Surgery – Diagnostic testing – Sampling nonliquid body material
Reexamination Certificate
2001-05-07
2003-03-04
Bennett, Henry (Department: 3742)
Surgery
Diagnostic testing
Sampling nonliquid body material
C600S568000
Reexamination Certificate
active
06527731
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to fine needle aspiration (FNA), biopsy devices, and in particular to control systems for automatically controlling the operation of an FNA biopsy device so as to carry out a biopsy procedure.
STATUS OF PRIOR ART
A biopsy procedure involves the extraction of a small sample of living tissue from an internal mass in a patient, the extracted sample being then examined under a microscope in order to diagnose the patient's condition. Where and how a biopsy is to be performed depends on the internal site of the suspected mass. A biopsy is usually called for when other diagnostic techniques are unable to supply sufficient information on which to base a diagnosis. Thus a physician can by means of an ultrasound imaging instrument locate and observe an internal tumor in the body of a patient. But an ultrasound image of this tumor does not indicate whether it is benign or malignant. A biopsy is therefore necessary to make this determination.
A biopsy can be conducted either by an open or by a percutaneous method. An open biopsy entails an invasive surgical procedure to expose the internal region of interest so that one can then excise a portion of the suspected mass and examine it under a microscope. In a percutaneous biopsy, a large bore needle is used, making it necessary to make an incision in order to obtain a tissue sample from a suspected mass. A large bore needle carries with it the risk of tumor seeding along the biopsy tract.
The present invention deals with the least disturbing of biopsy techniques; namely: “Fine Needle Aspiration” (FNA). In an FNA technique, a fine needle projecting from a syringe is injected into a patient to impinge on an internal target from which the needle extracts a tissue sample constituted by a cluster of cells. The small sample picked up by the needle is then sucked into the syringe for cytologic examination under a microscope.
In an FNA biopsy procedure, it is vital that the injected needle be accurately directed to strike the target of interest and avoid adjacent tissues. When the target is palpable, such as a bulging thyroid gland, a physician has no difficulty in directing the needle toward the target. In this situation, all that a physician need do is to grasp in one hand the bulging tissue mass and with his other hand to inject the needle of the FNA device into the mass to extract a sample therefrom. The syringe is then operated to suck the sample from the needle into the syringe from which the sample is later removed for examination To facilitate such manual operations, various devices have been devised to hold the biopsy syringe. One such device for this purpose is disclosed in U.S. Pat. No. 5,493,130.
In those situations where the target for an FNA biopsy is not palpable but is deeply embedded in a patient's body, such as in the liver, then in order to be able to guide the needle toward the internal target one must be assisted by an imaging instrument, making it possible for the physician to see the internal target and the position of the fine needle relative thereto. The imaging instrument used for this purpose may be an ultrasound instrument or a computer-assisted tomograph (CAT or CT).
In the medical field, the reason ultrasound imaging is a preferred diagnostic tool is because of the non-ionizing character of ultrasound radiation. This makes ultrasound imaging safe and innocuous so that a patient may be repeatedly subjected in an ultrasound examination.
Sounds generated in an ultrasound instrument lie within a 1 to 10 mHz frequency range. These sounds are produced by a piezoelectric transducer caused to vibrate by an electronic pulse generator. When placed at a site overlying an internal target of interest, the piezoelectric transducer emits sonic pulses which are propagated through the body of the patient and reflected by interfaces between tissues having different acoustic impedances, thereby producing echo pulses which are received by the transducer. Signals from the transducer are applied to the cathode ray tube (CRT) of a monitor associated with the transducer on whose screen is displayed an image of the internal target of interest and the tissue to surrounding the target.
In order for an ultrasound instrument to accurately lead the needle of an FNA biopsy device toward an internal target when tissues are suspect and require diagnosis, it is known to provide the transducer of the instrument with a needle guide, such as the needle guide disclosed in the U.S. Pat. No. 5,924,992 to Park et al. This needle guide makes it possible for a physician to see on the CRT screen of the monitor associated with the transducer an image of the target of interest and of the biopsy needle as it advances toward this target. Also of prior art interest in regard to the use of an ultrasound instrument to perform real-time image-guided biopsy of tissue is U.S. Pat, 6,027,457 to Shmulewitz et al.
A biopsy needle guide for use with an ultrasonic probe in a medical procedure to accurately position a biopsy needle with respect to an internal target is also disclosed in U.S. Pat. 5,494,039 to Onik et al.
A needle inserting guide associated with an ultrasound probe makes it possible for a physician to properly direct the needle toward an internal target. But the guide does not relieve the physician of the need to manually operate the biopsy device so as to advance the needle toward the target to extract therefrom a tissue sample, to then withdraw the sample from the target, and finally to transfer the sample from the needle to the syringe.
Moreover, while the needle insertion guide simplifies the spatial relationship of the needle, the ultrasound probe and the internal target being biopsied it is an impediment to navigation and to a clear three-dimensional display of the tissues. One can therefore understand why investigators have reported that the sensitivity of a free-hand biopsy is greater than the sensitivity of a needle guide technique (see—Hatadet et al. Tumor 1999; 85;12).
Existing biopsy procedures present difficulties to a physician, for he must while viewing the CRT screen of an ultrasound imaging instrument at the same time be holding the transducer of this instrument against the body of the patient, and as he holds this transducer with one hand, he must with his other hand manipulate the FNA device first to inject the needle into the patient to obtain a sample, second to withdraw the needle, and third to operate the syringe to transfer the sample thereto.
A logical form of automatic control system for an FNA biopsy device would be a system in which electrically-powered miniature motors act to advance and retract the fine needle to extract a tissue sample from an internal target, and to then manipulate the syringe to transfer the sample from the needle to the syringe.
Of prior art interest in regard to a motor-driven automated biopsy device is the U.S. Pat. 5,980,469 to Burbank et al. However, conventional electrically-powered motors in a control system associated with a biopsy device in proximity to an ultrasound transducer through which the needle is guided cannot be tolerated. The reason for this is that relatively strong magnetic fields emanating from the motors and enveloping the transducer may interfere with its operation and distort the images appearing in the CRT screen. Moreover, a conventional motorized control system for a biopsy device which must be held by a physician in the course of a biopsy procedure enlarges the bulk and weight of the device and therefore makes it more difficult to handle.
Another drawback of a motor driven biopsy device is that it is difficult with a conventional motor to advance or retract the needle to the precise degree required by a biopsy procedure.
In our pending Israel Patent 140,494 filed Dec. 22, 2000, there is disclosed a pneumatic control system for automatically controlling the operation of an FNA biopsy device to be injected into a patient to extract a tissue sample from an internal target to be transferred to the syringe.
The control syst
Weiss David
Weiss Mordechai
Bennett Henry
Fish & Richardson P.C.
Patel Vinod D
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