TABLE 1

Calculated TLD-to-CTDI_vol Ratios for Head Region

	90 kVp			120 kVp			140 kVp
mAs	TDL	CTDI_vol	Ratio	TDL	CTDI_vol	Ratio	TDL	CTDI_vol	Ratio
Brain
25	1.39	1.80	0.77	3.21	3.80	0.85	5.08	5.50	0.92
50	2.76	3.50	0.79	7.29	7.60	0.96	10.18	10.90	0.93
100	4.98	7.10	0.70	12.61	15.20	0.83	20.51	21.90	0.94
150	7.82	10.60	0.74	19.60	22.80	0.86	27.37	32.80	0.83
200	11.20	14.10	0.79	25.05	30.40	0.82	38.84	43.70	0.89
250	13.93	17.10	0.81	32.48	38.10	0.85	49.98	54.70	0.91
300	17.00	21.20	0.80	37.79	47.70	0.79	65.07	65.60	0.99
Eyes
25	1.94	1.80	1.08	3.71	3.80	0.98	5.44	5.50	0.99
50	3.44	3.50	0.98	8.82	7.60	1.16	13.66	10.90	1.25
100	6.56	7.10	0.92	15.22	15.20	1.00	23.73	21.90	1.08
150	9.27	10.60	0.87	21.11	22.80	0.93	30.14	32.80	0.92
200	14.92	14.10	1.06	28.81	30.40	0.95	46.79	43.70	1.07
250	18.93	17.10	1.11	34.61	38.10	0.91	56.30	54.70	1.03
300	20.31	21.20	0.96	49.72	47.70	1.04	69.76	65.60	1.06

Data are milligrays.