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Proton beam therapy

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https://www.readbyqxmd.com/read/29054379/treatment-log-files-as-a-tool-to-identify-treatment-plan-sensitivity-to-inaccuracies-in-scanned-proton-beam-delivery
#1
Maria Francesca Belosi, Robert van der Meer, Paz Garcia de Acilu Laa, Alessandra Bolsi, Damien C Weber, Antony J Lomax
Dose distributions delivered at Gantry 2 at the Paul Scherrer Institut (PSI) can be reconstructed on the patient anatomy based on machine log files. With the present work, the dependency of the log file calculation on the planning optimization technique and on other planning parameters, such as field direction and tumour size, has been investigated. Interestingly, and despite the typically higher modulation of Intensity Modulated Proton Therapy (IMPT) plans, the results for both Single Field Uniform Distribution and IMPT approaches have been found to be similar...
October 17, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/29053837/preliminary-study-of-neutron-field-in-top-implart-proton-therapy-beam
#2
Paolo Ferrari, Monia Vadrucci, Alessandro Ampollini, Lorenzo Campani, Luigi Picardi, Concetta Ronsivalle, Francesca Mariotti
The TOP-IMPLART, a new proton therapy facility, is under development in Frascati ENEA Laboratories, near Rome. The project is centered on a medium-energy proton accelerator designed as a sequence of modular linear accelerators (the final energy will be 230 MeV). Being not a commercial product, measurements and simulation are fundamental to characterize the system and the radiation field, even during its construction. In this work some preliminary evaluations of the neutron contamination have been tried. The simulations were validated through some measurements obtaining a satisfactory agreement...
October 19, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29053110/a-method-for-acquiring-random-range-uncertainty-probability-distributions-in-proton-therapy
#3
Stacey McGowan Holloway, Max Daniel Holloway, Simon Jonathan Thomas
In treatment planning we depend upon accurate knowledge of geometric and range uncertainties. If the uncertainty model is inaccurate then the plan will produce under-dosing of the target and/or overdosing of OAR. We aim to provide a method for which centre and site-specific population range uncertainty due to inter-fraction motion can be quantified to improve the uncertainty model in proton treatment planning. Daily volumetric MVCT data from previously treated radiotherapy patients has been used to investigate inter-fraction changes to water equivalent path-length (WEPL)...
October 20, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29050953/dual-energy-ct-based-proton-range-prediction-in-head-and-pelvic-tumor-patients
#4
Patrick Wohlfahrt, Christian Möhler, Kristin Stützer, Steffen Greilich, Christian Richter
BACKGROUND AND PURPOSE: To reduce range uncertainty in particle therapy, an accurate computation of stopping-power ratios (SPRs) based on computed tomography (CT) is crucial. Here, we assess range differences between the state-of-the-art CT-number-to-SPR conversion using a generic Hounsfield look-up table (HLUT) and a direct patient-specific SPR prediction (RhoSigma) based on dual-energy CT (DECT) in 100 proton treatment fields. MATERIAL AND METHODS: For 25 head-tumor and 25 prostate-cancer patients, the clinically applied treatment plan, optimized using a HLUT, was recalculated with RhoSigma as CT-number-to-SPR conversion...
October 16, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/29049518/long-term-outcomes-after-proton-beam-irradiation-in-patients-with-large-choroidal-melanomas
#5
Thanos D Papakostas, Anne Marie Lane, Margaux Morrison, Evangelos S Gragoudas, Ivana K Kim
Importance: Although radiotherapy has been used more frequently in past decades for the management of large melanomas, long-term efficacy of proton beam irradiation (PBI) of large choroidal melanomas has not been reported. Objective: To evaluate long-term outcomes in patients who underwent PBI for the treatment of large choroidal melanomas. Design, Setting, and Participants: Data were obtained at a single Boston, Massachusetts, academic tertiary referral practice for this retrospective cohort study...
October 19, 2017: JAMA Ophthalmology
https://www.readbyqxmd.com/read/29047455/a-monte-carlo-study-to-assess-the-effect-of-1-5-t-magnetic-fields-on-the-overall-robustness-of-pencil-beam-scanning-proton-radiotherapy-plans-for-prostate-cancer
#6
Christopher Kurz, Guillaume Landry, Andreas F Resch, George Dedes, Florian Kamp, Ute Ganswindt, Claus Belka, Bas W Raaymakers, Katia Parodi
Combining magnetic-resonance imaging (MRI) and proton therapy (PT) using pencil-beam scanning (PBS) may improve image-guided radiotherapy. We aimed at assessing the impact of a magnetic field on PBS-PT plan quality and robustness. Specifically, the robustness against anatomical changes and positioning errors in an MRI-guided scenario with a 30 cm radius 1.5 T magnetic field was studied for prostate PT. Five prostate cancer patients with three consecutive CT images (CT1-3) were considered. Single-field uniform dose PBS-PT plans were generated on the segmented CT1 with Monte-Carlo-based treatment planning software for inverse optimization...
October 19, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29046789/a-retrospective-study-of-late-adverse-events-in-proton-beam-therapy-for-prostate-cancer
#7
Hirokazu Makishima, Hitoshi Ishikawa, Keiichi Tanaka, Yutaro Mori, Masashi Mizumoto, Kayoko Ohnishi, Teruhito Aihara, Nobuyoshi Fukumitsu, Toshiyuki Okumura, Hideyuki Sakurai
The efficacy and safety of proton beam therapy (PBT) were retrospectively evaluated in 111 consecutive patients with prostate cancer who underwent definitive PBT between 2008 and 2012. Following exclusion of 18 patients due to treatment suspension, loss to follow-up, and histology, the analysis included 93 patients with a median age of 68 years (range, 49-81 years). A total of 7, 32 and 54 prostate cancer patients were classified as low-, intermediate- and high-risk, respectively, as follows: High-risk, T≥3a or prostate-specific antigen (PSA) ≥20 ng/ml or Gleason Score ≥8; low-risk, T ≤2b and PSA≤10 ng/ml and Gleason Score=6; intermediate-risk, all other combinations...
October 2017: Molecular and Clinical Oncology
https://www.readbyqxmd.com/read/29045491/monte-carlo-simulation-of-secondary-neutron-dose-for-scanning-proton-therapy-using-fluka
#8
Chaeyeong Lee, Sangmin Lee, Seung-Jae Lee, Hankyeol Song, Dae-Hyun Kim, Sungkoo Cho, Kwanghyun Jo, Youngyih Han, Yong Hyun Chung, Jin Sung Kim
Proton therapy is a rapidly progressing field for cancer treatment. Globally, many proton therapy facilities are being commissioned or under construction. Secondary neutrons are an important issue during the commissioning process of a proton therapy facility. The purpose of this study is to model and validate scanning nozzles of proton therapy at Samsung Medical Center (SMC) by Monte Carlo simulation for beam commissioning. After the commissioning, a secondary neutron ambient dose from proton scanning nozzle (Gantry 1) was simulated and measured...
2017: PloS One
https://www.readbyqxmd.com/read/29040734/geometrical-efficiency-of-plane-parallel-ionization-chambers-in-proton-scanning-beam
#9
N Mojzeszek, M Klodowska, W Komenda, L Stolarczyk, R Kopec, P Olko
For commissioning of a proton therapy unit depth dose distributions must be determined and introduced into the Treatment Planning System. In pencil beam scanning (PBS) technique, integral depth dose (IDD) acquisition should be performed with detector large enough to ensure entire beam laterally broadened by scattered and secondary contributions. The purpose of this article is to quantify, using measurements and Monte Carlo transport calculations, the ionization chamber's (IC) geometrical efficiency versus the chamber radius and proton beam energy...
October 11, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29037095/biological-dose-and-complication-probabilities-for-the-rectum-and-bladder-based-on-linear-energy-transfer-distributions-in-spot-scanning-proton-therapy-of-prostate-cancer
#10
Jesper Pedersen, Jørgen B B Petersen, Camilla H Stokkevåg, Kristian S Ytre-Hauge, Stella Flampouri, Zuofeng Li, Nancy Mendenhall, Ludvig P Muren
BACKGROUND: The increased linear energy transfer (LET) at the end of the Bragg peak causes concern for an elevated and spatially varying relative biological effectiveness (RBE) of proton therapy (PT), often in or close to dose-limiting normal tissues. In this study, we investigated dose-averaged LET (LETd) distributions for spot scanning PT of prostate cancer patients using different beam angle configurations. In addition, we derived RBE-weighted (RBEw) dose distributions and related normal tissue complication probabilities (NTCPs) for the rectum and bladder...
October 17, 2017: Acta Oncologica
https://www.readbyqxmd.com/read/29036696/radiation-protection-measurements-with-the-variance-covariance-method-in-the-stray-radiation-fields-from-photon-and-proton-therapy-facilities
#11
J Lillhök, L Persson, C E Andersen, A Dasu, O Ardenfors
The microdosimetric variance-covariance method was used to study the stray radiation fields from the photon therapy facility at the Technical University of Denmark and the scanned proton therapy beam at the Skandion Clinic in Uppsala, Sweden. Two TEPCs were used to determine the absorbed dose, the dose-average lineal energy, the dose-average quality factor and the dose equivalent. The neutron component measured by the detectors at the proton beam was studied through Monte Carlo simulations using the code MCNP6...
September 29, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29034790/minimal-toxicity-after-proton-beam-therapy-for-prostate-and-pelvic-nodal-irradiation-results-from-the-proton-collaborative-group-reg001-09-trial
#12
Michael D Chuong, William Hartsell, Gary Larson, Henry Tsai, George E Laramore, Carl J Rossi, J Ben Wilkinson, Adeel Kaiser, Carlos Vargas
BACKGROUND: Proton beam therapy (PBT) reduces normal organ dose compared to intensity modulated radiation therapy (IMXT) for prostate cancer patients who receive pelvic radiation therapy. It is not known whether this dosimetric advantage results in less gastrointestinal (GI) and genitourinary (GU) toxicity than would be expected from IMXT. MATERIAL AND METHODS: We evaluated treatment parameters and toxicity outcomes for non-metastatic prostate cancer patients who received pelvic radiation therapy and enrolled on the PCG REG001-09 trial...
October 14, 2017: Acta Oncologica
https://www.readbyqxmd.com/read/29031024/use-of-a-lyso-based-compton-camera-for-prompt-gamma-range-verification-in-proton-therapy
#13
Meei-Ling Jan, Ing-Tsung Hsiao, Hsuan-Ming Huang
PURPOSE: A Compton camera (CC), which measures prompt gammas (PGs) emitted during proton therapy, is a potentially useful imaging device for proton range verification. The aim of this study is to evaluate how well the reconstructed PG images obtained from various two-stage CC configurations reproduce the distal falloff of the PG emission. METHODS: We conducted Monte Carlo simulations to evaluate different two-stage CCs positioned orthogonal to a proton pencil beam irradiating a water phantom...
October 14, 2017: Medical Physics
https://www.readbyqxmd.com/read/29029887/long-term-clinical-safety-of-high-dose-proton-radiation-therapy-delivered-with-pencil-beam-scanning-technique-for-extracranial-chordomas-and-chondrosarcomas-in-adult-patients-clinical-evidence-of-spinal-cord-tolerance
#14
Sonja Stieb, James W Snider, Lorenzo Placidi, Ulrike Kliebsch, Anthony J Lomax, Ralf A Schneider, Damien C Weber
PURPOSE: To assess the radiation dose tolerance of the spinal cord by reviewing our institutional experience regarding the incidence of radiation-induced spinal cord toxicity after high-dose pencil beam scanning proton therapy (PBSPT). METHODS AND MATERIALS: Seventy-six patients (median age 53 years; range, 23-79 years) treated for spinal chordoma (n=55) or chondrosarcoma (n=21) met the following criteria and were retrospectively analyzed: PBSPT only, no reirradiation or concomitant chemotherapy, maximum dose (Dmax) to the spinal cord of ≥45 Gy(relative biological effectiveness [RBE]), ≥18 years of age, and follow-up of ≥12 months...
September 4, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/29028221/quality-of-life-and-patient-reported-outcomes-following-proton-radiation-therapy-a-systematic-review
#15
REVIEW
Vivek Verma, Charles B Simone, Mark V Mishra
Background: As costs of cancer care rise, the importance of documenting value in oncology increases. Proton beam radiotherapy (PBT) has the potential to reduce toxicities in cancer patients, but is relatively expensive and unproven. Evaluating quality of life (QOL) and patient-reported outcomes (PROs) is essential to establishing PBT's "value" in oncologic therapy. The goal of this systematic review was to assess QOL and PROs in patients treated with PBT. Methods: Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-guided systematic searches were conducted...
April 1, 2018: Journal of the National Cancer Institute
https://www.readbyqxmd.com/read/29027014/proton-beam-therapy-or-photon-beam-radiosurgery-for-who-grade-i-meningiomas
#16
EDITORIAL
Thomas Mindermann, Andreas Mack
No abstract text is available yet for this article.
October 13, 2017: Acta Neurochirurgica
https://www.readbyqxmd.com/read/29016654/proton-beam-irradiation-inhibits-the-migration-of-melanoma-cells
#17
Katarzyna Jasińska-Konior, Katarzyna Pochylczuk, Elżbieta Czajka, Marta Michalik, Bożena Romanowska-Dixon, Jan Swakoń, Krystyna Urbańska, Martyna Elas
PURPOSE: In recent years experimental data have indicated that low-energy proton beam radiation might induce a difference in cellular migration in comparison to photons. We therefore set out to compare the effect of proton beam irradiation and X-rays on the survival and long-term migratory properties of two cell lines: uveal melanoma Mel270 and skin melanoma BLM. MATERIALS AND METHODS: Cells treated with either proton beam or X-rays were analyzed for their survival using clonogenic assay and MTT test...
2017: PloS One
https://www.readbyqxmd.com/read/28989289/epidemiology-diagnosis-and-optimal-management-of-glioma-in-adolescents-and-young-adults
#18
REVIEW
Tejan P Diwanji, Alexander Engelman, James W Snider, Pranshu Mohindra
Neoplasms of the central nervous system (CNS) are the most frequently encountered solid tumors of childhood, but are less common in adolescents and young adults (AYA), aged 15-39 years. Gliomas account for 29%-35% of the CNS tumors in AYA, with approximately two-thirds being low-grade glioma (LGG) and the remaining being high-grade glioma (HGG). We review the epidemiology, work-up, and management of LGG and HGG, focusing on the particular issues faced by the AYA population relative to pediatric and adult populations...
2017: Adolescent Health, Medicine and Therapeutics
https://www.readbyqxmd.com/read/28980978/correction-of-stopping-power-and-let-quenching-for-radiophotoluminescent-glass-dosimetry-in-therapeutic-proton-beam
#19
Weishan Chang, Yusuke Koba, Tetsurou Katayose, Keisuke Yasui, Chihiro Omachi, Masatsugu Hariu, Hidetoshi Saitoh
To measure the absorbed dose to water <i>D</i><sub>w</sub> in proton beams by radiophotoluminescent glass dosimeter (RGD), a method with the correction for the change of the mass stopping power ratio (SPR) and the linear energy transfer (LET) dependence of radiophotoluminescent (RPL) efficiency ε<sup>RGD</sup><sub>LET</sub> has been proposed. The calibration coefficient in terms of <i>D</i><sub>w</sub> for RGDs (GD-302M, Asahi Techno Glass) was obtained using a <sup>60</sup>Co γ-ray...
October 5, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28980974/analytical-probabilistic-modeling-of-rbe-weighted-dose-for-ion-therapy
#20
Hans-Peter Wieser, Philipp Hennig, Niklas Wahl, Mark Bangert
Particle therapy is especially prone to uncertainties. This issue is usually being addressed with uncertainty quantification and minimization techniques based on scenario sampling. For proton therapy, however, it was recently shown that it is also possible to use closed-form computations based on Analytical Probabilistic Modeling (APM) for this purpose. APM yields unique features compared to sampling-based approaches motivating further research in this context. This paper demonstrates the application of APM for intensity-modulated carbon ion therapy to quantify the influence of setup and range uncertainties on the RBE-weighted dose...
October 5, 2017: Physics in Medicine and Biology
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