1 . A method for deploying at least one needle in tissue, said method comprising:
positioning a probe having a deployable needle proximate a surface of the tissue; providing a real time image of the tissue including both an anatomical feature to be treated and sensitive anatomic structures; overlaying the image with a projected treatment region and a projected safety boundary based on the position of the probe; repositioning the probe to align the projected treatment region and safety boundary on the real time image so that the treatment region includes at least a portion of the anatomical feature to be treated and the sensitive anatomic structure remain outside of the safety boundary; and deploying the needle from the probe after the probe has been repositioned.
2 . A method as in claim 1 , further comprising:
updating the image of the treatment region and the projected safety boundary on the image of tissue based on the actual position of the needle after the needle has been deployed; and visually confirming that the anatomical feature to be treated is within the treatment region and that the sensitive anatomic structures are outside of the safety boundary.
3 . A method as in claim 2 , wherein visually confirming comprises confirming that the needle is no closer than 0.5 cm to the sensitive anatomic structures features.
4 . A method as in claim 2 , further comprising enabling a treatment device if the sensitive anatomic structures are outside of the safety boundary.
5 . A method as in claim 4 , wherein enabling comprises responding to a prompt from the treatment device asking if the sensitive anatomic structures are outside of the safety boundary.
6 . A method as in claim 1 , wherein the probe is positioned in a uterus.
7 . A method as in claim 1 , wherein the anatomical feature to be treated includes a fibroid.
8 . A method as in claim 7 , wherein the sensitive anatomic structure to be maintained outside of the safety boundary includes a serosa.
9 . A method as in claim 1 , wherein the image is provided by a transducer on the probe.
10 . A method as in claim 1 , further comprising:
marking a location of the needle after the needle has been deployed; and updating the projected treatment region and the projected safety boundary based on the marked location on the needle.
CROSS-REFERENCE TO RELATED APPLICATION
 This application is a continuation of U.S. application Ser. No. 12/245,567 (Attorney Docket No. 31992-709.201), filed on Oct. 3, 2008, which claims the benefit of Provisional Application No. 60/979,613 (Attorney Docket No. 31992-709.101), filed on Oct. 12, 2007, the full disclosures of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates generally to medical methods and apparatus. More particularly, the present invention relates to methods and systems for controlling the deployment of needles using visual feedback from an ultrasonic or other image.
 Current medical treatments of organs and tissues within a patient's body often use a needle or other elongate body for delivery of energy, therapeutic agents or the like. Optionally the methods use ultrasound imaging to observe and identify a treatment target and the position of the needle relative to the treatment target.
 Of particular interest to the present invention, a treatment for uterine fibroids has recently been proposed which relies on the transvaginal positioning of a treatment device in the patient's uterus. A radiofrequency or other energy or therapeutic delivery needle is deployed from the device into the fibroid, and energy and/or therapeutic substances are delivered in order to ablate or treat the fibroid. To facilitate locating the fibroids and positioning the needles within the fibroids, the device includes an on-board ultrasonic imaging array with a field of view in a generally lateral direction from an axial shaft. A curved needle is advanced from the shaft and into the field of view so that the needle can be visualized and directed into the tissue and the targeted fibroid. The geometry of the needle deployment is advantageous since it permits the location and treatment of fibroids which are laterally adjacent to the shaft.
 While effective and very beneficial for patients, such needle ablation and treatment protocols face several challenges. First, initial deployment of the needle can be difficult, particularly for physicians who have less experience. While the physician can view the tissue and target anatomy in real time on an imaging screen, it can be difficult to precisely predict the path the needle will take and assess its final treatment position. While the needle can certainly be partially or fully retracted and redeployed, it would be advantageous to minimize the number of deployments required before treatment is effected.
 A second challenge comes after the needle has been deployed. While the position of the needle can be observed on the ultrasonic or other visual image, the treatment volume resulting from energy or other therapeutic delivery can be difficult to predict. As with initial positioning, experience will help but the need to exercise judgment and conjecture is best reduced.
 A third challenge is in assuring that nearby sensitive tissue structures, such as the serosa surrounding the myometrium, are not unintentionally damaged. As with judging the treatment volume, predicting the safety margin of the treatment can be difficult.
 For these reasons, it would be desirable to provide improved systems and methods for the deployment of energy delivery and other needles within ultrasonic or other imaging fields of view in energy delivery or other therapeutic protocols. It would be particularly useful to provide the treating physician with information which would assist in initial deployment of a needle in order to improve the likelihood that the needle will be properly positioned relative to a targeted anatomy to be treated. It would also be desirable, once the needle has been deployed, to provide feedback to the physician to assist in accurately predicting a treatment volume. Such information should allow the physician, if necessary, to reposition the needle in order to increase the likelihood of fully treating the anatomy. Furthermore, it would be desirable to provide feedback to the physician allowing the physician to assess a safety margin so that sensitive tissue structures are not damaged. All such feedback other information are preferably provided visually on the ultrasonic or other imaging screen so that the needle position can be quickly predicted, assessed, and treatment initiated. At least some of these objectives will be met by the inventions described hereinafter.
 2. Description of the Background Art
 U.S. Patent Publication No. 2006/0189972, published on Aug. 24, 2006 and commonly assigned with the present application, describes probes useful for both imaging and treating uterine fibroids, which probes could be used in the systems and methods of the present application. Other commonly assigned applications describing probes useful for treating uterine fibroids in the systems and methods of the present invention include application Ser. No. 11/409,496 (Attorney Docket No. 025676-000700US), filed on Apr. 20, 2006; Ser. No. 11/564,164 (Attorney Docket No. 025676-000710US), filed on Nov. 20, 2006; Ser. No. 11/620,594 (Attorney Docket No. 025676-000310US), filed on Jan. 5, 2007; and copending provisional application No. 60/938,140 (Attorney Docket No. 025676-001700US), filed on May 15, 2007, the full disclosures of which are incorporated herein by reference. Other related, commonly assigned applications are Ser. No. 11/620,569 (Attorney Docket No. 025676-000420US), filed Jan. 5, 2007; and Ser. No. 11/775,452 (Attorney Docket No. 025676-001010US), filed on Jul. 10, 2007. The full disclosures of each of these commonly owned, pending applications are incorporated herein by reference.
BRIEF SUMMARY OF THE INVENTION
 The present invention provides both methods and systems for deploying one or more needles in tissue. The needles are usually intended to deliver a therapy to the tissue, most typically being adapted to deliver radiofrequency, plasma, heat, or other energy to ablate or otherwise modify the tissue or a targeted anatomy within the tissue. In other embodiments of the present invention, however, particularly those relating to initial needle deployment, the needles could also be intended for biopsy or have other diagnostic purposes.
 One or more needles are deployed in tissue where the tissue is being imaged so that at least a portion of the needle (once deployed) and at least one anatomical feature within the tissue will be visible, preferably on a display screen in real time before, after, and/or during needle deployment. In a first specific aspect of the present invention, the image is overlaid with projected needle treatment information. By “projected,” it is meant that the needle treatment information is predicted or calculated based on known or determined system information. For example, the shape of the needle and mechanics of the needle deployment system may be used to predict the path that the needle may take into tissue, as described in greater detail below. The treatment volume and safety boundaries or margins may be calculated or predicted based on the energy delivery characteristics of the system together with the anticipated tissue characteristics. The information overlaid on the image will allow a user, typically a treating physician, to evaluate the predicted and/or actual needle positions relative to both treatment efficacy and safety.
 In the exemplary embodiments, at least one needle will be deployed from a probe where the probe may be introduced to the uterus or other body cavity or lumen. Exemplary anatomical features that may be imaged and subsequently treated or biopsied include fibroids, tumors, encapsulated tissue masses, pseudoencapsulated tissue masses, and the like. Of particular interest to the present invention, the probe may be positioned in the uterus and the needle deployed to a location proximate or into a fibroid located in the myometrium surrounding the uterus. In such cases, it will usually be desirable to also image the serosa which surrounds the myometrium and/or other sensitive anatomical features that could be damaged by the energy-mediated or other therapeutic treatment.
 Thus, in a first specific aspect of the present invention, the projected needle information will include at least a projected safety boundary which provides a visual image of the treatment volume that can be provided through the needle. In such cases, evaluating can comprise confirming that the serosa or other sensitive tissue or anatomical structure is outside of the projected safety boundary (where tissue within the projected safety boundary is at risk of tissue damage). The projected safety boundary will usually provide a minimum distance between the needle and the serosa or other sensitive anatomical feature which is at least 0.5 cm, often being at least 0.7 cm, and preferably being at least 1 cm.
 In a second specific aspect of the present invention, the projected needle treatment information will comprise a projected needle deployment path. The projected needle deployment path will typically find use prior to needle deployment where the treating physician can manipulate the probe which carries the needle so that the projected needle treatment path visible on the display screen is aligned so that the needle will enter or at least be reasonably close to the targeted anatomy to be treated. The projected needle treatment information will be based on the known mechanical characteristics of the needle and may vary for different needles. In some instances, it will be desirable to actually test individual needles which are being used so that their individual characteristics are known, but this will usually not be necessary. It will be appreciated that the actual needle entry path, while predictable within certain tolerances, may differ from the projected path due to differences in the tissue characteristics, small differences in the deployment mechanisms, differences in the needle characteristics, or other reasons. In such instances, the methods and systems of the present invention will allow for inputting the actual treatment position so that the safety and treatment boundaries can be predicted based on the actual needle position, not the predicted needle position. For example, the physician may locate a known point or artifact on the needle which appears in the visual image. By then “clicking on” that point or otherwise feeding that positional information back into the imaging and control system, the system can recalculate the actual needle position and, based on the actual position, calculate the safety and treatment boundaries.
 In a third specific aspect of the present invention, the projected needle treatment information comprises a projected therapy region. The projected therapy region will be a boundary or volume which is shown on the visual display to allow the treating physician to assess whether the target region to be treated will likely be effectively treated based on the needle position. As just discussed, usually the projected needle treatment information is preferably based on the actual needle position but could also be based on the projected needle position. Thus, it may be possible for the treating physician to rely on a projected therapy region (as well as a projected safety boundary) while the projected needle position is being manipulated relative to the targeted anatomy to be treated. After actual deployment, the system can recalculate both the projected therapy region and the projected safety boundary to allow the treating physician to confirm both that the treatment will likely be effective and that the serosa and/or other sensitive tissue structures will not be damaged.
 In a further specific aspect of the present invention, the treatment system will provide for an interlock or enablement step before treatment can be delivered to the tissue. For example, the system may require the treating physician to acknowledge that either or both of the safety boundary and treatment volumes have been observed and evaluated to determine that the treatment will be safe and/or effective. Without such acknowledgement, the system could preclude energy delivery until such time as the treating physician acknowledges evaluation of the safety and/or effectiveness. In other instances, the system could be modified to assess the projected boundaries relative to the targeted treatment anatomies and the sensitive tissue anatomy, although such fully automated systems are not presently preferred.
 The methods of the present invention will preferably employ the uterine fibroid treatment probes, such as those described in the commonly owned, copending applications incorporated herein by reference above. These treatment probes comprise a shaft having both an imaging transducer and a deployable needle near the distal end. The needle is configured so that it may be selectively advanced in a generally lateral direction within the field of image of the transducer, typically an ultrasonic imaging array. After the needle has been advanced into the tissue, and the safety and effectiveness of the needle position have been confirmed, therapy may be administered through the needle, such as radiofrequency tissue treatment or other energy or non-energy mediated treatments. Exemplary energy treatment modalities include radiofrequency, microwave, high intensity focused ultrasound (HIFU), liquid infusion, plasma infusion, vapor, cryotherapy, and the like.
 In another embodiment of the present invention, a needle is deployed in tissue by first positioning a probe having a deployable needle proximate a surface of the tissue. An image of the tissue is provided in real time, and a projected needle path is overlaid on the image. Prior to actually deploying the needle, the probe is repositioned to align the projected needle path on the real time image with anatomical feature. After the probe has been repositioned to optimize the position of the projected needle path within the anatomical feature, the needle may be deployed from the probe. After the needle has been actually deployed, the actual needle position may be fed back into the imaging system by marking a location on an image of the needle. Based on the actual needle position provided by the marked location, the projected safety boundary may be calculated by the system and overlaid on the image. Based on the projected safety boundary, the physician may visually confirm that sensitive anatomic structures are safe. Usually, the tissue image will also be overlaid with a projected treatment boundary based on the marked location. The physician may then also visually confirm that at least a portion of the anatomical feature to be treated is within the projected treatment boundary. The system may also be programmed so that the treatment device will be enabled only if the sensitive anatomic structures are outside of the safety boundary, typically by requiring the treating physician to acknowledge that the anatomical structures are safe.
 Systems for deploying needles in tissue in accordance with the principles of the present invention comprise a probe and a system controller. The probe includes one or more deployable needles and an imaging transducer, where the needle(s) is (are) configured to be advanced into an image field produced by the imaging transducer. The system controller includes a screen for displaying the image produced by the transducer, where the system controller provides for an overlay on the screen with projected needle treatment information. The projected needle treatment information may comprise a projected needle path, where the physician can manipulate the probe to align the projected needle path with a target anatomy in the image field visible on the screen. The needle information may further comprise a projected treatment boundary and/or projected safety boundary. In such instances, the system may require the physician to confirm that the projected or actual needle position is safe and/or effective prior to enabling a therapy. Usually, the system will be able to update the projected needle information based on the actual needle position. In exemplary systems, the system controller further includes a generator for producing a therapy to be delivered through the needle, such as a radiofrequency, microwave, high intensity focused ultrasound (HIFU), vapor, liquid infusion, and cryotherapy. Systems may employ needle arrays comprising multiple needles.
 Methods for treating fibroids and other anatomical features further comprise deploying at least one needle in the uterus proximate, usually within, the anatomical feature. The methods may deploy multiple needles in needle arrays. Radiofrequency energy is delivered into the feature through an exposed portion or portions of the needle, where no exposed needle portion is closer than 0.5 cm to the serosa, usually being no closer than 0.7 cm, and preferably being no closer than 1 cm. such methods can achieve effecting treatment of many or most fibroids or other features without damaging the serosa.
BRIEF DESCRIPTION OF THE DRAWINGS
 FIG. 1 is a schematic illustration of the system comprising a system controller and a needle treatment probe constructed in accordance with the principles of the present invention.
 FIGS. 2 through 4 illustrate an exemplary needle treatment probe which may be used in the methods and systems of the present invention for the treatment of uterine fibroids.
 FIG. 5 is a flowchart illustrating an exemplary treatment protocol in accordance with the principles of the present invention.
 FIGS. 6A and 6B illustrate use of the needle treatment probe of FIGS. 2 through 4 in the treatment of a uterine fibroid in accordance with the principles of the present invention.
 FIG. 7 illustrates exemplary dimensions for a treatment region and a safety boundary for the needle deployment probe of FIGS. 2 through 4 .
 FIGS. 8A through 8G illustrate exemplary images which might be viewed by a treating physician when deploying the needle deployment probe of FIGS. 2 through 4 in treating a uterine fibroid generally as shown in FIGS. 6A and 6B .
DETAILED DESCRIPTION OF THE INVENTION
 As illustrated in FIG. 1 , a system 10 constructed in accordance with the principles of the present invention includes both a system controller 12 and treatment probe 14 . The system controller 12 will include a processing and power unit 16 and a display screen 18 . The controller 12 will further include means for the treating physician to input information, such as a keyboard, touch screen, control panel, or the like. The processing and power unit 16 will usually include a radiofrequency, microwave, vapor, treatment plasma, or other circuitry or mechanisms for delivering the treatment energy or other treatment agents to the treatment probe 14 . Conveniently, the system controller 12 could comprise a conventional desktop or laptop computer to provide both the screen and logic and be connected to a separate radiofrequency, microwave, HIFU, liquid infusion, plasma infusion, vapor, cryotherapy or other source to provide the desired treatment.
 The treatment probe 14 typically includes a shaft 20 having a handle 22 at its proximal end. A needle 24 and imaging array 26 are provided at the distal end of the shaft 20 , as described in more detail with reference to FIGS. 2 through 4 . The treatment probe 14 shown in FIGS. 2 through 4 is described in more detail in copending provisional application No. 60/938,140 (Attorney Docket No. 025676-001700US), filed on May 15, 2007, the full disclosure of which has previously been incorporated herein by reference.
 The probe 14 generally includes a rigid or other delivery shaft 20 , an ultrasound imaging transducer 26 , and an echogenic curved needle 24 with an artifact/feature 100 at a distal end 51 ( FIG. 3 ) thereof. As shown, the artifact is a corner cut type retroreflector. The handle 22 is attached to a proximal end 21 of the shaft 20 . A distal end 23 of the shaft 20 has a bent or deflectable distal tip, as best seen in FIG. 4 . The ultrasound imaging transducer 26 comprises a linear ultrasound array disposed in a flat viewing window 36 ( FIG. 3 ) which images in a field of view 46 ( FIG. 4 ). Although only a single straight needle 24 is illustrated, the probe may carry multiple needles in arrays and/or the needles may be straight or have any other configuration.
 The needle 24 is a solid tip electrically conductive needle intended for radiofrequency tissue ablation. As discussed elsewhere, it could also be intended for delivery of other forms of energy or be a hollow core needle intended for substance delivery or injection. The exemplary needle 24 generally comprises a two-piece construction including an elongate hollow body 48 (as best seen in FIG. 3 ) and a solid distal tip 50 at a distal end thereof. The distal tip 50 may be laser welded to the hollow tubular body 48 . The solid tip 50 may also be attached via alternative means, for example adhesives or mechanical features or fits. The hollow tube 48 will generally have a length in a range from about 20 cm to about 45 cm. In some embodiments, the hollow tube will have an oval cross section having a thickness generally in a range from about 0.5 mm to about 2 mm and a wideness generally in a range from about 1 mm to about 3 mm. This flattened oval cross sectional shape, when present, is intended to inhibit lateral deflection during deployment or penetration of the needle 24 . FIG. 3 also illustrates a representative laser cut hole 60 within the distal end of the tubular body 48 for the infusion of agents (e.g., electrolytes, drugs, etc.) so as to enhance the therapeutic effect of the needle 14 prior to or during ablation treatment. The infusion hole 60 may be aligned on one side of the tubular body 48 and generally has length in a range from about 0.5 mm to about 2 mm and a width in a range from about 0.5 mm to about 2 mm. It should be noted that hole 60 may comprise one or a plurality of holes, and each may be used for a different purpose.
 The handle 24 further includes a longitudinally movable slider 72 for enabling the advancement and retraction of the needle 14 to and from within a needle guide 44 . The ultrasound imaging transducer 26 may optionally be present on an imaging insert replaceably disposed within the axial passage of the shaft 20 . A sealing element 30 may be provided between the ultrasound imaging transducer 26 and the shaft handle 24 to ensure sufficient sealing around the insert at a proximal end. It will be appreciated that the above depictions are for illustrative purposes only and do not necessarily reflect the actual shape, size, or dimensions of the system 10 . Furthermore, the ultrasound array may be parallel to an axis of the shaft 20 or may be slightly inclined as illustrated in FIG. 4 . This applies to all depictions hereinafter. The array is typically a linear array with from 16 to 128 elements, usually having 64 elements. The length (azimuth) of array 12 usually ranges from about 5 mm to about 20 mm, normally being about 14 mm. The array may have a depth (elevation) ranging from about 1 mm to about 8 mm, normally being about 2 mm. In an embodiment, the ultrasound array transmits ultrasound waves at a center frequency ranging from about 2 MHz to about 15 MHz, typically from about 5 MHz to about 12 MHz, normally about 6.5 MHz.
 Referring now to FIG. 5 , an exemplary protocol for performing the needle positioning methods of the present invention for treating uterine fibroids will be described. After the probe 14 is positioned in the uterus, the treating physician scans the myometrium M in order to locate fibroids F, as shown in FIG. 6A . Shaft 20 is manipulated so that the field of view 46 of the transducer array 26 provides a visual image, such as that shown in FIG. 8A , on the screen 18 of the system 12 . Once a fibroid F is located, the physician can scan the image for other anatomical features such as the treatment-sensitive serosa S, as also shown in FIG. 8A . It should be appreciated that the image being produced is “real time,” and that the image will change as the physician moves the shaft 20 within the uterus U so that the field of view 46 scans over different portions of the myometrium.
 The next step in the protocol of FIG. 5 relies on aligning a needle guide overlay with the fibroid. The needle guide may be a simple pair of parallel lines 70 , as shown in FIG. 8B . The parallel lines 70 will typically represent the limits of the most likely lateral needle advancement path. Thus, by aligning the lines 70 generally across the target fibroid F, as shown in FIG. 8C , the likelihood that the needle will be directed into the middle of the fibroid is increased.
 The treating physician continues to visually assess the position of the needle guidelines 70 relative to the fibroid F until they are acceptably aligned, as shown in FIG. 8C . The physician then advances the actual needle into the tissue as shown in FIG. 6B , where the image of the actual needle is shown in FIG. 8D . After the image of the actual position of the needle appears, the physician marks a preselected position on the needle, either by moving a curser on the image and clicking, touching the screen, or the like. Such “marking” of the actual position allows the system to calculate or recalculate a projected safety boundary and a projected therapy region. For example, the system may be marked near the tip of the needle, as shown at location 80 on FIG. 8E .
 Referring now to FIG. 7 , an exemplary safety boundary 90 and treatment region 92 for a single needle fibroid ablation system will be described. A treatment needle 24 has an uninsulated treatment portion 96 having a length 1 in the range from 1 cm to 3 cm, typically being 2 cm. The safety boundary will be an oval line which is generally a distance s from the exposed exterior of the treating electrode portion 96 . The distance s is usually in the range from 1 cm to 3 cm, typically being about 1.5 cm. A distance t between the exposed needle portion 96 and the treatment region boundary 92 will typically be about half that of the safety distance s, typically being in the range from 0.5 cm to 1.5 cm, usually being about 0.75 cm. Generally, the distance tt from the distal tip of the needle 24 and the safety boundary and the treatment region perimeter will be somewhat less because of the reduced energy density at the tip. Thus, the distance tt between the tip and the treatment region perimeter may be from 0.1 cm to 0.5 cm, usually being about 0.25 cm while the distance is between the tip and the safety boundary will be in the range from 0.5 cm to 1.5 cm, typically being about 1 cm.
 Based on these desired clearance distances, the system projects treatment and safety overlays on the actual image of the needle 24 , as shown in FIG. 8F . The physician can then visually assess whether sensitive tissue structures, such as the serosa S remain outside of the projected safety boundary 90 . As shown in FIG. 8F , the serosa S is inside of the safety boundary 90 , so it will be necessary to reposition or redeploy the needle 24 to move the serosa S beyond the safety boundary. It is noted that the position of the treatment perimeter 92 about the fibroid F is probably sufficient for treatment, but the needle needs to be deployed based on safety concerns.
 Once the needle has been repositioned or redeployed so that the treatment region 92 sufficiently covers the fibroid F while the safety boundary does not encroach upon the serosa S as shown in FIG. 8G , the physician will enable the system for treatment. Usually, the system will require the physician to acknowledge that the needle has been properly positioned before allowing the system to power the needle. Once that is done, the physician can initiate treatment, as described generally in the prior applications which have been incorporated herein by reference.
 While the above is a complete description of the preferred embodiments of the invention, various alternatives, modifications, and equivalents may be used. Therefore, the above description should not be taken as limiting the scope of the invention which is defined by the appended claims.