Abstract
A polynomial formula, deduced from the data published by Mills et al. [Med. Phys. 12, 473 (1985)], in predicting the relative electron beam output factors, is presented in this report. This formula contains four parameters. By choosing four measured output factors, from four field sizes normalized at the field size of (10,10), the values of these parameters can be determined. A comparison of the factors predicted with this formula and the values measured by Mills et al. shows that the differences between the field sizes of (4,4) to (30,30) are 0.5% or less in 31 out of 35 field sizes. All the 35 field sizes are within 1% for an electron beam of 20 MeV. With 6-MeV electron beams, the differences are 0.5% or less in 26 out of 35 field sizes, and 1% or less in 31 out of 35 field sizes. Those having differences greater than 1% have either a small field size (5 cm) or a large field size (20 cm). Considering that this formula requires only four accurately measured relative output factors, one can predict the factors of any field within an acceptable accuracy. The calculation is easy with a scientific hand calculator. This formula provides major improvement over the other methods which require many measurements to be taken in order to interpolate with acceptable accuracy.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.