The count rate performance of the single LSO crystal layer high-resolution research tomograph (HRRT-S) PET scanner is limited by the processing speed of its electronics. Therefore, the feasibility of using an in-field-of-view (in-FOV) shield to improve the noise equivalent count rates (NECR) for small animal brain studies was investigated. The in-FOV shield consists of a lead tube of 12 cm leng...

Our expert system aims at the optimum and fast plan making for shield-tunneling works. It is an expert system of applied design problems that integrates such advanced technologies as relational databases , AI, and computer-aided design (CAD). This expert system is able to design and draw a suitable shield machine with an automatic output of design calculations and also specify an optimum contro...

PURPOSE To study the impact on radiation exposure to staff through the use of an original perineal shield during low-dose-rate prostate brachytherapy. MATERIAL AND METHODS We designed a 1 mm thick stainless steel shield that duplicates and is able to slide directly over a standard commercialized prostate brachytherapy grid. We then analyzed the post-procedure exposure in 15 consecutive patien...

the cancer of oral cavity is related to lesions of mucous membrane of tongue and gum that can be treated with radiation therapy. a lateral photon field can be used to treat this kind of tumor, which has a side‑effect on normal tissue in the opposite side of the oral cavity. in this study the dosimetric effect of the various shields in oral cavity is evaluated. in this study, a special phantom s...

Laffer curve indicates relationship between tax rate and tax income. The aim of this paper is estimating of laffer curve in Iranian economy. To do so, we have used threshold regression method. Empirical results indicate that since the tax rate is low (the threshold value is less than 0.0848) in two-regime model, tax rate and tax income have a significant positive relationship, but when the tax ...

Abstract In this paper, Markov chain and dynamic programming were used to represent a suitable pattern for tax relief and tax evasion decrease based on tax earnings in Iran from 2005 to 2009. Results, by applying this model, showed that tax evasion were 6714 billion Rials**. With 4% relief to tax payers and by calculating present value of the received tax, it was reduced to 3108 billion Rials. ...

normal 0 false false false en-us x-none fa introduction: in radiation therapy centers across iran, protection of normal tissues is usually accomplished by either cerrobend or lead block shielding. in this study, the influence of these two shielding methods on central axis dose distribution of photon beam a cobalt unit was investigated in clinical conditions. materials and methods: all measureme...

the taxpayers’ rights must be considered the most important portion of tax laws by tax organization subject to all broad powers and authorities; the thing that has been widely noted in our modern world taking the human and citizenship rights into special consideration by taxation system of developed countries. they also applied various methods to illustrate and execute them in their tax laws. i...