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Sentinel Lymph Node Detection

illustrationWhen certain cancer is diagnosed (mainly breast cancer), the patient must often undergo lymph node dissection to check for the spread of cancer. In the case of breast cancer, removing lymph nodes often results in lymphedema (chronic swelling) of the arm. The Sentinel Lymph Node (SLN) biopsy is a new diagnostic procedure used that only removes the sentinel nodes (the first lymph node to receive drainage from the tumor site). If the sentinel nodes do not contain tumor (cancer) cells, this may eliminate the need to remove additional lymph nodes.

Before entering the operating room, the surgeon injects a small dose of a low-level radioactive tracer in the region of the patient’s tumor along with a blue dye which helps visually trace the location of the sentinel node. A few hours later the surgeon uses a gamma probe to guide him/her in finding the sentinel lymph node. The gamma probe detects the radioactivity of the tracer and signals the surgeon as he gets closer to the sentinel lymph node. Once the sentinel lymph node is detected, it is removed and the biopsy is performed.

Laparoscopic Surgery

For localization of lesions in the abdomen, a long and narrow gamma probe is required in order to fit through the trocar. Generally laparoscopic probes have a diameter at the tip of 10 mm and a total length of 400 mm. The tip of the probe is designed to "look" sideways in an angle of 45 or 90 degrees. For example the uterus is approached from the side and a straight forward pointing window of detection would not apply.

The laparoscopic probe is also effective with endoscopic surgery, at deep-set lymph nodes, minimally invasive surgery, lymph nodes in Cervical and Prostate cancer. Lately there is also research done on the presence of lymph nodes behind the sternum or in the lung area.

Thoracic Surgery

Thoracic surgery is the field of medicine involved in the surgical treatment of diseases affecting organs in the thorax (the chest). There has been a growing interest in applying the SLN detection concept to the Thoracic Region where intercostal lymph nodes are located. The patient’s tumor site is injected with a low-level radioactive tracer which drains though the lymphatic system. A gamma probe with a small diameter of <10 mm is then used to guide the surgeon to the sentinel lymph node. Once the sentinel lymph node is located is it removed and biopsy is performed.

The same type of small diameter gamma probe is also used by thoracic surgeons for biopsies of sub-centimeter lung nodules labeled with Technetium and previously identified by standard methodologies.

Radioactive Seed Localization

Radioactive seeds are used in place of wire localization for pinpointing tumors during breast cancer surgery. This new procedure involves implanting radioactive pellets the size of a grain of rice into the affected area of the breast. Surgeons then pinpoint the tumor using the Crystal Probe. This procedure guides the surgeon to the precise location to make the incision so the cancer and radioactive seed can be removed.

Using a high quality probe like the Crystal Probe is essential in locating the radioactive seed. If the surgical probe misleads the surgeon he/she will have difficulty finding the radioactive seed and then may proceed to make the incision in the wrong location. is a division of Nuclear Fields USA Corp.
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