Electromagnetic Radiation In Relation To Radiology
Electromagnetic radiation is a concept which occurs as self-propagating waves in any form of matter. The major components of electromagnetic radiation are magnetic and electric fields which move in an oscillatory manner perpendicularly to each other. The two fields also move perpendicularly to the direction in which the energy moving the waves originates. There are quite a variety of electromagnetic waves which vary due to the nature of frequencies of the waves as well as the wavelength. Examples include: X-rays, radio waves, gamma rays and ultraviolet waves. A certain fraction of the wavelengths are visible using the naked eye such as the visible light while most of them are invisible to normal human eyes. Normal light is considered as an example of an electromagnetic radiation due to the close resemblance of its speed and that of the electromagnetic wavelengths. Electromagnetic radiation is measured using photon which is the basic unit of measuring light and it is also the carrier for electromagnetic force.Radiology on the other hand is a branch in medicine which uses the knowledge behind electromagnetic properties to carry out imaging tasks such as CT scans, MRI.s and X-rays inpatient to enable accurate diagnosis. Radiology utilizes imaging technologies like x-rays, computated tomography (CT scans), and magnetic resonance imaging (MRIs) to diagnose and treat disease.
Properties of electromagnetic radiation which makes it useful in radiology
Electromagnetic radiation is composed of magnetic and electric fields which are capable of superimposing. This means that at any given time, the various fields present at that point are bound to contribute to the existing fields hence increasing the radiation as they are vectors. Therefore, an electromagnetic wave in motion found in an object causes the atoms of that item to oscillate hence they emit their own electromagnetic wavelengths and this leads to refraction or diffraction of light (Tipler, 2004).Refraction enables the wave moving from one medium to the other to change its speed and direction hence making it easier to capture images below the surface. This property makes it possible for radiologists to trace the particles or light inside various organs when administering drugs in patients (Yu and Watson, 1999).The other equally significant property of electromagnetic radiation is the length of the waves. Shorter wavelengths have been crucial in determining the rate at which the radiation can penetrate through solids. X-rays are high energy electromagnetic radiations with the ability to penetrate through human flesh as well as quite a variety of physical objects apart from lead (Tipler, 2004).Another property of electromagnetic radiations is the ability of the wavelengths and particles to emit heat especially when they move to higher energy levels. When the photon absorbs enough energy, it excites an electron in the atom and over time, the electron moves to a higher energy level hence emitting more energy in the process. Therefore, the amount of light emitted is dependent on the energy level moved by the electrons as well as the level of excitement. After the energy has been released, it is absorbed by the object and it is portrayed as light which is reflected outwardly. This application used to determine the distance of an object in addition to its position in the human body (Yu, 1999).
Applications of electromagnetic radiation to radiology
During diagnostic procedures in hospitals, an X-ray tube is aimed at the patient where it generates a series of rays which are filtered as they pas through the individual’s skin. The filtration reduces chances of scattering as well as unnecessary noise in preparation to striking the undeveloped film. This was the old way of applying electromagnetic radiation in radiography as over the years, a digital reconstructed radiograph has been developed which allows the radiologist to minimally expose the patient to X-rays by using a simulated environment to carry out virtual X-rays (Tipler, 2004).The ability of X-rays as well as gamma rays to penetrate through human flesh presents a favorable opportunity to use them when examining inner tissues and organs. Similarly, the ability of the electromagnetic radiation to absorb energy as well as changing the direction of motion when they encounter a different medium makes them crucial in radiology. Cancerous cells which are often lodged in critical organs such as the brain are distinguished by use of Projectional radiology (Filler, 2010).
This application of electromagnetic radiation involves use of high energy X-ray photons to identify and portray real-time images of various activities in body structures which are in motion. Usually a fluorescent screen is fitted to an image intensifier which directs the images obtained to a closed circuit television such that the radiologist is able to track the movements of the object (Kwan-Hoong, 2003).Fluoroscopy incorporates radiocontrast agents such as barium sulfate which are either swallowed or injected into the patient and their movement traced throughout the various body systems. The property of the compound that allows it to be used in determination of the normal functioning of body systems is its ability to absorb electromagnetic radiation and then reflect the energy as light. The radiocontrast material scatters x-rays as it moves through various channels in the body and the motion is exhibited in the closed-circuit television. Radiologists carry out fluoroscopy to diagnose rectal problems as well as blockage of major blood vessels in the body (Filler, 2010).
CT scans are used together with radiocontrast agents to produce realm images of various organs in the body which are presented in cross-section. The CT scans have undergone tremendous evolution to increase its resolution hence producing clearer images. X-ray detectors are used together with tubes which generate the rays and where the two meet the organ is delineated such that the rays pass through the tissue to yield an almost real image. Kidneys stones and appendicitis are detected through application of computated tomography (Herman, 2009).
Radiologists employ electromagnetic radiation to carry out non-ionizing scans on patient who have pathological problems in delicate tissues. High frequency sound waves are used to penetrate through tissues only as ultrasound does not allow penetration through bones or vacuum (Kwan-Hoong, 2003).Most of the ultrasound applications are conducted on pregnant mothers to determine the progress of the fetus as the radiations are able to process motion images. Electrical pulses are used to transfer the sound waves from the organ at the desired frequency usually 2-18 MHz. These waves are subjected to phased arrays which allow the radiation to change the direction as well as the intensity of the sound wave in relation to the nature of organs where it is penetrating (Filler, 2010).The sound waves are received by the transducer in the form of vibrations which are translated into electric impulses that are presented by the scanner in the form of digital images. A computer run frame-grabber is used to portray the image on the screen of a computer showing the various structures (Kwan-Hoong, 2003).
Magnetic resonance imaging (MRI)
MRI is probably the most effective radiology technique which is carried out in soft tissues whereby the imaging machine employs intense magnetic fields to body tissues. Radio frequencies are obtained for signals generated by realignment of nuclei which are initially subjected to a move that makes them lay on the same axis as the magnetic field. The signals are relayed to the imager who produces images with relatively high resolutions. Patients who are undergoing MRI scans are often asked to remain still for longer periods of time to reduce chances of receiving mixed signals (Filler, 2010).
Electromagnetic radiation is the basis of radiology as every detail which is considered before applying specific tools is determined by the property of the radiation. Some techniques portray mixed properties which others are often subjected to a single aspect which puts it way above others. Radiology has borrowed heavily from physics in relation to the physical properties of matter which has led to increased efficiency in the medical field hence more lives are saved through accurate diagnosis.
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Herman, G. T. ( 2009), Fundamentals of computerized tomography: Image reconstruction from projection, 2nd edition, Springer
Kwan-Hoong N. (20 – 22 October 2003), "Non-Ionizing Radiations – Sources, Biological Effects, Emissions and Exposures": Proceedings of the International Conference on Non-Ionizing Radiation at UNITEN ICNIR2003 Electromagnetic Fields and Our Health. Retrieved on June 25, 2010 from: http://www.who.int/peh- emf/meetings/archive/en/keynote3ng.pdf
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