Impact of 4D image quality on the accuracy of target definition.

Delineation accuracy of target shape and position depends on the image quality. This study investigates whether the image quality on standard 4D systems has an influence comparable to the overall delineation uncertainty. A moving lung target was imaged using a dynamic thorax phantom on three different 4D computed tomography (CT) systems and a 4D cone beam CT (CBCT) system using pre-defined clinical scanning protocols.

A dual centre study of setup accuracy for thoracic patients based on cone-beam CT data.

Background And Purpose: To compare setup uncertainties at two different institutions by using identical imaging and analysis techniques for thoracic patients with different fixation equipments.

Methods And Materials: Patient registration results from Cone-Beam CT (CBCT) scans of 174 patients were evaluated (1068 CBCT scans). Patients were fixated using a standard or custom made fixation at Royal Marsden Hospital and Odense University Hospital, respectively.

Influence of dose calculation algorithms on the predicted dose distribution and NTCP values for NSCLC patients.

Purpose: To investigate differences in calculated doses and normal tissue complication probability (NTCP) values between different dose algorithms.

Methods: Six dose algorithms from four different treatment planning systems were investigated: Eclipse AAA, Oncentra MasterPlan Collapsed Cone and Pencil Beam, Pinnacle Collapsed Cone and XiO Multigrid Superposition, and Fast Fourier Transform Convolution. Twenty NSCLC patients treated in the period 2001-2006 at the same accelerator were included and the accelerator used for treatments were modeled in the different systems.