Sep 12 – 17, 2021
University of Birmingham
Europe/London timezone

Proton CT application in X-CT calibration for treatment planning in proton therapy

Sep 14, 2021, 3:00 PM
Teaching and Learning Building (University of Birmingham)

Teaching and Learning Building

University of Birmingham

Edgbaston Campus University of Birmingham B15 2TT UK


Monica Scaringella (INFN Firenze (IT))


Treatment planning systems for proton therapy require accurate information about stopping power ratio (SPR), relative to water, of the biological tissues the patients are made of. This information, in the present clinical practice, are extracted from X-rays computed tomography (X-CT) images. In this context the inaccuracy introduced in the conversion between Hounsfield Units (HU) and SPR maps is one of the main sources of uncertainty on the estimated proton range limiting the accuracy of treatment planning. In the recent past, in the framework of INFN funded research projects, a 5x20 cm2 field of view proton CT (pCT) system, composed of a microstrip silicon tracker and a YAG:Ce calorimeter, has been built with the aim to directly measure SPR maps. Proton tomographies of test phantoms acquired with this apparatus at Trento Proton Therapy Centre showed an accuracy on SPR measurement of about 1% (2020, Phys. Med. Biol. 65 225012). Recently a novel X-CT calibration technique, that makes use of the INFN pCT apparatus, has been proposed to improve X-CT calibration accuracy (2021, Med. Phys. 48 (3) 1349-1355). The aim of this project (XpCalib) is to prepare a set of biological phantoms and to acquire both pCT and X-CT scans on each of them by the pCT and X-CT systems to eventually extract a SPR-HU calibration function. The use of biological phantoms is proposed instead of synthetic tissue equivalent materials, which fail in accurately mimicking the real biological tissues’ properties. Another aspect that will be investigated is the possibilities to stabilize those phantoms, in order to be able to extend the calibration procedure to other proton therapy centers, even to those not equipped with a pCT scanner. In this contribution the proposed calibration method will be presented together with the main results of the pCT system.

Institute INFN Firenze (IT)
Your name Monica Scaringella
Nationality Italian

Primary authors

Carlo Civinini (INFN Firenze (IT)) Mara Bruzzi (Università di Firenze, Dipartimento di Fisica, Firenze (IT)) Monica Scaringella (INFN Firenze (IT)) Francesco Fracchiolla (Azienda Provinciale per i Servizi Sanitari APSS, Protontherapy Unit- Hospital of Trento, Trento (IT)) Francesco Tommasino (Università di Trento, Dipartimento di Fisica, Trento (IT)) Marina Scarpa (Università di Trento, Dipartimento di Fisica, Trento (IT)) Paolo Farace (Azienda Provinciale per i Servizi Sanitari (APSS), Protontherapy Unit- Hospital of Trento, Trento (IT)) Roberto Righetto (Azienda Provinciale per i Servizi Sanitari APSS, Protontherapy Unit- Hospital of Trento, Trento (IT)) Stefano Lorentini (Azienda Provinciale per i Servizi Sanitari APSS, Protontherapy Unit- Hospital of Trento, Trento (IT))

Presentation materials