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The correct quantification of the dose released in charged particle therapy treatments requires the knowledge of the double differential fragmentation cross section of particles composing both the beam and the target. The FragmentatiOn Of Target (FOOT) experiment aims at measuring these cross sections for ions of interest for charged particle therapy applications. This article describes the performance of the time-of-flight (TOF)-wall detector of the experiment. The detector is composed of two layers of 44 cm $\times 2$ cm $\times 3$ mm plastic scintillator bars (20 for each layer), arranged orthogonally and read-out by silicon photomultipliers. The detector is designed to identify the charge of fragments ranging from protons to oxygen ions, with a maximum energy of 700 MeV/u, by measuring the energy released in the scintillators and the TOF with respect to a start counter. In this study, the detector was scanned with carbon ions of energy between 115 and 400 MeV/u and with a 60-MeV proton beam. The measurements show an energy resolution ($\sigma _{E}/\mu _{E}$) between 6% and 4% and a contribution of the detector to the TOF system time resolution between 25 and 20 ps (standard deviation) for carbon ions and between 100 and 80 ps for protons. [ABSTRACT FROM AUTHOR]

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 aim of this work is to present an unfolding procedure which, starting from the \beta^+ activity distribution of ^11C measured with PET, leads to an estimation of the delivered dose, thus allowing a direct comparison with the planned one. The foundation of the proposed method is a filtering approach which describes the induced activity as a convolution of the dose distribution with a well defined filter function. As a solution we propose a method based on the Tikhonov theory which imposes a regularization constraint to the solution. Preliminary tests have been performed with Monte Carlo (MC) simulated data on homogeneous and inhomogeneous phantoms, showing robustness and spatial accordance between the numerically reconstructed dose and the simulated one. [ABSTRACT FROM AUTHOR]

We have developed a flexible, cost-efficient PET architecture adaptable to different applications and system geometries, such as positron emission mammography (PEM) and in-beam PET for dose delivery monitoring (ibPET). The acquisition system has been used to implement modularized dual planar detectors with very low front-end dead time, as required in PEM or in ibPET. The flexibility is obtained thanks to the FPGA-based, reprogrammable, TDC-less coincidence processor. The final goal is to propose an effective acquisition methodology and the construction of a compact, low-cost instrument able to provide early diagnosis and to improve the effectiveness of follow-up studies for smaller tumours with respect to those studied with present clinical equipment (e.g., whole-body PET, SPECT, or scintigraphy). [ABSTRACT FROM AUTHOR]

A time efficient optical model is proposed for GATE simulation of a LYSO scintillation matrix coupled to a photomultiplier. The purpose is to avoid the excessively long computation time when activating the optical processes in GATE. The usefulness of the model is demonstrated by comparing the simulated and experimental energy spectra obtained with the dual planar head equipment for dosimetry with a positron emission tomograph (DoPET). The procedure to apply the model is divided in two steps. Firstly, a simplified simulation of a single crystal element of DoPET is used to fit an analytic function that models the optical attenuation inside the crystal. In a second step, the model is employed to calculate the influence of this attenuation in the energy registered by the tomograph. The use of the proposed optical model is around three orders of magnitude faster than a GATE simulation with optical processes enabled. A good agreement was found between the experimental and simulated data using the optical model. The results indicate that optical interactions inside the crystal elements play an important role on the energy resolution and induce a considerable degradation of the spectra information acquired by DoPET. Finally, the same approach employed by the proposed optical model could be useful to simulate a scintillation matrix coupled to a photomultiplier using single or dual readout scheme. [ABSTRACT FROM PUBLISHER]

At the University of Pisa, the DoPET (Dosimetry with a Positron Emission Tomograph) project has focused on the development and characterization of an ad hoc, scalable, dual-head PET prototype for in-beam treatment planning verification of the proton therapy. In this paper we report the first results obtained with our current prototype, consisting of two opposing lutetium yttrium orthosilicate (LYSO) detectors, each one covering an area of 4.5 x 4.5 cm². We measured the β+-activation induced by 62 MeV proton beams at Catana facility (LNS, Catania, Italy) in several plastic phantoms. Experiments were performed to evaluate the possibility to extract accurate phantom geometrical information from the reconstructed PET images. The PET prototype proved its capability of locating small air cavities in homogeneous PMMA phantoms with a submillimetric accuracy and of distinguishing materials with different 16O and 12C content by back mapping phantom geometry through the separation of the isotope contributions. This could be very useful in the clinical practice as a tool to highlight anatomical or physiological organ variations among different treatment sessions and to discriminate different tissue types, thus providing feedbacks for the accuracy of dose deposition. [ABSTRACT FROM AUTHOR]

The in-beam PET is a novel PET application to image the β+ 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 also detecting the contribution provided by the very short lived isotopes, e.g. 15O. A .compact, dedicated tomograph should then be developed for such an application, so as to be used in the treatment room. We developed a small PET prototype in order to demonstrate the feasibility of such a technique for the monitoring of proton therapy of ocular tumors at the CATANA facility (Catania, Italy). The prototype consists of two planar heads with an active area of about 5 cm × 5 cm. Each head is made up of a square position sensitive photomultiplier (Hamamatsu H8500) coupled to a matrix of the same size of LYSO scintillating crystals (2 mm × 2 mm × 18 mm pixel dimensions). Dedicated, compact electronic boards are used for the signal multiplexing, amplification and digitization. The distance between the pair can be varied from 10 cm up to a maximum of about 20 cm. The validation of the prototype was performed on plastic phantoms using 62 MeV protons at the CATANA beam line. Different dose distributions were 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. [ABSTRACT FROM AUTHOR]