Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
1998-02-25
2003-06-17
Smith, Ruth S. (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C600S427000, C600S429000
Reexamination Certificate
active
06580938
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to methods and apparatus for performing medical procedures in the thorax of a medical or veterinary patient.
Some common medical procedures require the ability to operate on a specific location in the thorax, including locations in the respiratory system, such as the lungs, bronchi and immediately surrounding tissues. For example, needle aspiration biopsies have been performed heretofore using an endoscope inserted through the trachea into a bronchus. The needle is advanced through the endoscope through the bronchial wall to sample tissue in a lymph node within the lung parenchyma near the exterior surface of the bronchus. The physician can monitor placement of the endoscope and the biopsy needle using the optical system of the endoscope. As the endoscope is advanced toward the area to be sampled, the physician can determine where the tip of the endoscope lies by observing features of the airway itself. However, it is difficult to place a biopsy needle within a particular lymph node using this approach. The physician cannot see the lymph nodes, which lie outside of the airway. Therefore, the physician can only position the endoscope tip and the biopsy needle at an approximate position, near the location of the lymph node to be biopsied. For this reason, there has been a significant need for improvement in the reliability of needle aspiration biopsies of the lymph nodes surrounding the respiratory tract. There have been similar needs for improvement in other biopsies procedures using a probe advanced into the body, such as a biopsy needle or biopsy forceps to sample tissues in the vicinity of the respiratory tract. There have been similar needs for improvement in other procedures where a probe is advanced into the tissues of the thorax for other purposes as, for example, to perform surgical procedures on these tissues or to administer drugs within these tissues.
Some procedures heretofore have used imaging during advancement of the probe to provide guidance. Thus, as the probe is advanced, the probe and the body are imaged using conventional imaging techniques such as fluoroscopy or magnetic resonance imaging. This allows the physician to observe the relationship between the position of the probe and the surrounding tissues. These procedures have the disadvantage that the imaging apparatus is occupied for the entire time required to perform the procedure. Moreover, the use of fluoroscopic or other x-ray based imaging modalities during the procedure exposes the physician and the patient to radiation.
As described, for example, in U.S. Pat. Nos. 5,558,091, 5,391,199; 5,443,489; and in PCT International Publication WO 96/05768, the disclosures of which are hereby incorporated by reference herein, the position, orientation or both of the distal end of a probe can be determined by using one or more field transducers such as a Hall effect or magnetoresistive device, coil or other antenna carried on the probe, typically at or adjacent the distal end of the probe. One or more additional field transducers are disposed outside the body in an external frame of reference. The field transducers preferably are arranged to detect or transmit non-ionizing fields or field components such as a magnetic field, electromagnetic radiation or acoustical energy such as ultrasonic vibration. By transmitting the field between the external field transducers and the field transducers on the probe, characteristics of field transmission between these devices can be determined. The position and/or orientation of the sensor in the external frame of reference can then be deduced from these transmission characteristics. Because the field transducer of the probe allows determination of the position of the probe, such transducer is also referred to as a “position sensor”.
As described, for example, in the aforementioned U.S. Pat. No. 5,558,091, the frame of reference of the external field transducers can be registered with the frame of reference of imaging data such as magnetic resonance imaging data, computerized axial tomographic data, or conventional x-ray image data. The probe position and orientation data derived by field transmission can be displayed as a representation of the probe superimposed on an image of the patient's body. The physician can use this information to guide the probe to the desired location within the patient's body, and to monitor its orientation during treatment or measurement of the body structure. This arrangement greatly enhances the ability of the physician to navigate the distal end of the probe through bodily structures. Because it does not require acquisition of an optical image of the surrounding tissues for navigation purposes, it can be used with probes which are too small to accommodate optical elements, and can be used for navigation of the probe within solid or semisolid tissues. The transducer-based system also avoids the difficulties associated with navigation of a probe by continuous imaging of the probe and patient during the procedure. For example, it avoids exposure to ionizing radiation inherent in fluoroscopic systems.
Some additional problems are encountered in use of systems of this type for procedures in the thorax near the respiratory system. As the patient breathes, the positions, sizes and shapes of the thoracic organs change. Thus, if an image of the patient is acquired at one stage of the respiratory cycle, the image data does not accurately represent the patient during other stages. Therefore, if the position of the probe is detected while the patient is in one stage of the respiratory cycle, and this probe position data is combined with patient image data from another stage of the respiratory cycle to provide an image with a representation of the probe superposed thereon, the location of the probe relative to the surrounding organs will be depicted inaccurately.
As described in International Publication WO 97/29709, the disclosure of which is incorporated by reference herein, problems of this nature can be avoided by positioning a first probe, referred to as a “site probe” within the body of the patient at a location to be treated, and providing a further probe, referred to as an “instrument probe” for performing the medical procedure. The site probe is positioned within the body at the location to be treated as, for example, at a location to be biopsied. Using a location system such as the magnetic location systems discussed in the aforementioned patents, the locations of both probes are monitored during the medical procedure. Therefore, the distance and direction from the instrument probe to the site probe are known during the medical procedure, despite any motion caused by the patient's breathing. Using that directional and distance information, the physician can navigate the instrument probe to the site probe.
PCT Publication WO 97/29682 refers to systems for determining the “physiological motion” such as breathing motion or cardiac motion of a portion of the body in which a probe is situated. Using a device such as a belly strap to sense breathing motion, the system selects a “correct” image from a set of previously obtained images at each instant during the procedure, or interpolates between images. Thus, the displayed image always reflects the actual size and shape of the organs at the instant in question. Accordingly, the representation of the probe can be accurately superposed on the display image.
U.S. Pat. No. 5,577,502 discloses a system in which the position of the subject's chest is monitored by devices such as optical, ultrasound or mechanical tracking elements. Based on that positional tracking, the image used in a superposition system is distorted so as to provide a corrected image which changes as the subject breathes. The position of the probe can be superposed on the corrected image. Systems of this type require considerable computation to distort the reference image as the patient moves through various stages of the respiratory cycle. Moreover, additional e
Biosense Inc.
Lerner David Littenberg Krumholz & Mentlik LLP
Smith Ruth S.
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