Table 2.

Advantages and limitations of hypoxia imaging modalities.

Techniques	Labels	Signal measured	Advantages	Limitations	Cost	Throughput	Resolution	References
PET	Radiotracers	Positrons from radionuclides	High sensitivity and specificity	Radioactive Limited spatial resolution Low SNR	High	Low	5‒7 mm	33-48
BOLD-MRI	Label-free	Magnetic field alterations	Noninvasive Label-free High spatial resolution	Low sensitivity and specificity Susceptible to physiological factors Time-consuming scans	High	Low	1‒2 mm	50-54
OE-MRI	Label-free	Magnetic field alterations	Noninvasive Label-free High spatial resolution	Low sensitivity Limited specificity Time-consuming scans	High	Low	1‒2 mm	54-59
DCE-MRI	Gadolinium-based contrast agents	Vascular perfusion/permeability	High spatial resolution	Low sensitivity and specificity Time-consuming scans Require multiparametric analysis	High	Low	1‒2 mm	60-62
FMI	Fluorescent probes	Light	No radiation Low cost Live monitoring High sensitivity	Invasiveness, Limited tissue penetration	Low	High	2‒3 mm	16-19,24,25,27-32,63,64,71,106
PLI	Oxygen-sensitive luminescent probes	Light	No radiation, Direct oxygen levels quantification	Invasiveness Probe safety Complex imaging system Limited tissue penetration	Low	High	3‒5 mm	13-15,72-74
PAI	Label-free or Probes	Sound	Noninvasive High spatial-temporal resolutions Deep tissue penetration	Probe safety	Low	High	1 mm	26,67,75-82
CLI	Label-free or Oxyphros probes	Cherenkov photons	Live monitoring High sensitivity	Radioactive Limited tissue penetration	Low	High	3‒5 mm	83-87

PET: positron emission tomography; BOLD-MRI: blood oxygen level-dependent magnetic resonance imaging; OE-MRI: oxygen-enhanced magnetic resonance imaging; DCE-MRI: dynamic contrast enhancement magnetic resonance imaging; FMI: fluorescent molecular imaging; PLI: phosphorescence lifetime imaging; PAI: photoacoustic imaging; CLI: Cherenkov luminescence imaging.