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Technical Note: A feasibility study of using the flat panel detector on linac for the kV x‐ray generator test
Author(s) -
Cai Bin,
Dolly Steven,
Kamal Gregory,
Yaddanapudi Sridhar,
Sun Baozhou,
Goddu S. Murty,
Mutic Sasa,
Li Hua
Publication year - 2018
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 - 10.1002/mp.12941
Subject(s) - imaging phantom , detector , linearity , flat panel detector , linear particle accelerator , image quality , optics , robustness (evolution) , scanner , voltage , x ray detector , quality assurance , nuclear medicine , computer science , physics , electronic engineering , electrical engineering , artificial intelligence , medicine , engineering , beam (structure) , external quality assessment , pathology , image (mathematics) , biochemistry , chemistry , gene
Purpose To investigate the feasibility of using kV flat panel detector on linac for consistency evaluations of kV x‐ray generator performance. Methods An in‐house designed aluminum (Al) array phantom with six 9 × 9 cm 2 square regions having various thickness was proposed and used in this study. Through XML script‐driven image acquisition, kV images with various acquisition settings were obtained using the kV flat panel detector. Utilizing pre‐established baseline curves, the consistency of x‐ray tube output characteristics, including tube voltage accuracy, exposure accuracy and exposure linearity was assessed through image quality assessment metrics including ROI mean intensity, ROI standard deviation ( SD ), and noise power spectrums ( NPS ). The robustness of this method was tested on two linacs for a 3‐month period. Results With the proposed method, tube voltage accuracy can be verified through conscience check with a 2% tolerance and 2 kV p intervals for forty different kV p settings. The exposure accuracy can be tested with a 4% consistency tolerance for three mA s settings over forty kV p settings. The exposure linearity tested with 3 mA s settings achieved a coefficient of variation ( CV ) of 0.1. Conclusion We proposed a novel approach that uses the kV flat panel detector available on linac for x‐ray generator test. This approach eliminates the inefficiencies and variability associated with using third‐party QA detectors while enabling an automated process.