To report on a novel technique for providing artifact-free quantitative four-dimensional computed tomography (4DCT) image datasets for breathing motion modeling. Commercial clinical 4DCT methods have difficulty managing irregular breathing. The resulting images contain motion-induced artifacts that can distort structures and inaccurately characterize breathing motion. We have developed a novel ...

Motion artifacts appear in four-dimensional computed tomography (4DCT) images because of suboptimal acquisition parameters or patient breathing irregularities. Frequency of motion artifacts is high and they may introduce errors in radiation therapy treatment planning. Motion artifact detection can be useful for image quality assessment and 4D reconstruction improvement but manual detection in m...

BACKGROUND To analyze the respiratory-induced motion of each liver segment using helical computed tomography (helical CT) and 4-dimensional computed tomography (4DCT), and to establish the individual segment expansion margin of internal target volume (ITV) to facilitate target delineation of tumors in different liver segments. METHODS Twenty patients who received radiotherapy with CT-simulati...

PURPOSE To assess the effect of additional magnetic resonance imaging (MRI) alongside the planning computed tomography (CT) scan on target volume delineation in pancreatic cancer patients. MATERIAL AND METHODS Eight observers (radiation oncologists) from six institutions delineated the gross tumor volume (GTV) on 3DCT, and internal GTV (iGTV) on 4DCT of four pancreatic cancer patients, while ...

BACKGROUND Cyclic recruitment and de-recruitment of atelectasis (c-R/D) is a contributor to ventilator-induced lung injury (VILI). Bedside detection of this dynamic process could improve ventilator management. This study investigated the potential of automated lung sound analysis to detect c-R/D as compared to four-dimensional computed tomography (4DCT). METHODS In ten piglets (25 ± 2 kg), ac...

PURPOSE The purpose of this study was to compare the positional and volumetric differences of internal target volumes defined on three-dimensional computed tomography (3DCT), four-dimensional CT (4DCT), and cone-beam CT (CBCT) images of non-small-cell lung cancer (NSCLC). MATERIALS AND METHODS Thirty-one patients with NSCLC sequentially underwent 3DCT and 4DCT simulation scans of the thorax d...

BACKGROUND Respiration-gated radiotherapy can permit the irradiation of smaller target volumes. 4DCT scans performed for routine treatment were retrospectively analyzed to establish the benefits of gating in stage III non-small cell lung cancer (NSCLC). MATERIALS AND METHODS Gross tumor volumes (GTVs) were contoured in all 10 respiratory phases of a 4DCT scan in 15 patients with stage III NSC...

PURPOSE A prototype in-house program was developed to assist deriving image guidance shifts clinically using our 4DCT method for lung SBRT. METHODS Our in-house prototype program was implemented in MATLAB. The 4D DICOM CT dataset of interest is imported by the program from AW and subsequently accepts input from the user regarding the desired relative IGRT shifts. The DICOM header information ...

PURPOSE Deformable image registration (DIR) is necessary for accurate dose accumulation between multiple radiotherapy image sets. DIR algorithms can suffer from inverse and transitivity inconsistencies. When using deformation vector fields (DVFs) that exhibit inverse-inconsistency and are nontransitive, dose accumulation on a given image set via different image pathways will lead to different a...

The purpose of this study is to assess the difference between 4D liver dose calculations versus standard 3D treatment planning and to investigate the dosimetric gain of gating on radiation dose to normal tissue. 4DCT scans are collected for 25 patients with hepatic tumors treated by proton radiotherapy. The 4D treatment planning process explicitly takes into account respiratory motion of abdomi...