Corrected relationship between %dd(10)x and stopping-power ratios

Kosunen and Rogers [Med. Phys. 20, 1181-1188 (1993)] presented a linear equation relating the Spencer-Attix water/air stopping power ratio to %dd(10)(x), the photon component of the percentage depth-dose at 10 cm depth for a 10 X 10 cm(2) field on the surface of a phantom at SSD = 100 cm. This relationship has been used to calculate extensive tables of k(Q) factors for use with dosimetry protocols based on absorbed-dose calibration factors. Unfortunately, the original paper contained an error which has recently been assessed (Yang et al.). The present paper presents a corrected form of this relationship, viz.: ((L) over bar/rho)(air)(water) 1.275 - 0.00231[ % dd( 10)(x)] which is based on corrected values of %dd(10)(x). It is shown that despite changes of up to 2% in calculated values of %dd(10)(x), the net effect on calculated values of k(Q) is less than 0.2%. [S0094-2405(99)01204-3].