Transcript Nuclear Medicine - El Camino College

Nuclear Medicine
Spring 2009
FINAL
NM Team
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Nuclear medicine MD
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Physicist
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Pharmacist
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Technologist
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Patient
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Principles of NM
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Uses radiopharmaceuticals for
diagnosis, therapy and medical
research
Small amounts of radioactive
material used
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Sometimes no more than that
received in CT or fluoroscopy
Studies physiology
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Rather than structural appearance
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Tracers
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Radioactive material that can be:
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Different tracers for different body parts
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Injected, ingested or inhaled
organ-, tissue-, or even cell-specific
They produce gamma-ray emissions from within
organ being studied
Gamma or scintillation camera transforms
emissions into images
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Provides information about function
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Modality Comparisons
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PET and SPECT for physiology
X-ray measures structure, size and position of
human anatomy
CT creates cross sectional images of anatomy
What do all of these modalities have in common?
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Atom Components & Isotopes
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Physical Principles of NM
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Radioactivity
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Radiation of energy
from the nucleus of
atom
Can be in the form of
alpha, beta particles or
gamma rays from the
nucleus
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Basic Nuclear Physics
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Nuclide
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Radionuclide
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Atom with a particular arrangement of protons and
neutrons in the nucleus
Unstable nucleus that transmutes by way of nuclear
decay (return to ground state)
Decay
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Is the atoms attempt to regain stability
By emission of alpha, beta and gamma radiation
Different for each type of radionuclide
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Half Life
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Physical time it takes for
a quantity of radionuclide
to decrease to ½ its
original activity
Radionuclides half life can
range from milliseconds
to years
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NM radionucldies range
from hours to days
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Nuclear Pharmacy
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Radiopharmaceutical
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Radionuclide
Pharmaceutical
Technetium -99
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Short ½ life of 6.04 hours
Low energy gamma photon
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Radiation Safety
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Radiopharmaceuticals
must be sterile
Prep area must have
isolated ventilation
Protective measures
when administering or
handling
Spills must be cleaned
immediately
Dosimetry devices
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Hands and badges
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Modern Day Gamma Camera
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Scintillate means: to emit light
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Ionizing radiation causes certain materials to glow
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Scintillation detector
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Detects radiation by observing the emission of light photons
emitted by the materials
PMT detect and convert light photons emitted from the
crystal into and electronic signal that amplifies the
original photon signal
It is then sent to be viewed
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Detectors
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Collimators
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Keep scattered rays from entering the
scintillation crystal
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Resolution and sensitivity
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Absorbs scattered gamma rays
Physical characteristics
Made of material with high atomic number
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Lead
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Crystals
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Sodium iodide Thallium
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Thick layer of crystals
High energies
 Decreased resolution
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Thin layer of crystals
Lower energies
 Increased resolution
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Attached to the back of
the crystals
Detect and convert light
photons into and
electronic signal that
amplifies the original
photon signal
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Photomultiplier
Tubes
About 80-100 in a gamma
camera
Light pipe
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Like a focusing device
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Put it all Together
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Computer
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Acquires and processes data received from
camera
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Post-processing
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In a time frame
Adjust contrast and density
Records
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Dosage
Quality control
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Types of Camera Systems
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Single detector
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Dual head
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Triple head
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Single Head Detector
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Dual Head Detector
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Triple Head Detector
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Imaging Methods
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Static
Whole- Body
Dynamic
SPECT
Co-registration
PET
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Static
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Single image of a particular structure
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Demonstrates radiopharmaceutical distribution
Ex: lung scans, spot bone scans images, thyroid
images
Obtained in various orientations, anterior,
posterior, and oblique
Low activity levels
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Generally 30 seconds to five minutes
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Whole Body
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Entire body or a large section of body
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Primarily used for
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Bone scans
Tumor scans
Abscess imaging
Clinical and research applications
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Dynamic
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Timed record of distribution of
radiopharmaceutical
Commonly used for
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Cardiac studies
Hepatobiliary studies
Gastric emptying studies
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Dynamic Renogram
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Dynamic Venogram
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SPECT
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Images similar to CT & MRI
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360 degree rotatator heads allows for:
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thin slices through a particular organ
Coronal, planar and 3D imaging
Ex: cardiac perfusion, brain, liver and
bone studies
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SPECT and CT combination
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Merges SPECT functional testing with CT
anatomic landmark images
Statistics show
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25-30% change of treatment options from
what would have been done with SPECT alone
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PET
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Resolution is 2-10 better than SPECT
Radiopharmaceuticals
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Minimal alteration in homeostasis
Very small amounts used
Co-registration being done with CT & MRI
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Almost all new machines are fused with a CT scanner
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