a. zeinali

Inclusion of air-filled cavities in the head and neck treatment fields due to electronic disequilibrium may lead to uncertainties in predicting dose distribution by treatment planning systems (TPS). In this study the Full Scatter Convolution Algorithm (FSC) used in TiGRT treatment planning systems was evaluated using a novel 3D film dosimetry method.

9 pieces of EBT2 films were embedded in a rectangular inhomogeneous head and neck phantom. Three approximately small field sizes including sandwiched EBT films which embedded between phantom slabs were exposed with 6 MV X-ray photons. A homemade computer code was developed in MATLAB for the creation of a 3D dose map of irradiated films and calculation of enclosed volumes which were surrounded by isodose lines in films. Then the calculated dose volumes were compared with the same quantities derived from Dose Volume Histogram (DVH) which is available in TPS outputs.

Our results showed significant differences between the results of the film dosimetry and DVH values. The maximum difference of calculated and measured values was observed in volumes surrounded by 95% isodose curves and 3x3cm2 field size (P=0.035) and the minimum difference was observed in volumes surrounded by 95% isodose curves and 5x5cm2 field size (P=0.047).

The results of this study demonstrated overestimated results in volumetric dose calculation of the FSC dose calculation algorithm in the presence of inhomogeneities and the 3x3cm2 field size. Also, these results confirmed that the utilization of an accurate and comprehensive method such as 3D film dosimetry can be useful for TPS verification.

Drug and alcohol use is known as a social harm that inflicts great damage on society. This research aimed to investigate the prevalence rate of drug and alcohol use among students of Urmia University. Present research was a cross-sectional that 450 students from among the students of Azad, State and Payame Noor universities in Urmia city during the 2017-18 academic years were selected through random cluster sampling method. All of them responded to the alcohol, smoking and substance involvement screening test and after removing the incomplete questionnaires, the analysis was performed for 436 questionnaires by using method of Chi-squared test. The findings showed that the prevalence of cigarette, alcohol and drug use was 35/55%, 15/82% and 16/28%, respectively. The prevalence of cigarette and alcohol use in men students significantly was higher than woman students, but the prevalence of drug use there wasn’t significant difference in them. Also, the prevalence of cigarette, alcohol and drug use in students wasn’t significant difference based on age range, educational level and marriage. In addition, the prevalence of cigarette, alcohol and drug use in students of art and urban department significantly was higher than other departments (p<0/05). The results showed that the gender and educational department are effected by common patterns of drug use and put students at risk, therefore the necessity review strategic strategies is apparent by officials and planners.

Educational failure is an important problem of most of the educational centers that needs urgent strategies. This study aimed to analyze the effects of teaching the learning and studying on the educational development of unsuccessful college students.

This experimental study was conducted on 28 college students that were chosen randomly and were divided into two experiment and control groups which were studied with a pre-test and post-test pattern based on the students average in two semesters. The experiment group was thought in 8 one-hour sessions individually، while control group did not receive any. The difference between the final grades of second semester every year was analyzed by SPSS software after exam.

The average grade of the experimental group in pretest was 11. 03 that increased to 14. 14 after educational contract. While the control group average grade was 10. 94 that decreased to 10. 82 after the test. So according to the results، there was a meaningful difference between the average grade of the control and experimental groups. Also the rate of educational failure among the boy students was sufficiently more than girls.

The results of this study show that teaching the learning and studying methods has a positive effect on educational improvement of students and can be an educational model during the training especially for the first term. There was a meaningful difference between the rate of educational failure of girls and boys that need to be studied.

These days critical thinking has been introduced as the main output of education by field experts. They notice teaching of thinking as a principal of learning. This study aimed to examine the association between critical thinking and high school student's educational progress.

This correlational study was conducted on 355 high school students in 2010-2011. California Critical Thinking Willing test was used as data collection tool. Descriptive and analytical tests including t-test and ANOVA were applied for data analysis using SPSS.

Mean and standard deviation of total score was 289.60 ±34.09. The lowest and highest scores were 190 and 398, respectively. Accordingly, the trend of critical thinking and educational achievement has no relationship with sex, major, and degree.

In the study, total score of critical thinking was high. Education of critical thinking between instructor and students required interaction each other and creating an organized frame work for intellectual processes and using relevant skills and positions.