Average absorbed dose in some organ positions in the phantom during head CT scans with and without bismuth shielding on eyes.

Table 2: Average absorbed dose in some organ positions in the phantom during head CT scans with and without bismuth shielding on eyes.

Organ position	Average absorbed dose (mGy)
Organ position	Without bismuth shielding	With bismuth shielding	Head tilted
Lenses	17.44 ± 0.66^a	9.49 ± 0.57	2.46 ± 0.57
Thyroid	2.35 ± 0.30	1.05 ± 0.41	1.33 ± 0.45
Pharynx	2.46 ± 0.28	1.20 ± 0.32	0.85 ± 0.29
Parotid Gland	22.97 ± 0.69	20.18 ± 0.81	3.90 ± 0.64
Salivary Gland	4.29 ± 0.55	2.65 ± 0.38	1.25 ± 0.32
Hypophysis	15.35 ± 0.47	13.79 ± 0.46	10.06 ± 0.67
Breast	0.94 ± 0.26	0.49 ± 0.22	0.58 ± 0.36
Spinal Cord	1.74 ± 0.56	0.48 ± 0.58	0.85 ± 0.38

^aStandard deviation.