A 32 year-old woman with a history of T2-N1 left breast cancer, diagnosed 2 years ago and treated with mastectomy-immediate reconstruction, presented with a right axillary lymphadenopathy. Upon clinical exam, the lesion was non-palpable and measured approximately 1 cm by US. The lymphadenopathy persisted on a follow-up; FDG-PET imaging was negative. An US-guided FNA was non-definitive without evidence of malignancy. An increase in size of the node was noted at the subsequent follow-up. A clinical decision was made for an excision biopsy. The node was injected with Tc-99m macroaggregate albumen (MAA) and lymphazurin blue 2 h prior to the planned operation. At surgery, the hot-spot was readily identified. Probe localization was distinctly focal over a level-I node, which was accessed with minimal dissection. Blue dye facilitated surgical exposure and dissection. Surgical pathology revealed chronic inflammatory changes (Figure 1).

A 65 year-old woman with history of colorectal cancer (CRC) and non-Hodgkin's lymphoma of the scalp, presented with mediastinal and retroclavicular lymphadenopathy. CRC was diagnosed 2 years ago, and was treated with R-colon resection. Scalp lymphoma was diagnosed 6 months ago, when the patient presented with a 15 cm scalp lesion. Staging work-up at that time revealed positive FDG uptake in the scalp lesion (SUV:18), multiple mediastinal and R-retroclavicular lymph node (SUV:3.2), and a 12 cm liver lesion (SUV: 8.5). Biopsy of the liver lesion was consistent with the colon primary. Nodal findings were concluded to indicate a stage III lymphoma, and a sequential intensity-modulated radiation therapy (IMRT) and chemotherapy using CHOP regimen was administered. There was a complete clinical and FDG-PET/CT response in the scalp lesion. Post-treatment FDG-PET/CT showed persistence of mediastinal and R-retroclavicular nodal uptake. The R-retroclavicular node was injected with Tc-99m MAA and lymphazurin blue 2 h prior to the planned operation. At surgery, the hot-spot was readily identified. Probe localization was distinctly focal over an internal jugular-innominate vein confluence lymph node. The target was accessed through an incision made over the hot-spot. The line-of-sight provided a safe surgical dissection. The blue dye facilitated surgical exposure and dissection. Surgical pathology revealed a chronic granulomatous disease. The patient was restaged to have a stage I scalp lymphoma, and remained in complete remission following treatment. Stage IV CRC was also concluded to be a liver-only disease, which allowed her to be considered for liver-directed therapy (Figure 2).

A 69 year-old man presented with anemia, subsequent colonoscopy revealed a right colon cancer and multiple polyps throughout the colon. Severe dysplastic changes were noted in a sessile polyp in the transverse colon and in a pedunculated polyp in the sigmoid colon of villous type. The descending colon polyp was completely excised colonoscopically and the site was submucosally injected with Tc-99m MAA and lymphazurin blue 18 h prior to a planned operation. At surgery, the ascending colon lesion was readily identified. None of the polyps were palpable. A slight, relatively diffuse discoloration of submucosal blue dye was noted at the site of injection. Probe localization was distinctly focal. A total abdominal colectomy was performed with 2-cm margins distal to the focal Tc-99m MAA signal. Surgical pathology confirmed complete resection with free margins (Figure 3).

The patients receive an injection of 0.1 mCi (0.037 MBq) (in 0.1 ml solution) Tc-99m MAA the morning of planned surgery. Lymph node injections are given most conveniently under US. For colon polyp localization, the injection using the same activity and volume is given endoscopically. Surgical exploration is scheduled within 6 hours post injection of the radiopharmaceutical. The injected activity might be doubled if surgery is planned 6–12 hours after the injection (Table 1). Standard gamma probe settings (photopeak of 140 keV, Window of 20%, and a threshold of 136 keV) and operative technique are used in the operating room.