The Federal Ministry for Environment, Nature Conservation, Building and Nuclear Safety would like to comment on the following two points regarding the proposed report “Diagnostic Reference Levels in Medical Imaging”.
1.) Chapter 2 (bullet 9) “75th percentile”
The 75th-percentile-concept is not an appropriate instrument to establish and evaluate DRLs in nuclear medicine in Germany because until now the DRLs were set based on the median. In this case the value would lead to higher DRLs (e.g.: present DRL for thyroid diagnosis with 99mTc-pertechnetate = 70MBq; median value ≈ 70MBq but 75th percentile ≈ 75MBq).
2.) Chapter 7 (bullet 6) “consistently exceeded”
“Consistently exceeded” means that the DRL value is exceeded for more than one time – otherwise (one exceedance) the DRL is “exceeded”. I think after one exceedance the reason for this should be investigated. After consistent exceedance then further measures have to be taken.