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Corrected relationship between % dd ( 10 ) x and stopping‐power ratios
Author(s) -
Rogers D. W. O.,
Yang C. L.
Publication year - 1999
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.598554
Subject(s) - stopping power , power (physics) , nuclear medicine , dosimetry , physics , medicine , optics , thermodynamics , detector
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 × 10 cm 2field on the surface of a phantom at SSD = 100 cm . This relationship has been used to calculate extensive tables of k Qfactors 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 ̄ / ρ ) 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 Qis less than 0.2%.