Background: In this study, a comparison between various types of radiotherapy treatment for parotid gland cancer was performed to achieve the optimal treatment technique.Methods: Treatment planning and countering performed with TiGRT software for 15 patents with parotid gland cancer. Six techniques were performed and compared. Finally, by comparing the dose volume histograms (DVH), average dose received by each organ was determined and the best method was introduced. Techniques were as: 1. an ipsilateral wedge pair technique using 6 MV photons; 2. a 3-field anteroposterior (AP) (wedged) posteroanterior (PA) (wedged) and lateral portal technique using 6 MV photons; 3. a mixed beam technique using 6 MV photons and 12 MeV electrons (1: 4 weighting); 4. a mixed beam technique using 6 MV photons and 15 MeV electrons (1: 4 weighting); 5: four 6 MV photon beams with different gantry angles; and 6. similar to fifth technique with an additional small ring around the tumor tissue. Findings: Intensity-modulated arc therapy (IMRT) techniques five and six delivered maximum dose to the target and minimum dose to organ at risks (OAR). Among 3-D conformal radiotherapy techniques (CRT), technique number two delivered more amount of dose to the target than techniques number three and four. The dose delivered to the contrary parotid gland was negligible for Intensity-modulated arc therapy techniques.Conclusion: Intensity-modulated arc therapy techniques are most appropriate methods for treating cancer of the parotid gland and the sixth technique delivered better dose distribution in the tumor and healthy tissues. Second D conformal radiotherapy technique delivered higher average dose to the target.

Background: Intensity-Modulated Radiation Therapy (IMRT) is one of the best methods in the treatment of optic nerve sheath meningioma (ONSM) with tumor growth control and visual stabilization. In this study, various IMRT techniques were evaluated from the point of view of dose fall-off beyond the target boundaries to achieve the optimal technique. Methods: The optimization of 3 IMRT techniques was performed using 3, 5, and 7 fields with 6 MV photons in 15 patients with ONSM using Prowess Panther treatment planning system. To evaluate treatment plans, in addition to data extracted from dose-volume histogram (DVH) and evaluation of target coverage indices, differential and cumulative dose gradient indices (DGIs) were calculated and compared between the three techniques. Findings: The maximum and the mean dose received by the tumor increased with increasing number of IMRT fields. The uniformity (UI) and homogeneity (HI) indices were significantly different between the 3-field and 7-field techniques; and the conformity index (CI) was close to ideal value (0. 99) in 7-field technique. Difference of differential dose gradient index (dDGI) was negligible between the three techniques, and only at the 45% isodose level, there was a significant difference between the 5-and 7-field techniques. Cumulative dose gradient index (cDGI) showed smaller values in 7-field technique than the other two techniques. Conclusion: The three IMRT techniques have no considerable statistical difference in dose fall-off rate beyond tumor boundaries; and their choice in the treatment of ONSM depends on the physician's discretion based on the whole patient's conditions.

This paper is devoted to explore the relationship between earthquake Intensity in the epicenter and its magnitude as well as the Intensity attenuation laws of the Iranian earthquakes. For this purpose, available data, reports, seismotectonic and isoseismalmaps, related to 21 destructive earthquakes in a period of 1957 to 1998, were studied.The results show that the Intensity-magnitude relationships and the Intensity attenuation laws are strongly dependent on the site geology that specifies local effects. Therefore, the sites have been classified, according to site geology, into two groups, hard sites and soft sites. The Intensity-magnitude and Intensity attenuation versus the distance from the earthquake sources (surface refaulting of the causative fault (s)) were determined and introduced for each of the two site groups. Finally, the obtained laws were compared with some other laws offered by other researchers.

Faith is the key word and axis of Islam. To attain happiness and salvation in all divine religions is possible only in the light of faith. Since the reality of faith is immaterial such as hope, love and piety and are subjective in nature so it is impossible to give a clear definition of it. Hence in Islamic culture too no clear definition have been proposed.As for other issues such as the synonymy of faith and Islam and their other parts and the relation of faith with action and its Intensity, these were considered by khawarij first as political issues and then were considered as theological issues. Scholars have proposed various views concerning the parts and Intensity of faith and so far no clear view have been posed. This article is an attempt to make clear the relation of faith and Islam, the parts of faith, and to prove its Intensity.