Does The Preparation And Utilization Of Tc-99m-Sulfur Colloid Affect The Outcomes Of Breast Lymphoscintigraphy?

The purpose of this study was to determine whether certain factors in the preparation and use of Tc-99m-sulfur colloid affected the number of sentinel lymph nodes (SLNs) detected during SLN mapping and during intraoperative SLN identification. The factors that were investigated included the use of a dry heat block versus a hot water bath to heat the Tc-99m-sulfur colloid bulk vial, amount of (TcOH4-)-Tc-99m added to form the sulfur colloid particles, time between the unit dose calibration and the injection of the dose, and breast quadrant in which the injection occurred. Methods: Data were collected retrospectively and quantitatively analyzed from images and reports of 488 patients with breast cancer who had undergone SLN mapping and intraoperative SLN identification from January 1, 2008, to June 30, 2011, inclusive. The dependent variables assessed were the number of SLNs visualized during lymphoscintigraphy, number of radioactive SLNs removed during surgery, and total number of lymph nodes removed intraoperatively. Results: There was no significant difference in outcomes when comparing the amount of (TcOH4-)-Tc-99m added during the preparation process to form the sulfur colloid particles, time between the unit dose calibration time and the time that the unit doses were injected, or location in the breast tissue in which the unit dose was administered. Initially, there were observed significant differences in outcomes when the heating methods used to prepare the Tc-99m-sulfur colloid were compared. When the increased number of patients who were administered a calibrated unit dose activity of 74 MBq in the group using a dry heat block preparation method was taken into account, however, the findings were not significant. Conclusion: The use of a dry heat block versus a hot water bath to heat the Tc-99m-sulfur colloid bulk vial, amount of (TcOH4-)-Tc-99m added to form sulfur colloid particles, time between the unit dose calibration and the injection of the dose, and breast quadrant in which the injection occurred do not affect the number of SLNs detected during SLN mapping and during intraoperative SLN identification.