11. tbl. 103. árg. 2017

Effective dose from pediatric CT in Iceland

Geislaálag barna í tölvusneiðmyndum á Íslandi

Introduction: It is important to know the effective dose from computed tomography (CT) examinations. The aim of this study was to evaluate the effective dose from pediatric CT examinations in Iceland.

Materials and method: For all pediatric CT exams (children < 18 years) performed during one year (1.2.2016 till 1.2.2017), data on age, examination type and dose length product was retrospectively collected from the Landspitali University Hospital's archives, as was the total number of CT examinations. The ratio of pediatric CT exams and the frequency of examination types were calculated and, for the three most common examinations, the effective dose and mean dose length product were calculated for five age groups.

Results: The total number of pediatric CT examinations was 662, 3,6% of all the CT examinations performed. The three most common pediatric CT examinations were head (40,3%), abdomen (15,6%) and thorax (10,3%). The mean effective dose in those was, in the above order: for children < 4 months: 5,3/4,9/3,0 mSv; 4 months to < 3 years: 4,2/5,5/1,9 mSv; 3 years to < 8 years: 2,7/ 3,4/1,0 mSv; 8 years to < 15 years: 3,2/4,4/1,0 mSv and 15 years to < 18 years: 2,1/6,5/3,3 mSv. The mean dose length product was above European diagnostic reference levels in most examination types and age groups.

Conclusion: Possibilities for lower effective doses from pediatric CT examinations should be explored. For that purpose, the use of size specific dose estimates is recommended.

Table I: Number of examinations and mean dose length product (DLP) for five different age groups in the three most common pediatric computed tomography (CT) examinations at Landspitali University Hospital.  The mean is compared to the European diagnostic reference levels for pediatric imaging (PiDRL) (8).

Table II: Mean effective dose in the three most common pediatric computed tomography (CT) examinations, calculated with conversion factors from AAPM (9) for five different age groups as well as mean and range of dose length product (DLP) for each age group.

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