Cristiano Lino Fontana

Design of the rapidly relocatable tagged neutron inspection system of the C-BORD project

Within the framework of the European H2020 C-BORD project, aiming at improving container inspection technologies, a compact and “Rapidly Relocatable Tagged Neutron Inspection System”, called RRTNIS, is being developed taking into account past EURITRACK experience with a portal TNIS, and the latest technologies in terms of associated particle neutron generator and data acquisition electronics. A dedicated shield surrounding the neutron generator has been designed with MCNP6 to limit the size of the restricted area and the count rate on gamma detectors, which are located very close to the generator. This new design with “reflection” detectors only, i.e. in backscattering position, is indeed more efficient to detect suspect items, like explosives or illicit drugs, in bottom regions of the container, compared to EURITRACK detectors which were mainly located above the container. It also allows designing a relocatable system for different inspection sites like seaports, borders, or other checkpoints. Dose and count rate calculations are presented to determine the restricted area and facilitate the design of the data acquisition electronics, respectively.

Feasibility tests of a dual modality system for imaging using gamma rays and NIR light

We are developing a dual system for small-animal imaging in multimodality studies, which consists of a highspatial resolution gamma-camera and a scanner for Near-Infra-Red (NIR) light. The gamma-camera is assembled from a position-sensitive photomultiplier and a scintillation-crystal with parallel-hole collimator. On the other hand, the NIR imaging is designed for near-object scanning, and features two operational modes: Transmission and Fluorescence. In the Transmission mode, the NIR light, coming from five different wavelength LEDs, crosses the sample and is subsequently measured by an array sensor. In the Fluorescence mode, the emission from nanoparticles, such as singlewalled carbon nanotubes (SWCNTs) administered in the imaged object, is excited using the laser. The gamma-camera energy and spatial resolutions have been measured. This latter has been assessed by using specially-designed phantoms like capillary tubes or volumes with cavities filled with a radioactive solution. The NIR-scanner spatial r...

Feasibility study of the proton yield from the reaction D(3He,p)4 He as a possible tool for radiotherapy treatment

Recent achievements in proton and carbon ions therapy have shown the importance of the hadron therapy methods. Aiming at radiotherapy applications such as dermatological and intra-operative procedures, where a short range treatment is needed, we have studied the use of nuclear reactions induced by low energy ions from small accelerators. A very suitable reaction is D(3He,p)4He, using 3He+ ions with energies of about 800 keV. The resulting protons have energies above 17 MeV and could deliver significant radiation dose depending on the accelerator 3He+ beam current and the irradiation time. The deuterium containing target was prepared by reactive magnetron sputtering of titanium in Ar and Ar + D2 radiofrequency plasma on a substrate of Silicon. The Ti-Dx stoichiometry and deuterium content was determined by Ion Beam Analysis. The accelerated 3He+ beam was provided by the 2.5MV Van de Graaff accelerator at the National Laboratories of Legnaro, INFN, Italy. Proton yield as a function of the beam current at different forward scattering angles has been studied for the energies of the incoming 3He+ in the 700keV – 800keV energy interval. The irradiated volume and the radiation dose in biological tissues as a function of the proton energy and proton yield has been estimated. Possible applications in small animal treatment studies as well as potential clinical radiotherapy applications are discussed.

Performance Analysis of Multi-Wavelength Transmission Scanner for Polarized NIR Light

A system for small-object imaging, comprising a multiple-wavelength scanner for Near Infra-Red (NIR) light is under development in the Laboratory of Radiopharmaceuticals and Molecular Imaging (LRMI) at the National Laboratories of Legnaro, INFN, Italy. The System performs scanning of biological objects using NIR light in the interval of 900nm − 1700nm. The scanned region is a rectangular with dimensions of 50mm × 80mm and is performed by consecutive positioning of InGaAs linear image sensor sliding close to the scanned object. The scanning is carried out in two different modes. The first mode is performed in transmitted linearly polarized NIR light using a set of five light emitting diodes with fixed wavelengths. The process of scanning is realized by a consecutive positioning of the NIR sensor and signal acquisition at the corresponding position. In the second scanning mode the fluorescence emission of nanoparticles such as single-walled carbon nanotubes (SWCNTs), administered in the imaged object, is excited by NIR lasers with different wavelengths. Spatial resolution of the system for transmitted linearly polarized NIR at five fixed wavelengths has been determined. Polarimetric measurements of some optically active sugars such as fructose and lactose were conducted at some fixed wavelengths in the range of 900–1200nm. The system sensitivity with respect to the concentrations of these agents has been estimated.

Tomographic Back‐Projection Algorithm for “Incomplete” Compton X‐Rays Detectors

A “Compton” detector finds the direction of an X‐ray by letting it interact with a gaseous, liquid or thin solid material (Tracker) and employing no collimators. This paper takes into account the case of an “incomplete” solid Tracker where the recoiling electron travels only a few dozen microns and cannot be followed. However, impact positions and incoming and outgoing energies are measured. In this situation, exploiting the Compton Scattering formula, one is only able to identify a cone whose surface the X‐ray belongs to. On the other hand, Compton tomography luckily requires only a few views (for example rotating the apparatus in just four positions around the subject), as the “electronic collimation” that takes place in each position already extracts X‐rays coming from many directions. A back‐projection algorithm that combines the reconstructed “cones” in space, weighed according to the Klein‐Nishina formula, has been applied to the special case of small animal SPECT (Single Photon Emission Computed To...

X-rays Compton detectors for Biomedical application

Collimators are usually needed to image sources emitting X‐rays that cannot be focused. Alternately, one may employ a Compton Camera (CC) and measure the direction of the incident X‐ray by letting it interact with a thin solid, liquid or gaseous material (Tracker) and determine the scattering angle. With respect to collimated cameras, CCs allow higher gamma‐ray efficiency in spite of lighter geometry, and may feature comparable spatial resolution. CCs are better when the X‐ray energy is high and small setups are required. We review current applications of CCs to Gamma Ray Astronomy and Biomedical systems stressing advantages and drawbacks. As an example, we focus on a particular CC we are developing, which is designed to image small animals administered with marked pharmaceuticals, and assess the bio‐distribution and targeting capability of these latter. This camera has to address some requirements: relatively high activity of the imaged objects; detection of gamma‐rays of different energies that may rang...