Table 4. Average x-ray absorbance and x-ray scatter signal enhancements measured for organs excised from mice injected IV with 50 nm AuNPs.

	Average signal enhancement due to the presence of gold (%)		Mass of gold taken up by organ (pg)
	X-ray absorbance	X-ray scatter	Au-PEG-COOH	Au-PEG-FB50
Liver	2.8 ± 1.26	23.0 ± 14.13	115 ± 1.1	38 ± 0.5
Kidneys	0.0 ± 7.89	6.4 ± 11.91	3 ± 0.1	3 ± 0.1
Spleen	4.3 ± 8.34	5.1 ± 29.81	30 ± 0.1	13 ± 0.1
Lungs	1.1 ± 9.09	0.9 ± 31.52	1 ± 0.1	0 ± 0.1