Acquisition, preprocessing, and reconstruction of ultralow dose volumetric CT scout for organ‐based CT scan planning. Issue 5 (14th May 2015)

• Record Type: Journal Article
• Authors: Yin, Zhye; Yao, Yangyang; Montillo, Albert; Wu, Mingye; Edic, Peter M.; Kalra, Mannudeep; De Man, Bruno
• Is Part Of: Medical physics. Volume 42:Issue 5(2015)
• Page Start: 2730
• Page End: 2739
• Publication Date: 2015-05-14
• Subjects: biological organs -- computerised tomography -- diagnostic radiography -- image reconstruction -- image segmentation -- medical image processing; Reconstruction -- Segmentation -- Computed tomography -- Computed radiography; Computerised tomographs -- Biological material, e.g. blood, urine; Haemocytometers -- Digital computing or data processing equipment or methods, specially adapted for specific applications -- Image data processing or generation, in general; 3D volumetric scout -- ultralow dose -- organ segmentation and localization -- scan planning; Three dimensional image processing -- Medical image noise -- Image reconstruction -- Computed tomography -- Liver -- Medical image reconstruction -- Radiography; Medical physics -- Periodicals; Medical physics; Geneeskunde; Natuurkunde; Toepassingen; Biophysics; Periodicals; Periodicals; Electronic journals; 610.153
• DOI: 10.1118/1.4921065
• Languages: English
• ISSNs: 0094-2405

Abstract

Abstract : Purpose: Traditionally, 2D radiographic preparatory scan images (scout scans) are used to plan diagnostic CT scans. However, a 3D CT volume with a full 3D organ segmentation map could provide superior information for customized scan planning and other purposes. A practical challenge is to design the volumetric scout acquisition and processing steps to provide good image quality (at least good enough to enable 3D organ segmentation) while delivering a radiation dose similar to that of the conventional 2D scout. Methods: The authors explored various acquisition methods, scan parameters, postprocessing methods, and reconstruction methods through simulation and cadaver data studies to achieve an ultralow dose 3D scout while simultaneously reducing the noise and maintaining the edge strength around the target organ. Results: In a simulation study, the 3D scout with the proposed acquisition, preprocessing, and reconstruction strategy provided a similar level of organ segmentation capability as a traditional 240 mAs diagnostic scan, based on noise and normalized edge strength metrics. At the same time, the proposed approach delivers only 1.25% of the dose of a traditional scan. In a cadaver study, the authors' pictorial‐structures based organ localization algorithm successfully located the major abdominal‐thoracic organs from the ultralow dose 3D scout obtained with the proposed strategy. Conclusions: The authors demonstrated that images with a similar degree of segmentation capability (interpretability) as conventional dose CT scans can be achieved with an ultralow dose 3D scout acquisition and suitable postprocessing. Furthermore, the authors applied these techniques to real cadaver CT scans with a CTDI dose level of less than 0.1 mGy and successfully generated a 3D organ localization map.