Diagnostic Imaging

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Chapter 27

• Diagnostic Imaging

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Principles of Radiology

• Commonly used diagnostic and therapeutic
  procedures
• X-ray imaging
• Computed tomography scans
• Sonography
• Magnetic resonance imaging
• Nuclear medicine

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X-rays

• High-energy waves that cannot be seen, heard,
  felt, tasted, or smelled
• Have the ability to penetrate the human body
• Penetrating waves create two-dimensional
  shadowlike images on film

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X-rays Machines

• Sophisticated and technologically advanced
• Many work with computers to produce digital
  images
• Fluoroscopic units are capable of visualizing
  motion with body

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Outpatient X-rays

• Some medical offices have on-site x-ray equipment
• Medical assistant may be permitted to take and
  process simple radiographs

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Checkpoint Question 1

• What are x-rays?

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Answer

• X-rays are high-energy waves that travel at the
  speed of light. X-rays can penetrate fairly dense
  objects, such as the human body. They cannot be
  seen, heard, felt, tasted, or smelled.

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Patient Positioning

• X-ray examinations usually require a minimum of
  two exposures taken at 90 to each other
• These angles are basis for standard positioning

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Examination Sequencing

• Most radiographic procedures can be performed in
  any order
• Certain procedures must follow specific sequences
• Patients with gallbladder symptoms
• Barium studies

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Checkpoint Question 2

• Why is it important to schedule a barium enema
  before an upper GI or barium swallow?

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Answer

• Barium enemas involve filling only the large
  intestine with barium. Because the large
  intestine is the last part of the GI tract, this
  barium can be eliminated more quickly. If an
  upper GI examination is performed first, it may
  be days later before barium can be eliminated,
  thus delaying other examinations.

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Radiation Safety

• X-rays have potential to cause cellular or
  genetic damage
• At highest risk
• Pregnant women
• Children
• Reproductive organs of adults

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Radiation Safety Proceduresfor Patients

• Reduce exposure amounts as much as possible
• Avoid unnecessary examinations
• Limit area of body exposed
• Shield sensitive body parts
• Evaluate potential pregnancy status

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Radiation Safety Proceduresfor Clinical Staff

• Limit amount of time exposed to x-rays
• Stay far away from x-rays
• Use available shielding
• Avoid holding patients during exposure
• Wear individual dosimeters
• Ensure proper working condition of equipment

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Diagnostic Procedures

• Routine radiographic examinations
• Named for part of body involved
• Performed for viewing bone structure or
  abnormalities

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Mammography

• Specialized x-ray examination of the breast
• Screening tool for breast cancer
• Breast compressed in specialized device
• Has become vital adjunct to biopsy procedures

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Contrast Media Examinations

• Radiographic contrast media helps differentiate
  between body structures
• Used to evaluate structure and function

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Contrast Media

• Introduced into body in several ways
• Swallowing
• Intravenously
• Through a catheter
• Medical assistant must ensure that patients
  understand preparation instructions

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Checkpoint Question 3

• How do contrast media help in differentiating
  between body structures?

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Answer

• Contrast media help differentiate between body
  structures by artificially changing the
  absorption rate of a particular structure so that
  it can be seen clearly instead of blending in
  with adjacent structures. For example, barium
  sulfate absorbs radiation and shows up as white
  areas on a radiograph.

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Fluoroscopy

• Use x-rays to observe movement within the body
• Barium sulfate through the digestive tract
• Iodinated compounds showing the beating of the
  heart

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Computed Tomography (CT, CAT scan)

• Tomography
• X-ray tube and film move in relation to one
  another, blurring all structures except those in
  focal plane.
• CT uses x-rays from a tube circling the patient,
  analyzed by computers to create cross-sectional
  images

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Sonography (Ultrasound)

• High-frequency sound waves, not x-rays, create
  cross-sectional still or real-time images
• Used to demonstrate heart function or abdominal
  or pelvic structures
• Used in prenatal testing to visualize developing
  fetus

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Magnetic Resonance Imaging (MRI)

• Combination of high-intensity magnetic fields,
  radio waves, and computer analysis creates
  cross-sectional images
• Used to study central nervous system, joint
  structure
• Patient must be prepared for lengthy procedure in
  enclosed machine

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Checkpoint Question 4

• How does fluoroscopy differ from computed
  tomography and sonography?

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Answer

• Fluoroscopy uses x-rays to show movement within
  the body. CT uses a combination of x-rays and
  computers to create cross-sectional images of the
  body. Sonography uses high-frequency sound waves
  to create cross-sectional still or real-time
  (motion) images of the body.

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Interventional Radiologic Procedures

• Designed to treat specific disease conditions
• Percutaneous transluminal coronary angioplasty
• Laser angioplasties
• Vascular stents
• Embolizations

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Checkpoint Question 5

• How could PTCA be a life-saving measure?

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Answer

• PTCA could save a patients life by reopening the
  lumen of a coronary artery to allow sufficient
  blood flow and oxygen to keep the heart muscle
  alive.

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Radiation Therapy

• High-energy radiation is used to destroy cancer
  cells
• Treatments must be planned carefully by
  radiologist
• Most patients have some side effects

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The Medical Assistants Role in Radiologic
Procedures

• Help alleviate anxiety patients feel
• Give patients information about examinations
• Make patients feel comfortable enough to ask
  questions
• Answer questions in terms patient can understand

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Patient Education

• Explain what to expect in simple language, not
  technical medical terms
• Explaining preparations for examinations
• Explain what to do after procedure

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Assisting with Examinations

• Give patient instructions for what clothing to
  remove
• Assist with clothing removal
• Help position patient for the procedure
• Perform specific procedures
• Place film into automatic processor
• Reload new film
• Distribute radiographs and report

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Handling and Storing Radiographic Films

• Unexposed film must be protected from moisture,
  heat, and light
• Store in a cool, dry place, preferably a
  lead-lined box
• Film packets must be opened in a darkroom
• Place film in cassette for use outside of darkroom

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Checkpoint Question 6

• How can the medical assistant help with
  radiologic examinations?

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Answer

• Medical assistants can help with radiologic
  examinations by providing instruction to
  patients, positioning patients, handling x-ray
  film, and distributing or filing radiographs and
  reports. In some states, the medical assistant
  may take simple x-rays.

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Transfer of Radiographic Information

• Radiographic images remain part of permanent
  record
• Digital images saved on disk
• X-ray films belong to site where study was
  performed
• Examining physician or radiologist writes summary
  of the examination
• Medical assistant obtains patients permission to
  have summary sent to office physician

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Teleradiology

• Use of computed imaging and information systems
• Provides new benefits in medicine
• Digital images can be transmitted via telephone
  lines to distant locations
• Allows for consultation with experts on difficult
  cases