Micro CT analysis of Ti2AlC and Al composite

X-ray microtomography, like

tomography Tomography is imaging by sections or sectioning that uses any kind of penetrating wave. The method is used in radiology, archaeology, biology, atmospheric science, geophysics, oceanography, plasma physics, materials science, cosmochemistry, ...

and

X-ray computed tomography X-rays (or rarely, ''X-radiation'') are a form of high-energy electromagnetic radiation. In many languages, it is referred to as Röntgen radiation, after the German scientist Wilhelm Conrad Röntgen, who discovered it in 1895 and named it ' ...

, uses

X-ray X-rays (or rarely, ''X-radiation'') are a form of high-energy electromagnetic radiation. In many languages, it is referred to as Röntgen radiation, after the German scientist Wilhelm Conrad Röntgen, who discovered it in 1895 and named it ' ...

s to create cross-sections of a physical object that can be used to recreate a virtual model ( 3D model) without destroying the original object. The

prefix A prefix is an affix which is placed before the stem of a word. Adding it to the beginning of one word changes it into another word. For example, when the prefix ''un-'' is added to the word ''happy'', it creates the word ''unhappy''. Particu ...

micro- ''Micro'' (Greek letter μ ( U+03BC) or the legacy symbol µ (U+00B5)) is a unit prefix in the metric system denoting a factor of 10−6 (one millionth). Confirmed in 1960, the prefix comes from the Greek ('), meaning "small". The symbol for t ...

'' (symbol: µ) is used to indicate that the

pixel In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest point in an all points addressable display device. In most digital display devices, pixels are the s ...

sizes of the cross-sections are in the

micrometre The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer ( American spelling), also commonly known as a micron, is a unit of length in the International System of ...

range. These pixel sizes have also resulted in the terms high-resolution X-ray tomography, micro–computed tomography (micro-CT or µCT), and similar terms. Sometimes the terms high-resolution CT (HRCT) and micro-CT are differentiated, but in other cases the term high-resolution micro-CT is used. Virtually all tomography today is computed tomography. Micro-CT has applications both in medical imaging and in industrial computed tomography. In general, there are two types of scanner setups. In one setup, the X-ray source and detector are typically stationary during the scan while the sample/animal rotates. The second setup, much more like a clinical CT scanner, is gantry based where the animal/specimen is stationary in space while the X-ray tube and detector rotate around. These scanners are typically used for small animals (''

in vivo Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, and ...

'' scanners), biomedical samples, foods, microfossils, and other studies for which minute detail is desired. The first X-ray microtomography system was conceived and built by Jim Elliott in the early 1980s. The first published X-ray microtomographic images were reconstructed slices of a small tropical snail, with pixel size about 50 micrometers.

Working principle

Imaging system

Fan beam reconstruction

The fan-beam system is based on a one-dimensional (1D) X-ray detector and an electronic X-ray source, creating 2D cross-sections of the object. Typically used in human

computed tomography A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...

systems.

Cone beam reconstruction

The cone-beam system is based on a 2D X-ray detector (

camera A camera is an optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), with a ...

) and an electronic X-ray source, creating projection images that later will be used to reconstruct the image cross-sections.

Open/Closed systems

Open X-ray system

In an open system, X-rays may escape or leak out, thus the operator must stay behind a shield, have special protective clothing, or operate the scanner from a distance or a different room. Typical examples of these scanners are the human versions, or designed for big objects.

Closed X-ray system

In a closed system, X-ray shielding is put around the scanner so the operator can put the scanner on a desk or special table. Although the scanner is shielded, care must be taken and the operator usually carries a dosimeter, since X-rays have a tendency to be absorbed by metal and then re-emitted like an antenna. Although a typical scanner will produce a relatively harmless volume of X-rays, repeated scannings in a short timeframe could pose a danger. Digital detectors with small pixel pitches and micro-focus x-ray tubes are usually employed to yield in high resolution images. Closed systems tend to become very heavy because lead is used to shield the X-rays. Therefore, the smaller scanners only have a small space for samples.

3D image reconstruction

The principle

Because microtomography scanners offer isotropic, or near isotropic, resolution, display of images does not need to be restricted to the conventional axial images. Instead, it is possible for a software program to build a volume by 'stacking' the individual slices one on top of the other. The program may then display the volume in an alternative manner.

Image reconstruction software

For X-ray microtomography, powerful open source software is available, such as the ASTRA toolbox. The ASTRA Toolbox is a MATLAB and python toolbox of high-performance GPU primitives for 2D and 3D tomography, from 2009–2014 developed b
iMinds-Vision Lab
University of Antwerp and since 2014 jointly developed by iMinds-VisionLab, UAntwerpen and CWI, Amsterdam. The toolbox supports parallel, fan, and cone beam, with highly flexible source/detector positioning. A large number of reconstruction algorithms are available, including FBP, ART, SIRT, SART, CGLS. For 3D visualization, tomviz is a popular open-source tool for tomography.

Volume rendering

Volume rendering is a technique used to display a 2D projection of a 3D discretely sampled data set, as produced by a microtomography scanner. Usually these are acquired in a regular pattern (e.g., one slice every millimeter) and usually have a regular number of image pixels in a regular pattern. This is an example of a regular volumetric grid, with each volume element, or voxel represented by a single value that is obtained by sampling the immediate area surrounding the voxel.

Image segmentation

Where different structures have similar threshold density, it can become impossible to separate them simply by adjusting volume rendering parameters. The solution is called segmentation, a manual or automatic procedure that can remove the unwanted structures from the image.

Typical use

Archaeology Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of Artifact (archaeology), artifacts, architecture, biofact (archaeology), biofacts ...

* Reconstructing fire-damaged artifacts, such as the

En-Gedi Scroll The En-Gedi Scroll is an ancient Hebrew parchment found in 1970 at Ein Gedi, Israel. Radiocarbon testing dates the scroll to the third or fourth century CE (210–390 CE), although paleographical considerations suggest that the scrolls may date b ...

and

Herculaneum papyri The Herculaneum papyri are more than 1,800 papyri found in the Herculaneum Villa of the Papyri, in the 18th century, carbonized by the eruption of Mount Vesuvius in AD 79. The papyri, containing a number of Greek philosophical texts, come f ...

* Unpacking cuneiform tablets wrapped in clay envelopes and clay tokens

Biomedical

* Both

in vitro ''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology and ...

and

small animal imaging *Neurons * Human skin samples * Bone samples, including teeth, ranging in size from rodents to human biopsies * Lung imaging using respiratory gating * Cardiovascular imaging using cardiac gating * Imaging of the human eye, ocular microstructures and tumors * Tumor imaging (may require contrast agents) * Soft tissue imaging * Insects – Insect development * Parasitology – migration of parasites, parasite morphology * Tablet consistency checks

Developmental biology Developmental biology is the study of the process by which animals and plants grow and develop. Developmental biology also encompasses the biology of regeneration, asexual reproduction, metamorphosis, and the growth and differentiation of ste ...

* Tracing the development of the extinct Tasmanian tiger during growth in the pouch * Model and non-model organisms (elephants, zebrafish, and whales)

Electronics The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification ...

* Small electronic components. E.g. DRAM IC in plastic case.

Microdevices

* Spray nozzle

Composite materials A composite material (also called a composition material or shortened to composite, which is the common name) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or ...
and metallic foams

* Ceramics and Ceramic–Metal composites. Microstructural analysis and failure investigation * Composite material with

glass fiber Glass fiber ( or glass fibre) is a material consisting of numerous extremely fine fibers of glass. Glassmakers throughout history have experimented with glass fibers, but mass manufacture of glass fiber was only made possible with the inventi ...

s 10 to 12

s in diameter

Polymers A polymer (; Greek ''poly-'', "many" + '' -mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic an ...
,
plastics Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...

* Plastic foam

Diamond Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, ...
s

* Detecting defects in a

diamond Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, ...

and finding the best way to cut it.

Food Food is any substance consumed by an organism for nutritional support. Food is usually of plant, animal, or fungal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is ...
and
seeds A seed is an Plant embryogenesis, embryonic plant enclosed in a testa (botany), protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, includ ...

* 3-D imaging of foods using X-ray microtomography *Analysing heat and drought stress on food crops

Wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of ligni ...
and
paper Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, Textile, rags, poaceae, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre e ...

* Piece of wood to visualize year periodicity and

cell structure Cell structure may refer to: * Cell (biology)#Anatomy * An organelle, or the layout of organelles of the biological cell itself * The structure of a covert cell, often involved in underground resistance, organised crime, terrorism or any group requ ...

Building materials Building material is material used for construction. Many naturally occurring substances, such as clay, rocks, sand, wood, and even twigs and leaves, have been used to construct buildings. Apart from naturally occurring materials, many man-m ...

Concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most ...

after loading

Geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ea ...

In geology it is used to analyze micro pores in the reservoir rocks, it can used i
microfacies
analysis for sequence stratigraphy. In

petroleum Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crude ...

exploration it is used to model the petroleum flow under micro pores and nano particles. It can give a resolution up to 1 nm. *

Sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

Porosity Porosity or void fraction is a measure of the void (i.e. "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. Strictly speaking, some tests measure ...

and flow studies

Fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

Vertebrates Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, wi ...

Invertebrates Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

Microfossils

Micro-CT model of radiolarian, Triplococcus acanthicus

* Benthonic foraminifers

Palaeography Palaeography ( UK) or paleography ( US; ultimately from grc-gre, , ''palaiós'', "old", and , ''gráphein'', "to write") is the study of historic writing systems and the deciphering and dating of historical manuscripts, including the analysi ...

* Digitally unfolding letters of correspondence which employed

letterlocking Letterlocking is the act of folding and securing a written message (such as a letter) on papyrus, parchment, or paper, without requiring it to be contained in an envelope or packet. It is a traditional method of document security that utilizes f ...

Space Space is the boundless three-dimensional extent in which objects and events have relative position and direction. In classical physics, physical space is often conceived in three linear dimensions, although modern physicists usually con ...

* Locating

stardust Stardust may refer to: * A type of cosmic dust, composed of particles in space Entertainment Songs * “Stardust” (1927 song), by Hoagy Carmichael * “Stardust” (David Essex song), 1974 * “Stardust” (Lena Meyer-Landrut song), 2012 * ...

-like particles in

aerogel Aerogels are a class of synthetic porous ultralight material derived from a gel, in which the liquid component for the gel has been replaced with a gas, without significant collapse of the gel structure. The result is a solid with extremely lo ...

using X-ray techniques * Samples returned from asteroid 25143 Itokawa by the

Hayabusa was a robotic spacecraft developed by the Japan Aerospace Exploration Agency (JAXA) to return a sample of material from a small near-Earth asteroid named 25143 Itokawa to Earth for further analysis. ''Hayabusa'', formerly known as MUSES-C ...

mission

Stereo images

* Visualizing with blue and green or blue filters to see depth

Others

Cigarettes A cigarette is a narrow cylinder containing a combustible material, typically tobacco, that is rolled into thin paper for smoking. The cigarette is ignited at one end, causing it to smolder; the resulting smoke is orally inhaled via the oppo ...

*Social insect nests

References

External links

MicroComputed Tomography: Methodology and ApplicationsSynchrotron and non synchrotron X-ray microtomography threedimensional representation of bone ingrowth in calcium phosphate biomaterialsLocating Stardust-like particles in aerogel using x-ray techniquesUse of micro CT to study kidney stonesUse of micro CT in ophthalmologyApplication of the Gatan X-ray Ultramicroscope (XuM) to the Investigation of Material and Biological Samples

3D Synchrotron X-ray microtomography of paint samples
{{Medical imaging Medical imaging Materials science Microtomography Microtechnology X-ray computed tomography Articles containing video clips