96 research outputs found
international transferability of macro level safety performance functions a case study of the united states and italy
Abstract
Safety performance functions (SPFs), or crash-prediction models, have played an important role in identifying the factors contributing to crashes, predicting crash counts and identifying hotspots. Since a great deal of time and effort is needed to estimate an SPF, previous studies have sought to determine the transferability of particular SPFs; that is, the extent to which they can be applied to data from other regions. Although many efforts have been made to examine micro-level SPF transferability, few studies have focused on macro-level SPF transferability. There has been little transferability analysis of macro-level SPFs in the international context, especially between western countries. This study therefore evaluates the transferability of SPFs for several states in the USA (Illinois, Florida and Colorado) and for Italy. The SPFs were developed using data from counties in the United States and provincias in Italy, and the results revealed multiple common significant variables between the two countries. Transferability indexes were then calculated between the SPFs. These showed that the Italy SPFs for total crashes and bicycle crashes were transferable to US data after calibration factors were applied, whereas the US SPFs for total and bicycle crashes, with the exception of the Colorado SPF, could not be transferred to the Italian data. On the other hand, none of the pedestrian SPFs developed was transferable to other countries. This paper provides insights into the applicability of macro-level SPFs between the USA and Italy, and shows a good potential for international SPF transferability. Nevertheless, further investigation is needed of SPF transferability between a wider range of countries
Intraoperative β-Detecting probe for radio-guided surgery in tumour resection
The development of the β− based radio-guided surgery aims to extend the technique to those tumours where surgery is the only possible treatment and the assessment of the resection would most profit from the low background around the lesion, as for brain tumours. Feasibility studies on meningioma and gliomas already estimated the potentiality of this new treatment. To validate the technique, a prototype of the intraoperative probe detecting β− decays and specific phantoms simulating tumour remnant patterns embedded in healthy tissue have been realized. The response of the probe in this simulated environment is tested with dedicated procedures. This document discusses the innovative aspects of the method, the status of the developed intraoperative β− detecting probe and the results of the preclinical tests
Asthmatic Patients with Vitamin D Deficiency have Decreased Exacerbations after Vitamin Replacement
Background: Intervention studies with vitamin D in asthma are inconclusive for several reasons, such as inadequate dosing or duration of supplementation or uncontrolled baseline vitamin D status. Our aim was to evaluate the benefit of long term vitamin D add-on in asthmatic patients with actual vitamin D deficiency, that is a serum 25-hydroxy vitamin D (25-OHD ) below 20 ng/mL. Methods: Serum 25-OHD, asthma exacerbations, spirometry and inhaled corticosteroids (CS) dose were evaluated in a cohort of 119 asthmatic patients. Patients with deficiency were evaluated again after one year vitamin supplementation. Results: 25-OHD was low in 111 patients and was negatively related to exacerbations (p < 0.001), inhaled CS dose (p = 0.008) and asthma severity (p = 0.001). Deficiency was found in 90 patients, 55 of whom took the supplement regularly for one year, while 24 discontinued the study and 11 were not adherent. Patients with vitamin D deficiency after 12 months supplementation showed significant decrease of exacerbations (from 2.6 ± 1.2 to 1.6 ± 1.1, p < 0.001), circulating eosinophils (from 395 ± 330 to 272 ± 212 106/L, p < 0.001), and need of oral CS courses (from 35 to 20, p = 0.007) and improvement of airway obstruction. Conclusions: Asthma exacerbations are favored by vitamin D deficiency and decrease after long-term vitamin D replacement. Patients who are vitamin D deficient benefit from vitamin D supplementation
Fast emitting nanocomposites for high-resolution ToF-PET imaging based on multicomponent scintillators
Time-of-Flight Positron Emission Tomography is a medical imaging technique,
based on the detection of two back-to-back {\gamma}-photons generated from
radiotracers injected in the body. Its limit is the ability of employed
scintillation detectors to discriminate in time the arrival of {\gamma}-pairs,
i.e. the coincidence time resolution (CTR). A CTR < 50 ps that would enable
fast imaging with ultralow radiotracer dose. Monolithic materials do not have
simultaneously the required high light output and fast emission
characteristics, thus the concept of scintillating heterostructure is proposed,
where the device is made of a dense scintillator coupled to a fast-emitting
light material. Here we present a composite polymeric scintillator, whose
density has been increased upon addition of hafnium oxide nanoparticles. This
enhanced by +300% its scintillation yield, surpassing commercial plastic
scintillators. The nanocomposite is coupled to bismuth germanate oxide (BGO)
realizing a multilayer scintillator. We observed the energy sharing between its
components, which activate the nanocomposite fast emission enabling a net CTR
improvement of 25% with respect to monolithic BGO. These results demonstrate
that a controlled loading with dense nanomaterials is an excellent strategy to
enhance the performance of polymeric scintillators for their use in advanced
radiation detection and imaging technologies
Monitoring of hadrontherapy treatments by means of charged particle detection
The interaction of the incoming beam radiation with the patient body in hadrontherapy
treatments produces secondary charged and neutral particles, whose detection can be
used for monitoring purposes and to perform an on-line check of beam particle range. In
the context of ion-therapy with active scanning, charged particles are potentially attractive
since they can be easily tracked with a high efficiency, in presence of a relatively low
background contamination. In order to verify the possibility of exploiting this approach
for in-beam monitoring in ion-therapy, and to guide the design of specific detectors, both
simulations and experimental tests are being performed with ion beams impinging on
simple homogeneous tissue-like targets (PMMA). From these studies, a resolution of the
order of few millimeters on the single track has been proven to be sufficient to exploit
charged particle tracking for monitoring purposes, preserving the precision achievable
on longitudinal shape. The results obtained so far show that the measurement of charged
particles can be successfully implemented in a technology capable of monitoring both
the dose profile and the position of the Bragg peak inside the target and finally lead to
the design of a novel profile detector. Crucial aspects to be considered are the detector
positioning, to be optimized in order to maximize the available statistics, and the capability
of accounting for the multiple scattering interactions undergone by the charged
fragments along their exit path from the patient body. The experimental results collected
up to now are also valuable for the validation of Monte Carlo simulation software tools
and their implementation in Treatment Planning Software packages
Towards a Radio-guided Surgery with Decays: Uptake of a somatostatin analogue (DOTATOC) in Meningioma and High Grade Glioma
A novel radio guided surgery (RGS) technique for cerebral tumors using
radiation is being developed. Checking the availability of a
radio-tracer that can deliver a emitter to the tumor is a
fundamental step in the deployment of such technique. This paper reports a
study of the uptake of 90Y labeled (DOTATOC) in the meningioma and the high
grade glioma (HGG) and a feasibility study of the RGS technique in these cases.Comment: 21 pages, 5 figure
Nuove ricerche nel settore termale e del cd. vigneto della villa imperiale del Pausilypon di Napoli.
Withdrawal of mechanical ventilation in amyotrophic lateral sclerosis patients: a multicenter Italian survey
Background: Law 219/2017 was approved in Italy in December 2017, after a years-long debate on the autonomy of healthcare choices. This Law, for the first time in Italian legislation, guarantees the patient's right to request for withdrawal of life-sustaining treatments, including mechanical ventilation (MV). Objective: To investigate the current status of MV withdrawal in amyotrophic lateral sclerosis (ALS) patients in Italy and to assess the impact of Law 219/2017 on this practice. Methods: We conducted a Web-based survey, addressed to Italian neurologists with expertise in ALS care, and members of the Motor Neuron Disease Study Group of the Italian Society of Neurology. Results: Out of 40 ALS Italian centers, 34 (85.0%) responded to the survey. Law 219/2017 was followed by an increasing trend in MV withdrawals, and a significant increase of neurologists involved in this procedure (p 0.004). However, variations across Italian ALS centers were observed, regarding the inconsistent involvement of community health services and palliative care (PC) services, and the intervention and composition of the multidisciplinary team. Conclusions: Law 219/2017 has had a positive impact on the practice of MV withdrawal in ALS patients in Italy. The recent growing public attention on end-of-life care choices, along with the cultural and social changes in Italy, requires further regulatory frameworks that strengthen tools for self-determination, increased investment of resources in community and PC health services, and practical recommendations and guidelines for health workers involved
Localization of anatomical changes in patients during proton therapy with in-beam PET monitoring: a voxel-based morphometry approach exploiting Monte Carlo simulations
Purpose: In-beam positron emission tomography (PET) is one of the modalities that can be used for in vivo noninvasive treatment monitoring in proton therapy. Although PET monitoring has been frequently applied for this purpose, there is still no straightforward method to translate the information obtained from the PET images into easy-to-interpret information for clinical personnel. The purpose of this work is to propose a statistical method for analyzing in-beam PET monitoring images that can be used to locate, quantify, and visualize regions with possible morphological changes occurring over the course of treatment. Methods: We selected a patient treated for squamous cell carcinoma (SCC) with proton therapy, to perform multiple Monte Carlo (MC) simulations of the expected PET signal at the start of treatment, and to study how the PET signal may change along the treatment course due to morphological changes. We performed voxel-wise two-tailed statistical tests of the simulated PET images, resembling the voxel-based morphometry (VBM) method commonly used in neuroimaging data analysis, to locate regions with significant morphological changes and to quantify the change. Results: The VBM resembling method has been successfully applied to the simulated in-beam PET images, despite the fact that such images suffer from image artifacts and limited statistics. Three dimensional probability maps were obtained, that allowed to identify interfractional morphological changes and to visualize them superimposed on the computed tomography (CT) scan. In particular, the characteristic color patterns resulting from the two-tailed statistical tests lend themselves to trigger alarms in case of morphological changes along the course of treatment. Conclusions: The statistical method presented in this work is a promising method to apply to PET monitoring data to reveal interfractional morphological changes in patients, occurring over the course of treatment. Based on simulated in-beam PET treatment monitoring images, we showed that with our method it was possible to correctly identify the regions that changed. Moreover we could quantify the changes, and visualize them superimposed on the CT scan. The proposed method can possibly help clinical personnel in the replanning procedure in adaptive proton therapy treatments
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