Gamma Camera Parallel Hole Collimators
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Questions and Answers

What is a major limitation of the gamma camera?

  • The absorption of gamma photons by the collimator's material (correct)
  • The camera's limited field of view
  • The camera's ability to detect gamma photons
  • The inability to produce high-resolution images

    • What is the primary function of a collimator in gamma ray detection?

  • To filter out unwanted gamma photons (correct)
  • To reduce the field of view of the gamma camera
  • To map gamma rays onto the scintillator
  • To increase the sensitivity of the gamma camera

    • What is the benefit of using a hexagonal structured hole arrangement in parallel hole collimators?

  • It increases the sensitivity of the gamma camera
  • It filters out unwanted gamma photons
  • It maximises the exposed area of the gamma camera detector (correct)
  • It reduces the field of view of the gamma camera

    • What determines the appropriate type of collimator for gamma ray detection?

    <p>The desired level of sensitivity and spatial resolution</p> Signup and view all the answers

    What is the purpose of the scintillator in gamma imaging?

    <p>To map gamma rays onto the image</p> Signup and view all the answers

    What is a characteristic of parallel hole collimators?

    <p>They have a hexagonal structured hole arrangement</p> Signup and view all the answers

    What is a common material used in the construction of parallel hole collimators?

    <p>Lead</p> Signup and view all the answers

    What is the purpose of doping NaI crystals with thallium atoms?

    <p>To improve the scintillator's response to gamma photons</p> Signup and view all the answers

    What is the result of the interaction between the incident photons and the scintillator's material?

    <p>The release of energetic electrons</p> Signup and view all the answers

    What is the fate of the electrons in an excited state?

    <p>They return to their stable state by releasing energy as optical photons</p> Signup and view all the answers

    What is the relationship between crystal thickness and gamma photon absorption?

    <p>Thicker crystals absorb most incident gamma photons</p> Signup and view all the answers

    What is a drawback of using thick crystals in scintillators?

    <p>Reduced spatial resolution</p> Signup and view all the answers

    What is the primary factor influencing the scintillation process?

    <p>The crystal design</p> Signup and view all the answers

    What is the ultimate outcome of the electrons released during the scintillation process?

    <p>They release energy as optical photons</p> Signup and view all the answers

    What is the primary function of the focusing electrode in a photomultiplier tube?

    <p>To direct the photoelectrons towards the first dynode</p> Signup and view all the answers

    What is the ultimate purpose of the cascade procedure in a photomultiplier tube?

    <p>To collect all the electrons at the anode</p> Signup and view all the answers

    What is the result of the collision between the primary electrons and the first dynode surface?

    <p>The liberation of more electrons</p> Signup and view all the answers

    What is the purpose of minimizing scattered gamma photons in a gamma camera?

    <p>To enhance the produced gamma image quality</p> Signup and view all the answers

    What is the nature of the gamma image produced by a conventional gamma camera?

    <p>A true mapping of the spatial locations of the detected gamma photons</p> Signup and view all the answers

    What is the role of the dynodes in a photomultiplier tube?

    <p>To amplify the electrons through a series of stages</p> Signup and view all the answers

    What is the final destination of the electrons in a photomultiplier tube?

    <p>The anode</p> Signup and view all the answers

    What is the typical thickness range of parallel hole collimators manufactured for traditional gamma cameras?

    <p>25-80 mm</p> Signup and view all the answers

    What is a characteristic of the structure of parallel bore arrays in parallel hole collimators?

    <p>Symmetrical with identical holes</p> Signup and view all the answers

    What is an advantage of parallel hole collimators compared to pinhole collimators?

    <p>Superior level of sensitivity</p> Signup and view all the answers

    What is a limitation of collimators in gamma imaging systems?

    <p>Most off-axis gamma photons are absorbed</p> Signup and view all the answers

    Why do parallel hole collimators allow several incidence angles?

    <p>Because the hole diameter is not infinitesimally small</p> Signup and view all the answers

    What factor determines the septal thickness in parallel-hole collimators?

    <p>Energy of the gamma photons</p> Signup and view all the answers

    What is the effect of increasing the hole diameter in parallel hole collimators?

    <p>Wider range of acceptance angles</p> Signup and view all the answers

    What is the primary reason for minimizing scattered gamma photon penetration in the collimator body?

    <p>To avoid the projection of inaccurate data on the gamma image</p> Signup and view all the answers

    What is the main difference between parallel hole collimators and non-parallel hole collimators?

    <p>Field of view</p> Signup and view all the answers

    Which type of collimator is used for scanning small targeted areas, such as brain or cardiac procedures?

    <p>Converging collimator</p> Signup and view all the answers

    What is the primary purpose of using a diverging collimator?

    <p>To collect gamma photons from a large region of interest</p> Signup and view all the answers

    What is the typical material used to make a pinhole collimator?

    <p>Tungsten, lead, or platinum</p> Signup and view all the answers

    What is the diameter range of the aperture in a pinhole collimator?

    <p>2-6 mm</p> Signup and view all the answers

    What type of collimator is suitable for nuclear medicine clinics with small organ imaging procedures?

    <p>Pinhole collimator</p> Signup and view all the answers

    What is the advantage of using a pinhole collimator in examining bone joints, paediatric scans, and skeletal extremities?

    <p>Enhanced effectiveness</p> Signup and view all the answers

    What is the primary difference between parallel hole collimators and pinhole collimators?

    <p>Structural shape</p> Signup and view all the answers

    Why are non-parallel hole collimators used in nuclear medicine?

    <p>To satisfy the needs of specific scanning procedures</p> Signup and view all the answers

    What is the primary reason for minimizing scattered gamma photon penetration in the collimator body?

    <p>To avoid the projection of inaccurate data on the gamma image</p> Signup and view all the answers

    What is the main difference between parallel hole collimators and non-parallel hole collimators?

    <p>The hole structure, which affects the field of view</p> Signup and view all the answers

    What is the purpose of adjusting the septal thickness in parallel-hole collimators?

    <p>To minimize scattered gamma photon penetration</p> Signup and view all the answers

    Which type of collimator provides a larger field of view compared to parallel-hole collimators?

    <p>Diverging collimator</p> Signup and view all the answers

    What is the primary advantage of using pinhole collimators in nuclear medicine clinics?

    <p>They are more suitable for small organ imaging procedures</p> Signup and view all the answers

    What is the primary advantage of using parallel hole collimators in gamma imaging?

    <p>Improved sensitivity due to maximized exposed area of the gamma camera detector</p> Signup and view all the answers

    What is the primary factor that determines the appropriate septal thickness in parallel-hole collimators?

    <p>Desired level of sensitivity and spatial resolution</p> Signup and view all the answers

    What is the main difference between parallel hole collimators and non-parallel hole collimators?

    <p>Hole structure and arrangement</p> Signup and view all the answers

    What is the effect of increasing the hole diameter in parallel hole collimators?

    <p>Improved sensitivity due to increased exposed area</p> Signup and view all the answers

    What is the primary reason for minimizing scattered gamma photon penetration in the collimator body?

    <p>To reduce scattered gamma photon penetration</p> Signup and view all the answers

    What is the main difference between parallel hole collimators and non-parallel hole collimators?

    <p>Hole diameter and pattern of arrangement</p> Signup and view all the answers

    What determines the septal thickness in parallel-hole collimators?

    <p>The hole diameter and pattern of arrangement</p> Signup and view all the answers

    What is the primary purpose of the multi-hole collimator in a gamma camera?

    <p>To delineate the image from the patient</p> Signup and view all the answers

    What is the effect of increasing the hole diameter in parallel hole collimators?

    <p>Decreased sensitivity and resolution</p> Signup and view all the answers

    What is the primary reason why parallel hole collimators are limited in their field of view?

    <p>Most of the off-axis gamma photons are absorbed by the collimator body.</p> Signup and view all the answers

    What is the primary reason for minimizing scattered gamma photon penetration in the collimator body?

    <p>To reduce the noise and artifacts in the image</p> Signup and view all the answers

    What determines the septal thickness in parallel-hole collimators?

    <p>The diameter of the collimator holes</p> Signup and view all the answers

    What is the primary factor that determines the septal thickness in parallel-hole collimators?

    <p>The energy of the gamma photons.</p> Signup and view all the answers

    What is the typical field of view in a pinhole collimator?

    <p>Small, covering specific targeted structures</p> Signup and view all the answers

    What is the effect of increasing the hole diameter in parallel hole collimators?

    <p>Increased gamma photon penetration</p> Signup and view all the answers

    What is the result of increasing the hole diameter in parallel hole collimators?

    <p>The collimator allows a wider range of acceptance angles.</p> Signup and view all the answers

    What is a characteristic of large field of view (LFOV) gamma cameras?

    <p>They are assembled with diversified hardware and connections</p> Signup and view all the answers

    Why do parallel hole collimators provide a superior level of sensitivity compared to pinhole collimators?

    <p>Parallel hole collimators allow more gamma photons to pass through.</p> Signup and view all the answers

    What is the primary reason for using parallel hole collimators in gamma imaging systems?

    <p>To allow for several incidence angles</p> Signup and view all the answers

    What is the primary advantage of using parallel hole collimators over non-parallel hole collimators?

    <p>Parallel hole collimators provide a superior level of sensitivity.</p> Signup and view all the answers

    What is the purpose of medium-energy collimators?

    <p>For use up to 400 keV with thicker septa</p> Signup and view all the answers

    What is a limitation of conventional planar gamma imaging?

    <p>Lack of depth information</p> Signup and view all the answers

    What determines the sensitivity of a parallel hole collimator?

    <p>Number of holes</p> Signup and view all the answers

    What is the purpose of reducing scattered gamma photon penetration in the collimator body?

    <p>To reduce sensitivity</p> Signup and view all the answers

    What is the advantage of using a non-parallel hole collimator compared to a parallel hole collimator?

    <p>Larger field of view</p> Signup and view all the answers

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

    <p>It reduces the image acquisition time or improves the sensitivity</p> Signup and view all the answers

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

    <p>It minimizes the gap between the collimator and the patient, improving the resolution</p> Signup and view all the answers

    What is the advantage of using three or four gamma cameras equally spaced around the rotating gantry in SPECT?

    <p>It improves the sensitivity of the image</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 a major use of SPECT?

    <p>Both A and B</p> Signup and view all the answers

    What is the primary purpose of minimizing scattered gamma photon penetration in parallel-hole collimators?

    <p>To improve image resolution</p> Signup and view all the answers

    What determines the appropriate septal thickness in parallel-hole collimators?

    <p>The energy of the gamma photons</p> Signup and view all the answers

    What is the advantage of using non-parallel hole collimators in some applications?

    <p>They are more suitable for small organ imaging</p> Signup and view all the answers

    What is the effect of increasing the hole diameter in parallel hole collimators?

    <p>It increases the sensitivity of the detector</p> Signup and view all the answers

    What is the primary difference between parallel hole collimators and non-parallel hole collimators?

    <p>The field of view they provide</p> Signup and view all the answers

    What is the purpose of adjusting the septal thickness in parallel-hole collimators?

    <p>To minimize scattered gamma photon penetration</p> Signup and view all the answers

    What is the advantage of using parallel hole collimators in gamma imaging?

    <p>They increase the sensitivity of the detector</p> Signup and view all the answers

    What is the primary factor that determines the appropriate septal thickness in parallel-hole collimators?

    <p>The energy of the gamma photons</p> Signup and view all the answers

    What is the primary advantage of using pinhole collimators in nuclear medicine clinics?

    <p>They are more suitable for small organ imaging</p> Signup and view all the answers

    What is the primary reason for using non-parallel hole collimators in some applications?

    <p>They are more suitable for small organ imaging</p> Signup and view all the answers

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