1) Highest neutron flux in a therapy treatment room is produced by _____.
ANSWER: D a 20-MV photon beam
2) In the treatment of Hodgkin s disease with a mantle field on a linac, patients may experience a skin reaction in the neck region. This could be due to which of the following?
ANSWER: D All of the above
3) Parallel-opposed 18 MV photon beams (dmax = 3.5 cm) are used to treat an area which includes nodes at a minimum depth of 2.0 cm, If the nodes are to receive at least 90% of the midplane dose:
ANSWER: D Bolus is not needed.
4) Which of the following could be used as a tissue compensator?
ANSWER: E All of the above
5) The formula used to calculate the gap on the skin between adjacent fields, matched at depth, relies on the fact that:
ANSWER: B The projection of the edge of the light field follows the 50% decrement line of the radiation field.