This paper describes a small prototype of an in beam PET like detector, named ”Large Acceptance Pixelized Detector” (LAPD), developed to test technical concepts for the ion range control in the ...context of cancer treatments using proton or ion beams. The mechanical characteristics of this detector together with the read-out electronics are first presented. Then, results of a first experiment, performed on a 65 MeV proton beamline, are reported. Finally, we discuss the ability of Geant4 Monte-Carlo to reproduce the experimental data.
A software tool, computing observed and expected upper limits on Poissonian process rates using a hybrid frequentist-Bayesian CLs method, is presented. This tool can be used for simple counting ...experiments where only signal, background and observed yields are provided or for multi-bin experiments where binned distributions of discriminating variables are provided. It allows the combination of several channels and takes into account statistical and systematic uncertainties, as well as correlations of systematic uncertainties between channels. It has been validated against other software tools and analytical calculations, for several realistic cases.
Program Title:OpTHyLiC
Program Files doi:http://dx.doi.org/10.17632/2jv8ytrhcg.1
Licensing provisions: GPLv3
Programming language: C++
Supplementary material:http://opthylic.in2p3.fr
Nature of problem: computation of limits on Poissonian process rates in presence of background when no signal is observed, taking correctly into account statistical and systematic uncertainties, in particular correlations of systematic uncertainties between samples and channels.
Solution method: a C++ library to be used together with the ROOT C++ package, using a hybrid frequentist-Bayesian CLs method; the optimisation of the program typically reduces the limit computation time down to less than a few minutes in realistic cases.
Additional comments including Restrictions and Unusual features: the ROOT software is necessary.
The effect of the intrinsic lutetium radioactivity on the detection performances of a LYSO based in-beam PET prototype used for quality control of hadron therapy treatments is studied. This ...radioactivity leads to a background that degrades the measurement of the \(\beta\) + signal. In particular, it prevents the measurement of faint signals originating from low activity \(\beta\) + sources. This paper presents a method to estimate the minimum \(\beta\) + activity that can be measured for any acquisition time taking into account the non-extensible dead time of the detector. This method is illustrated with experimental data collected with the in-beam PET prototype. The results presented in this paper are therefore specific to this detector. The method can however be applied in other contexts, either to other lutetium based PET detectors or even to non-PET detectors affected by lutetium radioactivity. The dead time correction formalism can also be used generally to scale signal and background yields in any non-paralizable detector, even those in which the background is not due to the presence of intrinsic radioactivity.
The relation between hybrid CLs and bayesian methods used for limit setting is discussed. It is shown that the two methods are equivalent in the single channel case even when the background yield is ...not perfectly known. Only counting experiments are considered in this document.
A software tool, computing observed and expected upper limits on Poissonian process rates using a hybrid frequentist-Bayesian CLs method, is presented. This tool can be used for simple counting ...experiments where only signal, background and observed yields are provided or for multi-bin experiments where binned distributions of discriminating variables are provided. It allows the combination of several channels and takes into account statistical and systematic uncertainties, as well as correlations of systematic uncertainties between channels. It has been validated against other software tools and analytical calculations, for several realistic cases.
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