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https://www.readbyqxmd.com/read/28742053/submillimeter-ionoacoustic-range-determination-for-protons-in-water-at-a-clinical-synchrocyclotron
#1
Sebastian Lehrack, Walter Assmann, Damien Bertrand, Sebastien Henrotin, Joel Herault, Vincent Heymans, Francois Vander Stappen, Peter G Thirolf, Marie Vidal, Jarno Van de Walle, Katia Parodi
Proton ranges in water between 145 MeV to 227 MeV initial energy have been measured at a clinical superconducting synchrocyclotron using the acoustic signal induced by the ion dose deposition (ionoacoustic effect). Detection of ultrasound waves was performed by a very sensitive hydrophone and signals were stored in a digital oscilloscope triggered by secondary prompt gammas. The ionoacoustic range measurements were compared to existing range data from a calibrated range detector setup on-site and agreement of better than 1 millimeter was found at a dose of a few Gy, compatible with the experimental errors...
July 25, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28741749/clinical-outcomes-after-local-field-conformal-reirradiation-of-patients-with-retropharyngeal-nodal-metastasis
#2
Courtney Pollard, Theresa P Nguyen, Sweet Ping Ng, Steven J Frank, Adam S Garden, Gary B Gunn, Clifton D Fuller, Beth M Beadle, William H Morrison, Shah J Shah, He Wang, Sam Tung, Conjun Wang, Lawrence D Ginsberg, Mark E Zafereo, Erich M Sturgis, Shirley Y Su, Ehab Y Hanna, David I Rosenthal, Jack Phan
BACKGROUND: The purpose of this study was to present our experience with retropharyngeal node reirradiation using highly conformal radiotherapy (RT). METHODS: A retrospective screen of 2504 consecutively irradiated patients with head and neck malignancies between 2005 and 2015 identified 19 patients who underwent reirradiation for retropharyngeal node metastasis. Clinical and toxicity outcomes were assessed in these patients. RESULTS: Thirteen patients (68%) had squamous cell carcinoma...
July 25, 2017: Head & Neck
https://www.readbyqxmd.com/read/28740924/sociodemographic-disparities-in-the-utilization-of-proton-therapy-for-prostate-cancer-at-an-urban-academic-center
#3
Kristina D Woodhouse, Wei-Ting Hwang, Neha Vapiwala, Akansha Jain, Xingmei Wang, Stefan Both, Meera Shah, Marquise Frazier, Peter Gabriel, John P Christodouleas, Zelig Tochner, Curtiland Deville
PURPOSE: Despite increasing use, proton therapy (PT) remains a relatively limited resource. The purpose of this study was to assess clinical and demographic differences in PT use for prostate cancer compared to intensity modulated radiation therapy (IMRT) at a single institution. METHODS AND MATERIALS: All patients with low- and intermediate-risk prostate cancer (N = 633) who underwent definitive radiation therapy between 2010 and 2015 were divided into PT (n = 508) and IMRT (n = 125) comparison groups and compared using χ(2) and independent sample t tests...
April 2017: Advances in Radiation Oncology
https://www.readbyqxmd.com/read/28740917/phase-1-trial-of-preoperative-image-guided-intensity-modulated-proton-radiation-therapy-with-simultaneously-integrated-boost-to-the-high-risk-margin-for-retroperitoneal-sarcomas
#4
Thomas F DeLaney, Yen-Lin Chen, Elizabeth H Baldini, Dian Wang, Judith Adams, Shea B Hickey, Beow Y Yeap, Stephen M Hahn, Karen De Amorim Bernstein, G Petur Nielsen, Edwin Choy, John T Mullen, Sam S Yoon
PURPOSE: To conduct phase 1 and 2 trials with photon intensity modulated radiation therapy and intensity modulated proton therapy (IMPT) arms to selectively escalate the retroperitoneal sarcoma preoperative radiation dose to tumor volume (clinical target volume [CTV] 2) that is judged to be at a high risk for positive margins and aim to reduce local recurrence. We report on the IMPT study arm in phase 1. METHODS AND MATERIALS: Patients aged ≥18 years with primary or locally recurrent retroperitoneal sarcoma were treated with preoperative IMPT, 50...
January 2017: Advances in Radiation Oncology
https://www.readbyqxmd.com/read/28735379/multidisciplinary-management-of-clival-chordomas-long-term-clinical-outcome-in-a-single-institution-consecutive-series
#5
Petter Förander, Jiri Bartek, Michael Fagerlund, Hamza Benmaklouf, Ernest Dodoo, Alia Shamikh, Pär Stjärne, Tiit Mathiesen
OBJECTIVE: Chordomas of the skull base have high recurrence rates even after radical resection and adjuvant radiotherapy. We evaluate the long-term clinical outcome using multidisciplinary management in the treatment of clival chordomas. METHODS: Between 1984 and 2015, 22 patients diagnosed with an intracranial chordoma were treated at the Karolinska University Hospital, Stockholm, Sweden. Sixteen of 22 were treated with Gamma Knife radiosurgery (GKRS) for tumour residual or progression during the disease course...
July 22, 2017: Acta Neurochirurgica
https://www.readbyqxmd.com/read/28734644/postmastectomy-radiation-therapy-technique-and-cardiopulmonary-sparing-a-dosimetric-comparative-analysis-between-photons-and-protons-with-free-breathing-versus-deep-inspiration-breath-hold
#6
Sagar A Patel, Hsiao-Ming Lu, Jacqueline A Nyamwanda, Rachel B Jimenez, Alphonse G Taghian, Shannon M MacDonald, Nicolas Depauw
PURPOSE: Dosimetric studies have suggested greater cardiopulmonary sparing with protons over photons for left-sided postmastectomy radiation therapy (PMRT). Modern techniques such as deep inspiration breath hold (DIBH) can help spare the heart. This analysis compares photon and proton delivery with and without DIBH. METHODS AND MATERIALS: Ten women with left breast cancer referred for PMRT on a prospective clinical trial with unfavorable cardiac anatomy underwent free breathing (FB) and DIBH computed tomography simulation...
June 21, 2017: Practical Radiation Oncology
https://www.readbyqxmd.com/read/28727865/proton-beam-radiotherapy-and-concurrent-chemotherapy-for-unresectable-stage-iii-non-small-cell-lung-cancer-final-results-of-a-phase-2-study
#7
Joe Y Chang, Vivek Verma, Ming Li, Wencheng Zhang, Ritsuko Komaki, Charles Lu, Pamela K Allen, Zhongxing Liao, James Welsh, Steven H Lin, Daniel Gomez, Melenda Jeter, Michael O'Reilly, Ronald X Zhu, Xiaodong Zhang, Heng Li, Radhe Mohan, John V Heymach, Ara A Vaporciyan, Stephen Hahn, James D Cox
Importance: Proton beam radiotherapy (PBT) has the potential to reduce toxic effects in the definitive management of locally advanced non-small-cell lung cancer (NSCLC), but long-term prospective data are lacking. Objective: To report the final (5-year) results of a prospective study evaluating concurrent chemotherapy and high-dose PBT to treat unresectable stage III NSCLC. Design, Setting, and Participants: In this open-label, single-group assignment study, with median follow-up of 27...
July 20, 2017: JAMA Oncology
https://www.readbyqxmd.com/read/28721911/a-clarion-call-for-large-scale-collaborative-studies-of-pediatric-proton-therapy
#8
EDITORIAL
Amy Berrington de Gonzalez, Bhadrasian Vikram, Jeffrey C Buchsbaum, Florent de Vathaire, Wolfgang Dörr, Daphne Hass-Kogan, Johannes A Langendijk, Anita Mahajan, Wayne Newhauser, Andrea Ottolenghi, Cecile Ronckers, Reinhard Schulte, Linda Walsh, Torunn I Yock, Ruth A Kleinerman
No abstract text is available yet for this article.
August 1, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/28719019/initial-testing-of-a-pixelated-silicon-detector-prototype-in-proton-therapy
#9
Andrew J Wroe, Grant McAuley, Anthony V Teran, Jeannie Wong, Marco Petasecca, Michael Lerch, James M Slater, Anatoly B Rozenfeld
As technology continues to develop, external beam radiation therapy is being employed, with increased conformity, to treat smaller targets. As this occurs, the dosimetry methods and tools employed to quantify these fields for treatment also have to evolve to provide increased spatial resolution. The team at the University of Wollongong has developed a pixelated silicon detector prototype known as the dose magnifying glass (DMG) for real-time small-field metrology. This device has been tested in photon fields and IMRT...
July 18, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28700348/mechanisms-of-phosphenes-in-irradiated-patients
#10
REVIEW
Thibaud Mathis, Stephane Vignot, Cecila Leal, Jean-Pierre Caujolle, Celia Maschi, Martine Mauget-Faÿsse, Laurent Kodjikian, Stéphanie Baillif, Joel Herault, Juliette Thariat
Anomalous visual perceptions have been reported in various diseases of the retina and visual pathways or can be experienced under specific conditions in healthy individuals. Phosphenes are perceptions of light in the absence of ambient light, occurring independently of the physiological and classical photonic stimulation of the retina. They are a frequent symptom in patients irradiated in the region of the central nervous system (CNS), head and neck and the eyes. Phosphenes have historically been attributed to complex physical phenomena such as Cherenkov radiation...
June 28, 2017: Oncotarget
https://www.readbyqxmd.com/read/28696514/modulation-of-lateral-positions-of-bragg-peaks-via-magnetic-fields-inside-cancer-patients-towards-magnetic-field-modulated-proton-therapy
#11
Wencheng Shao, Xiaobin Tang, Yanling Bai, Changran Geng, Diyun Shu, Chunhui Gong, Da Chen
PURPOSE: This work investigated whether the Bragg peak (BP) positions of proton beams can be modulated to produce uniform doses and cover a tumor under the magnetic fields inside cancer patients, and whether magnetic field modulated proton therapy (MMPT) is effective in vital organ protection. METHODS: The authors initially constructed an ideal water phantom comprising a central tumor surrounded by cuboid organ regions using GEANT4. Second, we designed the proton beams passing through the gap between two adjacent organ regions during beam configuration...
July 11, 2017: Medical Physics
https://www.readbyqxmd.com/read/28691010/management-of-chordoma-and-chondrosarcoma-with-fractionated-stereotactic-radiotherapy
#12
Harish N Vasudevan, David R Raleigh, Julian Johnson, Adam A Garsa, Philip V Theodosopoulos, Manish K Aghi, Christopher Ames, Michael W McDermott, Igor J Barani, Steve E Braunstein
OBJECTIVE: To evaluate the efficacy and toxicity of fractionated stereotactic radiotherapy (FSRT) for chordoma and chondrosarcoma. METHODS: Twenty consecutive patients with a histopathologic diagnosis of chordoma (n = 16) or chondrosarcoma (n = 4) treated between 2010 and 2016 were retrospectively identified. All patients underwent FSRT in five fractions to a median dose of 37.5 Gy (range: 25-40 Gy) and followed with serial magnetic resonance imaging...
2017: Frontiers in Surgery
https://www.readbyqxmd.com/read/28681976/mixed-integer-programming-with-dose-volume-constraints-in-intensity-modulated-proton-therapy
#13
Pengfei Zhang, Neng Fan, Jie Shan, Steven E Schild, Martin Bues, Wei Liu
BACKGROUND: In treatment planning for intensity-modulated proton therapy (IMPT), we aim to deliver the prescribed dose to the target yet minimize the dose to adjacent healthy tissue. Mixed-integer programming (MIP) has been applied in radiation therapy to generate treatment plans. However, MIP has not been used effectively for IMPT treatment planning with dose-volume constraints. In this study, we incorporated dose-volume constraints in an MIP model to generate treatment plans for IMPT...
July 6, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28675582/optimization-of-dual-energy-ct-acquisitions-for-proton-therapy-using-projection-based-decomposition
#14
Gloria Vilches-Freixas, Jean Michel Létang, Nicolas Ducros, Simon Rit
PURPOSE: Dual-energy computed tomography (DECT) has been presented as a valid alternative to single-energy CT to reduce the uncertainty of the conversion of patient CT numbers to proton stopping power ratio (SPR) of tissues relative to water. The aim of this work was to optimize DECT acquisition protocols from simulations of X-ray images for the treatment planning of proton therapy using a projection-based dual-energy decomposition algorithm. METHODS: We have investigated the effect of various voltages and tin filtration combinations on the SPR map accuracy and precision, and the influence of the dose allocation between the low energy (LE) and the high energy (HE) acquisitions...
July 4, 2017: Medical Physics
https://www.readbyqxmd.com/read/28675445/europium-155-as-a-source-for-dual-energy-cone-beam-computed-tomography-in-adaptive-proton-therapy-a-simulation-study
#15
Jiahua Zhu, Scott N Penfold
PURPOSE: To investigate the feasibility of a 3D imaging system utilizing a (155) Eu source and pixelated cadmium-zinc-telluride (CZT) detector for applications in adaptive radiotherapy. Specifically, to compare the reconstructed stopping power ratio (SPR) values of a head phantom obtained with the proposed imaging technique with theoretical SPR values. METHOD: A Geant4 Monte Carlo simulation was performed with the novel imaging system. The simulation was repeated with a typical 120 kV X-ray tube spectrum while maintaining all other parameters...
July 4, 2017: Medical Physics
https://www.readbyqxmd.com/read/28665491/feasibility-of-dynamic-adaptive-passive-scattering-proton-therapy-with-computed-tomography-image-guidance-in-the-lung
#16
Shunsuke Moriya, Hidenobu Tachibana, Kenji Hotta, Naoki Nakamura, Sakae Takeji, Tetsuo Akimoto
PURPOSE: Hypo-fractionated proton beam therapy (PBT) is an approach that has been increasingly explored over the past decade. It requires high geometric accuracy for targeting of the PBT beams. However, image-guided PBT is currently commonly performed with kV X-ray images of bony anatomy. A dynamic adaptive passive scattering PBT system using computed tomography-based three-dimensional image guidance was developed, and its effectiveness was then evaluated retrospectively in patients with non-small cell lung cancer (NSCLC)...
June 30, 2017: Medical Physics
https://www.readbyqxmd.com/read/28657550/pre-treatment-patient-specific-stopping-power-by-combining-list-mode-proton-radiography-and-x-ray-ct
#17
Charles-Antoine Collins-Fekete, Sébastien Brousmiche, David C Hansen, Luc Beaulieu, Joao Seco
The relative stopping power (RSP) uncertainty is the largest contributor to the range uncertainty in proton therapy. The purpose of this work was to develop a systematic method that yields accurate and patient-specific RSPs by combining 1) pre-treatment X-ray CT and 2) daily proton radiography of the patient. The method was formulated as a penalized least squares optimization problem (<i>argmin</i>(|<b>A</b><b>x</b>-<b>b</b>|<sub>2</sub><sup>2</sup>))...
June 28, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28654202/socioeconomic-factors-affect-the-selection-of-proton-radiation-therapy-for-children
#18
Colette J Shen, Chen Hu, Matthew M Ladra, Amol K Narang, Craig E Pollack, Stephanie A Terezakis
BACKGROUND: Proton radiotherapy remains a limited resource despite its clear potential for reducing radiation doses to normal tissues and late effects in children in comparison with photon therapy. This study examined the impact of race and socioeconomic factors on the use of proton therapy in children with solid malignancies. METHODS: This study evaluated 12,101 children (age ≤ 21 years) in the National Cancer Data Base who had been diagnosed with a solid malignancy between 2004 and 2013 and had received photon- or proton-based radiotherapy...
June 27, 2017: Cancer
https://www.readbyqxmd.com/read/28649976/efficiency-of-analytical-and-sampling-based-uncertainty-propagation-in-intensity-modulated-proton-therapy
#19
N Wahl, P Hennig, H P Wieser, M Bangert
The sensitivity of intensity-modulated proton therapy (IMPT) treatment plans to uncertainties can be quantified and mitigated with robust/min-max and stochastic/probabilistic treatment analysis and optimization techniques. Those methods usually rely on sparse random, importance, or worst-case sampling. Inevitably, this imposes a trade-off between computational speed and accuracy of the uncertainty propagation. Here, we investigate analytical probabilistic modeling (APM) as an alternative for uncertainty propagation and minimization in IMPT that does not rely on scenario sampling...
June 26, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28645509/a-fast-and-reliable-method-for-daily-quality-assurance-in-spot-scanning-proton-therapy-with-a-compact-and-inexpensive-phantom
#20
Nicola Bizzocchi, Francesco Fracchiolla, Marco Schwarz, Carlo Algranati
In a radiotherapy center, daily quality assurance (QA) measurements are performed to ensure that the equipment can be safely used for patient treatment on that day. In a pencil beam scanning (PBS) proton therapy center, spot positioning, spot size, range, and dose output are usually verified every day before treatments. We designed, built, and tested a new, reliable, sensitive, and inexpensive phantom, coupled with an array of ionization chambers, for daily QA that reduces the execution times while preserving the reliability of the test...
June 20, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
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