background: length of stay is one of the most important indicators in assessing hospital performance. a shorter stay can reduce the costs per discharge and shift care from inpatient to less expensive post-acute settings. it can lead to a greater readmission rate, better resource management, and more efficient services. objective: this study aimed to identify the factors influencing length of ho...

A time-consuming component of IMRT optimization is the dose computation required in each iteration for the evaluation of the objective function. Accurate superposition/convolution (SC) and Monte Carlo (MC) dose calculations are currently considered too time-consuming for iterative IMRT dose calculation. Thus, fast, but less accurate algorithms such as pencil beam (PB) algorithms are typically u...

This study quantifies the dosimetric accuracy of a commercial treatment planning system as functions of treatment depth, air gap, and range shifter thickness for superficial pencil beam scanning proton therapy treatments. The RayStation 6 pencil beam and Monte Carlo dose engines were each used to calculate the dose distributions for a single treatment plan with varying range shifter air gaps. C...

Sediment rating curve (SRC) is a conventional and a common regression model in estimating suspended sediment load (SSL) of flow discharge. However, in most cases the data log-transformation in SRC models causing a bias which underestimates SSL prediction. In this study, using the daily stream flow and suspended sediment load data from Shalman hydrometric station on Shalmanroud River, Guilan Pro...

Karin Andersson (2018): Metal Artifacts in Computed Tomography – impact of reduction methods on image quality and radiotherapy treatment planning. Örebro Studies in Medicine 172. Degradation of image quality by metal artifacts is a common problem in computed tomography (CT) imaging, which can limit the diagnostic value of a CT examination and also introduce inaccuracies in radiotherapy (RT) tre...

background: medical image interpolation is recently introduced as a helpful tool to obtain further information via initial available images taken by tomography systems. this information may be useful for better diagnosis of possible lesions or better tumor delineation at radiation treatment. to do this, deformable image registration algorithms are mainly utilized to perform image interpolation ...

PURPOSE To investigate effects of metal artifacts on the dose calculation accuracy of three dose calculation algorithms on CT and cone-beam CT images. METHODS A phantom with and without metal objects was scanned using CT simulator and on-board kV CBCT. Conformal 5-field treatment plans with identical physical and dosimetric parameters were created in the Eclipse™ treatment planning system for...

Introduction: Nowadays radiotherapy plays an important role in cancer treatment. Different radiotherapy techniques improvement emphasizes on using of the precise ، appropriate and useful algorithms. one of these techniques are wedged which is used in radiotherapy to compensate missing tissues and create a uniform dose distribution in tissues. The Siemens Artiste linear accelera...