INSIDE in-beam positron emission tomography system for particle range monitoring in hadrontherapy.

Maria Giuseppina Bisogni,Eleftheria Kostara,Elisa Fiorina,Giancarlo Sportelli,Piergiorgio Cerello,Maria Antonietta Piliero,Nicola Belcari,N Camarlinghi ,G Giraudo ,A Rivetti ,S Coli ,F Pennazio ,G Battistoni ,P Sala ,M Rolo ,A Attili ,G Pirrone ,M Morrocchi ,V Ferrero ,A Del Guerra ,V Rosso ,C Peroni ,A Ferrari ,R Wheadon

doi:10.1117/1.jmi.4.1.011005

Abstract

The quality assurance of particle therapy treatment is a fundamental issue that can be addressed by developing reliable monitoring techniques and indicators of the treatment plan correctness. Among the available imaging techniques, positron emission tomography (PET) has long been investigated and then clinically applied to proton and carbon beams. In 2013, the Innovative Solutions for Dosimetry in Hadrontherapy (INSIDE) collaboration proposed an innovative bimodal imaging concept that combines an in-beam PET scanner with a tracking system for charged particle imaging. This paper presents the general architecture of the INSIDE project but focuses on the in-beam PET scanner that has been designed to reconstruct the particles range with millimetric resolution within a fraction of the dose delivered in a treatment of head and neck tumors. The in-beam PET scanner has been recently installed at the Italian National Center of Oncologic Hadrontherapy (CNAO) in Pavia, Italy, and the commissioning phase has just started. The results of the first beam test with clinical proton beams on phantoms clearly show the capability of the in-beam PET to operate during the irradiation delivery and to reconstruct on-line the beam-induced activity map. The accuracy in the activity distal fall-off determination is millimetric for therapeutic doses.

Highlights

Hadrontherapy is a cancer therapy performed with ions for the treatment of solid and radioresistant tumors located in the vicinity of critical organs.[1,2] Its effectiveness derives mainly from the characteristic deposition of the dose that can be determined with submillimeter accuracy by calculating the position of the so-called Bragg peak (BP), that is the region with maximum dose delivered to the tissues
This paper focuses on the Innovative Solutions for Dosimetry in Hadrontherapy (INSIDE) in-beam positron emission tomography (PET) system design and construction and reports the first results achieved in view of its clinical validation
More details can be found in Ref. 26, in which we report on the Monte Carlo validation on a previous experimental set-up comprehending a small-scale prototype of the INSIDE PET system and polymethyl methacrylate (PMMA) phantoms irradiated by monoenergetic pencil beams of 68 and 72 MeV

Summary

Introduction

Hadrontherapy is a cancer therapy performed with ions (mostly protons and carbon ions) for the treatment of solid and radioresistant tumors located in the vicinity of critical organs.[1,2] Its effectiveness derives mainly from the characteristic deposition of the dose that can be determined with submillimeter accuracy by calculating the position of the so-called Bragg peak (BP), that is the region with maximum dose delivered to the tissues. Range uncertainties can be caused by errors in the stopping power calibration from the planning computed tomography (CT), physiological changes in the patient morphology, or errors in positioning the patient in the treatment room.[3] In clinical practice, range uncertainties are taken into account, allowing large safety margins (up to 3% þ3 mm in proton therapy) around the tumor and avoiding the beam directions along which the BP would be too close to critical organs.[4] In order to fully exploit the advantages of ion therapy, an in-vivo monitoring of the particle range is highly recommended

Objectives

Methods

Results

Conclusion