Problems with Scattered Radiation

Question 1

What is Scattered radiation?

Answer 1

X-rays that have been deflected from the primary beam by an interaction with matter, including the patient, table top and anything else the primary beam may hit.

Question 2

Why is Scattered radiation a problem?

Answer 2

Make the X-ray look indistinct and grey, may be a danger to handlers.

Question 3

Give 3 ways scattered radiation be minimised?

Answer 3

Collimate (limit) the size of the primary beam to the precise area (using light-beam diaphragm), Put a layer of lead-rubber between cassette and table top (X-ray grid), Use high kVp exposure (low mA’s).

Question 4

What is an X-ray grid?

Answer 4

X-ray grid is fine lead strips aligned parallel to direction of primary beam. They allow primary beam to pass through cleanly, and scattered radiation hits.

Question 5

When would you use an X-ray grid? What effect does using an X-ray grid have on mA’s used?

Answer 5

Usually used with larger animals. Increase the X-ray exposure when using a grid to compensate for X-ray absorption. Usually mA’s without grid x 2 = mA with grid.