Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
2001-09-26
2003-10-21
Shaw, Shawna J. (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C600S436000, C600S475000
Reexamination Certificate
active
06636755
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to a method and apparatus for obtaining an optical tomographic image of a sentinel lymph node, and in particular, to detecting the sentinel lymph node, into which tumor cells first enter the lymph system from the primary nidus of a tumor, and obtaining an optical tomographic image of the sentinel lymph node.
2. Description of the Related Art
Recent years have seen increased rates in the early detection of cancer and the like, and cancerous and other diseased tissues are frequently surgically removed in the early stages of a disease. Generally, the objective of early surgical removal of cancerous tissue is the complete arresting of the disease, and frequently, in addition to the diseased tissue, a plurality of lymph nodes in the area surrounding the diseased tissue, from which there is a suspected danger of metastasis of the disease, are also removed. In addition, a test for pathology is performed on the excised lymph nodes to confirm whether or not the disease has metastasized thereto, and the course of post-surgical treatment is determined.
Due to the fact that it is not known whether or not the disease has metastasized to the lymph nodes during the performance of the surgical removal thereof, a plurality of lymph nodes in the surrounding vicinity of the diseased tissue is removed, and the burden on the patient is therefore great. Further, in the early stages of breast cancer, for example, the rate of metastasis of the disease to lymph nodes is 20 percent; for the 80 percent of the patients in whom the disease has not metastasized to the lymph nodes, the removal thereof is unnecessary.
In recent years, both the complete halting of the disease through surgical removal of the cancerous tissue and the preservation of the QOL (Quality of Life) of the patient are sought. To this end, one surgical method that has received much attention, which is aimed at preventing unnecessary removal of lymph nodes, is sentinel node navigation surgery. Hereinafter, a simple explanation of sentinel node navigation surgery will be given.
For cases in which cancer has metastasized to lymph nodes, it has become clear, in light of recent research, that it does not metastasize randomly, but is metastasize through the lymph system to the lymph nodes according to a set pattern. The first lymph node into which cancer cells enter from the primary nidus of a cancer is called a sentinel lymph node; it is held that for cases in which cancer has metastasized to the lymph nodes, the cancer has definitely metastasized to a sentinel lymph node.
Accordingly, by finding and excising the sentinel lymph node in a cancer removal surgery performed in the early stages of the disease, and preparing a sample of the excised sentinel lymph node and expediently performing a test for pathology thereon, it can be determined whether or not the cancer has metastasized to the lymph nodes.
For cases in which the cancer is determined not to have metastasized to the lymph nodes, it is unnecessary to remove the remaining lymph nodes. For cases in which the cancer is found to have metastasized to the lymph nodes, depending upon the conditions, a plurality of lymph nodes are surgically removed from the vicinity surrounding the diseased tissue.
By performing sentinel node navigation surgery, it becomes unnecessary to remove lymph nodes of patients for whom it has been determined that cancer has not metastasized to the sentinel lymph node, and the burden on such patients is thereby reduced. Moreover, this type of surgery is not limited to breast cancer, but can be employed in conjunction with open gastrointestinal tract surgery or surgical procedures utilizing a laparoscope.
One conventional method of detecting the lymph node is the colorant method, employing a blue colorant. According to this method, a blue colorant is locally injected, endermically or by use of an endoscope, into the vicinity surrounding the diseased area directly preceding the performance of cancer removal surgery; the sentinel lymph node dyed by the blue colorant is visually detected. Another known method is the RI method, wherein a radioisotope is employed as a tracer.
According to the RI method, a radioisotope is locally injected, endermically or by use of an endoscope, on the day prior to surgery into the vicinity surrounding the diseased area. The injected radioisotope advances from the position at which it was injected towards the lymph nodes and stays for a set duration at the sentinel lymph node. A few hours after the radioisotope is injected a lymphosynthography is performed, and the approximate position is marked. When the surgery to remove the cancer is performed, the marked position is cut open, and employing a gamma-probe, the gamma radiation emitted by the lymph nodes in the vicinity of the opened position is detected; the lymph node emitting the most gamma radiation is detected as the sentinel lymph node.
Further, in recent years fluorescent colorant methods employing fluorescent colorants have been proposed for detecting diseased tissue: For example, an embodiment of a sentinel lymph node detection apparatus has been disclosed in Japanese Patent Application No. 2000-124600, by the inventors of the present invention, wherein a cyanine colorant is administered to a living tissue, and by irradiation thereof by an excitation light, the diseased tissue is detected.
However, according to aforementioned conventional sentinel lymph node navigational surgery, when a determination is to be made as to whether or not cancer has metastasized to the sentinel lymph node, an on-the-spot diagnosis of the cause of the disease is performed by surgically removing the sentinel lymph node, preparing a sample thereof and examining an image of the cells contained in said sample. However, as per the case in which the early detection of breast cancer is performed as described above, for example, because the rate of metastasis of the disease to lymph nodes is 20 percent, for the 80 percent of the patients in whom the disease has not metastasized to the lymph nodes, the removal of the sentinel lymph node is unnecessary. Although there is a strong demand, accompanying the trend in recent years to preserve the QOL of the patient, for a sentinel lymph node detection method in which it is not necessary to surgically remove the sentinel lymph node, the conventional sentinel lymph node detection method and apparatus described above only disclose methods of lymph node detection, and there is no mention therein of a method or apparatus in wherein the test for pathology is performed in a manner in which the sentinel lymph node is not surgically removed.
SUMMARY OF THE INVENTION
The present invention has been developed in consideration of the circumstances described above, and it is a primary objective of the present invention to provide a sentinel lymph node optical tomographic image obtaining method and apparatus for obtaining an image of the cells of the sentinel lymph node for use in performing a test for pathology.
The method of obtaining an optical tomographic image of a sentinel lymph node according to the present invention comprises the steps of detecting the sentinel lymph node residing in the vicinity of a diseased tissue (hereinafter referred to as a target subject), scanning the detected sentinel lymph node with a signal-light having a coherence length of 5 um or less, and obtaining an ultra high resolution optical tomographic image of the sentinel lymph node by using the reflected-light reflected from a predetermined depth of said sentinel lymph node and the interference caused by the signal-light and a reference-light of a frequency slightly different from that of the signal-light.
Further, the method of detecting the sentinel lymph node can be based on a fluorescent-light image obtained of the fluorescent light, which is close to the near-infrared wavelength band, emitted from near-infrared fluorescent colorant that has been injected into an examination area of the target subject
Fuji Photo Film Co. , Ltd.
Shaw Shawna J.
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