Table 1.

Overview of imaging systems

Imaging modalitya	Resolution	Depth	Temporal resolution	Sensitivityb	Quantitative	Costc	Clinical use
MRI	10-100 µM	No limit	Minutes to hours	10−3 to 10−5 M	Yes	Most expensive	Yes
CT	50 µM	No limit	Minutes	no probes	No	Expensive	Yes
PET	1–2 mm	No limit	Minutes to hours	10−11 to 10−12 M	Yes	Most expensive	Yes
SPECT	1–2 mm	No limit	Minutes to hours	10−10 to 10−12 M	Yes	Most expensive	Yes
Bioluminescence	3–5 mm	cm	Minutes	10−15 to 10−17 M	No	Cheap	No
Fluorescence	2–3 mm	cm	Minutes to hour	10−9 to 10−12 M	No	Cheap	No

^aTable adapted from Blasberg, 2003 and Vassaux and Groot-Wassink, 2003.

^bProbe concentrations.

^cCost is based on purchase price of the imaging system.