Table 1.

Biological scales of imaging

Scale (unit)	Imaging technology	Use
Molecular (angstrom)	Single-particle cryo-electron microscopy (EM) and electron tomography averaging	Structural analysis, molecular function
Molecular machines (nanometer)	Cryo-EM, super-resolution light microscopy (SRM)	Biochemistry, molecular mechanisms
Cells (micrometer)	Transmission EM, volume EM, light microscopy (wide-field, confocal, SRM), electron tomography, 3D scanning EM, soft X-ray tomography	Cellular morphology, activity within cells, mechanism
Tissues (millimeter)	Volume EM, scanning EM, light microscopy (multiphoton, light sheet, OPT, etc.), X-rays (micro-CT), fluorescence imaging, mass spectrometry imaging	Protein localization, tissue morphology and anatomy, interactions between cells
Organism/organ (centimeter)	Photography, X-rays, magnetic resonance imaging, optical tomography technologies, computerized tomography, luminescence imaging	Mechanistic understanding of development and disease

Imaging is used to understand a range of phenomena at different size and time scales. In general, image capture at different scales uses different technologies and records different types of metadata.