Nuclear Medicine and Radioactivity Discovery

Historical Background

• Wilhelm Röntgen discovered X-rays in 1895, earning the first Nobel Prize in Physics in 1901.
• Henri Becquerel discovered natural radioactivity in 1896, observing its effects on photographic plates and paving the way for radiotherapy.
• Marie and Pierre Curie isolated radium from pitchblende in 1898, contributing to luminescent paints and receiving the Nobel Prize in 1903.
• The first human studies using radium as a radiotracer in 1927 marked a significant event in nuclear medicine.
• Ernest O. Lawrence invented the cyclotron in 1934, receiving a Nobel Prize in Physics in 1939 for his contributions.
• Meitner, Strassmann, and Hahn explored nuclear fission in 1938, leading to the creation of the first nuclear reactor, Chicago Pile-1, in 1942.
• George de Hevesy developed radioactive tracers for studies in plants and animals, winning the Nobel Prize in Chemistry in 1943.
• Technetium was isolated in 1937 by Carlo Perrier and Emilio Segre, becoming crucial in nuclear medicine with the development of the 99Mo/99mTc generator.
• The 99mTc generator has become essential for over 15 million medical procedures in the US annually since 1958.

Structure of the Atom

• The nucleus consists of neutrons and protons, with their ratio being vital for stability.
• Electrons occupy distinct orbitals, adhering to rules on occupancy and movement that impact nuclear decay phenomena.
• Atomic symbols consist of mass number (A) and atomic number (Z), representing protons and neutrons.
• The Chart of Nuclides depicts isotopes, isotones, and nuclides, emphasizing the complexity of radioactive elements.

Nuclear Decay Processes

• Over 3,000 nuclides exist, with most being unstable; stability is influenced by the neutron-to-proton (N/Z) ratio.
• Radionuclides with excess neutrons tend to decay by beta-minus (β-) emission, converting a neutron to a proton.
• Conversely, radionuclides with few neutrons decay via beta-plus (β+) emission or electron capture (ε), converting a proton to a neutron.
• Excess energy in unstable nuclei can be released as gamma (γ) rays.
• Electron capture decay occurs in neutron-deficient radionuclides, where an orbital electron is captured by the nucleus.
• Isomeric transition (IT) refers to processes where decay does not lead to the ground state, potentially emitting gamma rays.

Explore the groundbreaking discoveries in nuclear medicine and radioactivity, from Wilhelm Röntgen's X-rays to the first nuclear reactor. This quiz covers the pivotal contributions of scientific figures such as Marie Curie and Ernest O. Lawrence in shaping modern medical science. Test your knowledge on significant milestones that have defined the field.