Unit 21 Learning Aim A and B Catherine Cherian
Radiation use in medical diagnosis and treatment
X-RAY
What are X-rays? X-rays have high frequencies (3 × 10 16 − 3 × 10 19 Hertz) and
● Explain in terms of energy, short wavelengths (10-8 to 10-11 m) and are part of the
frequency, and penetrating electromagnetic spectrum. They have high levels of energy, which
properties. makes them very useful in medicine.
● Show their place in the In 1895, when Röntgen placed a piece of lead in front of the
electromagnetic spectrum. electron-discharge tube, Wilhelm Roentgen inadvertently
● How were X rays discovered? discovered x-rays, blocking the rays, but he was surprised to see
his own flesh flickering around his bones on the fluorescent screen
● What are X rays used for?
behind his hand.
Then he put the photographic film between his hand and the
projector and captured the first X-ray shot of the world.
The majority of areas of the body can be studied using X-rays. They
are used mostly to look at the bones and joints, but often they are
used to classify conditions that involve soft tissue, such as internal
organs. Bone fractures and cracks are complications that can be
found during an X-ray.
How are X rays produced? In medicine, because of the harm that can
● Labelled diagram of the X ray be caused by X-rays on healthy tissue,
tube caution is taken to minimise patient
o What are exposure. In order to penetrate flesh and
characteristic X rays not bone, X-rays can differ in energy and
o What is often be absorbed by denser diseased
tissue so that it shows up clearly on
Bremsstrahlung/Braki
photographic film. In body tissues, lower intensity (longer
ng X rays
wavelength) X-rays are absorbed more quickly than higher energy
o Sketch a typical X ray X-rays, which have more penetration. When they travel, the X-rays'
spectrum average intensity decreases as the distance increases. An example
● X ray imaging: of an inverse square relationship, where the strength of the X-rays
o Digital radiography falls to 1/4 of its original value as the distance travelled is doubled,
o Fluoroscopy is the same relationship. X-rays are passed through a thin metal
o Mammography plate before passing through the patient to minimise absorption of
lower-energy X-ray photons by healthy tissue. The tissues would
heat up and become damaged if this was not done. As with other
electromagnetic waves, as they travel, X-rays spread out. If the
distance increases , the average strength of the X-rays decreases.
An example of an inverse square relationship, where the strength of
the X-rays falls to 1/4 of its original value as the distance travelled is
doubled, is the same relationship.
A line spectrum with many discrete energies is produced by
characteristic radiation, while Bremsstrahlung generates a
continuous spectrum of photon energies over a specific range.
Digital radiography: Digital
radiography (DR) is an advanced x-ray inspection form that instantly
creates a digital radiographic image on a computer. In order to
collect data during object analysis, this technique uses x-ray
sensitive plates which are automatically transferred to a device
without using an intermediate cassette.
Fluoroscopy: Fluoroscopy is a type of medical imaging that,
much like an X-ray film, displays a continuous X-ray image on a
monitor. An X-ray beam is distributed through the body during a
Radiation use in medical diagnosis and treatment
X-RAY
What are X-rays? X-rays have high frequencies (3 × 10 16 − 3 × 10 19 Hertz) and
● Explain in terms of energy, short wavelengths (10-8 to 10-11 m) and are part of the
frequency, and penetrating electromagnetic spectrum. They have high levels of energy, which
properties. makes them very useful in medicine.
● Show their place in the In 1895, when Röntgen placed a piece of lead in front of the
electromagnetic spectrum. electron-discharge tube, Wilhelm Roentgen inadvertently
● How were X rays discovered? discovered x-rays, blocking the rays, but he was surprised to see
his own flesh flickering around his bones on the fluorescent screen
● What are X rays used for?
behind his hand.
Then he put the photographic film between his hand and the
projector and captured the first X-ray shot of the world.
The majority of areas of the body can be studied using X-rays. They
are used mostly to look at the bones and joints, but often they are
used to classify conditions that involve soft tissue, such as internal
organs. Bone fractures and cracks are complications that can be
found during an X-ray.
How are X rays produced? In medicine, because of the harm that can
● Labelled diagram of the X ray be caused by X-rays on healthy tissue,
tube caution is taken to minimise patient
o What are exposure. In order to penetrate flesh and
characteristic X rays not bone, X-rays can differ in energy and
o What is often be absorbed by denser diseased
tissue so that it shows up clearly on
Bremsstrahlung/Braki
photographic film. In body tissues, lower intensity (longer
ng X rays
wavelength) X-rays are absorbed more quickly than higher energy
o Sketch a typical X ray X-rays, which have more penetration. When they travel, the X-rays'
spectrum average intensity decreases as the distance increases. An example
● X ray imaging: of an inverse square relationship, where the strength of the X-rays
o Digital radiography falls to 1/4 of its original value as the distance travelled is doubled,
o Fluoroscopy is the same relationship. X-rays are passed through a thin metal
o Mammography plate before passing through the patient to minimise absorption of
lower-energy X-ray photons by healthy tissue. The tissues would
heat up and become damaged if this was not done. As with other
electromagnetic waves, as they travel, X-rays spread out. If the
distance increases , the average strength of the X-rays decreases.
An example of an inverse square relationship, where the strength of
the X-rays falls to 1/4 of its original value as the distance travelled is
doubled, is the same relationship.
A line spectrum with many discrete energies is produced by
characteristic radiation, while Bremsstrahlung generates a
continuous spectrum of photon energies over a specific range.
Digital radiography: Digital
radiography (DR) is an advanced x-ray inspection form that instantly
creates a digital radiographic image on a computer. In order to
collect data during object analysis, this technique uses x-ray
sensitive plates which are automatically transferred to a device
without using an intermediate cassette.
Fluoroscopy: Fluoroscopy is a type of medical imaging that,
much like an X-ray film, displays a continuous X-ray image on a
monitor. An X-ray beam is distributed through the body during a
