Download Medical Imaging (Fluoroscopy)

In the name of God
Medical Imaging
(Fluoroscopy)
By: Payam Khoshkenar (8533043)
What is Fluoroscopy?
Fluoroscopy is an imaging technique commonly
used by physicians to obtain real-time images of the
internal structures of a patient through the use of a
fluoroscope. In other word, fluoroscopy is a
technique for obtaining “live” (X-Ray) images of a
living patient – it’s like an x-ray TV camera.
Fluoroscopy is a type of medic al imaging that
shows a continuous x-ray images on a monitor,
much like an x-ray movie.
Thus, the common name for production of real-time
images.
History
The beginning of fluoroscopy can be tracked
back to 8 November 1895 when Wilhelm
Roentgen noticed the barium platinocyanide
screen fluorescing as a result of being
exposed to what he would later call x-rays.
Within months of this discovery, the first
fluoroscopes were created.
Historically, fluoroscopy was done the first
time by W.C. Roentgen when he first
discovered the new kind of rays in 1895.
For medical purposes the first fluoroscopy
units were used as early as 1896.
Kinds of Fluoroscopes
Early fluoroscopes were simply cardboard
funnels, open at narrow end for the eyes of
the observer, while the wide end was closed
with a thin cardboard piece that had been
coated on the inside with a layer of
fluorescent metal salt.
Early Fluoroscopes
The fluoroscopic image obtained in this way is
rather faint. Thomas Edison quickly
discovered that calcuim tungstate screens
produced brighter images and is credited with
designing and producing the first
commercially available fluoroscope.
In its infancy, many incorrectly predicted that
the moving images from fluoroscopy would
completely replace the still x-ray radiographs,
but the superior diagnostic quality of the
earlier radiographs prevented this from
occuring.
Different parts of fluoroscopy equipments
• A patient table
• X-ray generator
• X-ray tube
• Image intensifier
• Flat panel detectors
• Image display system
The first fluoroscopes consisted of and x-ray
source and fluorescent screen between which
the patient would be placed. As the x-rays
pass through the patient, they are attenuated
by varying amounts as they interact with the
different internal structures of the body,
casting a shadow of the structures on the
fluorescent screen.
Fluoroscopy revolution
The fluoroscopic technique was revolutionized
when the image intensifier was introduced.
The invention of x-ray image intensifiers in the
1950s allowed the image on the screen to be
visible under normal lighting conditions, as
well as providing the option of recording the
images with a conventional camera.
Subsequent improvements included the
coupling of, at first, video cameras and, later,
CCD(charge-coupled device) cameras to
permit recording of moving images and
electronic storage of still images.
The fluoroscopy units were equipped with a
fluorescent screen consisting of copper
activated zinc cadmium sulphide that emitted
light in the yellow-green part of the visible
spectrum.
Modern image intensifiers no longer use a
separate fluorescent screen. Instead, a
caesium iodide phosphor is deposited directly
on the photocathode of the intensifier tube.
On a typical general purpose system, the
output image is approximately 105 times
brighter that the input image.
Flat-panel detectors
The introduction of flat-panel detectors allows
for the replacement of the image intensifiers
in fluoroscope design. Flat-panel detectors
offer increased sensitivity to x-rays, and
therefore have the potential to reduce patient
radiation dose.
Resolution is also improved and motion
blurring is reduced.
Contrast ratio is also improved.
Operation
The fluoroscope is maneuvered in such a way
that the patient, and anatomical area of
interest, is positioned between the x-ray tube
and the image intensifier. The operator uses
the control console to set imaging
parameters.
The intensity of the x-rays is controlled with
the milliamperage (mA) setting and the
energy and intensity of the x-rays are
controlled with the peak kilovoltage (kVp)
setting.
A typical fluoroscopy image setting is 70 kVp
at 2 mA.
Viewing the output film
• Viewing with eyes
• Viewing with TV camera
Brightness control
• Automatic Gain Control (AGC)
• Automatic Brightness Control (ABC)
The Brightness gain comprises a flux gain
and minification gain.
Flux gain is amplification of photon number
Minification gain is concentration of photons
from a large input screen onto a small output
screen
Recording of fluoroscopy film
The fluoroscopy films are recorded by photospot cameras.
Due to the limited light produced from the
fluorescent screens, early radiologists were
required to sit in a darkened room.
Red adaptation goggles were developed by
Wilhelm Trendelenburg in 1916 to address the
problem of dark adaptation of the eyes.
Risks
Because fluoroscopy involves the use of xrays, a form of ionizing radiation, all
fluoroscopic procedures pose a potential
health risk to the patient.
Continuous fluoroscopy for long periods can
deliver a significant radiation dose. Therefore
most systems have a pulsed fluoroscopy
mode.
Uses of fluoroscopy
• Fluoroscopy is used to diagnose or treat patients
by displaying the movement of a body part or of an
instrument or dye (contrast agent) through the body.
• Fluoroscopy, as an imaging tool, enables
physicians to look at many body systems, including
the skeletal, digestive, urinary, respiratory, and
reproductive systems.
• Fluoroscopy may be perform to evaluate specific
areas of the body, including the bones, muscles and
joints, as well as solid organs such as the heart,
lung, or kidneys.
Fluoroscopy is used in many types of examinations
and procedures. Some examples include:
• Barium x-rays and enemas (BE)
• Catheter insertion
• Orthopedic surgery
• Locating foreign bodies
• Viscosupplementation injection
• Image-guided anesthetic injection
Barium x-rays and enemas (BE)
In barium x-rays, fluoroscopy used alone
allows the physician to see the movement of
the intestines and the barium moves through
them.
Catheter insertion
In cardiac catheterization, fluoroscopy is
added to enable the physician to see the flow
of blood through the coronary arteries in order
to evaluate the presence of arterial blockages.
Also is used in intravenous catheterization.
Orthopedic surgery
To view fractures and fracture treatments that
is minimally invasive procedure used to treat
fractures of the vertebrae of the spine.
Viscosupplementation injection
A procedure in which a liquid substance that
acts as a cartilage replacement or supplement
is injected into the knee joint
Locating foreign bodies
• Placement of a PICC (peripherally inserted
central catheter)
• Placement of a weighted feeding tube (e.g.
Dobhoff) into the duodenum after previous
attempts without fluoroscopy have failed
• Implantation of cardiac rhythm management
devices (pacemakers, implantable
cardioverter defibrillators)
Thanks for your attention
Refrences:
www.spinuniverse.com
www.acadiana imaging.com
www.optimalpacing.com
www.msn.com
www.wikipedia.com