1996 KV Code of Practice

Question 1

How is medium energy defined?

Answer 1

0.5-4 mm Cu HVL (or above 8 mm Al), 160-300 kV

Question 2

How is low energy defined?

Answer 2

1-8 mm Al HVL, 50-160 kV

Question 3

How is very low energy defined?

Answer 3

0.035-1 mm Al HVL, 8-50 kV

Question 4

What medium and depth should absolute dose measurement for medium energy be done at?

Answer 4

Chamber 2 cm deep in a full scatter water phantom, SSD of applicator, 10x10 (or equiv. circle) , chamber separation 3 cm adequate, simultaneous irradiation.
OR
In air, eqn. for air.

Question 5

What is the equation for absorbed dose for medium energy?

Answer 5

Dw, z=2 = M Nk kch [(uen/p)w/air]z=2, phi

Question 6

What is kch?

Answer 6

A factor which accounts for the change in the response on the ion chamber between calibration in air and measurement in a phantom.

Question 7

What is geometric mean?

Answer 7

[Ms/Mf]t = sqrt([Ms/Mf]a[Ms/Mf]b

Question 8

How many position changes and exposures should be done at the minimum?

Answer 8

At least one exchange, then whole thing repeated at least once - meaning 6 exposures in each position per chamber.

Question 9

What medium and depth should absolute dose measurement for low energy be done at?

Answer 9

Chamber free in air, 3 cm separation adequate, 7 cm circle or 7x7 field approximately, simultaneous irradiation

Question 10

What is the equation for absorbed dose for low energy?

Answer 10

Dw, z=0 = M Nk Bw [(uen/p)w/air]air

Question 11

What medium and depth should absolute dose measurement for very low energy be done at?

Answer 11

Irradiating in turn or simultaneously in water equivalent phantom,

Question 12

What is the equation for absorbed dose for very low energy?

Answer 12

Dw, z=0 = M Nk kch [(uen/p)w/air]z=0, phi

Question 13

Where are the kch values?

Answer 13

In the addendum