Synthesis of the European ALARA network 20th workshop 'ALARA for interventional radiology and nuclear medicine'.

The European as low as reasonably achievable(ALARA) network regularly organises workshops on topical issues in radiation protection (RP). The topic of the 20th workshop was: 'ALARA for interventional radiology (IR) and nuclear medicine (NM)'. The objective was to examine the challenges faced when applying the optimisation principle (ALARA) in IR and NM and to consider how ALARA could be better implemented for patient and staff exposures. This memorandum provides a synthesis of the workshop sessions, and recommendations coming from the working groups discussion. Parallels are drawn with the recommendations arising from the 13th EAN workshop on 'ALARA and the medical sector (2011)' to consider how the optimisation challenges in IR and NM have evolved over the past decade. Current levels of exposure are presented along with operational practice and the challenges and opportunities for improvement, both in monitoring and practice. Whilst RP challenges remain, the application of ALARA appears more established in IR compared with experiences reported in 2011. The application of ALARA to emerging technologies in the NM setting is in need of further development to ensure that RP is considered at all stages in the development process of new radiopharmaceuticals. Besides the obvious technical and operational aspects, the importance of education and training, human factors and broadly the RP 'culture' were deemed fundamental to the success of the application of ALARA and where further emphasis is needed. All concerned parties, medical physics experts (MPEs), radiation protection experts, clinical staff, manufacturers and regulators have a role to play in the application of ALARA and this is discussed in the memorandum. Many of the recommendations from the 13th EAN workshop remain applicable today and overlap with the recommendations arising from the 20th workshop. This should prompt attention given that the use of IR and the development of novel radiopharmaceuticals for NM is only anticipated to increase with time.

Advancements in NORM metrology - Results and impact of the European joint research project MetroNORM.

The results of the three years European Metrology Research Programme's (EMRP) joint research project 'Metrology for processing materials with high natural radioactivity' (MetroNORM) are presented. In this project, metrologically sound novel instruments and procedures for laboratory and in-situ NORM activity measurements have been developed. Additionally, standard reference materials and sources for traceable calibration and improved decay data of natural radionuclides have been established.

Study of particular problems appearing in NORM samples and recommendations for best practice gamma-ray spectrometry.

In this paper spectral interference effects for selected gamma-emitting radionuclides of the natural decay series and 40K in selected NORM samples are studied. Recommendations for the choice of γ-lines and the consideration of possible spectral interferences are provided. Special attention is given to the radon tightness of the sample containers. A simple and sensitive method for the estimation of the 222Rn leakage of sample containers is introduced. The applied polystyrene sample containers show 222Rn leakages lower than 1%.

Study of parameters relevant for a better prediction of the radon potential.

In 2012 and 2013 measurements of parameters relevant for a better prediction of the radon potential were carried out in Austria at 100 sites. The parameters were the (222)Rn activity concentration in soil gas, the soil's permeability, the ambient equivalent dose rate above the ground and the soil's massic activity by gamma spectrometry. The uncertainties of sampling and measurements are discussed as well as the correlations between these parameters.

Radon soil gas measurements in a geological versatile region as basis to improve the prediction of areas with a high radon potential.

With the aim to predict the radon potential by geological data, radon soil gas measurements were made in a selected region in Styria, Austria. This region is characterised by mean indoor radon potentials of 130-280 Bq m(-3) and a high geological diversity. The distribution of the individual measuring sites was selected on the basis of geological aspects and the distribution of area settlements. In this work, the radon soil gas activity concentration and the soil permeability were measured at 100 sites, each with three single measurements. Furthermore, the local dose rate was determined and soil samples were taken at each site to determine the activity concentration of natural radionuclides. During two investigation periods, long-term soil gas radon measurements were made to study the time dependency of the radon activity concentration. All the results will be compared and investigated for correlation among each other to improve the prediction of areas with high radon potential.