|Comments regarding the ICRU/ICRP draft report about operational quantities in radiation protection|
Dear colleagues of RC 26,
I’m concerned about the long-term continuity of the new concept of measurement quantities. You propose the direct relationship of the operational quantities to the current voxel phantom representation of effective dose. ICRP is working hard to develop new hybrid computational phantoms. The new phantoms will be published and effective dose will be adapted accordingly. I propose the following approach to avoid future changes of the measurement quantities, at least as long as the effective dose concept is favoured by ICRP. A constant safety factor of 1.2 shall be applied to the simulated conversion coefficients. This means that operational dose quantities provide conservative estimates taking possible changes in effective dose up to 20 % into account. This factor will not increase the measurement uncertainty in terms of operational quantities. In most radiation protection situations the measurement uncertainty is anyway higher than 20 %. At the end it is not clear to me if there is a real change or benefit of the new quantities.