according to high costs of phase shifters in antenna arrays, new methods for beam steering without phase shifter were introduced. frequency diverse array (fda) concept is another approach to beam steering problem. in this structure, the subsequent antenna elements are fed with stepped discrete frequencies causing continuous scanning of space in time. so a range-angle dependent scanning is made ...

A scanning beam profile monitor is described that was developed for use along the Stanford two-mile linear accelerator. The maximum beam loss due to scattering caused by this monitor can be made to be a small fraction of that which would be caused by a Cerenkov radiator or scintillating screen. (To be submitted to the Review of Scientific Instruments) * Work supported by the U. S. Atomic Energy...

A 15by 15-cm supersonic wind tunnel application of a one-dimensional laser beam scanning approach to shock sensing is presented. The measurement system design allowed easy switching between a focused beam and a laser sheet mode for comparison purposes. The scanning results were compared to images from the tunnel Schlieren imaging system. The tests revealed detectable changes in the laser beam i...

The optimal design of a radiotherapy treatment depends on the collection of directions from which radiation is focused on the patient. These directions are manually selected by a physician and are typically based on the physician’s previous experiences. Once the angles are chosen, there are numerous optimization models that decide a fluency pattern (exposure times) that best treats a patient. S...

OBJECTIVE This study was designed to investigate treatment efficacy and side effects of concomitant Aisu® (docetaxel) with three-dimensional conformal external beam radiotherapy for the treatment of inoperable patients with esophageal cancer. METHODS Inoperable patients were treated with three-dimensional conformal external beam radiotherapy (5/week, 2 GY/day, and total dose 60GY) plus doceta...

ntroduction:  monte  carlo  simulation  is  the  most  accurate  method  of  simulating  radiation  transport  and  predicting doses at different points of interest in radiotherapy. a great advantage of the monte carlo method  compared  to  the  deterministic  methods  is  the  ability  to  deal  accurately  with  any  complex  geometry.  its  disadvantage is the extremely long computing time r...

At National Institute of Radiological Sciences (NIRS), more than 6500 patients have been successfully treated by carbon-ion beams since 1994. The successful results of treatments have led us to construct a new treatment facility equipped with three-dimensional pencil beam scanning irradiation system. The commissioning of NIRS fast scanning system installed into the new facility was started in S...

BACKGROUND A new device, Intrabeam, is available for intraoperative radiotherapy. We have prospectively examined its feasibility and tolerability in delivering adjuvant breast cancer treatment. METHODS Thirty-five patients undergoing breast-conserving surgery received targeted tumour bed irradiation consisting of 5 Gy (at 10 mm) in a single fraction. This single intraoperative treatment was u...

 Introduction: Monte Carlo method is often applied in radiation therapy as utilized in all the branches of science. An important requirement for successful radiotherapy is carefully examine the dose distribution specifications and decrease the difference between these features with experience to an acceptable level. In this study, the characteristics of 6, 15 and 20 MeV incident x-rays are prov...

BACKGROUND Adjuvant radiotherapy is common for uterine corpus cancer patients, yet the long-term carcinogenic effects of different types of radiotherapy have not been studied adequately. METHODS Second primary cancer risks were quantified in a cohort of 60,949 individuals surviving > or = 1 year of uterine corpus cancer diagnosed from 1973 to 2003 in Surveillance, Epidemiology and End Results...