Dear Sirs,
This is an excellent document but clarity may be needed over the examples of justification and optimisation. The following statement is included under optimisation whereas the choice of modality is correctly an issue of justification.
1694 5.3. Optimisation and reporting of doses
1695 Choice of technique
1696 (102) Patient imaging procedures typically involve partial body radiation exposures, and
1697 exposure of tissues with differing sensitivities in terms of radiation-associated cancer risk.
1698 The amount of radiation and its distribution within the tissues of the body can be very
1699 different with different imaging modalities, even when a similar region of the body is being
1700 imaged. Since dose distributions from machine-produced x-ray and nuclear medicine
1701 procedures are very different, the effective dose is suitable for use in straightforward
1702 comparisons of doses from different techniques.
1703 (103) When two different x-ray imaging modalities are considered, comparison of effective
1704 dose can be of value in guiding a referral test selection. For example, a chest CT examination
1705 and a conventional chest x-ray both irradiate the lungs, but the effective dose from CT can be
1706 a few hundred times that of chest radiography, depending on the protocol technique...