Contribution of Mass Resolution to Secondary Ion Mass Spectrometry Microscopy Imaging in Biological Microanalysis

Abstract

This paper presents recent developments in nuclear medical applications of secondary ion mass spectrometry (SIMS) microscopy. This technique is the only method (with laser microprobe mass spectrometry) potentially able to map all the elements of the periodic table, including stable and radioactive isotopes. We have demonstrated with our microscope (lateral resolution 0.5 µm; mass resolution 300–10 000) that this imaging technique can localize radioligand biodistributions on tissue sections if a mass resolution above 2000 is used. We chose three radioactive isotopes: technetium-99 m (^99mTc), strontium-89 (⁸⁹Sr) and bromine-76 (⁷⁶Br). The ^99mTc is introduced into the cell by a lipophilic ligand. The ⁸⁹Sr is metabolised and integrated into bone matrix because it is a calcium analog. The ⁷⁶Br targets adrenals because it is bound to a ligand which has chemical analogies with endogenous bioamines. Our data confirm and extend to other models the suggestion that SIMS should constitute a pertinent approach to cellular dosimetries.