A new PET prototype for proton therapy: comparison of data and Monte Carlo simulations

Abstract

Ion beam therapy is a valuable method for the treatment of deep-seated and radioresistant tumors thanks to the favorable depth-dose distribution characterized by the Bragg peak. Hadrontherapy facilities take advantage of the specific ion range, resulting in a highly conformal dose in the target volume, while the dose in critical organs is reduced as compared to photon therapy. The necessity to monitor the delivery precision, i.e. the ion range, is unquestionable, thus different approaches have been investigated, such as the detection of prompt photons or annihilation photons of positron emitter nuclei created during the therapeutic treatment. Based on the measurement of the induced jS + activity, our group has developed various in-beam PET prototypes: the one under test is composed by two planar detector heads, each one consisting of four modules with a total active area of 10 x 10 cm 2. A single detector module is made of a LYSO crystal matrix coupled to a position sensitive photomultiplier and is read-out by dedicated frontend electronics. A preliminary data taking was performed at the Italian National Centre for Oncological Hadron Therapy (CNAO, Pavia), using proton beams in the energy range of 93-112 MeV impinging on a plastic phantom. The measured activity profiles are presented and compared with the simulated ones based on the Monte Carlo FLUKA package.

Proton range monitoring with in-beam PET: Monte Carlo activity predictions and comparison with cyclotron data

“…More details are given in Appendix A1. As a sideremark, we mention that an increase at phantom entrance was observed also in data taken at CNAO for the energy range 93e112 MeV, where range measurements were also found to agree very well with Monte Carlo predictions [42]. This also suggests that attenuation corrections are not strictly necessary for proton range verifications.…”

“…We used a planar PET system developed at INFN (National Institute of Nuclear physics, Istituto Nazionale di Fisica Nucleare) and the University of Pisa, previously described in Refs. [15,22,42,43]. It consisted of two planar 10 Â 10 cm 2 detector heads, each composed of four modules of 5 Â 5 cm 2 each, which were placed 20 cm apart.…”

The FLUKA Code: An Accurate Simulation Tool for Particle Therapy

“…An interesting verification of FLUKA predictions against experimental data taken with a prototype PET system can be found in Ref. ( 102 ). For what concerns ion beams, the availability of experimental data on β + emitter is scarce, more would be needed to perform a careful evaluation of model predictions.…”

Nuclear physics and particle therapy

“…[17]. The proposed system consists of two planar detector heads [18] each having an area of 10×10 cm 2 based on the use of segmented scintillating LYSO crystal matrix. Measured activity results were compared with predictions from the FLUKA MC generator [19,20].…”