History of Radiology and Radioactivity

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Questions and Answers

What term is used to describe isomeric states with longer half-lives?

Metastable states (correct)

Excited states

Isomeric decay states

Stable states

What phenomenon occurs when an excited state transitions to a lower energy state?

Isomeric transition (correct)

Gamma emission

Alpha decay

Isomeric decay

In the example of metastable 99mTc decaying to 99Tc, what energy form is primarily emitted?

Alpha particles

Neutrons

Beta particles

Conversion electrons (correct)

What does the branching ratio (B.R.) represent in radioactive decay?

The fraction of decays through a specific pathway Signup and view all the answers

What type of elements are primarily associated with alpha emission?

Heavy elements such as Uranium Signup and view all the answers

Who discovered natural radioactivity in 1896?

Henri Becquerel Signup and view all the answers

What is the SI unit for measuring radioactivity?

Becquerel Signup and view all the answers

Who was the first to use a radiotracer for a diagnostic procedure?

George de Hevesy Signup and view all the answers

In what year did Henri Becquerel share the Nobel Prize in Physics?

1903 Signup and view all the answers

Which of the following substances was isolated by Marie and Pierre Curie in 1898?

Radium Signup and view all the answers

What significant achievement is associated with the construction of Chicago Pile-1?

First nuclear reactor Signup and view all the answers

Which element was discovered by Carlo Perrier and Emilio Segre in 1937?

Technetium Signup and view all the answers

What exposure led to the development of radiotherapy, as observed by Becquerel?

Leaving radium in his vest pocket Signup and view all the answers

For which scientific contributions did George de Hevesy win the Nobel Prize in Chemistry?

Development of radioactive tracers Signup and view all the answers

What non-SI unit of radioactivity is equal to the number of atoms in a one g sample of radium-226 that decay in one second?

Curie Signup and view all the answers

What year was the cyclotron invented?

1934 Signup and view all the answers

Who took the first medical X-ray in 1895?

Wilhelm Röntgen Signup and view all the answers

What significant discovery did Meitner, Strassmann, and Hahn make in 1938?

Fission of uranium nuclei Signup and view all the answers

Which study by Blumgart and Weiss in 1927 focused on the human body's function?

Investigated blood flow velocity Signup and view all the answers

Which isotope did George de Hevesy use to study water metabolism?

2H Signup and view all the answers

What annual award is presented by the SNMMI Cardiovascular Council?

Hermann Blumgart Award Signup and view all the answers

What is the mass number of the nuclide represented by the symbol 9F?

18 Signup and view all the answers

Which process typically occurs in radionuclides with excess neutrons?

β- emission Signup and view all the answers

What happens to the atomic number (Z) during β- decay?

Z increases by 1 Signup and view all the answers

What is the relationship between atomic number (Z) and proton number in a nuclide?

Z is equal to the number of protons Signup and view all the answers

What is emitted along with a β- particle during β- decay?

An antineutrino Signup and view all the answers

What defines a radionuclide?

A nuclide that is radioactive Signup and view all the answers

In β+ decay, what is the change in atomic number (Z)?

Z decreases by 1 Signup and view all the answers

What percentage of the time does 18F decay by electron capture (ε)?

3% Signup and view all the answers

How does the N/Z ratio influence nuclear stability?

A higher N/Z ratio may lead to β- decay Signup and view all the answers

What is typically true about the energy distribution of β- particles?

Mean β- energy is approximately one-third of the maximum energy Signup and view all the answers

Which of the following particles is produced during β+ emission?

Positron Signup and view all the answers

What is the total energy of the transition (Q) during the decay process?

970.8 keV Signup and view all the answers

What occurs when a nucleus releases energy in the form of γ rays?

Decay to a more stable state Signup and view all the answers

Which type of nuclide has the same neutron number but different atomic numbers?

Isotone Signup and view all the answers

What is emitted along with a β+ particle during β+ decay?

A neutrino Signup and view all the answers

In the decay process, which particles are emitted when a neutron-rich radionuclide decays?

Proton and antineutrino Signup and view all the answers

Study Notes

Historical Background

Wilhelm Röntgen discovered X-rays in 1895, receiving the first Nobel Prize for Physics in 1901.
Henri Becquerel discovered natural radioactivity in 1896, leading to the identification of beta particles and contributing to cancer radiotherapy innovations.
Marie and Pierre Curie isolated radium in 1898 from pitchblende, facilitating advances in radioactive applications until the 1960s.
The Curie unit measures radioactivity equivalent to the decay rate in a 1g sample of radium-226 (3.7 x 10^10 dps).
Blumgart and Weiss introduced radiotracer techniques in 1927 for measuring blood flow, laying the foundation for nuclear cardiology.
The cyclotron, invented by Ernest O. Lawrence in 1934, enabled the acceleration of particles, earning him a Nobel Prize in 1939.
The first nuclear reactor, Chicago Pile-1, was developed by Enrico Fermi in 1942, demonstrating the potential for nuclear chain reactions.

Tracer Principle

George de Hevesy used radioactive tracers, winning the Nobel Prize in Chemistry in 1943 for exploring chemical processes in living organisms.
His method involved tracing food through radioactivity, leading to insights in biological research.

Discovery of Technetium

Technetium was isolated in 1937 by Carlo Perrier and Emilio Segrè from a molybdenum sample in the Berkeley cyclotron, marking the identification of element 43.

Atomic Structure

Each atomic symbol includes a mass number (A) representing protons plus neutrons, and an atomic number (Z) indicating the number of protons.
A nuclide is defined by specific mass number and atomic number, with radionuclides being radioactive forms.

Nuclear Stability

Over 3,000 nuclides exist, with most being unstable; stability is influenced by the neutron-to-proton (N/Z) ratio.
Neutron-rich radionuclides often undergo β- emission, converting neutrons to protons, while neutron-deficient radionuclides decay via β+ emission or electron capture.

Nuclear Decay Processes

β- emission: Involves a neutron transforming into a proton, emitting a β- particle and an antineutrino. This increases atomic number (Z) by 1 and decreases neutron number (N) by 1.
β+ emission: A proton converts to a neutron, emitting a β+ particle and a neutrino, decreasing Z by 1 and increasing N by 1.
Isomeric transitions occur when excited states decay to lower energy states, often emitting γ rays or conversion electrons.

Decay Modes

Alpha emission primarily happens in heavy elements that need to lose mass for stability. The resulting alpha particles are highly energetic and associated with short-range energy deposition.
Multiple decay pathways, characterized by branching ratios, can occur simultaneously in the same nucleus.

Key Definitions

Isotopec: Atoms with the same Z (number of protons) but different N (number of neutrons).
Isotones: Atoms with the same N but different Z.
Isobars: Atoms with the same combined Z + N.

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Description

This quiz covers significant milestones in the discovery of radiation and its applications, including the work of Röntgen, Curie, and Fermi. Test your knowledge on the principles behind radioactivity and the advancements in nuclear technology up to the mid-20th century.