Evaluation in the baboon model of (99m)Tc-biguanide as a tracer for renal imaging.

Studies in various animal species have recently shown that (99m)Tc-BIG has practical and dosimetric benefits for renal imaging that could probably make it a good alternative to (99m)Tc-2, 3-dimercaptosuccinic acid ((99m)Tc-DMSA). In this study, using the baboon experimental model, the biodistribution of (99m)Tc-BIG and (99m)Tc-DMSA are compared. It is demonstrated that early good contrast imaging and more favourable dosimetry is possible with (99m)Tc-BIG compared to (99m)Tc-DMSA, confirming the quoted previous findings with small animals. Time-activity curves for kidneys and other organs support these findings, and MIRDOSE software provided the dosimetry.

Synthesis, characterization, and biodistribution of oxo complexes of technetium-99m with biguanide and N1-substituted ligands.

We report the synthesis, characterization, and biodistribution of 99mTc-complexes with the bidentate-N,N chelate biguanide (Big) and the N1-substituted ligands dimethyl (DMBig), phenyl (PBig), and phenethyl (PEBig). Dynamic gamma-camera studies with 99mTc-Big and 99mTc-DMSA in rabbits indicated distinct renal and urinary excretion profiles. 99mTc-Big was cleared more quickly than 99mTc-DMSA, and for the same acquisition times, the contrast in whole-body images favored 99mTc-Big. Also, the estimated radiation absorbed doses by kidneys and blood for 99mTc-DMSA were significantly higher than for 99mTc-Big. These preliminary studies show that 99mTc-Big has favourable practical and dosimetric features for renal imaging as an alternative to 99mTc-DMSA.

Nuclear medicine and mathematics.

The purpose of this review is not to present a comprehensive description of all the mathematical tools used in nuclear medicine, but to emphasize the importance of the mathematical method in nuclear medicine and to elucidate some of the mathematical concepts currently used. We can distinguish three different areas in which mathematical support has been offered to nuclear medicine: physiology, methodology and data processing. Nevertheless, the boundaries between these areas can be indistinct. It is impossible in a single article to give even an idea of the extent and complexity of the procedures currently used in nuclear medicine, such as image processing, reconstruction from projections and artificial intelligence. These disciplines do not belong to nuclear medicine: they are already branches of engineering, and my interest will reside simply in revealing a little of the elegance and the fantastic potential of these new "allies" of nuclear medicine. In this review the mathematics of physiological interpretation and methodology are considered together in the same section. General aspects of data-processing methods, including image processing and artificial intelligence, are briefly analysed. The mathematical tools that are most often used to assist the interpretation of biological phenomena in nuclear medicine are considered; these include convolution and deconvolution methods, Fourier analysis, factorial analysis and neural networking.