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PURPOSE To provide an analytical description of the effect of random and systematic geometrical deviations on the target dose in radiotherapy and to derive margin rules. METHODS AND MATERIALS The cumulative dose distribution delivered to the clinical target volume (CTV) is expressed analytically. Geometrical deviations are separated into treatment(More)
A cone beam computed tomography (CBCT) scanner integrated with a linear accelerator is a powerful tool for image guided radiotherapy. Respiratory motion, however, induces artifacts in CBCT, while the respiratory correlated procedures, developed to reduce motion artifacts in axial and helical CT are not suitable for such CBCT scanners. We have developed an(More)
PURPOSE To determine, in three-dimensions, the difference between prostate delineation in magnetic resonance (MR) and computer tomography (CT) images for radiotherapy treatment planning. PATIENTS AND METHODS Three radiation oncologists, considered experts in the field, outlined the prostate without seminal vesicles both on CT, and axial, coronal, and(More)
BACKGROUND AND PURPOSE Conebeam-CT (CBCT) guidance is often used for setup verification of lung cancer patients treated with radiotherapy. The purpose of this study was to quantify intra-thoracic anatomical changes (ITACs) during the radiotherapy treatment and to hand over a decision support system to guide the radiation therapy technologist and radiation(More)
PURPOSE To investigate the applicability of 3-dimensional (3D) surface imaging for image guidance in deep-inspiration breath-hold radiation therapy (DIBH-RT) for patients with left-sided breast cancer. For this purpose, setup data based on captured 3D surfaces was compared with setup data based on cone beam computed tomography (CBCT). METHODS AND(More)
PURPOSE To evaluate the first clinical results of an off-line adaptive radiotherapy (ART) protocol for prostate cancer using kilovoltage cone-beam computed tomography (CBCT) in combination with a diet and mild laxatives. METHODS AND MATERIALS Twenty-three patients began treatment with a planning target volume (PTV) margin of 10 mm. The CBCT scans acquired(More)
PURPOSE Kilovoltage cone-beam computed tomography (CBCT) has been developed to provide accurate soft-tissue and bony setup information. We evaluated clinical CBCT setup data and compared CBCT measurements with electronic portal imaging device (EPID) images for lung cancer patients. METHODS AND MATERIALS The setup error for CBCT scans at the treatment unit(More)
In this review of current clinical practice of set-up error verification by means of portal imaging, we firstly define the various types of set-up errors using a consistent nomenclature. The different causes of set-up errors are then summarized. Next, the results of a large number of studies regarding patient set-up verification are presented for treatments(More)
PURPOSE To quantify in three dimensions the geometric uncertainties of bladder irradiation (i.e., uncertainties in target delineation, organ motion, and patient setup). METHODS AND MATERIALS Pelvic CT images were obtained for 10 male bladder cancer patients. Apart from the initial planning CT scan, three follow-up scans were made for each of the patients.(More)
A generic method for three-dimensional (3-D) evaluation of target volume delineation in multiple imaging modalities is presented. The evaluation includes geometrical and statistical methods to estimate observer differences and variability in defining the Gross Tumor Volume (GTV) in relation to the diagnostic CT and MRI modalities. The geometrical method is(More)