body outlining using tc-99m filled flood source for lymphoscintigraphy imaging

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.