A quantitative evaluation on the image-quality parameters and quality assurance thresholds setting of accelerator on-board imaging system
10.3760/cma.j.issn.1004-4221.2019.12.009
- VernacularTitle: 加速器机载影像系统图像质量量化评价及质量保证阈值设定研究
- Author:
Jinyan HU
1
;
Yuntong PEI
;
Yangguang MA
;
Haiyang WANG
;
Lele LIU
;
Yuexin GUO
Author Information
1. Department of Radiation Oncology, First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
- Publication Type:Journal Article
- Keywords:
On-board imaging;
Image quality;
Quantitative evaluation;
Threshold setting
- From:
Chinese Journal of Radiation Oncology
2019;28(12):919-923
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To achieve quantitative analysis of image quality parameters and establish warning and action thresholds for the on-board imaging (OBI) system of linear accelerator.
Methods:The Catphan604 phantom was repeatedly scanned in the Full-Fan and Half-Fan CBCT scanning modes on a Varian EDGE linear accelerator, and the software based on Python language development in-house was utilized to analyze image quality parameters, such as CT number linearity, geometric consistency, slice thickness, spatial resolution, uniformity and low-contrast resolution. The quantitative analysis results of each image quality parameter obtained from 16 times of scanning within 16 months were normalized to the mean and the standard deviations were recorded. A run chart analysis was created to determine the warnings and action thresholds.
Results:The software built in-house can quantitatively analyze the image parameters of the two scanning modes of OBI system. The low-contrast resolution of Half-Fan was better than that of Full-Fan, whereas the spatial resolution of Full-Fan was superior to that of Half-Fan. One standard deviation (1σ) was set as the warning threshold and 2 standard deviations (2σ) as the action threshold, respectively. The tolerance level of Half-Fan was smaller than that of Full-Fan.
Conclusion:Self-developed software enables quantitative analysis of accelerator image quality parameters, establishes warning and action tolerance of quality assurance and provides guidance for image quality assurance under image-guided radiotherapy specification.
