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Poster — Wed Eve—37: Phantom Study Comparing Image Quality of Slow‐CT and Average CT Dataset from 4DCT Radiotherapy Planning Acquisitions
Author(s) -
Basran PS,
Karotki A
Publication year - 2009
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 - 10.1118/1.3244141
Subject(s) - imaging phantom , contouring , image quality , computer science , quality assurance , image resolution , artificial intelligence , nuclear medicine , radiation treatment planning , image registration , computer vision , medicine , radiation therapy , image (mathematics) , radiology , computer graphics (images) , external quality assessment , pathology
The purpose of this work was to compare slow‐CT ( CT SLOW ) and average CT ( CT AVE ) datasets with free‐breathing helical CT ( CT HEL ) for contouring of organs at risk (OAR) and radiation treatment planning in patients receiving stereotactic body radiation therapy in lung. A quantitative examination of image quality parameters obtained from 4DCT‐derived datasets was performed using a mobile image quality phantom. The rigid phantom was translated in the superior‐inferior and anterior‐posterior directions through the CT scanning plane. Measurements of noise, low and high‐contrast resolution, spatial linearity, sensitometry, and observation of image artifacts resulting from phantom motion were recorded. In addition to these measurements, we computed the mean CT image ( CT N ) by increasing the number of breathing phases in the average CT calculation, and compared those image quality parameters with CT SLOW , CT AVEand CT HEL . While the image quality parameters were statistically the same in the phantom study, CT AVEdatasets had fewer image artifacts than the CT SLOWdatasets. The image quality of the CT AVEdatasets improved greatly when the number of datasets used to generate the CTN was larger than the maximum permissible bins on the 4DCT reconstruction software (10 phases). CT SLOWor CT AVEdatasets may be used in place of CT HELfor OAR contouring and potentially dose calculations, without significant compromise in image quality. This work demonstrates that when 4DCT is available, it may not be necessary to acquire a separate CT HELscan for OAR contouring.