Un rivelatore innovativo per gamma imaging tridimensionale

Il gamma imaging in medicina nucleare è un insieme di tecniche che permette di ottenere immagini dalla rivelazione di fotoni gamma emessi dai radionuclidi usati in questo ambito. Queste tecniche prevedono l'utilizzo di rivelatori composti da cristalli scintillanti letti da fotomoltiplicatori sensibili alla posizione, come i Position Sensitive – Photomultiplier Tube (PS-PMT). Un'alternativa ai PS-PMT è rappresentata da fotomoltiplicatori a semiconduttore, denominati Silicon Photomultiplier (SiPM). Questi hanno lo stesso guadagno dei PS-PMT (~106) che comporta un ottimo rapporto segnale rumore, ma sono più compatti, insensibili ai campi magnetici ed hanno una risposta molto veloce (~30ps), che li rende ideali in tecniche in cui è necessario conoscere con precisione l'informazione temporale dell'evento. In questo lavoro ho contribuito alla messa a punto e alla caratterizzazione di un rivelatore innovativo per gamma imaging con elevate prestazioni in termini di risoluzione spaziale in tre dimensioni. Il particolare disegno adottato per la rivelazione dei fotoni consente di ottenere informazioni sulla profondità di interazione (Depth Of Interaction - DOI), migliorando così la precisione complessiva del dispositivo di imaging. Il rivelatore proposto è costituito da un cristallo scintillatore di LYSO con pareti laterali nere di dimensioni 2 cm x 2 cm x 1 cm letto sulle superfici maggiori da matrici di SiPM, ciascuna costituita da 4x4 SiPM di 4 mm x 4 mm; il segnale da essi registrato viene letto e processato da circuiti integrati ed inviato ad un computer. Il sistema è stato caratterizzato tramite un fascio collimato (Ø 1 mm)di fotoni da 511 keV emessi da una sorgente di Na 22. Le facce del cristallo sono state scansionate tramite un sistema di traslatori gestiti da computer per ottenere le informazioni spaziali tridimensionali. La posizione di interazione sul piano dei fotorivelatori (piano X-Y) è stata ottenuta usando la logica di Anger, che si basa sulla media pesata dei segnali in carica generati dai SiPM. L'informazione relativa alla DOI (coordinata Z) è stata ottenuta usando la formula dove D è lo spessore del cristallo, mentre NT1 ed NT2 sono rispettivamente il numero di SiPM che hanno registrato un segnale nelle superfici superiore ed inferiore. I risultati ottenuti mostrano che il dispositivo ha una risoluzione spaziale di circa 2 mm (FWHM) sul piano dei fotorivelatori. È stato inoltre dimostrato che è possibile ottenere informazioni relative alla profondità di interazione tramite la formula descritta in precedenza. Questa tecnica dà risultati in accordo con le posizioni del fascio, anche se l'incertezza è elevata. Tuttavia il rivelatore proposto è un prototipo, ed i risultati ottenuti sono soggetti a limitazioni geometriche. È infatti in fase di realizzazione un ulteriore prototipo in cui è previsto l'uso di matrici di SiPM con pixel di dimensioni inferiori, che migliora la risoluzione spaziale sul piano X-Y e la stima della DOI, e cristalli più grandi per diminuire gli effetti di bordo

Burnout and engagement dimensions in the reception system of illegal immigration in the Mediterranean Sea. A qualitative study on a sample of italian practitioners

The present study describes the semantic nature of burnout and engagement in the operators involved in the management of illegal immigration. Semi-structured interviews were conducted on a sample of Italian practitioners (n = 62) of the two levels of the reception system considered: (1) rescue and first aid and (2) reception and integration. Within the framework of the job demands–resources model (JD-R), the interviews deepened the analysis of the positive and negative dimensions of burnout and engagement: exhaustion versus energy, relational deterioration versus relational involvement, professional inefficacy versus professional efficacy and disillusion versus trust. The interviews were analysed using the T-Lab software, through a cluster analysis (bisecting K-means algorithm), which emphasised noteworthy themes. The results show that, in the vast majority of the dimensions considered (for both levels of reception), the same dimensions of engagement of the operators (energy, relational involvement, professional efficacy and trust) are able to lead them into a condition of burnout, with experiences, conversely, of exhaustion, relational deterioration, professional inefficacy and disillusion. These findings expand the knowledge on burnout and engagement in practitioners of illegal immigration, a context characterised by the value of help and welcome

Three-dimensional geometrical models of the inguinal region. Towards a new stereology

In this work we studied the inguinal-abdominal region and the inguinal canal using three-dimensional geometrical models. We built the models through computer aided geometric modeling techniques on the basis of observations during real dissections, operations and diagnostic medical imaging. The obtained models show in a complete modular synthesis and with a schematic iconology the structural organization of the anatomical districts in a logic sequence of layers and topographic and spatial relationships among its components. The models represent an amazing support to anatomy and clinical anatomy for teaching and research purposes on organogenesis, surgery and diagnosis

Pyoderma gangrenosum of the “sinus mammarum” in ulcerative colitis

The first part of this article deals with the report of a patient suffe - ring from pyoderma gangrenosum of the “sinus mammarum” associa - ted with asymptomatic ulcerative colitis. This is followed by a revision of the present epidemiological, etiological, pathogenetic and clinical knowledges about this systemic manifestation of chronic phlogosis of the colon. The Authors have analysed the treatment for this condition and emphasized the resistance of the cutaneous ulcer encountered to conven - tional medical therapy of the underlying colonic disease which proved to be efficacious only on the latter; this led to integrate traditional treatment with the use of perilesional injections of small doses of calcic heparin as an alternative to immunosuppressive drugs or surgery. Topical antithrombotic treatment, which can be justified by the histo - logical findings of phenomena of the vasculitis in the edge of pyoderma gangrenosum, demonstrated to be crucial and represents a peculiarity in the case here reported, which is unique in the literature as far as the Authors know, since it has not been experimented by anyone else

A pilot study about on-farm assessment of health and welfare in rabbits kept in different housing systems

This pilot study tested an on-farm protocol based on resource, management, and animal-based measures to evaluate the on-farm health and welfare of rabbits kept in four different housing systems. In detail, the four housing systems were (1) standard breeding cages for reproducing does (3,300 cm2) with their litters associated with bicellular cages for growing rabbits (1,200 cm2); (2) dual-purpose cages for both reproducing does and growing rabbits (3,655 cm2); (3) enriched cages (4,739 cm2) for both reproducing does and growing rabbits equipped with a wire-mesh elevated platform (1,015 cm2); (4) parks (30,977 cm2) made up of four modules (7,744 cm2 each) joined by removing the wire net walls between them with growing rabbits kept in collective parks and reproducing does individually in the single modules. A total of 12 commercial farms (three farms/four housing systems) were visited during three seasons (summer, autumn, and winter) on two occasions each: (1) a pre-weaning visit for recordings on reproducing does and litters and (2) a pre-slaughtering visit for recordings on growing rabbits. At the pre-weaning visit, the prevalence of health concerns did not differ among does and litters kept in the different housing systems. At the pre-slaughtering visit, a higher prevalence of dermatomycosis was found in farms with dual-purpose cages and parks. Overall, taking into account the limitations due to the small sample size per housing system and the field conditions, the on-farm assessment tested in the present pilot study did not highlight major differences in the welfare and health of reproducing does and their kits as well as of growing rabbits in farms using different housing systems, which need to be confirmed on a large number of farms. The study also outlined the role of several management and environmental factors changing from one farm to another, which stresses the troubles of accounting for on-farm rabbit welfare and health exclusively to the housing system.info:eu-repo/semantics/publishedVersio

Full-beam performances of a PET detector with synchrotron therapeutic proton beams

Treatment quality assessment is a crucial feature for both present and nextgeneration ion therapy facilities. Several approaches are being explored, based on prompt radiation emission or on PET signals by β+;-decaying isotopes generated by beam interactions with the body. In-beam PET monitoring at synchrotron-based ion therapy facilities has already been performed, either based on inter-spill data only, to avoid the influence of the prompt radiation, or including both in-spill and inter-spill data. However, the PET images either suffer of poor statistics (inter-spill) or are more influenced by the background induced by prompt radiation (in-spill). Both those problems are expected to worsen for accelerators with improved duty cycle where the inter-spill interval is reduced to shorten the treatment time. With the aim of assessing the detector performance and developing techniques for background reduction, a test of an in-beam PET detector prototype was performed at the CNAO synchrotron-based ion therapy facility in full-beam acquisition modality. Data taken with proton beams impinging on PMMA phantoms showed the system acquisition capability and the resulting activity distribution, separately reconstructed for the in-spill and the inter-spill data. The coincidence time resolution for in-spill and inter-spill data shows a good agreement, with a slight deterioration during the spill. The data selection technique allows the identification and rejection of most of the background originated during the beam delivery. The activity range difference between two different proton beam energies (68 and 72 MeV) was measured and found to be in submillimeter agreement with the expected result. However, a slightly longer (2 mm) absolute profile length is obtained for in-spill data when compared to inter-spill data

GDNA qPCR is statistically more reliable than mRNA analysis in detecting leukemic cells to monitor CML

Chronic Myeloid Leukemia (CML) is a stem cell cancer that arises when t(9;22) translocation occurs in a hematopoietic stem cells. This event results in the expression of the BCR-ABL1 fusion gene, which codes for a constitutively active tyrosine kinase that is responsible for the transformation of a HSC into a CML stem cell, which then gives rise to a clonal myeloproliferative disease. The introduction of Tyrosine Kinase Inhibitors (TKIs) has revolutionized the management of the disease. However, these drugs do not seem to be able to eradicate the malignancy. Indeed, discontinuation trials (STIM; TWISER; DADI) for those patients who achieved a profound molecular response showed 50% relapsing within 12 months. We performed a comparative analysis on 15 CML patients and one B-ALL patient, between the standard quantitative reverse-transcriptase PCR (qRT-PCR) and our genomic DNA patient-specific quantitative PCR assay (gDNA qPCR). Here we demonstrate that gDNA qPCR is better than standard qRT-PCR in disease monitoring after an average follow-up period of 200 days. Specifically, we statistically demonstrated that DNA negativity is more reliable than RNA negativity in indicating when TKIs therapy can be safely stopped

Durvalumab plus gemcitabine and cisplatin in advanced biliary tract cancer: An early exploratory analysis of real-world data

Background: The TOPAZ-1 phase III trial reported a survival benefit with the anti-programmed death cell ligand 1 (anti-PD-L1) durvalumab in combination with gemcitabine and cisplatin in patients with advanced biliary tract cancer. The present study investigated the efficacy and safety of this new standard treatment in a real-world setting.Methods: The analysed population included patients with unresectable, locally advanced or metastatic adenocarcinoma of the biliary tract treated with durvalumab in combination with gemcitabine and cisplatin at 17 Italian centres. The primary endpoint of the study was progression-free survival (PFS), whereas secondary endpoints included overall survival (OS), overall response rate (ORR) and safety. Unadjusted and adjusted hazard ratios (HRs) by baseline characteristics were calculated using the Cox proportional hazards model.Results: From February 2022 to November 2022, 145 patients were enrolled. After a median follow-up of 8.5 months (95% CI: 7.9-13.6), the median PFS was 8.9 months (95% CI: 7.4-11.7). Median OS was 12.9 months (95% CI: 10.9-12.9). The investigator-assessed confirmed ORR was 34.5%, and the disease control rate was 87.6%. Any grade adverse events (AEs) occurred in 137 patients (94.5%). Grades 3-4 AEs occurred in 51 patients (35.2%). The rate of immune-mediated AEs (imAEs) was 22.7%. Grades 3-4 imAEs occurred in 2.1% of the patients. In univariate analysis, non-viral aetiology, ECOG PS >0 and NLR >= 3 correlated with shorter PFS.Conclusion: The results reported in this first real-world analysis mostly confirmed the results achieved in the TOPAZ-1 trial in terms of PFS, ORR and safety

Coulomb dissociation of O-16 into He-4 and C-12

We measured the Coulomb dissociation of O-16 into He-4 and C-12 within the FAIR Phase-0 program at GSI Helmholtzzentrum fur Schwerionenforschung Darmstadt, Germany. From this we will extract the photon dissociation cross section O-16(alpha,gamma)C-12, which is the time reversed reaction to C-12(alpha,gamma)O-16. With this indirect method, we aim to improve on the accuracy of the experimental data at lower energies than measured so far. The expected low cross section for the Coulomb dissociation reaction and close magnetic rigidity of beam and fragments demand a high precision measurement. Hence, new detector systems were built and radical changes to the (RB)-B-3 setup were necessary to cope with the high-intensity O-16 beam. All tracking detectors were designed to let the unreacted O-16 ions pass, while detecting the C-12 and He-4