“…For the dosimetry of low energy therapeutic x-ray beams, the accepted 'gold standard' is the Farmer type cylindrical ionisation chamber (Evans et al, 2001;Healy et al, 2005;Hill et al, 2007Hill et al, , 2005Hill et al, , 2009Jurado et al, 2005;Li et al, 1997;Ma et al, 1998). This is consistent with the recommendations listed in the reference dosimetry protocols for kilovoltage x-ray beams (Aukett et al, 2005Ma et al, 2001).…”