X-ray Adsorption Used in Medicine - Assignment Example

X-ray absorption application in medicine Name Date Introduction X-ray is ionizing radiation which exhibit particle-like and wave-like properties. It has very small wavelength that can penetrate far through matter, which makes it both dangerous and useful. Its ionizing radiation can damage the living tissue, thus there is need for safety precaution when dealing with it. X-ray is one of the radiations that form electromagnetic spectrum. They have wavelengths that range between 10-8 m to 10-12 m with frequencies that range between 3×1016 Hz to 3×1019 Hz; Energies range between 100 eV to 100 keV (Denny & Heaton, 1999). The diagram below compares the wavelength and the frequencies of X-rays and other radiations on electromagnetic spectrum. Figure 1: Electromagnetic spectrum (Denny & Heaton, 1999) The common source of these radiations is deceleration of high energy electrons hitting a metal target. They have ability to penetrate objects and that is why they are normally used to image the inner part of objects for example in medicine and security purposes. They are also used to determine crystal structures because their wavelengths are the same as the size of atoms. X-rays have certain properties. One is that it is ionizing radiation, X-ray photons have energy that can ionize atoms and this makes it harmful to tissues (Denny & Heaton, 1999). This ionizing ability is used in treatment of cancer by killing the malignant cells through radiation therapy. Other includes its ability to penetrate objects. X-rays interact with matter in 3 ways that is photoelectric absorption, Compton scattering, and Rayleigh scattering. The interaction strength depends on X-rays energy and what the material is made up of and not the chemical properties of the material. Photoelectric absorption occurs at soft X-ray while and at high energy Compton scattering dominates (Denny & Heaton, 1999). A photon that is photo absorbed transfers energy to the electron that is interacting with, hence ionizing the atom that was carrying the electron. The electron in the outer part will fill the resulting vacant electron space hence producing a characteristic photon. In medical imaging, the interaction between X-rays and soft tissues is referred to as Compton scattering. This is an inelastic scattering of X-ray photon by outer shell electron, and in the process, some photon energy is transferred into the electrons that are scattered hence the atom is ionized and the wavelength of the X-ray will increase. X-rays are normally generated by X-ray tube. X-ray tube is a vacuum tube which utilizes high electrical voltage to increase the speed of electrons produced by hot cathode. X-rays is produced when the fast moving electrons hits a metal target called the anode (Mould, 1993). Figure 2: X-rays are produced by a radiograph In the field of medicine, X-rays are used to identify bones structures and medical imaging. In medical radiography, a patient is placed in from of X-ray detector and illuminated with X-ray pulse radiations. The bones contain calcium and due to its high atomic number, it absorbs X-rays and the amount that will reach the detector will reduces making the inner part of the body clear on radiograph (Mould, 1993). The bones become clear, also lungs and trapped gases can be seen because of its lower absorption as compared to body tissues. Radiographs are important in detecting pathology of the skeletal system and in detecting certain diseases in soft tissues. Some of the examples include chest X-ray which is used to identify diseases which may have affected the lungs like lung cancer and pneumonia, and abdominal X-ray which is used to detect intestines obstructions and free flow of fluids (Mould, 1993). Figure 3: Chest x-ray X-rays help in detecting pathological defects such as presence of kidney stones and other defects not visible to human eye. Original X-rays were less efficient and could not be used to view soft tissue parts of the body (Mould, 1993). With advancement in technology it is now possible to treat optical diseases through the help of dental radiography. Low powerful e-rays have been sidelined in diagnosis of soft tissues because they don’t increase visibility of the images. They have also been rejected widely because of the fear of unnecessary radiation dosage that yields no results. The working mechanism of the x-ray have been stepped up by use of thin metal made of aluminum the cover the opening of the x-ray tube and its purpose is to absorb low power rays and only allows the high power radiation (Mould, 1993). The result of this modification is a hardened beam that allows only the powerful rays that illuminates the image. The get a clear image of veins and arteries a series of procedure is conducted. First the image of the area under investigation is taken and thereafter the blood is injected with contrast agent and another image is taken (Mould, 1993). Once these two images have been obtained, the radiologist then compares the two through subtraction that leaves only iodinated contrast that shows the blood vessels. The resultant vein is compared with the image of the normal one to check whether there is any defect or deformation. X-rays have also made it possible to carry out CT scanning, this is the process whereby an image of the region or tissue being investigated, this process help in obtaining the slice of the tissues or region by comparing two images taken by an x-ray from two different directions (Bokhoven & Lamberti, 2015). The cross-section images obtained through scanning can be used to come up with images of different dimensions that will help in diagnosing a problem. Medical practitioners also use fluoroscope through a process called fluoroscopy to obtain the moving images of the region being viewed, it makes it possible to view the integral parts and structures of the body (Bokhoven & Lamberti, 2015). In the procedure a patient is put in between a fluorescent screen and then illuminated. The modern advanced x-rays have made it possible to record these live images of movements and compositions of body tissues thanks to x-ray imaging intensifier and CCD video camera. Through this it is possible to view the integral part of the heart and identify any defects. Radiotherapy today helps a lot in the treatment of cancer. Radiotherapy however uses high radiation power than one used to just view images (Bokhoven & Lamberti, 2015). High x-ray beam are used to treat modern days critical illnesses like cancer while lower x-ray beams is used to treat skin diseases. Large dosages of radiation sometimes become a problem and it can cause cancer. X-rays have been classified by leading world health bodies and institution like WHO as carcinogen (Bokhoven & Lamberti, 2015). It has been identified that up to 0.4 % of cancer are caused by CT scans and it is projected that this figure will keep growing going into the future. All studies so far curried out do not recommend the percentage below which radioactive procedure will not increase the risk of cancer infection. However this whole proposition has been largely disputed as lacking extensive research and study. The research has also revealed that increased use of radiation among the elderly increase chances of cancer infection. Risk however varies according to the body part being scanned and the type of x-ray being used. References Denny, P. P & B. Heaton (1999). Physics for Diagnostic Radiology. USA: CRC Press. p. 12 Bokhoven, J. A. V., & Lamberti, C. (2015). X-ray absorption and X-ray emission spectroscopy: theory and applications. Chichester, West Sussex, John Wiley & Sons, Inc. Mould, R. F. (1993). A century of x-rays and radioactivity in medicine: with emphasis on photographic records of the early years. Bristol, Institute of Physics Pub. OPPELT, A. (2011). Imaging systems for medical diagnostics fundamentals, technical solutions and applications for systems applying ionization radiation, nuclear magnetic resonance and ultrasound. Erlangen, Publicis Corporate Pub Read More