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We evaluated a portable γ-camera for sentinel node identification during laparoscopic sentinel lymphadenectomy for prostate cancer. Methods: We analyzed the portable γ-camera for intraoperative sentinel node visualization in 55 patients after ^sup 99m^Tc injection, preoperative planar lymphoscintigraphy, and SPECT/CT. Results: Sixteen percent of 178 nodes seen on SPECT/CT could not be detected with the portable γ-camera. A seed pointer was useful for localizing sentinel nodes intraoperatively in 27% of patients. Seventeen additional sentinel nodes (2 tumor-positive nodes) were removed by monitoring after excision. The location of each sentinel node was significantly associated with the ability to detect it intraoperatively. Conclusion: Intraoperative imaging leads to excision of more radioactive nodes and can determine the residual radioactivity after excision. The use of a radioactive source as a pointer enables efficient identification of nodes in difficult locations (paraaortic nodes) and in patients with a high body mass index.
Key Words: prostatic neoplasms; sentinel lymph node biopsy; radionuclide imaging; gamma cameras
J Nucl Med 2011; 52:741-744
DOI: 10.2967/jnumed.110.085068
Sentinel lymphadenectomy for staging of prostate cancer has been validated by several authors (1-3). Detection of sentinel nodes has been optimized by performing preoperative sentinel node imaging, including planar lymphoscintigraphy and SPECT/CT (4,5). To further improve intraoperative detection, we introduced a portable 7-camera to guide laparoscopic localization of sentinel nodes in prostate cancer (6).
Portable γ-cameras have been developed to provide intraoperative radioguidance, and a recent application has been intraoperative identification of radioactive lymph nodes (7-10). In urologic malignancies, sentinel nodes could be visualized in 90% of the patients and the use of a pointer enabled exact localization of the hot nodes (6).
The goal of the current study was to establish the value of intraoperative sentinel node imaging with a portable 7-camera in patients with prostate cancer. We evaluated whether intraoperative detection rates improved by additional intraoperative imaging.
MATERIALS AND METHODS
At our institute, patients with intermediate-prognosis prostate cancer who elect to be treated with radiotherapy are offered a sentinel node biopsy to determine the therapeutic regimen (2). These patients are clinical stage T2b or higher or have a prostate-specific antigen (PSA) level above 10.0 ng/mL or a Gleason sum score of 6 or more.
Fifty-five patients with prostate cancer in whom preoperative lymphoscintigraphy had shown lymphatic drainage were...