Table 3.

Imaging Modalities

Modality	Signal/contrast	Translational	Preclinical	Sensitivity*	Resolution	Depth	Quantitative	Target	Acquisition time (s)	Cost†
PET	11C, 13N, 15O, 18F, 64Cu, 68Ga, 89Zr, 124I	Yes	Yes	1	1–2 mm	No limit	Yes (very good)	Molecular	10–100	$$$
SPECT	99mTc 123/125I 201Tl 111 In, 177Lu, 67Ga, 133Xe	Yes	Yes	10−1-10−2	<1 mm	No limit	Yes (good)	Molecular	100–1,000	$$
MRI	Hydrogen, gadolinium, magnetic or paramagnetic particles	Yes	Yes	10−5	10–100 μm	No limit	Yes (fair)	Anatomic, molecular	100–1,000	$$$
MR spectroscopy Hyperpolarization (13C, 15N, 129Xe, 3He)		Yes	Yes	<10−5	5 mm	No limit	Yes (fair)	Molecular	100–1,000	$$$
Ultrasound	Echoes, microbubbles	Potential	Yes	10−3	50 μm	Centimeter Yes (poor)		Anatomic, molecular	<1	$$
Bioluminescence	Luciferase (reporter gene)	No	Yes	1–102*	<10 mm	Centimeter Yes (poor to fair)†		Molecular	1–10	$$
Fluorescence	Fluorescent proteins, fluorochromes, quantum dots	Potential	Yes	10−2-1*	2–3 mm	<1 cm	Yes (poor to fair)†	Molecular	1–10	$

^*Relative to that of PET.

^†For high-resolution, small-animal imaging systems (clinical imaging systems differ). Cost is based on purchase price of imaging systems in United States.

^$=low

^$$=intermediate cost

^$$$=high cost.

^‡Depth-dependent