Image quality and dose evaluation of filtered back projection versus iterative reconstruction algorithm in multislice computed tomography.

Il presente lavoro di tesi è stato svolto presso il servizio di Fisica Sanitaria del Policlinico Sant'Orsola-Malpighi di Bologna. Lo studio si è concentrato sul confronto tra le tecniche di ricostruzione standard (Filtered Back Projection, FBP) e quelle iterative in Tomografia Computerizzata. Il lavoro è stato diviso in due parti: nella prima è stata analizzata la qualità delle immagini acquisite con una CT multislice (iCT 128, sistema Philips) utilizzando sia l'algoritmo FBP sia quello iterativo (nel nostro caso iDose4). Per valutare la qualità delle immagini sono stati analizzati i seguenti parametri: il Noise Power Spectrum (NPS), la Modulation Transfer Function (MTF) e il rapporto contrasto-rumore (CNR). Le prime due grandezze sono state studiate effettuando misure su un fantoccio fornito dalla ditta costruttrice, che simulava la parte body e la parte head, con due cilindri di 32 e 20 cm rispettivamente. Le misure confermano la riduzione del rumore ma in maniera differente per i diversi filtri di convoluzione utilizzati. Lo studio dell'MTF invece ha rivelato che l'utilizzo delle tecniche standard e iterative non cambia la risoluzione spaziale; infatti gli andamenti ottenuti sono perfettamente identici (a parte le differenze intrinseche nei filtri di convoluzione), a differenza di quanto dichiarato dalla ditta. Per l'analisi del CNR sono stati utilizzati due fantocci; il primo, chiamato Catphan 600 è il fantoccio utilizzato per caratterizzare i sistemi CT. Il secondo, chiamato Cirs 061 ha al suo interno degli inserti che simulano la presenza di lesioni con densità tipiche del distretto addominale. Lo studio effettuato ha evidenziato che, per entrambi i fantocci, il rapporto contrasto-rumore aumenta se si utilizza la tecnica di ricostruzione iterativa. La seconda parte del lavoro di tesi è stata quella di effettuare una valutazione della riduzione della dose prendendo in considerazione diversi protocolli utilizzati nella pratica clinica, si sono analizzati un alto numero di esami e si sono calcolati i valori medi di CTDI e DLP su un campione di esame con FBP e con iDose4. I risultati mostrano che i valori ricavati con l'utilizzo dell'algoritmo iterativo sono al di sotto dei valori DLR nazionali di riferimento e di quelli che non usano i sistemi iterativi.

Stima del potenziale di liquefazione in terreni alluvionali di recente deposizione (sito di Isola Serafini, PC)

With the support of data collected by CPT tests on-site, in this report, we try to estimate the liquefaction potential in soils at high risk, due to the presence of sandy horizons. We began by acquiring some basic theory about the topic with the help of texts, articles and documents found in the web. The notions found here were consequently applied to two concrete case studies. 
In the first part of the work, the phenomenon of liquefaction is analyzed at a theoretical level. Moreover, we want to find out the trigger factors and the possible side effects whenever this event occurs.
In the second part of the work, we re-elaborated the data concerning tip resistance (qc) and resistance to friction side (fs) obtained by CPT tests taken in proximity of San Carlo (FE) and Isola Serafini (PC). We particularly chose to go through this specific process to estimate the land liquefaction potential. 
The main purpose is finally to compare the results of both tests and to comment on them.

Rdnet network - protocollo di comunicazione tra controller e pc tramite cavo lan

Questo documento presenta la relazione di una tesi in azienda svolta presso la ditta RCF spa a Reggio Emilia. La tesi consiste nell’apportare migliorie ad un software preesistente, che opera nel campo di dispositivi audio di diverse tipologie (es casse e mixer), i quali normalmente vengono utilizzati nel sistema d’impianto audio in un concerto. In particolare la nuova funzionalità sviluppata consiste nell’implementazione del protocollo di comunicazione tra controllore e PC mediante l’utilizzo di una connessione Ethernet.

The Equidistant Method - a novel hip joint simulation algorithm for detection of femoroacetabular impingement

A novel computerized algorithm for hip joint motion simulation and collision detection, called the Equidistant Method, has been developed. This was compared to three pre-existing methods having different properties regarding definition of the hip joint center and behavior after collision detection. It was proposed that the Equidistant Method would be most accurate in detecting the location and extent of femoroacetabular impingement.

Algorithm for femoral and periacetabular osteotomies in complex hip deformities

Residual acetabular dysplasia of the hip in most patients can be corrected by periacetabular osteotomy. However, some patients have intraarticular abnormalities causing insufficient coverage, containment or congruency after periacetabular osteotomy, or extraarticular abnormalities that limit either acetabular correction or hip motion. For these patients, we believe an additional proximal femoral osteotomy can improve coverage, containment, congruency and/or motion.

2010 International consensus algorithm for the diagnosis, therapy and management of hereditary angioedema

ABSTRACT:

Assessing the efficiency of a pharmacokinetic-based algorithm for target-controlled infusion of ketamine in ponies

The objective of this study was to assess a pharmacokinetic algorithm to predict ketamine plasma concentration and drive a target-controlled infusion (TCI) in ponies. Firstly, the algorithm was used to simulate the course of ketamine enantiomers plasma concentrations after the administration of an intravenous bolus in six ponies based on individual pharmacokinetic parameters obtained from a previous experiment. Using the same pharmacokinetic parameters, a TCI of S-ketamine was then performed over 120 min to maintain a concentration of 1 microg/mL in plasma. The actual plasma concentrations of S-ketamine were measured from arterial samples using capillary electrophoresis. The performance of the simulation for the administration of a single bolus was very good. During the TCI, the S-ketamine plasma concentrations were maintained within the limit of acceptance (wobble and divergence <20%) at a median of 79% (IQR, 71-90) of the peak concentration reached after the initial bolus. However, in three ponies the steady concentrations were significantly higher than targeted. It is hypothesized that an inaccurate estimation of the volume of the central compartment is partly responsible for that difference. The algorithm allowed good predictions for the single bolus administration and an appropriate maintenance of constant plasma concentrations.

Iterative Reconstruction Algorithm for Abdominal Multidetector CT at Different Tube Voltages: Assessment of Diagnostic Accuracy, Image Quality, and Radiation Dose in a Phantom Study

To assess the diagnostic accuracy, image quality, and radiation dose of an iterative reconstruction algorithm compared with a filtered back projection (FBP) algorithm for abdominal computed tomography (CT) at different tube voltages.

Low-tube-voltage, high-tube-current multidetector abdominal CT: improved image quality and decreased radiation dose with adaptive statistical iterative reconstruction algorithm--initial clinical experience

To investigate whether an adaptive statistical iterative reconstruction (ASIR) algorithm improves the image quality at low-tube-voltage (80-kVp), high-tube-current (675-mA) multidetector abdominal computed tomography (CT) during the late hepatic arterial phase.

Randomized clinical trial comparing percutaneous closure of patent foramen ovale (PFO) using the Amplatzer PFO Occluder with medical treatment in patients with cryptogenic embolism (PC-Trial): rationale and design

Background Several studies have shown an association of cryptogenic stroke and embolism with patent foramen ovale (PFO), but the question how to prevent further events in such patients is unresolved. Options include antithrombotic treatment with warfarin or antiplatelet agents or surgical or endovascular closure of the PFO. The PC-Trial was set up to compare endovascular closure and best medical treatment for prevention of recurrent events. Methods The PC-Trial is a randomized clinical trial comparing the efficacy of percutaneous closure of the PFO using the Amplatzer PFO occluder with best medical treatment in patients with cryptogenic embolism, i.e. mostly cryptogenic stroke. Warfarin for 6 months followed by antiplatelet agents is recommended as medical treatment. Randomization is stratified according to patients age (<45 versus ≥45 years), presence of atrial septal aneurysm (ASA yes or no) and number of embolic events before randomization (one versus more than one event). Primary endpoints are death, nonfatal stroke and peripheral embolism. Discussion patients were randomized in 29 centers of Europe, Canada, and Australia. Randomization started February 2000. Enrollment of 414 patients was completed in February 2009. All patients will be followed-up longitudinally. Follow-up is maintained until the last enrolled patient is beyond 2.5 years of follow-up (expected in 2011).

Infectiological, functional, and radiographic outcome after revision for prosthetic hip infection according to a strict algorithm

Successful treatment of prosthetic hip joint infection (PI) means elimination of infection and restored hip function. However, functional outcome is rarely studied. We analyzed the outcome of the strict use of a treatment algorithm for PI.