Cross section measurements for production of positron emitters for PET imaging in carbon therapy

Abstract

International audienceIn light ion beam therapy, positron (β+) emitters are produced by the tissue nuclei through nuclear interactions with the beam ions. They can be used for the verification of the delivered dose using positron emission tomography by comparing the spatial distribution of the β+ emitters activity to a computer simulation taking into account the patient morphology and the treatment plan. However, the accuracy of the simulation greatly depends on the method used to generate the nuclear interactions producing these emitters. In the case of Monte Carlo (MC) simulations, the nuclear interaction models still lack the required accuracy due to insufficient experimental cross section data. This is particularly true for carbon therapy where literature data on fragmentation cross sections of a carbon beam with targets of medical interest are very scarce. Therefore, we performed at GANIL in July 2016 measurements on β+ emitter production cross sections with a carbon beam at 25, 50, and 95 MeV/nucleon on thin targets (C, N, O, and PMMA). We extracted the production cross section of C10,11, N13, and O14,15 that are essential to constrain or develop MC nuclear fragmentation models

Measurement of PET isotope production cross sections for protons and carbon ions on carbon and oxygen targets for applications in particle therapy range verification

“…The 10 C reference data are from Salvador et al (2017). The 11 C reference data are from Smith et al (1983), Yashima et al (2003Yashima et al ( , 2004 and Salvador et al (2017). The dashed lines mark the FLUKA calculated thresholds for the 10 C and 11 C production reactions.…”

Geant4 systematic study of the FRACAS apparatus for hadrontherapy cross section measurements

“…A significant proportion of the low fragment identification efficiencies are due to a wrong charge identification. For example at 300 MeV/nucleon the 10 Be was identified for 5% as 8 Li and for 3% as 7 Li which drops its identification efficiency down to 91%. Yet most of those low identification efficiencies concern fragments with a low production rate, while, on the opposite, the most produced fragments are globally well identified.…”

“…The particle mass identification will be obtained through its magnetic rigidity measured with a set of tracking detectors (also referred as trackers) associated to a large acceptance deflecting magnet. The use of these two simple methods in the case of a mass spectrometer has been proven to be the most accurate identification method for ions with kinetic energies in the range from 150 MeV/nucleon to 400 MeV/nucleon [6,8] considering the high probability of particle fragmentation in thick calorimeter-like detectors.…”

Timing performances of a Time-Of-Flight detection system for the FRACAS large acceptance mass spectrometer

“…C, H, O, N and Ca). While particle identification may be achieved using several well-known technique such as the range [6][7][8], Bragg peak amplitude measurements [9], ∆E -E [10] or even pulse-shape discrimination analysis [11,12], a time-of-flight spectrometer [13,14] proved to be the most accurate detection system for ions with kinetic energies higher than 150 MeV/nucleon [15,16].…”