Assessment of skyshine photon dose rates from 9 and 18 MV medical linear accelerators

Background: skyshine describes the radiation scattered by the atmosphere above a LINAC facility to a point on the ground. The aim of this study was to measure the skyshine photon dose rates from two different [9 MV and 18 MV] medical linear accelerators

Materials and Methods: the photon beam was directed upward [180 degree gantry position], with a maximum photon field size [40 × 40 cm2] at the isocenter. Measurements were obtained around the external points selected outside the room facilities at a horizontal distance from the target by the calibrated RDS-110 survey meter at four points around the isocenter

Results: the measured values of the skyshine photon exposure rates at four points for 9 MV and 18 MV were 0.6, 0.5, 0.5, and 0.4 microSv/h, and 0.6, 0.4, 0.4, and 0.5 micro Sv/h, respectively. All the measured skyshine photon exposure rates were lower than the values recommended by NCRP 147

Conclusion: there is a poor agreement between the measured and the calculated values; therefore it seems that caution is needed while using the equations available in NCRP 147 or 151

[Thyroid exposure in brain CT-scan and skull X-ray, using different levels of mA and Kvp with and without thyroid shield]

Background and aim: Nowadays, thyroid exposure is a major concern in skull radiological imaging. The aim of this study was to evaluate thyroid exposure in brain CT-scan and skull X-ray, using different levels of Kvp [Kilovoltd peak] and mA, with and without thyroid shield

Methods: In this descriptive- analytic study, 350 outpatients were selected randomly. Two TLD-100 chips [Thermo Luminescence Dosimeter] were placed on the thyroid of each patient. Three levels of mA were applied in brain CT-scan [210 patients] and two levels of Kvp were used in routine skull X-rays [140 patients]. The experiments were performed with and without thyroid shield. The TLDs were read and the statistical analysis was performed using student-t test

Results: During brain CT-scan, decreasing current intensity from 150 to 125 mA, significantly decreased the thyroid exposure from 101+/-9.38 to 82.2+/-8.04 mili rem [P<0.01]. Using a thyroid shield extremely reduced the thyroid exposure to 29+/-5.83 mili rem [P<0.01]. In routine skull x-rays, increasing voltage from 60 to70 Kvp, significantly decreased the thyroid exposure from 72.6+/-7.74 to 67+/-8.41 mili rem [P<0.05]. Moreover, using the thyroid shield remarkably reduced the thyroid exposure to 19.6+/-1.82 mili rem [P<0.05]

Conclusions: Using lower levels of mA in brain CT-scans and higher levels of Kvp in skull X-rays, decrease thyroid exposure. Furthermore, using thyroid shield during X-ray examinations of the skull remarkably reduces thyroid exposure

Association of milk yield and body condition score indices with the commencement of luteal activity after parturition in high producing dairy cows

The aim of the present study was to investigate the relation between different indices of milk yield and body condition score [BCS] with the commencement of the luteal activity [C-LA] during the postpartum period in high producing dairy cows. Seventy-one multiparous healthy [free of detectable reproductive disorders] Holstein dairy cows [mean peak milk yield = 56.7 +/- 7.4 kg] were used in the present study. Transrectal ultrasound scanning was performed twice weekly from the 1st to the 8th week postpartum. Blood monitored weekly after calving. Cows with serum P[4] concentrations >/= 1 ng/ml on at least 2 consecutive blood samplings were considered to have commenced luteal activity. The C-LA was observed in 51 out of 71 cows [71.8%] earlier than 45 days postpartum, while 20 out of 71 cows [28.2%] showed the C-LA later than 45 days postpartum. Among the indices defined for the milk yield pattern in the present study, difference in milk yield between the 1st week and the peak of milk yield were significantly [P /= 1 unit BCS during the same 3rd week postpartum showed their C-LA significantly later than those cows losing less BCS during the same interval [P

[Diagnostic value of PD- fat suppression and T2 gradient echo MRI sequences in diagnosis of cruciate ligament and meniscal lesions]

Knee MRI has drawn attention due to its non-invasiveness and its high accuracy. Few reports about the accuracy of PDFS sequences for diagnosis of injured menisci and cruciate ligaments have been published. This study was performed to compare the diagnostic value of proton density with fat suppression [PDFS] and T2 gradient echo [T2 GRE] MRI sequences in injured menisci and cruciate ligaments of knee. This was a descriptive and analytical study. The sample size included 100 cases. In this study the diagnostic value of MRI with PDFS sequence and common methods [T2 GRE] evaluated and compared with each other. Considering the arthroscopy results as a gold standard, the sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV] and accuracy of the different sequences were calculated. This study included 100 patients; 79 males [79%] and 21 females [21] with a mean age of 27.8 +/- 9.04 years. Sensitivity, specificity, PPV,NPV and accuracy of sequences for detection of medial meniscal tear were 96.05%, 95.83%, 98.64%, 88.46% and 96% respectively, and for lateral meniscal tear was 90%, 100%, 100%, 100% and 97%. All the above mentioned parameters in ACL tears were 100%. PDFS sequence can be used in the evaluation of knee injuries as a reliable part of the knee imaging protocol and can be a good alternative for the nonfat-suppressive sequences in these patients

[Effect of wild pistachio oil on serum leptin concentration and thyroid hormones in the male rat]

Unsaturated fatty acids are known to decrease serum leptin level. Considering that wild pistachio oil is a rich source of UFA and the reciprocal effects between leptin and thyroid hormones, the aim of the present study was to investigate the impact of dietary wild pistachio oil on serum leptin concentration and its relationship with thyroid hormones. We took 28 healthy adult male rats and divided them randomly in to the four groups; group 1 a control, and the other 3 groups received a normal diet without, 5, 10 and 20% of wild pistachio oil, respectively. RIA for thyroid hormones assay [T3 and T4] and ELISA for leptin, fT3 and fT4 measurement were used. After 60 days, serum leptin levels reduced with increasing wild pistachio oil concentration in the diet; in the control group with normal diet, no significant alterations were seen. This reduction also was not statistically significant in the 10% wild pistachio oil group, whereas differences between groups were significant, indicating the increasing effects of increased amounts of wild pistachio oil percent on the reduction process observed. Pearson correlation coefficients were calculated between leptin and thyroid hormones in the different sampling times. Control group did not have any significant correlation. In group 2 [fed with 5% wild pistachio oil], leptin concentration had a negative significant correlation with T4 and fT3 and a positive significant correlation with fT4 in the third stage of sampling [day 30]. A positive significant correlation between leptin concentration and fT4 in the fifth stage of bleeding [day 60] was observed in group 3 [fed with 10% wild pistachio oil]. In group 4 [fed with 20% wild pistachio oil] a significant negative correlation between leptin concentration and fT3 was observed in the second stage of sampling [day 15]. Wild pistachio oil has a high content of unsaturated fatty acids, and reductions in serum leptin levels in the rats studied can be due to these acids. Oral consumption of wild pistachio oil has a positive effect on reduction leptin and LDL-cholesterol thyroid hormones and prevention of cardiovascular diseases

Activity of urinary enzymes in Iranian dromedary camels

Determination of the reference values of aspartateaminotransferase [AST], alanine aminotransferase [ALT],alkaline phosphatase [ALP], lactate dehydrogenase [LDH] and gamma glutamyltransferase [GOT] in the urine ofclinically healthy Iranian dromedary camels. Descriptive study. Fifty clinically healthy adult camels [Camelus dromedaries].Urine samples were collected from fiftyclinically healthy adult camels in identical nutritional andmanagernental conditions.Urine specimens werelyophilized and the activity of AST, ALT, ALP, LDH andGOT was measured by routine colorimetric methods. Also,urinalysis and measurement of urine creatinine wereperformed. The data were analysed by analysis ofVariance [ANOVA], Duncan's multiple range test andregression analysis. LDH and GGT showed the highest and the lowestactivity of urinary enzymes were related to LDH and GGT,respectively. Urine pH was alkaline. The concentration ofcreatinine in the urine of Iranian camels was relativelyhigh. According to urinalysis, the urine of Iranian camelswas normal. Significant positive correlations wereobserved between GGT activity and urine creatinine [P<0.05; r=0.26] and ALT activity and specific gravity [P<0.05; r=0.27], respectively. The activity of AST, ALT, ALP, LDH andGGT in the urine of Iranian camels can be used as indicesfor diagnosing renal disorders

[Studies on the effects of turpentine powder on the serum concentration of lipids and lipoproteins of female rabbits]

To Study the effects of turpentine powder on the concentration of lipids and lipoproteins of rabbit [as an animal model for human studies].Experimental Study.30 healthy female rabbits.30 healthy female rabbits were chosen and thenrandomly allocated into 6 groups of 5 rabbits each. Differentpercent ages of turpentine powder [10% and 100%] and oilcompounds [vegetable oil, cholesterol and animal oil] weregiven to each group, separately. Blood serum lipid andlipoprotein levels were analyzed using routine laboratorymethods.Analysis of variance and Duncan'smultiple range test.Treatment with 10% and 100% turpentine powderhad significant decreasing effect on Serum triglyceride, cholesterol, total lipid, VLDL- cholesterol and LDL-cholesterol [P<0.05] Moreover, it significantly increasedthe Serum HDL- cholesterol [P<0.05]. Treatment with 10%vagetable oil had a significant increasing effect on the serumtriglyceride and VLDL-cholesterol [P<0.05]. Followingtreatment with 10% animal oil, the concentration of HDL-cholesterol showed a significant [P<0.05] decreas while theconcentration of cholesterol and LDL-cholesterol showed asignificant increase [P<0.05].After treatment with 1%cholesterol, the concentration of serum HDL- cholesterol, LDL-cholesterol, VLDL-cholesterol, triglyceride and totallipid significantly increased [P<0.05].Treatmentwithturpentinepowderhassignificant effects on the levels of serum lipids andlipoproteins

[Studies on the effects of turpentine oil on the serum concentration of lipids and lipoproteins of male rabbits]

The effects of turpentine oil on the concentration of lipids and lipoproteins of rabbit [as an animal model for human studies] were investigated. Thirty five healthy male rabbits were chosen and then randomly allocated into 13 groups. Different percents of turpentine oil and other oil compounds like vegetable oil, cholesterol and animal oil were given to each group [5 rabbits] separately or in combination. Blood serum lipid and lipoprotein levels were analyzed using routine laboratory methods. Treatment with 10% and 20% turpentine oil had a significant decreasing effect on triglyceride, cholesterol, total lipid, VLDL- cholesterol and LDL- cholesterol [P<0.05] and a significant increasing effect on HDL- cholesterol [P<0.05]. on occasions which rabbits were fed a combination of different oils such as turpentine oil, animal oil and vegetable oil or cholesterol, varying results were obtained which showed significant differences with the control group in some instances and in some other occasions had no significant difference [P>0.05]. Treatment with turpentine oil has a significant decreasing effect on the levels of serum lipids and lipoproteins [VLDL-cholesterol and LDL- cholesterol]

[Distribution of zinc concentration in the tissues of the Iranian dromedary camel]

Objective: To determine the concentration of zinc in different tissues of apparently healthy Iranian dromedary camels. Design: Descriptive study

Animals: Fifty iranian dromedary camels

Procedure: The concentration of zinc was measured in serum, plasma, RBCs, WBCs, hair, liver, kidney [cortex and medulla], abomasum [pylore and fundus], heart [atrium and ventricle], skeletal muscle, urinary bladder and lung of 50 Iranian dromedary camels

Statistical analysis: The data were analysed statistically by analysis of variance [ANOVA]. The difference between the means were statistically estimated by the Duncans multiple range test. All values were expressed in mean [tSEM] using a significant level of [P<0.05]

Results: The concentration of zinc in the RBCs was higher than she serum, plasma and WBCs [P<0.05].The concentration of zinc in different organs was significantly different [P<.0.05]. The highest concentration of zinc was observed in the skeletal muscle and liver. In contrast, the lowest concentration of zinc was observed in the atrium of the heart

Conclusion: In suspected cases of zinc deficiency or poisoning in camels, the best sample for zinc measurement is whole blood, particularly red blood cells. In necropsy cases of zinc deficiency or poisoning, skeletal muscle and liver sampling are preferred. In live camels, biopsy can be taken from muscle and liver tissues

[Determination of blood lead and delta-aminoleavulinic acid dehydratase levels in painter building workers]

Lead toxicity causes hemotological, gastrointestinal, and neurological dysfunction in adults and children. Dust, water, paints and paint chips are still major sources of lead toxicity. Lead has been known as a highly toxic enviromental factor for a long time. In recent years several epidemiological, experimental and-clinical studies have indicated that even relatively low blood lead levels may affect the cognitive ability in young children. The following were the groups of subjects, who gave their informed consent in the study: 1-Healthy controls, fifty-four haematologically and clinically [including physical examination] male normal subjects with mean age of 45 and from different jubs served as controls, 2-Occupationally exposed subjects, fifty male painter building workers exposed to lead [mean duration of working 13 years] with a mean age of 40, were included. Subjects with any indication of coexisting iron deficiency or any abnormal findings on physical examination were excluded from the study. The standard haematological, erythrocyte delta-aminoleavulinic acid dehydratase and blood lead determinations were performed in two groups. The enzyme acitivity was significantly decreased in the occupationally exposed subjects [1304+/-146 [micro]mole L / h versus 1535+/-181, p<0.001, t=9.56] as compared to control. In occupationally exposed subjects blood lead concentrations were significantly higher than controls [1.34+/-0.6 [micro]mole/L versus 0.57+/-0.21, p<0.001, F=13.6]. In the control group there was no significant correlation between blood lead levels and logarithm of ALA-D [r=-0.21, p=0.067]]. In contrast, in exposed group a statistically significant negative correlation was noticed [r=-0.48, p<0.05]. In exposed group ferritin was significantly higher and TIBC significantly lower than in the control [76+/-23 [micro]g/L versus 58.5+/-16, p<0.01 and 47+/-15 [micro]mole/L versus 65+/-17, p<0.01 respectively]. It is generally accepted that erythrocyte ALA-D activity is the most sensitive and specific biochemical index of acute and chronic lead poisoning. Since low blood lead leveles have been associated with decline in intelligence quotient, screening programs in urban centers and occupationally exposed workers are now identifying asymptomatic individuals with elevated blood lead levels