Download Chapter 3.1 Check and Reflect Answers Key Concept Review

Chapter 3.1 Check and Reflect Answers
Key Concept Review
1. Limitations of the use of X-rays include the damage to DNA caused
by the radiation, and the tendency of X-rays to penetrate soft tissues,
which cannot be seen on an X-ray.
2. Students’ answers may vary.
• X-rays are used to image bones for breaks, to look at teeth for
cavities, to see abnormalities in some organs, and to check the
structure of blood vessels.
• Fluoroscopy uses X-rays to produce images showing movement
of organs. Patients may have to drink a contrast liquid, such as
barium or iodine, to help see the organ.
• Ultrasound uses high-frequency sound waves to produce images
of tissues and organs. It is also used in pregnancy to check the health
and development of the fetus.
• Computed tomography (CT) uses X-rays to create a 3-D image
from a series of images taken at different angles. It is used to
diagnose cancer and vascular disease, and to look for abnormalities
in the skeletal system.
• Magnetic resonance imaging (MRI) uses powerful magnets and
radio waves to produce detailed images of the body. It is used to
image the brain, heart, liver, soft tissues, and the interior of bones. It
can also be used to diagnose cancer, brain diseases, and
cardiovascular conditions.
• Nuclear medicine uses radioactive isotopes to provide images of
how tissues and organs function.
• Positron emission tomography (PET) is a type of nuclear
medicine that is used to detect cancer in tissues or to examine the
effects of cancer treatments. It can also be used to detect some brain
disorders.
• Biophotonics uses interactions of light with cells and tissues to
look for and to treat abnormalities in organs. For example, a thin
tube light and camera can be used to look at the stomach and
intestines.
3. An angiogram is a fluoroscopy technique that uses a continuous beam
of X-rays to produce images showing how the blood flows through
the blood vessels. A dye is added to allow doctors to see blood flow.
This technique helps to show any narrowing of the arteries.
4. X-rays are used to kill cancer cells. A beam of X-rays is directed at a
tumour to reduce damage to neighbouring normal cells. The X-rays
damage the DNA to kill the cancer cell or prevent the cell from
multiplying.
5. A radiologist is a doctor who has been trained to read and interpret
radiographs to diagnose disease or problems.
6. A chest radiograph shows abnormalities in the lungs, the size of the
heart, and the structure of associated blood vessels.
7. Ultrasound is not an appropriate choice for imaging the bowel
because the images can be blurred by air or other gases.
8. Radioactive iodine is used to treat thyroid cancer because iodine is
used by the thyroid. When radioactive iodine is taken up by the
thyroid, the radiation of the iodine kills the cancer cells. After a few
days, iodine decays to a non-radioactive element and is excreted.
9. (a) Ultrasound imaging is used to monitor the position and
development of a fetus.
(b) Ultrasound is used because it is safe and does not cause harm to
the fetus. Ultrasound uses high-frequency sound waves to
produce images.
10. Biophotonics is used to examine the digestive tract through a
gastrointestinal endoscopy or a colonoscopy. It is also used to remove
gallbladders and repair knees.
11. The CT scan forms a three-dimensional picture of the body. It is used
to image bone, soft tissue, and blood vessels at the same time. The
MRI shows detailed pictures of the brain and surrounding nerve
tissues.
Connect Your Understanding
12. Students’ answers may vary. Since the doctor suggests there is a
problem in the circulatory system, the following medical imaging
tests would be appropriate:
• X-rays to provide a chest radiograph to see the size of the heart and
associated blood vessels
• fluoroscopy to study the blood vessels of the heart and a coronary
angiogram to show the flow of blood through arteries
• echocardiogram (type of ultrasound) to look for abnormalities in
the heart or blood vessels
• CT scan of blood vessels as well as the skeleton and soft tissue to
produce a three-dimensional image
• MRI to diagnose certain cardiovascular conditions
• PET scan to look for heart disease
13. Ultrasound is not a good imaging tool for diagnosing bone cancer
because the sound waves cannot penetrate bones.
14. Bones appear white on a radiograph because they absorb X-rays.
15. Since X-rays can damage cell DNA, parts of the body that are not
being imaged are covered by a protective lead apron.
16. Students’ answers may vary. Criteria to be considered when deciding
on the type of medical imaging to use includes the part of the body to
be imaged and the type of imaging tests that are available. For
example, some imaging techniques work well with bones, while
others show soft tissues. Some provide moving images that can help
show function, while others provide a three-dimensional view. In
addition, not all techniques are available in all communities.
17. Students’ answers may vary. People do not receive medical imaging
as a form of preventative medicine because it is very expensive in
terms of the equipment needed and the cost of running a test. Medical
imaging technology also requires trained technicians and qualified
doctors to produce, read, and interpret the images. Some communities
do not provide certain types of medical imaging technology. Doctors
also need to know which test is appropriate.
18. Diagnostic imaging techniques allow for the study of the function of
and changes to internal organs and organ systems of living organisms
without requiring surgery.
19. The cost of medical technology means that some consumers do not
have a wide choice of tests available. For example, for those who live
in rural areas, many expensive imaging techniques may not be
available. Smaller communities may not be able to afford the trained
technicians and doctors needed to interpret the images, in addition to
the cost of the equipment and its maintenance.
Reflection
20. Students’ answers will vary depending on their interests.