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
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<http://science.howstuffworks.com/x-ray1.htm>.
Hill, J. "CT Scans." Chemistry Explained.
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<http://www.chemistryexplained.com/Co-Di/CT-Scans.html>.
Newman, Phil. "Electromagnetic Spectrum." Goddard
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<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
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-légumes <3
