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Reading comprehension: THE HISTORY OF RADIOTHERAPY

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The History of Radiotherapy
Radiotherapy uses precisely targeted high-energy rays to kill cancer cells. It does this by
damaging a cell's internal components (molecules), causing the cells to commit suicide
by apoptosis. When a high-energy ray hits a molecule, it can cause it to break up. This can
form free radicals, which can cause further damage to the inside of the cell.
Some rare metals, for example radium, emit high-energy gamma-rays naturally. In other cases,
radiation can be produced in a special machine, where a metal element is heated to
produce electrons. These accelerate in an electric field towards a piece of tungsten metal,
which then emits high-energy x-rays when they hit it.
Wilhelm Röntgen, a German physics professor, discovered x-rays in 1896. He gave a lecture
called "Concerning a New Type Of Ray", which caused a revolution in the scientific community.
Just weeks later, Emil Grubbé, a student doctor in Chicago, became the first person to use of
radiation to treat cancer. And three years later, two Swedish doctors used radiotherapy to
cure several cases of head and neck cancer. In 1901, Röntgen was awarded the Nobel Prize for
his discovery.
Early radiotherapy consisted of a single massive dose of radiation, typically lasting an hour.
Side effects were severe. In 1914, an Austrian doctor controversially suggested that
radiotherapy might work better if it was given in many smaller doses ('fractionated
radiotherapy'). This sparked a debate that lasted until 1922, when Claudius Regaud
conclusively proved that fractionated therapy was just as effective as single-dose therapy, but
caused fewer side effects.
The 1920s also saw the emergence of the radiographer as a specialist profession. Despite these
advances, radiotherapy was predominantly used to alleviate symptoms ('palliative' treatment)
rather than actually cure cancer.
Over the next thirty years, engineers built ever more powerful x-ray sources. The more
powerful an x-ray, the further into the body it penetrates and the less damage it does to the
skin. X-ray energies are measured in Kilovolts (KV) or Megavolts (MV; 1MV = 1000KV).
In the 1920s, x-ray generators were only capable of making x-rays at about 200KV (for
comparison, the natural gamma-rays emitted by radium are about 1.2MV). By the 1950s,
engineers had developed an 8MV x-ray generator (or 'linear accelerator'). Nowadays, an x-ray
machine in a typical hospital will have an energy of about 10MV.
Since then, a number of technological developments have allowed radiologists to target the xray beam more accurately and avoid damaging normal tissue, further improving radiotherapy
as a cancer treatment.
For example, the use of CT scanning allows radiologists to determine the exact size and shape
of the tumour. Another type of radiotherapy is internal radiotherapy or brachytherapy. This
technique involves implanting tiny beads or rods of radioactive metal around the tumour. It
too has been in use since the early 1900s, and is still in use today. Initially, radium was the
metal of choice for brachytherapy, but these days, caesium and iridium are used instead.
Radiotherapy is usually required for one of the following reasons: As a stand-alone treatment
to cure cancer; To shrink a cancer before surgery; To reduce the risk of a cancer coming back
after surgery; To complement chemotherapy; To control symptoms and improve quality of life
if a cancer is too advanced to cure.
1. Match some of the words from the text with the definitions below.
a) A region of space in which a force acts. (Paragraph 2)
b) An often harmful effect, as of a drug, secondary to the intended effect. (Paragraph
4)
c) To make easier to endure; lessen; mitigate. (Paragraph 5)
d) A ray or stream of light or other radiation, as subatomic particles. (Paragraph 8)
e)
A long straight stick, wand, or staff. (Paragraph 9)
2. Say if the following statements are true, false. Argue each of your answer either if
they are true or false.
a) Radiation harms the molecules that form the cells.
b) Wilhelm Röntgen was the first person to use radiation to treat cancer.
c) Fractioned therapy is safer than single massive therapy.
d) Trough CT scanning we can see the cancer’s outline.
e) Brachytherapy is an intrusive technique.
3. Why are the most powerful x-rays less harmful?
4. What elements are used in internal radiotherapy nowadays?
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