All of the tracers were sub-mucosally injected in four quadrants of the cervix at 0, 3, 6, and 9 o’clock. The cervical injection was about 5 mm in all cases, as described previously [20 (link)21 (link)]. On the day before the operation, 2.0 mL of fluid containing 110 MBq 99m-technetium (99mTc)-labeled tin colloids was injected into the patient’s cervix. Lymphoscintigraphy was performed within 6 hours, and hot spots, indicating SLNs, were identified. On the day of the operation, 5 mL of indigocarmine (IDC) (4 mg/mL) and/or indocyanine green (ICG) (50 µg/mL) was injected into the cervix at the start of surgery. SLN was detected at 40 minutes after injection of IDC or ICG. Radioactive lymph nodes were located using a gamma-probe (Navigator GPS; RMD Instruments Inc., Watertown, MA, USA). IDC-stained lymph nodes were detected by direct inspection. ICG fluorescence-positive lymph nodes were detected using a color fluorescence camera (Hyper Eye Medical System; MIZUHO Medical Co., Ltd., Tokyo, Japan, for laparotomy; Camera Control Unit JC300; MC Medical Co., Tokyo, Japan, for laparoscopy). After SLN biopsy, the area of pelvic lymph node was surveyed by direct observation, and with a color fluorescence camera or a gamma-probe to confirm that no radioactive tissue remained. The combination of 99mTc and IDC was used in early phase and combination of three tracers were used in late phase.