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Into the Future with Metrology - The Challenges of Medical Technology

Diagnostics and Therapy

It's the dose that counts

Percentage of the different types of X-ray examinations
Percentage of the different types of X-ray examinations contributing to the total frequency and to the collective effective dose in Germany for 2014 (Source: BMU/BfS: Environmental radioactivity and radiation exposure in 2016).

Around 140 million X-ray examinations are carried out in Germany every year; thus, X-rays account for about 40 % of the total effective dose per year received by the population exposed to ionizing radiation from natural and man-induced radiation. Hence, dosimetry is important for quality assurance in X-ray diagnostics, and it is also important to fulfill the requirement to achieve sufficient imaging quality with a minimum radiation dose. PTB plays a very important role for technical quality assurance in X-ray diagnostics where it realizes the basic dosimetric quantity – the air kerma. PTB operates numerous reference radiation sources for calibrations and tests in conventional X-ray diagnostics, computed tomography and, especially, mammography. An important customer for PTB is the International Atomic Energy Agency (IAEA) with its worldwide network of secondary standard laboratories. More than 80 countries are involved in this network. By statutory mandate, PTB tests diagnostic dosimeters which are used for acceptance and constancy tests of medical X-ray diagnostic equipment for examinations on humans and are subject to the German Measures and Verification Act. For this purpose, PTB carries out type examinations in accordance with the Measures and Verification Ordinance, so that dose measurements are reliable in practice and patients are protected in the best possible way. PTB participates – in a leading function – in the elaboration of relevant international and national standards, for example, standards which define reference radiations or specify requirements for dosimeters. PTB's research focuses on dose-intensive procedures such as computed tomography, which is used in 8 % of all X-ray diagnostic examinations, but accounts for 64 % of the collective effective dose (see figures). For example, PTB is developing a modern and fast method of personalized CT dosimetry. Its aim is to adapt the imaging parameters to the individual patient by precisely knowing the patient- and scanner-specific CT dose in order to reduce that dose.


Department involved
Opens internal link in current window6.2 Dosimetry for Radiation Therapy and Diagnostic Radiology