User manual

114
Figure 1
Contrast this to the behavior when the same data is fitted to polynomial functions (in
this case 4
th
order) as shown in Figure 2. Obviously the polynomial functions don’t
behave like film – film doesn’t get lighter in color and more transparent at high
doses. Also, polynomial functions are unacceptable because they oscillate between
dose values. The fit with the polynomial function could be improved with additional
dose points, but it takes more time and doesn’t address the fundamental problem.
-40000
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-20000
-10000
0
10000
20000
30000
40000
50000
0 1000 2000 3000 4000 5000
Response
Dose, cGy
Figure 2