Continuing with our medical theme, I present to you: CAT scans

Overview

A computed axial tomograph, more commonly known as a CAT scan, is a cross sectional image created by using a wedge shaped beam of x-rays, aimed at an array of detectors, to create a series of images taken from different angles around the body (Hill). Information from each angle is communicated to a computer, which calculates how the images fit together, creating a “slice”, or cross-sectional image, every revolution (“CAT Scans…”). A CAT scan is the exact same as a CT scan, but CT scan is the more commonly used term in modern medicine. The CAT scan was invented in the late 1960s by British engineer Sir Godfrey Newbold Hounsfield, and led to him winning the Nobel Prize for Medicine and Physiology in 1979 (Hill). CAT scans use x-rays, a powerful form of electromagnetism, to create images. X-rays are comprised of photons, which are similar to visible light photons, yet have much more energy. This high energy level makes it so x-ray beams pass through most soft tissue in the body, since they have much more than the energy required for an electron in these tissues to move up an orbital. But, also due to this high energy level, x-ray photons can sometimes knock an electron away from an atom altogether, with some energy going towards removing the electron, and the rest sending the electron flying through space (Harris).  Larger atoms, like the calcium atoms in bones, are more likely to absorb a photon this way (Harris). This is because larger atoms have greater differences in energy, close to that of an x-ray photon, between orbitals, compared with the relatively smaller differences in energy in a smaller atom, like those found in soft tissues (Harris). This is why contrast materials, or “dyes” may be used in CAT scan procedures. The most common dyes used are iodine-based dyes, administered intravenously, and barium sulfate compounds, administered orally (“Contrast…”). Iodine-based dyes are used to enhance images of organs such as the heart, lungs, liver, arteries and muscles, whereas barium sulfate compounds are used for images of the stomach, intestines and esophagus (“Contrast…”). When these dyes are present in tissues, they increase the density of the tissue where the dye is absorbed, limiting the ability of x-rays to pass through (“Contrast…”). This allows for soft tissues to be seen more clearly in CAT scans.  Different tissues absorb dyes differently, allowing for differentiation between the tissues seen in the images.

Benefits and Risks

            The CAT scan was a breakthrough invention, due to its many benefits to medicine and medical diagnosis. This technology is extremely useful in monitoring tumors before and after treatment, as a CAT scan can show the size, shape, location and blood vessels that lead into a tumor, without any surgery. They can also be used to guide needles for biopsies, or into tumors for certain cancer treatments, such as radiofrequency ablation, which uses heat to destroy cancerous tumors ("Computed Tomography Scan."). This is to make the procedures as minimally invasive as possible, which can lead to faster recovery times and fewer complications. These scans can also be used to diagnose and monitor other abdominal conditions, such as coronary artery disease, spinal disease, and ulcerative colitis  "Computed Tomography Scan of the…”). Although CAT scans are very beneficial, there are multiple downsides to the procedure. CAT scans can be very expensive, and may not be covered by all insurance plans. For example, the average cost for a CT scan of the heart and pelvis in Arizona is $4,465, not including physician’s fees (“Average…”). Another downside of this technology is the potential for exposure to radiation. Being exposed to the levels of radiation emitted in a CAT scan, which is 150-1,100 times that of a conventional x-ray, and equal a year’s worth of radiation from the world around us, can cause an increase in the risk of cancer (“How much…”). This is because x-ray beams can damage DNA, creating mutations that initiate the formation of tumors (“How much…”). Lastly, severe reactions to the contrast dyes are possible, leading to low blood pressure and trouble breathing. In some patients, kidney problems were also reported ("Computed Tomography Scan."). That being said, when this is all taken into consideration, the benefits far outweigh the risks. CAT scans reduce, and can eliminate, the need for invasive surgeries, and help evaluate, diagnose, and plan treatment for many conditions ("Computed Tomography (CT)."). The chance of reactions to dyes is very small, and it is much more important to get help for current, possibly life threatening, conditions than it is to worry about a small possibility in the future.

Related Career

            A career that has links to this unit is a radiologist. Radiologists are a type of physician who used different technologies, such as CAT scans, MRIs and PET scans, in order to analyze tissues and diagnose injuries and illnesses in a non-invasive way (Sapko). They also use these technologies to treat conditions, by using computer-generated “maps” to guide instruments to perform procedures such as inserting catheters and removing malignant tissue (Sapko). Radiology is a rapidly advancing field, and although most radiologists typically work in hospitals and at outpatient diagnostic centres, there are many other opportunities. Some radiologists are in a field called telemedicine, where they can work anywhere in the world, as long as they have access to a computer, high resolution monitor an Internet connection (Sapko). These telemedicine radiologists help analyze scans, and are beneficial to emergency departments, especially after hours (Sapko). Overall, radiology is a very diverse and interesting field, which uses applications of analytical chemistry, along with biology, physics and mathematics.

Works Cited

"Average Cost of CT Scans." JCL.com. John C. Lincoln Heath Network, n.d. Web. 18 Oct. 2014. <http://www.jcl.com/hospitals/average-pricing-information/ct-scans>.

"CAT Scans." Meditech. Meditech Group, 2012. Web. 18 Oct. 2014. <http%3A%2F%2Fwww.meditech.cn%2Fmeditech-edu%2Finfo6.asp>.

"Computed Tomography (CT)." U.S. Food and Drug Administration. U.S. Department of Health and Human Services, 08 Aug. 2014. Web. 17 Oct. 2014. <http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/MedicalX-Rays/ucm115317.htm>.

"Computed Tomography Scan." Cancer.org. American Cancer Society, 09 Aug. 2013. Web. 18 Oct. 2014. <http://www.cancer.org/treatment/understandingyourdiagnosis/examsandtestdescriptions/imagingradiologytests/imaging-radiology-tests-ct>.

 "Computed Tomography Scan of the Abdomen." Health Library. Johns Hopkins Medicine School, n.d. Web. 18 Oct. 2014. <http%3A%2F%2Fwww.hopkinsmedicine.org%2Fhealthlibrary%2Ftest_procedures%2Fgastroenterology%2Fcomputed_tomography_ct_or_cat_scan_of_the_abdomen_92%2CP07690%2F>.

"Contrast Materials." Radiologyinfo.org. Radiological Society of North America, 07 Mar. 2013. Web. 18 Oct. 2014. <http://www.radiologyinfo.org/en/safety/index.cfm?pg=sfty_contrast>.

"CT Scan- Abdomen and Pelvis." Radiologyinfo.org. Radiological Society of North America, 13 Aug. 2014. Web. 18 Oct. 2014. <http%3A%2F%2Fwww.radiologyinfo.org%2Fen%2Fsafety%2Findex.cfm%3Fpg%3Dsfty_contrast>.

Harris, Tom. "How X-Rays Work." HowStuffWorks. HowStuffWorks.com, 26 Mar. 2002. Web. 15 Oct. 2014. <http://science.howstuffworks.com/x-ray1.htm>.

Hill, J. "CT Scans." Chemistry Explained. Advameg Inc, n.d. Web. 18 Oct. 2014. <http://www.chemistryexplained.com/Co-Di/CT-Scans.html>.

Newman, Phil. "Electromagnetic Spectrum." Goddard Space Flight Centre. NASA, 14 Feb. 2014. Web. 18 Oct. 2014. <http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html>.

Sapko, Michael, M.D. "How to Become a Radiologist." Careers in Health. InnerBody, n.d. Web. 15 Oct. 2014. <http://www.innerbody.com/careers-in-health/how-to-become-a-radiologist.html>.

Storrs, Carina. "How Much Do CT Scans Increase the Risk of Cancer?" Scientific American. Nature America, 18 June 2013. Web. 18 Oct. 2014. <http://www.scientificamerican.com/article/how-much-ct-scans-increase-risk-cancer/>.

-légumes <3