Reducing Uncertainty in Head and Neck Radiotherapy with Plastic Robotics

One of the greatest challenges in achieving accurate positioning in head and neck radiotherapy is that the anatomy at and above the cervical spine does not act as a single, mechanically rigid body. Current immobilization techniques contain residual uncertainties that are especially present in the lower neck that cannot be reduced by setting up to any single landmark. The work presented describes the development of a radiotherapy friendly mostly-plastic 6D robotic platform for positioning independent landmarks, (i.e., allowing remote, independent positioning of the skull relative to landmarks in the thorax), including analysis of kinematics, stress, radiographic compatibility, trajectory planning, physical construction, and phantom measurements of correction accuracy. No major component of the system within the field of imaging or treatment had a measured attenuation value greater than 250 HU, showing compatibility with x-ray-based imaging techniques. Relative to arbitrary overall setup errors of the head (min = 1.1 mm, max = 5.2 mm vector error) the robotic platform corrected the position down to a residual overall error of 0.75 mm +/- 0.33 mm over 15 cases as measured with optical tracking. This device shows the potential for providing reductions to dose margins in head and neck therapy cases, while also reducing setup time and effort

Radiotherapy-Compatible Robotic System for Multi-Landmark Positioning in Head and Neck Cancer Treatments

The spine flexibility creates one of the most significant challenges to proper positioning in radiation therapy of head and neck cancers. Even though existing immobilization techniques can reduce the positioning uncertainty, residual errors (2–3 mm along the cervical spine) cannot be mitigated by single translation-based approaches. Here, we introduce a fully radiotherapy-compatible electro-mechanical robotic system, capable of positioning a patient’s head with submillimeter accuracy in clinically acceptable spatial constraints. Key mechanical components, designed by finite element analysis, are fabricated with 3D printing and a cyclic loading test of the printed materials captures a great mechanical robustness. Measured attenuation of most printed components is lower than analytic estimations and radiographic imaging shows no visible artifacts, implying full radio-compatibility. The new system evaluates the positioning accuracy with an anthropomorphic skeletal phantom and optical tracking system, which shows a minimal residual error (0.7 ± 0.3 mm). This device also offers an accurate assessment of the post correction error of aligning individual regions when the head and body are individually positioned. Collectively, the radiotherapy-compatible robotic system enables multi-landmark setup to align the head and body independently and accurately for radiation treatment, which will significantly reduce the need for large margins in the lower neck

M & L Jaargang 22/1

Jan Van Hove Een ambtenaar maakt het verschil.Daniël Ostyn Het Europees Monumentenjaar 1975. Een doorbraak in de monumentenzorg.Kamiel D\u27Hooghe Aan Edgard Goedleven: een hommage met grand-jeu.Paul Van den Bremt - Landschapszorg, de groene bril van Edgard Goedleven.Robert Piessens Edgard Goedleven, penningmeester van de Vereniging voor het bevorderen van het Belgisch trekpaard.Suzanne Van Aerschot-Van Haeverbeeck Inventarisatie van het bouwkundig erfgoed: een eindeloos verhaal.Mark Fierlafijn Van cultureel tot grondgebonden. Een beknopt overzicht van de evolutie van de decreet- en regelgeving inzake monumenten en landschappen.Suzanne Van Aerschot-Van Haeverbeeck Vlaams erfgoed Werelderfgoed. Een achterstand ingehaald.André Matthys Edgard Goedleven et la politique patrimoniale internationale.Marjan Buyle Een monument is meer dan een gevel alleen.Piet Jaspaert De financier en organisator.Marcel M. Celis De verbeelding aan de macht: M&L van 1 tot 127

Sustained proliferation in cancer: mechanisms and novel therapeutic targets

Proliferation is an important part of cancer development and progression. This is manifest by altered expression and/or activity of cell cycle related proteins. Constitutive activation of many signal transduction pathways also stimulates cell growth. Early steps in tumor development are associated with a fibrogenic response and the development of a hypoxic environment which favors the survival and proliferation of cancer stem cells. Part of the survival strategy of cancer stem cells may manifested by alterations in cell metabolism. Once tumors appear, growth and metastasis may be supported by overproduction of appropriate hormones (in hormonally dependent cancers), by promoting angiogenesis, by undergoing epithelial to mesenchymal transition, by triggering autophagy, and by taking cues from surrounding stromal cells. A number of natural compounds (e.g., curcumin, resveratrol, indole-3-carbinol, brassinin, sulforaphane, epigallocatechin-3-gallate, genistein, ellagitannins, lycopene and quercetin) have been found to inhibit one or more pathways that contribute to proliferation (e.g., hypoxia inducible factor 1, nuclear factor kappa B, phosphoinositide 3 kinase/Akt, insulin-like growth factor receptor 1, Wnt, cell cycle associated proteins, as well as androgen and estrogen receptor signaling). These data, in combination with bioinformatics analyses, will be very important for identifying signaling pathways and molecular targets that may provide early diagnostic markers and/or critical targets for the development of new drugs or drug combinations that block tumor formation and progression

Effect of Village-wide Use of Long-Lasting Insecticidal Nets on Visceral Leishmaniasis Vectors in India and Nepal: A Cluster Randomized Trial

Visceral leishmaniasis (VL) is a vector-borne disease causing at least 60,000 deaths each year amongst an estimated half million cases, and until recently there have been no significant initiatives to reduce this burden. However, in 2005, the governments of India, Bangladesh and Nepal signed a memorandum of understanding at the World Health Assembly in Geneva for the elimination of the disease by 2015. In the absence of an effective vaccine, the program will rely on the active detection and prompt treatment of cases throughout the endemic region, combined with a recurrent indoor residual spraying (IRS) of all villages at risk. Vector control programs based on IRS are notorious for failing to maintain comprehensive spray coverage over time owing to logistical problems and lack of compliance by householders. Long-lasting insecticidal nets (LNs) have been postulated as an alternative or complement to IRS. Here we describe how comprehensive coverage of LN in trial communities reduced the indoor density of sand flies by 25% compared to communities without LNs. This provides an indication that LNs could be usefully deployed as a component of the VL control program in the Indian subcontinent

A Simulation Study of a Radiofrequency Localization System for Tracking Patient Motion in Radiotherapy

One of the most widely used tools in cancer treatment is external beam radiotherapy. However, the major risk involved in radiotherapy is excess radiation dose to healthy tissue, exacerbated by patient motion. Here, we present a simulation study of a potential radiofrequency (RF) localization system designed to track intrafraction motion (target motion during the radiation treatment). This system includes skin-wearable RF beacons and an external tracking system. We develop an analytical model for direction of arrival measurement with radio frequencies (GHz range) for use in a localization estimate. We use a Monte Carlo simulation to investigate the relationship between a localization estimate and angular resolution of sensors (signal receivers) in a simulated room. The results indicate that the external sensor needs an angular resolution of about 0.03 degrees to achieve millimeter-level localization accuracy in a treatment room. This fundamental study of a novel RF localization system offers the groundwork to design a radiotherapy-compatible patient positioning system for active motion compensation

Residual activity and integrity of PermaNet® 2.0 after 24 months of household use in a community randomised trial of long lasting insecticidal nets against visceral leishmaniasis in India and Nepal.

The World Health Organization (WHO) recommends several brands of long lasting insecticidal net (LN) for protection against insect vectors but also advises national programmes to monitor and evaluate performance under local conditions to help them select the most suitable LN for their setting. During the course of a community randomised trial of LNs against visceral leishmaniasis in northern India and Nepal, opportunity arose to assess the efficacy of PermaNet 2.0 (Vestergaard-Frandsen, Denmark) after two years of use against sandfly vectors. Between 63% (India) and 78% (Nepal) of LNs became holed over the course of two years, deltamethrin residues fell from 55 mg/m(2) to an average of 11.6 mg/m(2) (India) and 27.9 mg/m(2) (Nepal), but on the basis of bioassay criteria all LNs tested still met the WHO Pesticide Evaluation Scheme standard for LN effectiveness. Nets had on average only been washed 2.5 times (India) and 0.6 times (Nepal) by householders over the course of two years. The loss of insecticide was attributed to factors which had little or nothing to do with washing, such as handling, friction and torsion during daily use. Under conditions pertaining in this region of south Asia, and for two years at least, this brand of net continues to meet the criteria established by WHO for LNs

The associations of ACE polymorphisms with physical, physiological and skill parameters in adolescents

Genetic variation in the human Angiotensin I-Converting Enzyme (ACE) gene has been associated with many heritable traits, including physical performance. Herein we report the results of a study of several physical, physiological and skill parameters and lifestyle in 1027 teenage Greeks. We show that there is a strong association (P less than 0.001) between the ACE I/D (insertion/deletion) polymorphism and both handgrip strength and vertical jump in females, homozygotes for the I-allele exhibiting higher performance-related phenotype scores, accounting for up to 4.5% of the phenotypic variance. The association is best explained by a model in which the D-allele is dominant, with the mean phenotypic value in the I/D heterozygotes being close to that of the mean of the DD homozygotes. The association acts across the phenotype distribution in a classical polygenic manner. Other polymorphisms that define major ACE haplotypes in European populations (rs4424958, rs4311) show weaker associations with these performance-related phenotypes than does I/D. Similarly, diplotypes defined by these polymorphisms do not explain significantly larger amounts of the variance than I/D alone. As ACE I/D is the polymorphism most strongly associated with circulating ACE activity in European populations, we propose that the functional allelic differences that influence ACE activity also mediate the associations with the performance-related phenotypes studied here