8.4.2 PET Scans

• What does the acronym PET stand for?

  Positron Emission Tomography
• PET scans provide information on the metabolic activity of tissues.
• What type of rays are detected in PET scans?

  Gamma rays
• A tracer is a radioactive substance used in PET scans.
• The tracer emits positrons that collide with nearby electrons.
• What type of image is created from the data collected in a PET scan?

  Metabolic activity image
• PET scans rely on the emission of gamma rays from a tracer.
• Steps in the PET scan process

  1️⃣ Introduce a tracer into the body

  2️⃣ The tracer accumulates in areas of high metabolic activity

  3️⃣ The tracer emits positrons that collide with electrons

  4️⃣ Gamma rays are produced and detected

  5️⃣ An image of metabolic activity is created
• What do radioactive tracers emit in PET scans?

  Positrons
• Match the tracer type with its use in PET scans:

  Fluorodeoxyglucose (FDG) ↔️ Tracks glucose metabolism

  Rubidium-82 ↔️ Evaluates heart blood flow

  Gallium-68 ↔️ Used for neuroendocrine tumors
• Patients must avoid eating for at least 6 hours before a PET scan to ensure stable glucose levels.
• Why is hydration important when preparing for a PET scan?

  Aids tracer distribution
• What type of medical imaging information do PET scans provide?

  Metabolic activity
• PET scans work by detecting pairs of gamma rays
• Describe the process of a PET scan in chronological order.

  1️⃣ Introduce a tracer into the body

  2️⃣ The tracer accumulates in areas of high metabolic activity

  3️⃣ The tracer emits positrons that collide with electrons

  4️⃣ Gamma rays are produced

  5️⃣ Detectors capture the gamma rays
• A glucose tracer is commonly used in PET scans to track metabolic activity.
• What particles are produced when positrons collide with electrons in a PET scan?

  Gamma rays
• PET scans utilize a tracer to visualize metabolic processes.
• Match the radioactive tracer with its specific use in PET scans:

  FDG ↔️ Brain glucose metabolism

  Rubidium-82 ↔️ Heart blood flow

  Gallium-68 ↔️ Neuroendocrine tumors
• FDG is commonly used in PET scans to diagnose Alzheimer's disease.
• What is the fasting requirement before a PET scan to ensure stable glucose levels?

  At least 6 hours
• Outline the steps involved in performing a PET scan.

  1️⃣ Inject a radioactive tracer

  2️⃣ The tracer emits positrons

  3️⃣ Positrons collide with electrons

  4️⃣ Gamma rays are detected

  5️⃣ An image is created
• What is the common tracer used in PET scans to track glucose metabolism?

  Fluorodeoxyglucose (FDG)
• Increased metabolic activity in a PET scan can suggest rapid cell growth or inflammation.
• Decreased metabolic activity in a PET scan may indicate cell damage or reduced function
• Increased metabolic activity in PET scans suggests rapid cell growth or inflammation
• Decreased metabolic activity in PET scans indicates cell damage or reduced function
• What does increased glucose uptake in a specific brain area indicate?

  Brain tumor
• What does decreased glucose uptake in the frontal cortex suggest?

  Alzheimer's disease
• PET scans detect pairs of gamma rays emitted by a tracer
• What type of tracer is used in brain imaging with PET scans?

  Glucose tracer
• Steps in how PET scans work

  1️⃣ A tracer is injected and accumulates in areas of high metabolic activity.

  2️⃣ The tracer emits positrons that meet electrons, producing pairs of gamma rays.

  3️⃣ Detectors surrounding the patient capture these gamma rays.

  4️⃣ A computer uses this data to generate an image showing metabolic activity.
• Positrons emitted by the tracer meet electrons to produce gamma rays.
• In Alzheimer's disease, a PET scan reveals increased glucose uptake in the brain.

  False
• Radioactive tracers in PET scans emit positrons that collide with electrons
• What does the Fluorodeoxyglucose (FDG) tracer track in brain imaging?

  Glucose metabolism
• Which tracer is used to evaluate heart blood flow in PET scans?

  Rubidium-82
• Patients preparing for a PET scan must avoid eating for at least 6 hours
• Drinking plenty of water before a PET scan aids tracer circulation.
• What should patients inform their medical team about before a PET scan?

  All medications