Tomography

The word tomography is derived from greek words ‘tomo’ meaning section or part and ‘graphein’ meaning write. Sectioning of images generated by wave incursion is referred as tomography. An appliance which produces sectioning images is called as tomography and the sectioned image is referred as tomogram. Mathematical approach of tomography is termed as tomographic reconstruction. It finds its own application in the field of material science, biology, archeology, radiology, astrophysics and geophysics.

Types of tomography

Based on the source of data, tomography is classified as mentioned below.

• Confocal laser scanning microscopy (LSCM) or optical sectioning helps in surface profiling
• Cryo electron tomography to construct 3D sample image
• Atom probe tomography (APT) involves position sensitive detector
• Electrical impedance tomography (EIT) helps in medical imaging
• Electrical resistivity tomography (ERT) helps in geophysical imaging
• Electrical capacitance tomography (ECT) determines dielectric permittivity
• Magnetic induction tomography (MIT) utilize electromagnetic properties
• Neutron tomography produce 3D image with the help of neutron source
• Magnetic resonance imaging (MRI) helps in medical imaging
• Functional magnetic resonance imaging (fMRI) measures blood flow
• Optical coherence tomography (OCT) for micrometer resolution
• Ocean acoustic tomography (OAT) measures temperatures
• Optical projection tomography (OPT) utilize optical microscope.
• Photoacoustic imaging in medicine (PAT) developed on photoacoustic effect
• Positron emission tomography (PET) helps in nuclear medicine
• Positron emission tomography computed tomography (PET-CT) helps in medical imaging
• Quantum tomography reconstructs quantum state
• Seismic tomography determines properties of earth
• Single photon emission computed tomography (SPET) helps in nuclear medicine
• Thermoacoustic imaging (TAT) helps in absorption properties of body parts
• Ultrasound modulated optical tomography (UOT) involves ultrasound
• X-ray computed tomography helps in medical imaging
• Zeeman Doppler imaging helps in reconstruction of image

Tomography techniques

• Discrete tomography: Helps in binary image reconstruction. It is used in medical image processing.
• Process tomography: It measures object periphery and used in the field of medicine.