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https://www.readbyqxmd.com/read/29152846/on-the-geud-biological-optimization-objective-for-organs-at-risk-in-photon-optimizer-of-eclipse-treatment-planning-system
#1
Antonella Fogliata, Stephen Thompson, Antonella Stravato, Stefano Tomatis, Marta Scorsetti, Luca Cozzi
Inverse planning optimization using biologically based objectives is becoming part of the intensity modulated optimization process. The performances and efficacy of the biologically based gEUD (generalized Equivalent Uniform Dose) objective implemented in the Photon Optimizer (PO) of Varian Eclipse treatment planning system have been here analyzed. gEUD is associated with the parameter a that accounts for the seriality of a structure, being higher for more serial organs. The PO was used to optimize volumetric modulated arc therapy (VMAT) plans on a virtual homogeneous cylindrical phantom presenting a target and an organ at risk (OAR)...
November 20, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29152430/a-dosimetric-comparison-of-intensity-modulated-proton-therapy-volumetric-modulated-arc-therapy-and-4%C3%AF-non-coplanar-intensity-modulated-radiation-therapy-for-a-patient-with-parameningeal-rhabdomyosarcoma
#2
Tiffany W Chen, Julian Sison, Becky Lee, Arthur J Olch, Andrew Chang, Annelise Giebeler, Kenneth Wong
Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and manifests as two major histological subtypes: embryonal and alveolar. The five-year local failure rate for RMS at parameningeal sites (middle ear, mastoid region, nasal cavity, etc.) is around 17% despite multiple Intergroup Rhabdomyosarcoma Study Group (IRS) trials conducted to determine the optimal radiation treatment regimen. This case report explores the use of intensity-modulated proton therapy (IMPT) for a 10-year-old child who presented with left eye irritation, facial pain, and headaches and was found to have an alveolar parameningeal rhabdomyosarcoma...
September 10, 2017: Curēus
https://www.readbyqxmd.com/read/29147446/evaluation-of-acute-toxicity-and-early-clinical-outcome-in-head-and-neck-cancers-treated-with-conventional-radiotherapy-and-simultaneous-integrated-boost-arc-radiotherapy
#3
Amit Bahl, Arun S Oinam, Satinder Kaur, Roshan Verma, Arun Elangovan, Sudhir Bhandari, Jaimanti Bakshi, Naresh Panda, Sushmita Ghoshal
Background: Chemoradiotherapy plays an important role in management of locally advanced head and neck cancers. This retrospective analysis was done to evaluate and compare acute toxicity profiles and early clinical outcomes in patients treated with conventional and arc techniques. Methods: Fifty-five patients of head and neck cancers were evaluated. Thirty patients received conventional radiotherapy with 6 MV or cobalt 60 and 25 patients were treated with simultaneous integrated boost-volumetric modulated arc radiotherapy (SIB-VMAT) with dose prescription of 66 - 70 Gy...
August 2017: World Journal of Oncology
https://www.readbyqxmd.com/read/29145140/fluoxetine-modulates-the-transcription-of-genes-involved-in-serotonin-dopamine-and-adrenergic-signalling-in-zebrafish-embryos
#4
V Cunha, P Rodrigues, M M Santos, P Moradas-Ferreira, M Ferreira
Neurotransmitters pathways in fish and mammals are phylogenetically conserved. Therefore, the environmental presence of psychopharmaceuticals, such as fluoxetine (FLU), are likely to interact with fish serotonergic, dopaminergic and adrenergic systems, affecting their response and associated biological functions. Hence, the present work aimed at evaluating the effects of FLU in the transcription of genes involved in serotonin, dopamine and adrenergic transporters and receptors signalling in early stages of Danio rerio development...
October 27, 2017: Chemosphere
https://www.readbyqxmd.com/read/29137808/geometric-and-dosimetric-accuracy-of-dynamic-tumor-tracking-during-volumetric-modulated-arc-therapy-using-a-gimbal-mounted-linac
#5
Tomohiro Ono, Yuki Miyabe, Kunio Takahashi, Mami Akimoto, Nobutaka Mukumoto, Yoshitomo Ishihara, Mitsuhiro Nakamura, Takashi Mizowaki, Masahiro Hiraoka
PURPOSE: The aim was to examine the feasibility of a dynamic tumor-tracking volumetric modulated arc therapy (DTT-VMAT) technique using a gimbal-mounted linac and assess its positional, mechanical and dosimetric accuracy. MATERIALS AND METHODS: DTT-VMAT was performed using a surrogated signal-based technique. The positional tracking accuracy was evaluated as the difference between the predicted and detected target positions for various wave patterns. Mechanical accuracy measurements included gantry, multileaf collimator (MLC) and gimbal positions...
November 11, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/29131812/an-improved-distance-to-dose-correlation-for-predicting-bladder-and-rectum-dose-volumes-in-knowledge-based-vmat-planning-for-prostate-cancer
#6
Phillip D H Wall, Robert L Carver, Jonas D Fontenot
The overlap volume histogram (OVH) is an anatomical metric commonly used to quantify the geometric relationship between an organ at risk (OAR) and target volume when predicting expected dose-volumes in knowledge-based planning (KBP). This work investigated the influence of additional variables contributing to variations in the assumed linear DVH-OVH correlation for the bladder and rectum in VMAT plans of prostate patients, with the goal of increasing prediction accuracy and achievability of knowledge-based planning methods...
November 13, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29129469/does-the-use-of-volumetric-modulated-arc-therapy-reduce-gastrointestinal-symptoms-after-pelvic-radiotherapy
#7
K L White, E Varrassi, J A Routledge, L H Barraclough, J E Livsey, J McLaughlin, S E Davidson
AIMS: Growing numbers of patients with cancer are surviving after treatment with pelvic radiotherapy. We evaluated the technique of volumetric modulated arc therapy (VMAT), which delivers a decreased dose to the organs at risk. We aimed to determine outcomes of this technique in terms of patient-reported acute toxicity and late effects and correlate the frequency of gastrointestinal symptoms with the volume of bowel receiving radiation dose. MATERIALS AND METHODS: Patients who were to receive VMAT for gynaecological malignancy completed patient-reported outcomes at baseline, the end of treatment, 8 weeks and 1 year...
November 9, 2017: Clinical Oncology: a Journal of the Royal College of Radiologists
https://www.readbyqxmd.com/read/29125239/hippocampal-sparing-approach-in-fractionated-stereotactic-brain-vmat-radio-therapy-a-retrospective-feasibility-analysis
#8
Maria Daniela Falco, Stefano Giancaterino, Marco D'Andrea, Ramon Gimenez De Lorenzo, Marianna Trignani, Luciana Caravatta, Clelia Di Carlo, Saide Di Biase, Albina Allajbej, Domenico Genovesi
Volumetric Modulated Arc Therapy (VMAT) techniques for fractioned stereotactic brain radiotherapy (FSBRT) can achieve highly conformal dose distribution to intracranial lesions. However, they can potentially increase the dose to hippocampus (H) causing neurocognitive toxicity during the first four months after irradiation. The purpose of this study was to assess the feasibility of hippocampal-sparing (HS) treatment plans in 22 patients with brain metastasis treated with VMAT technique. Firstly, we retrospectively analyzed hippocampal doses in all 22 VMAT original (not hippocampal-sparing, NHS) plans...
November 10, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29121945/potential-dosimetric-benefits-of-adaptive-tumor-tracking-over-the-internal-target-volume-concept-for-stereotactic-body-radiation-therapy-of-pancreatic-cancer
#9
Konstantina Karava, Stefanie Ehrbar, Oliver Riesterer, Johannes Roesch, Stefan Glatz, Stephan Klöck, Matthias Guckenberger, Stephanie Tanadini-Lang
BACKGROUND: Radiotherapy for pancreatic cancer has two major challenges: (I) the tumor is adjacent to several critical organs and, (II) the mobility of both, the tumor and its surrounding organs at risk (OARs). A treatment planning study simulating stereotactic body radiation therapy (SBRT) for pancreatic tumors with both the internal target volume (ITV) concept and the tumor tracking approach was performed. The two respiratory motion-management techniques were compared in terms of doses to the target volume and organs at risk...
November 9, 2017: Radiation Oncology
https://www.readbyqxmd.com/read/29116237/advantages-of-a-technique-using-two-50-degree-arcs-in-simultaneous-integrated-boost-radiotherapy-for-left-sidebreast-cancer
#10
Dan Xi, Yun Ding, Rui Hu, Wendong Gu, Jinming Mu, Qilin Li
This study evaluated radiotherapy techniques with 15 cases for simultaneous integrated boost to treat whole left breast and tumor bed following breast conserving surgery. Treatment plans were generated using three techniques: volumetric modulated arc therapy (VMAT) with a partial arc of 190° (1ARC), VMAT with two tangential mini-arcs of 50° each (2TARC) and intensity modulated radiation therapy with four fixed angle fields (4IMRT). Dosimetric parameters for the whole breast (Target), the boost tumor bed (Boost), and surrounding normal organs were compared...
November 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29114599/dosimetric-and-clinical-outcomes-after-volumetric-modulated-arc-therapy-for-carcinoma-of-the-thoracic-esophagus
#11
Cai Xu, Mian Xi, Ritsuko Komaki, Peter A Balter, Meilin Huang, Brian P Hobbs, Luhua Wang, Steven H Lin
Purpose: The efficiency of radiation delivery via volumetric modulated arc therapy (VMAT) is indisputable, but outcomes after VMAT for thoracic esophageal carcinoma are largely unknown. Methods and materials: We retrospectively analyzed 65 patients with thoracic esophageal cancer who received VMAT to 50.4 Gy (range, 45-50.4 Gy) with concurrent chemotherapy from November 2012 to March 2016 at a single tertiary cancer center. We then used propensity score matching to match these 65 patients with 130 other patients treated with step-and-shoot intensity modulated radiation therapy (ssIMRT) and concurrent chemotherapy...
July 2017: Advances in Radiation Oncology
https://www.readbyqxmd.com/read/29110926/study-for-reducing-lung-dose-of-upper-thoracic-esophageal-cancer-radiotherapy-by-auto-planning-volumetric-modulated-arc-therapy-vs-intensity-modulated-radiation-therapy
#12
Hua Chen, Hao Wang, Hengle Gu, Yan Shao, Xuwei Cai, Xiaolong Fu, Zhiyong Xu
This study aimed to investigate the dosimetric differences and lung sparing between volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) in the treatment of upper thoracic esophageal cancer with T3N0M0 for preoperative radiotherapy by auto-planning (AP). Sixteen patient cases diagnosed with upper thoracic esophageal cancer T3N0M0 for preoperative radiotherapy were retrospectively studied, and 3 plans were generated for each patient: full arc VMAT AP plan with double arcs, partial arc VMAT AP plan with 6 partial arcs, and conventional IMRT AP plan...
October 27, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/29103057/a-dosimetric-comparison-of-double-arc-volumetric-arc-therapy-step-shoot-intensity-modulated-radiotherapy-and-3d-crt-for-left-sided-breast-cancer-radiotherapy-after-breast-conserving-surgery
#13
Jun-Cong Mo, Jin Huang, Wen-Dong Gu, Min Gao, Zhong-Hua Ning, Jin-Ming Mu, Qi-Lin Li, Hong-Lei Pei
OBJECTIVE: To compare the dosimetric and efficiency differences for left-sided breast cancer radiotherapy after breast-conserving surgery among three different planning techniques: double-arc volumetric-modulate arc therapy (VMAT), step-shoot intensity-modulated radiotherapy (sIMRT) and three-dimensional conformal radiation therapy (3D-CRT). MATERIALS AND METHODS: A total of 17 female patients with left-sided breast cancer who underwent breast-conserving surgery were selected; the prescription doses were 50 Gy in 25 fractions...
October 23, 2017: Technology and Health Care: Official Journal of the European Society for Engineering and Medicine
https://www.readbyqxmd.com/read/29101643/dosimetric-comparison-of-3-dimensional-conformal-radiotherapy-volumetric-modulated-arc-therapy-and-helical-tomotherapy-for-postoperative-gastric-cancer-patients
#14
Cem Onal, Yemliha Dölek, Berna Akkuş Yıldırım
PURPOSE: To compare dosimetric data for the planning target volume (PTV) and organs at risk (OARs) between 3-dimensional conformal radiotherapy (3DCRT), volumetric modulated arc therapy (VMAT), and helical tomotherapy [1]. MATERIALS AND METHODS: The dosimetric data for 15 gastric cancer patients treated with 3DCRT, VMAT, or HT techniques were used. Cumulative dosimetric parameters, homogeneity index (HI), and conformal index (CI) were compared for the PTV and OARs...
November 3, 2017: Japanese Journal of Radiology
https://www.readbyqxmd.com/read/29100293/gamma-analysis-with-a-gamma-criterion-of-2-1-mm-for-stereotactic-ablative-radiotherapy-delivered-with-volumetric-modulated-arc-therapy-technique-a-single-institution-experience
#15
Jung-In Kim, Minsoo Chun, Hong-Gyun Wu, Eui Kyu Chie, Hak Jae Kim, Jin Ho Kim, Jong Min Park
To report a single-institution experience of gamma evaluations with 2%/1 mm for stereotactic ablative radiotherapy (SABR) delivered with volumetric modulated arc therapy (VMAT) technique, from January 2014 to January 2016. A total of 168 SABR VMAT plans were analyzed with a gamma criterion of 2%/1 mm, a threshold value of 10%, and a tolerance level of 90%. Of the 168 cases, four cases failed with 2%/1 mm. The average passing rate was 97.0% ± 2.5%. Three of the four failed cases showed passing rates higher than 90%, which was achieved by shifting the measuring device by 1 mm in the left-to-right or anterior-to-posterior directions...
September 29, 2017: Oncotarget
https://www.readbyqxmd.com/read/29094802/quantification-and-comparison-the-dosimetric-impact-of-two-treatment-couch-model-in-vmat
#16
Ruohui Zhang, Yulan Gao, Wenwen Bai
The use of Monte Carlo treatment planning systems (TPS) in radiation therapy has increased the dosimetric accuracy of VMAT treatment sequences. However, this accuracy is compromised by not including the treatment couch into the treatment planning process. Therefore, the impact of the treatment couch on radiation delivery output was determined, and two different couch models (uniform couch model A vs two components model B) were included and tested in the Monaco TPS to investigate which model can better quantify the couch influence on radiation dose...
November 2, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29094419/dynamic-collimator-trajectory-algorithm-for-multiple-metastases-dynamic-conformal-arc-treatment-planning
#17
R Lee MacDonald, Christopher G Thomas, Alasdair Syme
PURPOSE: To develop an algorithm for dynamic collimator positioning to optimize beam's-eye-view (BEV) fitting of targets in dynamic conformal arc (DCA) based radiotherapy procedures, of particular use in multiple metastases stereotactic radiosurgery procedures. METHODS: A trajectory algorithm was developed to dynamically modify the angle of the collimator as a function of arc-based control point to provide optimized collimation of target volume(s). Central to this algorithm is a concept denoted herein as "whitespace" defined as any non-target area in the BEV that is not covered by any collimation system and is open to exposure from the radiation beam...
November 1, 2017: Medical Physics
https://www.readbyqxmd.com/read/29093491/dosimetric-comparison-of-the-helical-tomotherapy-volumetric-modulated-arc-therapy-and-fixed-field-intensity-modulated-radiotherapy-for-stage-iib-iiib-non-small-cell-lung-cancer
#18
Yujin Xu, Weiye Deng, Shuangyan Yang, Pu Li, Yue Kong, Ye Tian, Zhongxing Liao, Ming Chen
The study aimed to compare the dosimetric parameters to target dose coverage and the critical structures in the treatment planning of helical tomotherapy (TOMO), volumetric-modulated arc therapy (VMAT), and fixed-field intensity-modulated radiotherapy (IMRT) for NSCLC delivering conventionally fractionated radiotherapy. Thirty patients with pathologically confirmed NSCLC were included. Three radiation treatment plans were designed for each patient. All patients received the uniform prescription dose of 60 Gy to the planning target volume...
November 1, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29082594/verification-of-junction-dose-between-vmat-arcs-of-total-body-irradiation-using-a-sun-nuclear-arccheck-phantom
#19
Colm T Morrison, Kirsty L Symons, Simon J Woodings, Michael J House
A volumetric modulated arc therapy (VMAT) approach to total body irradiation (TBI) has recently been introduced at our institution. The planning target volume (PTV) is divided into separate sub-volumes, each being treated with 2 arcs with their own isocentre. Pre-treatment quality assurance of beams is performed on a Sun Nuclear ArcCHECK diode array. Measurement of junction regions between VMAT arcs with separate isocentres has previously been performed with point dose ionization chamber measurements, or with films...
October 29, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29079310/dosimetric-feasibility-of-the-hybrid-magnetic-resonance-imaging-mri-linac-system-mrl-for-brain-metastases-the-impact-of-the-magnetic-field
#20
Chia-Lin Tseng, Wietse Eppinga, Enrica Seravalli, Sara Hackett, Eric Brand, Mark Ruschin, Young K Lee, Eshetu G Atenafu, Arjun Sahgal
BACKGROUND AND PURPOSE: We aimed to investigate the suitability of treating patients with single brain metastases using stereotactic radiosurgery (SRS) with the MRL and to characterize the dosimetric impact at tissue-air interfaces resulting primarily from the electron return effect (ERE). MATERIAL AND METHODS: 24 patients treated for intact single brain metastases were analyzed. Three radiotherapy plans with the same prescribed dose were generated for each case: (1) noncoplanar volumetric modulated arc therapy (VMAT), (2) coplanar step-and-shoot intensity modulated radiotherapy (IMRT) on the MRL in the absence (MRLB=0), and (3) in the presence of the transverse magnetic field (MRLB=1...
October 24, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
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