Figure 11 compares the present results to results that would be obtained using previous protocols and the data in them. The change from TG-21 values is not large, and mostly accounted for by the change in the underlying stopping powers being used now. However, the difference would be slightly larger if there were no aluminum electrode since this was not considered in TG-21 and it affects this chamber. Also, part of the difference comes from the uncertainty introduced by interpolating the previous AAPM data which was presented as a function of whereas here is used. The IAEA values differ considerably because of how they treated beams as a special case.
Results use eq.
Part of the difference for TG-21 is that previous data are tabulated vs and require a conversion from to . The current results are also shown using this approach to show the variations introduced. It will be made available via the WWW at the address given at the beginning of this references.