In the present paper we report the development of the Continuous Motion scanning technique and its implementation for a new generation of scanning systems. The same hardware setup has demonstrated a ...significant boost in the scanning speed, reaching 190 cm
/h. The implementation of the Continuous Motion technique in the LASSO framework, as well as a number of new corrections introduced are described in details. The performance of the system, the results of an efficiency measurement and potential applications of the technique are discussed.
In recent decades, deep transformations have been reshaping academia and the research environment. Reforms in funding structures, research assessment, and accountability procedures are still ...redesigning the practices in academic work, redefining research schedules, and determining relevant effects on scientific career paths. Despite European policies efforts towards the development of more responsible and inclusive research, the processes emerging from these transformations of academic contexts are producing new inequalities and strengthening old ones. New rules in the recruitment and career progression of researchers reduce, in some instances, and intensify, in others the pre-existing gender gaps, with varying impact on researchers, according to their belonging to different cohorts, gender or minority groups, and on universities, according to size and regional contexts. Adopting an intersectional perspective, contributions in this volume focus on gendering processes in Italian academia. Altogether, they succeed in accomplishing a double result: to unveil the gendered character of academic and research practices and to trace emergent paths towards their reshaping into more equitable and inclusive ones.
Objective: To evaluate the role of computer aided detection (CAD) in improving the interpretation of screening mammograms
Material and methods: Ten radiologists underwent a proficiency test of ...screening mammography first by conventional reading and then with the help of CAD. Radiologists were blinded to test results for the whole study duration. Results of conventional and CAD reading were compared in terms of sensitivity and recall rate. Double reading was simulated combining conventional readings of four expert radiologists and compared with CAD reading.
Results: Considering all ten readings, cancer was identified in 146 or 153 of 170 cases (85.8 vs. 90.0%;
χ
2=0.99, df=1,
P=0.31) and recalls were 106 or 152 of 1330 cases (7.9 vs. 11.4%;
χ
2=8.69, df=1,
P=0.003) at conventional or CAD reading, respectively. CAD reading was essentially the same (sensitivity 97.0 vs. 96.0%;
χ
2=7.1, df=1,
P=0.93; recall rate 10.7 vs. 10.6%;
χ
2=1.5, df=1,
P=0.96) as compared with simulated conventional double reading.
Conclusion: CAD reading seems to improve the sensitivity of conventional reading while reducing specificity, both effects being of limited size. CAD reading had almost the same performance of simulated conventional double reading, suggesting a possible use of CAD which needs to be confirmed by further studies inclusive of cost-effective analysis.
Abstract We describe the implementation in several Italian hospitals of a computer aided detection (CAD) system, named GPCALMA (grid platform for a computer aided library in mammography), for the ...automatic search of lesions in X-ray mammographies. GPCALMA has been under development since 1999 by a community of physicists of the Italian National Institute for Nuclear Physics (INFN) in collaboration with radiologists. This CAD system was tested as a support to radiologists in reading mammographies. The main system components are: (i) the algorithms implemented for the analysis of digitized mammograms to recognize suspicious lesions, (ii) the database of digitized mammographic images, and (iii) the PC-based digitization and analysis workstation and its user interface. The distributed nature of data and resources and the prevalence of geographically remote users suggested the development of the system as a grid application: the design of this networked version is also reported. The paper describes the system architecture, the database of digitized mammographies, the clinical workstation and the medical applications carried out to characterize the system. A commercial CAD was evaluated in a comparison with GPCALMA by analysing the medical reports obtained with and without the two different CADs on the same dataset of images: with both CAD a statistically significant increase in sensitivity was obtained. The sensitivity in the detection of lesions obtained for microcalcification and masses was 96% and 80%, respectively. An analysis in terms of receiver operating characteristic (ROC) curve was performed for massive lesion searches, achieving an area under the ROC curve of Az = 0.783 ± 0.008. Results show that the GPCALMA CAD is ready to be used in the radiological practice, both for screening mammography and clinical studies. GPCALMA is a starting point for the development of other medical imaging applications such as the CAD for the search of pulmonary nodules, currently under development in the framework of an INFN-funded project.
This paper describes the development and characterization of a ΔE-TOF detector composed of a plastic scintillator bar coupled at both ends to silicon photomultipliers. This detector is a prototype of ...a larger version which will be used in the FOOT (FragmentatiOn Of Target) experiment to identify the fragments produced by ion beams accelerated onto a hydrogen-enriched target. The final ΔE-TOF detector will be composed of two layers of plastic scintillator bars with orthogonal orientation and will measure, for each crossing fragment, the energy deposited in the plastic scintillator (ΔE), the time of flight (TOF), and the coordinates of the interaction position in the scintillator. To meet the FOOT experimental requirements, the detector should have energy resolution of a few percents and time resolution of 70 ps, and it should allow to discriminate multiple fragments belonging to the same event. To evaluate the achievable performances, the detector prototype was irradiated with protons of kinetic energy in the 70–230 MeV range and interacting at several positions along the bar. The measured energy resolution σΔE∕ΔE was 6–14%, after subtracting the fluctuations of the deposited energy. A time resolution σ between 120 and 180 ps was obtained with respect to a trigger detector. A spatial resolution σ of 1.9 cm was obtained for protons interacting at the center of the bar.
We present the design and preliminary imaging evaluation of a bench-top apparatus for X-ray cone-beam breast computed tomography (CBBCT), assembled for technical evaluation and for laboratory tests ...of various optimization techniques for CBBCT. The prototype is characterized by the computer control of the X-ray tube (W anode, 35-80 kVp, 0.25 mA, 50 ¿m focal spot size), CsI:Tl CMOS flat panel detector (12×12 cm 2 area, 50 ¿m pitch, up to 9 fps at 4 × 4 binning), motorized translation and rotation stages with eight degrees of freedom, and fan-beam or cone-beam backprojection software. First cone-beam tomographic images of two 14-cm diameter hemiellipsoidal PMMA breast phantoms are presented.
The use of carbon ion beams in radiotherapy presents significant advantages when compared to traditional x-ray. In fact, carbon ions deposit their energy inside the human body at the end of their ...range, the Bragg peak. Unlike x-ray beams, where the energy deposition decreases exponentially inside the irradiated volume, the shape of carbon beams is sharp and focused. Advantages are an increased energy released in the cancer volume while minimizing the irradiation to healthy tissues. Currently, the use of carbon beams is limited by the poor knowledge we have about the effects of the secondary fragments on the irradiated tissues. The secondary particles produced and their angular distribution is crucial to determine the global dose deposition. The knowledge of the flux of secondary particles plays a key role in the real time monitoring of the dose profile in hadron therapy. We present a detector based on nuclear emulsions for fragmentation measurements that performs a sub-micrometric tridimensional spatial resolution, excellent multi-particle separation and large angle track recognition. Nuclear emulsions are assembled in order to realize a hybrid detector (emulsion cloud chamber (ECC)) made of 300 μm nuclear emulsion films alternated with lead as passive material. Data reported here have been obtained by exposing two ECC detectors to the fragments produced by a 400 MeV n−1 12C beam on a composite target at the GSI laboratory in Germany. The ECC was exposed inside a more complex detector, named FIRST, in order to collect fragments with a continuous angular distribution in the range 47°-81° with respect to the beam axis. Results on the angular distribution of fragments as well as their momentum estimations are reported here.
The use of carbon ion beams in radiotherapy presents significant advantages when compared to traditional x-ray. Unlike x-ray beams, where the energy deposition decreases exponentially inside the ...irradiated volume, the shape of carbon beams is sharp and focused. Advantages are an increased energy released in the cancer volume while minimizing the irradiation to healthy tissues. Currently, the use of carbon beams is limited by the poor knowledge we have about the effects of the secondary fragments on the irradiated tissues. We present a detector based on nuclear emulsions for fragmentation measurements that performs a sub-micrometric tridimensional spatial resolution, excellent multi-particle separation and large angle track recognition. Nuclear emulsions are assembled in order to realize a hybrid detector (emulsion cloud chamber (ECC)) made of 300mum nuclear emulsion films alternated with lead as passive material. Results on the angular distribution of fragments as well as their momentum estimations are reported here.
We measured the spatial distribution of absorbed dose in a 14 cm diameter PMMA half-ellipsoid phantom simulating the uncompressed breast, using an X-ray cone-beam breast computed tomography ...apparatus, assembled for laboratory tests. Thermoluminescent dosimeters (TLD-100) were placed inside the phantom in six positions, both axially and at the phantom periphery. To study the dose distribution inside the PMMA phantom two experimental setups were adopted with effective energies in the range 28.7-44.4 keV. Different values of effective energies were obtained by combining different configurations of added Cu filtration (0.05 mm or 0.2 mm) and tube voltages (from 50 kVp to 80 kVp). Dose values obtained by TLDs in different positions inside the PMMA are reported. To evaluate the dose distribution in the breast shaped volume, the values measured were normalized to the one obtained in the inner position inside the phantom. Measurements with a low energy setup show a gradual increment of dose going from the "chest wall" to the "nipple" (63% more at the "nipple" compared to the central position). Likewise, a gradual increment is observed going from the breast axis toward the periphery (82% more at the "skin" compared to the central position). A more uniform distribution of dose inside the PMMA was obtained with a high energy setup (the maximum variation was 33% at 35.5 keV effective energy in the radial direction). The most uniform distribution is obtained at 44.4 keV. The results of this study show how the dose is distributed: it varies as a function of effective energy of the incident X-ray beam and as a function of the position inside the volume (axial or peripheral position).
The first in vivo tomographic 125 I imaging of the mouse thyroid carried out with the new MediSPECT small animal SPECT scanner is presented. The scanner is based on a fine pitch CdTe semiconductor ...pixel detector (14 × 14 mm 2 , 256 × 256 square pixel with a 55 m side) and equipped with a set of high resolution collimators. The collimation and detection units of the scanner are mounted on a gantry, rotating around a horizontal axis, along which is placed the small animal housing. In an in vivo test, the mouse was injected with a Na 125 I solution having a total activity of 31.8 MBq. The planar projections for SPECT reconstruction were acquired with a 300 m pinhole (magnification 1.47 and field of view of 9.6 × 9.6 mm 2 ). The projections were captured in a step-and-shoot fashion and were processed with an Ordered Subsets-Expectation Maximization reconstruction algorithm in order to obtain the SPECT images. Several 125 I imaging tests have been made by using phantoms to assess the detector spatial resolution. The measured spatial resolution with a 300 m pinhole is about 0.5 mm in planar imaging and better than 1 mm in tomographic imaging.
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