Harmonization of the patient exposure record through the kerma incident in air

The aim of this work is to propose a solution to the Bonn call to action and to the need mentioned by the IAEA on radiation protection in medicine. The proposal to cove those needs is to use the incident air kerma as a harmonizing parameter for the recording of dose in all x-ray modalities, since it is the simplest exposure parameter. In fact, this parameter is already used in 2D modalities such as radiography, mammography and radiology intra-oral. This work describes how to use it in 3D modalities (such as CT scan, bean conical or orthopantomographs). For this we have found an arithmetic relationship that includes th geometric parameters of the equipment (such as the focus-detector distance) and a measure of incident kerma that can be taken during the acceptance test (without dummies). With these data the kerma is estimate incident on the skin of any patient, based on the value of -mAs and the perimeter of the irradiated area with an uncertainty less than 7%. Based on data from teams from al modalities, the reference levels for a pediatric patient or a head exam (diameter o 16 cm) would be, respectively, 5, 20 and 35 mGy for low dose procedures (dental or guided i radiotherapy), medium dose (CT) or high dose (high resolution on angiography). The incident kerma offer also a more patient-centered alternative to -CTDI or -DLP measures for control quality routine