The connector interface <NUM> comprises a casing <NUM>, having a manifold <NUM>, on the front face <NUM>. The manifold comprises six connection ports <NUM>, which in this instance are separated from six electrical ports <NUM>. The connection ports <NUM> connect the proximal connectors of respective cryoprobes to the manifold and allow cryofluid supplied to the connector interface by operating room cryofluid supply line <NUM> to be delivered to the cryoprobes <NUM>. Electrical ports <NUM> connect electrical components within the cryoprobes to cryoprobe electrical lines <NUM>.

<FIG> shows a side view of the connector interface. This view additionally shows cryoprobes <NUM>, which are connected to the manifold <NUM>. The fluid connection lines <NUM> connect to the connection ports by proximal couplers (not shown). Bound alongside the fluid supply line, electrical lines <NUM> connect electrical components of the cryoprobe to the manifold at the electrical port <NUM>. The electrical port is connected via internal electrical line <NUM>, to the operating room electrical lines <NUM>, and thence to the control system. Sensor electrical line <NUM> connects a sensor (not shown, see <FIG>) to electrical sensor lines <NUM> and electrical sensor operating room lines <NUM> that connect the sensor to a control system configured to detect whether the probe shaft is electrically connected to the electrical heater and to detect whether an electrical potential is present on the cryoprobe shaft.

<FIG> is an exploded perspective view of a connector interface <NUM> permitting connection of the cryoprobe <NUM> of <FIG> to the mobile cart <NUM> of <FIG> in accordance with a non-limiting exemplary embodiment, while <FIG> is a sectional front view of a portion of the connector interface <NUM> of <FIG>. The connector interface <NUM> can be substantially similar to the connector interface <NUM> and be provided on the mobile cart <NUM> positionable within the magnet room <NUM>. The connector interface <NUM> includes housing portions in the form of a manifold <NUM> having a connection port <NUM> for connecting to a cryoprobe <NUM>. The manifold <NUM> can include a planar surface <NUM> from which the connection ports can be recessed. As seen in <FIG>, the manifold <NUM> includes a cryofluid supply line <NUM> defined as a channel therewithin. In advantageous embodiments, the manifold <NUM> may include a single common cryofluid supply line common to all connection ports. Alternatively, the manifold <NUM> may include two or more cryofluid supply lines. Each connection port <NUM> can be fluidly connected to the cryofluid supply line <NUM> such that cryofluid from the cryofluid source <NUM> (best seen in <FIG>) is conveyed by the first, second, third and fourth set of fluid connection lines <NUM>, <NUM>, <NUM>, <NUM> to the cryofluid supply line <NUM> (seen in <FIG>). In turn, the cryofluid supply line <NUM> supplies the cryofluid to the cryofluid supply tube <NUM> (best seen in <FIG>) of a cryoprobe <NUM> connected to the corresponding connection port <NUM>.

With reference to <FIG>, in an aspect of the present disclosure, the connector interface <NUM> can electrically isolate two or more cryoprobes connectable thereto. Accordingly, as illustrated in <FIG>, each connection port <NUM> may have an isolating sleeve <NUM> (similar to sleeve <NUM>) including an electrically insulating material so as to electrically isolate each cryoprobe <NUM> connected to its corresponding connection port <NUM> from other cryoprobes connected to their corresponding connection ports. The isolating sleeve <NUM> is positioned such that when each cryoprobe <NUM> is connected to a corresponding connection port <NUM>, the isolating sleeve <NUM> is positioned between the proximal coupler <NUM> inserted into the connection port <NUM> and walls <NUM> of the corresponding connection port <NUM>. In some advantageous embodiments, the isolating sleeve <NUM> can cover a substantial surface area of the walls <NUM> of the connection port <NUM>. For instance, the isolating sleeve <NUM> can occupy between about <NUM>% and about <NUM>% of the interior surface area of the walls <NUM> of the connection port <NUM>. The isolating sleeve <NUM> can have apertures to permit measurement of electrical signals associated with the probe shaft <NUM> of a proximal coupler <NUM> connected to the corresponding connection port <NUM>, as will be described further below.

In some example embodiments, the electrically insulating material of the isolating sleeve <NUM> is an electrically non-conductive polymer. Advantageously, in some such cases, glass-fiber reinforced polyether ether ketone (PEEK) can be used. However, many types of electrically insulating materials can be suitable for use. While the above configuration provides electrical isolation between two connected cryoprobes, in some advantageous examples, an electrical sensing and/or electrical measurement system <NUM> may be provided for each connection port <NUM> so as to detect electrical signals associated with the probe shaft <NUM> and determine whether the probe shaft <NUM> is electrically connected to the electrical heater <NUM>. The electrical sensing and/or measurement system <NUM> (similar to sensing arrangement <NUM>) can be an electrical circuit configured to detect and/or quantify an electrical potential on the proximal coupler, or detect an electrical interaction between the probe shaft of the cryoprobe and the electrical component within the cryoprobe.

<FIG> illustrate various features of the electrical measurement system <NUM>. The electrical measurement system <NUM> comprises electrically conductive elements that can contact a portion of a proximal coupler <NUM> even when isolated by the insulating sleeve. In some exemplary embodiments, only a small portion of the proximal coupler <NUM> may be available to electrically contact the electrical measurement systems so as to provide substantial electrical isolation between adjacent cryoprobes, while still providing the ability to measure electrical signals associated with the probe shaft <NUM>. For instance, between <NUM>% and about <NUM>% of a surface area of the proximal coupler <NUM> can be in contact with components of the electrical measurement system <NUM> when the cryoprobe <NUM> is connected to the connection port <NUM>.

Continuing with <FIG>, the electrical measurement system <NUM> can, in a non-limiting exemplary embodiment, include a plurality of electrical contact pins <NUM>. Each electrical contact pin <NUM> can be electrically coupled to a corresponding probe shaft <NUM> so as to measure electrical signals associated with the probe shaft <NUM>. The electrical contact pin <NUM> can, in the illustrated embodiment, be a pogo pin terminating in a tip <NUM> that can indirectly or directly contact the probe shaft <NUM>. Thus, when a proximal coupler <NUM> of the probe shaft <NUM> is inserted into the connection port <NUM>, the direct or indirect contact of the tip <NUM> of the electrical contact pin <NUM> may electrically connect the electrical contact pin <NUM> with the probe shaft <NUM>. In the illustrated example, the electrical contact pin <NUM> has an indirect contact with the probe shaft <NUM>, as will be described further below. Each electrical contact pin <NUM> can be securely held in a recess <NUM> in the connector interface <NUM> by a non-conductive plug <NUM> at a location suitable to permit the tip <NUM> of the electrical contact pin <NUM> to directly or indirectly contact portions of the proximal coupler <NUM>. In the illustrated example, the recess <NUM> into which the electrical contact pin <NUM> is inserted is positioned on a surface <NUM> perpendicular to the planar surface <NUM> from which the connection ports are recessed.

With continued reference to <FIG>, the electrical measurement system <NUM> comprises a plurality of electrically-conductive bearings <NUM> that can be housed at locations corresponding to openings on the isolating sleeve <NUM>. In the illustrated example of <FIG>, the bearings are positioned to contact components housed in or portions of the connection port <NUM>. For instance, in an example, the electrically-conductive bearings <NUM> contact a flow control valve physically and/or electrically coupled to the proximal coupler <NUM> (as will be described further below), thereby electrically communicating with the proximal coupler <NUM> of the corresponding cryoprobe <NUM>. In an embodiment, the probe shaft <NUM> may be physically coupled to fluid lines that may supply cryofluid to the cryofluid supply tube <NUM> which may be electrically conductive. As a result, when the probe shaft <NUM> is exposed to a MRI field, any current induced into the probe shaft <NUM> may travel to pin <NUM> of the proximal coupler <NUM> (and to the corresponding connection port) by way of the electrically conductive fluid lines. A band-shaped spring <NUM> made of an electrically conductive material may be inserted over the bearings so as to spring-bias the electrically-conductive bearings <NUM> to contact a corresponding connection port <NUM>. Advantageously, the band-shaped spring <NUM> can be a constant force spring. In the illustrated example, an inner surface of the band-shaped spring <NUM> presses against a portion of each bearing at a location opposite (e.g., along the diameter) to the contact between the bearing <NUM> and the flow control valve <NUM>. An outer surface of the band-shaped spring <NUM> can permit (e.g., through openings at positions corresponding to) the tip <NUM> of a corresponding electrical contact pin <NUM> to contact and/or pass therethrough at locations corresponding to the location of the bearings <NUM>.

The band-shaped spring <NUM> is electrically conductive and surrounds a substantial perimeter of the isolating sleeve <NUM>, such that the electrical contact pin <NUM> can contact the band-shaped spring <NUM> and measure electrical signals at substantially any circumferential position. However, the band-shaped spring <NUM> extends over a minimal surface area of the isolating sleeve <NUM> so as to permit the isolating sleeve <NUM> to electrically isolate connected cryoprobes from each other without substantial electrical interference from the electrical measurement system <NUM> housed in each connection port <NUM>.

The electrical measurement system <NUM> can include components that are substantially electrically conductive. For instance, each of the band-shaped spring <NUM>, bearings <NUM> and electrical contact pin <NUM> can be electrically conductive. Accordingly, in some examples, the isolating sleeve <NUM> may have openings to receive the bearings <NUM> so as to permit electrical measurement. The electrically-conductive bearings <NUM> are spring-biased by the band-shaped spring <NUM> to contact a housing <NUM> (at least portions of which is electrically conductive) of a flow control valve (e.g., a check valve) <NUM>. Accordingly, when a proximal coupler <NUM> is connected to the flow control valve (as will be described further below), the proximal coupler <NUM> and the probe shaft <NUM> (in electrical communication with the proximal coupler <NUM>) are each in electrical communication with the flow control valve <NUM> and in turn with the electrically conductive housing <NUM>. The flow control valve <NUM> (best seen in <FIG> and <FIG>) and the electrically conductive housing <NUM> are each, in turn, in electrical communication with the electrically-conductive bearings <NUM>, electrically connected to the electrical contact pin <NUM>. Thus, the probe shaft <NUM> is electrically coupled to the corresponding electrical contact pin <NUM> to permit measurement of electrical signals associated therewith. In some examples, a substantial number of components of the electrical measurement system <NUM> may be electrically conductive. For instance, the entirety of the electrical contact pin <NUM>, bearings <NUM> and band-shaped spring <NUM> may be electrically conductive, and made of a material such as stainless steel, brass or other metals and alloys. Additionally, the manifold <NUM> may be electrical conductive.

As described previously, components of the cryoprobe <NUM>, such as the proximal coupler <NUM> and the probe shaft <NUM> may be electrically conductive, such that the electrical measurement system <NUM> may be electrically coupled to the probe shaft <NUM> for measuring electrical signals associated therewith. In further aspects, one or more types of electrical signals (voltage, current, resistance, and the like) can be detected by the electrical measurement system <NUM>. The control system <NUM> can use such electrical signals to detect whether the electrical heater <NUM> and the probe shaft <NUM> are electrically coupler if the signals indicate a "closed" circuit. Alternatively, if the electrical signals are indicative of an "open" circuit, the control system <NUM> determines that the electrical heater <NUM> and the probe shaft <NUM> are electrically isolated.

In an example, the electrical measurement system <NUM> can measure a voltage associated with the probe shaft <NUM>. As is appreciable, if the electric heater <NUM> does not short with the probe shaft <NUM>, the electric heater <NUM> can have a non-zero voltage (because of current supplied thereto during heating), whereas the probe shaft <NUM> may have a zero voltage. Accordingly, the control system <NUM> can determine, based on the detected electrical signals (e.g., zero voltage) associated with the probe shaft <NUM>, that it does not electrically communicate with the electric heater <NUM>. Conversely, when the electrical measurement system <NUM> detects a non-zero voltage of the probe shaft <NUM>, the control system <NUM> may determine that the electrical heater <NUM> is in electrical communication with (e.g., shorted) the probe shaft <NUM>.

In alternative embodiments, the electrical measurement system <NUM> measures resistance associated with the probe shaft <NUM>. For instance, the electrical resistance between the probe shaft <NUM> and the electrical heater <NUM> of the corresponding cryoprobe <NUM> can be measured to determine if the electrical heater <NUM> has electrical contact (e.g., shorting) with the probe shaft <NUM>. For example, a test voltage can be supplied to the electrical heater <NUM> and a current passing therethrough can be measured by the electrical measurement system <NUM>, so as to measure electrical resistance associated with the electrical heater <NUM>. In such examples, the change in electrical resistance with time can be monitored by the control system <NUM> to determine whether the temperature generated by the electrical heater <NUM> follows predetermined temperature ranges. Predetermined temperature ranges may be known, for instance, based on the material used for the electrical heater <NUM>. The control system <NUM> may then use such data to determine whether the probe shaft <NUM> and the electrical heater <NUM> are electrically isolated. Advantageously, in such embodiments, detection of electrical signals (by the electrical measurement system <NUM>) and determination of whether the electrical heater <NUM> has electrical communication with the probe shaft <NUM> (by the control system <NUM>) can be made during operation of the electrical heater <NUM> (e.g., heating, thawing, etc.) or during operation of MRI system because of electrical isolation between adjacent cryoprobes.

<FIG> illustrate respectively, a perspective view, a sectional front view and an enlarged sectional view of the connector interface <NUM> of <FIG> connected to a proximal coupler <NUM> of a cryoprobe <NUM>. In <FIG>, the electrical contact pin and bearings are hidden from view. Referring to <FIG>, when the proximal coupler <NUM> is connected to the connection port <NUM>, the isolating sleeve <NUM> is positioned between the proximal coupler <NUM> and walls <NUM> of the connection port <NUM> and substantially surrounds portions of the flow control valve, thereby electrically isolating the proximal coupler <NUM> (and in turn the probe shaft <NUM>) inserted into the connection port <NUM>. As mentioned before, several components of the connection interface and the cryoprobe <NUM> can be electrically conductive, whereas the isolating sleeve <NUM> is electrically insulating. By positioning the isolating sleeve <NUM> so as to substantially surround the flow control valve, each cryoprobe <NUM> can thereby be electrically isolated from adjacent cryoprobes and/or electrical components of the connector interface <NUM>, while being in electrical communication with components of the electrical measurement system <NUM>.

As best illustrated in <FIG> and <FIG>, each connection port <NUM> comprises a flow control valve <NUM> connectable to a corresponding proximal coupler <NUM>. The flow control valve can be a spring-loaded check valve comprising a spring-loaded connector pin <NUM>, spring-biased (e.g., by a coil spring <NUM>) to be in a "closed position (shown by solid lines). " In the closed position, the flow control valve may not permit the cryofluid to flow through its outlet <NUM>. A first spacer <NUM> generally surrounds the spring-loaded connector pin <NUM>. The flow control valve can have a fluid-tight seal by way of seals <NUM> (e.g., O-rings) positioned between the first spacer <NUM> and a second spacer <NUM>.

Continuing with <FIG>, when the proximal coupler <NUM> of the cryoprobe <NUM> is inserted into the connection port <NUM>, the proximal pin <NUM> may be pushed against the spring-loaded connector pin <NUM>, as a result of which, the insertion may exert a force to overcome the spring bias, thereby moving the flow control valve from the "closed position" to the "open position" (shown in <FIG>) so as to permit flow of cryofluid therethrough. In the illustrated embodiment of <FIG>, the spring-loaded connector pin <NUM> may move further away from the proximal pin <NUM>, and into the connection port <NUM> (shown in <FIG>) along the direction <NUM> thereby creating a gap between the planar surface <NUM> of the spring-loaded connector pin <NUM>, and the planar surface <NUM> of the first spacer <NUM>. Returning to <FIG>, the first spacer <NUM>, in turn, may have grooves or apertures to permit fluid flow therethrough (for instance, along direction <NUM>) when the spring-loaded connector pin <NUM> is moved along the direction <NUM>. When the spring-loaded connector pin <NUM> moves from the closed position (shown in <FIG>) to the open position (shown in <FIG>), cryofluid from the cryofluid supply line <NUM> can flow toward the proximal coupler <NUM> and eventually to the cryofluid supply tube of the cryoprobe.

Referring again to <FIG> and <FIG>, when the proximal coupler <NUM> is inserted into the connection port <NUM>, its proximal pin <NUM> is received within the aperture of the first spacer <NUM>. The isolating sleeve <NUM> can, at a minimum, completely electrically insulate an electrically conductive portion of the proximal coupler <NUM> and the connection port <NUM> into which that portion of the proximal coupler <NUM> is inserted. For instance, at least a tip of the proximal pin <NUM> can be electrically conductive. In such cases, the isolating sleeve <NUM> completely electrically insulates the tip (or other electrically conductive portions of the proximal pin <NUM>) and the connection port <NUM>.

Embodiments according to the present disclosure provide several advantages. Exemplary embodiments according to the present disclosure permit use of surgical tools with electrically conductive components, such as cryoprobes to be used in conjunction with MRI system. In some advantageous examples of the present disclosure, the cryoprobes can be electrically isolated from each other. Further, advantageously, in such embodiments, detection of electrical signals (by the electrical measurement system) and determination of whether the electrical heater has electrical communication with the probe shaft (by the control system) can be made during operation of the electrical heater (e.g., heating, thawing, etc.) or during operation of MRI system because of electrical isolation between adjacent cryoprobes.

Claim 1:
A cryosurgery system, comprising:
a first cryoprobe (<NUM>) and a second cryoprobe (<NUM>), the first cryoprobe and the second cryoprobe each including:
a probe shaft (<NUM>) having a distal section insertable in a patient, each probe shaft comprising an electrically-conductive material and configured to receive a cryofluid for cooling and/or freezing the patient's tissue, and a proximal coupler (<NUM>) at least a portion of the proximal coupler being electrically conductive, the proximal coupler being in electrical communication with the probe shaft;
a first connection port (<NUM>) being configured to receive and connect to the proximal coupler of the first cryoprobe;
a second connection port (<NUM>) being configured to receive and connect to the proximal coupler of the second cryoprobe; and
at least one electrical isolator (<NUM>) the first connection port and the second connection port each being fluidly connected to a cryofluid supply line (<NUM>) for receiving the cryofluid from a cryofluid source and delivering the cryofluid to the proximal coupler of the first cryoprobe and the proximal coupler of the second cryoprobe respectively;
the electrically conductive portion of the proximal coupler of the first cryoprobe being insertable into the first connection port, and the electrically conductive portion of the proximal coupler of the second cryoprobe being insertable into the second connection port;
the at least one electrical isolator being configured to electrically isolate the proximal coupler of the first cryoprobe from the proximal coupler of the second cryoprobe such that the probe shaft of the first cryoprobe is substantially electrically isolated from the probe shaft of the second cryoprobe;
the electrical isolator providing complete electrical insulation between the electrically conductive portion of at least one proximal coupler and a corresponding connection port into which the at least one proximal coupler is inserted, the corresponding connection port being the first connection port or the second connection port.