|Comments by the Italian Association of Radiation Protection, AIRP|
ICRP draft : Radiological Protection in Cone Beam Computed Tomography (CBCT)
The document received the attention of our community with positive judgments about the objective, the structure and the contents of the document. However, it was observed a lack of attention to the dental CBCT that, even if it is motivated in the text, is perceived somehow disappointing. It was appreciated the emphasis given in reiterating that optimization refers not only to whole-body exposures, but also to specific tissues in view of the recent consideration on tissue reactions.
1) A specific comment refers to paragraph 9.4.Diagnostic reference levels.
The first part:
appears not to take in full consideration the corresponding paragraph in the cited SEDENTEX (EC, 2012):
“6.3.2 Establishing Diagnostic Reference Levels -The UK’s Health Protection Agency have carried out a preliminary audit of DAP across 41 dental CBCT units and have proposed an achievable dose of 250 mGy cm2 for CBCT imaging appropriate for the placement of an upper first molar implant in a standard adult patient. It should be noted that large FOV units in the sample exceed this and the dose audit data had been normalised to an area corresponding to a 4cm x 4cm field of view at the isocentre of the equipment. It is for this reason that they have referred to this dose level as an “achievable dose” rather than a DRL. “
In particular, for what refers to the use of the concept “achievable dose” rather than DRL and to the explanation that the dose value of 250 mGy cm2 is defined for a 4 cm x 4 cm FOV.
2) Note that the Tables 7.1, 7.3, 7.4, 7.6 and 7.7 seem not explicitly cited in the text. Moreover there is a suggestion to insert a footnote in Table 7.3 to make explicit, in the effective dose simulation for catheter ablation, the use of weighting factors from ICRP 60 and from ICRP 103.