ABSTRACT
Objective To study the impact of respiratory frequency and amplitude of patients with the thoracic or abdomen tumor on 4DCT' s reconstructed image.Methods 75 thoracic or abdomen tumor patients who performed a scanning with belly belt-type respiratory gating on 4DCT between November 2012 to March 2013 in our hospital were retrieved.Reviewed their respiratory frequency,amplitude and fault distance of 4DCT' s reconstructed image and analyzed the correlation fault distance of the reconstructed image.The correlation analysis was used by bivariate Spearman method.Results Among these reconstructed images,fault distance more than 6 mm could be seen in 11 cases,fault distance ranging from 3 mm to 6 mm could be found in 46 cases,and distance less than 3 mm could be detected in 18 case.Respiratory frequency correlated significantly with the amplitude (rs =0.369,P =0.000);the respiratory rate had a tight association with the fault distance of the reconstructed image (r,=0.273,P=0.018);and respiratory amplitude was associated obviously with the fault distance of the reconstructed image (r,=0.696,P=0.000).Conclusions Both 4DCT reconstructed image and respiratory amplitude are significantly correlated to the continuity of the respiratory frequency.The smaller the respiratory frequence and amplitude change are,the better continuity will be.