IJRECE VOL. 5 ISSUE 4 OCT.-DEC. 2017 ISSN: 2393-9028 (PRINT) | ISSN: 2348-2281 (ONLINE) INTERNATIONAL JOURNAL OF RESEARCH IN ELECTRONICS AND COMPUTER ENGINEERING A UNIT OF I2OR 113 | Page Anatomical and Functional Imaging Modalities: A Brief Review Ayush Dogra 1 , Bhawna Goyal 1 , Sunil Agrawal 1, B.S.Sohi 2 1 UIET, PANJAB UNIVERSITY CHANDIGARH 2 CHANDIGARH UNIVERSITY, CHANDIGARH Abstract—The precise and accurate diagnose of an ailment is foundation of an effective medical aid. For this the medical fraternity relies heavily upon the various radiographic scans which help in the diagnosis, staging and treatment of a particular disease. These imaging modalities depict the anatomical, functional as well as molecular level information about body organs. In this paper we have presented the basic principle, advancement and applications of some of the major imaging modalities. These multi-sensor images depicting complimentary information are fused together to generate a composite image with higher amount of information. Keywords—radiogarphy, radiation, angiogarphy, magnetic resonance, modalities, imaging I. INTRODUCTION Medical Imaging is an extensively studied subject in literature. The various abnormalities which are reflected by the images of different organs of the body are localized with the help of such imaging modalities. There is an abundance of research work published in journals and magazines since 2000 [1]. This can largely be attributed to the fact that there is an increased usage of medical diagnostic devices by the medical community, sustained by advancement in low computing and imaging techniques [2]. The medical technologies like image registration [3,4], image denoising [5,6], image enhancement [7,8,9] and image fusion [10-14] serves an extremely user- friendly platform to the medical practitioners, strengthening their improved and precise diagnosis. The applicability of imaging is not just limited to being an important research topic, rather has reached advanced hospitals across the globe. The general information about structuring of an atom, basic elementary nuclear physics, the generation of X-rays and the nature of electromagnetic radiation is essential to the comprehension of the physics of medical imaging. Radiation may be characterized as particulate or electromagnetic, with electromagnetic waves including visible light, ultraviolet, visible light, X rays and gamma rays and particulate radiation includes electrons, positrons, protons and neutrons. There is a huge variety of medical imaging modalities which serve as fundamental inputs to several imaging technologies. The major kinds of imaging modalities are CT (Computed Tomography), MRI (Magnetic Resonance Imaging), PET (Positron Emission Tomography), X-Ray, Ultrasound, SPECT (Single Photon Emission Tomography) and DSA (Digital Subtraction Angiography). These imaging modalities finds applications in assessment of various organs of the body like brain, bone, teeth, soft tissues, blood vessels, breast and stomach etc [1, 2, 10, 15]. These medical imaging modalities are often corrupted with various types of noises such as MRI is corrupted with Gaussian and Rican noise and PET and SPECT are corrupted with speckle noise [16]. These multi-sensor imaging modalities possess information which is complimentary. These images serve as the primary inputs to the field of medical image fusion. To enhance the image fusion quality, these images need to be denoised and enhanced prior to image fusion In this paper we are presenting a brief insight into basic definition, history, usage and applications of some of the major types of imaging modalities. II. X-RAY Any electromagnetic wave can be distinguished by its amplitude, frequency, wavelength and its velocity. On the electromagnetic spectrum, the wavelength of X-ray ranges in nm (nanometres 10 -9 ) and frequency in the range of 10 16 -10 19 Hz (Hertz). X-rays have wavelengths shorter than the visible light. In some parts across the world X-ray is also known as Rontgen radiation after the name of its discoverer, German scientist Wilhelm Rontgen. It was identified as an unknown radiation, hence the name X-ray is famous since its discovery in 1985. The underlying property that makes X-Ray very popular in medical imaging is that it can identify bone structures. By exposing the patient to the X-ray radiation, 2- dimensional projection radiographs can be produced. The regions where X-rays are blocked by the object in the body are projected as shadows (white areas) on the radiographic plains and the black regions are those areas where the X-Rays are not stopped by the object [17, 18]. The primary body organs capable of blocking the X-Rays and projecting them, which further can be read for ailments using X-ray radiography include bones and soft tissues. One can predict the basic pathology of the skeletal system using X-rays but it harder to depict the type of the tissue (hard or soft) as there are low on density. For instance, chest X-rays are used to identify ailments like pneumonia and lung cancer. Abdominal X-rays can be used to detect the bowel movements along with trapped and free air in the intestines. Dental radiographs are very useful in finding cavities in the teeth. Besides these and several other applications X-rays are also used in management and treatment of skin cancers, lung cancer, breast and prostate cancer. However the X-ray radiography should be handled very carefully as it can cause adverse effects, if a patient is exposed to the higher doses of the same. Fig.1 shows examples of plain radiographs.