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Medical Imaging
• X-ray
• Fluoroscopy
• Computerized Tomography
(CT Scan)
• Positron Emission Tomography
(PET Scan)
• Ultrasound
• Magnetic Resonance Imaging (MRI)
• Biophotonics
X-RAYS
X-ray
source

(x-ray attenuation)
OPAQUE:
Bone, Metals, Iodinated contrast
agents
Shadow
X-Rays – high energy photons
• Absorbed by denser tissues (attenuated) to
produce a lighter image on the film
(radiograph)
• Can be used to diagnose some cancers,
respiratory and cardiovascular diseases such
as enlargement of the heart and structure of
blood vessels
• Dentists use to determine health of teeth and
jaw
• The high energy radiation of x-rays can cause
mutations to DNA
Chest X-Ray
X-Ray of a murder victim killed with 30 nails
Normal Hand X-Ray
Rheumatoid Arthritis Hand X-Ray
Knee Joint X-Ray
Broken Neck X-Ray
Swollowed Scissors X-Ray
X-Ray Photobomb...
This is why high heels hurt your feet!
Fluoroscopy – uses a continuous beam of
X-rays to view a radioactive contrast agent
• The most commonly used x-ray dye is barium sulfate,
a white-chalky substance.
• Fluoroscopic X-Ray images the gastro-intestinal
system and blood vessels of the brain and heart
• Images of the opaque dye travelling through the
arteries to locate a blockage is called an angiogram
• The advantage of Fluoroscopic x-ray over
conventional x-ray is that you can view in real time on
a television monitor the image
• This means that movement of the peristalsis and
normal function of the body's systems can be
captured and recorded on videotape
• Because fluoroscopy involves the use of x-rays,
ionizing radiation, all fluoroscopic procedures pose
some health risks.
Barium Fluoroscopy
Compare the image of the normal heart on the LT. with the image on
the Rt.. In the Rt. image you see a patient with congestive heart
failure whose heart has lost its ability to pump blood efficiently. The
heart on the Rt. significantly enlarged, a key indicator of heart failure.
Fluoroscopy X-Ray – Dog Neck and Shoulder
Computerized Tomography (CT)
X-ray
source
x,y)
(x-ray attenuation)
Collect projections at all angles
Digital Reconstruction on a computer
Shadow
CT –SCAN – uses X-rays as well
• X-rays are directed all around the patient
from various angles to create a 3-D image of
the tissues
• Detailed, cross-sectional images are used to
diagnose cancer, abnormalities of skeletal
tissue and the circulatory system
• Relatively quick and painless
CT Scan - Heart
CT Scan – 3D of various views of the Heart
Nuclear medicine (PET Scans)
PET = Positron Emission Tomography
• After the patient is given a radioisotope that emits positrons
(positively charged electrons), PET scanning is used to detect
cancer, as well as a number of cardiovascular and neurological
abnormalities (such as Alzheimer’s and epilepsy).
• Cancer cells, for example, have a much higher level of
metabolic activity than normal cells. Cancer cells therefore
‘consume’ radioactive isotopes (such as radioactive iodine).
PET scanning detects that increased metabolic rate and can
therefore:
• Show whether a tumor is benign (non-cancerous) or malignant
(cancerous)
• Help doctors determine the extent of disease
• Illustrate metastatic disease (spread)
• Help doctors evaluate the effectiveness of chemotherapy
PET Scan – Tumours before
Chemotherapy (Lt.) and after (Rt.)
PET Scan
PET Scan - cancer of the head and neck with
extensive metastatic disease
PET Scans can detect metabolic changes in different tissue types
• Certain neurological disorders have characteristic
metabolic changes. These are readily apparent on
PET images. Alzheimer’s disease, for example, has a
unique appearance on PET scans. This appearance
can differentiate Alzheimer’s from other forms of
dementia, and give the patient earlier access to
appropriate treatments.
• In cardiovascular disease, PET images provide
information about blood flow and the presence of
damaged muscle tissue. This information is key to
planning appropriate treatments and disease
management.
PET scan images superimposed on MRI scan images shows a
healthy medical student's brain function when performing
arithmetical tasks at the same time as being exposed to speech.
PET Scan of the Brain of a 20 yr old man (Lt.)
vs 80 yr old man (Rt.)
Your Brain on Drugs (the red areas indicate
glucose uptake (= metabolism and brain function))
Ultrasound
r(x,y,z)
acoustic reflectivity
Propagate sound pulse and receive reflection
Compute position and velocity of reflection (Doppler shift)
QuickTime™ and a
Microsoft Video 1 decompressor
are needed to see this picture.
2D
3D
Ultrasound of a normal human uterus
Ultrasound of Human gall bladders
Magnetic Resonance Imaging (MRI)
The MRI provides excellent differentiation between
various types of soft tissues compared to radiographs
(X-rays and CT).
MRI can be used to visualize the brain, heart, liver,
spinal cord, eyes, nasal cavities, inner ears, joints,
and bones without injecting any contrast material.
It is the most sensitive imaging for early disease
detection of the above tissues and for cancer
diagnosis.
A functional MRI (fMRI) allows us to view the images in
real time on a television monitor
How the MRI works:
• Uses powerful magnets and radiowaves as a
non-invasive imaging technique with no
damaging radiation
• These magnetic and radiowave fields
influence the behaviour of hydrogen nuclei in
water
• The behaviour of these hydrogen nuclei is
detected and analysed by computers that
generate detailed images of the tissues
MRI Systems
$2-3 million
MRI – Section through head
MRI – Cross Section of Head
f-MRI – Where in the brain is hand/eye
coordination?
MRI – Neck Region
MRI – Knee Joint
Mammogram (X-Ray) vs MRI
MRI of Blood Flow in the Brain
MRI – Dog Skull
Biophotonics
• Biophotonics offers the ability to diagnose and
monitor disease nearly at the speed of light, based on
the way light interacts with tissue and is scattered by
the molecules and atoms.
• With biophotonics, healthcare professionals will know
in moments what before took hours or days with
traditional tests, enabling treatment to begin
immediately.
• Since normal tissue scatters light differently than
abnormal tissues, Biophotonics also allows for
studying human tissue at the cellular and molecular
level for the purposes of detecting, diagnosing and
monitoring disease.
Exposure of chicken embryos to laser light to detect changed
in development and stages of cell specialization/differentiation
Imaging cerebral blood flow in mice using
light with skull left intact