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In this paper, we investigate the use of a positron emission tomography (PET) system to monitor the proton therapy. The monitoring procedure is based on the comparison between the ${ \beta }+$ activity generated in the irradiated volume during the treatment, with the ${ \beta }+$ activity distribution obtained with Monte Carlo (MC) simulation. The dedicated PET system is a dual head detection system; each head is composed of nine scintillating LYSO crystal matrices read out independently with a custom modularized acquisition system. Our experimental data were acquired at the Cyclotron Centre Bronowice, Institute Nuclear Physics in Krakow, Poland, and were simulated with the FLUKA MC code. Homogeneous and heterogeneous plastic phantoms were irradiated with monoenergetic 130 MeV protons. The capabilities of our PET system to distinguish different irradiated materials were investigated, and the proton pencil-beams were used as probes. Our focus was to analyze the activity width and the total activity event number in several cases. Irradiations were performed using either single pencil-beams one at a time, or two pencil-beams during the same data taking. The comparison of 1-D activity profile for experimental data and MC simulation were always in good agreement showing that, the treatment quality assessment in proton therapy can be based on ${ \beta }+$ activity measurements.

In this paper, an FPGA-based plain delay line time-to-digital converters (TDC) is presented, together with a theoretical model on its timing properties. The TDC features an automated calibration system implemented in the on-chip processor of an SoC-FPGA, uses a low amount of FPGA resources and is therefore suitable for applications requiring a high number of channels, such as time-of-flight positron emission tomography (PET). We first investigated the importance of calibration and validated the theoretical model on the TDC timing properties. Finally, the device has been embodied into a two channel PET acquisition system and tested. We found the calibration essential to obtain a good time resolution (38-ps FWHM in comparison with a 78-ps FWHM obtained with the uncalibrated device). The model we developed is able to predict the TDC timing properties. They are shown to be related to the fundamental parameters of the used FPGA technology. In particular, the best achievable time resolution of this specific architecture (plain tapped delay line on FPGA) is set to about 30 ps by the sum of the setup and hold times of the registers in the FPGA. The timing resolution of the two-channel setup is about 118 ps.

Hadrontherapy is a method for treating cancer with very targeted dose distributions and enhanced radiobiological effects. To fully exploit these advantages, in vivo range monitoring systems are required. These devices measure, preferably during the treatment, the secondary radiation generated by the beam-tissue interactions. However, since correlation of the secondary radiation distribution with the dose is not straightforward, Monte Carlo (MC) simulations are very important for treatment quality assessment. The INSIDE project constructed an in-beam PET scanner to detect signals generated by the positron-emitting isotopes resulting from projectile-target fragmentation. In addition, a FLUKA-based simulation tool was developed to predict the corresponding reference PET images using a detailed scanner model. The INSIDE in-beam PET was used to monitor two consecutive proton treatment sessions on a patient at the Italian Center for Oncological Hadrontherapy (CNAO). The reconstructed PET images were updated every 10 s providing a near real-time quality assessment. By half-way through the treatment, the statistics of the measured PET images were already significant enough to be compared with the simulations with average differences in the activity range less than 2.5 mm along the beam direction. Without taking into account any preferential direction, differences within 1 mm were found. In this paper, the INSIDE MC simulation tool is described and the results of the first in vivo agreement evaluation are reported. These results have justified a clinical trial, in which the MC simulation tool will be used on a daily basis to study the compliance tolerances between the measured and simulated PET images.

In this paper a FPGA-based delay line TDC architecture is presented, featuring an automated calibration system. We were able to predict and test experimentally the TDC timing properties. They were shown to be related to the fundamental parameters of the used FPGA technology. In particular, the best achievable time resolution of this specific architecture (plain tapped delay line on FPGA) is set by to about 24 ps by the sum of the setup and hold times of the registers in the FPGA.

Positron emission tomography is one of the most mature techniques for monitoring the particles range in hadron therapy, aiming to reduce treatment uncertainties and therefore the extent of safety margins in the treatment plan. In-beam PET monitoring has been already performed using inter-spill and post-irradiation data, i.e. while the particle beam is off or paused. The full beam acquisition procedure is commonly discarded because the particle spills abruptly increase the random coincidence rates and therefore the image noise. This is because random coincidences cannot be separated by annihilation photons originating from radioactive decays and cannot be corrected with standard random coincidence techniques due to the time correlation of the beam-induced background with the ion beam microstructure. The aim of this paper is to provide a new method to recover in-spill data to improve the images obtained with full-beam PET acquisitions. This is done by estimating the temporal microstructure of the beam and thus selecting input PET events that are less likely to be random ones. The PET detector we used was the one developed within the INSIDE project and tested at the CNAO synchrotron-based facility. The data were taken on a PMMA phantom irradiated with 72 MeV proton pencil beams. The obtained results confirm the possibility of improving the acquired PET data without any external signal coming from the synchrotron or ad hoc detectors.

Cerenkov luminescence imaging (CLI) is an optical imaging modality recently proposed to image β emitting radionuclides through the Cerenkov light they produce in tissue. CLI has been suggested in particular for β− emitting isotopes, which are difficult to study by other means, and as a cost-effective alternative to PET, yet with reduced penetration depth and spatial resolution. In this work we tested the predictive capabilities of a Monte Carlo model developed within the Geant4 platform for the description of a CLI experiment. Our final goal is to use Monte Carlo simulations to quantitatively correlate the number of detected Cerenkov photons with the radionuclide distribution. The code could be used also as a tool for experiment planning, for example in evaluating CLI applications. To test the reliability of the Monte Carlo predictions, CLI measurements were performed with a simple geometry that can be easily simulated (a radionuclide diluted in water) and the CLI signal measured with an electron multiplying charge coupled device (EMCCD) was compared with the Monte Carlo prediction. We observed that, below a certain detection limit and for particular acquisition settings, the measured signal depended on the acquisition settings. Apart from these exceptions, the simulated CLI signal was systematically 0.8 times the measured one. This small and constant offset suggests that the code could have good predictive capabilities in water.

Positron range is one of the main physical effects limiting the spatial resolution of positron emission tomography (PET) images. If positrons travel inside a magnetic field, for instance inside a nuclear magnetic resonance (MR) tomograph, the mean range will be smaller but still significant. In this investigation we examined a method to correct for the positron range effect in iterative image reconstruction by including tissue-specific kernels in the forward projection operation. The correction method was implemented within STIR library (Software for Tomographic Image Reconstruction). In order to obtain the positron annihilation distribution of various radioactive isotopes in water and lung tissue, simulations were performed with the Monte Carlo package GATE [Jan et al. 2004 [1]] simulating different magnetic field intensities (0 T, 3 T, 9.5 T and 11 T) along the axial scanner direction. The positron range kernels were obtained for 68Ga in water and lung tissue for 0 T and 3 T magnetic field voxellizing the annihilation coordinates into a three-dimensional matrix. The proposed method was evaluated using simulations of material-variant and material-invariant positron range corrections for the HYPERImage preclinical PET-MR scanner. The use of the correction resulted in sharper active region boundary definition, albeit with noise enhancement, and in the recovery of the true activity mean value of the hot regions. Moreover, in the case where a magnetic field is present, the correction accounts for the non-isotropy of the positron range effect, resulting in the recovery of resolution along the axial plane. © 2016 Associazione Italiana di Fisica Medica.

Positron emission tomography (PET) iterative 3D reconstruction is a very computational demanding task. One of the main issues of the iterative reconstruction concerns the management of the system response matrix (SRM). The SRM models the relationship between the projection and the voxel space and its memory footprint can easily exceed hundreds of GB. Moreover, in order to make the reconstruction fast enough not to hinder its practical application, the SRM must be stored in the random access memory of the workstation used for the reconstruction. This issue is normally solved by implementing efficient storage schemes and by reducing the number of redundant patterns in the SRM through symmetries. However, finding a sufficient number of symmetries is often non-trivial and is typically performed using dedicated solutions that cannot be exported to different detectors and geometries. In this paper, an automatic approach to reduce the memory footprint of a pre-computed SRM is described. The proposed approach was named symmetry search algorithm (SSA) and consists in an algorithm that searches for some of the redundant patterns present in the SRM, leading to its lossy compression. This approach was built to detect translations, reflections and coordinates swap in voxel space. Therefore, it is particularly well suited for those scanners where some of the rotational symmetries are broken, e.g. small animal scanner where the modules are arranged in a polygonal ring made of few elements, and dual head planar PET systems. In order to validate this approach, the SSA is applied to the SRM of a preclinical scanner (the IRIS PET/CT). The data acquired by the scanner were reconstructed with a dedicated maximum likelihood estimation maximization algorithm with both the uncompressed and the compressed SRMs. The results achieved show that the information lost due to the SSA compression is negligible. Compression factors up to 52 when using the SSA together with manually inserted symmetries and up to 204 when using the SSA alone, can be obtained for the IRIS SRM. These results come without significant differences in the values and in the main quality metrics of the reconstructed images, i.e. spatial resolution and noise. Although the compression factors depend on the system considered, the SSA is applicable to any SRM and therefore it can be considered a general tool to reduce the footprint of a pre-computed SRM.

Dosimetry in Hadrontherapy M. Marafini, A. Attili, G. Battistoni, N. Belcari, M.G. Bisogni, N. Camarlinghi, F. Cappucci, M. Cecchetti, P. Cerello, F. Ciciriello , G.A.P. Cirrone, S. Coli, F. Corsi , G. Cuttone, E. De Lucia, S. Ferretti, R. Faccini, E. Fiorina, P.M. Frallicciardi, G. Giraudo, E. Kostara, A. Kraan, F. Licciulli , B. Liu, N. Marino, C. Marzocca , G. Matarrese , C. Morone, M. Morrocchi, S. Muraro, V. Patera, F. Pennazio, C. Peroni, L. Piersanti, M.A. Piliero, G. Pirrone, A. Rivetti, F. Romano, V. Rosso, P. Sala, A. Sarti, A. Sciubba, G. Sportelli, C. Voena, R. Wheadon and A. Del Guerra Museo Storico della Fisica e Centro Studi e Ricerche E. Fermi , Roma, Italy b−f INFN Sezione di: Roma, Roma; Torino, Torino; Milano, Milano; Pisa, Pisa; Bari, Bari; Italy Laboratori Nazionali del Sud dell'INFN, Catania, Italy Laboratori Nazionali di Frascati dell'INFN, Frascati, Italy Dipartimento di Scienze di Base e Applicate per Ingegneria, Sapienza Universita di Roma, Roma, Italy

The production of very neutron-deficient isotopes near 100Sn has been investigated by using on-line mass separation of evaporation residues produced by heavy-ion induced complete-fusion reactions. We measured the cross sections for 99Cd, 100In, 101Sn and 102In via 58Ni+58Ni fusion reactions followed by cluster emission, and via 58Ni+50Cr fusion reactions accompanied by evaporation of protons, neutrons or α particles. Both types of reactions yield similar cross sections for the production of exotic nuclei near 100Sn. The data are discussed in comparison with results obtained from statistical-model calculations.

It is well known that a monochromatic X-ray source with an energy optimized for the organ thickness to be imaged could result in a better image quality in transmission radiology. In this paper we present the preliminary investigation for the implementation of this technique in computer tomography (CT) imaging. The detection system is based on a 1 mm thick silicon pixel detector bump bonded to a VLSI read-out, Medipix2. This detector ensures a good detection efficiency (46%) in the used energy range (60 kVp) with a good spatial resolution that arises from a 55 μm square pixel. The Medipix2 read-out electronics is not only a single photon counting system, but has also the capability of dual-energy threshold, that allows us to detect only photons that are in a chosen energy window. In this paper we present the results obtained in CT imaging of small samples, by selecting various energy windows within a standard X-ray tube spectrum so as to maximize the differentiation between significant attenuation coefficients. This study is preliminary for a future development of a dual-energy CT that could add functional information to the morphological information that is obtained in a CT examination.

Computed Tomography (CT) gives 3-D morpho logical images of the object under test. Anatomica information from CT can be used to compensate the limits of radionuclide imaging techniques. First of al it can help in physically localizing the uptake site within the body of the animal, thus allowing the ana tomical identification of the site. The CT scan also helps in performing more accurate radionuclide quan tification studies. These are usually performed by selecting a region-of-interest on the SPECT (or PET image: the higher spatial resolution of the CT allow more precise determination of the boundary of the ROI, and therefore of the number of counts within the ROI.

A micro-CT system prototype has been built at INFN in Pisa. This system will be later integrated with a micro-(S)PET scanner. Its main components are: a microfocus X-ray source with a peak voltage of up to 60 kV, a power of 10W and a focal spot size of 30 micrometers; a CCD coupled to columnar-grown CsI(Tl) scintillator for the detection of the X-rays, 6.144mm high by 147.456mm long, subdivided into 128 by 3076 square pixels, each with a size of 48 micrometers x 48 micrometers; stepping motors for the phantom roto-translation; a PCI acquisition board. Dedicated electronic boards were built for the control and the read-out of the CCD and a program in Labview was developed for the data acquisition. Reconstruction algorithms were implemented for fan-beam (2-D reconstruction) and cone-beam configuration (3-D reconstruction). The use of a CCD as X-ray detector together with an X-ray source, that operates in continuous mode only, has introduced a specific noise problem: this noise generates “ghosts” in the planar images, and therefore also in the tomographic images. This problem was overcome by developing a specific “double acquisition” technique. Planar images of a bar pattern (0.05 mm-thick lead layers, from 0.25 up to 10 line pairs per mm) were acquired to evaluate the X-ray detector performance: the CTF curve was extracted from the data, obtaining a value of 10% at 5 line pairs per millimeter and about 3% at 10 line pairs per millimeter. Tomographic acquisitions of a test phantom were performed: this phantom consists of a Plexiglas cylinder, 3 cm of diameter, with holes from 3 mm down to 0.6 mm of diameter, filled with different materials. The contrast resolution was extracted from the reconstructed images: a value of 6 % (in water) for a cubic voxel size of 80 micrometers was obtained. At present, we are working to improve the acquisition speed of the system and to optimise the acquisition parameters (such as the X-ray source spectrum).

The selective energy deposition of hadrontherapy has led to a growing interest in quality assurance techniques of dose delivery. In particular, the interest in Positron Emission Tomography (PET) as a tool for treatment verification in proton therapy has become widespread in the last years and several research groups worldwide are currently investigating its clinical implementation.

The selective energy deposition of hadrontherapy has led to a growing interest in quality assurance techniques such as 'in-beam' PET. Due to the current lack of commercial solutions, dedicated detectors need to be developed. In this paper, we compare the performances of two different 'in-beam' PET systems which were simultaneously operated during and after low energy carbon ion irradiation of PMMA phantoms at GSI Darmstadt. The results highlight advantages and drawbacks of a novel in-beam PET prototype against a long-term clinically operated tomograph for ion therapy monitoring.

In this study a miniature, high-resolution detector head for a small-animal PET imaging system that has intrinsic depth of interaction (DOI) information is proposed. The design is hased upon the classic Anger camera principle, i.e. one detector module layer consists of a continuous slab of scintillator, viewed by a new type of compact silicon photodetector. The photodetector is the recently developed Silicon Photomultiplier (SiPM) that as well as being very compact has many other attractive properties: high gain at low bias voltage, excellent single-photoelectron resolution and fast timing. A detector head of 4/spl times/4 cm/sup 2/ in area is proposed, constructed from three module layers of the continuous detector described above. Here, a simulation study is carried out, using the Monte Carlo simulation package GEANT4. The simulation results are used to determine the performance of a single detector head and to optimize the geometry of the detector, resulting in a spatial resolution of up to /spl sim/0.6 mm full-width at half maximum (FWHM).

Gamma rays from the N = Z-2 nucleus (50)Fe have been observed, establishing the rotational ground state band up to the state J(pi) = 11+ at 6.994 MeV excitation energy. The experimental Coulomb energy differences, obtained by comparison with the isobaric analog states in its mirror (50)Cr, confirm the qualitative interpretation of the backbending patterns in terms of successive alignments of proton and neutron pairs. A quantitative agreement with experiment has been achieved by exact shell model calculations, incorporating the differences in radii along the yrast bands, and properly renormalizing the Coulomb matrix elements in the pf model space.

The emission of two coincident energetic (E≥8 MeV) gamma rays has been observed in the 187 MeV 37Cl+ 120Sn reaction by using the cluster detectors of the EUROBALL III array. Those events are attributed to the decay of the double giant dipole resonance built on highly excited states.

The ridge structure with ΔEγ=±30 keV, observed in the past in coincidence with protons emitted in the reaction 187 MeV 37Cl +120Sn and attributed to an hyperdeformed nuclear shape in 152Dy, has been studied in a new experiment performed with the EUROBALL III array. The ridge is now observed in coincidence with transitions in the yrast superdeformed band of 152Dy but no discrete rotational bands have been identified.

A complete study of the nuclear structure by means of gamma spectroscopy requires, in addition to the high resolution gamma measurement and accurate DCO's or angular distributions, the information concerning the Electric or Magnetic character of the transition. This information for transitions in nuclei far from stability valley is now reachable in the new generation of Ge-arrays based in composite detectors. EUROBALL III is a good example with the high polarization sensitivity of the 90 degrees ring of Clovers. The Polarization correlations PCO's measured in coincidence with the Cluster detectors permits to investigate transitions in weakly populated nuclei. In this contribution we present results on medium mass N=Z nuclei measured with EUROBALL III coupled with light particle ancillary detectors. (Less)

The high-spin states of the N=Z nucleus 64Ge have been investigated using the EUROBALL array coupled to the ISIS Si-ball and to a highly efficient n-Wall. Spins and parities were assigned on the basis of a DCO and of a polarization analysis.

The production of isotopes near 100Sn has been investigated by using on-line mass separation of evaporation residues produced by heavy-ion induced complete fusion reactions. We measured β-delayed protons and γ-rays, deduced the mass-separated beam intensities for 99Cd, 100In, 101Sn and 102In, and determined the corresponding production cross-sections σ for 58Ni+58Ni reactions followed by emission of nuclear clusters, and for 58Ni+50Cr reactions accompanied by emission of protons, neutrons and α particles. The results indicate that the σ values for reactions followed by emission of clusters are comparable with those for reactions proceeding through light particle emission. Due to recoil-loss effects in on-line mass separation, the former mechanism is less suitable than the latter one for producing such neutron-deficient nuclei in this kind of experiments.

The high-spin structure of the N≃Z nuclei 62,64,65Ga have been investigated using the EUROBALL array coupled to the ISIS Si-ball. The collective bands of such nuclei are then compared showing an unexpected behavior.

The capability of the scintimammography to diagnose subcentimeters sized tumors was increased by the employment of a dedicated gamma camera. The introduction of small field of view camera, based on pixellated scintillation array and position sensitive photomultiplier, allowed to enhance the geometric spatial resolution and contrast of the images due to reduced collimator-tumor distance. The aim of this paper is to investigate the realistic possibility of T1a tumors detection (/spl sim/5 mm size) by comparing the signal-to-noise ratio (SNR) values obtained by different imagers. To this end, we have utilized a self-designed solid breast phantom with different sized hot spots (tumors). The phantom consists of seven disks with different thickness, molded from resin epoxy activated with Co/sup 57/ isotope. The overlapped disks represent a pendula breast with about 800 cc volume. Hot spots have not wall. One disk has holes to fit the hot spots representing the different sized lesions. The imagers utilized were: a standard Anger Camera and three different cameras based on scintillator array, CsI(Tl) or NaI(Tl), coupled to position sensitive photomultiplier with different technologies, to make detectors with field of view of 3 and 5 inch. The experimental results are supported by Monte Carlo simulation. It was highlighted how spatial resolution is a predominant element in tumor visibility and how background causes a reduction of the image contrast. All gamma cameras show close results at SNR values less than 10 and a full detectability of 8 mm tumor size. However, the results show the 5 mm tumor size is lower detection limit for all cameras.

A prototype for positron emission mammography is under development within a collaboration of the Italian Universities of Pisa, Ferrara, Bologna and Roma. The device is composed of two stationary detection heads, each with an active area of 6 cm /spl times/ 6 cm, made of 30/spl times/30 YAP:Ce finger crystals of 2 mm /spl times/ 2 mm /spl times/ 30 mm. The EGSnrc Monte Carlo code has been used to perform a complete simulation of this camera. We have used a fast three-dimensional iterative algorithm (30 s per iteration on a PC-Pentium III 800 MHz processor) for image reconstruction. The performed study indicates that tumors of 5 mm diameter, i.e., 0.065 cm/sup 3/ volume, with 37 kBq/cm/sup 3/ (1 /spl mu/Ci/cm/sup 3/) specific activity embedded in a breast active phantom, are detectable in 10 minutes for a 10:1 tumor/background ratio with an 8.7 Signal-to-Noise Ratio value. Experimental measurements with the small animal tomograph YAP-PET have validated the Monte Carlo predictions.

We are developing a PEM detector head based on two planar detector heads each measuring 6/spl times/6cm/sup 2/. Each head is composed of a 3/spl times/3 matrix of R8520-C12 phototubes from Hamamatsu and a YAP:Ce array of 2/spl times/2/spl times/30mm/sup 3/ pixels manufactured by Crytur. The R8520 is a compact 25.7/spl times/25.7mm/sup 2/ square detector that has an active area of 22/spl times/22mm/sup 2/. It has an excellent imaging performance and its square shape lends it well to PEM applications where a large active area is important to maximise sensitivity. However, even when tiled, the R8520-C12 only has an active area of 73%. Therefore, in an effort to recover the pixels lying on the detector boundaries that are not directly viewed by the active area, we have used a technique involving a quartz light diffuser between the crystal matrix and the PSPMT detectors. It is possible to recover virtually 100% of the area, but at the expense of a reduction in the system spatial resolution. Therefore, we have tested two versions of the detector head; one with the quartz diffuser which should provide a better sensitivity through maximised active area, and a second with no quartz that should have a superior imaging performance. Flood images are used to compare these two systems in terms of pixel identification and geometrical efficiency.

This work is developed within the framework of a larger project, which aims to develop a multimodal CT-SPET system dedicated to breast imaging. The goal of this paper is to optimize the choice of the various parameters involved in the design of a SPET system dedicated to breast imaging. In particular, we simulated different collimators, different tumor to background (T/B) ratios for two different spherical tumors with diameters of 5 mm and 8 mm. The performance of the explored cameras were analyzed in terms of SNR and image contrast (IC) values, calculated on the reconstructed images. In addition, we investigated the visibility limits of the system, by modifying the tumor size, the T/B value, and the diameter of the breast phantom (8 cm, 10 cm, and 13 cm). As a general tendency, we found out that a high-resolution camera is preferable, in terms of image contrast. On the other hand, the General Purpose collimator seems to give a smoother image, giving rise to SNR values comparable to those obtained with the High-Resolution collimator, even with a reduced contrast. High-sensitivity collimators seem to give a worse response on the reconstructed images. The 8 mm tumor is clearly visible for all the simulated conditions, even if it could be very close to the visibility limit for the High-Sensitivity collimator. The 5 mm tumor is close to the visibility limit for General Purpose and High-Resolution collimators, for a T/B ratio equal to 10:1 and is not visible with High-Sensitivity collimator. The smaller tumor is almost obscured by the background with the thickest breast (13 cm diameter).

Charged Particle Therapy (CPT) is a powerful radiotherapy technique for the treatment of deep-seated tumours characterized by a large dose released in the Bragg peak area (corresponding to the tumour region) and a small dose delivered to the surrounding healthy tissues. The precise measurement of the fragments produced in the nuclear interactions of charged particle beams with patient tissues is a crucial task to improve the clinical treatment plans. The FOOT (FragmentatiOn Of Target) experiment is an international project, funded by the Istituto Nazionale di Fisica Nucleare (INFN), aimed to study the dose released by the tissues and particle beams fragmentation. The target (16O, 12C) fragmentation induced by 150-400 MeV/n proton beams will be studied via the inverse kinematic approach, where 16O and 12C therapeutic beams collide on graphite and hydrocarbon target to provide the cross section on Hydrogen. A table-top detector is being developed and it includes a drift chamber as a beam monitor upstream of the target to measure the beam direction, a magnetic spectrometer based on silicon pixel and strip detectors, a scintillating crystal calorimeter able to stop the heavier produced fragments, and a ΔE detector, with TOF capability, for the particle identification. A setup based on the concept of the “Emulsion Cloud Chamber”, coupled with the interaction region of the electronic FOOT setup, will complement the physics program by measuring lighter charged fragments to extend the angular acceptance up to about 70 degrees. In this work, the experimental design and the requirements of the FOOT experiment will be discussed and preliminary results on the emulsion spectrometer tests will be presented.

Particle therapy uses proton or 12C beams for the treatment of deep-seated solid tumors. Due to the features of energy deposition of charged particles a small amount of dose is released to the healthy tissue in the beam entrance region, while the maximum of the dose is released to the tumor at the end of the beam range, in the Bragg peak region. However nuclear interactions between beam and patient tissues induce fragmentation both of projectile and target and must be carefully taken into account. In 12C treatments the main concern are long range fragments due to projectile fragmentation that release dose in the healthy tissue after the tumor, while in proton treatment the target fragmentation produces low energy, short range fragments along all the beam range. The FOOT experiment (FragmentatiOn Of Target) is designed to study these processes. Target nuclei (16O,12C) fragmentation induced by 150-250 AMeV proton beam will be studied via inverse kinematic approach. 16O,12C therapeutic beams, with the quoted kinetic energy, collide on graphite and hydrocarbons target to provide the cross section on Hydrogen. This configuration explores also the projectile fragmentation of these 16O,12C beams. The detector includes a magnetic spectrometer based on silicon pixel detectors and drift chamber, a scintillating crystal calorimeter with TOF capabilities, able to stop the heavier fragments produced, and a ΔE detector to achieve the needed energy resolution and particle identification. An alternative setup of the experiment will exploit the emulsion chamber capabilities. A specific emulsion chambers will be coupled with the interaction region of the FOOT setup to measure the production in target fragmentation of light charged fragments as protons, deuterons, tritons and Helium nuclei. The FOOT data taking is foreseen at the CNAO experimental room and will start during early 2018 with the emulsion setup, while the complete electronic detector will take data since 2019.

The higher physical selectivity of proton therapy demands higher accuracy in mon- itoring of the delivered dose, especially when the target volume is located next to critical or- gans and a fractionated therapy is applied. A method to verify a treatment plan and to ensure the high quality of the hadrontherapy is to use Positron Emission Tomography (PET), which takes advantage of the nuclear reactions between protons and nuclei in the tissue during irra- diation producing b þ -emitting isotopes. Unfortunately, the PET image is not directly propor- tional to the delivered radiation dose distribution; this is the reason why, at the present time, the verification of depth dose profiles with PET techniques is limited to a comparison between the measured activity and the one predicted for the planned treatment by a Monte Carlo model. In this paper we test the feasibility of a different scheme, which permits to re- construct the expected PET signal from the planned radiation dose distribution along beam di- rection in a simpler and more direct way. The considered filter model, based on the description of the PET image as a convolution of the dose distribution with a filter function, has already demonstrated its potential applicability to beam energies above 70 MeV. Our experimental investigation provides support to the possibility of extending the same approach to the lower energy range ((40, 70) MeV), in the perspective of its clinical application in eye proton therapy. a 2008 Published by Elsevier Ltd on behalf of Associazione Italiana di Fisica Medica.

Ion treatment can deliver an accurate and effective therapy. The verification of the delivered dose, after each irradiation, is an information that can improve the effectiveness of the complete treatment, if a comparison of the planned with the delivered dose is foreseen. A possible way to do this verification is measuring the beta+ emitters, like 11-C, 15-O, 10-C that are generated in irradiated tissues by nuclear reactions, by using a positron emission tomography (PET) system. We have realized a PET prototype based on two planar heads; each head is made up of a position sensitive photomultiplier coupled to a square matrix of same size of LYSO scintillating crystals (2x2x18 mm3 pixel dimensions for a total area of 5x5 cm2). A special resistive chain and a dedicated electronic board that performs signal amplification and digitization were realized. A 3D Maximum Likelihood Expectation Maximization reconstruction program that uses all of the collected lines-of-response was implemented. This prototype was tested at the INFN-LNS proton facility in Catania (Italy), where clinical treatment of ocular pathologies in patients is performed. In this paper we present: the results obtained for the range monitoring in monoenergetic and extended proton irradiations of homogeneous PMMA cylinders; the dependence on different density values and stoichiometry with inhomogeneous phantoms; the spatial relationship between the dose distribution and its PET image.

We have developed a SPEMT (Single Photon Emission MammoTomography) scanner that is made up of two cameras rotating around the pendulous breast of the prone patient, in Vertical Axis of Rotation (VAoR) geometry. Monte Carlo simulations indicate that the device should be able to detect tumours of 8 mm diameter with a tumour/background uptake ratio of 5:1. The scanner field of view is 41.6 mm height and 147 mm in diameter. Each head is composed of one pixilated NaI(Tl) crystal matrix coupled to three Hamamatsu H8500 64-anodes PMT’s read out via resistive networks. A dedicated software has been developed to combine data from different PMT’s, thus recovering the dead areas between adjacent tubes. A single head has been fully characterized in stationary configuration both in active and dead areas using a point-like source in order to verify the effectiveness of the readout method in recovering the dead regions. The scanner has been installed at the Nuclear Medicine Division of the University of Pisa for its validation using breast phantoms. The very first tomographic images of a breast phantom show a good agreement with Monte Carlo simulation results.

Proton therapy can overcome the limitations of conventional radiotherapy due to the more selective energy deposition in depth and to the increased biological effectiveness. Verification of the delivered dose is desirable, but the complete stopping of the protons in patient prevents the application of electronic portal imaging methods that are used in conventional radiotherapy During proton therapy β + emitters like 11 C, 15 O, 10 C are generated in irradiated tissues by nuclear reactions. The measurement of the spatial distribution of this activity, immediately after patient irradiation, can lead to information on the effective delivered dose. First, results of a feasibility study of an in-beam PET for proton therapy are reported. The prototype is based on two planar heads with an active area of about 5×5 cm 2 . Each head is made up of a position sensitive photomultiplier coupled to a square matrix of same size of LYSO scintillating crystals (2×2×18 mm 3 pixel dimensions). Four signals from each head are acquired through a dedicated electronic board that performs signal amplification and digitization. A 3D reconstruction of the activity distribution is calculated using an expectation maximization algorithm. To characterize the PET prototype, the detection efficiency and the spatial resolution were measured using a point-like radioactive source. The validation of the prototype was performed using 62 MeV protons at the CATANA beam line of INFN LNS and PMMA phantoms. Using the full energy proton beam and various range shifters, a good correlation between the position of the activity distal edge and the thickness of the beam range shifter was found along the axial direction.

We have developed a tomograph for single photon emission imaging (SPECT) of the breast for the detection of small size tumors. The SPECT is mounted on a ring that is rotating around the breast with the patient in prone position. The breast will be imaged by two opposing detector heads of approximately 5 × 15 cm 2 each, with a field of view about 13 cm wide. Each head is made up of one pixilated NaI crystal matrix coupled to three Hamamatsu H8500 PMTs. A “general purpose” lead collimator is positioned in front of the crystal. Detailed simulations have been made for the optimization and the evaluation of the detector performances. Monte Carlo results indicate that tumors of 8 mm diameter are detectable with a tumor/background uptake ratio of 5:1. The experimental characterization of the detector head is presented. The rotating ring is now being assembled.

The in-beam PET is a novel PET application to image the beta+ activity induced in biological tissues by hadronic therapeutic beams. Thanks to the correlation existing between beam-delivered dose profiles and beam-induced activity profiles, in vivo information about the effective ion paths can be extracted from the in-beam PET image. In-situ measurements, immediately after patient irradiation, are recommended in order to exploit the maximum statistics, by detecting the contribution provided by short lived isotopes. A compact, dedicated tomograph should then be developed for such an application, so as to be used in the treatment room. We have realized a small PET prototype in order to demonstrate the feasibility of such technique for the monitoring of proton therapy of ocular tumors at the CATANA facility (Catania, Italy). The DoPET (dosimetry with a positron emission Tomograph) tomograph consists of two planar heads, with an active area of about 5 cm x 5 cm. Each head is made up of a squared position sensitive photomultiplier (Hamamatsu H8500) coupled to a matrix of the same size of LYSO scintillating crystals (2 mm times 2 mm times 18 mm pixel dimensions). Dedicated, compact electronic boards are used for the signal multiplexing, amplification and digitization. The distance between the pair can be set from 10 cm up to a maximum of about 20 cm. The validation of the prototype was performed using 62 MeV protons at the CATANA beam line and plastic phantoms. Different dose distributions have been delivered and a good correlation between the distal fall-off of the activity profiles and of the dose profiles was found, i.e., better than 2 mm along the beam direction.

We have developed a compact Single Photon Emission MammoTomography (SPEMT) scanner capable of imaging the breast for the detection of small size (T1b) tumors. The scanner has a vertical-axis-of-rotation (VAOR) geometry, in which two gamma cameras orbit around a pendulous breast of a prone patient. The SPECT system is rotating around the vicinity of the breast in order to achieve high spatial resolution. The system field-of-view is 147 mm diameter and 41.6 mm height. Each head is made up of one pixilated NaI(Tl) crystal matrix with 2.2 mm pitch and 6 mm thickness coupled to three Hamamatsu H8500 64-anodes PMT’s. The measured performance confirm that the system could overcome the present clinical sensitivity limit (about 1 cm diameter) for the detection of small size tumors.