Use of short-lived positron emitters for in-beam and real-time β+ range monitoring in proton therapy

AIM

The purpose of this work is to evaluate the precision with which the GEANT4 toolkit simulates the production of β⁺ emitters relevant for in-beam and real-time PET in proton therapy.

BACKGROUND

An important evolution in proton therapy is the implementation of in-beam and real-time verification of the range of protons by measuring the correlation between the activity of β⁺ and dose deposition. For that purpose, it is important that the simulation of the various β⁺ emitters be sufficiently realistic, in particular for the ¹²N short-lived emitter that is required for efficient in-beam and real-time monitoring.

METHODS

The GEANT4 toolkit was used to simulate positron emitter production for a proton beam of 55 MeV in a cubic PMMA target and results are compared to experimental data.

RESULTS

The three β⁺ emitters with the highest production rates in the experimental data (¹¹C, ¹⁵O and ¹²N) are also those with the highest production rate in the simulation. Production rates differ by 8% to 174%. For the ¹²N isotope, the β⁺ spatial distribution in the simulation shows major deviations from the data. The effect of the long range (of the order of 20 mm) of the β⁺ originating from ¹²N is also shown and discussed.

CONCLUSIONS

At first order, the GEANT4 simulation of the β⁺ activity presents significant deviations from the data. The need for precise cross-section measurements versus energy below 30 MeV is of first priority in order to evaluate the feasibility of in-beam and real-time PET.

In-beam tests of a PET demonstrator (LAPD) for hadrontherapy beam ballistic control: data comparison to Geant4 Monte-Carlo predictions

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.

Evaluation of Single-Chip, Real-Time Tomographic Data Processing on FPGA SoC Devices

A novel approach to tomographic data processing has been developed and evaluated using the Jagiellonian positron emission tomography scanner as an example. We propose a system in which there is no need for powerful, local to the scanner processing facility, capable to reconstruct images on the fly. Instead, we introduce a field programmable gate array system-on-chip platform connected directly to data streams coming from the scanner, which can perform event building, filtering, coincidence search, and region-of-response reconstruction by the programmable logic and visualization by the integrated processors. The platform significantly reduces data volume converting raw data to a list-mode representation, while generating visualization on the fly.