New and emerging tomographic imaging techniques in medical and industrial applications. Introduction.

A considerable degree of progress has been achieved in new and emerging tomographic imaging systems in the past few decades. These techniques include optical tomography (Gibson et al. 2005), electromagnetic tomography (Griffiths 2001), electrical impedance tomography (Bayford 2006), ultrasound tomography (Glide-Hurst et al. 2008), magnetoacoustic tomography (Xu & He 2005) and magnetic resonance electrical impedance tomography (Woo & Seo 2008), to name a few. On close examination, it is apparent that there are clear areas of overlap in the development of these imaging technologies. Methodologies developed in one technology can be transferred to others. From a mathematical prospective image, reconstruction can be considered in a common class of inverse problems (Kaipio et al. 2000; Soleimani 2008). Researchers in the two specific application areas of tomography do not always export the developments across disciplines. Similarly, theoretical mathematicians need to develop techniques in close collaboration with the system designers and the end users. The objectives of this issue are to bring together in one publication a range of different application areas with the common aim of improving the quality of the reconstructed image. We have invited some of the well-known scientists and leading figures in their respective fields to present their findings. The combination of these papers covers a wide range of scientific approaches to imaging for different application areas. In this special issue, various new methods and techniques have been presented. Gibson & Dehghani (2009) present an overview of recent developments in medical applications of diffuse optical tomography (DOT). The main advancements in DOT are in brain mapping and breast imaging. This is linked to the image reconstruction paper by Dehghani et al. (2009), which played a very important role in the development of optical tomography. In Dehghani et al. (2009), different aspects of the image reconstruction of optical tomography are presented. The paper presents some imaging results, demonstrating the current capabilities of single wavelength, spectral and spatial imaging in near infrared, using experimental and patient data. Microwave tomography (MWT), an important member of the new and emerging electromagnetic tomography, has been included. Semenov (2009) presents an expert overview on difficulties of using MWT for applications and presents results for MWT for various applications including breast cancer detection, diagnostics of lung cancer, brain imaging and cardiac imaging.