Development of a Compton camera for medical applications based on silicon strip and scintillation detectors

International audienceA Compton camera is being developed for the purpose of ion-range monitoring during hadrontherapy via the detection of prompt-gamma rays. The system consists of a scintillating fiber beam tagging hodoscope, a stack of double sided silicon strip detectors (90 Â 90 Â 2 mm 3 , 2 Â 64 strips) as scatter detectors, as well as bismuth germanate (BGO) scintillation detectors (38 Â 35 Â 30 mm 3 , 100 blocks) as absorbers. The individual components will be described, together with the status of their characterization

Real-Time Online Monitoring of the Ion Range by Means of Prompt Secondary Radiations

International audiencePrompt secondary radiations such as gamma rays and protons can be used for ion-range monitoring during ion therapy either on an energy-slice basis or on a pencil-beam basis. We present a review of the ongoing activities in terms of detector developments, imaging, experimental and theoretical physics issues concerning the correlation between the physical dose and hadronic processe

Distributions of secondary particles in proton and carbon-ion therapy: a comparison between GATE/Geant4 and FLUKA Monte Carlo codes.

Monte Carlo simulations play a crucial role for in-vivo treatment monitoring based on PET and prompt gamma imaging in proton and carbon-ion therapies. The accuracy of the nuclear fragmentation models implemented in these codes might affect the quality of the treatment verification. In this paper, we investigate the nuclear models implemented in GATE/Geant4 and FLUKA by comparing the angular and energy distributions of secondary particles exiting a homogeneous target of PMMA. Comparison results were restricted to fragmentation of (16)O and (12)C. Despite the very simple target and set-up, substantial discrepancies were observed between the two codes. For instance, the number of high energy (>1 MeV) prompt gammas exiting the target was about twice as large with GATE/Geant4 than with FLUKA both for proton and carbon ion beams. Such differences were not observed for the predicted annihilation photon production yields, for which ratios of 1.09 and 1.20 were obtained between GATE and FLUKA for the proton beam and the carbon ion beam, respectively. For neutrons and protons, discrepancies from 14% (exiting protons-carbon ion beam) to 57% (exiting neutrons-proton beam) have been identified in production yields as well as in the energy spectra for neutrons

2012 Activity Report of the Regional Research Programme on Hadrontherapy for the ETOILE Center

2012 is the penultimate year of financial support by the CPER 2007-2013 for ETOILE's research program, sustained by the PRRH at the University Claude Bernard. As with each edition we make the annual review of the research in this group, so active for over 12 years now. Over the difficulties in the decision-making process for the implementation of the ETOILE Center, towards which all our efforts are focussed, some "themes" (work packages) were strengthened, others have progressed, or have been dropped. This is the case of the eighth theme (technological developments), centered around the technology for rotative beam distribution heads (gantries) and, after being synchronized with the developments of ULICE's WP6, remained so by ceasing its activities, coinciding also with the retirement of its historic leader at IPNL, Marcel Bajard. Topic number 5 ("In silico simulations") has suffered the departure of its leader, Benjamin Ribba, although the work has still been provided by Branka Bernard, a former postdoctoral fellow in Lyon Sud, and now back home in Croatia, still in contract with UCBL for the ULICE project. Aside from these two issues (and the fact that the theme "Medico-economical simulations" is now directly linked to the first one ("Medical Project"), the rest of the teams are growing, as evidenced by the publication statistics at the beginning of this report. This is obviously due to the financial support of our always faithful regional institutions, but also to the synergy that the previous years, the European projects, the arrival of the PRIMES LabEx, and the national France Hadron infrastructure have managed to impulse. The Rhone-Alpes hadron team, which naturally includes the researchers of LPC at Clermont, should also see its influence result in a strong presence in France Hadron's regional node, which is being organized. The future of this regional research is not yet fully guaranteed, especially in the still uncertain context of ETOILE, but the tracks are beginning to emerge to allow past and present efforts translate into a long future that we all want to see established. Each of the researchers in PRRH is aware that 2013 will be (and already is) the year of great challenge : for ETOILE, for the PRRH, for hadron therapy in France, for French hadrontherapy in Europe (after the opening and beginning of treatments in the German [HIT Heidelberg, Marburg], Italian [CNAO, Pavia] and Austrian [MedAustron, Wien Neuerstadt]) centers. Let us meet again in early 2014 for a comprehensive review of the past and a perspective for the future ..

Construction and first tests of a PET-like detector for hadrontherapy beam ballistic control

International audienceWe present the first results obtained with a detector, called Large Area Pixelized Detector (LAPD), dedicated to the beam ballistic control in the context of hadrontherapy. The purpose is to control the ballistics of the beam delivered to the patient by in-beam and real time detection of secondary particles, emitted during its irradiation. These particles could be high energy photons (γ prompt), or charged particles like protons, or 511 keV γ from the annihilation of a positron issued from the β+ emitters induced in the patient tissues along the beam path. These methods require being able to detect with a huge efficiency, and with a minimum dead time, these secondary particles emitted when the beam hits the patient.The LAPD is similar to a conventional Positron Emission Tomography camera. The 511 keV γ are detected and the reconstructed line of responses allow to measure the β+ activity distribution. Nevertheless, when trying to use γ from positron annihilations for the ballistic control in hadrontherapy, the large γ prompt background should be taken into account and properly rejected.This detector is made of two half-rings of 120 channels each. Each channel consists of a 13*13*15 mm3 LYSO crystal glued to a PMT. The PMT signal is sent to an Analog Sampling Module (ASM board). This VME 6U board is based on the DRS4 chip technology (Switch Capacitor Array) from the Paul Sherrer Institute and was specially designed for the LAPD detector. This board receives up to 24 differential analog input signals, with maximum amplitude of 600 mV, digitized by 12 bits - 33 MHz ADC. The sampling rate varies between 1 and 5 GHz, for a maximum buffer size of 1024 samples.The first part of the talk is devoted to the description of the detector and its electronics. Then, we describe the various trigger strategy, and the on-going upgrade of the VME-based acquisition system to a μTCA-based technology. The selection of the coincident 511 keV γ is also discussed, and the reconstruction using an iterative MLEM algorithm is presented. In the last part of the talk, few results from an experiment with one third of the detector, using proton and carbon ion beams at the Heidelberg Ion-Beam Therapy Center in 2014, are also described, and the Coincidence Resolution Time and energy resolution are given. First reconstruction results, obtained with a phantom filled with a high intensity FDG source at the cancer research center of Clermont- Ferrand in 2015 are also shown.This detector is now characterized, and will be installed at the Lacassagne hadrontherapy center (Nice, France), on the 65 MeV line (Medicyc) in December 2015 first, and on the future 230 MeV line (S2C2 from IBA) in 2016. The capability of this detector and its associated electronics to measure the ballistic of the proton beam in real clinical conditions with a sufficient precision will be evaluated

Construction and tests of an in-beam PET-like demonstrator for hadrontherapy beam ballistic control

International audienc

Online control of the beam range during Hadrontherapy

International audienceOne of the advantages of hadrontherapy with respect to conventional radiotherapy is the fact that ions deposit a large fraction of their dose at the end of their path (Bragg peak), which allows a maximization of the dose to the tumor and a minimization in haelthy tissues. The lateral dose distribution is also quite narrow. Another advantage is the higher relative biological effectiveness. Due to sharp falloff, one of the major issues for quality control during the treatment with ion beams is the control of the Bragg peak position and its conformation to the tumor volume. A mispositioning would lead to an over-dosage of healthy tissue and/ or an under-dosage in the target volume.Since no primary radiation is emerging from the patient during traetment, secondary radiation arising from nuclear reactions is used for in vivo monitoring purposes. Several types of radiation are being investigated in the frame of WP1 of the LabEx PRIMES and WP4 of France Hadron:- the detection of the two 511 KeV gammas following a beta+ decay via a PET scanner,- prompt secondary radiation following inelastic nuclear interactions, either prompt gamma rays via a collimated gamma or Compton camera, or secondary proton vertex imaging.Proton radiography and computed tomography (CT) is also under investigation for quality assurance prior to the irradiation: this could reduce the uncertainty of the proton therapy planning due to the lack of accuracy in the proton stopping power of tissues computed from photon CT images

Monte Carlo Simulations of Prompt-Gamma Emission During Carbon Ion Irradiation

accepted for publication in IEEE TNSMonte Carlo simulations based on the Geant4 toolkit (version 9.1) were performed to study the emission of secondary prompt-gamma rays produced by nuclear reactions during carbon ion-beam therapy. These simulations were performed along with an experimental program and instrumentation developments which aim at designing a prompt-gamma ray device for real-time control of hadrontherapy. The objective of the present study is twofold: firstly, to present the features of the prompt-gamma radiation in the case of carbon ion irradiation; secondly, to simulate the experimental setup and to compare measured and simulated counting rates corresponding to four different experiments. For each experiment, we found that simulations overestimate prompt-gamma ray detection yields by a factor of 12. Uncertainties in fragmentation cross sections and binary cascade model cannot explain such discrepancies. The so-called “photon evaporation” model is therefore questionable and its modification is currently in progress

Construction and tests of an in-beam PET-like demonstrator for hadrontherapy beam ballistic control

International audienceWe present the first results obtained with a detector, called Large Area Pixelized Detector (LAPD), dedicated to the study the ballistic control of the beam delivered to the patient by in-beam and real time detection of secondary particles, emitted during its irradiation in the context of hadrontherapy. These particles are 511 keV γ from the annihilation of a positron issued from the β+ emitters induced in the patient tissues along the beam path. The LAPD basic concepts are similar to a conventional PET camera. The 511 keV γ are detected and the reconstructed lines of response allow to measure the β+ activity distribution. Nevertheless, when trying to use γ from positron annihilation for the ballistic control in hadrontherapy, the large prompt γ background should be taken into account and properly rejected. First reconstruction results, obtained with a phantom filled with a high intensity FDG source at the cancer research centre of Clermont-Ferrand are shown. We also report results of measurements performed at the Heidelberg Ion-Beam Therapy Centre with one third of the detector, using proton and carbon ion beams