Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
1998-10-23
2001-08-07
Lateef, Marvin M. (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C250S336100, C250S370010
Reexamination Certificate
active
06272373
ABSTRACT:
BACKGROUND OF THE INVENTION
Current and historical procedures for treatment of colon and rectal cancer generally have been based upon the natural history of tumor spread, and thence, upon operative and non-operative options available to the practitioner. Operative options generally have looked to the physical identification and surgical resection of tumor. A variety of techniques have been brought to bear in the art with the purpose of aiding the surgeon in detecting and localizing neoplastic tissue as part of this surgical procedure. (“Neoplastic tissue,” for the present purposes, often is referred to as cancerous tissue, though malignant tumor and malignant tumor cells also are found in the terminology of the art. The term “neoplastic tissue” includes all of these.) A substantial amount of the effort which has been expended in seeking to aid the surgeon in the process of locating neoplastic tissue has been concerned with the utilization of radiolabeled antibody. For example, one technique includes the scintillation scanning of patients who have been injected with relatively high energy, e.g.
131
I labeled antibodies. Such photoscanning scintigrams are difficult to interpret because of blood pool background radioactivity. Computer subtraction of radioactive blood pool agents and the use of two labeled antibodies (one specific for the tumor and one non-specific) have been attempted in an effort to enhance imaging. Nevertheless, such techniques have been found to provide little, if any, useful information to the surgeon, especially over and above the CAT scan, magnetic resonance imaging, and like traditional techniques. Typically, large tumor is readily located by the surgeon by visualization at the operating theater, and, in particular, through palpation, i.e. the feel of tumor as opposed to that of normal tissue. To achieve operative success, however, it is necessary for the surgeon to somehow locate “occult” tumor, i.e. tumor which cannot be found by the conventional surgical procedures of sight and feel. Failure to locate and remove such occult tumor generally will result in the continued growth of cancer in the patient, a condition often referred to as “recurrent” cancer. In general, conventional diagnostic techniques such as, for example, use of the classic gamma camera and the like, fail to find or locate occult tumor. As tumor sites become smaller, the radionuclide concentrations at a given site will tend to be lost, from an imaging standpoint, in the background where blood pool radiation necessarily is present in the patient.
In 1984, Martin, M. D., and Thurston, Ph.D., introduced a much improved method for locating, differentiating, and removing neoplasms. Such technique uses a radiolabeled antibody and a portable radiation detection probe which the surgeon may use intraoperatively in order to detect sites of radioactivity. Because of the proximity of the detection probe to the labeled antibody, the faint radiation emanating from occult sites becomes detectable, for example, in part because of the inherent application of the approximate inverse square law of radiation propagation. The procedure now is known as radioimmunoguided surgery (RIGS®) (RIGS being a registered trademark of Neoprobe Corporation of Dublin, Ohio). The RIGS system for surgery additionally is successful because of a recognition that tumor detection should be delayed until the blood pool background of the circulating radiolabeled antibody has had an opportunity to be cleared from the body. As a consequence, the photon emissions or radiation emitted at minute tumors, compared to surrounding tissue, becomes detectable in view of the proximity of the probe device to it. Fortuitously, the radiolabeled antibody is capable of remaining bound to or associated with neoplastic tissue for extended periods of time with the radio tag still bound thereto. Moreover, even though the accretion of radioactivity at the tumor site decreases over time, the blood pool background and surrounding tissue (relative to the tumor sites) decrease at a much greater rate so that the radioactive sites can be determined readily utilizing a hand-held probe positioned in close proximity with the tissue under investigation. The seminal patent concerned with the RIGS procedure is U.S. Pat. No. 4,782,840 by Martin and Thurston, entitled “Method for Locating, Differentiating, and Removing Neoplasms,” issued November 8, 1988, and assigned in common herewith, the disclosure of which is expressly incorporated herein by reference.
The important advances achieved through radioimmunoguided-surgery have been reported. See in this regard, the following publications:
(1) “Radioimmunoguided Surgery system Improves Survival for Patients with Recurrent Colorectal Cancer” Bertsch, et al., Surgery 1995; 118: 634-639.
(2) “Radioimmunoguided Surgery in Primary Colorectal Carcinoma: An Intraoperative Prognostic Tool and Adjuvant to Traditional Staging,” Arnold, etal.,
American J. Surg
. 1995; 179:315-318.
(3) “The Significance of Intraoperative Periportal Lymph Node Metastasis Identification in Patients with Colorectal Carcinoma,” Schneebaum, et al., Cancer 1995; 75: 2809-2817.
(4) “Identification of Occult Micrometastases in Pericolic Lymph Nodes of Dukes' B Colorectal Cancer Patients Using Monoclonal Antibodies against Cytokeratin and CC49,” Greenson, et al., Cancer 1994; 73: 563-569.
(5) “Intraoperative Detection of Occult Colon Cancer Micrometastases Using
125
I-Radiolabeled Monoclonal Antibody CC49,” Cote, et al., Cancer 1996; 77: 613-620.
The radioimmunoguided surgical system instrumentation is comprised generally of two basic components, a hand-held probe, as described above, which is in electrical communication via a flexible cable with a control console. This control console is located within the operating room facility but out of the sterile field, while the hand-held probe and forward portions of its associated cable are located within that field. The hand-held radiation detecting probe is relatively small and performs in conjunction with a cadmium-zinc-telluride detector or crystal.
The hand-held probe and preamplification electronics mounted within it in support of the cadmium-zinc-telluride crystal have been the subject of extensive scientific development. Cadmium-zinc-telluride crystals are somewhat fragile and exhibit piezoelectric properties which, without rigorous accommodation, will produce deleterious noise phenomena and the like. Further, the crystal and its operatively associated preamplification function are called upon to detect necessarily very faint radiation. In this regard, only a very small amount of radioactive locator will be associated with minute, occult tumor. Thus, radiation emission count rates measured with the RIGS system are relatively low. Research activity concerning the above operational criteria is reflected in the following U.S. Patents.
U.S. Pat. No. 4,801,803 by Denen, Thurston and Ramsey, entitled “Detector and Localizer for Low Energy Radiation Emissions,” issued Jan. 31, 1989.
U.S. Pat. No. 4,893,013 by Denen, Thurston and Ramsey, entitled “Detector and Localizer for Low Energy Radiation Emissions,” issued Jan. 9, 1990.
U.S. Pat. No. 5,070,878 by Denen, entitled “Detector and Localizer for Low Energy Radiation Emissions,” issued Dec. 10, 1991.
U.S. Pat. No. 5,151,598 by Denen, entitled “Detector and Localizer for Low Energy Radiation Emissions,” issued Sep. 29, 1992.
To derive data representing the presence or absence of occult tumor, a microprocessor-driven complex system of analysis continuously works to statistically evaluate validated counts or gamma strikes to aurally apprise the surgeon of the presence or absence of occult neoplastic tissue. One algorithm under which the noted evaluation takes place is described in U.S. Pat. No. 4,889,991 by Ramsey and Thurston, entitled “Gamma Radiation Detector with Enhanced Signal Treatment,” issued Dec. 26, 1989.
The RIGS system, not only having demonstrated its value in locating occult neoplastic tissue, also substantially aids the surgeon in determini
Lateef Marvin M.
Mercador Eleni Mantis
Mueller and Smith LPA
Neoprobe Corporation
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