%0 Journal Article %A Gabrielle Smith %A Andrew Thrams %A Ann Voslar %T Impact of metastatic disease on transit time in sentinel node lymphoscintigraphy. %D 2021 %J Journal of Nuclear Medicine %P 159-159 %V 62 %N supplement 1 %X 159Objectives: Lymphoscintigraphy is a Nuclear Medicine procedure utilized to locate the sentinel lymph node prior to surgical intervention. The purpose of this study is to determine if there is a correlation between lymphatic system transit time and sentinel node carcinoma positivity rate. Methods: Patients were selected at random from a population over a nine-month period. All the patients underwent a breast or melanoma lymphoscintigraphy study using Tc-99m sulfur colloid the day of, or the day prior to surgery. The post procedural surgical pathology report was utilized to determine sentinel node pathology. Other information collected and compared in this study are: injection location, injection quantity, sulfur colloid filtration, and injecting physician. Lymphatic transit time was determined from the time of injection until node visibility on the dynamic or static images. Results: Fifty-seven patients’ studies were reviewed. Of these, 8 sentinel lymph nodes were positive and 49 were negative for carcinoma. The average transit time was 32.9 (±12.7) minutes for positive lymph nodes, and 16.0 (±34.6) minutes for negative lymph nodes. A t-test calculation determined on a 95% confidence interval a p-value of 0.00003 indicating the data is significantly different. Comparing breast and melanoma lymphoscintigraphy, a p-value of 0.54 was calculated. Additionally, when comparing filtered and unfiltered sulfur colloid a p-value of 0.68 was determined. The location and filtration of sulfur colloid p-values were not significantly different. Conclusions: In conclusion, the average lymphatic system transit time of positive nodes was significantly different than that of negative nodes. However, several other factors could affect the results. These include injection location, injection quantity, sulfur colloid filtration and depth of injections. Therefore, the data cannot conclude whether the transit time directly correlates with the diagnosis of a positive sentinel lymph node. The transit time of the tracer during lymphoscintigraphy does not determine the diagnosis of the sentinel node and should not be used as an indicator of the potential spread of carcinoma. %U