First experimental verification of prompt gamma imaging with carbon ion irradiation.

Prompt Gamma Imaging (PGI) is a promising technique for range verification in Particle Therapy. This technique was already tested in clinical environment with a knife-edge-collimator camera for proton treatments but remains relatively unexplored for Carbon Ion Radiation Therapy (CIRT). Previous FLUKA simulations suggested that PG profile shifts could be detected in CIRT with a precision of ∼ 4 mm ([Formula: see text]) for a particle statistic equal to [Formula: see text] C-ions using a 10 × 10 cm camera.

Real-time delivered dose assessment in carbon ion therapy of moving targets.

. Real-time adaptive particle therapy is being investigated as a means to maximize the treatment delivery accuracy. To react to dosimetric errors, a system for fast and reliable verification of the agreement between planned and delivered doses is essential.

Performance of LGAD strip detectors for particle counting of therapeutic proton beams.

. The performance of silicon detectors with moderate internal gain, named low-gain avalanche diodes (LGADs), was studied to investigate their capability to discriminate and count single beam particles at high fluxes, in view of future applications for beam characterization and on-line beam monitoring in proton therapy..

Calibration method and performance of a time-of-flight detector to measure absolute beam energy in proton therapy.

Background: The beam energy is one of the most significant parameters in particle therapy since it is directly correlated to the particles' penetration depth inside the patient. Nowadays, the range accuracy is guaranteed by offline routine quality control checks mainly performed with water phantoms, 2D detectors with PMMA wedges, or multi-layer ionization chambers. The latter feature low sensitivity, slow collection time, and response dependent on external parameters, which represent limiting factors for the quality controls of beams delivered with fast energy switching modalities, as foreseen in future treatments.

Experimental Validation of a Real-Time Adaptive 4D-Optimized Particle Radiotherapy Approach to Treat Irregularly Moving Tumors.

Purpose: Treatment of locally advanced lung cancer is limited by toxicity and insufficient local control. Particle therapy could enable more conformal treatment than intensity modulated photon therapy but is challenged by irregular tumor motion, associated range changes, and tumor deformations. We propose a new strategy for robust, online adaptive particle therapy, synergizing 4-dimensional optimization with real-time adaptive beam tracking.

range verification analysis with in-beam PET data for patients treated with proton therapy at CNAO.

Morphological changes that may arise through a treatment course are probably one of the most significant sources of range uncertainty in proton therapy. Non-invasive treatment monitoring is useful to increase treatment quality. The INSIDE in-beam Positron Emission Tomography (PET) scanner performs range monitoring in proton and carbon therapy treatments at the National Center of Oncological Hadrontherapy (CNAO).

Dosimetric validation of a GPU-based dose engine for a fast in silico patient-specific quality assurance program in light ion beam therapy.

Background: With rapid evolutions of fast and sophisticated calculation techniques and delivery technologies, clinics are almost facing a daily patient-specific (PS) plan adaptation, which would make a conventional experimental quality assurance (QA) workflow unlikely to be routinely feasible. Therefore, in silico approaches are foreseen by means of second-check independent dose calculation systems possibly handling machine log-files.

Purpose: To validate the in-house developed GPU-dose engine, FRoG, for light ion beam therapy (protons and carbon ions) as a second-check independent calculation system and to integrate machine log-file analysis into the patient-specific quality assurance (PSQA) program.

Localization of anatomical changes in patients during proton therapy with in-beam PET monitoring: A voxel-based morphometry approach exploiting Monte Carlo simulations.

Purpose: In-beam positron emission tomography (PET) is one of the modalities that can be used for in vivo noninvasive treatment monitoring in proton therapy. Although PET monitoring has been frequently applied for this purpose, there is still no straightforward method to translate the information obtained from the PET images into easy-to-interpret information for clinical personnel. The purpose of this work is to propose a statistical method for analyzing in-beam PET monitoring images that can be used to locate, quantify, and visualize regions with possible morphological changes occurring over the course of treatment.

Preliminary tests of dosimetric quality and projected therapeutic outcomes of multi-phase 4D radiotherapy with proton and carbon ion beams.

. The purpose of this study was to perform preliminary pre-clinical tests to compare the dosimetric quality of two approaches to treating moving tumors with ion beams: synchronously delivering the beam with the motion of a moving planning target volume (PTV) using the recently developed multi-phase 4D dose delivery (MP4D) approach, and asynchronously delivering the ion beam to a motion-encompassing internal tumor volume (ITV) combined with rescanning..

Extension of RBE-weighted 4D particle dose calculation for non-periodic motion.

Purpose: Highly conformal scanned Carbon Ion Radiotherapy (CIRT) might permit dose escalation and improved local control in advanced stage thoracic tumors, but is challenged by target motion. Dose calculation algorithms typically assume a periodically repeating, regular motion. To assess the effect of realistic, irregular motion, new algorithms of validated accuracy are needed.

Dosimetric Validation of a System to Treat Moving Tumors Using Scanned Ion Beams That Are Synchronized With Anatomical Motion.

Purpose: The purpose of this study was to validate the dosimetric performance of scanned ion beam deliveries with motion-synchronization to heterogenous targets.

Methods: A 4D library of treatment plans, comprised of up to 10 3D sub-plans, was created with robust and conventional 4D optimization methods. Each sub-plan corresponded to one phase of periodic target motion.

Monitoring Carbon Ion Beams Transverse Position Detecting Charged Secondary Fragments: Results From Patient Treatment Performed at CNAO.

Particle therapy in which deep seated tumours are treated using C ions (Carbon Ions RadioTherapy or CIRT) exploits the high conformity in the dose release, the high relative biological effectiveness and low oxygen enhancement ratio of such projectiles. The advantages of CIRT are driving a rapid increase in the number of centres that are trying to implement such technique. To fully profit from the ballistic precision achievable in delivering the dose to the target volume an online range verification system would be needed, but currently missing.

A Modular System for Treating Moving Anatomical Targets With Scanned Ion Beams at Multiple Facilities: Pre-Clinical Testing for Quality and Safety of Beam Delivery.

Background: Quality management and safety are integral to modern radiotherapy. New radiotherapy technologies require new consensus guidelines on quality and safety. Established analysis strategies, such as the failure modes and effects analysis (FMEA) and incident learning systems have been developed as tools to assess the safety of several types of radiation therapies.

Inter-fractional monitoring of [Formula: see text]C ions treatments: results from a clinical trial at the CNAO facility.

The high dose conformity and healthy tissue sparing achievable in Particle Therapy when using C ions calls for safety factors in treatment planning, to prevent the tumor under-dosage related to the possible occurrence of inter-fractional morphological changes during a treatment. This limitation could be overcome by a range monitor, still missing in clinical routine, capable of providing on-line feedback. The Dose Profiler (DP) is a detector developed within the INnovative Solution for In-beam Dosimetry in hadronthErapy (INSIDE) collaboration for the monitoring of carbon ion treatments at the CNAO facility (Centro Nazionale di Adroterapia Oncologica) exploiting the detection of charged secondary fragments that escape from the patient.

A modular dose delivery system for treating moving targets with scanned ion beams: Performance and safety characteristics, and preliminary tests.

Purpose: The purpose of this study was to develop a modular dose-delivery system (DDS) for scanned-ion radiotherapy that mitigates against organ motion artifacts by synchronizing the motion of the beam with that of the moving anatomy.

Methods: We integrated a new motion synchronization system and an existing DDS into two centers. The modular approach to integration utilized an adaptive layer of software and hardware interfaces.

A new detector for the beam energy measurement in proton therapy: a feasibility study.

The proof of concept of a new device, capable of determining in a few seconds the energy of clinical proton beams by measuring the time of flight (ToF) of protons, is presented. The prototype consists of two thin ultra fast silicon detector (UFSD) pads, aligned along the beam direction in a telescope configuration and readout by a digitizer. The method developed for extracting the energy at the isocenter from the measured ToF, validated by Monte Carlo simulations, and the procedure used to calibrate the system are also presented and discussed in detail.

Angular distribution of neutron production by proton and carbon-ion therapeutic beams.

Carbon-ion beams are increasingly used in the clinical practice for external radiotherapy treatments of deep-seated tumors. At therapeutic energies, carbon ions yield significant secondary products, including neutrons, which may be of concern for the radiation protection of the patient and personnel. We simulated the neutron yield produced by proton and carbon-ion pencil beams impinging on a clinical phantom at three different angles: 15°, 45° and 90°, with respect to the beam axis.

Accuracy assessment of the CNAO dose delivery system in the initial period of clinical activity and impact of later improvements on delivered dose distributions.

Purpose: A retrospective analysis of the dose delivery system (DDS) performances of the initial clinical operation at CNAO (Centro Nazionale di Adroterapia Oncologica) is reported, and compared with the dose delivery accuracy following the implementation of a position feedback control.

Methods: Log files and raw data of the DDS were analyzed for every field of patients treated with protons and carbon ions between January 2012 and April 2013 (~3800 fields). To investigate the DDS accuracy, the spot positions and the number of particles per spot measured by the DDS and prescribed by the treatment planning system were compared for each field.

RIDOS: A new system for online computation of the delivered dose distributions in scanning ion beam therapy.

Purpose: To describe a new system for scanned ion beam therapy, named RIDOS (Real-time Ion DOse planning and delivery System), which performs real time delivered dose verification integrating the information from a clinical beam monitoring system with a Graphic Processing Unit (GPU) based dose calculation in patient Computed Tomography.

Methods: A benchmarked dose computation algorithm for scanned ion beams has been parallelized and adapted to run on a GPU architecture. A workstation equipped with a NVIDIA GPU has been interfaced through a National Instruments PXI-crate with the dose delivery system of the Italian National Center of Oncological Hadrontherapy (CNAO) to receive in real-time the measured beam parameters.

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

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.

Online proton therapy monitoring: clinical test of a Silicon-photodetector-based in-beam PET.

Particle therapy exploits the energy deposition pattern of hadron beams. The narrow Bragg Peak at the end of range is a major advantage but range uncertainties can cause severe damage and require online verification to maximise the effectiveness in clinics. In-beam Positron Emission Tomography (PET) is a non-invasive, promising in-vivo technique, which consists in the measurement of the β+ activity induced by beam-tissue interactions during treatment, and presents the highest correlation of the measured activity distribution with the deposited dose, since it is not much influenced by biological washout.

Characterization of a commercial scintillation detector for 2-D dosimetry in scanned proton and carbon ion beams.

Introduction: Pencil beam scanning technique used at CNAO requires beam characteristics to be carefully assessed and periodically checked to guarantee patient safety. This study aimed at characterizing the Lynx® detector (IBA Dosimetry) for commissioning and periodic quality assurance (QA) for proton and carbon ion beams, as compared to EBT3 films, currently used for QA checks.

Methods And Materials: The Lynx® is a 2-D high-resolution dosimetry system consisting of a scintillating screen coupled with a CCD camera, in a compact light-tight box.

Commissioning of the 4-D treatment delivery system for organ motion management in synchrotron-based scanning ion beams.

Purpose: The aim of this work was the commissioning of delivery procedures for the treatment of moving targets in scanning pencil beam hadrontherapy.

Methods: EBT3 films fixed to the Anzai Respiratory Phantom were exposed to carbon ion scanned homogeneous fields (E=332MeV/u). To evaluate the interplay effect, field size and flatness for 3 different scenarios were compared to static condition: gated irradiation or repainting alone and combination of both.

Quality assurance of carbon ion and proton beams: A feasibility study for using the 2D MatriXX detector.

Purpose: The quality assurance (QA) procedures in particle therapy centers with active beam scanning make extensive use of films, which do not provide immediate results. The purpose of this work is to verify whether the 2D MatriXX detector by IBA Dosimetry has enough sensitivity to replace films in some of the measurements.

Methods: MatriXX is a commercial detector composed of 32×32 parallel plate ionization chambers designed for pre-treatment dose verification in conventional radiation therapy.

Dosimetric commissioning and quality assurance of scanned ion beams at the Italian National Center for Oncological Hadrontherapy.

Purpose: To describe the dosimetric commissioning and quality assurance (QA) of the actively scanned proton and carbon ion beams at the Italian National Center for Oncological Hadrontherapy.

Methods: The laterally integrated depth-dose-distributions (IDDs) were acquired with the PTW Peakfinder, a variable depth water column, equipped with two Bragg peak ionization chambers. fluka Monte Carlo code was used to generate the energy libraries, the IDDs in water, and the fragment spectra for carbon beams.