Publisher Summary This chapter provides an introduction to intecalibration/analytical quality control and doses. The purpose of the analytical quality control programmes was to assist laboratories engaged in the analysis of samples of environmental origin for radionuclide determination and to check the quality of their work. Such control is necessary as results of analytical activities may be the basis upon which economic, administrative, legal or medical decisions are taken; they must, therefore, be documented to be sufficiently reliable. Reliability of results is a function of precision (reproducibility) and of accuracy (true value). The precision of results can easily be determined by internal measures. Measurement of the actual concentration of radioactivity in man is the only true tool for estimating the real dose received. The results can then be compared with different models and estimations. A calibration of whole-body measurement was performed by sending “phantoms” simulating the human body and containing known activities of 134Cs and 137Cs around the Nordic countries.