**1. Introduction**

A dosimetric procedure aims to estimate a quantity to guarantee the delivery of the correct prescribed dose to a patient or the dose resulting from a diagnostic procedure.

To achieve this purpose, one must ensure that:


• the clinical results of different institutions can be comparable if the air Kerma or absorbed dose, in addition to the biological clinical parameters, is well known and fully described.

To fulfill those premises, the radiation detectors must be calibrated following a universal protocol agreed among the professional societies, and the quantities referenced to the standards at the BIPM as it was decided by the Metro Convention. The dissemination of these quantities until the final user is done through the calibration laboratory in each country either national or secondary following a logical chain of events as described in **Figure 1**.

At this point, one must highlight the importance of a network called: International Metrological Network, which fundamentally seeks to standardize the processes and the methodologies among the various laboratories in the world. As a result, the measurement of the main quantities of interest in radiotherapy, radiology, and radioprotection such as air Kerma and absorbed dose to water allows the clinical results and the biological effects to be compared scientifically among different users, with an acceptable level of uncertainties for each area.

#### **Figure 1.**

*The main steps involved in the implementation of the quantities: (a) air kerma and (b) absorbed dose to water.*

#### **Figure 2.**

*The international network of ionizing radiation metrology showing the traceability process between the primary standards coordinated by the BIPM followed by the network of the secondary laboratories traceable to the IAEA Laboratories, the BIPM or any other primary laboratory and the final user [1, 2].*

The two steps shown above in **Figure 1** constitute a simplification of the various levels of complexity that represent the metrological chain, and the algorithms used now are best illustrated now in **Figure 2**.
