Monte Carlo simulation tool for online treatment monitoring in hadrontherapy with in-beam PET: A patient study

Abstract

Hadrontherapy is a method for treating cancer with very targeted dose distributions and enhanced radiobiological effects. To fully exploit these advantages, in vivo range monitoring systems are required. These devices measure, preferably during the treatment, the secondary radiation generated by the beam-tissue interactions. However, since correlation of the secondary radiation distribution with the dose is not straightforward, Monte Carlo (MC) simulations are very important for treatment quality assessment. The INSIDE project constructed an in-beam PET scanner to detect signals generated by the positron-emitting isotopes resulting from projectile-target fragmentation. In addition, a FLUKA-based simulation tool was developed to predict the corresponding reference PET images using a detailed scanner model. The INSIDE in-beam PET was used to monitor two consecutive proton treatment sessions on a patient at the Italian Center for Oncological Hadrontherapy (CNAO). The reconstructed PET images were updated every 10 s providing a near real-time quality assessment. By half-way through the treatment, the statistics of the measured PET images were already significant enough to be compared with the simulations with average differences in the activity range less than 2.5 mm along the beam direction. Without taking into account any preferential direction, differences within 1 mm were found. In this paper, the INSIDE MC simulation tool is described and the results of the first in vivo agreement evaluation are reported. These results have justified a clinical trial, in which the MC simulation tool will be used on a daily basis to study the compliance tolerances between the measured and simulated PET images.

Delivery, Beam and Range Monitoring in Particle Therapy in a Highly Innovative Integrated Design

“…The simulation tool was successfully validated both in controlled conditions (phantom tests) and in a clinical environment, providing an agreement with the data comparable to the variability of data from consecutive treatment sessions [26].…”

“…As of now, however, only few results were obtained in real time in a clinical environment with proton beams: tests on a small number of patients show that prompt gamma imaging [24] provides an accuracy in range verification that is better than the range uncertainty margin set in the treatment plans, while inbeam PET provides a range agreement within 1 mm between consecutive delivery sessions [25] and in the comparison of simulations to data [26].…”

Inter-fractional monitoring of $$^{12}$$C ions treatments: results from a clinical trial at the CNAO facility

“…The DP is integrated in the INSIDE movable cart that includes also two planar PET heads 13,14 and is placed at ∼ 50 cm from the treatment room isocenter due to the constraints set by the mechanical integration with the PET device. The DP position inside the CNAO treatment room n.1 can be seen in Fig.…”

Double-Field Hadrontherapy Treatment Monitoring With the INSIDE In-Beam PET Scanner: Proof of Concept

“…3) are then compared. The range analysis has been tested for clinical treatments delivered on PMMA phantoms and, more recently, to assess the measured activity compliance with the expected distribution in a clinical in-vivo treatment [8], [11], [16], [21], [23]. Previous studies report activity comparisons along the beam direction only, or by visual means performed by specialized personnel [10], [17], [24]- [26].…”