Source of Support: None, Conflict of Interest: None
Accurate determination of Zero-Area Tissue-Maxmimum Ratio (TMR) is a pre-requisite for using Scatter-Function dose computation model for estimating the dose in a phantom irradiated by photon beams. In the current study, zero-area TMRs have been experimentally determined by measuring the narrow beam attenuation curve in scatter free conditions for 60co, 6, and 10 MV photon beams. The measured zero-area TMR
values were cross-verified by two independent procedures and were found to be in good agreement. These measurements along with the conventional measurements of TMRs allow an accurate determination of SMR values.