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Teachers’ notes for “seeing inside your body”
What happens when you use a mobile phone?
A mobile phone uses
microwaves. Can you
think of something else
which uses microwaves?
0.2C
temperature rise
What might happen if you
use microwaves close to
your head?
A computer can show that
your head might warm up by
0.2ºC with a mobile phone
Do you think this is safe?
Mobile phones use radio waves at a similar energy to a microwave oven. This
means that, it a mobile phone is left on close to your head, the signal could
lead to your body warming up. Medical Physicists have made a computer
simulation which calculates the amount by which the head will warm up. They
found that the maximum change in temperature is about 0.2ºC.
Body temperature is about 37ºC and is held constant between about 36-38ºC
unless there’s a problem like sunstroke or hypothermia. A change of 0.2ºC
therefore appears to be quite significant. However, in practice, body
temperature can change by this amount naturally, so an increase of 0.2ºC is
probably safe.
Research like this has led to the Government recommending that children use
mobile phones for emergency calls only.
Do you feel hot today?
Which do you think are the warmest parts of your face?
This picture shows
a child’s face. It
shows the warmest
parts in red and the
colder parts in blue.
This picture was taken from a thermal imaging camera and shows the
warmest parts of the face in red/white and the coldest in blue.
The warmest parts are the eyes, forehead and lips, which are closest to the
deep parts of the body core; the coldest are the nose, cheeks and chin which
are the parts which stick out most.
The hair is particularly cold as it insulates the head and keeps the heat in.
Images like this are used to investigate parts of the body with poor circulation
which feel cold, or regions of inflammation.
X-ray picture
This is an x-ray
picture of a foot.
People have used a
computer to show
only the bones and
the muscles.
This is a 3D x-ray image of a foot, called a CT scan. A computer has
processed the scan, identified the bone and the muscle and then rebuilt the
image.
What is this an x-ray picture of?
It’s the pelvis. It
shows the hips,
backbone and the
top of the legs.
Another CT scan, this time of the pelvis. Again, a computer has identified the
bones in the image and rebuilt the image.
Ultrasound scan
24 weeks
8 weeks
18 weeks
This is a series of ultrasound scans taken of a foetus at 8, 18 and 24 weeks
gestation.
At 8 weeks, you can see the head, arms and body surrounded by fluid (dark)
and the placenta (a light fuzzy halo around the dark fluid). The baby is about
1 cm long.
At 18 weeks, you can see the face, skull, ribs and heart. The baby is about
12 cm long.
At 24 weeks, you can see the face, structures in the brain and the heart. If
there’s a problem and the baby is born now, it will be about 4 months
premature and will weight as much as a bag of sugar. This is the most
premature that babies can be.
Ultrasound scan of kissing!
Ultrasound can do more than imaging babies. Here, it’s used to image the lips
kissing! This work helps to treat people who have speech problems.
This is a different kind of scan again, called a PET scan. The patient is
injected with a drug and the scanner measures where the drug went. If we
choose a drug which is found in cancer, then we can work out where the
cancer is.
The heart shows up clearly
and the kidneys can be seen.
The brightest area shows
that there is cancer in a rib.
tumour
heart
kidney
This is a picture from a PET scan from somebody who’s been injected with a
drug which flows round the blood stream and collects in a cancer. The heart
and kidneys show up bright, because that’s where there’s a lot of blood, and
the very bright region is a tumour.