Draw an ionisation chamber.
 What is it measuring?
 Where is the charge collected?
 What effects do temperature and pressure have on the readings?
 Prior to an Sr-90 check, what else do you need to consider about the electrometer? (Leakage test).
 Asked about the Heel Effect on the orthovoltage machine? What is it, explain the curve and how do we overcome this is our measurements?
 Draw an electron depth dose curve.
 Explain each part of the curve.
 How does the curve vary with energy? Why?
 Draw a treatment head (linac).
 What are the purposes of the secondary collimators?
 How is the field size defined? Is it a 10 x 10 cm field at the isocentre or at 100cm FSD?
 How would you measure the field size? Film? (50%).
 Can you determine the beam flatness from this film?
 How would you do that?
 Asked about head scatter measurements. Why are they performed?
 Are they utilised in the treatment planning system?
 Why do we do dmax profile scans and measurements?
 If you had a particular area of a field blocked out, how would you calculates the required treatment time?