TLD based method to estimate bowtie filter shape in PET/CT

Background: In CT systems, the machine utilizes a bowtie filter to shape the X -ray beam and remove lower energy photons. The shape of this bowtie filter is complicated and its geometry is often not available in detail. These renders the CT dose index [CTDI] to have different values in measurement versus Monte Carlo simulation studies and other analytical calculations especially in dosimetry of internal organs. In existing literature, the bowtie filter shape is extracted by using expensive sensors

Materials and Methods: In the present work, the shape of the bowtie filter of the Biograph 6 PET/CT was derived by using Thermolumenecence dosimeters [TLDs]. Subsequently, to evaluate the accuracy of the body bowtie filter shape as generated by TLDs, Monte Carlo simulation of CT was performed. 16 X-ray sources in various angles were used within the Monte Carlo code [MCNP-4C] to simulate the CT section of the PET -CT Biograph 6 system and to calculate dose

Results: The relative difference between simulated and measured CTDI value for the PET/CT Siemens Biograph 6 at 80, 110 and 130 kVp were 4.2, 2.9 and 2.3%, respectively

Conclusion: In this study, we demonstrate that it is possible to calculate the bowtie filter shape by using an inexpensive TLD method. The results showed that it is possible to determine the shape of the bowtie filter in PET/CT using TLDs with acceptable accuracy?

hybrid ANN-GA model to prediction of bivariate binary responses: application to joint prediction of occurrence of heart block and death in patients with myocardial infarction

Background: In medical studies, when the joint prediction about occurrence of two events should be anticipated, a statistical bivariate model is used. Due to the limitations of usual statistical models, other methods such as Artificial Neural Network [ANN] and hybrid models could be used. In this paper, we propose a hybrid Artificial Neural Network-Genetic Algorithm [ANN-GA] model to prediction the occurrence of heart block and death in myocardial infarction [Ml] patients simultaneously

Methods: For fitting and comparing the models, 263 new patients with definite diagnosis of Ml hospitalized in Cardiology Ward of Hajar Hospital, Shahrekord, Iran, from March, 2014 to March, 2016 were enrolled. Occurrence of heart block and death were employed as bivariate binary outcomes. Bivariate Logistic Regression [BLR], ANN and hybrid ANN-GA models were fitted to data. Prediction accuracy was used to compare the models. The codes were written in Matlab 2013a and Zelig package in R3.2.2

Results: The prediction accuracy of BLR, ANN and hybrid ANN-GA models was obtained 77.7%, 83.69% and 93.85% for the training and 78.48%, 84.81% and 96.2% for the test data, respectively. In both training and test data set, hybrid ANN-GA model had better accuracy

Conclusions: ANN model could be a suitable alternative for modeling and predicting bivariate binary responses when the presuppositions of statistical models are not met in actual data. In addition, usinc optimization methods, such as hybrid ANN-GA model, could improve precision of ANN model

[Electrolyte disorders after coronary artery bypass grafting surgery and its related factors]

Introduction: coronary artery bypass grafting surgery is a common therapeutic intervention in patients with coronary artery disease. This surgery has various complications. Electrolyte disorders are among common important complications among these patients

Objective: purpose of this study was to determine the level of electrolyte disorders and related factors in patients after coronary artery bypass grafting surgery hospitalized in cardiac care units

Methods: in this descriptive cross-sectional study, 288 Coronary Artery By Pass Graft [CABG] patients admitted to educational hospital were selected by gradual sampling. Data were collected by a three part researcher made questionnaire covering demographics, past medical history and levels of sodium and potassium through patients' medical records. Statistical analyses were performed using appropriate tests [chi square test, fisher exact test and logistic regression]

Results: findings showed that 16.7% of patients undergoing coronary artery bypass grafting were hyponatremia, 4.9% hypernatremia, 14.2% hypokalemia and 3.8% hyperkalemia. The results also indicated that there was a significant relationship between the factors such as body mass index, history of drug use, the number of vessels involved, the number of grafts, the length of time connected to mechanical ventilation, duration of artificial heart-lung machine use, aortic clamping time, and amount of intraoperative hypothermia, hemoglobin and hematocrit and postoperative electrolyte disorders [P<0.05]. According to Logistic regression model, these factors were not associated to electrolyte abnormalities

Conclusion: the findings showed that many factors such as individual medical history and condition during surgery can affect electrolyte abnormalities after coronary artery bypass graft. Identifying these factors can be useful in planning for prevention, diagnosis and early treatment of possible complications which in turn may result in promotion of quality care

Experimental and Monte Carlo studies on the response of CR-39 detectors to Am-Be neutron spectrum

The Poly-Allyl Diglycol Carbonate [PADC] detector is of particular interest for development of a fast neutron dosimeter. Fast neutrons interact with the constituents of the CR-39 detector and produce H, C and 0 recoils, as well as [n, a] reaction. These neutron- induced charged particles contribute towards the response of CR-39 detectors. Material and Electrochemical etching was used to enlarge track diameter which was made by low energy recoil protons. Before electrochemical etching, a chemical etching was performed for 1 hour. The responses were also calculated by Monte Carlo simulations, using MCNPX code in different energy bins considering H, C and O recoils. The total registered efficiency and partial contributions of the efficiency, due to interactions with each constituent of CR-39, were calculated. The optimized condition of etchant was obtained to be 6N KOH 15kV.cm[1], and 6 hours etching time. The obtained results show that track efficiency of CR-39 was a function of incident neutron energy. The tracks caused by O and C recoil nuclei were negligible for neutron energies lower than 1 MeV. At neutron energies lower than 1 MeV, only recoil protons would have sufficient energy to leave visible tracks. But, O and C recoils had important contributions in overall response of PADC at neutron energies of few MeV. The efficiency of a CR-39 based dosemeter could be calculated by MCNPX code and the results were in a good agreement with experimental results in energy range of [241]Am - Be bare source and [241]Am-Be was softened with a spherical polyethylene moderator of radius of 20 cm

[Investigation of prevalence of child abuse in addicts referring to the addiction withdrawal clinic]

Child abuse includes; abuse of the body, mental and sexual abuse or misbehavior against children that leads to damage to the child's health and comfort. Therefore, the present study was done in order to determine the prevalence of child abuse in opiate addicts referring to addiction withdrawal centers. The cross sectional study included 300 participations [150 addicts and 150 non-addicts] The addicted group comprised of opiate addicts referring to addiction withdrawal centers of Yazd. The non addicted group was selected randomly from healthy people. Data collection was performed via a standard questionnaire. Data assessment was done via statistical analysis [K S] Collected data in the addicted group showed the following results; about 56 percent were child tormentors, 1- 45.3% males, 10.7% females, 2-18.7% uneducated, 3-46% with divorce history in their family and 4-38% child body abuse. The most prevalent type of the body abuse was slapping [24%], mostly because of bad training [26%]. Collected data in the no addicted group showed the following results; 42% were child tormentors [26% male and 15.3% female] 23.4% with family divorce history, 30.4% were child body abuse and the most prevalent type of body abuse was slapping [22.79%], mostly because of bad training [33.3%] A direct relationship was observed between child abuse and persons addicted to opiates. Factors playing an important role include; illiteracy, divorce history in the family and history of child abuse in childhood period. Therefore, compilation of rules supporting children, establishment of support and parent education centers can be effective to reduce child persecution

[Assessment of academic motivation and its relationship with health-risk behaviors in male students of Yazd university]

University is a position of formal training and learning and students in order to successful in this position should have effective learning. Motivation is key to effective learning. Additional to academic motivation can have the role of prevention in high-risk health behaviors. We examined students motivation in Yazd and communication with academic motivation in high-risk health behavior study. This was a cross-sectional study and the sample size was 720. Analysis of the data, collection tool and standard questionnaire construction was achieved. In this study, 32.4 percent of students enjoyed modest motivation condition. 23.3 percent were smokers and 5.6 percent seemed to have used illicit drugs, 40.6 percent of the students exercised regularly. The findings of this research proved that there is a significant correlation between smoking status, alcohol consumption, physical involvement, high risk sexual behavior, watching movies, non-moral condition of the safety belt and academic motivation [P<0.05] There was a significant correlation between the amount of study hours and academic motivation [P<0.05]. In order to promote academic motivation in students, both students and teachers should become more acquainted with workshop models and also, students leisure time activities should be analyzed and they should be attracted towards scientific and community organizations

effects of a single session of aerobic activity and sauna on serum aldostrone concentration: a comparison

Aldostrone is the most physiologically important mineralocorticoid released from the adrenal cortex. The basic function of this hormone is increasing sodium and chloride reabsorption and potassium secretion in the distal tubules of the kidneys and the secretional ducts of sweat glands. The aim of this study was to compare the effects of one session aerobic activity and sauna on serum aldostrone hormone concentration. Subjects were 15 football players of Shaheed Beheshti University, who had had at least 3 weekly sessions of physical activity regularly for 6 weeks. Blood samples were taken before and after aerobic activity and sauna. The data were analyzed using mean and standard deviation for statistical description, and dependent t-test for inferential analysis of data. The subject's vo2max mean was 47 +/- 4.41ml/Kg/min which is considered average. The results showed that a single session of physical activity significantly increased serum aldostrone concentration [p<0.05]. A single session in the sauna also was significantly increased serum aldostrone concentration [p<0.05]. However, there was no meaningful difference between variations of serum aldostrone concentration following aerobic activity and sauna [p>0.05]. Aldostrone concentration increased, with training and repeated heat exposure

[ frequency of cleft lip and palate and the celated risk factors in a group of neonates in the city of kerman during 1994-2002]

Orofacial clefts are the most common congenital clefts in humans. Etiology of oral clefts is multifactorial [genetic and environmental factors] and prevalence of oral clefts is different among various ethnic groups. The aim of this study was to determine the frequency of oral clefts and risk factors related to it among a group of newborns in Iran. This descriptive study was performed on 147500 files of newborns [1994-2002] in Mahdieh and Akbarabady Hospital in Tehran. The files of 193 files of newborns with oral clefts, 240 normal newborns as control group and their mothers were evaluated. Demographic data along with information about [sex, weight, prematurity, type of oral clefts] of newborns and age, drug consumption and familial matrimony of mothers were recorded. Data were analized by SPSS 10 software and the Chi-square test. Out of totally 147500 newborns 193 cases had oral clefts [1.3 for 1000 birth], 46.11% had cleft lip+cleft palate], 29.01% had [cleft lip] and 24.87% had cleft palate]. Male to female ratio was 1.27. Oral clefts were significantly higher in low weight newborns [<2500 gr] [P<0.001, OR= 3.2]. A significant relationship was found between familial matrimony of parents [P<0.001, OR=27], age of mother and systemic disease the mother and organic disorders. [P=0.04, OR=2.6, OR=2.3] with oral cleft in new borns. In 50% of newborns with cleft palate had other skeletal. The present study showed that frequency of oral clefts in the studied population was 1.3 for 1000 births, which is similar to other research results in Iran. On the base of this study low birth weight of newborns [<2500 gr], familial matrimony of parents, age of mother and systemic disease of her and large size family are the most predisposing factors associated with oral clefts, respectively A prenatal care program for pregnant women and genetic consultation in high risk groups is recomended

Preliminary studies on reproductive activities of local Abadeh does, Fars province, southern Iran

No published information are available on the reproductive indices of local Abadeh does reared in northern Fars province, southern Iran. This study was conducted to determine the duration of the breeding season, and the length and duration of the oestrous cycle. Twenty single parity 2-year-old does from Abadeh [weighing 19-26 kg] were purchased and transferred to the School of Veterinary Medicine of University of Shiraz. They had access to alfalfa hay, water ad libitum and natural light. Vasectomised teaser buck was turned with the flock and observation was made every 12 hrs during the day for standing heat detection, from late-August [2003] to late-August [2004]. To determine the onset of reproductive activity as well as occurrence of silent oestrus, blood samples were collected from jugular vein every 10 days. Following the onset of breeding season and observation of standing heat, 10 does were randomly selected in their 2nd oestrous cycle for twice weekly blood sampling. Serum progesterone concentration was determined using a commercial radioimmunoassay kit. It was found that silent oestrus occurs mostly in early breeding season. The first standing heat was observed in mid-September which was considered as the onset of breeding season. Occurrence of standing oestrus increased through October, November and December. The peak of standing oestrus was recorded during late-October to early, mid-November. The mean +/- SD duration of the oestrous cycle was 19.7 +/ 1.1 days and the mean +/- SD length of oestrus was 23.8 +/- 12.3 hrs. The mean [ +/- SD] concentrations of serum progesterone in days 0 [day of standing heat] to 4, varied between 0.1 and 0.8 ng/ml. Concentrations of progesterone during the luteal phase varied between 2.7 and 3.9 ng/ml. The results of progesterone assay during oestrous cycle indicate that the follicular and luteal phases last about 45 days and 14 days, respectively. In conclusion, oestrus activity in local Abadeh does is highly seasonal with a peak of activity being observed during the late-October to the end of November

[Application of publication bias detection methods in evaluating the effect of albendazole in treating patients with ascaris and trichocephal]

Meta analysis is a statistical method to combine the findings of a set of large number of published individual studies and re-analyse them. The use of meta-analysis methods in medical research has been increased, noticeably, in resent years. However, one of the major shortcomings in such analysis is that the researcher, could not access all conducted studies in the area of concern. This serious problem is called publication bias, and may lead to a misleading conclusion. In present study a meta analysis was carried out to evaluate the effect of albendazole in treating patients with ascaris and trichocephal and different publication bias detection methods were compared. Data were gathered from 25 clinical trials, having two treatment groups and binary outcomes, published in international indexed journals during 1982-2000. The main objectives of all these studies were to compare the performance of single dose of albendazole to treat patients with ascaris and tricocephal parasites. Total number of participants, number of patients with ascaris and tricocephal and cure rates were recorded for each study. Log odds ratio and its variance were calculated for each study and then estimated for the overall researches using meta-analysis methods. Funnel plot, Begg correlation method, two regression methods introduced by Egger and two regression methods based on Funnel plot were used and compared in detecting publication bias. SAS software was employed for this mean. Meta analysis showed that albendazole has 10.3 [95%CI: 8.35-12.65] times better performance in curing ascaris patients compared to those with tricocephal [log odds ratio 2.33]. All the employed procedures showed similar and consistent results which confirmed non-significant publication bias. However, this consistency may not occur all the time. Since this consistency may not occur all the time, it is recommended not to rely on results of only one method, but comparing and selecting a powerful method which fits the data structure