208 H . Sekkat et al .: Radioprotection 2024 , 59 ( 3 ), 203 – 210
Fig . 5 . Comparative analysis of Deff across age groups in our study and ICRU 74 .
density in male patients . Importantly , Dw consistently surpasses Deff concerning age , implying a smaller conversion factor for Dw as patients age . Consequently , SSDE calculations using Dw result in lower radiation doses compared to Deff , with an average difference of 4.3 % for females and 9.1 % for males . This highlights the significance of understanding Dw calculations for precise SSDE determination in pediatric head CT scans , given the substantial difference between Dw and Deff , primarily attributed to the presence of bone and soft tissue .
Comparison with the ICRU 74 report ( ICRU , 2005 ) reveals consistently smaller Deff values in our study , particularly notable in the 1 – 5 yr age range . This discrepancy is attributed to differences in sample populations , with ICRU 74 utilizing hermaphrodite mathematical phantoms from Europe , while our study sampled patients from the North African region , emphasizing the necessity for tailored pediatric CT protocols in North Africa , particularly in Morocco . Despite the study ’ s insights , a limitation lies in the relatively small sample size from a specific pediatric hospital in one region , warranting further work with a larger and more diverse population , also the method used for measuring patient ’ s head dimensions ( LAT and AP ) which relies on the central slice with longest diameter , the use of this method isdueto the lack ofacustomized method for thistype of measurements in the context of pediatric head , warranting future research to establish it . Additionally , considerations for variables like the correlation between Dw , BMI , and patient body weight should be explored .
It ’ s imperative to acknowledge substantial variations in head dimensions at a given age , particularly during infancy . Therefore , for accurate patient dose estimation , calculated patient sizes ( Deff or Dw ) from patient images , whether from CT
radiographs or cross-sectional CT scans , are considered more reliable . Patient age serves as an approximation and is only employed when size information from the images is unavailable .
The current work examines the variation in head size among young patients undergoing CT scans , with an emphasis on the consequences for managing radiation exposure . It is acknowledged that there is a lack of defined measuring techniques in pediatric CT scans , underlining the need for additional research to establish guidelines . Comparisons with ICRU guidelines provide information on how well this study ’ s results match accepted standards . Furthermore , the observation regarding the relative stability of head size measurements across different slices compared to other anatomical regions as chest ( Boos et al ., 2018 ) highlights the importance of customized measurement methodologies in pediatric radiology .
5 Conclusion
This investigation establishes an important correlation between patient size , as indicated by Deff and Dw , and the patient ’ s age , with R 2 values ranging from 0.64 to 0.86 , indicating a good relationship . Importantly , our results underline the prevalence of larger Dw values compared to Deff , due to its consideration of tissue composition and X-ray attenuation in patients . Specifically , in male patients , Deff values range from 9.02 to 18.77 cm , while Dw values span from 9.83 to 20.16 cm . Similarly , female patients exhibit Deff values ranging from 8.77 to 17.41 cm , with Dw values falling in the range of 8.92 to 18.37 cm . Noteworthy is the observation that our study ’ s size measurements are consistently lower than those presented in the ICRU 74 report . This discrepancy