the aim of this study was to investigate the effect of tillage methods to obtain suitable seedbed for monogerm seed. therefore, a split plot experiment based on a randomized complete block design (rcbd) with three replicatians was conducted at darab station of fars province. the main plot was seedbed prepration at two levels including fall and spring season. subplot included 1) moldboard plow a...

Background: Accurate small radiation field dosimetry is essential in modern radiotherapy techniques such as stereotactic radiosurgery (SRS) and intensity modulated radiotherapy (IMRT). Precise measurement of dosimetric parameters such as beam profile, percentage depth doses and output factor of these beams are complicated due to the electron disequilibrium and the steep dose gradients. In the p...

background: monte carlo determination of tg-43 brachytherapy dosimetry parameters and dose distribution calculation for 131cs source model cs-1 are presented in this study. materials and methods: the dose distribution was calculated around the 131cs model cs-1 located in the center of 30 cm ×30 cm ×30 cm water, and soft tissue phantoms cube using mcnp code by monte carlo method. the percentage ...

background: dose calculation algorithms play a very important role in predicting the explicit dose distribution. we evaluated the percent depth dose (pdd), lateral depth dose profile, and surface dose volume histogram in inhomogeneous media using calculation algorithms and inhomogeneity correction methods. materials and methods: the homogeneous and inhomogeneous virtual slab phantoms used in th...

In this experimental work, Manganese oxide (MnO2), Zinc oxide (ZnO), Iron oxide (Fe2O3) and Magnesium chloride (MgCl2) were used as activating flux to investigate the effects for SS 304 in tungsten inert gas (TIG) welding. Ultimate tensile strength, percentage elongation, Penetration depth and width were studied of material SS 304. The experimental results indicated that the MnO2 and Fe2O3 flux...

Small fields smaller than 4 × 4 cm2 are used in stereotactic and conformal treatments where heterogeneity is normally present. Since dose calculation accuracy in both small fields and heterogeneity often involves more discrepancy, algorithms used by treatment planning systems (TPS) should be evaluated for achieving better treatment results. This report aims at evaluating accuracy of four model-...

Background: Monte Carlo determination of TG-43 brachytherapy dosimetry parameters and dose distribution calculation for 131Cs source model CS-1 are presented in this study. Materials and Methods: The dose distribution was calculated around the 131Cs Model CS-1 located in the center of 30 cm ×30 cm ×30 cm water, and soft tissue phantoms cube using MCNP code by Monte Carlo method. The percentage ...

Background: Multiple beams are generally used with an increased possibility that the beam axis intersects the treatment table. Treatment tabletops are commonly made of carbon fiber due to its high mechanical strength and rigidity, low specific density, extremely light and low radiation beam attenuation properties. Purpose of this paper is investigated the dose changes in the buildup region and ...

Background: Radiotherapy Treatment Planning requires different dosimetric quantities as input in order to calculate a desired dose distribution. This study has been focused to evaluate the depth dose characteristics of superficial X-rays being used for radiotherapy treatment. Materials and Methods: Computerized 3-D water phantom of multi-data system was used. The measurements were made...