Download X-Ray imaging Used in many different ways in medical diagnosis. A

Medical Imaging
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X-rays
CT scans
MRIs
Ultrasounds
PET scans
X-Ray Imaging
* Radiation passes through the
body part & strikes a sheet of
sensitive film
* X-rays penetrate tissues varyingly,
according to the tissue’s composition
Example:
* Calcium rich bone restricts radiation  Resulting in
white images on the X-ray film
* Air filled lungs allow nearly all X-rays to strike the
film, resulting in a black film image
X-RAY Examples
X-Ray Website
CT or CAT scan:
CT (CAT) (Computerized Axial Tomography) scanner
* Special kind of X-ray machine
* Instead of sending out a single X-ray through your
body, as with ordinary X-rays, beams of rays are sent
simultaneously from different angles
How does a CT scanner work?
Beams that have passed through less dense tissue
(lungs) will be stronger, whereas, beams that have
passed through denser tissue (bone) will be weaker
A computer then uses this information to work out
the relative density of the tissues examined. Each set
of measurements made by the scanner is, in effect, a
cross-section through the body
CT Website
CT scan examples
PET Scan Imaging
• PET = Positron Emission Tomography (PET) scan
– Illustrates how the organs/tissues inside your body are
actually functioning
– Radioactive chemical (radiotracer) is injected into an arm
vein
• Tracer travels through the body and is absorbed by the
organ/tissues
– PET machine detects and records the energy given off by
the tracer and a computer converts this energy into 3D
pictures
– A physician can then look at cross-sectional images of the
body organ from any angle in order to detect any
functional problems
PET Scans Detect
• How effective a patient’s treatment plan is, allowing the course
of care to be adjusted, if necessary
• Cancer
• Heart problems
– Coronary artery disease
– Damage to the heart following a heart attack
• Brain disorders
– Brain tumors, memory disorders, seizures
• Other central nervous system disorders as well as blood flow,
oxygen use, and glucose metabolism
• Cellular level metabolic changes occurring in an organ or tissue
– Unlike a CT or MRI  which only detects the changes later, as the
disease begins to cause changes in the structure of organs or tissues
PET Scan Website
PET Imaging Examples
MRI Scans
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MRI = Magnetic Resonance Imaging
• Use magnetic and radio waves
• Meaning, there is no exposure to X-rays or any other
damaging forms of radiation
• Radio waves, 10,000-30,000x stronger than the
magnetic field of the earth, are sent through the
body, forcing the body's atoms’ nuclei (hydrogen
atoms from water) into a different position, and send
out radio waves of their own. The scanner picks up
these signals and a computer turns them into a
picture.
MRIs Provide
• Pictures of almost all the different types of tissues in the body
• Tissues
– Least number of hydrogen atoms, (bones), turn out dark
– Many hydrogen atoms, (fatty tissue), look much brighter
• Clear pictures of the brain & spinal cord (even when
surrounded by bone)
• The best technique for
– Finding tumors in the brain, or abnormal tissue that occurs if someone
has MS, bleeding in the brain, or find out if the brain tissue has
suffered lack of oxygen, after a stroke
• Pictures/information in regards to
– Heart defects, as well as, changes in the thickness of the heart muscle
following a heart attack
– Joints, spine and sometimes the soft parts of your body, such as the
liver, kidneys and spleen
MRI Examples
MRI Website
Ultrasounds
• Use high-frequency sound waves
• Reflected sound wave echoes are recorded and displayed
as a real-time visual image. No ionizing radiation (X-ray) is
involved
• Obstetric ultrasound
– Refers to the specialized use of sound waves to visualize and thus
determine the condition of a pregnant woman and her embryo or
fetus
• Useful way of examining many of the body's internal
organs, including but not limited to the heart, liver,
gallbladder, spleen, pancreas, kidneys and bladder
• Ultrasound images are captured in real time, thus they can
show movement of internal tissues and organs and enable
physicians to see blood flow and heart valve functions. This
can help to diagnose a variety of heart conditions and to
assess damage after a heart attack or other illness
Ultrasound Website
Obstetric Ultrasound