Table 5:
Absorbed radiation dose to the lenses of the eye and parotid and thyroid glands for each imaging techniquea
| Absorbed Dose Right Lens (mGy) | Absorbed Dose Left Lens (mGy) | Absorbed Dose Right Parotid Gland (mGy) | Absorbed Dose Thyroid Gland (mGy) | |
|---|---|---|---|---|
| CT | 9.25 ± 1.69 | 9.69 ± 1.08 | 8.87 ± 1.68 | 0.45 ± 0.13 |
| Conebeam CT | 0.28 ± 0.01b | 0.4 ± 0.03b | 0.69 ± 0.05 | 0.05 ± 0.05 |
| Difference | 8.97c | 9.29c | 8.18c | 0.4c |
a
Data are mean values ± SD.
b
For Conebeam CT, the absorbed radiation dose to the left lens was significantly higher than the dose to the right lens because the x-ray tube describes a 190° rotation around the left side of the patient's face.
c
P < .001.