A linear accelerator is calibrated to deliver 1cGy for 1MU at 1.5cm depth with a 10x10cm field size at 100cm SSD. Using the table below, answer the following:

Using interpolation, what is the PDD for 12cm square field at 9.7cm depth? How many MU are needed to delivery 200cGy at 100% isodose line to a calculation point at 7cm depth, and 3cm off axis, for a 12x12cm field at 100cm SSD?

Varian Clinac 21EX(S/N 2081) 6 MV Percent Depth Dose Dosimetry 100 SSD mu set = (prescited dose) /(S,5, NDD Tray TF Wedge TF OAR) \begin{tabular}{ccc} \hline Size & Sc & Sp \\ \hline 3 & 0.924 & 0.976 \\ 4 & 0.943 & 0.980 \\ 5 & 0.069 & 0.984 \\ 6 & 0.967 & 0.967 \\ 8 & 0.995 & 0.993 \\ 10 & 1.000 & 1.000 \\ 12 & 1.010 & 1.006 \\ 15 & 1.017 & 1.014 \\ 20 & 1.026 & 1.023 \\ 25 & 1.035 & 1.031 \\ 30 & 1.036 & 1.037 \\ 40 & 1.052 & 1.043 \end{tabular}