Chinese Journal of Radiation Oncology 2017;26(9):1077-1079

doi:10.3760/cma.j.issn.1004-4221.2017.09.019

A comparative study of measurement of small field data and calculation based on Monte Carlo method

Ning CHEN ; Jianliang ZHOU ; Jie QIU ; Bo YANG ; Tingtian PANG ; Nan LIU ; Xia LIU ; Lang YU ; Wenbo LI ; Tingting DONG ; Fuquan ZHANG

Keywords

Small field; Detectors; Monte Carlo

Country

China

Language

Chinese

Abstract

Objective To compare the relative dose of small fields measured by clinically common detectors and those obtained from Monte Carlo simulation in order to obtain the accurate measurement method, and to modify the inappropriate detectors.Methods The percentage depth-dose distribution curve and profile (flatness and symmetry) curves were collected at 2 cm×2 cm, 3 cm×3 cm, and 4 cm×4 cm under 6-MV X-ray of Trilogy linear accelerator by CC13, PFD, SFD, and blue phantom.The results were compared with the stimulation results from Monte Carlo method (the current gold standard).The correction factors for the detectors with large error were calculated to provide reference data for clinical practice.Results The results measured by SFD detector were most close to the results from Monte Carlo simulation.The measurement errors of CC13 and PFD detectors were large.The correction factor in the penumbra for CC13 and PFD detector was 0.664-1.499.Conclusions SFD detector is better than CC13 and PFD detector in the measurement of small fields, but CC13 and PFD detector can provide reference data for clinical practice after the corresponding correction.