Quantification of Scatter Radiation Doses to the Eyes, Thyroid, and Breasts During Plain Abdominal Computed...

The use of computed tomography (CT) has increased tremendously, and at the same time, it has also raised concerns about potential risks such as cataracts and cancers among patients and occupational workers. The majority of studies reported the entrance surface dose to the eyes, thyroid, and breast within the CT scan field of view, without shielding. In the present study, we aim to measure the scatter doses (outside the scan area) to the eyes, thyroid, and breast during a plain abdominal CT scan with (0.5 mm lead equivalence) and without shielding.

A cross-sectional analytical study was designed for participants (n = 93; 51 males (55%), 42 females (45%)) and with shielding (n = 93; 52 males (56%), 41 females (44%)) who underwent plain abdominal CT scans. Scatter radiation doses to the eyes, thyroid, and breast were measured using a CaSO₄:Dy Teflon thermoluminescence dosimeter.

The measured mean ± standard deviation value of without and with shielding are as follows: right eye (0.126 ± 0.170 mSv, 0.030 ± 0.035 mSv), left eye (0.112 ± 0.133 mSv, 0.029 ± 0.035 mSv), right thyroid (0.203 ± 0.296 mSv, 0.102 ± 0.089 mSv), left thyroid (0.210 ± 0.282 mSv, 0.112 ± 0.085 mSv), right breast (0.658 ± 0.863 mSv, 0.287 ± 0.218 mSv), and left breast (0.626 ± 0.842 mSv, 0.273 ± 0.199 mSv). Scatter doses to the eyes were reduced by 74-75% (p < 0.0001), the thyroid by 47-50% (p < 0.0001), and the breast by 56% (p < 0.0001) with shielding compared to scatter doses received by these organs without shielding.

The present study indicates that organs outside the CT scan area received scatter radiation. Shielding significantly reduced the doses to the eyes, thyroid, and breast. Hence, the findings support the use of shielding whenever feasible during a CT scan.