Lymphoscintigraphy is now performed for detecting sentinel lymph nodes of malignant tumors [34]. However, we had performed this method for Bosutinib cell line detecting and diagnosing metastatic lymph nodes from malignant tumors of the head and neck [9], [10] and [11]. For the purpose of those, we used two kinds of agents: 99m-Tc-Re and 99m-Tc-HSA-D. Between 99m-Tc-Re and 99m-Tc-HSA-D, there is a difference in the mechanism of uptake because these two agents are composed of different components [9], [23] and [24]. In this article, we re-evaluated retrospectively the usefulness of lymphoscintigraphy with 99m-Tc-Re and 99m-Tc-HSA-D

and compared the results each other. We carried out two types of scintigraphies: a dynamic and astatic lymphoscintigraphy. In dynamic

lymphoscintigraphy, this website both 99m-Tc-Re and 99m-Tc-HSA-D showed no false negative, but showed false positive. This result might depend on the fact that lymphatic drainages easily changed even if the pathology of lymph nodes was benign or malignant, and usually showed variable pattern. Sometime lymphatic drainages change even in normal conditions. The accuracy of diagnosis was 76% in 99m-Tc-Re and 64% in 99m-Tc-HSA-D respectively, but their specificities were not high. In static lymphoscintigraphy, the accuracy was 84% in 99m-Tc-Re and 71% 99m-Tc-HSA-D, but their specificities were as low as those dynamic scintigraphy. The low specificities might depend on the fact that lymph nodes might show changes in advance to metastasis, for example inflammatory effects from tumor tissues. Moreover, it might be a cause to the low specificity that it was impossible to let all lymph

nodes have one to one correspondence to each other between lymphoscintigraphy and pathologic examination. In comparison of 99m-Tc-Re with 99m-Tc-HSA-D, 99m-Tc-Re showed a slightly higher agreement with pathological findings than Tc-99m-HSA-D. Unfortunately, it is difficult now to find out a single lymph node metastasis or a micro metastasis. These results of our evaluation of dynamic and static lymphoscintigraphy might be a hint to solve problems. At the present see more time that 201-Tl, 99m-Tc-MIBI, 99m-Tc-Re and 99m-Tc-HSA-D become not to be used popularly in comparison with FDG-PET, we do not expect that our previous results are useful or helpful to the routine dental practice directly. However, FDG-PET is recently found to have a problem in diagnosis of malignant tumors, for example FDG-PET accumulates both in malignant tumors and inflammatory lesions. This is just the problem that we also tried to resolve until now. Therefore, we hope that even a small part of our results shown in this article could be a clue or hint for dentists to try to find out a solution of problem, if it is a very small help.