Rongping Zeng

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Respiratory motion remains a significant source of errors in treatment planning for the thorax and upper abdomen. Recently, we proposed a method to estimate two-dimensional (2-D) object motion from a sequence of slowly rotating X-ray projection views, which we called deformation from orbiting views (DOVs). In this method, we model the motion as a time(More)
Convergent Algorithms for Statistical Image Reconstruction in Emission Tomography by Sangtae Ahn Chair: Jeffrey A. Fessler Emission computed tomography (ECT), including positron emission tomography (PET) and single photon emission computed tomography (SPECT), is a medical imaging technique that provides functional information about physiological processes.(More)
A number of interrelated factors can affect the precision and accuracy of lung nodule size estimation. To quantify the effect of these factors, we have been conducting phantom CT studies using an anthropomorphic thoracic phantom containing a vasculature insert to which synthetic nodules were inserted or attached. Ten repeat scans were acquired on different(More)
Understanding the movement of tumors caused by respiratory motion is very important for conformal radiatherapy. However, respiratory motion is very difficult to study by conventional x-ray CT imaging since object motion causes inconsistent projection views, leading to artifacts in reconstructed images. We propose to estimate the parameters of a nonrigid,(More)
Current four-dimensional (4D) computed tomography (CT) imaging techniques using multislice CT scanners require retrospective sorting of the reconstructed two-dimensional (2D) CT images. Most existing sorting methods depend on externally monitored breathing signals recorded by extra instruments. External signals may not always accurately capture the(More)
RATIONALE AND OBJECTIVES The aim of this study was to quantify the effect of overlapping reconstruction on the precision and accuracy of lung nodule volume estimates in a phantom computed tomographic (CT) study. MATERIALS AND METHODS An anthropomorphic phantom was used with a vasculature insert on which synthetic lung nodules were attached. Repeated scans(More)
PURPOSE Iterative reconstruction (IR) algorithms have the potential to reduce radiation dose in CT diagnostic imaging. As these algorithms become available on the market, a standardizable method of quantifying the dose reduction that a particular IR method can achieve would be valuable. Such a method would assist manufacturers in making promotional claims(More)
The purpose of this work was to estimate bias in measuring the size of spherical and non-spherical lesions by radiologists using three sizing techniques under a variety of simulated lesion and reconstruction slice thickness conditions. We designed a reader study in which six radiologists estimated the size of 10 synthetic nodules of various sizes, shapes(More)
As radiotherapy has become increasingly conformal, geometric uncertainties caused by breathing and organ motion have become an important issue. In this work, a nonrigid motion estimation method, which can estimate the motion history of the studied organs, is introduced. This motion information may increase the accuracy of the dose calculation in treatment(More)
RATIONALE AND OBJECTIVES To estimate and statistically compare the bias and variance of radiologists measuring the size of spherical and complex synthetic nodules. MATERIALS AND METHODS This study did not require the institutional review board approval. Six radiologists estimated the size of 10 synthetic nodules embedded within an anthropomorphic thorax(More)