Download Problems with X-ray Imaging – Solutions!

Problems with X-ray Imaging – Solutions!
1) Image Intensification
 An intensifying screen is placed either side of the p_____________ film
 When _____ photons hit crystals in this screen, the atoms become excited,
then relax back o their ground state and fluoresce (emit visible light photons)
 Photographic film is much more efficient at absorbing these v______ light
photons rather than x-ray photons
 This gives more con_____ but not a clearer image
 Also, less x-rays are required so less ex_______ for patient
2) A Contrast Medium is applied
 Patients can be asked to swallow, are given an enema, or are injected with an
X-ray absorbing substance.
 These will be substances with a high atomic number e.g. Barium Sulphate. This
is called a Barium meal and it allows soft tissues to be imaged.
3) Use a Photocathode (make it Digital)
 Rather than using photographic film, a phosphor screen backed by a
photocathode is used.
 When visible light photons hit the photocathode, an electron is produced,
creating an electrical signal that is sent to a computer.
 This allows a changing image to be viewed.
Problems with X-ray Imaging – Solutions!
1) Image Intensification
 An intensifying screen is placed either side of the p_____________ film
 When _____ photons hit crystals in this screen, the atoms become excited,
then relax back o their ground state and fluoresce (emit visible light photons)
 Photographic film is much more efficient at absorbing these v______ light
photons rather than x-ray photons
 This gives more con_____ but not a clearer image
 Also, less x-rays are required so less ex_______ for patient
2) A Contrast Medium is applied
 Patients can be asked to swallow, are given an enema, or are injected with an
X-ray absorbing substance.
 These will be substances with a high atomic number e.g. Barium Sulphate. This
is called a Barium meal and it allows soft tissues to be imaged.
3) Use a Photocathode (make it Digital)
 Rather than using photographic film, a phosphor screen backed by a
photocathode is used.
 When visible light photons hit the photocathode, an electron is produced,
creating an electrical signal that is sent to a computer.
 This allows a changing image to be viewed.