Nuclear Medicine
Imaging and the treatment of
Cancer
Gamma photons are the most energetic
photons in the electromagnetic spectrum.
Gamma rays (gamma photons) are emitted
from the nucleus of some unstable
(radioactive) atoms.
Gamma Radiation
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What are the
properties of gamma
radiation?
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Gamma radiation is
very high-energy
ionizing radiation.
Gamma photons have
no mass and no
electrical charge--they
are pure
electromagnetic
energy.
Gamma Radiation
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Because of their high energy, gamma
photons travel at the speed of light and
can cover hundreds to thousands of
meters in air before spending their
energy. They can pass through many
kinds of materials, including human tissue
Gamma Radiation
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What is the difference between
gamma rays and x-rays?
Gamma rays and x-rays, like visible, infrared, and
ultraviolet light, are part of the electromagnetic spectrum.
While gamma rays and x-rays differ in their origin. Gamma
rays originate in the nucleus. X-rays originate in the
electron fields surrounding the nucleus.
Gamma Radiation
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How do we use gamma emitters?
The penetrating power of gamma photons has many
applications. Gamma rays penetrate many materials,
they do not make them radioactive. The three
radionuclides by far most useful are cobalt-60 and
cesium-137 and technetium-99m.
Gamma Radiation
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Uses of Cesium-137:
cancer treatment
Uses of Cobalt-60:
sterilize medical equipment in hospitals
treat cancer
Gamma Radiation
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Uses of Technetium-99m:
TC-99m is the most widely used
radioactive isotope for diagnostic studies.
(Technetium-99m is a shorter half-life
version of technetium-99.) Different
chemical forms are used for brain, bone,
liver, spleen and kidney imaging and also
for blood flow studies.
Radioactive Measurements
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1. Competitive Binding Assays
2. Time Dependent Measurements
3. Radio Nucleotide Imaging
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Gamma Camera – scintillation camera
4. Tomography
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SPECT imaging
PET imaging
1. Competitive Binding Assays
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No radioactive substance is given to the
patient
Blood from a patient is mixed with a
radioactive substance in the laboratory
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Radioimmunoassay
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Thyroid Hormone and Iron Binding Sites most
common.
1. Competitive Binding Assays
2. Time Dependent Measurements
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Radioactive Tracers are to the patient
administered.
Allows the volume of a compartment to be
measured.
Intravenous Pyelogram
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An Intravenous
Pyelogram (IVP)
is an x-ray
examination of
the kidneys,
ureters, and
urinary bladder.
Intravenous Pyelogram
HIDA Scan

This is a test
done to
diagnose
obstruction of
the bile ducts
(for example,
by a gallstone
or a tumor),
disease of the
gallbladder,
and bile leaks.
Cardiac Angiography
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Coronary angiography is
performed to detect
obstruction in the coronary
arteries of the heart. During
the procedure a catheter is
inserted into an artery in your
groin and then threaded
carefully into the heart. The
blood vessels of the heart are
then studied by injection of
contrast media through the
catheter. A rapid succession of
X-rays is taken to view blood
flow.
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The arrow indicates a
blockage in the right
coronary artery.
Cerebral Angiogram
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This image taken before
angioplasty: This patient
had episodes of
weakness, leading to the
angiogram. The
angiogram shows a very
narrowed artery
supplying the right side of
brain. This vessel is
within the skull on the
surface of the brain
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Cerebral angiogram
taken after
angioplasty: The
narrowing is less
severe and the
branches beyond the
narrowing fill better
3. Radionucleotide Imaging
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Image is generated
using radioactive
decay from an organ
Usually a function of
time.
Provide functional
information
3. Radionucleotide Imaging
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Single detectors are
used for thyroid
studies.
3. Radionucleotide Imaging
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Scintillation Camera
Shows two
dimensional data
Studies physiologic
function
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Ventilation-Perfusion
Scan of a lung looking
for a blood clot.
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A bone scan is used to
find bone problems, such
as cancer, infections, or
fractures, to check joint
replacements, and to find
joint problems, such as
arthritis.
A small amount of
injected radioactive
matter (tracer) and a
camera to form an
image.
Bone scan looking for
metastatic bone cancer.
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Looking for fibrous
dysplasia that is a
congenital, nonhereditary skeletal
disorder
Patients are often
asymptomatic. Others
experience pain,
pathologic fractures
and bone deformity
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Imaging of Acute
Osteomyelitis in the
Diabetic Foot
A 65 year old male with a
history of non-insulin
dependent diabetes
mellitus, alcohol abuse,
and severe peripheral
vascular disease
presented with a nonhealing ulcer of the left
first toe.
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This Indium White
Blood Cell Scan
demonstrates areas of
infection in the
abdomen after
surgery for colon
cancer.
4. Tomography
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The fourth class of imaging is the
tomographic reconstruction of body slices.
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Single-photon emission computer tomography
- SPECT scan
Position Emission Tomography – PET scan
SPECT SCANNER
SPECT Imaging
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The use of a brain SPECT scan is based on the
principal of blood flow.
Areas of increased blood flow take up more
Radioactive tracer than areas of less blood flow.
Blood flow in the brain is directly related to brain
activity.
COMMON DISEASES EVALATED BY SPECT
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Attention Deficit Hyperactive Disorder
Autism, Aspergers syndrome
Unipolar and Bipolar Depression
Anxiety states - Panic,
Obsessive-Compulsive Disorder
Epilepsy and Non-epileptic seizure equivalents
Post Traumatic Stress Disorder
Migraine and common headaches
Schizophrenia
Dementia and memory loss- Stroke- Multiple
Sclerosis- Parkinson's Disease
SPECT Image
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Blood flow to the brain is
represented on a color
scale, dark areas have no
flow and bright yellow
areas have good blood
flow.
The dark "butterflyshaped" area in the center
of the brain is normal, but
the dark area on the right
of each picture is the
region of impaired blood
supply (ischemia) that
corresponds to the
patient's acute stroke.
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Prior to t-PA, the
SPECT scan showed a
large area of the brain
that has lost its blood
supply (arrow).
Several hours after
treatment with t-PA, the
blood flow has
dramatically improved,
although there is still a
small area ischemia
(arrow).
PET Scanner
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Normal PET scan of a
heart.
Image of heart which has
had a mycardial infarction.
The arrow points to "dead"
myocardial tissue.
Therefore, the patient will
not benefit from heart
surgery, but may have other
forms of treatment
prescribed.
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PET image showing malignant
breast mass that was not
revealed by conventional
imaging techniques such as
CT, MRI, and mammogram
PET image of same patient
with enlarged left axillary
lymph nodes (indicated by
arrows), which through biopsy
were found to be metastatic.
The whole body scan reveals a
mass in the left breast
(indicated by arrow), that was
malignant and subsequently
removed
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Normal Brain
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Image of the brain of a 9 year
old female with a history of
seizures poorly controlled by
medication. PET imaging
identifies the area (indicated
by the arrows) of the brain
responsible for the seizures.
Through surgical removal of
this area of the brain, the
patient is rendered "seizurefree".
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PET measurements of
cerebral blood flow (CBF)
and oxygen extraction by
the brain (OEF) before
(top row)and after
(bottom row) angioplasty
of a focal severe stenosis
of an artery at the base
of the brain (supraclinoid
internal carotid artery).
65 year old male with brain tumors imaged
here with a PET scan.
Treatment of Cancer
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Radioactivity is very effective in the
treatment of certain cancers.
The choice is basically do you administer
the radiotherapy externally or internally.
External Beam Therapy
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External beam therapy (EBT) is a method for
delivering a beam of high-energy x-rays to the
location of the patient's tumor.
The beam is generated outside the patient and
is targeted at the tumor site.
These x-rays can destroy the cancer cells and
careful treatment planning allows the
surrounding normal tissues to be spared.
These cancers are commonly treated.
 Breast Cancer
 Colorectal Cancer (Bowel Cancer)
 Head and Neck Cancer
 Lung Cancer
 Prostate Cancer
High Energy X-Rays
Linear Particle Accelerator
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Zapping Cancer Proton Beam
Therapy Proves Effective in Targeting
Tumors
Aug. 17, 2004 — A new kind of radiation is proving effective in the
fight against cancer. Proton beam therapy, according to doctors,
zeroes in on tumors with impressive results and without the
devastating side effects of traditional radiation therapy.
"We can shape the beam more accurately, hitting targets with more
precision," said Dr. Jerry Slater, clinical director of Loma Linda's
Proton Therapy Center in Southern California.
"You don't feel any pain," said Ron Leuck, who is being treated for
prostate cancer with the new therapy.
During the treatment, a rotating scaffold three stories high aims
computerized ray guns directly at his tumor.
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Proton Beam Radiotherapy
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This form of external
beam irradiation involves
directing radiation
through the front of the
eye in order to reach the
intraocular tumor.
When compared to lowenergy eye-plaque
radiation therapy, It is
easier to treat tumors
that are surrounding the
optic nerve with protons.
Brachytherapy
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Brachytherapy is where
radioactive seeds or
sources are placed in or
near the tumor itself,
giving a high radiation
dose to the tumor while
reducing the radiation
exposure in the
surrounding healthy
tissues.
The term "brachy" is
Greek for short distance.
Brachytherapy
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Brachytherapy is not new. Throughout this
century, several types and routes of
implantation of radioactive seeds have been
used to treat cancer.
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Radioactive Iodine seeds were widely used
during the 1970s and 1980s.
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Brachytherapy sources can be divided into
permanent and temporary groups.
Permanent sources tend to have lower energy
and shorter half-lives.
The advantage of these lower energies is
enhanced safety.
The disadvantage is that anatomical
adjustments cannot be made once the sources
are placed.
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Currently, temporary
implants consist
primarily of 192Ir and
137Cs.
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Currently, the 2 most
common permanent
radioactive sources for
brachytherapy seeds are
125I and 103Pd.
The lower the energy
emitted by the photons,
the higher the energy
transfer.
The higher the energy
transfer, the higher the
radiobiologic effect, which
can lead to lower total
doses.
Prostate Cancer
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The prostate gland is
just beneath the male
bladder.
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Cancer is common.
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The prostate gland can be felt with
a digital rectal exam, Cancer is
sometimes detected this way.
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67 year old male with metastatic prostate cancer.
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Iridium 192 is used for
high–dose rate treatment
of prostate cancer.
During the implantation,
hollow needles are
inserted transperineally.
The needles are then
connected to an
automated remotecontrolled loading
machine. The total
irradiation time is usually
only 5-10 minutes.
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Temporary seed placement is shown here.