Lone Hoffmann

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INTRODUCTION A new algorithm that uses a grid-based technique to solve the linear Boltzmann transport equation (LBTE) has been developed to improve the accuracy and speed of external photon beam treatment planning calculations. The aim of this study was to test the accuracy of this algorithm in both heterogeneous and homogeneous media. MATERIAL AND(More)
BACKGROUND The survival rates for patients with non-small cell lung cancer (NSCLC) may be improved by dose escalation; however, margin reduction may be required in order to keep the toxicity at an acceptable level. In this study we have investigated the dosimetric impact of tumor motion and anatomical changes during intensity-modulated radiotherapy (IMRT)(More)
PURPOSE Volumetric modulated arc therapy (VMAT) includes features such as a variable dose rate and gantry speed in addition to the beam modulation achieved with multileaf collimator (MLC) motion patterns employed in intensity modulated radiotherapy. Three tests have previously been proposed for the evaluation of the performance of VMAT delivery. In order to(More)
INTRODUCTION The objective of this study was to examine the accuracy of the Anisotropic Analytical Algorithm (AAA). A variety of different field configurations in homogeneous and in inhomogeneous media (lung geometry) was tested for the AAA algorithm. It was also tested against the present Pencil Beam Convolution (PBC) algorithm. MATERIALS AND METHODS Two(More)
PURPOSE To develop a method that allows a commercial treatment planning system (TPS) to perform accurate dose reconstruction for rigidly moving targets and to validate the method in phantom measurements for a range of treatments including intensity modulated radiation therapy (IMRT), volumetric arc therapy (VMAT), and dynamic multileaf collimator (DMLC)(More)
BACKGROUND AND PURPOSE Changes in lung density due to atelectasis, pleural effusion and pneumonia/pneumonitis are observed in lung cancer patients. These changes may be an indication for adaptive radiotherapy in order to maintain target coverage and avoid increased risk of normal tissue complications. MATERIAL AND METHODS CBCT scans of 163 patients were(More)
BACKGROUND AND PURPOSE Advanced lung cancer patients experience anatomical changes during radiotherapy. Uncorrected, these may lead to lower tumor dose, but can be corrected for by adaptive radiotherapy (ART). MATERIAL AND METHODS Anatomical changes in 233 patients were monitored online on cone-beam CT-scans used for daily soft-tissue matching. If(More)
BACKGROUND Patients with non-small cell lung cancer (NSCLC) have poor prognosis partly because of high local failure rates. Escalating the dose to the tumour may decrease the local failure rates and thereby, improve overall survival, but the risk of complications will limit the possibility to dose-escalate a broad range of patients. Escalating only(More)
BACKGROUND AND PURPOSE Low contrast in the cone-beam computed tomography (CBCT) scans hampers fast online evaluation of interfractional changes in the lymph node position on a daily basis. In this study we have investigated whether high-contrast anatomical landmarks in the vicinity of the nodes may be used as surrogates for the lymph node positions. (More)
PURPOSE/OBJECTIVE Daily Cone-beam computed tomography (CBCT) in room imaging is used to determine tumour shrinkage during a full radiotherapy (RT) course. In addition, relative interfractional tumour and lymph node motion is determined for each RT fraction. MATERIAL AND METHODS From November 2009 to March 2010, 20 consecutive lung cancer patients (14(More)