Descrição: After decades of research and improvements, ICRU recognizes that the system of quantities and units, designed to measure ionizing radiation, ”fallen short of perfection due to compromises among the unavoidable ambiguities inherent in the real natural world and the need nonetheless for a basic set of useful quantities”. The difficulties stem from the complexity of the phenomena that occur in the interaction of ionizing radiation with matter. Due to these problems, difficulties for definition and dissemination of quantities and units used in radiation protection are evident and some criticism has been presented. In the radiological protection system currently recommended for situations of the radiation exposure, it must be calculated, taking into account the available data, the equivalent dose and effective dose values - immeasurable quantities used only for the purpose of limitation. On the other hand, measurements must be performed by dosimeters calibrated in operational quantities (dose equivalents). This duality of quantities encompasses a number of scientific and philosophical problems, which we discuss in our paper. We argue that excessive quantities and units proposed over time causes confusion in their applications. The commitment between scientific rigor and the need for convenience of concepts and procedures to be implemented makes the metrology of ionizing radiation (in particular, radiological protection) a suitable domain for questioning some very deep epistemological beliefs. |