Principles of Positron Emission Tomography (PET) Scanning BE908: Biomedical Instrumentation
Assignment 2
By Alazar Tesfay Tekie
How does PET scan works?
Positron emission tomography (PET) is a nuclear imaging technology (molecular imaging) that works in the principle of radio tracer injected into the human body that enables visualization of metabolic processes in the human body. A radio tracer is a radioactive medicine used in conjunction with a natural chemical such as glucose, water, or ammonia. PET systems have sensitive detector panels to capture gamma ray emissions, creating 3-D computed PET images in the areas where the radioactive tracer concentrations are rich enough with in the body. The unique features of PET Scan are not into the
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Radioisotopes can be produced by separation of the by-product produced using fission; they can be produced from neutron irradiation in a reactor; or they can be produced from the bombardment of a target material by changed particles from accelerator. First, the cyclotron bombards non-radioactive elementinthetargetwithacceleratedparticlesthe followingradioactiveisotopes produced C-11, N-13, O-15, and F-18 are excited by charged particles bombardment. F-18 thus produced is delivered to the chemical synthesis unit where it will be incorporated to produce a final product, the label sugar molecule fluorodeoxyglucose (FDG). The entire process can take place in hospital settings in side cyclotron laboratory.
References:
1.Davies, H. (2016). Positron Emission Tomography Scanning. EBME. Retrieved 13 November 2016, from http://www.ebme.co.uk/articles/clinical-engineering/73- positron-emission-tomography-scanning
2.How does a PET scan work? (2016). Medical News Today. Retrieved 12 November 2016, http://www.medicalnewstoday.com/articles/154877.php#how_does_a_PET_scan_w ork
3.. Positron Emission Tomography: (2016). Retrieved 12 November 2016, from https://www.iop.org/education/teacher/resources/teaching-medical- physics/positron/file_56287.pdf
4. PET Scan: Frequently Asked Questions. (2016). Petscaninfo.com. Retrieved 13 November 2016, from http://www.petscaninfo.com/zportal/portals/pat/faq#faq3 5. PET scan - NHS Choices. (2016). Nhs.uk. Retrieved 13 November 2016, from
When taking a radiograph there are some precautions that can be taken to reduce some of the radiation that can be exposed to a patient, what would be used on all patients is call a lead apron and thyroid collar, these aprons are used to protect the patients that may be a bit more radiosensitive and also may give the patient a little of reassurance that they will be protected. “Radiosensitivity is the relative susceptibility of cells, tissues, organs, organisms, or other substances to the injurious action of radiation.”
One might ask, what is Spectral Computed Tomography (CT)? Spectral CT is a way for us as health professionals to add diagnostic value to our exams by using the full spectrum of an x-ray beam. To summarize, “Spectral CT acquires data sets at both low- and high-kVp settings” (Lentz 2014). Spectral CT was first studied back in the 1980’s, but Stefan Ulzheimer, PhD, said, “Because of various hurdles, it never made it into clinical practice” (Lentz 2014). John W. Steidley, PhD, states in his article Exploring the Spectrum, “While these exercises were of academic interest, CT detector technology at the time wasn’t yet advanced enough to separate the x-ray beam into its component spectrum” (Steidley 2008).
The description of PET scans in detail requires the understanding of the radioactive substance injected into the subject. First, a small amount of a biochemical substance is tagged with a positron-emitting radioisotope. A positron is an “anti-electron.” Positrons are given off during the decay of the nuclei of the radioisotope. When the positron emitted collides with an electron in the tissue of the subject, both the positron and the electron are annihilated. When this happens, the collision produces two gamma rays having the same energy (511 KeV), but going in opposite directions.
A Growing Concern." Internet Journal of Radiology 5.2 (2007): 4. Academic Search Premier. Web. 23 Nov. 2013.
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which are then interpreted by a radiologist to diagnose a patient. To become a radiologic
Two major examples of phenomena used to image in the cancer field are the positron emission tomography (PET) and the single photon emission computed tomography (SPECT). The way that the “PET” works is that it creates computerized images of chemical changes, such as sugar in the metabolism, that take place in tissue. The radioactive sugar can help in the search to locating a tumor in a person’s body. Due to the reason that cancer cells take up or absorb sugar more avidly than other tissues in the body this is how the tomography is able to appear. If a tumor is present, the radioactive sugar will accumulate in the tumor. A computer translates this information into the images that are interpreted by a radiol...
Radiology is one of the few so-called “physical-science”-based fields of medicine, making it a challenging and rewarding application of an academic interest in science. It combines advanced knowledge of human physiology with principles of atomic physics and nuclear decay, electricity and magnetism, and both organic and inorg...
"Radioisotopes in medicine." World of Physics. Gale, 2007. Science in Context. Web. 19 May 2014.
As a starting point in CT diagnostic imaging the form of radiation used to provide an image are x-rays photons , this can also be called an external radiation dose which detect a pathological condition of an organ or tissue and therefore it is more organ specific. However the physics process can be described as the radiation passes through the body it is received by a detector and then integrated by a computer to obtain a cross-sectional image (axial). In this case the ability of a CT scanner is to create only axial two dimensional images using a mathematical algorithm for image reconstruction. In contrast in RNI the main property for producing a diagnostic image involves the administration of small amounts of radiotracers or usually called radiopharmaceutical drugs to the patient by injection or oral. Radio meaning the emitted of gamma rays and pharmaceutical represents the compound to which a nuclide is bounded or attached. Unlike CT has the ability to give information about the physiological function of a body system. The radiopharmaceutical often referred to as a nuclide has the ability to emit ga...
Nuclear medicine investigation offers information that is unique including on both function and structure and often inaccessible using other imaging procedures.1¬ Nuclear medicine provides the information specifically and accurately about any disease inside the human body. It gives the information about how the infection of a disease is structured and how it is functioned. All in all, the nuclear medicine technology provides very exclusive information that is unreachable with the other imaging technologies.
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Nuclear Medicine is the use of radioisotopes for diagnosis, treatment, and research. Radioactive chemical tracers emit gamma rays which provides diagnostic information about a person's anatomy and the functioning of specific organs. Radioisotopes are also utilizes in treatments of diseases such as cancer. It is estimated that approximately one in two people in Western countries are likely to experience the benefits of nuclear medicine in their lifetime.
A radioisotope is an isotope that emits radiation as it has nuclear instability(Prostate Cancer; Fusion imaging helps target greater doses of radiation).Those who are not too familiar with radioisotopes may think their use is for harmful radiation, nuclear weapons, and the possibility of turning into a giant, raging, green monster. However, there are much more positive uses for radioisotopes. There have been many medical advances thanks to the benefit and practice of radioisotopes in nuclear medicine. These advances have been able to diagnose and treat a variety of diseases.
Nordqvist, C. (2009, June 1). What Is Bursitis? What Causes Bursitis? Retrieved from medicalnewstoday.com: http://www.medicalnewstoday.com/articles/152120.php