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AHM 244 Introduction
to Imaging
Principles of Radiology
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X-rays (discovered late 19th century)
Computed Tomography (CT scan)
Sonography (ultrasound)
Fluoroscopy
Nuclear Medicine – used for diagnostic and
therapeutic procedures
Magnetic Resonance Imaging (MRI)
Positron Emission Tomography (PET)
X-rays
Radiography
 High energy waves that cannot be
seen or felt
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Similar to photographs
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Radiopaque – do not permit
passage of x-rays i.e. bones; show
up on x-ray
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Radiolucent – permit the passage
of x-rays i.e. soft tissue; do not
show up on x-ray
X-rays
Patient Positioning
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Radiation Safety
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Can cause cellular or genetic damage
2-dimensional
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Minimize exposure
Requires 2 exposures 90 degrees to each
other
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Avoid unnecessary exams
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May require multiple positions and views
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Limit area of body exposed
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Review standard positions in handouts and
in text
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Shield sensitive body parts
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Review exam sequencing in text
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Pregnancy status
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http://www.rtstudents.com/radiologypositions.htm
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Workers:
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Use shielding
Wear dosimeter
Diagnostic Procedures
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Mammography –
x-ray examination of the
breast
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Vital adjunct to biopsy
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Performed yearly after
age 40 or sooner with
history or suspicion
Diagnostics cont…
Contrast Studies
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Used to differentiate structures
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Introduced via IV, catheter, orally
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Iodine – blood vessels; if allergic
to shellfish, do not use iodine!
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Barium – intestines and stomach
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Air - Joints
Fluoroscopy
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Use of x-rays to observe
movement within body
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Contrast mediums used such
as barium or iodine
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Blood flow, beating heart,
digestive tract
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Also used to aid in reducing
fractures or implanting
devices such as pacemakers,
stents, etc..
Computed Tomography
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Cross-sectional group of xrays that target a specific site
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Tube circles the patient,
computer analyzes to create
the cross-sectional views
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Done with and without
contrast
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Organs can be viewed from
all angles
CT Cont….
Sonography
Ultrasound
 Non-invasive
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Uses high-frequency sound waves
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Creates cross-sectional still views
or views in real time movement
with help of a computer
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Used for heart function, abdominal
and pelvic structure views and fetal
visualization
Sonography cont…
MRI
Magnetic Resonance Imaging
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Uses high-intensity magnetic fields
(magnets), radio waves and computer
analysis to create cross-sectional images
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Used for central nervous system studies,
joint structure, etc.
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Done with or without contrast
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Claustrophobia is an issue
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Metal implants from surgeries is a
contraindication
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Patient must remove any jewelry and other
metal objects
MRI cont…
Nuclear Medicine
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Small amounts of radionuclides (radioactive
materials) are injected
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These concentrate in specific areas of body
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Computer cameras detect particles and
create an image
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Used to study thyroid, brain, lungs, liver,
spleen, kidney, bone and breast
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Positron Emission Tomography (PET)
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Single Photon Emission Computed
Tomography (SPECT)
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Assists with diagnosis of cellular
abnormalities esp. cancer
Nuclear Medicine cont…
Interventional Radiologic
Procedures
Designed to treat specific disease conditions – helps patients avoid surgeries, lifesaving
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Percutaneous Transluminal Coronary Angioplasty (PTCA) – balloon
angioplasty; used to enlarge lumen of blocked artery
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Laser Angioplasties – use lasers to remove deposits in vessels
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Vascular Stents – plastic or wire tubes inserted into a constricted vessel to
open it; this procedure is guided by fluoroscopy
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Embolizations – artificially stop bleeding from a blood vessel or reduce
blood flow to a diseased area of an organ
PTCA
Laser Angioplasty
Vascular Stent
Embolization
Radiation Therapy
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Major force in fight against cancer
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Uses high-energy radiation to kill cancer
cells
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Used in conjunction with surgery and
chemotherapy (drug therapy)
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Precise and carefully planned by radiation
oncologist (MD specializing in radiology)
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Each treatment must be identical to a
specifically defined area of the body
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Side effects: weight loss, hair loss, loss of
appetite, skin changes, digestive system
disturbances
Patient Education & Preparation
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Help alleviate anxiety
Calm fears
Explain procedures
Explain preparation – different for each test
from no prep to liquid diet and laxatives
Assist as needed
Post procedure education
Handling and Storage of
Radiographic Films
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Protect unexposed films from extremes of temperature and light
Exposed films kept in protective sleeves
Maintain patient confidentiality per HIPAA
Correct labeling of patient films
Films obtained on site remain part of patient record – films belong to the site that
performed the procedure; can be signed out by patient or sent by courier to specialist
or PCP
Digital films can be kept in the EMR
Written summary sent to providers of patient care
Teleradiology – computed imaging and information systems; many places use (PACS)
Picture Archiving and Communication System to store films on computers
 Can outsource films this way to other countries even for a radiologist to read films;
consults with specialists from around the world is possible with this system and in
rural areas