44,031 results match your criteria beam radiation

Intratumoral talimogene laherparepvec injection with concurrent preoperative radiation in patients with locally advanced soft-tissue sarcoma of the trunk and extremities: phase IB/II trial.

J Immunother Cancer 2021 Jul;9(7)

Internal Medicine, The University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA.

Background: Soft-tissue sarcomas (STS) in the extremities and trunk treated with standard-of-care preoperative external beam radiation therapy (EBRT) followed by surgical resection are associated with local and distant relapses. In preclinical studies, oncolytic virotherapy in sarcoma has demonstrated antitumor effects via direct intratumoral oncolysis and cytotoxic T-cell-mediated immune responses. Talimogene laherparepvec (TVEC) is a replication-competent, immune-enhanced, oncolytic herpes simplex virus type 1 engineered for intratumoral injection; it has been approved by the FDA for the treatment of locally advanced and metastatic melanoma. Read More

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An empirical method for splitting arcs in VMAT.

Phys Med 2021 Jul 26;88:264-271. Epub 2021 Jul 26.

Department of Medical Physics, Bharathiar University, Coimbatore, India. Electronic address:

Purpose: We present a new approach to determine the optimal arc split for VMAT beams which is an extension of our recently published algorithm for selecting optimal beam angles in Intensity Modulated Radiation Therapy (IMRT) MATERIAL AND METHODS: The proposed approach uses an objective function based scoring method called "ψ - score" to determine optimal arc splitting strategy. To validate our approach, we applied it in different clinical cases: Abdomen-Para aortic node, Lung, Pancreas and Prostate. Basically, for all clinical cases, two set of plans were created, namely VMAT plan and VMAT_S plan using Pinnacle (V16. Read More

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Experimental assessment of inter-centre variation in stopping-power and range prediction in particle therapy.

Radiother Oncol 2021 Jul 27. Epub 2021 Jul 27.

OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Dresden, Germany; Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology - OncoRay, Dresden, Germany; Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany; German Cancer Consortium (DKTK), partner site Dresden, and German Cancer Research Center (DKFZ), Heidelberg, Germany.

Purpose: Experimental assessment of inter-centre variation and absolute accuracy of stopping-power-ratio (SPR) prediction within 17 particle therapy centres of the European Particle Therapy Network.

Material And Methods: A head and body phantom with seventeen tissue-equivalent materials were scanned consecutively at the participating centres using their individual clinical CT scan protocol and translated into SPR with their in-house CT-number-to-SPR conversion. Inter-centre variation and absolute accuracy in SPR prediction were quantified for three tissue groups: lung, soft tissues and bones. Read More

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Millimeter-long metamaterial surface-emitting antenna in the silicon photonics platform.

Opt Lett 2021 Aug;46(15):3733-3736

Integrated optical antennas are key components for on-chip light detection and ranging technology (LIDAR). In order to achieve a highly collimated far field with reduced beam divergence, antenna lengths on the order of several millimeters are required. In the high-index contrast silicon photonics platform, achieving such long antennas typically demands weakly modulated gratings with lithographic minimum feature sizes below 10 nm. Read More

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Terahertz emission from ultrathin bismuth layers.

Opt Lett 2021 Aug;46(15):3681-3684

Thinner than 10 nm layers of bismuth (Bi) were grown on (111) Si substrates by molecular beam epitaxy. Terahertz (THz) radiation pulses from these layers excited by tunable wavelength femtosecond optical pulses were measured. THz emission sets on when the photon energy exceeds 0. Read More

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Lens-free digital holographic microscopy for cell imaging and tracking by Fresnel diffraction from a phase discontinuity.

Opt Lett 2021 Aug;46(15):3516-3519

In this Letter, a very simple, stable, and portable lensless digital holographic (DH) microscopy method is presented relying on the Fresnel diffraction (FD) of light from a phase discontinuity (PD). A phase plate in the transmission or a physical step in the reflection can be employed in the path of the divergent beam of a coherent light source as a component imposing the PD. The recorded diffraction pattern in the vicinity of the PD is a hologram produced by off-axis overlapping of two diffracted waves in both sides of the boundary region with adjustable fringe modulation. Read More

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Linear Energy Transfer Incorporated Spot-Scanning Proton Arc Therapy Optimization: A Feasibility Study.

Front Oncol 2021 12;11:698537. Epub 2021 Jul 12.

Department of Radiation Oncology, Beaumont Health System, Royal Oak, MI, United States.

Purpose: To integrate dose-averaged linear energy transfer (LET) into spot-scanning proton arc therapy (SPArc) optimization and to explore its feasibility and potential clinical benefits.

Methods: An open-source proton planning platform (OpenREGGUI) has been modified to incorporate LET into optimization for both SPArc and multi-beam intensity-modulated proton therapy (IMPT) treatment planning. SPArc and multi-beam IMPT plans with different beam configurations for a prostate patient were generated to investigate the feasibility of LET-based optimization using SPArc in terms of spatial LET distribution and plan delivery efficiency. Read More

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The impact of time to prostate specific antigen nadir on biochemical recurrence and mortality rates after radiation therapy for localized prostate cancer.

Urol Oncol 2021 Jul 26. Epub 2021 Jul 26.

Cancer Prognostics and Health Outcomes Unit, Division of Urology, University of Montréal Health Center, Montréal, Québec, Canada; Martini-Klinik Prostate Cancer Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany. Electronic address:

Purpose: To investigate the effect of time to prostate-specific antigen (PSA) nadir (TTN) after radiation therapy (RTx) for prostate cancer (PCa) on biochemical recurrence (BCR) and overall survival (OS) rates.

Patients And Methods: We analyzed 2,506 patients treated with RTx (external beam radiotherapy, brachytherapy or combinations) between years 2000 and 2021. Kaplan Meier and multivariable Cox regression models tested BCR-free survival and OS after stratification according to TTN (≤24 vs. Read More

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Reconstruction of the Anterior External Auditory Canal With Mastoid Cortex Autologous Bone Graft.

Otol Neurotol 2021 Jul 28. Epub 2021 Jul 28.

Georgetown University School of Medicine Department of Otolaryngology and Head and Neck Surgery, Medstar Georgetown University Hospital, Washington DC.

Objective: To describe the surgical management of temporomandibular joint (TMJ) herniation with external auditory canal (EAC) reconstruction using autologous bone grafting from the mastoid cortex.

Study Design: Retrospective case series.

Setting: A tertiary university medical center. Read More

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Radiographic features in 2D imaging as predictors for justified CBCT examinations of canine-induced root resorption.

Dentomaxillofac Radiol 2021 Jul 29:20210165. Epub 2021 Jul 29.

Department of Clinical Dentistry, Section for Oral and Maxillofacial Radiology, University of Bergen, Norway, United Kingdom.

Objectives: This retrospective observational study aimed to evaluate the diagnostic accuracy of two-dimensional radiographs on canine-induced root resorption (CIRR) in lateral incisors and identify predictors of CIRR in patients with impacted maxillary canines (IMC).

Methods: Ninety-nine patients aged 9-17 years, with 156 IMCs, were included in the study. All had CBCT-volumes and two-dimensional radiographs consisting of at least one panoramic radiograph. Read More

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The Impact of Radiotherapy Delay in Breast Conservation Patients Not Receiving Chemotherapy and the Rationale for Dichotomizing the Radiation Oncology Time-Dependent Standard into Two Quality Measures.

Ann Surg Oncol 2021 Jul 29. Epub 2021 Jul 29.

The Data Working Group of the National Accreditation Program for Breast Centers, Chicago, IL, USA.

Introduction: The Commission on Cancer/National Quality Forum breast radiotherapy quality measure establishes that for women < 70 years, adjuvant radiotherapy after breast conserving surgery (BCS) should be started < 1 year from diagnosis. This was intended to prevent accidental radiotherapy omission or delay due to a long interval between surgery and chemotherapy completion, when radiation is delivered. However, the impact on patients not receiving chemotherapy, who proceed from surgery directly to radiotherapy, remains unknown. Read More

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High-Efficiency Down-Conversion Radiation Fluorescence and Ultrafast Photoluminescence (1.2 ns) at the Interface of Hybrid CsPbBr-CsI Nanocrystals.

J Phys Chem Lett 2021 Jul 29:7342-7349. Epub 2021 Jul 29.

State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials, Sun Yat-sen University, Guangzhou 510275, China.

The research of fast scintillators in positron emission tomography and other applications based on time-of-flight technology promotes the development of radiation detection. However, because of the current lack of efficient and fast carrier radiation recombination pathways, the research on scintillator radioluminescence (RL) still faces severe challenges. Here, we propose an effective interface carrier transport mechanism: CsI:Na crystal and CsPbBr nanocrystals (NCs) interface to form a new phase and a continuous heterostructure, providing an effective channel for X-ray excited carrier transfer to CsPbBr. Read More

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Ankle hemophilic arthropathy: literature review.

Am J Blood Res 2021 15;11(3):206-216. Epub 2021 Jun 15.

Department of Ageing, Neurosciences, Head-Neck and Orthopedics Sciences, Orthopedics and Traumatology, Fondazione Policlinico Universitario Agostino Gemelli IRCSS Rome, Italy.

Hemophilia is a bleeding disorder characterized by the deficiency of a coagulation factors. The hemarthrosis is the most common and earliest manifestation. Repeated hemarthrosis over time causes the development of hemophilic arthropathy. Read More

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Towards real-time PGS range monitoring in proton therapy of prostate cancer.

Sci Rep 2021 Jul 28;11(1):15331. Epub 2021 Jul 28.

German Cancer Research Center - DKFZ, Heidelberg, Germany.

Proton therapy of prostate cancer (PCPT) was linked with increased levels of gastrointestinal toxicity in its early use compared to intensity-modulated radiation therapy (IMRT). The higher radiation dose to the rectum by proton beams is mainly due to anatomical variations. Here, we demonstrate an approach to monitor rectal radiation exposure in PCPT based on prompt gamma spectroscopy (PGS). Read More

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Implementation and experimental evaluation of Mega-voltage fan-beam CT using a linear accelerator.

Radiat Oncol 2021 Jul 28;16(1):139. Epub 2021 Jul 28.

Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.

Background: Mega-voltage fan-beam Computed Tomography (MV-FBCT) holds potential in accurate determination of relative electron density (RED) and proton stopping power ratio (SPR) but is not widely available.

Objective: To demonstrate the feasibility of MV-FBCT using a medical linear accelerator (LINAC) with a 2.5 MV imaging beam, an electronic portal imaging device (EPID) and multileaf collimators (MLCs). Read More

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Can patients with low-risk prostate cancer really benefit from radical treatment?: A systematic review and network meta-analysis.

Andrologia 2021 Jul 28:e14122. Epub 2021 Jul 28.

Department of Urology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Dongcheng District, Beijing, China.

Radical prostatectomy, radiotherapy and active surveillance are three widely used treatment options for patients with low-risk prostate cancer, but the relative effects are controversial. We searched PubMed, Embase and Web of Science until June 2020, focusing on the studies comparing the effect of radical prostatectomy, radiotherapy and active surveillance in patients with low-risk prostate cancer. Through the random-effects model, dichotomous data were extracted and summarised by odds ratio with a 95% confidence interval. Read More

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Geometric accuracy of magnetic resonance imaging-derived virtual 3-dimensional bone surface models of the mandible in comparison to computed tomography and cone beam computed tomography: A porcine cadaver study.

Clin Implant Dent Relat Res 2021 Jul 27. Epub 2021 Jul 27.

Department of Diagnostic and Interventional Neuroradiology, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany.

Background: Providing accurate 3-dimensional virtual bone surface models is a prerequisite for virtual surgical planning and additive manufacturing in craniomaxillofacial surgery. For this purpose, magnetic resonance imaging (MRI) may be a radiation-free alternative to computed tomography (CT) and cone beam computed tomography (CBCT).

Purpose: The aim of this study was to assess the geometric accuracy of 3-dimensional T1-weighted MRI-derived virtual bone surface models of the mandible in comparison to CT and CBCT. Read More

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FLASH radiotherapy with carbon ion beams.

Med Phys 2021 Jul 28. Epub 2021 Jul 28.

GSI Helhmoltzzentrum für Schwerionenforschung, Biophysics Department, Darmstadt, Germany.

FLASH radiotherapy is considered a new potential breakthrough in cancer treatment. Ultra-high dose rates (>40 Gy/s) have been shown to reduce toxicity in the normal tissue without compromising tumor control, resulting in a widened therapeutic window. These high dose rates are more easily achievable in the clinic with charged particles, and clinical trials are indeed ongoing using electrons or protons. Read More

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Development of a storage phosphor imaging system for proton pencil beam spot profile determination.

Med Phys 2021 Jul 28. Epub 2021 Jul 28.

Department of Radiation Oncology, University of Kansas, School of Medicine, Kansas City, KS, 66160, USA.

Purpose: Accurate 2D profile measurements at submillimeter precision are necessary for proton beam commissioning and periodic quality assurance (QA) purposes and are currently performed at our institution with a commercial scintillation detector (Lynx PT) with limited means for independent checks. The purpose of this work is to create an independent dosimetry system consisting of an in-house optical scanner and a BaFBrI:Eu storage phosphor dosimeter by: (a) determining the optimal settings for the optical scanner, (b) measuring 2D proton spot profiles with the storage phosphors and (c) comparing them to similar measurements using a commercial scintillation detector.

Methods: An in-house two-dimensional (2D) laboratory optical scanner was constructed and spatially calibrated for accurate 2D photostimulated luminescence (PSL) dosimetry. Read More

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Prompt-gamma emission in GEANT4 revisited and confronted with experiment.

Phys Med 2021 Jul 26;88:250-261. Epub 2021 Jul 26.

Institute of Nuclear Physics Polish Academy of Sciences, Kraków, Poland.

Purpose: The field of online monitoring of the beam range is one of the most researched topics in proton therapy over the last decade. The development of detectors that can be used for beam range verification under clinical conditions is a challenging task. One promising possible solution are modalities that record prompt-gamma radiation produced by the interactions of the proton beam with the target tissue. Read More

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In vivo imaging of the microglial landscape after whole brain radiation therapy.

Int J Radiat Oncol Biol Phys 2021 Jul 24. Epub 2021 Jul 24.

Department of Radiation Oncology, University of Rochester, Rochester, NY. Electronic address:

Purpose: Whole brain radiation therapy (WBRT) is an important treatment for patients with multiple brain metastases, but can also cause cognitive deterioration. Microglia, the resident immune cells of the brain, promote a pro-inflammatory environment and likely contribute to cognitive decline after WBRT. To investigate the temporal dynamics of the microglial reaction in individual mice to WBRT, we developed a novel in vivo experimental model using cranial window implants and longitudinal imaging. Read More

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Interstitial Brachytherapy for Orbital Sebaceous Carcinoma.

Ophthalmic Plast Reconstr Surg 2021 Jul 27. Epub 2021 Jul 27.

The Department of Ocular Tumor, Orbital Disease and Ophthalmic Radiation Therapy, The New York Eye Cancer Center, New York, New York, U.S.A. The Departments of Radiation Oncology and Ophthalmology, The New York Eye and Ear Infirmary of Mount Sinai, New York, New York, U.S.A.

Sebaceous carcinoma is characterized by its aggressive local tumor behavior and ability to metastasize. Small periocular sebaceous carcinoma are typically treated by excision with cryotherapy. Larger tumors often require adjuvant external beam radiotherapy (EBRT) and/or exenteration surgery. Read More

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Target coverage and cardiopulmonary sparing with the updated ESTRO-ACROP contouring guidelines for postmastectomy radiation therapy after breast reconstruction: a treatment planning study using VMAT and proton PBS techniques.

Acta Oncol 2021 Jul 27:1-12. Epub 2021 Jul 27.

Harvard Radiation Oncology Program, Boston, MA, USA.

Background: The European Society for Therapeutic Radiology and Oncology Advisory Committee in Radiation Oncology Practice (ESTRO-ACROP) recently released new contouring guidelines for postmastectomy radiation therapy (PMRT) after implant-based reconstruction (IBR). As compared to prior ESTRO guidelines, the new guidelines primarily redefined the chest wall (CW) target to exclude the breast prosthesis. In this study, we assessed the impact of these changes on treatment planning and dosimetric outcomes using volumetric-modulated arc therapy (VMAT) and proton pencil-beam scanning (PBS) therapy. Read More

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The root cause analysis on failed patient-specific measurements of pencil beam scanning protons using a 2D detection array with finite size ionization chambers.

J Appl Clin Med Phys 2021 Jul 26. Epub 2021 Jul 26.

Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, FL, USA.

The aim of this report is to present the root cause analysis on failed patient-specific quality assurance (QA) measurements of pencil beam scanning (PBS) protons; referred to as PBS-QA measurement. A criterion to fail a PBS-QA measurement is having a <95% passing rate in a 3.0%-3. Read More

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Pituitary adenoma treatment plan quality comparison between linear accelerator volumetric modulated arc therapy and Leksell Gamma Knife® radiosurgery.

Med Dosim 2021 Jul 23. Epub 2021 Jul 23.

Motol University Hospital, Oncology Clinic, Prague 5, Czech Republic; Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Department of Dosimetry and Application of Ionizing Radiation, Prague 110 00, Czech Republic.

The aim of this study was to compare radiosurgical treatment plan quality of a linear accelerator with Leksell Gamma Knife (LGK) for pituitary adenoma irradiation. Thirty pituitary adenoma patients were evaluated in this study. Treatment plans were prepared on LGK and stereotactic linear accelerator Varian TrueBeam STx. Read More

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High Dose Rate Brachytherapy for Inoperable Endometrial Cancer: a Case Series and Systematic Review of the Literature.

Clin Oncol (R Coll Radiol) 2021 Jul 23. Epub 2021 Jul 23.

Department of Radiation Oncology, Montefiore Medical Center, Bronx, New York, USA.

Endometrial cancer is a common gynaecological cancer, is typically early stage and treated with surgery. For patients where surgery is difficult or dangerous, definitive radiation therapy is the next best option. This study included a single institution case series (step 1) and a systematic review of the literature (step 2). Read More

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Reduction of GTV to high-risk CTV radiation margin in head and neck squamous cell carcinoma significantly reduced acute and late radiation-related toxicity with comparable outcomes.

Radiother Oncol 2021 Jul 23. Epub 2021 Jul 23.

Department of Radiation Oncology, Netherlands Cancer Institute, Amsterdam, The Netherlands.

Background And Purpose: We aim to retrospectively investigate whether reducing GTV to high-risk CTV margin will significantly reduce acute and late toxicity without jeopardizing outcome in head-and-neck squamous cell carcinoma (HNSCC) treated with definitive (chemo)radiation.

Materials And Methods: Between April 2015 and April 2019, 155 consecutive patients were treated with GTV to high-risk CTV margin of 10mm and subsequently another 155 patients with 6mm margin. The CTV-PTV margin was 3mm for both groups. Read More

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Improving efficiency in the radiation management of multiple brain metastases using a knowledge-based planning solution for single-isocentre volumetric modulated arc therapy (VMAT) technique.

J Med Radiat Sci 2021 Jul 26. Epub 2021 Jul 26.

Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales, Australia.

Introduction: This study aimed to develop a single-isocentre volumetric modulated arc therapy (si-VMAT) technique for multiple brain metastases using knowledge-based planning software, comparing it with a multiple-isocentre stereotactic radiosurgery (mi-SRS) planning approach.

Methods: Twenty-six si-VMAT plans were created and uploaded into RapidPlan (RP) to create a si-VMAT model. Ten patients, with 2 to 6 metastases (mets), were planned with a si-VMAT technique utilising RP, and a mi-SRS technique on Brainlab iPlan. Read More

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Short Androgen Suppression and Radiation Dose Escalation in Prostate Cancer: 12-Year Results of EORTC Trial 22991 in Patients With Localized Intermediate-Risk Disease.

J Clin Oncol 2021 Jul 26:JCO2100855. Epub 2021 Jul 26.

European Organization for Research and Treatment of Cancer, Brussels, Belgium.

Purpose: The European Organisation for Research and Treatment of Cancer (EORTC) trial 22991 (NCT00021450) showed that 6 months of concomitant and adjuvant androgen suppression (AS) improves event- (EFS, Phoenix) and clinical disease-free survival (DFS) of intermediate- and high-risk localized prostatic carcinoma, treated by external-beam radiotherapy (EBRT) at 70-78 Gy. We report the long-term results in intermediate-risk patients treated with 74 or 78 Gy EBRT, as per current guidelines.

Patient And Methods: Of 819 patients randomly assigned between EBRT or EBRT plus AS started on day 1 of EBRT, 481 entered with intermediate risk (International Union Against Cancer TNM 1997 cT1b-c or T2a with prostate-specific antigen (PSA) ≥ 10 ng/mL or Gleason ≤ 7 and PSA ≤ 20 ng/mL, N0M0) and had EBRT planned at 74 (342 patients, 71. Read More

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Characterization of automatic treatment planning approaches in radiotherapy.

Phys Imaging Radiat Oncol 2021 Jul 13;19:60-65. Epub 2021 Jul 13.

Department of Radiation Oncology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.

Background And Purpose: Automatic approaches are widely implemented to automate dose optimization in radiotherapy treatment planning. This study systematically investigates how to configure automatic planning in order to create the best possible plans.

Materials And Methods: Automatic plans were generated using protocol based automatic iterative optimization. Read More

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