Bookmarks
KEY FACTS
Positron Emission Tomography
2D and 3D Acquisition Modes
Attenuation Correction
TERMINOLOGY
Definitions
- Positron emission tomography (PET)
- Imaging of 511 keV gamma photons produced after annihilation
- Ring of detectors surrounds patient and detects coincident gamma photons emitted, creating 3D image
- Positrons (beta +)
- Radioactive decay of positron emitters
- Same mass as electrons but positively charged
- Travel short distance before combining with free electrons and annihilating; annihilation produces 2 511 keV gamma ray photons
- Positron emitter: Radionuclides that emit positrons (beta +)
- Positron inside nucleus transforms into neutron (which remains in nucleus) and positron and neutrino (both of which are ejected from atom)
- Secondary probability for electron capture: Electron combines with proton from nucleus to become neutron plus neutrino
- e.g., F-18 has 97% probability of positron emission and 3% probability of electron capture
- Secondary probability for electron capture: Electron combines with proton from nucleus to become neutron plus neutrino
- ρ⁺ (proton) → η (neutron) + β⁺ (positron) + ν (neutrino) + energy
- Total # of protons (atomic number) decreased by 1
- Total # of neutrons increased by 1
- Mass # unchanged (= # of protons + # of neutrons)
- Positron inside nucleus transforms into neutron (which remains in nucleus) and positron and neutrino (both of which are ejected from atom)
- Annihilation
- When positron combines with electron
- Mass of positron and electron converted to energy in form of 2 511 keV gamma photons given off in opposite directions (~ 180° apart)
- 511 keV gamma photons part of electromagnetic family (move at speed of light, have no mass, and have no charge)
- Positron emission tomography (PET)
IMAGING ANATOMY
PET Radionuclides
Flow of Data and Processing
PET Detector Array Design
PET Image Quality
Imaging Features
2D Direct Imaging
2D Cross-Plane Imaging
2D High-Sensitivity Imaging
3D Imaging
PET/CT
PET/MR
Attenuation Correction
Standard Uptake Value
Quality Control
Artifacts
Selected References
- Conti M et al: Physics of pure and non-pure positron emitters for PET: a review and a discussion. EJNMMI Phys. 3(1):8, 2016
- Ziessman HA et al. Nuclear Medicine: The Requisites, 4th Edition (Requisites in Radiology). Saunders, 2013
- Granov A et al. Positron Emission Tomography. Springer, 2013
- Chandra R. Nuclear Medicine Physics: The Basics, 7th Edition. Lippincott, Williams and Wilkins, 2012
- Bushberg JT et al. The Essential Physics of Medical Imaging, 3rd Edition. Lippincott, Williams and Wilkins, 2011
- Saha GB. Basics of PET Imaging: Physics, Chemistry, and Regulations. Springer, 2004
- Christian PE et al. Nuclear Medicine and PET: Technology and Techniques, 5th Edition. Mosby, 2004
- Valk PE et al. Positron Emission Tomography: Basic Science and Clinical Practice. Springer, 2002
- International Atomic Energy Agency. Cyclotron Produced Radionuclides: Physical Characteristics and Production Methods. http://www-pub.iaea.org/MTCD/publications/PDF/trs468_web.pdf. Accessed March 1, 2020
Related Anatomy
Loading...
Related Differential Diagnoses
Loading...
References
Tables
Tables
KEY FACTS
Positron Emission Tomography
2D and 3D Acquisition Modes
Attenuation Correction
TERMINOLOGY
Definitions
- Positron emission tomography (PET)
- Imaging of 511 keV gamma photons produced after annihilation
- Ring of detectors surrounds patient and detects coincident gamma photons emitted, creating 3D image
- Positrons (beta +)
- Radioactive decay of positron emitters
- Same mass as electrons but positively charged
- Travel short distance before combining with free electrons and annihilating; annihilation produces 2 511 keV gamma ray photons
- Positron emitter: Radionuclides that emit positrons (beta +)
- Positron inside nucleus transforms into neutron (which remains in nucleus) and positron and neutrino (both of which are ejected from atom)
- Secondary probability for electron capture: Electron combines with proton from nucleus to become neutron plus neutrino
- e.g., F-18 has 97% probability of positron emission and 3% probability of electron capture
- Secondary probability for electron capture: Electron combines with proton from nucleus to become neutron plus neutrino
- ρ⁺ (proton) → η (neutron) + β⁺ (positron) + ν (neutrino) + energy
- Total # of protons (atomic number) decreased by 1
- Total # of neutrons increased by 1
- Mass # unchanged (= # of protons + # of neutrons)
- Positron inside nucleus transforms into neutron (which remains in nucleus) and positron and neutrino (both of which are ejected from atom)
- Annihilation
- When positron combines with electron
- Mass of positron and electron converted to energy in form of 2 511 keV gamma photons given off in opposite directions (~ 180° apart)
- 511 keV gamma photons part of electromagnetic family (move at speed of light, have no mass, and have no charge)
- Positron emission tomography (PET)
IMAGING ANATOMY
PET Radionuclides
Flow of Data and Processing
PET Detector Array Design
PET Image Quality
Imaging Features
2D Direct Imaging
2D Cross-Plane Imaging
2D High-Sensitivity Imaging
3D Imaging
PET/CT
PET/MR
Attenuation Correction
Standard Uptake Value
Quality Control
Artifacts
Selected References
- Conti M et al: Physics of pure and non-pure positron emitters for PET: a review and a discussion. EJNMMI Phys. 3(1):8, 2016
- Ziessman HA et al. Nuclear Medicine: The Requisites, 4th Edition (Requisites in Radiology). Saunders, 2013
- Granov A et al. Positron Emission Tomography. Springer, 2013
- Chandra R. Nuclear Medicine Physics: The Basics, 7th Edition. Lippincott, Williams and Wilkins, 2012
- Bushberg JT et al. The Essential Physics of Medical Imaging, 3rd Edition. Lippincott, Williams and Wilkins, 2011
- Saha GB. Basics of PET Imaging: Physics, Chemistry, and Regulations. Springer, 2004
- Christian PE et al. Nuclear Medicine and PET: Technology and Techniques, 5th Edition. Mosby, 2004
- Valk PE et al. Positron Emission Tomography: Basic Science and Clinical Practice. Springer, 2002
- International Atomic Energy Agency. Cyclotron Produced Radionuclides: Physical Characteristics and Production Methods. http://www-pub.iaea.org/MTCD/publications/PDF/trs468_web.pdf. Accessed March 1, 2020
