A Method for Optimizing the Parameters of Chest Low-dose CT Scanning

Abstract

The invention relates to a method for optimizing chest low-dose CT scanning parameters, which is characterized in that, using standard CT scanning equipment, the CT images of the simulated human body model are obtained multiple times by setting the scanning parameter gradient, and the objective image quality index and subjective image quality evaluation are obtained index, and establish a corresponding relationship; use the tested CT scanning equipment to obtain the CT image of the simulated human body model, and according to the corresponding relationship, screen out the scanning parameters corresponding to the lowest effective radiation absorbed dose; the optimization method provided by the present invention, Simple, effective, and universal, it can obtain the optimal combination of scanning parameters that meet the diagnostic requirements on any CT scanning equipment, and minimize the absorbed radiation dose of the subject, thus effectively solving the problems in the existing technology. There is a lack of consistency and reliability in the selection of CT screening scan parameters, especially for the optimization of scan parameters for lung nodule screening in high-risk groups of lung cancer.

Description

technical field [0001] The invention relates to the technical field of medical imaging, in particular to a method for optimizing chest low-dose CT scanning parameters. Background technique [0002] Lung cancer is currently the malignant tumor with the largest number of deaths in the world. According to statistics, in 2012, lung cancer accounted for about 25% of the cancer deaths in the United States; lung cancer is currently the malignant tumor with the largest number of deaths in China, and its incidence rate is increasing; The survival rate is only 12-17%, and the 5-year survival rate after surgery for stage I lung cancer can reach more than 60%. Therefore, early diagnosis and treatment of lung cancer is the most important means to improve the survival rate of lung cancer patients. After many clinical trials and experiences, it has been proved that using traditional chest X-rays for lung cancer screening cannot effectively reduce lung cancer mortality, because CT has a sig...

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Problems solved by technology

It is estimated that long-term radiation exposure in LDCT screening may lead to 1 / 2500 subjects' tumor-related mortality. Although the harm is far less than the benefits of screening-reduced mortality, the radiation dose is still an important factor in LDCT screening. There is an important controversy and a point that needs to be improved

[0004] In the prior art, the method of reducing the dose of LDCT is mainly by changing the scanning parameters, including reducing the tube current and tube voltage, and improving the quality of image reconstruction in image post-processing, including the use of improved image post-processing algorithms, such as iterative reconstruction algorithms, etc. ; Experimental studies have confirmed that LDCT with a tube current of 30mAs-50mAs and conventional diagnostic CT with a tube current of 200mAs have good consistency in the screening of pulmonary nodules, but there is no authoritative specification for the selection of scanning parameters at present, and There are differences according to different studies, most of which did not consider the impact of different scanning conditions and reconstruction algorithms on key nodule characteristics, such as size and volume; even the internationally recognized National Comprehensive Cancer Network (NCCN) low In the dose CT lung cancer screening guidelines, it is also recommended that the scanning tube voltage is 100-120KV and the tube current is not greater than 60mAs, but there are no specific image quality requirements, and no specific recommendations are made for the parameters of different equipment; so simply changing the scanning parameters The purpose of reducing the dose can be achieved, but the scan image quality lacks consistency and reliability. For example, Kim et al. found that the LDCT image quality may decrease as the subject's BMI (body mass index) increases; Willemink et al. simulated the human body model Experiments have found that for small pulmonary nodules with a diameter less than or equal to 3mm, after reducing the voltage and current of the scanning tube, the size of the nodules in the CT scan image is systematically underestimated; and Wielpütz et al. found through the simulation of the human body model that the scanning conditions After changing from 120KV and 12mAs to 80KV and 12mAs, the volume measurement error of tiny nodules increases; therefore, for different scanning equipment, it is important for future LDCT technology to obtain image quality that meets the diagnostic requirements under the condition of low radiation dose. research direction

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