SPECT Imaging Techniques
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Questions and Answers

What is the main limitation of conventional planar gamma imaging?

  • Loss of depth information and reduced contrast (correct)
  • High cost of equipment
  • Low sensitivity
  • Long exposure times

    • What is the purpose of using a parallel hole collimator in SPECT?

  • To improve the resolution of the image (correct)
  • To reduce the number of counts acquired
  • To rotate the camera slowly in a circular orbit
  • To increase the scanning time

    • How many views are taken in a SPECT scan?

  • 60 views (correct)
  • 90 views
  • 30 views
  • 120 views

    • What is the total scanning time required for a SPECT scan?

    <p>30 minutes</p> Signup and view all the answers

    How many counts are acquired in a SPECT scan?

    <p>3 million counts</p> Signup and view all the answers

    What are the two methods of emission tomography?

    <p>SPECT and PET</p> Signup and view all the answers

    What is the benefit of using a dual- or triple-headed camera in SPECT?

    <p>Halved image acquisition time or improved sensitivity</p> Signup and view all the answers

    What is the purpose of using an elliptical orbit in SPECT?

    <p>To reduce the gap between the collimator and the patient</p> Signup and view all the answers

    What is a useful rotation option in cardiac tomography in SPECT?

    <p>180°</p> Signup and view all the answers

    What is a major use of SPECT?

    <p>Thallium studies of myocardial infarctions and ischaemia</p> Signup and view all the answers

    How can SPECT studies be presented?

    <p>Either as a series of slices or as a three-dimensional display</p> Signup and view all the answers

    What is the effect of persistence of vision in SPECT image display?

    <p>Reduces image noise</p> Signup and view all the answers

    What is the purpose of testing for radionuclide purity in radiopharmaceuticals?

    <p>To prevent unnecessary dose to the patient</p> Signup and view all the answers

    How is the patient administered a radiopharmaceutical in planar imaging?

    <p>Intravenously, through an injection</p> Signup and view all the answers

    What is the ideal function of a radiopharmaceutical in planar imaging?

    <p>To concentrate in the organ or tissues of interest</p> Signup and view all the answers

    What is the purpose of testing for radiochemical purity in radiopharmaceuticals?

    <p>To detect free pertechnetate in a labelled compound</p> Signup and view all the answers

    What is the purpose of testing for chemical purity in radiopharmaceuticals?

    <p>To detect the presence of alumina</p> Signup and view all the answers

    What is the purpose of the dose calibrator in radiopharmaceuticals?

    <p>To measure the activity of the radiopharmaceutical</p> Signup and view all the answers

    What percentage of nuclides in the world are stable?

    <p>Nearly 100%</p> Signup and view all the answers

    What is the main reason for innovation in nuclear medicine diagnostic imaging over the last century?

    <p>Development of new equipment and techniques</p> Signup and view all the answers

    What is the significance of Röntgen’s discovery of X-rays?

    <p>It started the innovation in diagnostic imaging</p> Signup and view all the answers

    What is the requirement for practicing nuclear medicine safely?

    <p>Clear understanding of the behavior and principles of radiation sources and radiation detection</p> Signup and view all the answers

    What is unique about the nucleus of ordinary hydrogen?

    <p>It has a single proton</p> Signup and view all the answers

    What is the general trend in the composition of stable lighter nuclei?

    <p>They have nearly equal numbers of protons and neutrons</p> Signup and view all the answers

    What is the result of forcing an additional neutron into a stable nucleus?

    <p>A neutron excess</p> Signup and view all the answers

    What is the result of a positive beta particle coming to the end of its range?

    <p>It combines with a negative electron</p> Signup and view all the answers

    What is the purpose of a cyclotron in producing radionuclides?

    <p>To accelerate positively charged ions</p> Signup and view all the answers

    What is the energy of each photon emitted during the annihilation of a positive and negative electron?

    <p>511 keV</p> Signup and view all the answers

    What is the characteristic of the half-lives of radionuclides produced in a cyclotron?

    <p>Short-lived, ranging from less than a minute to a couple of hours</p> Signup and view all the answers

    What type of radiation is emitted when an electron from an outer shell fills a created vacancy in the K-shell?

    <p>X-ray radiation</p> Signup and view all the answers

    Why are medical minicyclotrons designed to be located near hospital sites?

    <p>To enable the use of short-lived radionuclides in medical imaging</p> Signup and view all the answers

    What is the result of forcing an additional proton into a stable nucleus?

    <p>An increase in atomic number</p> Signup and view all the answers

    What is the characteristic of gamma rays emitted during radioactive decay?

    <p>A line spectrum of specific energies</p> Signup and view all the answers

    What is the process by which a nuclide with a neutron deficit decays?

    <p>K-electron capture</p> Signup and view all the answers

    What is the total number of known radionuclides?

    <p>More than 2700</p> Signup and view all the answers

    What is the result of the combination of a positive and negative electron?

    <p>The neutralization of opposite charges</p> Signup and view all the answers

    What is the decay process in which a radionuclide with a neutron excess loses energy and becomes stable?

    <p>Beta minus decay</p> Signup and view all the answers

    What is the name of the radionuclide that is produced from the decay of Molybdenum-99?

    <p>Technetium-99m</p> Signup and view all the answers

    What is the energy of the gamma ray emitted during the decay of Technetium-99m to Technetium-99?

    <p>140 keV</p> Signup and view all the answers

    What is the change in the atomic number of Iodine-131 during its decay to Xenon-131?

    <p>Increases by one</p> Signup and view all the answers

    What is the process by which a radionuclide in an excited state returns to its ground state with the emission of a gamma ray?

    <p>Isomeric transition</p> Signup and view all the answers

    What is the name of the radionuclide that is produced from the decay of Germanium-68?

    <p>Gallium-68</p> Signup and view all the answers

    What is the result of adding a neutron to the nucleus of Molybdenum-98?

    <p>The atomic number of the nucleus remains unchanged, but its mass increases by one</p> Signup and view all the answers

    What happens when an additional proton is forced into a stable nucleus in a cyclotron?

    <p>A neutron is knocked out of the nucleus, resulting in a neutron deficit</p> Signup and view all the answers

    What is a characteristic of radionuclides produced in a cyclotron?

    <p>They have short half-lives, ranging from less than a minute to a couple of hours</p> Signup and view all the answers

    What is a medical application of radionuclides produced in a cyclotron?

    <p>They are used in medical imaging, such as in the production of fluorine-18</p> Signup and view all the answers

    What is a method of producing radionuclides?

    <p>Extracting radioactive fission products from spent fuel rods of nuclear reactors</p> Signup and view all the answers

    What is a characteristic of radionuclides obtained from generator systems?

    <p>They are daughter products obtained from a longer-lived radioactive parent</p> Signup and view all the answers

    Study Notes

    Image Acquisition and SPECT

    • Image acquisition time can be halved or sensitivity improved by using a dual- or triple-headed camera.
    • The camera must move on a sufficiently large circular orbit to avoid the patient's shoulders.
    • An elliptical orbit can be used to minimize the gap between the collimator and the patient, improving resolution.
    • A 180° rotation is a useful option, especially in cardiac tomography.

    SPECT Studies and Display

    • SPECT studies can be presented as a series of slices or as a 3D display.
    • The 3D display is particularly effective when rotated continuously on the computer screen, reducing the effect of image noise.

    Applications of SPECT

    • Thallium studies of myocardial infarctions and ischaemia are major uses of SPECT.
    • SPECT can be used in dynamic imaging where short exposure times are necessary, accepting poorer resolution.

    Collimators

    • Medium-energy collimators have thicker septa (1.4 mm) and fewer holes, resulting in lower sensitivity.
    • They are used up to 400 keV, e.g., with 111In, 67Ga, and 131I.

    Tomography with Radionuclides

    • Conventional planar gamma imaging produces a 2D projection of a 3D distribution of a radiopharmaceutical.
    • The images of organs are superimposed, losing depth information and reducing contrast.
    • Emission tomography addresses these deficiencies.

    Types of Emission Tomography

    • There are two methods of emission tomography: Single-Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET).

    SPECT Process

    • In its simple form, a gamma camera with a parallel hole collimator rotates slowly in a circular orbit around the patient.
    • Every 6°, the camera halts for 20-30s and acquires a view of the patient.
    • 60 views are taken from different directions, each with fewer counts than in conventional static imaging.

    SPECT Scanning

    • Approximately 3 million counts are acquired in an overall scanning time of around 30 minutes.
    • This technology reduces the radiation exposure of the staff.

    Radiopharmaceuticals and Quality Control

    • Quality control includes testing for:
      • Radionuclide purity
      • Radiochemical purity
      • Chemical purity
      • Response of the radionuclide calibrator

    Radiation and Decay

    • Radionuclides with a neutron excess may lose energy and become stable by a neutron changing into a proton plus an electron.
    • The electron is ejected from the nucleus with high energy and is referred to as a negative beta particle.
    • Isomeric transition can occur in some radionuclides, where the gamma ray is not emitted until an appreciable time after the emission of the beta particle.

    Introduction to Nuclear Medicine

    • The technologies used in nuclear medicine for diagnostic imaging have improved over the last century.
    • Each decade has brought innovation in the form of new equipment, techniques, radiopharmaceuticals, advances in radionuclide production, and better patient care.
    • All such technologies have been developed and can only be practiced safely with a clear understanding of the behavior and principles of radiation sources and radiation detection.

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    Related Documents

    Nuclear Medicine Physics Module Lecture Notes PDF

    Description

    Learn about the techniques used in Single-Photon Emission Computed Tomography (SPECT) imaging, including camera orbit and rotation options to improve image acquisition and resolution.

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