Evaluation and comparison of dosimetric parameters in PTV for prostate cancer via step and shoot IMRT and 3DCRT

The aim of radiation therapy treatment planning is to achieve an optimal balance between delivering a high dose to target volume and a low dose to healthy tissues. The integral dose, conformity and homogeneity indexes, hence, are the important guidance for predicting the radiation effects and choosing the optimal treatment plan. The goal of this study is to compare and investigate the aforementioned parameters in 3DCRT vs. IMRT plan. In order to evaluate dosimetric parameters, data from five patients with prostate cancer, planned by IMRT and 3DCRT were obtained. Prescribed doses for IMRT procedure and 3DCRT were 80Gy and 70 Gy, respectively. Also, the target coverage was achieved with 95% of the prescribed dose to 95% of the PTV in 3DCRT and 95% of the prescribed dose to 98% of the PTV in IMRT method. A total of thirty IMRT and 3DCRT plans were performed for evaluation of dosimetric parameters (for each patient both treatment plans, step and shoot IMRT and 3DCRT with 6, 10 and 18MV energies) were done. The integral dose was calculated as the mean- dose times the volume of the structure. The mean integral dose (ID) received by rectum for 3DCRT was almost 1.01% greater than IMRT while in bladder mean value of ID for IMRT was approximately 1.68% higher than 3DCRT. For PTV in IMRT the ID of target volume had the biggest value (1.14%) compared to that of 3DCRT. Dose conformity in PTV volume in S.A.S and 3DCRT was almost equal. The same outcome was achieved in homogeneity index. The results of this study shows that IMRT method leads to adequate target dose coverage while the prescribed dose for this modality is higher than 3DCRT. IMRT has the ability of increasing the maximum dose to tumor region and improves conformity and homogeneity indexes in target volume and also reduces dose to OAR

Genetic variability and differentiation of common Kilka fish (Clupeonella cultriventris Nordmann, 1840) in the southern coasts of Caspian Sea

A total of 120 samples of adult common Kilka fish (Clupeonella cultriventris) were collected during spring and summer from the southern coasts of Caspian Sea (Bandar Anzali and Babolsar). Fifteen sets of microsatellite primers were developed from Clupeidae being tested on genomic DNA of common Kilka. Allele frequency, observed and expected heterozygosity, FST, RST, FIS index were determined. Five primer sets as polymorphic loci were used to analyze the genetic variation in adults of the common Kilka population. Results revealed that average alleles per locus was 13.1 (range 5 to 22 alleles per locus in regions, Ne=9.5). All sampled regions contained private alleles. Average observed and expected heterozygosity was 0.348 and 0.877, respectively. Deviations from Hardy Weinberg equilibrium were observed in most cases. FST, RST and gene flow estimates in AMOVA and the genetic distance between populations indicated that the genetic difference among the studied populations was pronounced. The data generated in this study provide primary information on the genetic variation and differentiation in populations of Caspian common Kilka

Assessment of subclinical left ventricular dysfunction in patients with chronic mitral regurgitation using torsional parameters described by tissue doppler imaging

Background: Left ventricular (LV) twist is due to oppositely directed apical and basal rotation and has been proposed as a sensitive marker of LV function. We sought to assess the impact of chronic pure mitral regurgitation (MR) on the torsional mechanics of the left human ventricle using tissue Doppler imaging. Methods: Nineteen severe MR patients with a normal LV ejection fraction and 16 non-MR controls underwent conventional echocardiography and apical and basal short-axis color Doppler myocardial imaging (CDMI). LV rotation at the apical and basal short-axis levels was calculated from the averaged tangential velocities of the septal and lateral regions, corrected for the LV radius over time. LV twist was defined as the difference in LV rotation between the two levels, and the LV twist and twisting/untwisting rate profiles were analyzed throughout the cardiac cycle. Results: LV twist and LV torsion were significantly lower in the MR group than in the non-MR group (10.38 ° ± 4.04 ° vs. 13.95 ° ± 4.27 °; p value = 0.020; and 1.29 ± 0.54 °/cm vs. 1.76 ± 0.56 °/cm; p value = 0.021, respectively), both suggesting incipient LV dysfunction in the MR group. Similarly, the untwisting rate was lower in the MR group (-79.74 ± 35.97 °/s vs.-110.96 ± 34.65 °/s; p value = 0.020), but there was statistically no significant difference in the LV twist rate. Conclusion: The evaluation of LV torsional parameters in MR patients with a normal LV ejection fraction suggests the potential role of these sensitive variables in assessing the early signs of ventricular dysfunction in asymptomatic patients

The measurement of photoneutron dose around an 18 MV Varian linear accelerator by TLD600 and TLD700 dosimeters inside the polyethylene sphere of neutron probe LB 6411

Bremsstrahlung X-rays from high-energy linear accelerators (Linacs) produce neutrons as a result ofphotonuclear reactions mainly with the different materials constituting the accelerator head. The neutronsproduced during high energy radiotherapy should be considered in terms of protection and ose escalation. Due to the very intense photon component in the Linac field causing pulse pile-up and dead-time effects indetectors, measurement of the corresponding neutron dose by active dosimeters is extremely troublesome. In this study, the neutron probe LB 6411, which active detector of 3He proportional counter tube was replaced withthe passive detectors of TLD600 and TLD700, has been used to perform neutron measurements at four pointsaround the 18 MV Varian 2100C Linac facility. The neutron dose equivalent at the distance of 1 and 2 m fromthe isocentre on the patient couch was obtained 2.2 and 0.75 mSv.Gy-1respectively. According to the results,the dose equivalent from emitted photoneutrons is not negligible and therefore treatment conditions should beoptimized. The results of this study emphasized that TLD600 and TLD700 dosimeters inside the polyethylenesphere of neutron probe LB 6411 is an appropriate choice for studying photoneutron production in the vicinity ofthe accelerato

Population genetic structure of common kilka (Clupeonella cultriventris) in the south Caspian Sea costline (Mazandaran province) using micro satellite markers

Common kilka, Clupeonella cultriventris is an economic fish in Caspian sea and we investigate population genetic structure of common kilka in the South Caspian Sea costline (Mazandaran province) using microsatellite markers. Totally, 60 individuals of adult common kilka from two seasons were sampled. Eight sets of microsatellite primers were developed from American shad and Pacific herring tested on genomic DNA of common kilka. At this point only the five successfully used primer sets and were used to analyze the genetic variation in adultsof the common kilka population. Analyses revealed that average of alleles per locus was 11.7 (Na range 6 to 17 alleles per locus). Both of sampled seasons contained private alleles. Average observed and expected heterozygosity were 0.543 and 0.866 respectively. Deviations from Hardy-Weinberg equilibrium were in most cases (P<0.01). Basis on AMOVA for both FST values among pairs them indicated a significant difference between the two seasons (P≤0.01). These results support the existence of different genetic populations along the South Caspian Sea costline (Mazandaran province) in different seasons

On the Effect of Reference Frame Motion on InSAR Deformation Estimates

For processing of interferometric synthetic aperture radar (InSAR) data, precise satellite orbits are required. These orbits are given in a reference frame with respect to which tectonic plates perform a relative motion. Neglecting this motion can cause temporally increasing baseline errors that induce large scale error ramps into the interferometric phase. The amount of error depends on the geographical location and is evaluated globally for the ENVISAT orbit. Predicted biases of deformation estimates can reach up to 7 mm/a in some areas. Whereas these biases are not separable from actual deformation signals by spatio-temporal correlation properties, they are well predictable and can easily be accounted for. A most simple correction approach consists in compensating the plate motion by modifying orbital state vectors, assuming a homogeneous velocity for the whole plate. This approach has been tested on Persistent Scatterer Interferometry (PSI) results over the area of Groningen, the Netherlands

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Intégration de données de multiples sources et systèmes robotisés pour le désherbage de cultures maraichères

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Assessment of left atrial reservoir function in mitral valve disease by tissue doppler, strain and strain rate imaging

Introduction: Mitral valve stenosis and mitral valve regurgitation still result in significant morbidity and mortality. It has been shown that atrial remodeling and atrial fibrillation may occur in these patients. We sought to investigate how pressure or volume overload in the left atrium could impact atrial deformation properties obtained via Doppler-derived velocity and strain/strain rate imaging. Methods: Thirty-six patients, comprising 17 patients with a diagnosis of moderate to severe mitral stenosis and 19 patients with a diagnosis of moderate to severe mitral regurgitation, were compared with 16 healthy subjects. Two-dimensional, pulse Doppler, and tissue Doppler transthoracic echocardiographic study was performed. Measurement of regional velocity, strain and SR profiles, peak systolic velocity, peak strain, and strain rate was performed in two segments of the four left atrial walls. Results: There was a significant decline in peak systolic velocity in the mitral stenosis patients in both annular and roof segments, but the difference was not statistically significant between the mitral regurgitation patients and the healthy subjects. Total velocity was significantly lower in the mitral stenosis patients than in the healthy subjects, but the difference was not statistically significant between the healthy subjects and the mitral regurgitation patients. Comparison of total strain showed significant differences between the three groups mainly due to a decline in strain in the mitral stenosis patients in comparison with the other two groups. Comparison of total peak systolic strain rate between the groups showed significant differences due to a significant decline in the mitral stenosis group and a non-significant decline in the mitral regurgitation group by comparison with the healthy group. Conclusion: This reduction, especially in strain and strain rate, shows that the reservoir function of the left atrium could be compromised more severely in asymptomatic mitral stenosis patients. © 2014 American Scientific Publishers All rights reserved

Echocardiographic characteristics including tissue Doppler imaging after enhanced external counterpulsation therapy.

This study assessed the effects of a course of enhanced external counterpulsation (EECP) therapy on systolic and diastolic cardiac function using echocardiography to measure left ventricular ejection fraction (LVEF), end-systolic volume (ESV), end-diastolic volume (EDV), systolic wave (Sm), early diastolic wave (Ea), Vp, E/Ea, E/Vp, and diastolic function grade in 25 patients before and after 35 hours of EECP. EECP reduced ESV and EDV and increased ejection fraction significantly in patients with baseline LVEF or = 14 (P=.032, .038, .007), baseline grade II or III diastolic dysfunction (decreased compliance) (P=.014, .032, .027), baseline Ea 50, baseline E/Ea or = 7 cm/s, and Sm > or = 7 cm/s. These results demonstrate improved systolic and diastolic function in selected patients and provide new insight into potential clinical applications of EECP