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

Fatigue analysis-based numerical design of stamping tools made of cast iron

This work concerns stress and fatigue analysis of stamping tools made of cast iron with an essentially pearlitic matrix and containing foundry defects. Our approach consists at first, in coupling the stamping numerical processing simulations and structure analysis in order to improve the tool stiffness geometry for minimizing the stress state and optimizing their fatigue lifetime. The method consists in simulating the stamping process by considering the tool as a perfect rigid body. The estimated contact pressure is then used as boundary condition for FEM structure loading analysis of the tool. The result of this analysis is compared with the critical stress limit depending on the automotive model. The acceptance of this test allows calculating the fatigue lifetime of the critical zone by using the S–N curve of corresponding load ratio. If the prescribed tool life requirements are not satisfied, then the critical region of the tool is redesigned and the whole simulation procedures are reactivated. This method is applied for a cast iron EN-GJS-600-3. The stress-failure (S–N) curves for this material is determined at room temperature under push pull loading with different load ratios R0σmin/σmax0−2, R0−1 and R00.1. The effects of the foundry defects are determined by SEM observations of crack initiation sites. Their presence in tested specimens is associated with a reduction of fatigue lifetime by a factor of 2. However, the effect of the load ratio is more important

Assessment of Multi-leaf Collimator Positional Accuracy Using Radiochromic EBT3 Film and an Electronic Portal Imaging Device

This study aimed to evaluate multi-leaf collimator (MLC) positional accuracy by using an electronic portal imaging device (EPID) and radiochromic EBT3 film. Furthermore, the MLC�s positional accuracy at different gantry and collimator angles of a Siemens ONCOR linear accelerator (linac) was evaluated. A picket fence test was performed to evaluate the MLC�s positional accuracy at various gantry and collimator angles of the linac. The EPID and the EBT3 films were sequentially irradiated seven times at 2-cm intervals by making a rectangular field (0.3 � 19 cm2). The full-width at half-maximum (FWHM) of each band (field) was calculated for all leaves by using inhouse software. Then, variations between the actual and the planned leaf locations were obtained by using the EPID and the EBT3 film at various gantry and collimator angles. The mean FWHM, acquired using the EPID and the EBT3 film ranged from 2.331 - 3.647 mm and 2.059 - 4.001 mm, respectively. Variations between the actual and the planned leaf locations were found to be affected by changes in the collimator and the gantry angles. Moreover, a -0.060 - 1.588 mm difference we seen between the result obtained from the EBT3 film and that obtained from the EPID. The mean FWHM, at most angles, for the EBT3 film was larger than that for the EPID. The findings showed average deviations for the EPID (0.001 - 0.669 mm) and EBT3 film (0.007 - 1.001 mm); these values agreed within the tolerance level (±1 mm). Furthermore, good agreement was found between the results obtained from the EPID and the EBT3 film; these two dosimetric methods can be used interchangeably, but each must be chosen considering its advantages and disadvantages. © 2020, The Korean Physical Society

A review on phytochemical and therapeutic potential of Iris germanica

OBJECTIVES: Iris germanica L. is a medicinal plant, which has a long history of uses, mainly in medieval Persia and many places worldwide for the management of a wide variety of diseases. In this study, we aimed to review ethnopharmacological applications in addition to phytochemical and pharmacological properties of I. germanica. KEY FINDINGS: Ethnomedical uses of I. germanica have been reported from many countries such as China, Pakistan, India, Iran and Turkey. The medicinal part of I. germanica is the rhizome and the roots. Based on phytochemical investigations, different bioactive compounds, including flavonoids, triterpenes, sterols, phenolics, ceramides and benzoquinones, have been identified in its medicinal parts. Current pharmacological studies represent that the plant possesses several biological and therapeutic effects, including neuroprotective, hypoglycaemic, hypolipidaemic, antimicrobial, antioxidant, antiproliferative, anti-inflammatory, antiplasmodial, antifungal, immunomodulatory, cytotoxic and antimutagenic effects. SUMMARY: Although the majority of preclinical studies reported various pharmacological activities of this plant, however, sufficient clinical trials are not currently available. Therefore, to draw a definitive conclusion about the efficacy and therapeutic activities of I. germanica and its bioactive compounds, further clinical and experimental studies are required. Moreover, it is necessary to focus on the pharmacokinetic and safety studies on the extracts of I. germanica. © The Author(s) 2021. Published by Oxford University Press on behalf of the Royal Pharmaceutical Society. All rights reserved. For permissions, please e-mail: [email protected]

Whole‐brain microscopy reveals distinct temporal and spatial efficacy of anti‐Aβ therapies

Many efforts targeting amyloid-β (Aβ) plaques for the treatment of Alzheimer's Disease thus far have resulted in failures during clinical trials. Regional and temporal heterogeneity of efficacy and dependence on plaque maturity may have contributed to these disappointing outcomes. In this study, we mapped the regional and temporal specificity of various anti-Aβ treatments through high-resolution light-sheet imaging of electrophoretically cleared brains. We assessed the effect on amyloid plaque formation and growth in Thy1-APP/PS1 mice subjected to β-secretase inhibitors, polythiophenes, or anti-Aβ antibodies. Each treatment showed unique spatiotemporal Aβ clearance, with polythiophenes emerging as a potent anti-Aβ compound. Furthermore, aligning with a spatial-transcriptomic atlas revealed transcripts that correlate with the efficacy of each Aβ therapy. As observed in this study, there is a striking dependence of specific treatments on the location and maturity of Aβ plaques. This may also contribute to the clinical trial failures of Aβ-therapies, suggesting that combinatorial regimens may be significantly more effective in clearing amyloid deposition. Keywords: Alzheimer's disease; amyloid-beta; brain; light-sheet microscopy; tissue clearin

Men, maternity and moral residue:negotiating the moral demands of the transition to first time fatherhood

This article discusses men's transition to first time fatherhood, with a focus on the way they recognise various in-tension moral demands and negotiate an appropriate role for themselves. The findings are taken from a longitudinal study, drawing on elements of grounded theory, comprising a series of face-to-face and telephone interviews with 11 men over a 9-month period from the 12(th) week of pregnancy to 8 weeks after the birth. The analysis focuses on men's feelings and experience of exclusion and participation, and their response and reaction to that experience. The findings present two descriptive themes, ‘on the inside looking in’ and ‘present but not participating’, followed by third theme ‘deference and support: a moral response’ that exposes the dilemmatic nature of men's experience and explains the participants’ apparent acceptance of being less involved. The discussion explores the concept of moral residue, arguing that while deference and support may be an appropriate role for fathers in the perinatal period it may also be a compromise that leads to feelings of uncertainty and frustration, which is a consequence of being in a genuinely dilemmatic situation

Intimal aortic sarcoma mimicking ruptured thoracoabdominal type IV aneurysm. a rare case report and review of the literature

Primary intimal aortic sarcoma represents a very rare and highly lethal medical entity. Diagnosis is made either by embolic events caused by the tumor or by surrounding tissue symptoms such as pain. Herein we report an extremely rare case of a 51-year-old man previously operated for ascending aortic aneurysm, who presented with clinical and radiological findings suggestive of a ruptured thoracoabdominal type IV aneurysm. The patient underwent radical resection of the aorta and surrounding tissue with placement of a composite 4-branched graft. The diagnosis was made by frozen section and regular histopathologic examination of the specimen and the patient received adjuvant chemotherapy. Nine months after surgery the patient is still alive and has no signs of recurrence. We review the literature and discuss the option of postoperative chemotherapy