M . Keshtkar : Radioprotection 2024 , 59 ( 2 ), 131 – 137 135
Figure 2 . Cancer incidence risk ( per 100,000 individuals ) of different organs for three age groups .
was observed in group 2 ( 5 –< 10 ). The CTDI vol and DLP measured in this study did not exceed the reference levels reported in literature surveys on paediatric CT chest radiation dose for all age groups ( Gao et al ., 2018 ; Radiology , 2016 ; Shrimpton et al ., 2006 ; Verdun et al ., 2008 ).
The calculation of SSDE in this study also took into account the patient ’ s effective diameter as a crucial factor in estimating the absorbed dose during the CT scan . By considering the effective diameter , which represents the average cross-sectional dimension of the patient , the SSDE calculation provides a more accurate estimation of the absorbed dose specific to the patient undergoing the CT scan . The mean values of SSDE ( mGy ) in the CD-CT protocol group were 2.1 ± 0.5 , 2.5 ± 0.6 , and 2.6 ± 0.5 for G1 , G2 , and G3 , respectively . Also , the corresponding values in the RC-CT protocol group were 4.5 ± 1.2 , 5.5 ± 1.2 , and 5.7 ± 2.1 for G1 , G2 , and G3 , respectively . These findings show that the radiation doses in terms of SSDE were statistically lower in the CD-CT protocol group compared to the RC-CT protocol group for all three age groups . Specifically , the mean SSDE values in the CD-CT group were roughly half of those observed in the RC-CT group for each age group . These results demonstrate that the choice of CT protocol can significantly impact the radiation dose received by pediatric patients during CT imaging , highlighting the importance of carefully selecting the appropriate protocol to minimize radiation exposure .
The SSDE values for the two chest CT protocols used in our study ’ s G1 age group were lower than those reported in previous studies by Karim et al . ( 4.6 mGy ), Admontree et al . ( 5.2 mGy ) and Mohammadbeigi et al . ( 7.4 mGy ). Similarly , the SSDE values for the two chest CT protocols used in our study ’ s G2 age group were lower than those reported in previous studies by Karim et al . ( 6.7 mGy ), Admontree et al . ( 6.1 mGy ), Mohammadbeigi et al . ( 11.1 mGy ), and Strauss et al . ( 5.1 mGy ). Additionally , the SSDE values for the two chest CT protocols used in our study ’ s G3 age group were lower than those reported in previous studies by Karim et al . ( 7.6 mGy ), Admontree et al . ( 6.3 mGy ), Mohammadbeigi et al . ( 10.4 mGy ), and Strauss et al . ( 6.6 mGy ).
The results of the organ dose analysis in chest CT imaging revealed that the lung received the highest radiation dose , followed by the esophagus , breast , thyroid , and stomach . These results are consistent with the study by Karim et al . ( 2021 ), with the exception that they reported a higher radiation dose to the breast than to the thyroid gland , which may be related to difference in setting the upper border of scanning range . Therefore , exact setting of the scanning range during chest CT scanning may be necessary to reduce the radiation dose to the thyroid . It is worth noting that they also used the NCICT software to calculate the organ doses . In line with previous comparison studies ( Karim et al ., 2021 ), our results showed a pattern of increasing organ doses with age , with the lowest values observed in the youngest age group and a gradual increase in doses with increasing age . The results of the organ dose analysis in our study were lower than those reported in other comparable studies ( Giansante et al ., 2019 ; Karim et al ., 2021 ). The organ doses in CD-CT protocol are significantly lower than the RC-CT protocol , indicating that the use of CD-CT protocol may be a more favorable option for reducing radiation exposure in pediatric patients undergoing CT imaging .
The most current researches suggest compelling evidence linking the occurrence of cancer to low-level radiation exposure from CT examinations ( Alkhorayef , 2018 ; Hong et al ., 2019 ). The results of the cancer incidence risk analysis indicated that the lung had the highest risk for males , while the breast had the highest risk for females across all age groups . Even though the lung received the highest radiation dose in females , the breast had a higher cancer risk than the lung across all age groups , which is in line with Tahmasebzadeh et al . ( 2021 ) study . This is because , according to Table 12D-1 in the BEIR VII report , the breast has a higher cancer risk than the lung up to 20 years of age .
Furthermore , the results showed that the incidence risk of thyroid and lung cancer is higher in females than in males . According to Table 12D-1 in the BEIR VII report , females have a higher cancer risk than males for both types of cancer across all age groups .
In contrast to our findings , Karim et al . ( 2021 ) reported the highest cancer risk in the thyroid for females . This may be related to the different used reports for estimating cancer risk , where they utilized ICRP 103 publication report . Based on the ICRP 103 publication report , the nominal risk coefficient value