Download Remote Sensing - Rocky View Schools

Remote Sensing
I processed the images on Yellow stone National Park. First they give you a little bit of
information on what had happened and what the two satellite images meant. It took me a
little while to figure out how to calculate the answers to the questions using pixels but I
found relief when it said I had the answers right. After you submit your answers and their
right the web site brings you to a page with some history and back ground information on
this event because it actually did occur and I though that was pretty interesting that they
would include some information on that. Another thing that I though was interesting was
that you get to play a role like in this case a firer ranger that has to report to the media.
This is a very useful technique to have and I am glad that I was able to experience it.
Technology
CT
Advantage
Disadvantages
CT scans use a series of X – ray
beams passed through the head.
The images are then developed on
sensitive film.
This method creates
cross sectional
images of the brain
and shows the
structures of the
brain, but not its
function.
- The principle
advantage of CT is than
it non destructively
provides quantitative
densitometric images of
thin cross sections
through an object.
A scanner detects radioactive
material that is injected or inhaled
to produce an image of the brain.
Commonly used radioactively –
labelled material included oxygen,
fluorine, carbon, and nitrogen.
When this material gets into the
blood stream, it goes to areas of
the brain that use it. So oxygen and
glucose accumulate in brain areas
that are metabolically active.
When the radioactive material
breaks down, it gives off neutron
and positron. When a positron hits
an electron, both are destroyed and
gamma rays are released. Gamma
ray detections record the brain area
where the gamma rays are emitted.
MRI uses the detection of radio
frequency signals produced by
displaced radio waves in a
magnetic field.
This method provides
a functional view of
the brain.
- Provides an image of
brain activity
- Potential object for
examination must be
small enough to be
accommodated by the
handling system of the
CT equipment available
to the user and must be
radiometrically
translucent at the X-ray
energies employed by
that particular system.
- Expensive to use
- Radioactive material is
used
It provides an
anatomical view of
the brain.
fMRI
It is based on differences in
magnetic resonance of certain
atomic nuclei in areas of neuronal
activity.
- Expensive to use.
- Cannot be used on
patients with metallic
devices, like
pacemakers.
- Cannot be used on
uncooperative patients
because the patient must
lie still.
- Cannot be used on
patients who are
claustrophobic.
Poor temporal
resolution, susceptible
to movement.
SPECT
Similar to PET, this imaging
procedure also uses radioactivity
tracers and a scanner to read data
that a computer uses to construct
two or three dimensional images of
active brain regions.
FunctionalMRI
detect changes in
blood flow in
particular areas of the
brain. It provides
both an anatomical
and a functional view
of the brain
This method provides
a functional view of
the brain.
- No X – rays or
radioactive material is
used.
- Provides a detailed
view of the brain in
different dimensions
- Safe, painless, noninvasive
- No special preparation
(except the removal of
metal objects) from
patients.
Non – invasive, non –
toxic, best special
resolution, cheaper than
PET, structural and
functioning imaging.
- Because SPECT
tracers are longer
lasting, they do not
require an onsite
cyclotron to produce
them.
- Require les technical
staff and medical staff
than PET.
- Less expensive than
PET.
EEG
Electroencephalography uses
electrodes placed on the scalp to
detect and measure patterns of
electrical activity emanating from
the brain.
- SPECT tracers are
more limited than PET
tracers in the kinds of
brain activity they can
monitor.
- SPECT tracers
deteriorate more slowly
than many PET tracers
meaning SPECT studies
require longer test and
retest periods than PET
studies do.
- Provides less spatial
resolution than fMRI
and PET do.
PET
MRI
How it works
What it does
EEG can determine
the relative strengths
and positions of
electrical activity in
different brain
regions.
- The speed it can
record complex patterns
of neural activity
occurring within
fractions of a second
after stimulus has been
administered.
MEG
A technique for recording
electrical signals from the brain
based on changes in magnetic
fields.
Records electrical
signals from the brain
- Non – invasive
- Superior localization
to EEG
- Subject cannot move
during recording
- very expensive