Topic 41

Question 1

What is Conventional linear tomography?

Answer 1

X-ray tube linked with a film on two sides of a pivot table

Moves along the plane

Any objects will cast shadows on the same place on the film.

Question 2

What is axial tomography?

Answer 2

Slice accross the body

Film and tube rotates around the patient’s body

Used in planning cancer treatment

Question 3

What is Computer tomography?

Answer 3

Source moves up and down, exposing slices of the object.

After several rotations, a picture is calcualted

Improved resolution

Barium and Iodine are used to contrast images.

Question 4

Describe image formation using radioisotopes

Answer 4

Used to examine organ and gland function

With use of radioisotopes with short half life.

Question 5

Describe the Gamma Camera

Answer 5

Measures amounts of gamma radiation in an area.If

• E.g. low radiation in part of thyroid, can indicate poor function*
• Uses gamma camera*

Question 6

Describe the rectilinear scanner

Answer 6

Measures radiation distribution

Detector moves along a pattern, connected to a lamp, giving a picture on a film.

Detects at a few cm’s distances

Scans can last over 30 mins

Question 7

What is thermography?

Answer 7

Measurement of body surface temperature

Used in:

Tumour detection, Blood vessel mapping, bone fractures, placental localisation.