Technetium(99mTc) Human Serum Albumin Diethylenetriamine Pentaacetic Acid

Sentinel node biopsy (SNB) in breast cancer is a promising surgical technique that avoids unnecessary axillary lymph node dissection. To optimize lymphatic mapping with radiopharmaceuticals, mammary lymphoscintigraphy with 30-50 MBq of technetium-99m-diethylenetriamine pentaacetic acid human serum albumin (99mTc-HSAD), technetium-99m-human serum albumin (99mTc-HSA), or technetium-99m-tin colloid (99mTc-TC) were investigated in 69 cases of primary breast cancer. Dynamic early images were obtained during the first 30 or 40 minutes, and static delayed images were obtained 6 hours after tracer injection. Hot spots as sentinel lymph nodes (SLNs) appeared in 51 of 69 cases (74%): in early images in 27 cases and in delayed images in 24 cases. SLNs were visualized more frequently in 23 of the 26 cases (88%) treated with 99mTc-HSAD and in 21 of the 24 cases (88%) treated with 99mTc-HSA than in only 7 of the 19 cases (37%) treated with 99mTc-TC. In 26 of the 51 cases, SLNs were identified as faint spots in delayed images. There was a significant difference in the first appearance of SLNs on the lymphoscintiscan between 43 cases of dense breast parenchyma and 26 cases of fatty breast parenchyma. These results suggest that 99mTc-HSAD or 99mTc-HSA is acceptable for lymphatic mapping, but in cases which have faint spots in delayed images or fatty breast parenchyma, gamma probe-guided SNB may result in failure or misleading false-negative SLNs.

Abdominal images were obtained after the intravenous injection of 99mTc-HSA-D in 8 patients with protein-losing gastroenteropathy (PLG). Six neck images and 7 abdominal images were obtained in 11 patients with ischemic heart disease as a control study. We evaluated all the images with respect to visualization, initial appearance time, and movement of abnormal radioactivity. In 7 of 8 patients with PLG, abnormal radioactivity in the intestine appeared from 10 min to 4 hours after injection, and moved 6 hours after injection. In 6 of 7 abdominal images of control cases, slight activity was observed in the alimentary tract 6 hours or 24 hours after injection. The thyroid was not visualized in any of the 6 cases. In conclusion, if radioactivity in the alimentary tract was first observed 6 hours or later after injection, the diagnosis of PLG may be difficult by this method alone. It still may be necessary to perform the alpha 1-antitrypsin test for the correct diagnosis of PLG.