Abstract: A hybrid imaging system includes a first imaging system configured to acquire anatomical data of a first field of view of an anatomical structure. A second imaging system configured to acquire functional data of the anatomical structure, the second imaging system acquiring functional data in a two-pass list-mode acquisition scheme. A reconstruction processor configured to reconstruct the functional data based on attenuation data into an attenuation corrected image and reconstruct the anatomical data into one or more high resolution images of one or more regions of interest.

Abstract: A method for determining functional severity of a stenosis includes: (a) generating a simulated perfusion map from a calculated blood flow; (b) comparing the simulated perfusion map to a measured perfusion map to identify a degree of mismatch therebetween, the measured perfusion map representing perfusion in a patient; (c) modifying a parameter in a model used in calculating the blood flow when the degree of mismatch meets or exceeds a predefined threshold; (d) computing a hemodynamic quantity from the simulated perfusion map when the degree of mismatch is less than the predefined threshold, the hemodynamic quantity being indicative of the functional severity of the stenosis; and (e) displaying the hemodynamic quantity. Systems for determining functional severity of a stenosis are described.

Abstract: A method and apparatus for precisely reproducing the position of a vaginal cylinder in relation to a patient to ensure that a planned radiation dose can be delivered with high precision to the intended treatment target volumes. Treatment delivery is carried out by using an image-guided system to locate the position of the vaginal cylinder and comparing it to the coordinate of the vaginal cylinder obtained in the treatment plan. The displacement in the position of the vaginal cylinder from the treatment plan is corrected by calculating the transformation matrix and entering the resulting value into a position adjusting assembly which is attached to vaginal cylinder. The position adjusting assembly adjusts the vaginal cylinder to exactly reproduce its location relative to the patient's anatomy, eliminating geometric and dosimetric error.

Abstract: A mammographic system which carries out a bioptic method for inserting a bioptic needle into a breast to sample a tissue from a bioptic region includes a display unit for displaying second stereoscopic images acquired by applying a radiation to the breast while the bioptic needle is being inserted in the breast, an indicating unit for indicating a pointed end of the bioptic needle and the bioptic region in each of the second stereoscopic images, a bioptic needle position calculator for calculating a three-dimensional coordinate position of the pointed end of the bioptic needle which is indicated, a bioptic region position calculator for calculating a three-dimensional coordinate position of the bioptic region which is indicated, and an angle calculator for calculating a direction of the calculated bioptic region with respect to the calculated pointed end of the bioptic needle and displaying the calculated direction on the display unit.

Abstract: The present invention includes a method of pre-planning a spherical fixed point stereotactic radiosurgery by obtaining an image from a patient having a target, the image comprising coordinates of the actual patient target in 3 dimensions on a first day; planning an optimal stereotactic radiosurgery using the patient's actual target using actual coordinates in 3 dimensions prior to the day of surgery by creating virtual radiosurgical coordinates and plans to maximize target exposure and minimize the patient's waiting time in radiosurgery, thereby allowing evaluation of several plans to maximize plan conformality and safety; and treating the patient based on the virtual stereotactic radiosurgery plans on a second day.

Abstract: A composite image is produced for use in HYPR processing a current image frame. The amount of a priori data used to form the composite is determined by the amount of subject motion. The current composite image may be spatially registered with the current image frame to offset subject motion before being used to form an updated composite image. Subject motion may be analyzed on a frame-by-frame basis, a region-by-region basis or a pixel-by-pixel basis to optimize the SNR of the updated composite image.

Abstract: Embodiments include a system for determining cardiovascular information for a patient. The system may include at least one computer system configured to receive patient-specific data regarding a geometry of the patient's heart, and create a three-dimensional model representing at least a portion of the patient's heart based on the patient-specific data. The at least one computer system may be further configured to create a physics-based model relating to a blood flow characteristic of the patient's heart and determine a fractional flow reserve within the patient's heart based on the three-dimensional model and the physics-based model.

Abstract: A system and method for measuring tissue motion within a living tissue of the anterior segment and aqueous outflow system of the eye in a subject are provided. Tissue movements are extracted from a plurality of images acquired from the living tissue using an optical coherence tomography system. The images may be corrected using motion compensation. To extract the tissue movements from the images, waves from a cardiac pulse or other externally induced pulses from the subject are acquired, and a pulse wave is defined for a given time, which is then correlated with a velocity wave defined for a velocity of tissue and/or fluid movement within the tissue region for the same given time. Pulsatile motion is then isolated in the tissue region from the plurality of images.

Abstract: A method, consisting of generating, using a plurality of magnetic transmitters, a magnetic field in a region and introducing a field perturbing element into the region. The method includes characterizing multiple images of each magnetic transmitter in the field perturbing element, and calculating a reaction magnetic field in the region based on the characterized images. The method further includes positioning a probe in the region and measuring a perturbed magnetic field at the probe, and determining a location of the probe in response to the measured perturbed magnetic field and the calculated reaction magnetic field.

Abstract: The present invention provides methods and compositions for modulating x-ray attenuation, where the x-ray attenuation compound can comprise a molecule having at least two conformational states, a first k-edge atom attached to the molecule at a first position, and a second k-edge atom attached to the molecule at a second position, where the molecule changes from a first conformational state to a second conformational state in response to an external stimulus. Additionally, a first interatom distance between the first k-edge atom and the second k-edge atom in the first conformational state can be within a first harmonic error of 0 to about 0.2, and a second interatom distance between the first k-edge atom and the second k-edge atom in the second conformational state can be within a second harmonic error of about 0.8 to 1.0.

Abstract: A system for determining a functional property of a moving object includes a tag contactable to the object such that the tag follows the movement of the object. The system further includes a movement determination device configured to determine the movement of the tag. The system also includes a functional property determination device configured to determine a functional property of the object from the determined movement of the tag.

Abstract: A system and method for treating tissue uses an ultrasound therapy system including an ultrasonic applicator having has at least one transducer element. Steering and focusing of ultrasound beams uses at least one variable focus lens, which may be a fluid focus lens, attached to each transducer element so that focus of the variable focus lens is controlled by a voltage signal. A treatment controller receives input from an imager and controls the voltage applied to the variable focus lens. The treatment controller controls the lens voltage signals, at least partially determined by the input from the imager, and directs an ultrasonic treatment beam emitted by the transducer element. Fine adjustment of the therapy beam is achieved to deliver therapy for various prostate sizes and shapes while avoiding damage to critical structures such as the rectal wall and nerve bundles.

Abstract: Methods of performing a power injection procedure are described. One method includes taking an x-ray of a subcutaneously implanted access port in a patient to determine whether the access port includes a radiographic feature indicating that the access port is suitable for flowing fluid at a rate of at least about 1 milliliter per second through the access port, identifying the indicating radiographic feature on the x-ray, and flowing a fluid through the access port at a rate of at least about 1 milliliter per second.

Abstract: This invention will introduce a fast and effective target approach planning method preferably for needle guided percutaneous interventions using a rotational X-ray device. According to an exemplary embodiment A targeting method for targeting a first object in an object under examination is provided, wherein the method comprises selecting a first two-dimensional image of an three-dimensional data volume representing the object under examination, determining a target point in the first two-dimensional image, displaying an image of the three-dimensional data volume with the selected target point.

Abstract: A system for displaying lung ventilation information, the system comprising an input (12) and a processing unit (15). The input being provided for receiving multiple CT images (71) of a lung, each CT image (71) corresponding to one phase of at least two different phases in a respiratory cycle. The processing unit (15) being configured to compare CT images (71) corresponding to different phases in the respiratory cycle for determining a deformation vector field for each phase, to generate for each phase a ventilation image (72) based on the corresponding deformation vector field, to spatially align the ventilation images (72), and to generate for at least one common position (62) in each one of the aligned ventilation images (72), a function (81) of a time course of a ventilation value for said common position (62), each ventilation value in the function (81) being based on the deformation vector fields corresponding to the aligned ventilation images (73).

Abstract: We provide a radiotherapy apparatus including a source of therapeutic radiation, a source of imaging radiation having an energy level less than that of the therapeutic radiation, a detector for radiation lying within the field of both the therapeutic radiation and the imaging radiation and able to image both, a first imaging circuit supplied with the output of the detector, a second imaging circuit also supplied with the output of the detector, a first pulse trigger circuit adapted to trigger the source of therapeutic radiation to produce a pulse of therapeutic radiation and to trigger the first imaging circuit to capture an output of the detector; and a second pulse trigger circuit adapted to trigger the source of imaging radiation to produce a pulse of imaging radiation and to trigger the second imaging circuit to capture an output of the detector.

Abstract: A dual-modality apparatus for imaging of biological tissue includes a reflectance confocal microscopy (RCM) imaging apparatus and an optical coherence tomography (OCT) imaging apparatus. A first optical component reflects a first beam of light provided by a RCM imaging apparatus towards a sample and passes a second beam of light provided by an OCT imaging apparatus towards the sample, such that the first and second beam of lights share at least a portion of an imaging path.

Abstract: A catheter device for crossing occlusions includes an elongate body, a central lumen extending within the elongate body from the proximal end to the distal end, a rotatable tip at the distal end of the elongate body, and an OCT imaging sensor. The rotatable tip is configured to rotate relative to the elongate body. The OCT imaging sensor includes an optical fiber coupled with the rotatable tip and configured to rotate therewith. A distal end of the elongate body includes one or more markers configured to occlude the OCT imaging sensor as it rotates. A fixed jog in the elongate body proximal to the distal end of the catheter positions the distal end of the catheter at an angle relative to the region of the catheter proximal to the fixed jog and is aligned with the one or more markers on the elongate body.

Abstract: In one embodiment of the invention, a method is disclosed to locate a robotic instrument in the field of view of a camera. The method includes capturing sequential images in a field of view of a camera. The sequential images are correlated between successive views. The method further includes receiving a kinematic datum to provide an approximate location of the robotic instrument and then analyzing the sequential images in response to the approximate location of the robotic instrument. An additional method for robotic systems is disclosed. Further disclosed is a method for indicating tool entrance into the field of view of a camera.

Abstract: A catheter procedure system including a user interface for receiving at least a first user input and a second user input and a guide catheter is provided. The catheter procedure system also includes a guide catheter actuating mechanism coupled to the guide catheter and a Y-connector. The guide catheter actuating mechanism is configured to advance and retract the guide catheter in response to the first user input and to rotate the guide catheter in response to the second user input. The catheter procedure system includes a first connector coupling the Y-connector to the guide catheter actuating mechanism, and the first connector is configured to allow the Y-connector to advance and retract with the guide catheter and to allow the guide catheter to rotate without also causing the Y-connector to rotate.

Abstract: Disclosed are embodiments of methods of and systems for detecting and biopsying lesions with a cone beam computed tomography (CBCT) system. The system comprises, in some embodiments, a CBCT device configured to output a cone beam CT image of at least a portion of a patient's breast and a multi-axis transport module, having at least three degrees of freedom and configured to position a biopsy needle within a 3D frame of reference based on inputs received from the cone beam CT device. The transport module can be configured to place the biopsy needle adjacent to, or within, a target of interest within the breast. Also disclosed are embodiments of methods of and systems for testing CBCT systems with phantoms.

Abstract: In a method and an apparatus for conducting minimally-invasive procedures involving heart valves at least one multi-access articulated x-ray imaging robot is employed that allows a radiation detector carried by the robot to be moved in arbitrary paths, such as in circle, an ellipse, or along a spiral, around a patient in order to generate multiple projection exposures of the relevant region of the patient during the procedure. An image processor reconstructs a 3D image from the projection exposures substantially in real time during the procedure, and the 3D image is displayed to operating personnel during the procedure.

Abstract: An instrument adapted for the infusion of a catheter into a vessel or performing a biopsy procedure is in the form of a needle with an OCT probe affixed adjacent its distal end. An optics cable extends from the probe to an optoelectronics module which supplies light to, receives reflected light from the probe and deciphers the reflected light to form an image of the tissue 2-3 mm in from to the probe. A catheter may be placed over the instrument for insertion into a vessel or vein or the instrument may be provided with a tissue receiving channel for biopsy use.

Abstract: Determining a shape of a medical device to be implanted into a subject produces an image including a defective portion and a non-defective portion of a surface of a tissue of interest included in the subject. The tissue of interest is segmented within the image. A template, representing a normative shape of an external anatomical surface of the tissue of interest, is superimposed to span the defective portion. An external shape of an implant, is determined as a function of respective shapes of the defective portion as seen in the template, for repairing the defective portion.

Abstract: The system and method of the present application includes an image guided radiation therapy (IGRT) system, combined with a medical ventilator, to form a closed-loop system to optimize treatment of a tumor for patients who cannot comply with a normal respiratory management procedure. The ventilator may be used to generate respiratory maneuvers to facilitate clean images for dose planning, so that clinicians can more clearly visualize a target with fewer of the image artifacts associated with respiratory motion. The combined IGRT and ventilation systems approach facilitates treatment of specific organs most susceptible to respiratory motion artifact, and helps minimize the doses to the heart in left-breast treatments. Improved positioning of the anatomical target structures for exposure to external beam radiation may be accomplished through combinations of respiratory-gating, respiratory pause, and selective right or left lung mechanical ventilator techniques.

Abstract: A system for tracking the position of an instrument relative to an area of interest includes a first fixator configured to carry first and second localizing devices. A second fixator is configured to carry the first localizing device. A third localizing device communicates with the first localizing device and the second localizing device communicates with the first localizing device such that the position of the second localizing device can be determined relative to the position of the third localizing device. The second localizing device is attachable to the instrument and the first localizing device is attachable to the first fixator such that the first localizing device communicates with the second localizing device on the instrument in order that the position of the second localizing device on the instrument can be determined relative to the third localizing device.

Abstract: Various methods and devices for minimally invasive treatment and prevention of conditions of the fascia are provided. In one aspect, a method includes providing an acoustic wave source effective to deliver a focused acoustic wave to a target site within a patient's body, and focusing an acoustic wave through a patient's skin such that at least one location in the patient's fascia is fenestrated in a desired pattern.

Abstract: Disclosed are methods and systems for non-invasive neuromodulation using ultrasound for cognitive enhancement. Cognitive enhancement can be used for mitigation of abnormal conditions such as Alzheimer's Disease, Parkinson's Disease or stroke, or for enhancement in a normal individual. The neuromodulation can produce acute or long-term effects. The latter occur through Long-Term Depression (LTD) and Long-Term Potentiation (LTP) via training. Included is control of direction of the energy emission, intensity, frequency, pulse duration, pulse pattern, mechanical perturbation, and phase/intensity relationships to targeting and accomplishing up regulation and/or down regulation.

Abstract: Apparatus for accurate positioning of a needle guide is disclosed. The apparatus provides a means for taking as input the position vector for the point of insertion of the needle into the body. This point of insertion can be selected from images produced by a Computer Tomography system. Similarly, the apparatus has a means for taking as input the point of target. A controller determines the directional vector between point of insertion and point of target. A guide manipulator accurately positions the needle guide in line with the directional vector, such that the needle can easily be inserted through the guide to the point of target. The positioning of the guide manipulator in accordance with the directional vector is done with the help of motors.

Abstract: A method for performing computer-assisted orthopaedic surgery includes the steps of: (1) producing and displaying three-dimensional geometrical models of first and second bones, the first and second bones forming a joint; (2) identifying a zone of impingement between the first bone and the second bone on at least one of the bones; and (3) generating and displaying a color map of at least one surface of at least one bone, the at least one surface being within the zone of impingement, the color map including different colors representing different depths of bone to be removed in order to achieve an increased range of motion between the first and second bones.

Abstract: Systems and methods for photoacoustic imaging are provided. Photoacoustic signals are excited from a body and the excited photoacoustic signals are detected with a low coherence interferometer system serving as a photoacoustic detector. Cross-sectional images of the body are then reconstructed by the system from the detected photoacoustic signals.

Abstract: An optical coherence tomography system and method with integrated pressure measurement. In one embodiment the system includes an interferometer including: a wavelength swept laser; a source arm in communication with the wavelength swept laser; a reference arm in communication with a reference reflector; a first photodetector having a signal output; a detector arm in communication with the first photodetector, a probe interface; a sample arm in communication with a first optical connector of the probe interface; an acquisition and display system comprising: an A/D converter having a signal input in communication with the first photodetector signal output and a signal output; a processor system in communication with the A/D converter signal output; and a display in communication with the processor system; and a probe comprising a pressure sensor and configured for connection to the first optical connector of the probe interface, wherein the pressure transducer comprises an optical pressure transducer.

Abstract: Allows the specificity of an automatic MRT detection to be increased in a simple manner. This is achieved using an automatically calibrating position sensor, so that the user does not have to perform additional calibration of this sensor. Incorrect sensor calibrations are thus eliminated as well.

Abstract: A system and apparatus allows the tracking of a selected body portion, instrument, or both. A tracking device can be interconnected to a body portion at a mounting site. A procedure can be performed at a location remote from the mounting site of the tracking device. The tracking device can be interconnected with the body in a low invasive manner.

Abstract: A scanning assembly for a dual-modality automated biological tissue imaging device having first and second compression surfaces is provided. The system comprises a housing defining a scanning/compression surface, an ultrasonic transducer mounted within the housing adjacent the scanning surface for movement in a plane parallel to the scanning surface and imaging the tissue through the scanning surface, an X-ray detector mounted within the housing for forming an X-ray image of the tissue based on X-ray radiation passed through the tissue and scanning surface from an X-ray source, and a drive for moving the transducer across the scanning surface so that the transducer generates a plurality of two-dimensional ultrasound tissue images. The housing is hermetically sealed and filled with non-conductive fluid with acoustic impedance resembling that of the tissue. The scanning surface has acoustic impedance resembling that of the tissue and can substantially withstand compression forces applied to the tissue.

Abstract: Systems and methods for obtaining and processing data collected using a multi-site intravascular sensing device are provided. Some embodiments are directed to locating a structure within a vessel and performing an examination of the structure once it has been located. In one embodiment, an elongate member has a plurality of sensors and set of measurements is obtained using the plurality of sensors, the set of measurements including at least one measurement from each sensor of the plurality of sensors. The various sensor measurements are compared and a difference in a vascular characteristic is determined from the compared measurements. The location of the structure may be determined based on the adjacent sensors.

Abstract: Disclosed are medical probe devices and methods for use guiding of percutaneous probes during medical procedures. The probe devices include an ultrasound transducer housing having a passage therethrough configured to accommodate a probe. The devices can be utilized to guide a probe through the probe guide to a percutaneous target with real time visualization of the probe during the procedure. In addition, the devices can include a sterilizable shield including a sterile probe guide such that the transducer housing itself can be separated from a subject by a sterile barrier. The sterilizable shield can be a single-use shield that can prevent contamination and re-use of the shield. The devices can define a beneficial geometry conducive to use by a single operator that can be utilized for percutaneous targets near the skin surface and can enable excellent contact between the device and the skin surface of a subject.

Abstract: A target tracking device for tracking a moving target, based on X-ray fluoroscopic images from a plurality of directions, the target tracking device may include a plurality of X-ray fluoroscopic devices, an image processing unit, and a position determining unit. The X-ray fluoroscopic devices obtain a plurality of images from a plurality of directions, each of the images in a given direction having a different sensitivity. The image processing unit identifies a position of a target image based on pattern matching between the plurality of images and an image of the target. The position determining unit determines a 3D position of the target based on the position of the target image in the plurality of images from the plurality of directions.

Abstract: A method for detecting the position of a transducer for monitoring the position and motion of one or more target structures for the preparation or during an operation, with creating at least one volume data set (CT or MRI) showing the target structure(s), possible contact surfaces for the positioning of the ultrasonic transducer and the tissue between contact surfaces and target structure(s), determining from the volume data set one or more contact surfaces on which the best reflection of the ultrasound is or are to be expected, and positioning the ultrasonic transducer which monitors the operation on the contact surface(s).

Abstract: A system and method are provided for determining individualized scan and injection protocols for contrast-enhanced diagnostic imaging. Taking into account parameters specific to the scan subject, injection-related parameters, and scan parameters, the system and method can determine an optimal timing for a scan sequence to begin, to ensure that the scan sequence coincides with a desired contrast enhancement. Some embodiments further provide for real-time triggering of the scan commencement based on bolus tracking, and can adapt the scan and injection protocols in real-time based on monitored dynamic scan subject parameters and/or actual enhancement values determined from image data.

Abstract: An in vivo imaging device including at least two imaging modalities. In one aspect, the device includes a rotational imaging system in combination with a non-rotational imaging system. Systems including the imaging device, and methods of forming and in vivo imaging using a flexible, elongate body that includes two imaging modalities are also disclosed.

Abstract: A catheter includes a fluid network for cooling the ablation electrode, surrounding blood and tissue. The fluid network comprises a circumferential channel having an annular shape and fluidly coupled to at least one proximal longitudinal channel configured to conduct fluid along a proximal length of the catheter. The circumferential channel is configured to conduct fluid about at least a circumferential portion of the catheter. The fluid network further comprises a plurality of distal longitudinal channels fluidly coupled to the circumferential channel, with the plurality of distal longitudinal channels being configured to conduct fluid a long a distal length of the catheter. The fluid network occupies a region of the catheter peripheral to a central longitudinal axis of the catheter such that other components of the irrigated catheter, including at least one imaging sensor, is disposed within the central region of the ablation electrode.

Abstract: A procedure for determining a plan for cutting a bone sample for use as an implant provides scanning the bone with a CT scanning system to provide slice images of the bone. The scanning system then determines the cortical or cancellous bone dimensions and density of the bone. Determining such dimensions and density permits accurate planning and preparation of an implant graft that is correlated to the predetermined plan without waste of bone through cutting test specimens to determine the bone parameters. Other images techniques that provide slice images are also disclosed.

Abstract: The invention relates to a real time radiation treatment planning system for use in effecting radiation therapy of a pre-selected anatomical portion of an animal body using hollow needles. According to embodiments of the invention, the system may include a processing means processing means-configured to perform a three-dimensional imaging algorithm and a three-dimensional image segmentation algorithm, with respect to one or more specific organs within the pre-selected anatomical portion and with respect to the needles, for converting the image data obtained with an imaging means into a three-dimensional image of the anatomical portion, using at least one single or multi-objective anatomy-based genetic optimization algorithm.

Abstract: Embodiments include a system for determining cardiovascular information for a patient. The system may include at least one computer system configured to receive patient-specific data regarding a geometry of the patients heart, and create a three-dimensional model representing at least a portion of the patient's heart based on the patient-specific data. The at least one computer system may be further configured to create a physics-based model relating to a blood flow characteristic of the patient's heart and determine a fractional flow reserve within the patient's heart based on the three-dimensional model and the physics-based model.

Abstract: A remote control system capable of precise operations or treatments in which the visual recognition and operation portions are as close to each other as possible, including: a) an imaging device for taking an image of the object; b) a manipulation tool having at its tip an illuminator for casting a spot light onto the object; c) a driver for changing the position of the manipulation tool; d) an external display unit for displaying an image; e) an input unit for allowing an operator to specify a position corresponding to the display of the external display unit; f) a distance calculator for calculating the distance between the position specified through the input unit and the position of the spot light cast from the illuminator onto the object; and g) a controller for controlling, based on the aforementioned distance, the driver so as to bring the tip of the manipulation tool closer to the specified position.

Abstract: In a method and system for planning and implementing a selective internal radiation therapy (SIRT), the liver volume and the tumor volume are automatically calculated in a processor by analysis of items segmented from images obtained from the patient using one or more imaging modalities, with the administration of a contrast agent. The volume of therapeutic agent that is necessary to treat the tumor is automatically calculated from the liver volume, the tumor volume, and the body surface area of the patient and the lung shunt percentage for the patient. The therapeutic agent can be administered via respective feeder vessels in respectively different amounts that correspond to the percentage of blood supply to the tumor from the respective feeder vessels, this distribution also being automatically calculated by analysis of one or more parenchymal blood volume (PBV) images.

Abstract: In part, the invention relates to catheters, methods, and blood clearing technologies suitable for use in an optical coherence tomography system. The optical coherence tomography system includes a control system, a probe including a catheter defining a lumen and a rotatable optical fiber located within the lumen, a fluid cartridge holder in communication with the lumen of the probe, a pump to move fluid from the fluid cartridge to the lumen of the probe; and a motor configured to rotate and pull the optical fiber through the lumen of a blood vessel. The pump and the motor are controlled by the control system. The catheter can include a wall that bounds the lumen of the probe, which defines a flush port and includes a valve in fluid communication with the flush port, the valve configured to permit fluid from the lumen to pass through the wall.

Abstract: A navigation system or combination of navigation systems can be used to provide two or more types of navigation or modalities of navigation to navigate a single instrument. The single instrument can be positioned within the patient and tracked. For example, both an Electromagnetic (EM) and Electropotential (EP) navigation system can be used to navigate an instrument within a patient.

Abstract: A method for planning a needle path is provided. The method includes displaying a restricted region on a display, the restricted region being defined by spatial limitations of an imaging system and a location of a selected target point; and selecting a skin entry point outside the restricted region.