Mehdi Momennezhad - Nuclear Medicine Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
Hamid Reza Haghighi Kakhki - Azad University of Medical Sciences, Mashhad, Iran
Ramin Sadeghi - Nuclear Medicine Research Center, Mashhad University of Medical Sciences, Mashhad, Iran

  Introduction: In the current study, we evaluated the feasibility of body outlining using Tc-99m filled flood source for lymphoscintigraphy imaging. Methods: 80 patients were included in the study. Sentinel node mapping was done using Tc-99m Antimony sulfide colloid. For outlining the body a Tc-99m filled flood source was used which was placed behind or lateral to the patients for Anterior and lateral images respectively. The flood source was filled with 0.5 mCi, 1 mCi, 2 mCi, and 5 mCi for 10, 47, 10, and 3 patients respectively. The quality of outline images was assessed by two nuclear medicine specialists independently. Radiation exposure to the patients was also evaluated using thermoluminescent dosimeter (TLD-100).   Results: The quality of body contour images were good in images taken by 1, 2, and 5 mCi filled flood source. However the quality of images was poor in 8 out of 10 lymphoscintigraphies taken by 0.5 mCi filled flood source. The measured dose rate from the Tc-99m flood source was 1.07 ± 0.04 µSv/MBq/hr (39 ± 1.5 µSv/mCi/hr) or 3.25 µSv for 5 min acquisition times. Conclusion: Body outlining is feasible with Tc-99m filled flood source. To assure high quality, at least 1 mCi of Tc-99m pertechnetate should be used for filling the source. This technique can be very useful especially when Co-57 is not available or has decayed. The need to prepare the flood source for each patient and difficulty in handling the source especially for the lateral views are the major limitations.

Sentinel node, Tc-99m-Antimony sulfide colloid, Lymphoscintigraphy, Body outlining, Flood source