This work reports on the Limited Angle Tomography (LAT) studies of a novel Molecular Breast Imaging (MBI) system with radionuclides, made by two asymmetric SPECT-like detector heads with two different optics. MBI has a central role to play in detecting the small breast tumours, especially for dense breasts, due to its specificity in detecting tumours even in dense breasts. For this purpose, an innovative device has been developed at ISS in Rome, composed of a dual detector setup which combines images from two complementary detectors at the opposite sides of the compressed breast, and that allows spot compression and LAT for a tumour 3-D reconstruction. Our study tries to demonstrate the feasibility of using this novel system in LAT , where a small detector head with pinhole collimator is able to rotate around the breast phantom, to diagnose the small tumours and to improve the sensitivity and efficiency. Detector heads and phantom, LAT setup and first preliminary results, are presented.

The TOP-IMPLART project consists of the design and implementation of a linear proton accelerator, its control and monitoring systems for the treatment of superficial and semi-deep tumors. The energy of 150 MeV (corresponding to a penetration in tissue of about 15 cm) is a milestone in design being useful for the proton therapy treatment of almost 50% of tumors based on their position and depth (including ocular melanoma, head-neck tumors, pediatric tumors, and more superficial tumors). The capability to vary the intensity on a pulse-to-pulse basis combined with an electronic feedback system allows to get the required dose uniformity (2.5%) reducing the number of re-paintings. In this paper the state of the art and the objectives of the TOP-IMPLART project are described within the framework of the progress of Protontherapy.

Abstract The Intensity Modulated Proton Linear Accelerator for Cancer Therapy (TOP-IMPLART) is under development and construction by ENEA in collaboration with the Italian Institute of Health (ISS) and the Oncological Hospital Regina Elena-IFO with financial support of Regione Lazio. Its peculiar time structure (few microseconds pulse width) and very high peak intensity (≍ 109 proton/pulse) demand for ad hoc dose delivery monitors (DDM). The TOP-IMPLART DDM is based on ionization gas chambers. One segmented chamber prototype uses Micro Pattern Gaseous Detector technology for the 2-dimensional simultaneous x/y readout; the charge collected from each active segment (strips with pad-like shape) is readout by a dedicated gain-adaptable electronics. Two small, highly sensitive, integral ionization chambers, using the same electronics, complement the 2D chamber for the monitor of the single pulse beam charge, down to 1 pC/pulse. While under development and deployment of its accelerating modular cavities, the linear TOP-IMPLART beam is improved thanks also to the continuous monitoring and characterization by these devices, whose responses are periodically compared to calibrated dosimetric detectors such as real-time active microDiamond sensor, passive Alanine pellets, intrinsically stable integral Faraday Cup. Different calibration campaigns have been recently conducted to measure the recombination and dose-rate effects on the above ionization chambers. The outcome of these measurements shows clear electron-ion recombination in the chamber active volume, largely related to the high beam intensity and its small transverse cross section. Those effects can be taken into account and used to correct the actual measurement of the DDM. In this paper, the TOP-IMPLART project and the DDM devices are shortly presented and details of the above experimental studies are discussed.

The purpose of the present work is the study of reconstruction properties of a new Molecular Breast Imaging (MBI) device for the early diagnosis of breast cancer, in Limited Angle Tomography (LAT), by using two asymmetric detector heads with different collimators. The detectors face each other in anti-parallel viewing direction and, mild-compressing the breast phantom, they are able to reconstruct the inner tumour of the phantoms with only a limited number of projections using a dedicated maximum-likelihood expectation maximization algorithm. The phantoms, the MBI system, as well as the Monte Carlo simulator, are briefly described. The MBI system's model has been implemented in IDL, in order to evaluate the best LAT configuration of the system and its reconstruction ability by varying tumour's size, depth and uptake. The LAT setup in real and simulated configurations, as well as the maximum-likelihood method and the preliminary reconstruction results, are discussed.

In the framework of the Italian TOP-IMPLART project (Regione Lazio), ENEA-Frascati, ISS and IFO are developing and constructing the first proton linear accelerator based on an actively scanned beam for tumor radiotherapy with final energy of 150 MeV. An important feature of this accelerator is modularity: an exploitable beam can be delivered at any stage of its construction, which allows for immediate characterization and virtually continuous improvement of its performance. Currently, a sequence of 3 GHz accelerating modules combined with a commercial injector operating at 425 MHz delivers protons up to 35 MeV. Several dosimetry systems were used to obtain preliminary characteristics of the 35-MeV beam in terms of stability and homogeneity. Short-term stability and homogeneity better than 3% and 2.6%, respectively, were demonstrated; for stability an improvement with respect to the respective value obtained for the previous 27 MeV beam.

This paper draws attention to the study of performance of a new Molecular Breast Imaging (MBI) device, whose purpose is the early diagnosis of breast cancer, using Monte Carlo simulations. MBI provides functional and specific information that are more appropriated to dense breasts. Two asymmetric heads with different types of collimators, facing each other in anti-parallel viewing direction, characterize the system. Detectors and phantoms, together with the data taking procedure, are shortly reported. Monte Carlo simulations using the GATE (GEANT4 Application for Tomographic Emission) simulation toolkit have been implemented to evaluate the optimal detector configuration, in terms of sensitivity and spatial resolution, and also to reproduce the real experimental data. The device can be used both in spot compression and in Limited Angle Tomography (LAT); in the latter configuration one detector head with pinhole collimator is able to rotate around the breast in order to diagnose and localized the small tumors.

ABSTRACT A new Large-Acceptance Forward Angle Spectrometer [Super Bigbite Spectrometer (SBS)], is under development for the upcoming experiments in Hall A at the Thomas Jefferson National Accelerator Facility (Virginia, USA), where a longitudinally polarized (up to ) electron beam up to 12 GeV energy is now available. The excellent beam intensity (up to 100 A), combined with innovative polarized targets, will provide luminosity up to , opening interesting opportunities to investigate unexplored aspects of the inner structure of the nucleons. In one of the most demanding configuration, the new spectrometer will consist of a dipole magnet, one front charged particle tracker, two identical proton polarimeters with related back trackers and a segmented hadron calorimeter. The front tracker, placed just after the dipole magnet, consists of up to six layers of large area GEM (Gas Electron Multiplier) chambers (); each chamber is made by three adjacent GEM modules of active rectangular area (18 modules as a total). We have chosen the GEM technology in order to optimize spatial resolution (∼80 mm), high hit rate (), cost/performance and high radiation hardness. We present the main features of the SBS front tracker and its GEM detectors and, finally, we discuss the ongoing tracker commissioning at JLab and show some representative test results.

This Article is brought to you for free and open access by the Physics at ODU Digital Commons. It has been accepted for inclusion in Physics Faculty Publications by an authorized administrator of ODU Digital Commons. For more information, please contact digitalcommons@odu.edu. Repository Citation Urciuoli, G. M.; Hayes, D.; Hyde, C. E.; Ibrahim, H. F.; Ulmer, P.E.; and Jefferson Lab Hall A Collaboration, "Spectroscopy of Li-9 (Lambda) by Electroproduction" (2015). Physics Faculty Publications. 152. https://digitalcommons.odu.edu/physics_fac_pubs/152

A dedicated dose delivery monitor is under development for the TOP-IMPLART proton accelerator, the first LINAC for cancer therapy. It is expected to measure the beam intensity profile to precisely monitor the fully active 3+1D (x/y/z and intensity) dose delivery of each short pulse (few μs, 0.1-10 μA pulse current at ∼ 100 Hz) of the therapeutic proton beam (up to 230 MeV). The monitor system consists of planar gas chambers operating in ionization regime with cathode plane made of micro pattern pads alternately connected by orthogonal strips. The dedicated readout electronics features trans-impedance amplifier that dynamically adapts its integrating feedback capacitance to the incoming amount of charge, then opportunistically changing its gain. The measured absolute sensitivity is about 100 fC (better than 0.03 relative sensitivity), the dynamic range up to 10000 (2 gain settings) with time response at the level of few ns, and virtually no dead time. Small scale chamber prototype (0.875 mm pitch pads) and readout electronics have been tested and characterized under both electron (5 MeV) and proton (up to 27 MeV) beams.

Prostate cancer is the most common disease in men and the second leading cause of death from cancer. Generic large imaging instruments used in cancer diagnosis have sensitivity, spatial resolution, and contrast which are inadequate for the task of imaging details of a small organ such as the prostate. In addition, multimodality imaging can play a significant role in merging anatomical and functional details coming from simultaneous PET and MRI. Indeed, multiparametric PET/MRI was demonstrated to improve diagnosis, but it suffers from too many false positives. In order to address the above limits of the current techniques, we have proposed, built and tested, thanks to the TOPEM project funded by Italian National Institute of Nuclear Phisics, a prototype of an endorectal PET-TOF/MRI probe. In the applied magnification PET geometry, performance is dominated by a high-resolution detector placed closer to the source. The expected spatial resolution in the selected geometry is about 1.5mm FWHM and efficiency of a factor 2 with respect to what was obtained with the conventional PET scanner. In our experimental studies, we have obtained a timing resolution of ∼ 320 ps FWHM and at the same time a Depth of Interaction (DOI) resolution of under 1mm. Tests also showed that mutual adverse PET-MR effects are minimal. In addition, the matching endorectal RF coil was designed, built and tested. In the next planned studies, we expect that benefiting from the further progress in scintillator crystal surface treatment, in SiPM technology and associated electronics would allow us to significantly improve TOF resolution.

In the absence of accurate data on the free two-body hyperon-nucleon interaction, the spectra of hypernuclei can provide information on the details of the effective hyperon-nucleon interaction. Electroproduction of the hypernucleus Lambda-9Li has been studied for the first time with sub-MeV energy resolution in Hall A at Jefferson Lab on a 9Be target. In order to increase the counting rate and to provide unambiguous kaon identification, two superconducting septum magnets and a Ring Imaging CHerenkov detector (RICH) were added to the Hall A standard equipment. The cross section to low-lying states of Lambda-9Li is concentrated within 3 MeV of the ground state and can be fitted with four peaks. The positions of the doublets agree with theory while a disagreement could exist with respect to the relative strengths of the peaks in the doublets. A Lambda separation energy of 8.36 +- 0.08 (stat.) +- 0.08 (syst.) MeV was measured, in agreement with an earlier experiment.

We developed and tested a new charged particle tracking system, able to operate in high luminosity experiments, which will be installed at Jefferson Laboratory HallA (VA, USA) for optimally exploit the new 12GeV energy electron beam available at the end of 2013. The tracker is made of six GEM (Gas Electron Multiplier) large chambers and two 10×20cm2 planes of SIlicon microstrip Detectors (SIDs). Each GEM chamber is composed by three 40×50cm2 GEM modules, with two-dimensional strip readout, with expected spatial resolution of about 70μm. The same dedicated acquisition system will be used for both detectors (GEM & SID) for a grand total of more than 50,000 channels. The readout electronics is divided into two parts: the front-end cards (based on the existing APV25 chip), hosted on the detectors periphery and the digitizer, a multi purpose VME-64x/VXS board located far from the high radiation environment. The very same electronics has been adopted by the Olympus experiment (DESY, Hamburg, D) to read out the six GEM chambers of its luminosity monitor. The developed detectors and electronics are now ready for the production, which will last for the next 2 years.

The characteristics of the Jefferson Lab electron beam, together with those of the experimental equipment, offer a unique opportunity to study hypernuclear spectroscopy via electromagnetic induced (e,e′K+) reactions. Experiment 94-107 started a systematic study on 1p-shell targets, C12, Be9 and O16. For C12 for the first time measurable strength in the core-excited part of the spectrum between the ground state and the p state was shown in the BΛ12 spectrum. For O16 a high-quality NΛ16 spectrum was produced for the first time with sub-MeV energy resolution. A very precise Λ binding energy value for NΛ16, calibrated against the elementary (e,e′K+) reaction on hydrogen, has also been obtained. Preliminary data on the LiΛ9 spectrum shows some disagreement in strength for the second and third doublet with respect to the theory.

Prostate cancer is the most common disease in men and the second leading cause of cancer death. Generic large instruments for diagnosis have sensitivity, spatial resolution, and contrast inferior with respect to dedicated prostate imagers. Multimodality imaging can play a significant role merging anatomical and functional details coming from simultaneous PET and MRI. The TOPEM project has the goal of designing, building, and testing an endorectal PET-TOF MRI probe. The performance is dominated by the detector close to the source. Results from simulation show spatial resolution of ∼1.5mm for source distances up to 80mm. The efficiency is significantly improved with respect to the external PET. Mini-detectors have been built and tested. We obtained, for the first time, to our best knowledge, timing resolution of <400ps and at the same time Depth Of Interaction (DOI) resolution of 1mm or less.

A unique compact LINAC accelerator for proton therapy is under development in Italy within the TOP-IMPLART project. The proton beam will reach the kinetic energy of 230 MeV, it will have a widely variable current intensity (0.1–10 μA, with average up to 3.5 nA) associated with a high pulse repetition frequency (1–3.5 μs long pulses at 10–100 Hz). The TOP-IMPLART system will provide a fully active 3+1D dose delivery, that is longitudinal (energy modulation), transverse active spot scanning, and current intensity modulation. These accelerator features will permit a highly conformational dose distribution, which therefore requires an effective, online, beam monitor system with wide dynamic range, good sensitivity, adequate spatial resolution and rapid response. In order to fulfill these requisites a new device is under development for the monitoring of the beam intensity profile, its centroid and direction; it is based on transmission, segmented, ionization chambers with typical active area of 100 × 100 mm2. Micro pattern x/y pad like design has been used for the readout plane in order to maximize the field uniformity, reduce the chamber thickness and obtain both beam coordinates on a single chamber. The chamber prototype operates in ionization region to minimize saturation and discharge effects. Simulations (based on FLUKA) have been carried on to study the perturbation of the chamber on the beam parameters and the effects on the delivered dose (on a water phantom). The charge collected in each channel is integrated by dedicated auto-ranging readout electronics: an original scheme has been developed in order to have an input dynamic range greater than 104 with sensitivity better than 3%. This is achieved by a dynamical adjustment of the integrating capacitance to the signal intensity.

A new large-area, lightweight tracker based on the GEM technology is under development for the upcoming experiments in Hall A at Jefferson Lab, where a longitudinally polarized electron beam of 11 GeV will be available in late 2013. This beam, combined with innovative polarized targets, will provide luminosity up to 1039/(s⋅cm2) opening exciting opportunities to investigate unexplored aspects of the inner structure of the nucleon and the dynamics of its constituents. The GEM tracker design is presented in this paper.

Prostate cancer (PC) is the most common disease in western countries and a leading cause of cancer death. Powerful techniques and instruments for diagnosis such as CT, MRI, PET/SPECT suffer from limited spatial resolution, sensitivity and/or specificity. Dedicated detectors and techniques are needed. For this reason a new INFN research project (TOPEM) started with the goal of designing, building and testing an endorectal PET-TOF probe compatible with MRI, to be used in coincidence with an external dedicated detector and/or a standard PET ring. Multimodality imaging can play a significant role, merging anatomical and functional details coming from simultaneous PET and MRI (and MRS) scans. Good spatial resolution and Depth Of Interaction (DOI) resolution are needed in order to guarantee high performance in image reconstruction. Here the main focus is a characterization of the elementary detector unit, in terms of energy, timing and DOI resolution. Exploiting the TOF capability allows an increase in the SNR/NECR and also permits elimination of bladder background. Silicon Photo Multipliers (SiPM) are the obvious choice as photodetectors to be coupled with small finger scintillators. Good preliminary results have been obtained both on DOI and Timing resolutions.