Simultaneous Measurements of Dose and Microdosimetric Spectra in a Clinical Proton Beam Using a scCVD Diamond Membrane Microdosimeter.

Oluwasayo Loto,Izabella Zahradnik,Amelia Maia Leite,Ludovic De Marzi,Dominique Tromson,Michal Pomorski

doi:10.3390/s21041314

Abstract

A single crystal chemical vapor deposition (scCVD) diamond membrane-based microdosimetric system was used to perform simultaneous measurements of dose profile and microdosimetric spectra with the Y1 proton passive scattering beamline of the Center of Proton Therapy, Institute Curie in Orsay, France. To qualify the performance of the set-up in clinical conditions of hadrontherapy, the dose, dose rate and energy loss pulse-height spectra in a diamond microdosimeter were recorded at multiple points along depth of a water-equivalent plastic phantom. The dose-mean lineal energy () values were computed from experimental data and compared to silicon on insulator (SOI) microdosimeter literature results. In addition, the measured dose profile, pulse height spectra and values were benchmarked with a numerical simulation using TOPAS and Geant4 toolkits. These first clinical tests of a novel system confirm that diamond is a promising candidate for a tissue equivalent, radiation hard, high spatial resolution microdosimeter in beam quality assurance of proton therapy.

Highlights

IntroductionThe use of proton beams for the treatment of cancers has gained considerable interest in recent years
Not fully integrated and miniaturized yet, here we present the first proof-of-principle of operation of the modular system in the clinical conditions of a hadrontherapy facility
The calibrated pulse-height spectra of the energy loss of protons in diamond have been benchmarked with a Geant4 simulation, showing very good agreement in terms of maximum peak positions and widths

Summary

Introduction

The use of proton beams for the treatment of cancers has gained considerable interest in recent years. This is observable from the increase in the number of proton beam centers around the world. In Europe there were 25 more proton beam centers constructed between 2009 and 2019 [1]. This is a result of the comparative advantage proton therapy offers over conventional photon radiation therapy. Like every other radiation procedure, there are some concerns around the undesirable effects of proton therapy, including necrosis of the healthy tissue in the proximity of a treated tumor and cases of secondary cancers being induced. Studies [3,4,5] have revealed the need for LET optimization to reduce any unwanted biological effects in proton therapy

Results

Discussion

Conclusion