Publications by authors named "Antonio Carlino"

7 Publications

  • Page 1 of 1

Carbon Ion Dose Constraints in the Head and Neck and Skull Base: Review of MedAustron Institutional Protocols.

Int J Part Ther 2021 25;8(1):25-35. Epub 2021 Jun 25.

MedAustron Ion Therapy Center, Wiener Neustadt, Austria.

Background: Dose constraints are of paramount importance for the outcome of any radiotherapy treatment. In this article, we report dose-volume constraints as well as currently used fractionation schedules for carbon ion radiotherapy as applied in MedAustron (Wiener Neustadt, Austria).

Materials And Methods: For fractionation schedules, both German and Japanese regimes were used. From the clinical experience of National Institute of Radiological Sciences (Chiba, Japan) and Heidelberg Ion Therapy (Heidelberg, Germany; formerly GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany) and the work by colleagues in Centro Nazionale Adroterapia Oncologica (Pavia, Italy) recalculating the dose from the microdosimetric kinetic model to the local effect model, we have set the dose constraints for critical organs of the head and neck area. Where no clinical data was available, an educated guess was made, based on data available from photon and proton series.

Results: We report the constraints for the optic nerve and chiasm, brainstem, spinal cord, cochlea, brain parenchyma, salivary gland, eye and adnexa, and mandibular/maxillary bone; constraints are grouped based on a fractionation scheme (German versus Japanese) and the risk of toxicity (safe, low to middle, and middle to high).

Conclusion: We think validation of dose constraints should present a relevant part of the activity of any carbon ion radiotherapy facility, and we anticipate future multicentric, joint evaluations.
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http://dx.doi.org/10.14338/IJPT-20-00093.1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8270085PMC
June 2021

Results of an independent dosimetry audit for scanned proton beam therapy facilities.

Z Med Phys 2021 May 9;31(2):145-153. Epub 2021 Mar 9.

MedAustron Ion Therapy Center, Medical Physics, Wiener Neustadt, Austria.

Purpose: An independent dosimetry audit based on end-to-end testing of the entire chain of radiation therapy delivery is highly recommended to ensure consistent treatments among proton therapy centers. This study presents an auditing methodology developed by the MedAustron Ion Beam Therapy Center (Austria) in collaboration with the National Physical Laboratory (UK) and audit results for five scanned proton beam therapy facilities in Europe.

Methods: The audit procedure used a homogeneous and an anthropomorphic head phantom. The phantoms were loaded either with an ionization chamber or with alanine pellets and radiochromic films. Homogeneously planned doses of 10Gy were delivered to a box-like target volume in the homogeneous phantom and to two clinical scenarios with increasing complexity in the head phantom.

Results: For all tests the mean of the local differences of the absolute dose to water determined with the alanine pellets compared to the predicted dose from the treatment planning system installed at the audited institution was determined. The mean value taken over all tests performed was -0.1±1.0%. The measurements carried out with the ionization chamber were consistent with the dose determined by the alanine pellets with a mean deviation of -0.5±0.6%.

Conclusion: The developed dosimetry audit method was successfully applied at five proton centers including various "turn-key" Cyclotron solutions by IBA, Varian and Mevion. This independent audit with extension to other tumour sites and use of the correspondent anthropomorphic phantoms may be proposed as part of a credentialing procedure for future clinical trials in proton beam therapy.
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http://dx.doi.org/10.1016/j.zemedi.2021.01.003DOI Listing
May 2021

Beam monitor calibration of a synchrotron-based scanned light-ion beam delivery system.

Z Med Phys 2021 May 31;31(2):154-165. Epub 2020 Jul 31.

MedAustron Ion Therapy Center, Marie Curie-Straße 5, 2700 Wiener Neustadt, Austria; National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom of Great Britain and Northern Ireland, United Kingdom.

Purpose: This paper presents the implementation and comparison of two independent methods of beam monitor calibration in terms of number of particles for scanned proton and carbon ion beams.

Methods: In the first method, called the single-layer method, dose-area-product to water (DAP) is derived from the absorbed dose to water determined using a Roos-type plane-parallel ionization chamber in single-energy scanned beams. This is considered the reference method for the beam monitor calibration in the clinically relevant proton and carbon energy ranges. In the second method, called the single-spot method, DAP of a single central spot is determined using a Bragg-peak (BP) type large-area plane-parallel ionization chamber. Emphasis is given to the detailed characterization of the ionization chambers used for the beam monitor calibration. For both methods a detailed uncertainty budget on the DAP determination is provided as well as on the derivation of the number of particles.

Results: Both calibration methods agreed on average within 1.1% for protons and within 2.6% for carbon ions. The uncertainty on DAP using single-layer beams is 2.1% for protons and 3.1% for carbon ions with major contributions from the available values of k and the average spot spacing in both lateral directions. The uncertainty using the single-spot method is 2.2% for protons and 3.2% for carbon ions with major contributions from the available values of k and the non-uniformity of the BP chamber response, which can lead to a correction of up-to 3.2%. For the number of particles, an additional dominant uncertainty component for the mean stopping power per incident proton (or the CEMA) needs to be added.

Conclusion: The agreement between both methods enhances confidence in the beam monitor calibration and the estimated uncertainty. The single-layer method can be used as a reference and the single-spot method is an alternative that, when more accumulated knowledge and data on the method becomes available, can be used as a redundant dose monitor calibration method. This work, together with the overview of information from the literature provided here, is a first step towards comprehensive information on the single-spot method.
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http://dx.doi.org/10.1016/j.zemedi.2020.06.005DOI Listing
May 2021

A GATE/Geant4 beam model for the MedAustron non-isocentric proton treatment plans quality assurance.

Phys Med 2020 Mar 29;71:115-123. Epub 2020 Feb 29.

EBG MedAustron GmbH, Marie-Curie Straße 5, 2700 Wiener Neustadt, Austria.

Purpose: To present a reference Monte Carlo (MC) beam model developed in GATE/Geant4 for the MedAustron fixed beam line. The proposed model includes an absolute dose calibration in Dose-Area-Product (DAP) and it has been validated within clinical tolerances for non-isocentric treatments as routinely performed at MedAustron.

Material And Methods: The proton beam model was parametrized at the nozzle entrance considering optic and energy properties of the pencil beam. The calibration in terms of absorbed dose to water was performed exploiting the relationship between number of particles and DAP by mean of a recent formalism. Typical longitudinal dose distribution parameters (range, distal penumbra and modulation) and transverse dose distribution parameters (spot sizes, field sizes and lateral penumbra) were evaluated. The model was validated in water, considering regular-shaped dose distribution as well as clinical plans delivered in non-isocentric conditions.

Results: Simulated parameters agree with measurements within the clinical requirements at different air gaps. The agreement of distal and longitudinal dose distribution parameters is mostly better than 1 mm. The dose difference in reference conditions and for 3D dose delivery in water is within 0.5% and 1.2%, respectively. Clinical plans were reproduced within 3%.

Conclusion: A full nozzle beam model for active scanning proton pencil beam is described using GATE/Geant4. Absolute dose calibration based on DAP formalism was implemented. The beam model is fully validated in water over a wide range of clinical scenarios and will be inserted as a reference tool for research and for independent dose calculation in the clinical routine.
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http://dx.doi.org/10.1016/j.ejmp.2020.02.006DOI Listing
March 2020

Clinical implementation and commissioning of the MedAustron Particle Therapy Accelerator for non-isocentric scanned proton beam treatments.

Med Phys 2020 Feb 29;47(2):380-392. Epub 2019 Dec 29.

EBG MedAustron GmbH, Marie Curie-Straße 5, A-2700, Wiener Neustadt, Austria.

Purpose: This paper describes the clinical implementation and medical commissioning of the MedAustron Particle Therapy Accelerator (MAPTA) for non-isocentric scanned proton beam treatments.

Methods: Medical physics involvement during technical commissioning work is presented. Acceptance testing procedures, including advanced measurement methods of intra-spill beam variations, are defined. Beam monitor calibration using two independent methods based on a dose-area product formalism is described. Emphasis is given to the medical commissioning work and the specificities related to non-isocentric irradiation, since a key feature of MedAustron is the routine delivery of non-isocentric scanned proton beam treatments.

Results: Key commissioning results and beam stability trend lines for more than 2 yr of clinical operation have been provided. Intra-spill beam range, size, and position variations were within specifications of 0.3 mm, 15%, and 0.5 mm, respectively. The agreement between two independent beam monitor calibration methods was better than 1.0%. Non-isocentric treatment delivery allowed lateral penumbra reduction of up to about 30%. Daily QA measurements of the beam range, size, position, and dose were always within 1 mm, 10%, 1 mm, and 2% from the baseline data, respectively.

Conclusions: Non-isocentric treatments have been successfully implemented at MedAustron for routine scanned proton beam therapy using horizontal and vertical fixed beamlines. Up to now every patient was treated in non-isocentric conditions. The presented methodology to implement a new Scanned Ion Beam Delivery (SIBD) system into clinical routine for proton therapy may serve as a guidance for other centers.
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http://dx.doi.org/10.1002/mp.13928DOI Listing
February 2020

Evaluation of electromagnetic and nuclear scattering models in GATE/Geant4 for proton therapy.

Med Phys 2019 May 15;46(5):2444-2456. Epub 2019 Apr 15.

MedAustron Ion Therapy Centre/EBG MedAustron, Marie-Curie-Straße 5, 2700, Wiener Neustadt, Austria.

Purpose: The dose core of a proton pencil beam (PB) is enveloped by a low dose area reaching several centimeters off the central axis and containing a considerable amount of the dose. Adequate modeling of the different components of the PB profile is, therefore, required for accurate dose calculation. In this study, we experimentally validated one electromagnetic and two nuclear scattering models in GATE/Geant4 for dose calculation of proton beams in the therapeutic energy window (62-252 MeV) with and without range shifter (RaShi).

Methods: The multiple Coulomb scattering (MCS) model was validated by lateral dose core profiles measured for five energies at up to four depths from beam plateau to Bragg peak region. Nuclear halo profiles of single PBs were evaluated for three (62.4, 148.2, and 252.7 MeV) and two (97.4 and 124.7 MeV) energies, without and with RaShi, respectively. The influence of the dose core and nuclear halo on field sizes varying from 2-20 cm was evaluated by means of output factors (OFs), namely frame factors (FFs) and field size factors (FSFs), to quantify the relative increase of dose when increasing the field size.

Results: The relative increase in the dose core width in the simulations deviated negligibly from measurements for depths until 80% of the beam range, but was overestimated by up to 0.2 mm in σ toward the end of range for all energies. The dose halo region of the lateral dose profile agreed well with measurements in the open beam configuration, but was notably overestimated in the deepest measurement plane of the highest energy or when the beam passed through the RaShi. The root-mean-square deviations (RMSDs) between the simulated and the measured FSFs were less than 1% at all depths, but were higher in the second half of the beam range as compared to the first half or when traversing the RaShi. The deviations in one of the two tested hadron physics lists originated mostly in elastic scattering. The RMSDs could be reduced by approximately a factor of two by exchanging the default elastic scattering cross sections for protons.

Conclusions: GATE/Geant4 agreed satisfyingly with most measured quantities. MCS was systematically overestimated toward the end of the beam range. Contributions from nuclear scattering were overestimated when the beam traversed the RaShi or at the depths close to the end of the beam range without RaShi. Both, field size effects and calculation uncertainties, increased when the beam traversed the RaShi. Measured field size effects were almost negligible for beams up to medium energy and were highest for the highest energy beam without RaShi, but vice versa when traversing the RaShi.
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http://dx.doi.org/10.1002/mp.13472DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6850424PMC
May 2019

Implementation of dosimetry equipment and phantoms at the MedAustron light ion beam therapy facility.

Med Phys 2018 Jan 23;45(1):352-369. Epub 2017 Nov 23.

EBG MedAustron GmbH, Marie Curie-Straße 5, A-2700, Wiener Neustadt, Austria.

Purpose: To describe the implementation of dosimetry equipment and phantoms into clinical practice of light ion beam therapy facilities. This work covers not only standard dosimetry equipment such as computerized water scanners, films, 2D-array, thimble, and plane parallel ionization chambers, but also dosimetry equipment specifically devoted to the pencil beam scanning delivery technique such as water columns, scintillating screens or multilayer ionization chambers.

Method: Advanced acceptance testing procedures developed at MedAustron and complementary to the standard acceptance procedures proposed by the manufacturer are presented. Detailed commissioning plans have been implemented for each piece of dosimetry equipment and include an estimate of the overall uncertainty budget for the range of clinical use of each device. Some standard dosimetry equipment used in many facilities was evaluated in detail: for instance, the recombination of a 2D-array or the potential use of a microdiamond detector to measure reference transverse dose profiles in water in the core of the primary pencil beams and in the low-dose nuclear halo (over four orders of magnitude in dose).

Results: The implementation of dosimetry equipment as described in this work allowed determining absolute spot sizes and spot positions with an uncertainty better than 0.3 mm. Absolute ranges are determined with an uncertainty comprised of 0.2-0.6 mm, depending on the measured range and were reproduced with a maximum difference of 0.3 mm over a period of 12 months using three different devices.

Conclusion: The detailed evaluation procedures of dosimetry equipment and phantoms proposed in this work could serve as a guidance for other medical physicists in ion beam therapy facilities and also in conventional radiation therapy.
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http://dx.doi.org/10.1002/mp.12653DOI Listing
January 2018
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