Abstract: This document discusses, among other things, fiducial marker devices, tools, and methods. One example illustrates a combined imagable fiducial locator and divot for receiving a positioning wand of an image-guided surgical (IGS) workstation. A further example is reflective such that it is locatable by a remote detector of an optical positioning system. A generally cylindrical (e.g., faceted cylindrical) columnar locator permits easy application of reflective tape. Other examples discusses a unitary fiducial marker with multiple divots and a swiveling and/or tilted fiducial marker divot, each of which allows manipulation of a positioning wand into a remote camera's field of view. Another example includes at least one reflector that can be aimed. A further example discusses an imagable fiducial marker carrier that is attachable to a single location on a patient's skull to reduce trauma.

Abstract: A marker comprising a hollow body filled with a magnetic resonance imaging medium is used to mark specific surface areas of concern or sources of pain on a patient's skin prior to commencing MRI imaging procedures. The hollow body is sized such that the marker appears on less than five MRI slice images, and preferably not more than two MRI slice images, thereby enabling a physician or technician to precisely locate and assess a patient's condition based on the location of the marker in the MRI images.

Abstract: A method of imaging a body part includes locating a first, second and third anatomical reference area. The third anatomical reference area is disposed generally between the first and second anatomical reference areas. Furthermore, the method includes positioning a first member of a reference tool relative to the first anatomical reference area, positioning a second member of the reference tool relative to the second anatomical reference area, and a pivotal coupling member relative to the third anatomical reference area. The pivotal coupling member pivotally couples the first and second members of the reference tool. In addition, the method includes imaging a target area of the body part to produce an image. The image includes the target area of the body part and the first and second members. The first member indicates a first axis of the body part, and the second member indicates a second axis of the body part.

Abstract: A shape of a medical device to be implanted into a subject is verified by acquiring a plurality of inter-fiduciary marker dimensions from the subject. Three-dimensional image data of the markers and a tissue of interest, included in the subject, is obtained. Respective measurements between the fiduciary markers around the subject and in the image data are confirmed. The tissue of interest and the fiduciary markers are identified in the image data. Points of the tissue of interest and the fiduciary markers are rendered as a 3-dimensional surface representation. A 3-dimensional model of the tissue of interest and the fiduciary markers is generated as a function of the surface representation. A shape of the medical device to be implanted into the subject is determined as a function of the 3-dimensional model.

Abstract: An implantable tissue marker incorporates a contrast agent sealed within a chamber in a container formed from a solid material. The contrast agent is selected to produce a change, such as an increase, in signal intensity under magnetic resonance imaging (MRI). An additional contrast agent may also be sealed within the chamber to provide visibility under another imaging modality, such as computed tomographic (CT) imaging or ultrasound imaging.

Abstract: A method of preplanning for guided medical procedures includes obtaining a first 3D diagnostic dataset for a region of interest of a subject. This first dataset can be a non-stereotactic dataset and provide sufficient contrast to identify target tissue in the region of interest. A treatment preplan is developed to treat the target tissue using the first dataset exclusive of stereotactic data. The treatment preplan includes placement locations for a plurality of initial radiation beams and their respective dose intensities. A second, stereotactic 3D dataset can be obtained for the region of interest. A registered dataset can then be created by registering the first dataset to the second dataset. The treatment preplan can be modified using data associated with the registering step to generate a stereotactic treatment plan including a plurality of radiation treatment beams with respective placement positions based on the registered dataset to treat the target tissue.

Abstract: A medical device includes a sensor for sensing for an MRI gradient magnetic field and a microprocessor for responding to the detected gradient magnetic field by switching from a first electrical signal processing mode to a second electrical signal processing mode, such that electrical signals induced by the gradient magnetic field and an associated RF burst are not counted as cardiac events.

Abstract: A method for determining an item of positioning information for ECG electrodes during an examination with a magnetic resonance facility is provided. An image data record of a region surrounding the heart of a patient and the electrodes arranged on the surface of the patient is recorded. A position of the longitudinal heart axis and a position of the electrodes in the image data record are determined. A target position suited to determining evaluable ECG signals is automatically calculated for each of the electrodes by considering the position of the longitudinal heart axis and a displacement from the position of the electrodes to the target position. An item of positioning information for the electrodes is displayed by taking the displacements into consideration. A clean copy of the abstract that incorporates the above amendments is provided herewith on a separate page.

Abstract: A device, system, and method for entering a medical device such as a needle into the body inside a medical imager such as a MRI scanner, CT, X-ray fluoroscopy, and ultrasound imaging, from within a body cavity (such as the rectum, vagina, or laparoscopically accessed cavity). A three degree-of-freedom mechanical device translates and rotates inside the cavity and enters a needle into the body, and steers the needle to a target point selected by the user. The device is guided by real-time images from the medical imager. Networked computers process the medical images and enable the clinician to control the motion of the mechanical device that is operated within the imager, outside of the imager or remotely from outside the imager.

Abstract: An apparatus and method for magnetic resonance scanning is described. The apparatus comprises an RF coil (16) for receiving an RF signal, a housing (10) for housing the RF coil, and a support (38). The support (38) is provided for locating a fiducial marker (50) in a repeatable position relative to the housing (10), the repeatable position being within the RF field of the RF coil (16). The fiducial marker, in use, provides a reference peak in a magnetic resonance spectroscopy spectrum. Methods of using such apparatus for magnetic resonance scanning, are also outlined. In particular a method is described that includes the step of providing a housing (10) that comprises a recess (38) located within the RF field of the RF coil (16). A fiducial marker (50) is then placed in the recess without exposing the RF coil (16).

Abstract: These are biopsy site marking devices. More particularly, the devices include a body of gelatin and an x-ray detectable body of a specific, predetermined non-biological configuration embedded in the body of gelatin. In one embodiment, the x-ray detectable body is made from metal. In alternative embodiments, the x-ray detectable body can be made from stainless steel or metal oxides.

Abstract: A method for use during a procedure on a body. The method generates a display representing relative positions of two structures during the procedure.

Abstract: A positioning device is applied in a reproducible manner to a patient, allows indication of the position of an anatomical area of the patient, allows the patient to be positioned in a reproducible manner in relation to an examination area of a medical examination device and a therapy area of a therapy device, and includes an antenna arrangement for the examination with a magnetic resonance device. In one embodiment, the positioning device also includes an arrangement for immobilizing the patient.

Abstract: A magnetic resonance imaging apparatus includes an RF coil unit which generates RF pulses toward a subject, and which receives an MR signal from the subject. Gradient magnetic field coils generate a gradient magnetic field for slice selection, a gradient magnetic field for phase encoding and a gradient magnetic field for frequency encoding, respectively. An arithmetic unit generates image data on the basis of the MR signal, and a sequence controller controls phase encoding gradient magnetic field coils in order to generate flow pulses for dephasing or rephasing the MR spin of blood flow within the subject, in the same direction as that of the phase encoding gradient magnetic field.

Abstract: A method of performing a surgery is provided including a surgical navigation system having a tracking system, computer and monitor placed outside of a sterile field. An input pad and a tracking array attachable to a surgical instrument or bone are placed into the sterile field along with a probe having a probe array. The tracking array and the probe array are acquired by the tracking system and a virtual mouse is activated by positioning the probe relative to the input pad, thereby causing a mouse input to the computer with the virtual mouse.

Abstract: This document discusses, among other things, fiducial marker devices, tools, and methods. One example illustrates a combined computed tomography (CT) imagable fiducial locator head, an integral bone screw, and an integral divot for receiving a positioning wand of an image-guided surgical (IGS) workstation. A further example includes a fluid/gel-absorbing coating or cover into which a magnetic resonance (MR) imagable fluid is introduced, thereby permitting both CT and MR imaging. Protective caps and collars may be used to protect the fiducial marker from mechanical impact and/or to guide the fiducial marker during affixation. A bull's-eye or other template is used to select a center of a substantially spherical fiducial marker head on an image, such as for use during patient registration.

Abstract: Digital x-ray images taken before a surgical procedure by a fluoroscopic C-arm imager are displayed by a computer and overlaid with graphical representations of instruments being used in the operating room. The graphical representations are updated in real-time to correspond to movement of the instruments in the operating room. A number of different techniques are described that aid the physician in planning and carrying out the surgical procedure.

Abstract: A marking tool for use in the context of radiological and other medical imaging is disclosed. The product is a marking tool for distributing an imaging material onto a patient's skin to mark that part of the patient's body for imaging. The imaging technician then knows the area of medical interest, such as an internal injury, and can image that area more accurately. The imaging material shows up on a resulting medical image such as an X-Ray, CT Scan, or MRI to direct a radiology professional to the most important area on the image for diagnostic purposes.

Abstract: An objective viewpoint image of an object captured at an objective viewpoint position is obtained, a measurement value of a sensor is received, information about the image coordinates of calibrating indices is detected from an objective viewpoint image, and two kinds of arrangement information of the calibrating indices and the sensor both placed on and relative to the object are obtained on the basis of the measurement value and the information about the image coordinates of the calibrating indices. With this, the two kinds of arrangement information are easily and accurately obtained at the same time.

Abstract: The invention relates to a method for registering an image data set for visualizing internal areas of the body. The method can include determining the relative position of an imaging device and of an external body part associated with an internal area of the body and producing an image data set for the internal area of the body by means of the imaging device. The spatial position of the external body part is determined and the image data of the internal area of the body are registered or assigned according to relative position, with respect to the spatial position of the external body part, on the basis of the relative positional information.

Abstract: The invention is directed biopsy site markers and methods of marking a biopsy site, so that the location of the biopsy cavity is readily visible by conventional imaging methods, particularly by ultrasonic imaging. The biopsy site markers of the invention have high ultrasound reflectivity, presenting a substantial acoustic signature from a small marker, so as to avoid obscuring diagnostic tissue features in subsequent imaging studies, and can be readily distinguished from biological features. The several disclosed embodiments of the biopsy site marker of the invention have a high contrast of acoustic impedance as placed in a tissue site, so as to efficiently reflect and scatter ultrasonic energy, and preferably include gas-filled internal pores. The markers may have a non-uniform surface contour to enhance the acoustic signature. The markers have a characteristic form which is recognizably artificial during medical imaging.

Abstract: An MRI-compatible patch for identifying a location includes a flexible base layer, a flexible substrate and at least one of MRI-visible fiducial element. The flexible base layer is mountable on and substantially conformable to a patient's body surface. The base layer has opposed upper and lower primary surfaces. The flexible substrate is releasably attached to the upper primary surface of the base layer and substantially conformable to the patient's body surface. The at least one MRI-visible fiducial element is defined by or secured to the flexible substrate. The patch may include a plurality of the MRI-visible fiducial elements arranged in a defined pattern.

Abstract: Techniques for detecting fluorescence emitted by molecular constituents in a wall of a body lumen include introducing an autonomous solid support into the body lumen. Cells in a lumen wall of the body lumen are illuminated by a light source mounted to the solid support with a wavelength that excites a particular fluorescent signal. A detector mounted to the solid support detects whether illuminated cells emit the particular fluorescent signal. If the particular fluorescent signal is detected from the illuminated cells, then intensity or position in the lumen wall of the detected fluorescent signal, or both, is determined. These techniques allow the information collected by the capsule to support diagnosis and therapy of GI cancer and other intestinal pathologies and syndromes. For example, these techniques allow diagnostic imaging using endogenous and exogenous fluoroprobes, treating diseased sites by targeted release of drug with or without photoactivation, and determining therapeutic efficacy.

Abstract: The invention relates to a method for supporting an examination by means of an imaging diagnostic device. An examination mode is first selected by a user. At least one partial view of an examination object is subsequently generated and compared with a stored standard view, on which at least one accessory required for the examination mode is displayed. The comparison checks whether the at least one accessory is present on the partial view of the examination object. The result of the comparison is indicated to the user to ensure that the necessary accessories are present at a beginning of an actual examination even with a plurality of possible measuring methods.

Abstract: A system and method for MR imaging includes a magnetic resonance imaging (MRI) system having a plurality of gradient coils positioned about a bore of a magnet, and an RF transceiver system and an RF switch controlled by a pulse module to transmit RF signals to an RF coil assembly to acquire MR images. The apparatus further includes a controller programmed to determine a variable flip angle (VFA) sequence to excite a hyperpolarized material in a subject and to determine a delay period during which application of the VFA sequence is delayed after injection of a hyperpolarized contrast agent. The delay period is based on dynamic data of the hyperpolarized material acquired from the subject. The controller is also programmed to cause application of the VFA sequence to excite the hyperpolarized material in the subject and to acquire MR data from the hyperpolarized material using an isotropic centric phase encoding (iCPE) technique.

Abstract: A method for registration of cardiac image data in an interventional system includes inserting a first plurality of fiducial points on an acquired 3D anatomical image and exporting the 3D anatomical image, with the first plurality of inserted fiducial points thereon, to an interventional system. A second plurality of fiducial points is inserted on the exported 3D anatomical image using the interventional system, and the first and said second plurality of fiducial points are aligned to one another so as to register the exported 3D anatomical image with the interventional system.

Abstract: The invention relates to a method, system and computer software product for detecting a fiducial in digital projection images, particularly for detecting a fiducial in digital X-ray images automatically, without any operations required of the user. The invention for detecting the image of a fiducial positioned in a digital projection image is characterized in that for at least part of the digital projection image pixels, there is calculated a direction of the intensity gradient; there is defined a region of the projection image, on the basis of the directions of the intensity gradients, where the direction of the intensity gradient is changed according to predetermined limits; and there is defined a matching rate for how well the model describing the image of the predetermined fiducial matches the defined region.

Abstract: Methods and apparatuses for providing a reference array input device for use with a computer-aided surgical navigation system. A reference array input device according to an embodiment of the present invention is configured to provide a plurality of fiducial members comprising portions capable of being sensed by at least two sensors associated with the computer-aided surgical navigation system in order to determine position and orientation of the reference array input device by the system. The reference array input device can include a plurality of indicator detectors adapted to facilitate selection of a corresponding instruction associated with the computer-aided surgical navigation system. The reference array input device can also include a mount adapted to support the reference array input device adjacent to an object, a surgical instrument, or a joint replacement prosthesis.

Abstract: A first method for medically imaging a patient includes obtaining a carrier medium containing fluorescent nanoparticles. The carrier medium containing the fluorescent nanoparticles is disposed inside the patient at a site where the carrier medium will migrate to specific tissue of known shape. The nanoparticles are activated to fluoresce. Image data of the patient is obtained including the specific tissue after the specific tissue has picked-up the fluorescing fluorescent nanoparticles. The known shape of the specific tissue is identified in the image data. An image representation of the image data is created using the identified known shape as a fiducial. An image of the image representation of the image data is displayed. In a second method, the carrier medium is injected inside tissue of the patient at a site where the carrier medium will be localized in the injected tissue, and the injecting deposits the medium in a predetermined shape in the tissue.

Abstract: The present invention discloses neurochemical agents and biochemical agents for human or mammalian neuro- and body-metabolic imaging, comprising chemicals involved in neuronal or glial function, neuromodulatory processes in the brain of said human or mammalian, vascular function, or organ specific metabolic processes; said neurochemical and biochemical agents are labeled with stable isotopes selected from a group including carbon-13, nitrogen-15, deuterium, fluorine-19 or a combination thereof in predetermined positions, so as to enhance the detectability of the agents and their metabolic successors.

Abstract: Brain Magnetic Resonance Imaging (MRI), Computerized Tomotography (CT), or other diagnostic modalities may employ a three-step procedure during initial (“scout”) cranial pre-scans that corrects for patient positioning (i.e., roll, yaw and pitch) to reduce inter- and intra-patient variation, thereby enhancing the diagnostic and comparative value of subsequent detail scans even across different diagnostic platforms. In MRI, for instance, locating the saggital sinus (SS) and optimizing a line to bisect the brain through this SS may be automated to correct for roll and yaw. By then identifying the contour of the corpus callosum in a lateral saggital scout scan, the Talairach anterior commissure (AC)—posterior commissure (PC) reference line may be found for correcting pitch. Prescription of detailed scans are improved, especially when the three-step correction is repeated periodically identifying the need to repeat a detailed scan or to adjust the coordinates of a subsequent scan.

Abstract: A fiducial marker assembly (30) is tracked using a magnetic resonance scanner (10). At the tracked position of the fiducial marker assembly, local B0 magnetic field inhomogeneity is measured. A warning is issued if the measured local B0 magnetic field inhomogeneity satisfies a warning criterion. A noise figure of merit of the tracking is also determined, and the warning is also issued if the noise figure of merit satisfies a noise-based warning criterion.

Abstract: In a method and an apparatus for transforming the coordinate system of MRI-guided medical equipment to the coordinate system of an MRI system MRI imaging is used to determine the rotational and translational values of the coordinate system of MRI-guided medical equipment relative to the coordinate system of an MRI system, so as to achieve the transformation. A number of fiducial markers are arranged in the MRI-guided medical equipment, and a coil winding is arranged on each fiducial marker for generating signals to determine its position in the coordinate system of the MRI system. The coil windings are serially connected and the serially connected windings are connected to the magnetic resonance system via an interface circuit.

Abstract: A delivery apparatus for the percutaneous placement of a medical device at an area of interest in a tissue mass comprises an introducer comprising a cannula having an insertion tip, an expulsion opening near the insertion tip, and a medical device within the cannula comprising an imaging element, and a guide element connected to the imaging element and having a separable portion, and wherein the cannula is inserted into the tissue mass such that the medical device can be expelled through the expulsion opening into the tissue mass, and when the cannula is withdrawn from the tissue mass, the imaging element is placed within the tissue mass at the area of interest, and at least part of the guide element extends exteriorly of the tissue mass, and when the separable portion is separated from the guide element, no part of the guide element extends exteriorly of the tissue mass.

Abstract: A medical guide (1, 15) is provided for guiding a medical instrument into a target site within a patient's body, for use in connection with a cross-sectional imaging technique such as magnetic resonance imaging or computed tomography. The medical guide comprises a base (2, 16) adapted to be positioned on the patient's body, a trajectory guide (5, 17) movably connected to the base, wherein the trajectory guide is provided with at least one distal marker (7, 22) and at least one proximal marker (8, 23) visible by said cross-sectional imaging technique, and the markers are separated by at least one portion not visible in a chosen cross-sectional imaging technique. Furthermore, the alignment markers are placed so as to optimize the trajectory path and facilitate the procedure of e.g. taking a biopsy sample using the selected cross-sectional imaging technique.

Abstract: A multi-mode medical device system and method of using same to perform an interventional procedure. The multi-mode medical device system includes a medical device and an electrical circuit coupled to the medical device. The electrical circuit includes an integrated tracking device (e.g., a solenoid) and an imaging/visualizing device (e.g., a resonant loop). The multi-mode medical device system also includes a thermal ablation device coupled to the medical device and to the tracking device.

Abstract: A mounting bracket for use with a reference array of a computer assisted surgery system includes a base and an arcuate support frame coupled to the base. The base is configured to be secured to a bone of a patient. The arcuate support frame includes a plurality of mounts. Each mount is configured to receive a mounting end of the reference array. In some embodiments, the arcuate support frame may be pivotable with respect to the base. Additionally, in some embodiments, the arcuate support frame may be movable about an arc defined by the arcuate support frame.

Abstract: Certain embodiments of the present invention provide methods and systems for imaging system calibration using a field replaceable unit. Certain embodiments provide a field replaceable unit for imaging system calibration. The unit includes an array of radio opaque fiducials arranged for use in image calibration for an imaging system. The unit also includes a plurality of receivers positioned around a periphery of a detector in the imaging system for use in navigation calibration for the imaging system. The unit further includes a connection for providing data regarding image calibration and navigation calibration to a processor. Additionally, the unit includes a frame for positioning the array of radio opaque fiducials and the plurality of receivers embedded in a concave target with respect to a detector in the imaging system.

Abstract: The present invention relates to an implantable chamber (1) with a connecting element (2), comprising a connecting sleeve (6) and a surrounding contact surface (7), an insert element (3), comprising an insert sleeve (8) and a surrounding abutment surface (9). The insert sleeve (8) is inserted into the connecting sleeve (6) of the connecting element (2). The implantable chamber (1) further comprises a cap (4) with a surrounding edge (11), the cap (4) partly covering the connecting element (2) and the insert element (3), leaving an opening (13) on one side. The implantable chamber (1) contains a passive resonance circuit (14) with an inductance and a capacitance, the passive resonance circuit (14) surrounding at least part of a cavity (15) inside the insert element (3).

Abstract: An obturator with an elongated shaft, a proximal end, a substantially closed distal end and a MRI detectable distal shaft portion, which does not interfere with magnetic resonance imaging of tissue proximate thereto. Preferably, the distal shaft portion has an effective MRI detectable mass so as to provide a clear, T1-weighted image within an outline of the distal shaft portion upon magnetic resonance imaging.

Abstract: The invention relates to an MR method of determining local relaxation time values (T1, T2) of an examination object (5). Firstly, two or more MR images (3, 4) of the examination object (5) are recorded, each with different time parameter sets (TR1, TE1, TR2, TE2) of an imaging sequence. MR images (6, 7) of a phantom are likewise recorded, wherein the same time parameter sets (TR1, TE1, TR2, TE2) of the imaging sequence are used and wherein the phantom has a known spatial distribution of relaxation time values (T1, T2). The local relaxation time values (T1, T2) of the examination object (5) are determined by comparing image values of the MR images (3, 4) of the examination object (5) with image values of the MR images (6, 7) of the phantom and by assigning image values of the MR images of the phantom to relaxation time values (T1, T2) according to the known spatial distribution of relaxation time values (T1, T2) of the phantom.

Abstract: A marker delivery device is described which has an obturator with an elongated shaft, an inner lumen, a proximal end, and a substantially sealed distal end. One or more tissue markers are deployed within the inner lumen of the elongated shaft of the obturator. Preferably, the tissue marker(s) is disposed within an inner lumen of a marker delivery tube which is disposed within the inner lumen of the elongated shaft of the obturator. The marker delivery tube has an opening for discharging the tissue markers into a body (e.g. biopsy) cavity. The distal tip of the marker delivery tube is configured to penetrate the substantially sealed distal end of the obturator so that tissue markers can be delivered while the obturator is in place within the body. Preferably, the obturator includes a detectable element capable of producing a relatively significant image signature during MRI.

Abstract: A localization device display method and apparatus for displaying different views, e.g., of different magnification, based on the proximity of the tip of a pointer tracked by the localization device to a reference location identified by the localization device. The display method and apparatus may be incorporated into a surgical navigation system for use in identifying a location for drilling a femoral tunnel in an ACL repair procedure.

Abstract: An anchored fiducial apparatus is described. The fiducial apparatus anchors itself in the target region once inserted so that the fiducial apparatus does not move relative to the target region.

Abstract: An apparatus and a method for performing a medical procedure is disclosed. In an embodiment for an apparatus of the present invention, the apparatus includes a positioning system and a resection device disposed within the positioning system. The positioning system includes an imaging device, a video processor coupled to the imaging device, a computer coupled to the video processor, and a video display coupled to the computer. In an embodiment for a method of practicing the present invention, the method includes the steps of creating an image of a lesion within a patient's body on an imaging device. Data representative of the lesion image is processed by a video processor. Tissue margins around the lesion are defined by a processor based on the processed data representative of the lesion image and a resection device is operated during a resection procedure within the patient's body based upon the defined tissue margins.

Abstract: Featured is a system to determine the three-dimensional position and orientation of an effector (a needle, probe, or other medical instrument) relative to a subject using cross-sectional images (e.g. from a CT or MRI scanner). Also provided is a method for image guided effector placement that requires no immobilization of the patient or fiducial implantation. A localization module (fiducial object) is integrated or associated with the effector allowing for the localization of the effector in the image space using a single cross-sectional image.

Abstract: A medical device that inhibits distortion of medical resonance images taken of the device. In particular, various structures are utilized to allow visibility proximate, and inside of, a tubular member, such as a stent. In one embodiment, the stent does not contain electrically conductive loops. In an alternative embodiment, rings in the stent are arranged such that current in one ring portion is opposed by current in another ring portion.

Abstract: With the beam scanning probe system for surgery, a pointer indicating the observation point of a beam scanning probe is superimposed upon an image of a lesion to be operated on in the head which is obtained via a TV camera or a surgery microscope, and the superimposed image information is registered as such in an image recording device. With the beam scanning probe system for surgery, information of a cytological picture is also registered in the image recording device. With the beam scanning probe system for surgery, the image recording device registers the two image information in a paired fashion. Through this arrangement, the beam scanning probe system for surgery can smoothly locate, for a given cytological picture, a site of a tumor to be treated from which the picture was obtained, which will ease the operation.

Abstract: A registration artifact (10) for use in registering two or more fluoroscopic images includes a plurality of radio opaque spheres (12, 14, 16) and a plurality of trackable markers, such as optical reflectors (20, 22, 24 and 26), mounted to a radio transparent body (11). A tracking system locates the position of registrable artifact using the trackable markers for registering the fluoroscopic images with respect to a known frame of reference.

Abstract: The invention is directed biopsy site markers and methods of marking a biopsy site, so that the location of the biopsy cavity is readily visible by conventional imaging methods, particularly by ultrasonic imaging. The biopsy site markers of the invention have high ultrasound reflectivity, presenting a substantial acoustic signature from a small marker, so as to avoid obscuring diagnostic tissue features in subsequent imaging studies, and can be readily distinguished from biological features. The several disclosed embodiments of the biopsy site marker of the invention have a high contrast of acoustic impedance as placed in a tissue site, so as to efficiently reflect and scatter ultrasonic energy, and preferably include gas-filled internal pores. The markers may have a non-uniform surface contour to enhance the acoustic signature. The markers have a characteristic form which is recognizably artificial during medical imaging.