Objective: To investigate the potential dosimetric benefits of four-dimensional computed tomography (4DCT) compared to three-dimensional CT (3DCT) in the planning of radiotherapy for external-beam partial breast irradiation (EB-PBI). Methods: Three-DCT and 4DCT scan sets were acquired for 20 patients who underwent EB-PBI. For each patient a conventional 3D conformal plan (3D-CRT) was generated ...

BACKGROUND The aim of this study was to compare the geometric differences in gross tumor volume (GTV) and surgical clips propagated by rigid image registration (RIR) and deformable image registration (DIR) using a four-dimensional computed tomography (4DCT) image data set for patients treated with boost irradiation or accelerated partial breast irradiation after breast-conserving surgery (BCS)....

BACKGROUND To explore the interobserver variability in the delineation of the tumour bed using seroma and surgical clips based on the four-dimensional computed tomography (4DCT) scan for external-beam partial breast irradiation (EB-PBI) during free breathing. METHODS Patients with a seroma clarity score (SCS) 3 ~ 5 and ≥5 surgical clips in the lumpectomy cavity after breast-conserving surgery...

Lung function depends on the expansion and contraction of lung tissue during the respiratory cycle. The measurement of regional pulmonary function is of great interest and importance since many lung diseases can cause changes in biomechanical or material properties. It is also significant to study the radiation-induced changes in pulmonary function following radiation therapy. In this thesis, w...

PURPOSE To investigate the correlation of gross tumor volume (GTV) motion with the structure of interest (SOI) motion and volume variation for middle and distal esophageal cancers using four-dimensional computed tomography (4DCT). PATIENTS AND METHODS Thirty-three patients with middle or distal esophageal carcinoma underwent 4DCT simulation scan during free breathing. All image sets were regi...

BACKGROUND To investigate the interfraction displacement and volume variation of primary thoracic esophagus carcinoma with enhanced four-dimensional computed tomography (4DCT) scanning during fractionated radiotherapy. METHODS 4DCT data sets were acquired at the time of treatment simulation and every ten fraction for each of 32 patients throughout treatment. Scans were registered to baseline ...

BACKGROUND AND PURPOSE To investigate the definition of planning target volumes (PTVs) based on four-dimensional computed tomography (4DCT) compared with conventional PTV definition and PTV definition using asymmetrical margins for thoracic primary esophageal cancer. MATERIALS AND METHODS Forty-three patients with esophageal cancer underwent 3DCT and 4DCT simulation scans during free breathin...

We present a biomechanical model based four-dimensional computed tomography (4DCT) simulation method for examining the patient lung deformation induced by respiratory motion, given only one CT scan as an input. First, we model the lung stress-strain behavior using a sophisticated hyperelastic model, and solve the lung deformation problem through finite element (FE) analysis. We introduce robust...

Treatment planning for patients undergoing radiation therapy is often performed based on four-dimensional computed tomography (4DCT) when respiratory motion is present, as in lung cancer patients. 4DCT is used to define the internal target volume (ITV) that, ideally, incorporates all potential locations of the tumour. In this work, we use the locations of gold fiducial markers implanted in lung...