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Physica Medica: PM

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https://www.readbyqxmd.com/read/30197097/beam-parameters-optimization-and-characterization-for-a-turning-linac-for-protontherapy
#1
Caterina Cuccagna, Vittorio Bencini, Stefano Benedetti, Daniele Bergesio, Pedro Carrio Perez, Enrico Felcini, Adriano Garonna, Wioletta S Kozłowska, Mohammad Varasteh Anvar, Vasilis Vlachoudis, Ugo Amaldi
TULIP (TUrning LInac for Protontherapy) is a novel compact accelerator system for protontherapy mounted on a rotating gantry (Amaldi et al., 2013, 2010, 2009). Its high-energy Linac has the unique property of being able to modulate the beam energy from one pulse to the next, in only a couple of milliseconds. The main purpose of this study is to optimize the properties of the beam exiting the Linac to make them compatible to medical therapy and to characterize their medical physics properties for later implementation in a Treatment Planning System...
September 6, 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30076107/transversal-dose-distribution-optimization-for-laser-accelerated-proton-beam-medical-applications-by-means-of-geant4
#2
G Milluzzo, J Pipek, A G Amico, G A P Cirrone, G Cuttone, G Korn, G Larosa, R Leanza, D Margarone, G Petringa, A Russo, F Schillaci, V Scuderi, F Romano
The main purpose of this paper is to quantitatively study the possibility of delivering dose distributions of clinical relevance with laser-driven proton beams. A Monte Carlo application has been developed with the Geant4 toolkit, simulating the ELIMED (MEDical and multidisciplinary application at ELI-Beamlines) transport and dosimetry beam line which is being currently installed at the ELI-Beamlines in Prague (CZ). The beam line will be used to perform irradiations for multidisciplinary studies, with the purpose of demonstrating the possible use of optically accelerated ion beams for therapeutic purposes...
July 31, 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30037452/monte-carlo-geant4-based-application-for-in-vivo-rbe-study-using-small-animals-at-lns-infn-preclinical-hadrontherapy-facility
#3
P Pisciotta, F P Cammarata, A Stefano, F Romano, V Marchese, F Torrisi, G I Forte, L Cella, G A P Cirrone, G Petringa, M C Gilardi, G Cuttone, G Russo
Preclinical studies represent an important step towards a deep understanding of the biological response to ionizing radiations. The effectiveness of proton therapy is higher than photons and, for clinical purposes, a fixed value of 1.1 is used for the relative biological effectiveness (RBE) of protons considered 1.1. Recent in vitro studies have reported that the RBE along the spread-out Bragg peak (SOBP) is not constant and, in particular, the RBE value increases on the distal part of SOBP. The present work has been carried-out in the perspective of a preclinical hadrontherapy facility at LNS-INFN and was focused on the experimental preparation of an in vivo study concerning the RBE variation along the SOBP...
July 20, 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30007841/quantum-versus-classical-monte-carlo-simulation-of-low-energy-electron-transport-in-condensed-amorphous-media
#4
Rowan M Thomson, Iwan Kawrakow
PURPOSE: Classical trajectory Monte Carlo (MC) simulations modelling radiation-induced damage on subcellular length scales ignore quantum effects that may be non-negligible as electron energy decreases below 1 keV. This work investigates quantum mechanical (QM) treatments of low-energy electron transport in condensed media, comparing with classical MC. METHODS: QM calculations involve a simplified model of electron transport in water with a plane wave incident on a cylinder ("droplet") consisting of a cluster of point scatterers (positioned randomly but constrained by a minimum separation, dmin )...
July 12, 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30017561/an-overview-of-recent-developments-in-fluka-pet-tools
#5
R S Augusto, J Bauer, O Bouhali, C Cuccagna, C Gianoli, W S Kozłowska, P G Ortega, T Tessonnier, Y Toufique, V Vlachoudis, K Parodi, A Ferrari
The new developments of the FLUKA Positron-Emission-Tomography (PET) tools are detailed. FLUKA is a fully integrated Monte Carlo (MC) particle transport code, used for an extended range of applications, including Medical Physics. Recently, it provided the medical community with dedicated simulation tools for clinical applications, including the PET simulation package. PET is a well-established imaging technique in nuclear medicine, and a promising method for clinical in vivo treatment verification in hadrontherapy...
July 2, 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30139617/multicenter-study-of-quantitative-pet-system-harmonization-using-nist-traceable-68-ge-68-ga-cross-calibration-kit
#6
Kenta Miwa, Kei Wagatsuma, Takashi Iimori, Koichi Sawada, Takashi Kamiya, Minoru Sakurai, Noriaki Miyaji, Taisuke Murata, Eisuke Sato
PURPOSE: The present study aimed to define the errors in SUV and demonstrate the feasibility of SUV harmonization among contemporary PET/CT scanners using a novel National Institute of Standards and Technology (NIST)-traceable 68 Ge/68 Ga source as the reference standard. METHODS: We used 68 Ge/68 Ga dose calibrator and PET sources made with same batch of 68 Ge/68 Ga embedded in epoxy that is traceable to the NIST standard. Bias in the amount of radioactivity and the radioactive concentrations measured by the dose calibrators and PET/CT scanners, respectively, was determined at five Japanese sites...
August 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30139616/validation-of-frame-based-positioning-accuracy-with-cone-beam-computed-tomography-in-gamma-knife-icon-radiosurgery
#7
Florian Stieler, Frederik Wenz, Beate Schweizer, Martin Polednik, Frank Anton Giordano, Sabine Mai
BACKGROUND: Frame based positioning accuracy in Gamma Knife (GK) stereotactic radiosurgery (SRS) is extremely high but removal of a post may be necessary to enable the treatment in selected patients. OBJECTIVE: To verify the positioning accuracy in clinical scenarios with 4 and 3 posts in patients and phantoms using cone-beam CT (CBCT) of Gamma Knife Icon™. METHODS: We analyzed positioning accuracy for 12 patients with standard 4 post setup using pretreatment CBCT (pre-CBCT) on GK Icon™ and report 4 patients with different clinical scenarios (removal of a post)...
August 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30139615/activity-estimation-and-biokinetic-analysis-of-99m-tc-dmsa-in-renal-infant-patients-using-a-gamma-camera
#8
P Teles, J Costa, D Costa, N Matela, P Vaz
Biokinetic data from the administration of radiopharmaceuticals is essential in nuclear medicine dosimetry. It has particular significance in children, as their metabolism is very different from adults. Biokinetic models for paediatric patients could therefore need to be adapted to better reflect their absorption, retention and excretion functions, when compared to adults. Obtaining quality in vivo infant or paediatric biokinetic data is then essential to improve the available reference models, which in turn can lead to the optimization of paediatric procedures and protocols in clinical practice...
August 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30139614/hybrid-volumetric-modulated-arc-therapy-for-chest-wall-irradiation-for-a-good-plan-get-the-right-mixture
#9
Karunakaran Balaji, Poonam Yadav, Sitaraman BalajiSubramanian, Chandrasekaran Anu Radha, Velayudham Ramasubramanian
PURPOSE: To find the optimal dose weighting for hybrid volumetric modulated arc therapy (H-VMAT), a combination of conventional 3DCRT and VMAT plans for left sided chest wall and supraclavicular radiation therapy. METHODS & MATERIALS: 20 left-sided breast cancer patients who received adjuvant radiotherapy were considered for this study. To find the optimal weighting, 5 H-VMAT plans were generated for each study case by combining different dose proportions of 3DCRT and VMAT plans including: 90% 3DCRT/10% VMAT, 80% 3DCRT/20% VMAT, 70% 3DCRT/30% VMAT, 60% 3DCRT/40% VMAT, 50% 3DCRT/50% VMAT...
August 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30139613/normal-tissue-sparing-potential-of-scanned-proton-beams-with-and-without-respiratory-gating-for-the-treatment-of-internal-mammary-nodes-in-breast-cancer-radiotherapy
#10
Alexandru Dasu, Anna M Flejmer, Anneli Edvardsson, Petra Witt Nyström
Proton therapy has shown potential for reducing doses to normal tissues in breast cancer radiotherapy. However data on the impact of protons when including internal mammary nodes (IMN) in the target for breast radiotherapy is comparatively scarce. This study aimed to evaluate normal tissue doses when including the IMN in regional RT with scanned proton beams, with and without respiratory gating. The study cohort was composed of ten left-sided breast patients CT-scanned during enhanced inspiration gating (EIG) and free-breathing (FB)...
August 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30139612/resolution-and-noise-performance-of-sparse-view-x-ray-ct-reconstruction-via-lp-norm-regularization
#11
Lin Zhang, Huijuan Zhao, Wenjuan Ma, Jingying Jiang, Limin Zhang, Jiao Li, Feng Gao, Zhongxing Zhou
OBJECTIVES: Adaptive steepest descent projection onto convex sets (ASD-POCS) algorithms with Lp-norm (0 < p ≤ 1) regularization have shown great promise in sparse-view X-ray CT reconstruction. However, the difference in p value selection can lead to varying algorithm performance of noise and resolution. Therefore, it is imperative to develop a reliable method to evaluate the resolution and noise properties of the ASD-POCS algorithms under different Lp-norm priors. METHODS: A comparative performance evaluation of ASD-POCS algorithms under different Lp-norm (0 < p ≤ 2) priors were performed in terms of modulation transfer function (MTF), noise power spectrum (NPS) and noise equivalent quanta (NEQ)...
August 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30139611/comparison-of-two-different-epid-based-solutions-performing-pretreatment-quality-assurance-2d-portal-dosimetry-versus-3d-forward-projection-method
#12
Sara Bresciani, Matteo Poli, Anna Miranti, Angelo Maggio, Amalia Di Dia, Christian Bracco, Pietro Gabriele, Michele Stasi
PURPOSE: The aim of this paper is to characterize two different EPID-based solutions for pre-treatment VMAT quality assurance, the 2D portal dosimetry and the 3D projection technique. Their ability to catch the main critical delivery errors was studied. METHODS: Measurements were performed with a linac accelerator equipped with EPID aSi1000, Portal Dose Image Prediction (PDIP), and PerFRACTION softwares. Their performances were studied simulating perturbations of a reference plan through systematic variations in dose values and micromultileaf collimator position...
August 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30139610/the-international-atomic-energy-agency-action-plan-on-radiation-protection-of-patients-and-staff-in-interventional-procedures-achieving-change-in-practice
#13
REVIEW
V Tsapaki, S Balter, C Cousins, O Holmberg, D L Miller, P Miranda, M Rehani, E Vano
INTRODUCTION: The International Atomic Energy Agency (IAEA) organized the 3rd international conference on radiation protection (RP) of patients in December 2017. This paper presents the conclusions on the interventional procedures (IP) session. MATERIAL AND METHODS: The IAEA conference was conducted as a series of plenary sessions followed by various thematic sessions. "Radiation protection of patients and staff in interventional procedures" session keynote speakers presented information on: 1) Risk management of skin injuries, 2) Occupational radiation risks and 3) RP for paediatric patients...
August 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30139609/dosimetric-analysis-of-tomotherapy-based-intracranial-stereotactic-radiosurgery-of-brain-metastasis
#14
S Agostinelli, S Garelli, M Gusinu, M Zeverino, F Cavagnetto, F Pupillo, A Bellini, G Taccini
PURPOSE: This paper analyzes Tomotherapy-based intracranial stereotactic radiosurgery (HTSRS) of brain metastasis targeting two end-points: 1) evaluation of dose homogeneity, conformity and gradient scores for single and multiple lesions and 2) assay of dosimetric criticality of completion of HTSRS procedures. METHODS: 42 treatment plans of 33 patients (53 brain lesions) treated with HTSRS were analyzed. Dose to healthy brain, homogeneity, conformity and gradient indexes were evaluated for each lesion...
August 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30139608/statistical-analysis-of-the-gamma-evaluation-acceptance-criteria-a-simulation-study-of-2d-dose-distributions-under-error-free-conditions
#15
Svjetlana Sunjic, Crister Ceberg, Tomislav Bokulic
PURPOSE: To investigate the statistical distribution of the gamma value under error-free conditions, in order to study the relation between the gamma evaluation failure rate and statistically significant deviations in the general situation. METHODS: The 2D absorbed dose distribution for 30 clinical head-and-neck IMRT fields were calculated in a QC phantom. For the same fields, dose measurements were simulated by assuming that the calculated value represented the expectation value, and by adding a random spatial uncertainty of 1-9 mm (1SD) and a random dose uncertainty of 1%-3% (1SD)...
August 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30139607/segmentation-of-parotid-glands-from-registered-ct-and-mr-images
#16
Domen Močnik, Bulat Ibragimov, Lei Xing, Primož Strojan, Boštjan Likar, Franjo Pernuš, Tomaž Vrtovec
PURPOSE: To develop an automatic multimodal method for segmentation of parotid glands (PGs) from pre-registered computed tomography (CT) and magnetic resonance (MR) images and compare its results to the results of an existing state-of-the-art algorithm that segments PGs from CT images only. METHODS: Magnetic resonance images of head and neck were registered to the accompanying CT images using two different state-of-the-art registration procedures. The reference domains of registered image pairs were divided on the complementary PG regions and backgrounds according to the manual delineation of PGs on CT images, provided by a physician...
August 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30139606/a-beam-model-for-focused-proton-pencil-beams
#17
E Almhagen, D J Boersma, H Nyström, A Ahnesjö
INTRODUCTION: We present a beam model for Monte Carlo simulations of the IBA pencil beam scanning dedicated nozzle installed at the Skandion Clinic. Within the nozzle, apart from entrance and exit windows and the two ion chambers, the beam traverses vacuum, allowing for a beam that is convergent downstream of the nozzle exit. MATERIALS AND METHODS: We model the angular, spatial and energy distributions of the beam phase space at the nozzle exit with single Gaussians, controlled by seven energy dependent parameters...
August 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30139605/scanned-carbon-ion-beam-therapy-throughput-over-the-first-7-years-at-national-institute-of-radiological-sciences
#18
Shinichiro Mori, Yuka Takei, Toshiyuki Shirai, Yousuke Hara, Takuji Furukawa, Taku Inaniwa, Katsuyuki Tanimoto, Minoru Tajiri, Daigo Kuroiwa, Taku Kimura, Naoyoshi Yamamoto, Shigeru Yamada, Hiroshi Tsuji, Tadashi Kamada
INTRODUCTION: In the 7 years since our facility opened, we have treated >2000 patients with pencil-beam scanned carbon-ion beam therapy. METHODS: To summarize treatment workflow, we evaluated the following five metrics: i) total number of treated patients; ii) treatment planning time, not including contouring procedure; iii) quality assurance (QA) time (daily and patient-specific); iv) treatment room occupancy time, including patient setup, preparation time, and beam irradiation time; and v) daily treatment hours...
August 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30139604/characterisation-of-two-new-radiochromic-gel-dosimeters-truview%C3%A2-and-clearview%C3%A2-in-combination-with-the-vista%C3%A2-optical-ct-scanner-a-feasibility-study
#19
J Colnot, C Huet, R Gschwind, I Clairand
PURPOSE: This study aims at characterising the properties of TruView™ and ClearView™ two new gel dosimeters (Modus Medical Devices Inc.) and at studying the feasibility of relative dosimetry using these dosimeters and the Vista™ Optical CT scanner to accurately evaluate dose. METHODS: In this work, we investigated key dosimetric aspects (dose response, energy and dose rate dependence) and stability of these radiochromic gels initiated in preliminary works (Huet et al...
August 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/30139603/in-vivo-epid-dosimetry-for-imrt-and-vmat-based-on-through-air-predicted-portal-dose-algorithm
#20
M A Najem, M Tedder, D King, D Bernstein, R Trouncer, C Meehan, A M Bidmead
We have adapted the methodology of Berry et al. (2012) for Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) treatments at a fixed source to imager distance (SID) based on the manufacturer's through-air portal dose image prediction algorithm. In order to fix the SID a correction factor was introduced to account for the change in air gap between patient and imager. Commissioning data, collected with multiple field sizes, solid water thicknesses and air gaps, were acquired at 150 cm SID on the Varian aS1200 EPID...
August 2018: Physica Medica: PM
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