High Frequency
Short Wavelength
electromagnetic
waves
Theire wavelength is the similar size as
the diameter of an atom
Transmitted ny healthy tissue but absorbed by
denser materials like bones and metal.
Affect photographic film in the same way as
light so they can be used tot ake photographs
Diagnose medical conditions:
Bone fractures
Dental problems
CCDs (Charge-coupled devices)
X-rays can be formed electronically using CCDs.
CCDs are silicon chips (size of a post stamp),
divided into a grid of millions of identical pixels.
Detect X-rays and produce electronic signals used to dorm high resolution
images. Same technology is used to take photos in digital cameras.
CT Scans
Computerised Axial Tomography
Produces high resolution images of soft and
hard tissue because Ct scans uses a lot of
x-rays to distinguishbetween the tiny variations
in tissue density
Patient is put insde the cylindrical scanner. Then an x-ray beam is fired through the body
from an X-ray tube and picked up by detectors on the opposite side. The X-ray tube and
deetectors are rotated during the scan. A computer interprets the signals from the detectors
to form an images of a two-dimensional slice through the body.
Multiple two-dimensional CT scans can be put together to
make a three-dimensional image of the inside of the body.
Treat Cancer
X-rays cause ionisation
High doses kill living cells so can be used to
treat cancers
X-rays have to be carefully focused at the right dosage to kill
cancer cells without damaging to many normal cells
1) X-rays are focused on the tumour using a wide beam 2) This
beam is rotated round the patient with the tumour at the centre.
3) This minimises the exposure of normal cells to radiation and
so reduces the chances of damaging thhe rest of the body
Radiographers
Prolonged expore to ionising radiation can be very
dangerous to your health so Radiographers working
with X-ray machines or CT scanners need to take
precautions to minimise their X-ray dose
Precautions taken
Wear lead aprons
Stand behind a lead
screen or leave the
room
Lead used to shield areas of the patient's
body that aren't being scanned
Exposure time is kept to a minimum
Wear Badgess that record the amount of radiation they
are expose to
Means that their radiation dose can be
monitored and regulated