HC13 aggregated data for head,
chest,
and abdomen-pelvis exams from all of the provinces and territories in Canada.
In order to have a provincial DRL breakdown,
a literature review of PubMed and MEDLINE databases was conducted.
The search was limited to include literature from 2007 to Current.
Upon completion,
eight articles from six provinces were deemed acceptable for inclusion in this environmental scan.
The 75th percentile provincial DRL data for single—phase,
non-contrast head,
chest,
and abdomen-pelvis exams was obtained in the literature and compared to the government standard,
HC13.
These results are in Table 1.
The goal was to only compare plain,
single-phase studies with no contrast to each other,
but it was unfortunately not possible and are subsequently identified.
To allow for international comparison,
data from the United Kingdom (UK11) [8] and the United States of America (US14) [9] were included as well,
due to their length (first published DRLs in 1991) and size (1,310,727 exams),
respectively.
These comparisons are visible in Table 2.
CT Head: As displayed in Figure 1,
three provincial results - BC13,
MB10,
and SK08 - are above HC13 guidelines.
SK08 was well above the acceptable range at 1,478 mGy·cm.
The explanation for this is due to a change in protocol for higher quality images,
resulting in an increased dose [11].
CT Chest: As shown in Figure 2,
four provinces (5 studies) - BC13,
SK06,
SK10,
MB10,
and ON13 - surpassed the guideline given by HC13.
Protocol variations between sites and multidetector scanners are likely culprits for the increased doses [13].
CT Abdomen/Pelvis: As exhibited in Figure 3,
SK06,
SK08,
and MB10,
for a total of two provinces,
had DRLs that surpassed the HC13 guideline.
While SK08 was higher than SK06,
they did note that a reduction in single-phase abdomen-pelvis CT doses was present [11].