. Author manuscript; available in PMC: 2022 Aug 1.

Published in final edited form as: Curr Opin Chem Biol. 2021 Mar 15;63:78–85. doi: 10.1016/j.cbpa.2021.01.014

Table 1.

Features, advantages and disadvantages, and examples of imaging agents of techniques commonly used in the context of nanomedicine development [8,53,54].

Technique		Imaging agent	Spatial resolution	Sensitivity	Penetration in tissue	Advantages	Disadvantages
Anatomical	CT	Au, Iodine	<0.2 mm [P] 0.5–1 mm [C]	mM	No limit	Fast; high spatial resolution	Ionizing radiation; low contrast sensitivity
Anatomical	MRI	Iron oxide, Gd, Mn	<0.1 mm [P] 1–2 mm [C]	μM-mM	No limit	High spatial resolution; soft tissue contrast	Low contrast sensitivity; time-consuming
Nuclear	PET	¹⁸F, ⁶⁴Cu, ⁶⁸Ga, ⁸⁹Zr	1–2 mm [P] 6–10 mm [C]	fM	No limit	High sensitivity; quantitative	Ionizing radiation; expensive; limited spatial resolution
Nuclear	SPECT	^99mTc, ¹¹¹In, ¹²³I, ¹²⁵I	0.5–2 mm [P] 7–15 mm [C]	<pM	No limit	High sensitivity; quantitative	Ionizing radiation; expensive; limited spatial resolution
Optical	FI	Fluorophores, quantum dots	1–5 mm [P]	nM	mm-cm	High sensitivity; multiplexing; inexpensive	Low penetration depth
	FMT	Fluorophores, quantum dots	<1 mm [P]	pM	cm	High sensitivity	Signal attenuation; limited penetration
	IVM	Fluorophores, quantum dots	<1 μm [P] 1 μm [C]	<nM	<mm	Cell-level resolution; real time imaging	Complex setup; limited field of view

[P]: preclinical; [C]: clinical; FI: fluorescence imaging; FMT: fluorescence molecular tomography; IVM: intravital microscopy.