Nuclear Medicine Overview by sammyc2007

VIEWS: 293 PAGES: 65

									   Nuclear Medicine

Imaging and the treatment of
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
   What are the             Gamma radiation is
    properties of gamma       very high-energy
    radiation?                ionizing radiation.
                             Gamma photons have
                              no mass and no
                              electrical charge--they
                              are pure
            Gamma Radiation

   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

   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

   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

   Uses of Cesium-137:
   cancer treatment
   Uses of Cobalt-60:
   sterilize medical equipment in hospitals
   treat cancer
            Gamma Radiation

   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

   1. Competitive Binding Assays
   2. Time Dependent Measurements
   3. Radio Nucleotide Imaging
       Gamma Camera – scintillation camera
   4. Tomography
       SPECT imaging
       PET imaging
    1. Competitive Binding Assays

   No radioactive substance is given to the
   Blood from a patient is mixed with a
    radioactive substance in the laboratory
       Radioimmunoassay
           Thyroid Hormone and Iron Binding Sites most
1. Competitive Binding Assays
2. Time Dependent Measurements

   Radioactive Tracers are to the patient

   Allows the volume of a compartment to be
Intravenous Pyelogram
                  An Intravenous
                   Pyelogram (IVP)
                   is an x-ray
                   examination of
                   the kidneys,
                   ureters, and
                   urinary bladder.
Intravenous Pyelogram

   This is a test
    done to
    obstruction of
    the bile ducts
    (for example,
    by a gallstone
    or a tumor),
    disease of the
    and bile leaks.
Cardiac Angiography
             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
   The arrow indicates a
    blockage in the right
    coronary artery.
Cerebral Angiogram
   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
   Cerebral angiogram
    taken after
    angioplasty: The
    narrowing is less
    severe and the
    branches beyond the
    narrowing fill better
3. Radionucleotide Imaging
                Image is generated
                 using radioactive
                 decay from an organ
                Usually a function of
                Provide functional
     3. Radionucleotide Imaging
   Single detectors are
    used for thyroid
3. Radionucleotide Imaging
                  Scintillation Camera
                  Shows two
                   dimensional data
                  Studies physiologic
   Ventilation-Perfusion
    Scan of a lung looking
    for a blood clot.
   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
   A small amount of
    injected radioactive
    matter (tracer) and a
    camera to form an
                                Bone scan looking for
                                metastatic bone cancer.
   Looking for fibrous
    dysplasia that is a
    congenital, non-
    hereditary skeletal
   Patients are often
    asymptomatic. Others
    experience pain,
    pathologic fractures
    and bone deformity
   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 non-
    healing ulcer of the left
    first toe.
   This Indium White
    Blood Cell Scan
    demonstrates areas of
    infection in the
    abdomen after
    surgery for colon
               4. Tomography

   The fourth class of imaging is the
    tomographic reconstruction of body slices.
       Single-photon emission computer tomography
        - SPECT scan
       Position Emission Tomography – PET scan
                SPECT Imaging
   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

   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
    Blood flow to the brain is
    represented on a color
    scale, dark areas have no
    flow and bright yellow
    areas have good blood
   The dark "butterfly-
    shaped" 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.
   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
PET Scanner
                              Image of heart which has
   Normal PET scan of a       had a mycardial infarction.
    heart.                     The arrow points to "dead"
                               myocardial tissue.
                               Therefore, the patient will
                               not benefit from heart
                               surgery, but may have other
                               forms of treatment
                                     PET image of same patient
   PET image showing malignant       with enlarged left axillary
    breast mass that was not          lymph nodes (indicated by
    revealed by conventional          arrows), which through biopsy
    imaging techniques such as        were found to be metastatic.
    CT, MRI, and mammogram            The whole body scan reveals a
                                      mass in the left breast
                                      (indicated by arrow), that was
                                      malignant and subsequently
   Normal Brain      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 "seizure-
   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

   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
   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
   Zapping Cancer Proton Beam
    Therapy Proves Effective in Targeting
    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.
Proton Beam Radiotherapy
               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 low-
                energy eye-plaque
                radiation therapy, It is
                easier to treat tumors
                that are surrounding the
                optic nerve with protons.
          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
          The term "brachy" is
           Greek for short distance.
   Brachytherapy is not new. Throughout this
    century, several types and routes of
    implantation of radioactive seeds have been
    used to treat cancer.

   Radioactive Iodine seeds were widely used
    during the 1970s and 1980s.
   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.
   Currently, temporary
    implants consist
    primarily of 192Ir and
   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
   The higher the energy
    transfer, the higher the
    radiobiologic effect, which
    can lead to lower total
              Prostate Cancer

   The prostate gland is      Cancer is common.
    just beneath the male
   The prostate gland can be felt with
    a digital rectal exam, Cancer is
    sometimes detected this way.
   67 year old male with metastatic prostate cancer.
   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 remote-
    controlled loading
    machine. The total
    irradiation time is usually
    only 5-10 minutes.
   Temporary seed placement is shown here.

To top