A method of measuring the field output factor based on daisy–chaining

Abstract

Objective improve the accuracy of the measurement results by using the field output factor measurement method based on daisy-chaining. Methods The Varian Edge Accelerator 6 MV X-ray data were measured using the IBA CC13 ionization chamber, IBA CC01 ionization chamber, IBA Razor semiconductor detector, IBA EFD semiconductor detector and Gafchromic EBT3 film, respectively. Results Compared with the daisy-chaining measurement method, the results obtained by the conventional measurement method using CC13 were smaller. The deviation value was 16.71% in the 1 cm × 1 cm field. The measurement results in a larger field via CC01 were bigger with a deviation of 8.39% in the 40 cm × 40 cm filed. The measurement results via Razor in a larger field were larger with a deviation of 9.40% in the 40 cm × 40 cm field. The measurement results were similar between EFD and Razor with a deviation of 9.14% in the 40 cm × 40 cm field. The results of the film measurement were equivalent to those obtained from the daisy-chaining method in a field of> 1 cm × 1 cm with a deviation within 1.60%, whereas the deviation was increased to 3.13% in the 1 cm × 1 cm field. The results were consistent with daisy-chaining measurement if the 3 cm × 3 cm or 4 cm × 4 cm fields were selected as the intermediate fields with the maximum deviation of 0.29%. Conclusions For the detectors with changing response along with the field size, daisy-chaining measurement method can be utilized to extend the measurement range and improve the accuracy of the measurement results. Key words: Daisy-Chaining; Output factor; Measurement method