Terrestrial and extraterrestrial radioisotope research has been strongly dependent on the development of analytical methods which would enable to trace radioisotopes at low concentrations in subgram samples (e.g., in tree rings, ice cores, meteorites, etc.). Accelerator mass spectrometry (AMS) has become the most sensitive technique for ultralow-level analysis of long-lived radioisotopes, such as 14C, 10Be and 26Al. We review developments and applications carried out in the CENTA laboratory, and describe a recently installed fully equipped AMS line, designed for analysis of long-lived radioisotopes from tritium to curium.