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Questions and Answers
What is the primary hazard of beta particles?
What is the primary hazard of beta particles?
Which type of isotopes are radioactive and emit radiation?
Which type of isotopes are radioactive and emit radiation?
How can gamma rays be best described?
How can gamma rays be best described?
Which decay mode involves a heavy nucleus splitting into two fragments?
Which decay mode involves a heavy nucleus splitting into two fragments?
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What do stable isotopes have in common?
What do stable isotopes have in common?
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Which particle has no charge and the same mass as a proton?
Which particle has no charge and the same mass as a proton?
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Which of the following processes is least probable in uranium-238?
Which of the following processes is least probable in uranium-238?
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What distinguishes metastable nuclei from other nuclei?
What distinguishes metastable nuclei from other nuclei?
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What happens to the atomic number of an atom during alpha decay?
What happens to the atomic number of an atom during alpha decay?
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Which type of decay occurs when there are too many neutrons in an atom?
Which type of decay occurs when there are too many neutrons in an atom?
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What is emitted during beta plus (β+) decay?
What is emitted during beta plus (β+) decay?
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What does the mass number of an atom do during alpha decay?
What does the mass number of an atom do during alpha decay?
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What contributes to the energy difference between parent and daughter nuclides in beta decay?
What contributes to the energy difference between parent and daughter nuclides in beta decay?
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How is the range of alpha particles in matter described?
How is the range of alpha particles in matter described?
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What is the consequence of a neutron converting into a proton during beta decay?
What is the consequence of a neutron converting into a proton during beta decay?
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What defines an atom as ionized?
What defines an atom as ionized?
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What is required for positron decay to occur?
What is required for positron decay to occur?
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Which particles constitute an alpha particle?
Which particles constitute an alpha particle?
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Which type of radiation is capable of removing electrons from atoms?
Which type of radiation is capable of removing electrons from atoms?
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What is a characteristic of isotopes?
What is a characteristic of isotopes?
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What are isobars?
What are isobars?
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What type of radiation includes visible light and microwaves?
What type of radiation includes visible light and microwaves?
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How does technetium-99m decay?
How does technetium-99m decay?
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Which of the following statements about isotones is true?
Which of the following statements about isotones is true?
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What is produced when a positron combines with an atomic electron?
What is produced when a positron combines with an atomic electron?
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What happens to the atomic number of the daughter nuclide during electron capture?
What happens to the atomic number of the daughter nuclide during electron capture?
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In which cases can both electron capture and positron decay occur?
In which cases can both electron capture and positron decay occur?
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Which equation represents the relationship between activity, decay constant, and the number of radioactive atoms?
Which equation represents the relationship between activity, decay constant, and the number of radioactive atoms?
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What does the decay constant (λ) represent in radioactive decay equations?
What does the decay constant (λ) represent in radioactive decay equations?
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What is the equation to calculate the half-life (T1/2) in terms of the decay constant (λ)?
What is the equation to calculate the half-life (T1/2) in terms of the decay constant (λ)?
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What does the average (mean) lifetime (Ƭ) represent for radioactive atoms?
What does the average (mean) lifetime (Ƭ) represent for radioactive atoms?
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What defines the effective half-life (Te) of a radiopharmaceutical?
What defines the effective half-life (Te) of a radiopharmaceutical?
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Study Notes
Types of Radiation and Radioactivity
- Radiation is classified as ionizing or non-ionizing, based on its ability to ionize matter
- Ionizing radiation possesses enough energy to remove an electron from an atom or molecule
- Non-ionizing radiation lacks the energy to separate molecules or remove electrons
- Types of ionizing radiation include particulate (alpha, beta, and neutron) and electromagnetic (gamma rays)
- Alpha particles are helium nuclei (2 neutrons and 2 protons), positively charged, and have low penetration power (stopped by paper)
- Beta particles are high-speed electrons or positrons; they are negatively or positively charged and have moderate penetration power (stopped by a few millimeters of material)
- Neutrons have no charge and the same mass as protons; they have high penetration power
- Gamma rays are electromagnetic radiation with no charge and no mass; high penetration power (stopped by thick lead or concrete)
- Radioactive decay processes allow unstable atomic nuclei to reach a stable configuration. These processes include alpha, beta, and electron capture
- A radionuclide decays to a more stable configuration via various modes, including spontaneous fission; isomeric transition; alpha, beta, positron decay; and electron capture
- Spontaneous fission occurs in heavy nuclei that break into smaller nuclei
- Alpha decay decreases atomic number by two and mass number by four
- Beta decay converts a neutron into a proton, increasing the atomic number by one
- Electron capture combines an inner-shell electron with a proton, lowering the atomic number by one
- The difference in energy between the parent and daughter nuclides is called the transition or decay energy
- The half-life (T1/2) is the time needed for half of the radioactive nuclei to decay, calculated as 0.693/λ (decay constant)
Isotopes
- Isotopes of a given element contain the same number of protons but varying numbers of neutrons
- Most elements have more than one stable isotope
- Stable isotopes are non-radioactive and occur naturally
- Radioisotopes are radioactive and emit radiation. Some are natural, and others are artificially created
Isobars
- Isobars are atoms with different numbers of protons and different numbers of neutrons, but the same total number of nucleons.
Isotones
- Isotones are atoms with different atomic numbers and different mass numbers with constant (A-Z) value; they contain the same number of neutrons.
Isomers
- Isomers are identical atoms, but they exist at different energy states due to differences in nucleon arrangements
- Technetium-99m decays to technetium-99, with the emission of a 140-keV gamma ray, useful in nuclear medicine
Radioactive Decay Laws
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Radioactive decay is the process by which an unstable nucleus loses energy by emitting radiation. A material holding unstable nuclei is radioactive.
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The radioactive decay described by A = A₀e⁻ -λt. Where: -A is the activity present after time t. -A₀ is the initial activity at time equals zero. -λ is the decay constant in time. -t is the time taken to change activity from A to A.
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Mean life time T=1/λ
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T1/2= 0.693/λ
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Units of radioactivity: Curie (Ci) = 3.7 × 10¹⁰ disintegrations/sec, and Becquerel (Bq) = 1 disintegration/sec.
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1 Ci = 3.7 x 1010 Bq
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The concept of half-life is essential for radiologic science. It's used in nuclear medicine and x-ray terminology, with the half-value layer as a parallel component. 3.3 half-lives equal 1/10 life.
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In any biologic system, the loss of a radiopharmaceutical is due to two factors: physical decay of the radionuclide and biological elimination of the radiopharmaceutical. The effective rate (λe) of loss is related to λp (physical rate) and λb (biological rate).
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Description
This quiz explores the different types of radiation, including ionizing and non-ionizing forms. Learn about alpha, beta, and gamma radiation, their characteristics, and their penetration abilities. Test your knowledge on radioactivity and its implications in various contexts.
