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Industrial process tomography possesses unique advantages in biphasic medium measurement and has received broad attention in the past decades. Aiming at the widely existing low-contrast biphasic medium, this article proposes a nonlinear ultrasonic transmissive tomography (UTT) approach using continuous-wave excitation. Considering the refraction effect at the biphasic interface, the reconstruction method with nonlinear forward problem and the prototype-based resolution enhancement algorithm is proposed with higher accuracy, resolution, and speed. The UTT system is improved with a high-voltage excitation module and fan-beam transducer array to evaluate the proposed method, where the performance is qualitatively and quantitatively compared with the state-of-the-art reconstruction algorithms and measurement techniques from different perspectives. The results show that the reconstruction performance is significantly improved where the size, shape, and position of the dispersed medium can be accurately discriminated. Accordingly, the ultrasonic tomography with continuous-wave excitation is proved to be feasible and efficient in the visualized measurement of low-contrast biphasic medium.

The measurement of volume fractions of different components in multiphase flows is of great interest in many industrial applications. Ultrasound process tomography is especially well-suited for the differentiation of gaseous and liquid phases. This paper presents a measurement system, which was developed for real-time ultrasound process tomography, utilizing a ring of 32 ultrasound transducers on a measurement pipe. Simulations and measurements were conducted, and a reflection-mode reconstruction technique was used to obtain the system's point spread function and examine the performance on inhomogeneous configurations of water containing multiple gaseous objects. Furthermore, the possibility of increasing the measurement rate by reducing the number of excitations and its effects on the quality of the reconstructed images is investigated.

This study describes the development of a multisource computed tomography (CT) system that proved to be a useful tool to study multiphase systems. In this CT system, two different radioisotope sources, 192 Ir (317 keV and 448 keV) and 137 Cs (662 keV), were placed in a single lead collimator and several tomography measurements carried out. The multisource CT system was capable of determining as well as differentiating the attenuation coefficients of materials with two phases (gas and liquid). It was also able to provide important information concerning the hydrodynamics occurring inside a multiphase column.

Ultrasonic tomography is a powerful tool for identifying defects within an object or structure. But practical application of ultrasonic tomography to solids is often limited by time consuming transducer coupling. Air-coupled ultrasonic measurements may eliminate the coupling problem and allow for more rapid data collection and tomographic image construction. This research aims to integrate recent developments in air-coupled ultrasonic measurements with current tomography reconstruction routines to improve testing capability. The goal is to identify low velocity inclusions (air-filled voids and notches) within solids using constructed velocity images. Finite element analysis is used to simulate the experiment in order to determine efficient data collection schemes. Comparable air-coupled ultrasonic signals are then collected through homogeneous and isotropic solid (PVC polymer) samples. Volumetric (void) and planar (notch) inclusions within the samples are identified in the constructed velocity tomograms for a variety of transducer configurations. Although there is some distortion of the inclusions, the experimentally obtained tomograms accurately indicate their size and location. Reconstruction error values, defined as misidentification of the inclusion size and position, were in the range of 1.5-1.7%. Part 2 of this paper set will describe the application of this imaging technique to concrete that contains inclusions.

The concept of creating a composite tissue-type-image (cTTI) along with an associated probability image is introduced for ultrasound and microwave tomography. The cTTI integrates information available within different quantitative property images, and the associated probability image provides an indication of the level of confidence regarding the reconstructed tissue types. It is shown that the cTTI concept can be applied to ultrasound tomography property images, microwave tomography property images, as well as to their combination. Thus, the concept is generalizable to the amalgamation of quantitative information derived from a wide variety of modalities with the goal of increasing the confidence in the reconstructed cTTI. Validation of the concept is performed on MRI-derived numerical breast phantoms containing up to five different tissue types.

Three-phase flow imaging is a very challenging problem in industrial process tomography. A particular interest here is three phase flow including both conductive and non-conductive phases. Currently there is no robust solution to this problem. Electrical capacitance tomography (ECT) has been applied to visualize the permittivity distribution by measuring inter-capacitance between electrodes around sensing area. Magnetic inductance tomography (MIT) is a technique to image the conductivity distribution through the inductance measurements over the coils around the sensing area. In this paper, the three-phase flow is classified into two scenarios: air background and water background. A dual-modality method of ECT and MIT is proposed to image both the conductive and dielectric components under test. As a result of this experiment, the dual-modality method is able to solve air-background three-phase flow imaging, but a problem has been raised in the water-background scenario. The static experiment results are promising for such contactless three phase flow imaging.

Electrical capacitance tomography (ECT) is a well-established industrial process tomography technique. The application of ECT is generally limited to imaging insulating objects with permittivity contrast. Although ECT imaging for grounded conductors are studied earlier, there is not a systematic study of imaging floating metals using ECT. To broaden the application of the ECT, imaging of suspended metallic samples is studied in this paper. Placing a metallic conductor between electrodes has an effect of shortening the spacing between the electrodes, thus the capacitances are increased. This increment in capacitances can be regarded as placing a dielectric sample with higher permittivity than the reference data. An ECT image of the floating metallic samples can be reconstructed using traditional sensitivity based image reconstruction, which is in the same way as imaging dielectric permittivity. In this paper, both metallic and dielectric samples are tested, and the results show the feasibility of ECT imaging for floating metals.

The main advantages of the use of computed x-ray tomography for nondestructive testing of the state of the internal structure of laminated polymer composite materials with the aim of improving the quality of manufacture of products from composites have been demonstrated.

Presently, non-invasive techniques are in vogue and preferred standard clinical approach because of its limitless advantages in monitoring real time phenomenon occurring within our human body without much interference. Many techniques such as ultrasound, magnetocardiography, CT scan, MRI etc., are used for real time monitoring but are generally not recommended for continuous monitoring. The limitations created by above used techniques are overcome by a proposed technique called non-invasive bio-impedance technique such as Electrical Impedance Technique (EIT). EIT imaging technique is based on internal electrical conductivity distribution of the body. The reconstruction of cross sectional image of resistivity required sufficient data collection by finite element method using MATLAB software. The EIT technique offers some benefits over other imaging modalities. It is economical, non-invasive, user friendly and emits no radiation thus appears to be one of the best fit technology for mass health care to be used by the basic health worker at a community level.

X-ray luminescence and X-ray fluorescence computed tomography (CT) are two emerging technologies in X-ray imaging that provide functional and molecular imaging capability. Both emission-type tomographic imaging modalities use external X-rays to stimulate secondary emissions, either light or secondary X-rays, which are then acquired for tomographic reconstruction. These modalities surpass the limits of sensitivity in current X-ray imaging and have the potential of enabling X-ray imaging to extract molecular imaging information. These new modalities also promise to break through the spatial resolution limits of other in vivo molecular imaging modalities. This paper reviews the development of X-ray luminescence and X-ray fluorescence CT and their relative merits. The discussion includes current problems and future research directions and the role of these modalities in future molecular imaging applications.

Measurement and visualization of the fracture process zone (FPZ) in the silicate composites is essential for understanding how the crack is formed and how it is propagating through the material. Although several time-lapse radiography and tomography experiments during the three-point bending of silicate composites with conventional imaging techniques have been already realized, the crack initiation and propagation is so fast process, that it is very difficult to capture sufficient spatial information in the exact moment when this process is occurring. Nowadays progress in X-ray imaging instrumentation, especially single photon counting CdTe detectors with a fast parallel readout, allows speeding up the acquisition of the tomographic data while keeping the intrinsic resolution of tens of micrometers and high efficiency even for photons with higher energy. Tomography of relatively fast processes is becoming realistic even in laboratory conditions using commercially available microfocus X-ray tubes. As an example of such a fast tomography, results of “on-the-fly” series of tomographic experiments performed on the specimen subjected to continual three-point bending test is presented.

Usage of electrical impedance tomography and electrical resistance tomography will be in the article. The electrical impedance tomography is a widely investigated problem with many applications in physical and biological sciences. Medical imaging can be used primarily for the detection of pulmonary emboli, non-invasive monitoring of heart function and blood flow, and for breast cancer detection. Electrical resistive tomography is use in the geophysical imaging is used for searching underground conducting fluid plumes near the surface and obtaining information about rock porosity or fracture formation. Another application of electrical impedance tomography is for example in non-destructive testing and identification of material defects like cracks or identification of corrosion in production materials. The principle of electrical impedance tomography and Electrical resistive tomography is based on the back image reconstruction, which is highly ill-posed inverse problem. The aim of both methods is to reconstruct, as accurately and fast as possible, the internal impedance or conductivity distributions in two or three dimensional models.

Infrared thermal imaging based on active thermal excitations has been widely used for nondestructive evaluation (NDE) of materials. While the experimental systems have remained essentially the same during the last few decades, development of advanced data-processing methods has significantly improved the capabilities of this technology. However, many limitations still exist. One fundamental limitation is the requirement, either explicitly or implicitly, of the tested material to be homogeneous such that detected thermal contrasts may be used to determine an average material property or attributed to flaws. In this paper, a new thermal tomography (TT) method is introduced, which for the first time can evaluate heterogeneous materials by directly imaging their thermal-property variations with space. It utilizes one-sided flash thermal-imaging data to construct the three-dimensional (3D) distribution of thermal effusivity in the entire volume of a test sample. Theoretical analyses for single and multilayer material systems were conducted to validate its formulation and to demonstrate its performance. Experimental results for a ceramic composite plate and a thermal barrier coating (TBC) sample are also presented. It was shown that thermal diffusion is the primary factor that degrades the spatial resolution with depth for TT; the spatial resolutions in the lateral and axial directions were quantitatively evaluated.

Multiphase flow imaging is a very challenging and critical topic in industrial process tomography. In this article, simulation and experimental results of reconstructing the permittivity profile of multiphase material from data collected in electrical capacitance tomography (ECT) are presented. A multiphase narrowband level set algorithm is developed to reconstruct the interfaces between three- or four-phase permittivity values. The level set algorithm is capable of imaging multiphase permittivity by using one set of ECT measurement data, so-called absolute value ECT reconstruction, and this is tested with high-contrast and low-contrast multiphase data. Simulation and experimental results showed the superiority of this algorithm over classical pixel-based image reconstruction methods. The multiphase level set algorithm and absolute ECT reconstruction are presented for the first time, to the best of our knowledge, in this paper and critically evaluated. This article is part of the themed issue ‘Supersensing through industrial process tomography’.

Electrical capacitance tomography (ECT) is a non-destructive detection technique for imaging the permittivity distributions inside an observed domain from the capacitances measurements on its boundary. Owing to its advantages of non-contact, non-radiation, high speed and low cost, ECT is promising in the measurements of many industrial or biological processes. However, in the practical industrial or biological systems, a deposit is normally seen in the inner wall of its pipe or vessel. As the actual region of interest (ROI) of ECT is surrounded by the deposit layer, the capacitance measurements become weakly sensitive to the permittivity perturbation occurring at the ROI. When there is a major permittivity difference between the deposit and the ROI, this kind of shielding effect is significant, and the permittivity reconstruction becomes challenging. To deal with the issue, an interface and permittivity simultaneous reconstruction approach is proposed. Both the permittivity at the ROI and the geometry of the deposit layer are recovered using the block coordinate descent method. The boundary and finite-elements coupling method is employed to improve the computational efficiency. The performance of the proposed method is evaluated with the simulation tests. This article is part of the themed issue ‘Supersensing through industrial process tomography’.

Non-intrusive visualization of the structure of flames can offer us many advantages in studying the reaction mechanisms of combustion and observing special distributions of the parameters required for the development of equipment such as jet engines and gas turbines. Process tomography is a relatively new technique for such a task, but is useful owing to its fast speed and capability of detecting signals related to ionizations caused by chemical reactions and thermal effects. Electric capacitance tomography (ECT) is one of the process tomographic techniques. ECT usually comprises a sensor array of electrodes that detect permittivity variations in the measuring zone, a data-logging device and a computer that controls data acquisition and carries out image reconstruction. There have been studies on ECT imaging of flames; however, ECT has not been exploited sufficiently to reveal the inner structure of the flames. In this study, a sensor with planar electrodes is created, and the associated three-dimensional sensitivity map is generated by the finite-element method to detect flame structure. A series of experiments are carried out covering a range of feed rates of fuel and air. Data are collected by the ECT sensor and hardware. The results of the ECT reconstruction show good agreement with actual features, and the structure of the flame is found. This opens up a new route for the study of flames. This article is part of the themed issue ‘Supersensing through industrial process tomography’.

Magnetic Induction Tomography (MIT) is a new and emerging type of tomography technique that is able to map the distribution of all three passive electromagnetic properties, however most of the current interests are focusing on the conductivity and permeability imaging. In an MIT system, coils are used as separate transmitters or sensors, which can generate the background magnetic fleld and detect the perturbed magnetic fleld respectively. Through switching technique the same coil can work as transceiver which can generate fleld at a time and detect the fleld at another time. Because magnetic fleld can easily penetrate through the non-conductive barrier, the sensors do not need direct contact with the imaging object. These non-invasive and contactless features make it an attractive technique for many applications compared to the traditional contact electrode based electrical impedance tomography. Recently, MIT has become a promising monitoring technique in industrial process tomography, for example MIT has been used to determine the distribution of liquidised metal and gas (high conductivity two phase ∞ow monitoring) for metal casting applications. In this paper, a low conductivity two phase ∞ow MIT imaging is proposed so the reconstruction of the low contrast samples (< 6S/m) can be realised, e.g., gas/ionised liquid. An MIT system is developed to test the feasibility. The system utilises 16 coils (8 transmitters and 8 receivers) and an operating frequency of 13MHz. Three difierent experiments were conducted to evaluate all possible situations of two phase ∞ow imaging: 1) conducting objects inside a non-conducting background, 2) conducting objects inside a conducting background (low contrast) and 3) non-conducting objects inside a conducting background. Images are reconstructed using the linearised inverse method with regularisation. An experiment was designed to image the non-conductive samples inside a conducting

We describe the achievements of the Karpenko Physicomechanical Institute of the Ukrainian National Academy of Sciences in the development of new methods and tools for the ultrasonic computer tomography of structural materials in the last decade. The results of investigations of thick-plate products with welded joints performed by using a transmission ultrasonic computer tomograph are presented. We also describe the technologies of evaluation of the space distribution of scattering power of the metal in thick-walled pipelines by recording scattered ultrasonic signals with the help of an ultrasonic computer tomograph. These technologies prove to be promising for implementation at the objects of nuclear power plants. The results of experimental testing of the technologies of passive ultrasonic computer tomography are discussed.

This paper presents a novel method of combining dual modality electrical capacitance and optical tomography for applications in monitoring and investigating solid/gas flow. The objective of this method is to obtain a good quality image of the full-scale concentration distribution of solid/gas flow. A new image reconstruction algorithm fused the dual modality images is developed and evaluated.

Summary 3D electrical-impedance tomography (EIT) is a technique that has the potential to provide estimates of reservoir saturation at multiple scales by determining the resistivity distribution within the subsurface. In theory, EIT is well suited for researching oil and brine systems because of the large contrast in resistivity between the two phases. Here, in our initial laboratory investigation, we have applied the EIT technique to measure the saturation distribution of water within a core. The initial EIT experiment presented here used a Berea-sand-stone core with 48 electrodes attached in three rings of 16. The core was open to the atmosphere, with saturation occurring by natural imbibition and desaturation occurring by evaporation. The voltage-potential field was measured by applying a direct-current (DC) pulse across the core and measuring the voltage potential at all electrodes, essentially applying the four-wire resistance technique over all electrodes in turn. The result was a data set that embodies the resistivity distribution within the core, and, by inversion, the resistivity distribution was reconstructed, which allowed for the inference of the saturation. The data processing was accomplished by using the Electrical Impedance Tomography and Diffuse Optical Tomography Reconstruction Software (EIDORS) toolkit, which was developed for application to this nonlinear and ill-posed inverse problem. The procedure uses a finite-element model for forward calculation and a regularized nonlinear inverse solver to obtain a unique and stable inverse solution. Experiments have indicated that EIT is a viable technique for studying the displacement characteristics of fluids with contrasting resistivity and is capable of detecting displacement fronts in near to real time. The current system is also a quantitative technique able to measure saturation distributions accurately between 15% < Sw < 65% in a Berea sandstone core. These limitations were imposed because of connate-water connections to the electrodes and ion-mobility effects caused by the DC voltage source. It is anticipated that the applicability of EIT will increase with the implementation of an alternating-current (AC) voltage source.

Multi-phase flow imaging is a challenging topic in industrial process tomography. In this paper, we present a non-invasive imaging technique for the electrically conductive phase of a multi-phase flow problem. Magnetic induction tomography (MIT) is sensitive to the conductivity of the target, and as such has the potential to be used as an imaging technique to visualise the conductive components in a multi-phase flow application. A 16 channel MIT system is used for this study, among which eight excitation coils are supplied with a 15 V peak, 13 MHz sinusoidal signal in sequence from a signal generator, while the remaining eight coils are floated as receivers. The imaging region of this MIT system has an inner and outer diameter of 190 mm and 200 mm respectively. Static fluid distribution patterns are produced using several fluids with different conductivities and placed inside the imaging region to form conductivity phase contrasts. Experimental results show within our hardware and software capability, a conductivity contrast of 0.06 S/m for an inclusion that occupies 8.69% of the imaging region can be imaged. An in-depth experimental evaluation of the system response towards various fluid measurements is shown for the first time, as are results for quasi-static fluid experiments showing that a non-homogenous flow of gas bubbles can be imaged in various conductive backgrounds. In sum, the analyses presented investigate the feasibility and capability of MIT for this application, while also reporting some of the first flow rig tests in this field.

Optical Tomography (OT) is a form of computed tomography using a digital model of the volume of an object by reconstructing an image of the light transmitted and scattered by the object. OT is used mostly as a form of research in medical imaging. OT depends on the reference object being at least partially light transmitting or translucent, so it works best on soft tissue, such as breast and brain tissue. Optical Coherence Tomography (OCT) is a new technology for performing high-resolution cross-sectional imaging. OCT is similar to ultrasound imaging, but uses different types of light instead of sound. OCT can provide cross-sectional images of tissue structure on the micrometer scale and in real time. OCT serves as a kind of optical biopsy and is used as a medical diagnostic imaging technology because, unlike conventional histopathology, it does not require the removal and processing of tissue specimens for microscopic examination. The study was carried out to see how the two types of optical imaging and the use of concepts and components used in the system. The light source is used to show different levels of penetration and resolution for both methods is used. The use of an interferometer in optical imaging applications is discussed along with examples of commonly used methods. The optical imaging method contributes significantly to the diversity of tomography systems.

We present a new setup for time-resolved diffuse optical tomography based on multiple source-detector acquisitions analysed by means of the Mellin-Laplace transform. The proposed setup has been used to perform pre-clinical measurements on rats in order to show its suitability for non-invasive assessment of flap viability.

The objective of this study is to develop and test a unique X-ray-induced acoustic computed tomography system that combines the advantages of high X-ray imaging contrast and high ultrasonic spatial resolution. The system features a 5 MHz 128-element ultrasound transducer ring-array formed into a full circular aperture. A parallel data receiver, which consists of a dedicated 128-channel preamplifier and a 128-channel data acquisition module, provides full tomographic imaging at a speed of up to 25 frames per second. Details of the system design and calibration are presented, along with the characteristic results of the imaging resolution. The tomographic imaging performance is demonstrated through images of a phantom with a spatial resolution up to 138 μm. The study results indicate that this imaging device and the methodology provide a rapid and high resolution approach for the dynamic imaging of information, and it may have the potential for becoming a promising noninvasive imaging modality to be used in...

Terahertz (THz) tomography is a recent imaging technique allowing 3D inspection of opaque objects. In this paper, we investigate a dual-energy experimental setup and a THz tomographic reconstruction algorithm based on dual-energy measurements. We discuss how this dualenergy approach is able to extract physical properties of acquired samples in addition to the 3D reconstruction from acquisitions measured with a 84/287GHz transmission scanner.

The measurement of volume fractions and their spatial distribution in multiphase flows is of great interest in many industrial applications. Ultrasound methods are well-suited for the differentiation between liquid and gaseous phases. In a system for ultrasound process tomography, the signal transmission characteristics strongly vary with the composition and the spatial distribution of the phases in the multiphase flow. In this contribution, a simulation technique for ultrasound process tomography of gas / liquid flows is presented, which uses ray-tracing for the simulation of ultrasound wave propagation. The received signals obtained after transmission through the liquid phase and scattering at the interfaces between the liquid and the gaseous inhomogenities are efficiently calculated in the frequency domain. The simulation concept and some results of simulated exemplary scenarios are discussed.

Tomography is a method that has been used for image reconstruction in the medical and engineering fields. Optical tomography is one of the various methods applied in tomography systems. This tomography method is widely used in the medical and processing industries fields because of its special characteristics, such as immunity to electrical noise and interference, high resolution and its hard field sensors. The basic principle of the optical tomography system in measuring an object is based on its wave and radiation source. This article is a review of the characteristics of light and its interaction with matter, the types of optical tomography system, the basic construction of an optical tomography system, types of optoelectronic sensors and image reconstruction.

In contrast to X-rays, neutrons can penetrate most metals easily. Neutron attenuation is strongly isotope dependent, and a high contrast is possible for many light-weight elements. Especially their high sensitivity for hydrogen makes them a valuable tool for the detection of organic materials like lubricants, plastics or sealants within metal housings. Neutron radiography and tomography complement the application of X-rays for the inspection of complex and critical components like in automotive and aerospace applications. However, the requirements for beam geometry are much higher for tomography than for simple radiography because the sample cannot be close to the detector, as the sample has to be rotated in the beam, usually by 180°. This paper gives an overview on tomography requirements and limitations, applications and future prospects.

Electron tomography is a powerful technique for 3D characterization at the nanoscale. Recent developments focus on extracting a wide range of information about a sample in 3D [1]. Of special interest is the combination of electron tomography with spectroscopic techniques EFTEM, EELS and EDS to recover the information present in spectroscopic signals in three dimensions. Analytical electron tomography allows mapping of chemical variations and gradients, approaching the goal of full 3D elemental quantification [2]. Additionally, EELS tomography can be used to extract information about materials properties or chemical bonding [3,4]. In this presentation we will discuss the steps necessary to successfully combine spectroscopy and tomography and show respective applications.

X-ray computed tomography is a 3D imaging technique for the non-invasive, non-destructive visualisation and measurement of the internal microstructure of materials. Using X-rays, a series of radiographs of a sample are recorded from different angles, and then used to reconstruct the internal 3D microstructure by means of a suitable reconstruction algorithm. The method has a high penetrating power and probing efficiency, and is unlimited by morphological complexity. This chapter describes the technique, its advantages and limitations, the latest technological advances, and reviews of applications in food systems.

In integrated positron emission tomography (PET)/magnetic resonance imaging (MRI), the PET data acquisition is performed simultaneously to the magnetic resonance data acquisition, leaving latitude for the duration of PET acquisition time. This establishes emission time as an important parameter in forthcoming PET/MRI protocols because it is one of the key factors determining PET image quality. Thus, the purpose of the current study was to identify optimal duration of PET acquisition time in PET/MRI.A total of 22 consecutive patients (7 men, 15 women) underwent fluorine-18-labeled fluorodeoxyglucose (18[F]FDG) PET/MRI after clinical PET/computed tomography. Positron emission tomography/magnetic resonance scans were acquired for 8 minutes per bed position (mpb). Positron emission tomography was extracted to reconstruct images with 2, 4, 6, and 8 mpb for each patient. Visual and quantitative approaches were used to assess image quality and lesion detectability for each image. For image quality, (a) 3 readers independently scored subjective image quality on a 4-point scale and (b) a region-of-interest approach was used to obtain a quantitative estimate of image quality in terms of noise. For lesion detectability, (a) the readers independently counted the number of hypermetabolic lesions and (b) signal-to-noise ratio and contrast-to-noise ratio were computed in a region-of-interest approach. Moreover, the mean and maximal standardized uptake value (SUV mean and SUV max, respectively) of the hypermetabolic lesions was compared across all acquisition times.For image quality, subjective image quality significantly declined from 8 to 2 mpb (P; 0.05), with the exception of the difference between 6 and 8 mpb. Image noise increased with shorter imaging duration, ranging from 13% on average in the 8-mpb scans to 23% in the 2-mpb scans (differences were statistically significant for 2 vs 6 mpb, 2 vs 8 mpb, and 4 vs 8 mpb; P; 0.05). For lesion detectability, 39 hypermetabolic lesions were identified by consensus. There was no difference in detected lesions across all acquisition times. Signal-to-noise ratio and contrast-to-noise ratio were constantly high and did not differ significantly across the acquisition times. The SUV mean and SUV max did not differ significantly across all acquisition times.Positron emission tomography acquisition times on integrated PET/MRI do not need to exceed usual acquisition times on current PET/computed tomography scanners: Although the PET image quality suffers from short acquisition times, even a duration of 2 mpb permits sufficient lesion detection. Moreover, quantitative measures of tracer uptake are also reasonably precise at short acquisition times.

This chapter begins by reviewing several research projects which were considered to be useful for industrial application in the IRMMW – THz 2010 conference. Next, our recent studies of industrial applications are introduced: a computed tomography system using terahertz (THz) to millimeter waves, and a time-of-flight (TOF) THz tomography system. In the study of the tomography system, non-destructive investigation of the soot-removal filter installed in the internal combustion engine is demonstrated. Finally, a component analysis method for powder material using THz waves is introduced.

UMIST is one of the establishments where process tomography techniques were first developed. This paper introduces the development of capacitance tomographic imaging systems at UMIST for oil pipeline measurements. The principles of electrical capacitance tomography (ECT) are briefly presented and two ECT systems based on charge/discharge capacitance measuring circuits are described. These systems, a PC‐based 8‐electrode system and a Transputer‐based 12‐electrode system, have been used to visualise oil pipelines. Future developments of ECT technology are discussed, including a low‐cost PC‐based ECT system, a twin‐plane ECT system which can measure the velocity profile of a pipeline flow, a multi‐frequency ECT system using ac capacitance measuring circuits and an ECT system with a rotating parallel excitation field.

This work describes a multi-source computed tomography. It showed to be a feasible tool to study multiphase systems. In this CT scanner, two different radioactive sources, 192Ir and 137Cs, were placed together into a single lead collimated system. The CT is capable to determine and differentiate the attenuation coefficients of materials constituted of three phases (gas, liquid and solid), using two or more different radioisotope energies.

Magneto-acoustic-electrical tomography (MAET) is a new Electrical Impedance tomography technology, which combines traditional Electrical impedance tomography and Ultrasound Imaging, can provide high-spatial-resolution information. This paper firstly introduce the fundamental principle and theoretical basis based on Magneto-acoustic-electrical effect, then the simple experiment system is set up and the experimental process of Magneto-acoustic tomography is expounded. The experimental results show that MAET detection technique has the potential to allow the electrical conductivity of imaging volume to be determined using ultrasound.

In this paper a review of the development of x-ray computed tomography (CT) for non-destructive failure analysis in microelectronics packages and boards is presented. The general operation principle, key design considerations and technical challenges faced by x-ray CT technology are discussed. A comparison between 2D and 3D x-ray imaging capabilities is presented, and critical failure analysis case studies for first and second level interconnect that are hard or not possible to isolate by alternative methods are also discussed, as well as its unique progressive testing capability.

We first clarify the measurement process of fluorescent x-ray computed tomography using synchrotron sheet-beam. Then, we propose the analytical reconstruction method, and show its efficacy by computer simulation.

The article deals with characteristics of tomography associated with the interaction of X radiation with a material, mathematical scan processing, and random errors in determination of linear attenuation coefficients.

We report applications of full-field swept-source optical coherence tomography (SS-OCT) for non-destructive testing and evaluation. Results of topography and tomography of latent fingerprints, silicon microelectronic circuits and composite materials are presented. The system is completely non-mechanical scanning, compact and low-cost.

A rapid time domain terahertz computed axial tomography (CT‐TD‐THz) system is described. The system is used to reconstruct three dimensional structure of aerospace components including: Kevlar soft shell fan containment systems, silica thermal protection tiles, and sprayed on foam thermal insulation.