Lesson-2-Nuclear-Medicine-Prelim
Page 1: Nuclear Medicine
Nuclear Medicine L2
Instructor: Chris John A. Doria, R.R.T.
Page 2: Properties of Radiation
Main Categories of Radiation
Non-ionizing Radiation: Cannot ionize matter; examples include near ultraviolet radiation, visible light, infrared photons, microwaves, and radio waves.
Ionizing Radiation: Can ionize matter directly or indirectly; includes X-rays, gamma rays, energetic neutrons, protons, and heavier particles.
Page 3: Interaction with Matter
Radiation can be categorized into ionizing and non-ionizing.
Ionizing radiation poses a greater risk to living organisms and can cause DNA damage.
Non-ionizing radiation is typically harmful only when energy deposition causes a thermal effect.
Page 4: Non-Ionizing Radiation
Defined as radiation with energies below a threshold (10 or 33 electronvolts; eV).
Natural Sources: Sunlight primarily consists of non-ionizing radiation.
Page 5: Types of Non-Ionizing Radiation
Visible Light: Electromagnetic radiation visible to the human eye.
Infrared Radiation: Invisible but sensed as heat.
Microwave Radiation: Used in cooking.
Radiowave Radiation: Comes in electromagnetic waves of radiofrequency.
Page 6: Continued Non-Ionizing Radiation
Ultraviolet Radiation: Invisible and harmful in excess.
Cosmic Radiation: Harmful to air crews and astronauts; mostly filtered by Earth's atmosphere.
Blackbody Radiation: Radiation from an ideal radiator at any temperature.
Page 7: Ionizing Radiation
Ionizing radiation transfers enough energy to displace electrons, creating ions that can harm cells.
Uses: Smoke detectors, cancer treatment, and sterilization of medical equipment.
Page 8: Alpha Radiation
Characteristics:
Heavy and short-range particles (helium nucleus), cannot penetrate human skin.
Harmful if ingested or inhaled.
Detectable with thin-window Geiger-Mueller probes.
Page 9: Beta Radiation
Characteristics:
Light particles (ejected electrons) that can travel several feet in air and penetrate skin.
Can be harmful internally and is detectable with thin-window G-M probes.
Clothing offers some protection.
Page 10: Radiation Penetration Comparison
Penetrating Power:
Alpha particles: Low penetration (stopped by paper).
Beta particles: Moderate penetration (stopped by body tissue).
X-rays and gamma rays: High penetration (stopped by concrete or lead).
Page 11: Gamma and X Radiation
Highly penetrating electromagnetic radiation capable of traveling many feet in air and inches in tissue.
Requires dense material for shielding (e.g., concrete, lead).
Used in medical applications, including cancer treatment and imaging.
Page 12: Continued Gamma and X Radiation
Detectable through survey meters.
Gamma rays can accompany alpha and beta emissions during radioactive decay.
Page 13: Neutron Particles
Characteristics:
High-speed nuclear particles that can induce radioactivity.
Travel longer distances, requiring substantial shielding.
Hazardous primarily during nuclear reactions or blasts.
Page 14: Nuclear Medicine L3
Continuing with Chris John A. Doria, R.R.T.
Page 15: What is Radioactivity?
Spontaneous emission of radiation by unstable atomic nuclei.
Different types of emissions lead to changes in the nucleus.
Page 16: History of Radioactivity
Discovered by Henri Becquerel on March 1, 1896, through accidental observation.
Connected his studies of uranium with x-rays.
Page 17: Continued History of Radioactivity
Becquerel experimented with uranium salts, discovering they emitted radiation without sunlight.
Page 18: Further Development of Radioactivity Study
Becquerel showed that uranium salts emitted radiation independently.
Page 19: Contributions by Marie and Pierre Curie
Curies uncovered more radioactive elements and defined "radioactivity."
Page 20: Measuring Radioactivity
Radioactivity is measured by counting decays.
Units: Curie (Ci) = 37 billion decays/second; Becquerel (Bq) = 1 decay/second.
Page 21: Radioactive Half-Life
Defined as the time for half of atoms in a sample to decay; varies greatly across elements.
Page 22: Radioactive Decay Chains
Stability can occur after one or several emissions, with each state having unique characteristics.
Page 23: Sources of Natural Radioactivity
Various isotopes emit different radiation types during decay.
Page 24: Artificial Radioactivity
Induced through human action, such as neutron activation; involved in medical therapies.
Page 25: SI Unit of Radioactivity
Becquerel (Bq) is the standard SI unit, indicating one decay per second.
Page 26: Other Units of Radioactivity
Curie (Ci), millicurie (mc), microcurie (μc), and Rutherford (rd) are also used to measure radioactivity.
Page 27: Nuclear Medicine L4
Presented by Chris John A. Doria, R.R.T.
Page 28: Radiation Detection Systems
Main types: Gas-Filled Detectors, Scintillators, and Solid-State Detectors.
Page 29: Ion Chambers
Low voltage detectors that measure ion pairs created by radiation interaction, useful in establishing reference standards.
Page 30: Gas Proportional Counters
Measure energies of ionizing radiation, used in discriminating between particle types and accurately measuring doses.
Page 31: Geiger-Muller Counter
Widely used for detecting ionizing radiation, including alpha, beta, and gamma rays.
Page 32: Scintillation Detectors
Utilize material that emits light when exposed to radiation for high sensitivity and spectroscopy.
Page 33: Solid State Detectors
Use semiconductors and measure radiation at a smaller scale, suitable for high levels of exposure.
Page 34: Anger Scintillation Camera
Uses radioactivity and scintillation to map tracers in the body, often employing Technetium-99m.
Page 35: Functions of a Gamma Camera
Crucial for diagnosing various health conditions and monitoring treatments by revealing organ functionality.
Page 36: Operation of a Gamma Camera
Administers a radioactive tracer; images generated by tracking emitted gamma radiation.
Page 37: Emission Computed Tomography
Involves injecting radioactive tracers to visualize physiological properties of the body, including tumors.
Page 38: Single-Photon Emission Computed Tomography (SPECT)
Detects blood flow and activity in organs using emitting nuclides under a rotating camera.
Page 39: Positron Emission Tomography (PET)
Utilizes β+ emitting nuclides for imaging, generating detailed three-dimensional representations of body functions.