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RationaleTriage is crucial for patient’s management and estimation of the required Intensive Care Unit (ICU) beds is fundamental for Health Systems during the COVID-19 pandemic.ObjectiveTo assess whether chest Computed Tomography (CT) of COVID-19 pneumonia has an incremental role in predicting patient’s admission to ICU.MethodsWe performed volumetric and texture analysis of the areas of the affected lung in CT of 115 outpatients with COVID-19 infection presenting to the Emergency Room with dyspnea and unresponsive hypoxyemia. Admission blood laboratory including lymphocyte count, serum lactate dehydrogenase, D-dimer and C-Reactive Protein and the ratio between the arterial partial pressure of oxygen and inspired oxygen were collected. By calculating the areas under the receiver-operating characteristic curves (AUC), we compared the performance of blood laboratory-arterial gas analyses features alone and combined with the CT features in two hybrid models (Hybrid radiological and Hybrid radiomics)for predicting ICU admission. Following a machine learning approach, 63 patients were allocated to the training and 52 to the validation set.Measurements and Main ResultsTwenty-nine (25%) of patients were admitted to ICU. The Hybrid radiological model comprising the lung %consolidation performed significantly (p=0.04) better in predicting ICU admission in the validation (AUC=0.82; 95%Confidence Interval 0.68-0.95) set than the blood laboratory-arterial gas analyses features alone (AUC=0.71; 95%Confidence Interval 0.56-0.86). A risk calculator for ICU admission was derived and is available at:https://github.com/cgplab/covidappConclusionsThe volume of the consolidated lung in CT of patients with COVID-19 pneumonia has a mild but significant incremental value in predicting ICU admission.

In the context of the increasing spread of cardiac active implantable heart devices (CIEDs) in the population and of the wide diagnostic/therapeutic utility of magnetic resonance (MRI) examinations, the goal of this paper is to provide the experience of the Santa Maria Nuova Hospital of the USL Tuscany Center in Florence and to report an organizational proposal to perform, in the hospital settings, MRI examinations on patients carrying CIED. This report is intended to show the operational choices of a Radiology Department which organizes this activity in accordance with the new Italian regulatory framework in the field of safety of MR sites (Ministero della Salute in Decreto Ministeriale 10 agosto 2018 Determinazione degli standard di sicurezza e impiego per le apparecchiature a risonanza magnetica, 2018).

Purpose To propose an MRI quality assurance procedure that can be used for routine controls and multi-centre comparison of different MR-scanners for quantitative diffusion-weighted imaging (DWI). Materials and methods 44 MR-scanners with different field strengths (1 T, 1.5 T and 3 T) were included in the study. DWI acquisitions (b-value range 0–1000 s/mm2), with three different orthogonal diffusion gradient directions, were performed for each MR-scanner. All DWI acquisitions were performed by using a standard spherical plastic doped water phantom. Phantom solution ADC value and its dependence with temperature was measured using a DOSY sequence on a 600 MHz NMR spectrometer. Apparent diffusion coefficient (ADC) along each diffusion gradient direction and mean ADC were estimated, both at magnet isocentre and in six different position 50 mm away from isocentre, along positive and negative AP, RL and HF directions. Results A good agreement was found between the nominal and measured mean ADC at isocentre: more than 90% of mean ADC measurements were within 5% from the nominal value, and the highest deviation was 11.3%. Away from isocentre, the effect of the diffusion gradient direction on ADC estimation was larger than 5% in 47% of included scanners and a spatial non uniformity larger than 5% was reported in 13% of centres. Conclusion ADC accuracy and spatial uniformity can vary appreciably depending on MR scanner model, sequence implementation (i.e. gradient diffusion direction) and hardware characteristics. The DWI quality assurance protocol proposed in this study can be employed in order to assess the accuracy and spatial uniformity of estimated ADC values, in single- as well as multi-centre studies.

Purpose The AIFM working group on MR intercomparison has proposed a quality assurance protocol for MRI diffusion weighted imaging (DWI). The aim of this study is to test the accuracy of apparent diffusion coefficient (ADC) evaluation at the isocentre of the scanner. Methods Seventeen centres and twenty-six MRI scanners (20/6; 1.5 T/3.0 T) were enrolled in this study. A custom spherical water phantom (14 cm diameter, filled with doped aqueous solution) specifically designed for DWI QA was provided to all participants. ADC value was certified as in [1] . Phantom was placed at isocentre of scanner. 5 mm thick axial slices at the isocentre were acquired, using three DWI sequences (b-value varying form 0 s/mm2 to 1000 s/mm2 at 200 s/mm2 steps), differing in gradient diffusion direction. For each diffusion direction, ADC image was generated with monoexponential fit and corrected for temperature. Analysis was performed with a custom Matlab software code. Average ADC was calculated for each diffusion direction ( ADC x , ADC y , ADC z ) in a 2 × 2 cm2 ROI at the centre of the phantom. A chi-squared consistency test was performed on the three ADC values. The mean value ( ADC ref ) was compared with the certified ADC C value. Results Differences within ADC x,y,z are less than 1.5%, for 21 scanners. For seven scanners ADC x,y,z were not consistent among themselves. ( ADC ref / ADC C - 1 ) vary from +10% to −7% (mean value −1%). Only in four scanners | ( ADC ref / ADC C - 1 ) | is larger than 5%. Conclusions The proposed protocol and multipurpose phantom provide a simple ADC quality assurance procedure. The measured isocentre ADCs are within 1% with reference to wrt diffusion directions and consistent with certified value within 1%.

Purpose The recent publication “Supplement to European Guidelines”, version 1.0, 2013, (S1), has reviewed the tests for quality assurance of digital mammographic equipment. The majority of the tests considered as essential or desirable regard the detector and the resulting quality of the images. The analyses are very demanding if no suitable tools for the automatic analysis of the images are available. The authors developed a free prototype of such a tool to be improved with the practise and the feedbacks of the possible users. Methods MaMMoS1 is a homemade software for analyzing mammographic digital images. It was written in MATLAB® but it does not require Matlab installed on the computer. It was developed at our facilities for helping us in our routine quality controls. In the intention of the authors it would be a starting platform that should be improved by feedback and suggestions from the users. Currently it performs the following test-items described in S1: (Essential) 2b.2.2.1.1 Response function/2b.2.2.1.2 Noise evaluation. 2b.2.1.3.5 AEC Breast thickness and composition compensation. 2b.2.2.3.1 Image receptor homogeneity. 2b.2.4.5 Ghost image/erasure thoroughness. (Desirable) 2b.2.1.3.6 Local dense area. It can be downloaded at: https://www.fisicamedica.it/gruppi/gruppo-regionale/toscana . Instructions for the installation and use of the software are given in a readme file. Results The software has been routinely applied proving useful for the calculation of the requested parameters. Each test requires no more than a few seconds. It is possible to process images on site and so it is possible to identify defective performance soon after the measurements, possibly apply corrective procedures and repeat the test. Conclusions The introduction of MaMMoS1 in our quality assurance program has allowed economic and human resources savings as a considerable amount of time during each check can be saved. It can be updated to include additional analysis and tools to make the quality checks faster and easier for the user. The detector performances, homogeneity, response function, ghost, and noise, can be fully explored so the software can be used for digital detector of other modalities with respect to mammography an in the future include additional more specific features. Download : Download high-res image (208KB) Download : Download full-size image

Purpose The dependence of ADC (measured in isotropic phantom) on position and ADC phase encoding may be used to test MRI scanner performances and may play relevant effect on quantitative data accuracy in clinical imaging. Quantitative results of AIFM multicentre intercomparison are reported. Methods Twenty-six MR scanners (20/6 1.5 T/3.0 T magnetic field strength) were enrolled in this study. Custom spherical water phantom (14 cm diameter) specifically designed for DWI QA was provided to all participants. ADC value was certified as in [1] . Phantom was placed at isocentre of scanner. Using three DWI sequences (b-value varying form 0 s/mm2 to 1000 s/mm2), differing for the gradient diffusion direction (Gdd), 5 mm thick axial slices were acquired (5 mm gap). Acquisition was repeated exchanging frequency and phase encoding direction. ADC maps were generated for each Gdd. Seven 2 × 2 cm2 ROIs were considered: one at isocentre and six in periphery (left, right, superior, inferior, head and feet). For each acquisition, maximum relative difference between periphery and central ROIs ADC was calculated ( δ ADC % x,y,z ) . Maximum δ ADC % x,y,z with respect to three acquisitions ( δ M%) was also considered. As for phase/frequency encoding direction dependences, ADC x,y,z differences on central ROI were measured. Results Differences Absolute value of δ M is below 5% for 19 scanners, 18 scanners show δ M > 0. Spatial direction of maximal variation is “x” in 23 scanners, “y” in the other. Gdd associated to δ M is x/y/z for 9/12/5 scanners. Differences between −2% and +1% have been observed with respect to phase encoding direction. Conclusions A simple protocol for quantitative evaluation of ADC spatial and phase encoding dependence has been proposed. Difference in ADC between isocentre and periphery should be consider in precision ADC measurements.

Purpose Aim of this work was to use the dose index information from 5 mammography units within USL Toscana Centro, Firenze-Empoli area, analysing and comparing the compression force data and the AGD trend with the thickness of the compressed breast. Methods The RDMI data from Siemens Mammomat Inspiration mammography units were analysed by exploiting the information gathered in a local LOG file that records all the exposure parameters of each single shot. Data in the file are extracted in a spreadsheet tool. All the devices have the same kV-breast thickness compensation curve and work in AEC mode with a W/Rh combination. For the analysis, we focused on data for the year 2015–2016 covering about 40,000 patients for a total of over 169,200 projections. Data are filtered eliminating quality test and manual exposures, breast implants and surgical pieces. Results The average compression force values, for the year 2015, are similar in the first 4 unit. For the Unit 5, it’s found that the breast is significantly less compressed. After a training session on the correct use of the compression paddle, data for year 2016 were analysed. Since then, there are comparable forces with other devices. Nevertheless, for all mammography, there is a very large compression range, with maximum points greater than 200 N and values at the lower limit of 20 N. For the analysis of AGD vs thickness, all devices fall within the EUREF limit values (see Table). Conclusions Data collection has allowed to investigate and compare retrospectively all exams executed in the year 2015 −2016, evaluate anomalies not highlighted with quality assurance tests and take corrective actions to improve performance. Download : Download high-res image (128KB) Download : Download full-size image

Purpose To propose a magnetic resonance imaging (MRI) quality assurance procedure that can be used for multicenter comparison of different MR scanners for quantitative diffusion-weighted imaging (DWI). Materials and Methods Twenty-six centers (35 MR scanners with field strengths: 1T, 1.5T, and 3T) were enrolled in the study. Two different DWI acquisition series (b-value ranges 0–1000 and 0–3000 s/mm2, respectively) were performed for each MR scanner. All DWI acquisitions were performed by using a cylindrical doped water phantom. Mean apparent diffusion coefficient (ADC) values as well as ADC values along each of the three main orthogonal directions of the diffusion gradients (x, y, and z) were calculated. Short-term repeatability of ADC measurement was evaluated for 26 MR scanners. Results A good agreement was found between the nominal and measured mean ADC over all the centers. More than 80% of mean ADC measurements were within 5% from the nominal value, and the highest deviation and overall standard deviation were 9.3% and 3.5%, respectively. Short-term repeatability of ADC measurement was found

The aim of this study was to assess the patient dosimetric impact of endovascular abdominal aortic aneurysm repair (EVAR), both in an operating theatre (OR) and in an angiosuite (AS), with the facility of Dynamic CT (Dyna CT, Siemens AG, Berlin, Germany). One hundred and forty-six consecutive EVAR procedures dating from May 2011 to March 2013 were analysed. These were performed either in an OR (n = 97) using a mobile C-arm or in an AS (n = 49) equipped with a ceiling-mounted angiography system. Air kerma area product (P(KA)) and total air kerma at reference point (K(a,r)) values were reported for all procedures and Dyna CT. Radiation exposure during EVAR was quite low in the majority of patients but nearly 50 % higher if performed in AS vs. OR. Median Dyna CT K(a,r) was the same as an entire EVAR procedure in OR. The higher patient's radiation exposure recorded in the AS should be balanced with the technical advantages given to the EVAR procedure.

Background Adult-type hypolactasia is a widespread condition throughout the world, causing lactose malabsorption. The lactose breath test is a simple tool for diagnosis but the need for prolonged monitoring of hydrogen excretion has led to a genetic test proposal. The aim of this study was to compare the genetic test with the lactose breath test in order to give some insights into the clinical value of genetic testing. Methods Thirty-two consecutive functional patients underwent lactose breath test and lactase genetic polymorphism analysis (C/T 13910 and G/A 22018). Intolerance symptoms after lactose load were also monitored. Results All patients with positive lactose breath test showed homozygosis for both polymorphisms. Among the nine patients with a negative breath test result, six showed heterozygosis while three showed homozygosis. Intolerance symptoms were present in 16 homozygotic patients but also in one heterozygotic patient. The k value for the agreement between the genetic test and the lactose breath test was 0.74. Conclusion A positive genetic test for lactase non-persistence indicates whether lactase activity decline may represent a clinical problem for the patient, but does not give information on actual patient symptoms. On the contrary, this information is already available by combining the lactose breath test with intolerance symptom evaluation. Lactose absorption phenotype may be not yet evident until young adult age.

In irritable bowel syndrome (IBS), the modulation of neural pathways may be altered and we have recently shown that postprandial recto-sigmoid tone modification is impaired. On pathophysiological grounds, we do not know whether this alteration may have a role in symptom onset and, in particular, whether an effective drug, such as tegaserod, can improve this response together with symptom severity.Twenty-two female patients with constipation-predominant IBS (IBS-C), diagnosed according to Rome II criteria, were studied. All subjects underwent an evaluation of the presence and severity of IBS symptoms and the recto-sigmoid barostat test to measure fasting and postprandial recto-sigmoid tone and phasic contractility. They were then randomly assigned to receive either tegaserod 6 mg b.i.d (12 patients) or placebo tablets (10 patients) for 4 wk, according to a double-blind protocol. Symptom assessment and recto-sigmoid tone and contractility were re-evaluated at the end of the treatment.Both symptom severity and postprandial modification of recto-sigmoid tone improved only in the tegaserod group and a significant correlation was evident between the improvement of bloating and the improvement of postprandial recto-sigmoid tone modification. No effect of tegaserod on recto-sigmoid motility index or correlation between motility index and symptom improvement was evident.In IBS-C female patients, the administration of tegaserod improves symptom severity and is accompanied by an improvement of recto-sigmoid tone response to a meal.

Summary Dendritic cells (DC) play a pivotal role in shaping the immune response in both physiological and pathological conditions. In peripheral blood at least two subsets, the myeloid and plasmacytoid, have been described as having different T stimulatory functions and a variable degree of maturation. Certainly, antigen presentation plays a crucial role in the pathogenesis of coeliac disease and circulating immune cells are thought to reflect the state of immune response within the gut. Therefore, we aimed to investigate the quantitative and phenotypical modifications of peripheral blood DC, together with their functional properties, in this pathological condition. Blood samples from 11 untreated patients before and after a course of gluten-free diet, 27 treated patients and 14 controls underwent flow-cytometric analysis, while immunomagnetically sorted DC from the CD patients and eight human leucocyte antigen (HLA)-DQ2/8+ bone marrow donors were used to evaluate maturation status through the CD83 expression, cytokine profile for interleukin (IL)-6, IL-10, IL-12 and interferon (IFN)-α by enzyme-linked immunosorbent assay (ELISA), and functional properties by mixed leucocyte reaction before and after pulsing with digested gliadin. We found that in both untreated and treated patients, a significant reduction of the entire DC population, mainly the plasmacytoid subset, in comparison to healthy controls was observed. In active disease, an impaired allogenic lymphocyte reaction and a significant reduction of IFN-α production, paralleled by the presence of a more immature status, were also demonstrated. All the latter modifications have been reverted by pulsing DC with digested gliadin.

Bloating, abdominal distention, and flatulence represent very frequent complaints in functional disorders but their pathophysiology and treatment are largely unknown. Patients frequently associate these symptoms with excessive intestinal gas and the reduction of gas production may represent an effective strategy. The aim was to evaluate the effect of alpha-galactosidase administration, in a randomized double-blind placebo-controlled protocol, on intestinal gas production and gas-related symptoms after a challenge test meal in healthy volunteers. Eight healthy volunteers ingested 300 or 1200 GalU of alpha-galactosidase or placebo during a test meal containing 420 g of cooked beans. Breath hydrogen excretion and occurrence of bloating, abdominal pain, discomfort, flatulence, and diarrhea were measured for 8 hr. The administration of 1200 GalU of alpha-galactosidase induced a significant reduction of both breath hydrogen excretion and severity of flatulence. A reduction in severity was apparent for all considered symptoms, but both 300 and 1200 GalU induced a significant reduction in the total symptom score. Alpha-galactosidase reduced gas production following a meal rich in fermentable carbohydrates and may be helpful in patients with gas-related symptoms.

Background and aims: Diagnosis of irritable bowel syndrome (IBS) is based on arbitrary criteria due to the lack of an accurate diagnostic test. The aim of this study was to evaluate whether rectosigmoid tone modification after a meal represents an accurate diagnostic approach. Methods: In a secondary care setting, 32 constipation predominant and 24 diarrhoea predominant IBS patients, 10 functional diarrhoea and 10 functional constipation patients, 29 organic gastrointestinal disease patients, and 10 healthy volunteers underwent a rectal barostat test to measure fasting and postprandial rectosigmoid tone. Rectosigmoid response was assessed following three meals containing different amounts of calories: 200 kcal, 400 kcal and 1000 kcal. Results: After 200 kcal, healthy volunteers and patients with organic diseases showed a reduction in rectosigmoid volume of at least 28% of fasting volume, indicating a meal induced increase in muscle tone. In contrast, patients with diarrhoea predominant IBS showed dilation of the rectosigmoid colon, indicative of reduced tone, and patients with constipation predominant IBS showed a mild volume reduction or no modification. Functional diarrhoea and constipation patients showed rectosigmoid tone modification resembling that of the corresponding IBS subtype. A 400 kcal meal normalised rectosigmoid tone in more than half of the constipation predominant IBS patients but none of the diarrhoea predominant IBS patients. In contrast, a 1000 kcal meal normalised tone response in all IBS patients. Sensitivity of the test was 100%, specificity 93%, positive predictive value 96%, and negative predictive value 100%. Conclusion: A postprandial reduction in rectosigmoid tone of at least 28% of fasting value after a low caloric meal accurately separates organic and functional gastrointestinal disease patients. This parameter may therefore be used in the positive diagnosis of IBS.

The aim of this work was to test the suitability of a PTW diamond detector for nonreference condition dosimetry in photon beams of different energy (6 and 25 MV) and field size (from 2.6 cm x 2.6 cm to 10 cm x 10 cm). Diamond behavior was compared to that of a Scanditronix p-type silicon diode and a Scanditronix RK ionization chamber. Measurements included output factors (OF). percentage depth doses (PDD) and dose profiles. OFs measured with diamond detector agreed within 1% with those measured with diode and RK chamber. Only at 25 MV, for the smallest field size, RK chamber underestimated OFs due to averaging effects in a pointed shaped beam profile. Agreement was found between PDDs measured with diamond detector and RK chamber for both 6 MV and 25 MV photons and down to 5 cm x 5 cm field size. For the 2.6 cm x 2.6 cm field size, at 25 MV, RK chamber underestimated doses at shallow depth and the difference progressively went to zero in the distal region. PDD curves measured with silicon diode and diamond detector agreed well for the 25 MV beam at all the field sizes. Conversely, the nontissue equivalence of silicon led, for the 6 MV beam, to a slight overestimation of the diode doses in the distal region, at all the field sizes. Penumbra and field width measurements gave values in agreement for all the detectors but with a systematic overestimate by RK measurements. The results obtained confirm that ion chamber is not a suitable detector when high spatial resolution is required. On the other hand, the small differences in the studied parameters, between diamond and silicon systems, do not lead to a significant advantage in the use of diamond detector for routine clinical dosimetry.

The dosimetric properties of two PTW Riga diamond detectors type 60003 were studied in high-energy photon and electron therapy beam. Properties under study were current-voltage characteristic, polarization effect, time stability of response, dose response, dose-rate dependence, temperature stability, and beam quality dependence of the sensitivity factor. Differences were shown between the two detectors for most of the previous properties. Also, the observed behavior was, to some extent, different from what was reported in the PTW technical specifications. The necessity to characterize each diamond detector individually was addressed.

The thermoluminescence (TL) characteristics of a set of six chemical vapour deposited diamond films have been studied with regard to their use as off-line dosimeters in radiotherapy. The structural characterisation has been performed by means of Raman spectroscopy. Their TL responses have been tested with radiotherapy beams ( 60 Co photons, photons and electrons from a linear accelerator (Linac), 26 MeV protons from a TANDEM accelerator) in the dose range 0.1–7 Gy. The dosimetric characterisation has yielded a very good reproducibility, a very low dependence of the TL response on the type of particle and independence of the radiation energy. The TL signal is not influenced by the dose rate and exhibits a very low thermal fading. Moreover, the sensitivity of the diamond samples compares favourably with that of standard TLD100 dosimeters.

In this work, the dose response of TLD-100 dosimeters has been studied in a 62 MeV clinical proton beams. The signal versus dose curve has been compared with the one measured in a 60 Co beam. Different experiments have been performed in order to observe the thermal stress and the radiation damage effects on the detector sensitivity. A LET dependence of the TL response has been observed. In order to get a physical interpretation of these effects, a computerised glow-curve deconvolution has been employed. The results of all the performed experiments and deconvolutions are extensively reported, and the TLD-100 possible fields of application in the clinical proton dosimetry are discussed.

The high sensitivity and the nearly tissue equivalence of diamond make it a material suitable as detector for on-line dosimetry. The tremendous development of the CVD diamond technology allows to employ polycrystalline diamond films with controlled dimensions and a potential low cost as on-line radiation dosimeters. In this paper a characterisation and a comparison of the response of two “detector-grade” CVD diamond films under photon and electron beams are presented. The results show that both samples can be used as on-line dosimeters for applications in radiotherapy.

CVD diamond films have been irradiated with electrons, 60 Co photons and protons in order to study the dose response to exposure to different particles and energies and to investigate linearity with dose. The Thermally Stimulated Current (TSC) has been studied as a function of the dose delivered to polymethilmetacrilate (PMMA) in the range from 1 to 12 Gy with 20 MeV electrons from a linear accelerator. The TSC spectrum has revealed the presence of two components with peak temperatures of about 470 and 520 K, corresponding to levels lying in the diamond band gap with activation energies of the order of 0.7 – 1 eV. After the subtraction of the exponential background the charge emitted during the heating scan has been evaluated and has been found to depend linearly on the dose. The thermally emitted charge of the CVD diamond films has also been studied using different particles. The samples have been irradiated with the same PMMA dose of about 2 Gy with 6 and 20 MeV electrons from a Linac, 60 Co photons and 21 MeV protons from a TANDEM accelerator. A similar TSC response has been found at different irradiation conditions.

In this paper, Signal integrity (SI) analysis is used to analyze effect of crosstalk on performance of a High Speed Digital Module: its most critical part is simulated by ADS, a simulation tool, and then it is measured by an oscilloscope to verify the correctness of results. Technology trends toward higher speed and device density have increased complexity of PCB design to support fast varying and broadband signals without degrading the SI to unacceptable levels. The SI analysis relies on time-domain simulation of pseudo-random data patterns with at rates about 1 Gb/s. The models, like IBIS and SPICE, are required to describe the electrical behavior of the integrated components involved at interconnect traces. This paper is focused on crosstalk, which is one of the main issues of concern for SI. The final result validation is important to define the limitation of simulation for the pre- and post- layouts of electronic board and to reduce the design risk.

Introduction Radiation Dose Index Monitoring (RDIM) are useful software tools that allow radiological data collection and patient dose monitoring. However its implementation need a thorough acceptance test. Purpose Aim of this work is to test the consistency of data processed by two RDIM software and use the dose index information archived to optimize radiological procedures in our hospitals. Materials and methods We began in 2012 to monitor dose index data from 7 CTs and 2 angiographic units using CareAnalytics (CA) tool by Siemens. CA processes DICOM RDSR stored in PACS. Moreover within an Italian project, RDM by Medsquare has been tested since Gen 2015. RDM collects and analyzes doses delivered to patients during medical imaging examinations. One mammographic installation, 2 CTs and 1 angiographic unit has been connected to RDM. Results For angiographic procedure we have compared the maximum incident air kerma at the reference point at different times and at different C arm positions with the dose values obtained by softwares. For mammography, data from header DICOM have been positively compared with RDM data. For CT we have compared values obtained from console, CA and RDM. Conclusion In our experiences both the software under test seems to be useful tools to monitor radiation dose index. RDM allows wider applications and custom made options. Disclosure Nothing to declare.

Introduction Patient-specific pre-treatment quality assurance (QA) is a necessary prerequisite to VMAT treatment. 2D detector arrays have become the standard device for verification of intensity modulated dose distributions. Purpose Aim of this work is to verify the suitability of two ionization chamber 2D arrays (PTW Octavius4D 1500 and PTW Octavius4D 729) for pre-treatment VMAT plan verification and to compare the results achieved by the two systems. Materials and methods Measurements were performed by Octavius4D 1500 and Octavius4D 729 in the Octavius4D phantom. Forty VMAT plans elaborated by TPS Elekta Monaco ® 5.0 and delivered by Elekta Synergy ® Linac (6, 10 MV) have been used in this study (10 head and neck, 10 breast, 10 prostate and 10 pelvic treatments). 3D gamma metric at 3% L/3 mm has been used to compare measured and computed maps. Results Mean gamma pass rate for the Octavius4D 1500 was 93.9% (s.d. 3.5%) for HN plans, 95.6% (s.d. 2.4%) for breast treatments, 98.9% (s.d. 1.7%) for prostate and 95.6% (s.d. 2.2%) for pelvic plans. Mean gamma pass rate for the Octavius4D 729 was 92.4% (s.d. 4.9%) for HN plans, 80.7% (s.d. 11.9%) for breast treatments, 97.8% (s.d. 5.1%) for prostate and 87.6% (s.d. 4.3%) for pelvic plans. Improve measurement resolution by merging two longitudinally shifted measurements resulted in a better agreement between measured and computed maps for both dosimetric devices. Conclusion Both investigated systems resulted suitable for VMAT pre-treatment QA, but Octavius 4D 1500 outperformed its predecessor Octavius4D 729 because of the higher spatial resolution of the dosimeters.

The European Council Directive 97/43 introduces diagnostic reference levels (DRL) for all medical examinations involving ionising radiation. Each department has to evaluate patient dose and to compare that value with the DRL adopted by its member state. Italian law, applying the Directive, states that reference levels must be measured every 2 years. Quantities that must be measured are entrance surface dose or air kerma, or other dosimetric quantities. In our work, clinical measurements on patients were made by positioning a thermoluminescence dosemeter (TLD) over the skin of a statistically significant number of patients for each projection of each examination. As there is no national guideline for these measurements in Italy, the aim of this work was to establish a method based both on European publications and on clinical experience. Three different modalities were considered: conventional radiography, computed radiography and mammography. Accordingly, differently shaped types of TLD were required, especially for mammography where the beam energy is lower.

Background & Aims: Bloating represents a frequent gastrointestinal symptom, but the pathophysiologic mechanism responsible for its onset is still largely unknown. Patients very frequently attribute the sensation of bloating to the presence of excessive bowel gas, but not all patients with gas-related symptoms exhibit increased intestinal production of gas. It is therefore possible that other still unrecognized mechanisms might contribute to its pathophysiology. Our aim was to evaluate whether a subgroup of patients affected by functional abdominal bloating presents hypersensitivity to colonic fermentation. Methods Sixty patients affected by functional gastrointestinal disorders (11 functional bloating, 36 constipation-predominant, and 13 diarrhea-predominant irritable bowel syndrome) and moderate to severe bloating took part in the study. Twenty sex- and age-matched healthy volunteers were enrolled as a control group. All the subjects underwent a preliminary evaluation of breath hydrogen excretion after oral lactulose. Then, on a separate day, an evaluation of sensitivity thresholds at rectal level was performed with a barostat before and after the induction of colonic fermentation with oral lactulose. A control test with electrolyte solution was also performed. Results Both breath hydrogen excretion and mouth-to-cecum transit time did not differ between the 4 groups studied. Neither electrolyte solution nor lactulose modified sensitivity thresholds in healthy volunteers. In low hydrogen producers, basal perception and discomfort thresholds were similar to high hydrogen producers, but after lactulose both perception and discomfort thresholds were significantly reduced only in low hydrogen producers. Conclusions A subgroup of patients with functional gastrointestinal disorders and moderate to severe bloating might have hypersensitivity to products of colonic fermentation.

Phototimer set-up is a critical procedure for dose and image quality optimisation in computed radiography (CR) systems. While a conventional radiography automatic exposure control device (AEC) can be calibrated in order to gain a constant optical density on the film independent of beam quality and patient size, CR detectors present a high dynamic range which allows a much larger dose interval, but with different image quality levels. CR leads to a less frequent exam repetition, but may produce quite noisy images if the exposure level on the plate is not correct. The aim of this work is to evaluate the performance of a CR plate (Agfa MD40) in order to optimally calibrate an AEC device. The plate response has been characterised in terms of digital signal, exposure on the plate and signal-to-noise ratio for different beam qualities, in a patient of standard size.

The pathophysiology of functional dyspepsia is not yet completely known. Several mechanisms have been suggested as having a role in symptom onset and impaired gastric accommodation to meal is one of the most frequent. This review will focus on the pathophysiological and clinical aspects of this abnormality.Medical peer-reviewed literature was considered to elucidate the role of gastric accommodation in the pathophysiology of functional dyspepsia.Impaired gastric accommodation to meal is present in around 40% of patients with functional dyspepsia and it was shown to be associated with the presence of early satiety. Unfortunately, a definitive treatment of this abnormality with fundus-relaxing drugs is not yet available.Further studies are needed to better clarify the role of each single pathophysiological mechanism on clinical manifestations of functional dyspepsia. Research is still ongoing to offer a valid therapeutic approach.

Background Small intestine bacterial overgrowth is associated with the presence of predisposing conditions, acting through different mechanisms. Therefore, the failure to define a standardized therapy may be due to a methodological bias: to treat a condition characterized by different pathophysiological mechanisms with the same pharmacological approach. Non-absorbable antibiotics could have a lower efficacy than absorbable drugs in patients with blind loops which exclude a portion of the intestine from the transit. Aim To evaluate the efficacy of absorbable vs. non-absorbable antibiotics in this subgroup of patients. Methods A group of small intestine bacterial overgrowth patients with total gastrectomy or gastrojejunostomy and blind loop underwent a therapeutic trial comparing rifaximin to metronidazole. Seven patients underwent a course of rifaximin followed by a course of metronidazole on recurrence of symptoms. To compare the effect of the drugs, another two groups of patients underwent two consecutive courses of rifaximin or metronidazole. Hydrogen breath test after glucose administration and symptom severity measurement were performed. Results Both drugs reduced breath H(2) excretion but a much better improvement was achieved after metronidazole. Symptom improvement was higher after metronidazole. Conclusion Metronidazole is more effective than rifaximin for the treatment of small intestine bacterial overgrowth associated with the presence of a blind loop.

The possibility of using CVD diamond films as dosimeters in radiotherapy applications has been tested in both off-line and on-line configurations. The thermoluminescent and thermally stimulated current responses after 20 MeV electron and 22 MeV proton irradiation have been studied as a function of the dose up to 10 Gy. CVD diamond compares favourably with standard off-line LiF dosimeters. In the on-line configuration, detector-grade high-purity CVD diamond shows a sensitivity almost four order of magnitude higher than that of ionisation chambers.

The aim of this work was to investigate the use of TLD-100 detectors in the field of relative dosimetry in proton eye facilities. These dosemeters, of different sizes, were used to measure transverse and longitudinal distributions of 62 MeV unmodulated proton beams at INFN-LNS in Catania. Comparison with other detectors, such as ionisation chambers, GAF and radiographic film, is extensively discussed.

The necessity to develop methods and techniques for a better determination of absorbed dose in the radiotherapy field stimulates new clinical applications of solid state detectors. In this work we have studied the possibility to use of TLD-100 and synthetic CVD diamond detectors as dosimeters for high-energy proton beams.