SPECT/CT and a portable gamma-camera for image-guided laparoscopic sentinel node biopsy in testicular cancer

The purpose of this study was to evaluate the utility of SPECT/CT and real-time intraoperative imaging with a portable γ-camera for laparoscopic sentinel node (SN) localization in stage I testicular cancer.

Ten patients with clinical stage I testicular cancer were studied between November 2006 and November 2010. Their mean age was 37 y (range, 25-50 y). The primary tumors were situated on the right side in 5 patients and on the left side in 5. After a funicular block with 2% lidocaine, an average dose of 80 MBq (range, 59-98 MBq) of (99m)Tc-nanocolloid in a volume of 0.2 mL was injected into the testicular parenchyma. Shortly after injection, a 10-min dynamic study was performed, followed by the acquisition of static planar images at 15 min and 2 h. SPECT/CT was performed at 2 h. After image fusion, SNs were visualized, and their exact anatomic location was determined. The SPECT/CT images were displayed in the operation room to guide SN detection using a laparoscopic γ-ray probe and a portable γ-camera.

Lymphatic drainage to the retroperitoneum was seen in all patients. SPECT/CT identified interaortocaval or paracaval SNs in the 5 patients with right-sided tumors, one of whom had an additional SN adjacent to the testicular vessels. In all 5 patients with left-sided tumors, paraaortic SNs were visualized; a node along the testicular vessels was visualized in 2 of these 5. Twenty-six SNs were laparoscopically removed (range, 1-4 per patient). An SN contained metastases in 1 case. No recurrences developed in the 9 patients with a tumor-free SN during a median follow-up of 21 mo (range, 2-50 mo).

SPECT/CT enables accurate anatomic localization of retroperitoneal SNs in patients with testicular cancer, facilitating their laparoscopic retrieval. Real-time image guidance by a portable γ-camera improves intraoperative SN detection and appears to identify (20%) additional SNs.