Short answers, pulled from the story.
Wilhelm Röntgen discovered X-rays in 1895, which eventually birthed the field of radiation therapy. Emil Grubbe of Chicago became possibly the first American physician to use these rays to treat cancer in 1896.
Radiation therapy works by damaging the DNA of cancer cells through direct ionization or indirect ionization via free radicals formed from water molecules. This process creates hydroxyl radicals that attack the DNA chain leading to mitotic catastrophe and cell death.
Megavoltage X-ray units were first built in the late 1930s but cost limited their use to few institutions. One early unit installed at St. Bartholomew's hospital in London in 1937 used a 30-foot long X-ray tube and weighed 10 tons.
Medical linear particle accelerators developed since the 1940s began replacing older units in the 1980s. The first medical linear accelerator was used at Hammersmith Hospital in London in 1953.
The FDA approved Lutathera for pediatric patients aged 12 or older with somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumours in April 2024. This drug uses isotopes like lutetium-177 for treating such tumors.