LYMPHOSCINTIGRAPHIC IDENTIFICATION OF SENTINEL LYMPH-NODES - CLINICAL-EVALUATION OF 0.22-MU-M FILTRATION OF TC-99M SULFUR COLLOID

PURPOSE: To evaluate the use of 0.22-mu m filtration of technetium-99m sulfur colloid particles in the optimization of lymphoscintigraphy. M ATERIALS AND METHODS: Forty-one consecutive lymphoscintigraphic studie s obtained with 0.22-mu m filtration of Tc-99m sulfur colloid in 41 pa tients (26 men, 15 women; average age, 55.4 years) and 41 consecutive studies obtained with 5.0-mu m filtration in 41 patients (20 men, 21 w omen; average age, 54.5 years) were retrospectively, randomly reviewed . Studies were evaluated for lymphatic channel depiction and sentinel lymph node depiction. Studies included immediate flow images (obtained at 10 seconds per frame) and multiview static images obtained up to 2 hours after intradermal Tc-99m sulfur colloid injection. RESULTS: The number of drainage beds visualized was 52 with 5.0-mu m filtration an d 51 with 0.22-mu m filtration (P = .570). The number of lymphatic cha nnels visualized was 45 with 5.0-mu m filtration and 75 with 0.22-mu m filtration (P = .006). The number of lymph nodes visualized was 102 w ith 5.0-mu m filtration and 123 with 0.22-mu m filtration (P = .123). The number of studies judged as optimal (ie, depicted lymphatic channe ls leading to sentinel nodes) was 10 with 5.0-mu m filtration and 19 w ith 0.22-mu m filtration (P = .038). The number of studies with depict ed lymph nodes but no depicted lymphatic channel was 15 with 5.0-mu m filtration and six with 0.22-mu m filtration (P = .023). CONCLUSION: T he use of 0.22-mu m filtration in the preparation of Tc-99m sulfur col loid substantially improves study quality and increases the diagnostic certainty in the identification of sentinel lymph nodes.