Key Terminology for

Soft X-Ray Microscopy

and Biological Imaging

A
Absorption Contrast Microscopy

Absorption contrast microscopy is a technique used to visualize specimens based on differences in their ability to absorb light. It works by using the natural absorption properties of the sample, enhancing the contrast between different structures or components in the sample.

Automated Imaging

Automated imaging refers to the use of technology, software, and systems to capture, process, analyse, or interpret images with minimal human intervention.

B
Bench-Top Microscope

A compact microscope designed to be placed in a standard laboratory.

Bioengineering

Also known as biomedical engineering, Bioengineering is a multidisciplinary field that applies principles of engineering, biology, and medicine to develop technologies and solutions that improve healthcare and the understanding of living systems

Biological Imaging

A range of techniques used to visualize biological structures and processes in living organisms, tissues, or cells. These techniques allow scientists and medical professionals to observe the form, function, and dynamics of biological systems.

C
Cell Imaging

A branch of biological imaging focused specifically on visualising the structure, function, and behaviour of cells. It uses various microscopy and imaging techniques to observe live or fixed cells at different levels of detail.

CLEM (Correlative Light and Electron Microscopy)

An advanced imaging technique that combines the strengths of light microscopy and electron microscopy to study biological samples with both functional and structural detail.

CLSM (Confocal Laser Scanning Microscopy)

A powerful imaging technique used to produce high-resolution, optically sectioned images of biological samples, especially cells and tissues. CLSM uses laser light and pinholes to scan a specimen point-by-point and build up a sharp image—eliminating out-of-focus blur that’s common in traditional fluorescence microscopy.

Cryo-Electron Microscopy (Cryo-EM)

A form of transmission electron microscopy where biological samples are rapidly frozen (vitrified) to preserve their natural structure in a glass-like layer of ice that allows scientists to visualize biological molecules in near-atomic detail.

Cryo-Electron Tomography (Cryo-ET)

An advanced imaging technique that combines cryo-electron microscopy (cryo-EM) with 3D tomography to visualize the internal architecture of cells, organelles, and macromolecular complexes in their native, frozen-hydrated state—without staining or chemical fixation.

Cryo-fluorescence Microscopy (Cryo-SRFM)

An advanced imaging technique that combines super-resolution fluorescence microscopy with cryogenic temperatures to visualize biological samples with high molecular specificity and improved structural preservation.

Cryo-Grid Inspection

Vitrified EM grids containing biological cells are inspected using light and low magnification soft X-ray microscopy to identify regions of interest for soft x-ray tomography.

Crystallography

A scientific technique used to determine the atomic and molecular structure of a crystal. By analyzing the way a crystal scatters X-rays, scientists can figure out the exact positions of atoms inside the crystal—essentially creating a 3D blueprint of the molecule.

Cryo Soft X-ray Tomography (Cryo-SXT)

An advanced 3D imaging technique used to visualize whole, intact biological cells in a near-native, frozen-hydrated state—with high resolution and without the need for chemical staining or sectioning.

E
Electron Microscopy (EM)

A powerful imaging technique that uses a beam of electrons instead of light to create highly detailed images of biological and material samples. Because electrons have much shorter wavelengths than visible light, EM can reveal structures at nanometer and even atomic resolution.

F
Fluorescence Microscopy (FM)

A widely used imaging technique that allows scientists to visualize and track specific molecules inside cells and tissues by tagging them with fluorescent dyes or proteins.

Focused Ion Beam (FIB)

A high-resolution imaging and micromachining technique that uses a focused beam of ions (typically gallium ions) to precisely mill, image, and modify the surface of a sample at the nanometer scale. FIB is often used in combination with Scanning Electron Microscopy (SEM) to provide a complete toolkit for both imaging and sample preparation.

Focused Ion Beam Scanning Electron Microscopy (FIB-SEM)

See FIB definition above.

H
Hard X-ray Tomography

A non-destructive imaging technique that uses high-energy X-rays to create 3D images of the internal structure of a sample. Unlike soft X-rays, which are typically used for biological imaging, hard X-rays have much higher energies and can penetrate denser materials like metals, minerals, and composites, allowing for high-resolution imaging of solid objects without the need for sectioning.

High-Resolution Imaging

High-Resolution Imaging refers to the ability to capture fine details of a sample with great precision, resulting in images that show small structures and features that are usually not visible in lower-resolution images.

High-Throughput Imaging

Automated acquisition and analysis of large volumes of images at a fast pace, typically in biological, medical, or materials science research.

Hydrated Samples

Samples that are in a moist or water-containing state during imaging, analysis, or experimental processes. Maintaining the hydration of biological, chemical, or material samples is crucial in many types of research because it helps preserve their native state, ensuring that the sample behaves as it would in its natural environment.

I
Image Contrast

The difference in brightness or color between the light and dark areas of an image. In scientific imaging, especially in microscopy and other imaging techniques, contrast is an essential factor that helps to distinguish between different structures or features within a sample.

Image Reconstruction

The process of generating or restoring an image from raw data or a series of measurements. It is commonly used in imaging systems where the acquired data is not in the form of a complete, direct image but needs to be processed or assembled into a usable visual representation.

Image Segmentation

A process in computer vision and image analysis where an image is divided into multiple meaningful parts or segments. The goal is to simplify and/or change the representation of an image into something more understandable and easier to analyze.

Imaging Workflow

The sequence of steps and processes involved in sample preparation, capturing, processing, analyzing, and interpreting an image in various types of imaging systems.

Intermediate Focus Point

A focusing point or location along an optical beamline where the beam of light (usually X-rays, but also potentially other forms of radiation such as UV or infrared) is focused after passing through certain optical components. Typically used as a location for beam diagnostics, improving beam quality, intensity or spatial resolution.

L
Label-Free Imaging

A set of imaging techniques that allow the visualisation and analysis of biological, chemical, or material samples without the need for exogenous labels, dyes, or contrast agents, relying instead on the intrinsic properties of the sample itself to provide contrast.

Laser-Produced Plasma (LPP)

A process in which a high-intensity laser beam is focused onto a target material, typically a solid, liquid, or gas, causing the material to ionize and form a plasma. The generated plasma emits light, which can be harnessed for a variety of applications, such as in the generation of extreme ultraviolet light, X-rays, or even as a tool in research and diagnostics.

Light Microscopy (LM)

A technique used to observe and magnify objects that are too small to be seen with the naked eye, utilising visible light and optical lenses. It is one of the most fundamental tools in biological research, material science, and various other fields.

R
Region of Interest (ROI)

Refers to a specific part or section of a sample, image, or data set that is selected for further analysis or study.

S
Sample Preparation

A critical first step in any imaging or microscopy workflow. It involves the processes and techniques used to make a biological, chemical, or material sample ready for observation, analysis, or imaging under a microscope or other analytical instruments.

Single Particle Electron Microscopy (SP-EM)

A technique that uses electron microscopy to study individual macromolecules or complexes—such as proteins, nucleic acids, or large molecular assemblies—at high resolution. It is a form of cryo-electron microscopy (cryo-EM) that enables the imaging of individual particles in a frozen, hydrated state, without the need for crystallization or other sample preparations that might alter the molecule’s structure.

Soft X-Ray Imaging

See SXM and SXT below

Soft X-Ray Microscopy (SXM)

A powerful imaging technique that uses soft X-rays (wavelengths between ~2–4.4 nm, or energies ~280–540 eV) to visualize intact, hydrated biological and material samples at high resolution—typically down to 30–50 nm.

Soft X-Ray Tomography (SXT)

A powerful 3D imaging technique that uses soft X-rays (wavelengths between ~2–4.4 nm, or energies ~280–540 eV) to visualize intact, hydrated biological samples at high resolution—typically down to 30–50 nm. It is especially useful for imaging whole cells in near-native states, without sectioning or staining, offering detailed structural insights into organelles and subcellular architecture.

Spatial Resolution

A measure of how clearly you can see the fine details in an image.

Subtomogram Averaging (STA)

A powerful technique used in cryo-electron tomography to improve the resolution of 3D structures by averaging multiple copies of the same object (called subtomograms) extracted from tomograms.

Synchrotron

A type of particle accelerator that produces extremely bright, high-energy electromagnetic radiation, especially X-rays, by accelerating charged particles—typically electrons—to near the speed of light and forcing them to travel in circular paths using strong magnetic fields.

T
Transmission X-Ray Microscopy (TXM)

A high-resolution imaging technique that uses X-rays to visualize and analyze the internal structure of materials and biological samples. In TXM, X-rays pass through a sample, and the resulting transmitted X-ray beam is captured by a detector (such as a CCD camera or scintillator).

Tilt Series Acquisition

A technique used in electron tomography and X-ray tomography to collect a series of 2D projection images of a sample at different angles. These images are then used to reconstruct a 3D volume of the sample’s internal structure.

Tomographic Reconstruction

The process of creating a 3D image or volume of an object from a series of 2D projection images obtained from various angles.

W
Water-Window Imaging

A unique imaging technique that takes advantage of the specific absorption properties of water and biological tissues in a particular range of X-ray wavelengths, typically around 2.3 to 4.4 nanometers. This region, known as the water window, is where water absorbs X-rays very weakly, while carbon-based materials (such as organic tissues and biomolecules) absorb X-rays much more strongly. This creates a significant contrast between water-containing and carbon-rich materials in biological samples, making it especially useful for imaging biological structures without the need for staining or contrast agents.

Whole-Cell Imaging

The technique of capturing detailed images of entire cells, including their structure, organelles, and interactions within the cellular environment.

Workflow Integration

The process of streamlining and connecting different steps, tools, and technologies involved in an overall task or project, particularly in the context of scientific research, data analysis, and image processing. In microscopy and imaging studies, workflow integration ensures that all stages—from sample preparation to image acquisition and analysis—work smoothly together, allowing for efficient and reproducible results.