Physica Medica: European Journal of Medical Physics - Volume 32 - Supplement 1 - February 2016

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A.178
THE INSIDE PROJECT FOR THE ON-LINE VERIFICATION OF
HADRONTHERAPY TREATMENTS: TEST RESULTS WITH A CLINICAL
PROTON BEAM
G. Pirrone *, M.A. Piliero. Department of Physics, University of Pisa and INFN
sezione di Pisa, Pisa, Italy
Introduction: Particle therapy (PT) is a promising radiotherapy tech-
nique because it offers the possibility to deliver high dose in well-defined
volumes. Treatment monitoring in PT is one of the key issues for treat-
ment quality assessment. A bimodal in-beam monitoring system for the
hadrontherapy treatments of the head and neck tumors is underway within
the INSIDE project. It is based on the detection of both the prompt radia-
tion and the back-to-back annihilation photons created during the irradiation
of the patient. In this work we present the results obtained with the first
prototype of the PET system during the irradiation of a PMMA phantom
with a 72 MeV proton beam. The irradiation was performed at the CNAO
hadrontherapy facility.
Methods and materials: The PET prototype is based on two planar detec-
tors, each composed of a pixelated LFS scintillator matrix, with 16 × 16 pixels
of 3.2 mm pitch coupled one-to-one to a matrix of multi-pixel photon-
counter array. Each detector is connected to 4 64-channel ASICs managed
by an FPGA-based read-out system. To test our system a PMMA phantom
was irradiated with a 72 MeV proton beam and the image of the β + ac-
tivity distribution was calculated through an MLEM reconstruction algorithm.
Results: The pulsed time structure of the radiation beam was easily re-
constructed and the in-spill coincidence data could be distinguished from
the inter-spill data. The inter-spill activity profile matched the profile cal-
culated with the Monte Carlo simulations. The in-spill activity image was
noisier because of higher number of random coincidences and the anni-
hilation due to the pair production of the high energy prompt photons;
however, the activity profile was still correlated with the irradiated volume.
Conclusions: The results obtained with the PET prototype were very prom-
ising. Activity spatial distribution images were reconstructed from both in-
spill and inter-spill data. This makes the system suitable for the monitoring
of the treatments at both synchrotron and cyclotron facilities.
A.179
USING ANATOMIC AND METABOLIC IMAGING IN STEREOTACTIC RADIO
NEURO-SURGERY TREATMENTS
P. Pisciotta C. Militell L. Rundo A. Stefan G. Russ S. Vitabil
M.G. Sabin C.D. Arrig F. Marletta D.D. Urso M. Ippolit M. Midir
M.C. Gilardi a Istituto di Bioimmagini e Fisiologia Molecolare – Consiglio
Nazionale delle Ricerche (IBFM-CNR), Cefalù, Italy; b Università degli Studi di
Catania, Catania, Italy; c Dipartimento di Informatica, Sistemistica e
Comunicazione (DISCo), Università degli Studi di Milano Bicocca, Milano, Italy;
d Dipartimento di Ingegneria Chimica, Gestionale, Informatica, Meccanica
(DICGIM), Palermo, Italy; e Azienda Ospedaliera per l’Emergenza Cannizzaro,
Catania, Italy; f Dipartimento di Biopatologia e Biotecnologie Mediche
(DIBIMED), Università degli Studi di Palermo, Palermo, Italy
Introduction: This study investigated the impact of biological target volume
(BTV) segmentation, using [11C]-Methionine-PET (MET-PET) images, and
the following co-registration with MR images, used to delineate the gross
target volume (GTV), in stereotactic neuro-surgery therapy. MET-PET di-
agnostic exams provide metabolic information about brain lesions. In this
way, the BTV can be used to modify the GTV in order to treat the entire
cancer region.
Nowadays, GTV is usually delineated using MR images, acquired a few hours
before treatment, using manual segmentation. However, this volume often
does not match entirely with BTV obtained using PET images. For this reason,
metabolic imaging acquires appeal and it could be used to provide addi-
tional information useful for treatment planning. Manual segmentation is
a time-expensive and operator-dependent procedure: stereotactic radio
neuro-surgery treatment effectiveness can be optimized using automatic
methods to support clinicians in the planning phase and to improve treat-
ment response assessment.
Materials and methods: Two novel semi-automatic and operator-
independent methods have been developed to segment brain lesions from
PET and MR images of 15 patients: the former based on graphs and the
latter based on clustering. The clinical target volume (CTV) is defined using
PET/MR image co-registration.
Results: The physician was assisted during the treatment-planning phase
with co-registered PET/MR images, in which the lesions have been previ-
ously segmented using the two aforementioned segmentation methods.
The treatment evaluation was executed with international criteria classi-
fication for both MR and PET.
Conclusions: Both semi-automatic segmentation methods have proved
to be a valid operator-independent instruments to identify the BTV
and the GTV in order to delineate a CTV that include metabolic and
morphologic information and useful for treatment planning and patient
follow-up.
A.180
PRELIMINARY DOSIMETRIC STUDY FOR PRECLINICAL SMALL ANIMAL
HADRONTHERAPY
P. Pisciotta G. Russo V. Marchese G.A.P. Cirrone F. Romano
D. Lami G. Cuttone M.C. Gilardi a Istituto di Bioimmagini e Fisiologia
Molecolare, Consiglio Nazionale delle Ricerche (IBFM CNR), Cefalù, PA, Italy;
b Scuola di Specializzazione in Fisica Medica, Università degli studi di Catania,
Catania, Italy; c Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del
Sud, Catania, Italy
Introduction: The development of hadrontherapy treatment techniques
evolved dramatically in the last years, producing new technologies giving
the possibility of highly conformal dose approach. In this context, pre-
clinical evaluations and study results are essential. High precision in dose
deposition measure is one of the main requirements to perform success-
ful preclinical studies.
The aim of this study was to perform a proton therapy preclinical study
at INFN-LNS in Catania.
Materials and methods: The phases followed were: the development a well-
defined dosimetric protocol, in order to achieve a high conformal dose to
the target; the design of a homemade positioning system, in order to guar-
antee a precise and consistent animal setup; the development and the
validation of a custom Geant4 application useful for irradiation treat-
ment planning of small animal. The application permits the reproduction
of CATANA (INFN-LNS) beam line geometry, of hadronic physic processes,
and the implementation of DICOM images as target obtain using a micro-
CT. So, starting from DICOM micro-CT images, our application is able to
reconstruct the real area that must be irradiated.
Results: A preclinical small animal holder was developed. A treatment sim-
ulation was executed at CATANA facility irradiating a PMMA phantom that
simulates a subcutaneous tumour in mice, using EBT3 Gafchromic films.
The dosimetric results were compared with the simulation ones using
Kolmogorov and gamma index tests.
Conclusion: An irradiation platform was realised to meet requirements of
mimicking the preclinical application of radiation therapy as closely as pos-
sible and of high conformal dose to the target, avoiding to irradiate the
surrounding healthy tissues. In addition, our Geant4 application has proved
to be a valid instrument to study dose distribution in different phantoms
with very variable geometry. This work lays the foundation to implement
interesting future in vivo studies using small animals.
A.181
IN-SILICO IMPLEMENTATION OF MRI-60CO BASED RT: A DOSIMETRICAL
COMPARISON WITH RECTAL CANCER (SIMBAD)
E. Placidi * N. Dinapoli L. Boldrini G.C. Mattiucci D. Piccari
Ma Gambacort S. Chiesa S. Teodoli V. Valentini A. Piermattei
L. Azari a UOC di Fisica Sanitaria, Fondazione Policlinico Universitario A.
Gemelli, Roma, Italy; b Divisione di Radioterapia Oncologica, Gemelli-ART,
Fondazione Policlinico Universitario A. Gemelli, Roma, Italy
Introduction: The ViewRay MRI-Co60 hybrid system (MRIdian®) allows
MRI based targeting, autosegmentation and direct planning for
e53 Abstracts/Physica Medica 32 (2016) e1–e70