Tumor tracking is an option for intra-fractional motion management in radiotherapy. The VERO gimbal tracking system creates a unique beam geometry and understanding the effect of the gimbal motion in terms of dose distribution is important to assess the dose deviation from the reference conditions. Beam profiles, output factors (OF) and percentage depth doses (PDD) were measured and evaluated t...

contrary to president obama’s stated position in november 2009, it is presumed here that the islamic republic intentionally procrastinates normalization of its foreign policy towards the u.s. this intentional delay is due to mutual mistrust existing between the two states. nonetheless, the islamic republic is determined to avoid further confrontation with the u.s. in this respect, the islamic r...

BACKGROUND Limited data define what constitutes a minimal clinically important difference (MCID) on the EuroQol 5-Dimension (EQ-5D) health status index in persons with multiple sclerosis (PwMS). We sought to estimate the MCID for the EQ-5D health index in North American PwMS. METHODS PwMS completing the Patient Determined Disease Steps (PDDS) scale, 12-Item Multiple Sclerosis Walking Scale (M...

PURPOSE Exit 2D detectors are widely used in clinics as a tool for pre- treatment field verification. It is desired to have accurate modeling of the detector dose for each IMRT plan with patient geometry for in-vivo delivery verification. We propose a novel hybrid of model and measurement based methods to estimate the detector dose using the information from TPS and plan/verification CT. METH...

The purpose of this study was to empirically characterize and validate a kilovoltage (kV) X-ray beam source model of a superficial X-ray unit for relative dose calculations in water and assess the accuracy of the British Journal of Radiology Supplement 25 (BJR 25) percentage depth dose (PDD) data. We measured central axis PDDs and dose profiles using an Xstrahl 150 X-ray system. We also compare...

This paper presents a method to find the optimum maintenance policy for a component. Random failures and failures due to deterioration are considered. Using Markov processes, the state probabilities are calculated and the optimal value of the mean time to preventive maintenance is determined by maximizing the availability of single component with respect to mean time to minimal preventive maint...

We develop a simple macroeconomic model where the time inconsistency of optimal monetary policy is due to tax distortions. If fiscal policy is exogenously fixed at its optimal level, a Walsh contract (Walsh, 1995) offered to an independent central bank implements the optimal monetary policy. When fiscal policy is determined endogenously, however, this contract is subject to strategic manipulati...