Four-dimensional computed tomography (4D CT) is a dynamic volume imaging system of moving organs with an image quality comparable to that of conventional CT. 4D CT will be realized by several technical breakthroughs for dynamic cone-beam CT: (1) a large-area two-dimensional (2D) detector; (2) high-speed data transfer system; (3) reconstruction algorithms; (4) ultra-high-speed reconstruction com...

In Image-Guided RadioTherapy (IGRT) of lung tumors, patients undergo a 4D CT, on the basis of which their treatment is planned. It is implicitely assumed that their breathing motion will not change much throughout the treatment, and remain close to what it was during the 4D CT acquisition. During the treatment, several cone beam CT acquisitions are performed, and used to re-position the patient...

The purpose of the present work was to describe the development and validation of a series of tests to assess the quality of four-dimensional (4D) computed-tomography (CT) imaging as it is applied to radiation treatment planning. Using a commercial respiratory motion phantom and a programmable moving platform with a CT phantom, we acquired 4D CT datasets on two commercial multislice helical CT ...

Cardiac and respiratory movements pose significant challenges to image quality and quantitative accuracy in PET imaging. Cardiac and/or respiratory gating attempt to address this issue, but instead lead to enhanced noise levels. Direct four-dimensional (4D) PET image reconstruction incorporating motion compensation has the potential to minimize noise amplification while removing considerable mo...

PURPOSE Reconstruction of the beating heart in 3D + time in the catheter laboratory using only the available C-arm system would improve diagnosis, guidance, device sizing, and outcome control for intracardiac interventions, e.g., electrophysiology, valvular disease treatment, structural or congenital heart disease. To obtain such a reconstruction, the patient's electrocardiogram (ECG) must be r...

In this article, the authors review novel techniques in the emerging field of spatiotemporal four-dimensional (4D) positron emission tomography (PET) image reconstruction. The conventional approach to dynamic PET imaging, involving independent reconstruction of individual PET frames, can suffer from limited temporal resolution, high noise (especially when higher frame sampling is introduced to ...

Three-dimensional sonography (3D US) provides completely new modalities of sonographic scanning including coronar section imaging, three-dimensional reconstruction, volumetric calculations and angio-mode. Improved visualization rate, depiction of spatial relationship, "sculpture like" plastic imaging and volume measurement are the main benefits of new technology. Acceleration in scanning and re...

Conventionally, the inverse problem of gated cardiac SPECT is solved by reconstructing the images frame-by-frame, ignoring the inter-frame correlation along the time dimension. To compensate for the non-uniform attenuation for quantitative cardiac imaging, iterative image reconstruction has been a choice which could utilize an a priori constraint on the inter-frame correlation for a penalized m...

In the radiation therapy of lung cancer, a free-breathing 3D-CT image is usually acquired in the treatment day for image-guided patient setup, by registering with the free-breathing 3D-CT image acquired in the planning day. In this way, the optimal dose plan computed in the planning day can be transferred onto the treatment day for cancer radiotherapy. However, patient setup based on the simple...

INSERM UMR1101, LaTIM, Brest, France Respiratory motion in PET/MR imaging leads to reduced quantitative and qualitative image accuracy. Correction methodologies include the use of respiratory synchronized gated frames which lead to low signal to noise ratio (SNR) given that each frame contains only part of the count available throughout an average PET acquisition. In this work, 4D MRI extracted...