Surface and build-up dose comparison between Elekta 6  MV flattening filter and flattening-filter-free beams using an advanced Markus ionization chamber and a solid water-equivalent phantom.

Surface and build-up dose comparison between Elekta 6 MV flattening filter and flattening-filter-free beams using an advanced Markus ionization chamber and a solid water-equivalent phantom.
J Appl Clin Med Phys. 2020 Nov 12;:
Authors: Imae T, Takenaka S, Watanabe Y, Aoki A, Matsuda K, Sasaki K, Saegusa S, Nawa K, Nakagawa K, Abe O
Abstract
Using a plane-parallel advanced Markus ionization chamber and a stack of water-equivalent solid phantom blocks, percentage surface and build-up doses of Elekta 6 MV flattening filter (FF) and flattening-filter-free (FFF) beams were measured as a function of the phantom depth for field sizes ranging from 2 × 2 to 10 × 10 cm2 . It was found that the dose difference between the FF and the FFF beams was relatively small. The maximum dose difference between the FF and the FFF beams was 4.4% at a depth of 1 mm for a field size of 2 × 2 cm2 . The dose difference was gradually decreased while the field size was increased up to 10 × 10 cm2 . The measured data were also compared to published Varian FF and FFF data, suggesting that the percentage surface and build-up doses as well as the percentage dose difference between FF and FFF beams by our Elekta linac were smaller than those by the Varian linac.
PMID: 33184970 [PubMed - as supplied by publisher]

Source: Journal of Applied Clinical Medical Physics - November 12, 2020 Category: Physics Authors: Imae T, Takenaka S, Watanabe Y, Aoki A, Matsuda K, Sasaki K, Saegusa S, Nawa K, Nakagawa K, Abe O Tags: J Appl Clin Med Phys Source Type: research