Effect of Different Breast Densities and Average Glandular Dose on Contrast to Noise Ratios in Full-Field Digital Mammography: Simulation and Phantom Study

Table 1

CNR values based on mammary gland density and imaging conditions.

Fibroglandular adipose mass (%)	Thickness of phantom (mm)	Target filter	Tube voltage (kV)	mAs; (mAs)	AGD; (mGy)	CNR
Phantom A; (30/70)	10	Mo/Mo	26	16.7	0.48	23.1
	20		26	27.9	0.75	20.1
	30	Mo/Rh	27	41.7	1.01	16.2
	40		28	57.1	1.27	15.1
	50	Rh/Rh	29	60.8	1.33	13.0
	60		29	74.9	1.58	11.7
	70		30	90.2	1.95	10.9
Phantom B; (50/50)	10	Mo/Mo	26	18	0.53	21.8
	20		26	34	0.85	20.8
	30	Mo/Rh	27	47.2	1.07	16.0
	40	Rh/Rh	29	50.1	1.2	13.7
	50		30	52.4	1.23	11.4
	60		31	59.7	1.49	9.6
	70		30	75	1.47	8.4
Phantom C; (70/30)	10	Mo/Mo	26	19.1	0.54	21.8
	20		26	37.8	0.87	19.1
	30	Mo/Rh	27	44	0.9	13.8
	40	Rh/Rh	29	59.7	1.23	12.6
	50		30	69	1.55	10.6
	60		30	64	1.29	9.0
	70		30	95.3	1.73	8.1

AGD: average glandular dose, CNR: contrast to noise ratio, Mo: molybdenum, and Rh: rhodium.