352 results match your criteria margin gtv


Optimization of treatment isocenter location in single-isocenter linac-based stereotactic radiosurgery for management of multiple brain metastases.

Med Phys 2021 Oct 16. Epub 2021 Oct 16.

Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ.

Purpose: Single-isocenter linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) has become a promising treatment technique for the management of multiple brain metastases. Because of the high prescription dose and steep dose gradient, SRS plans are sensitive to geometric errors, resulting in loss of target coverage and suboptimal local tumor control. Current planning techniques rely on adding a uniform and isotropic setup margin to all gross tumor volumes (GTVs) to account for rotational uncertainties. Read More

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October 2021

Dosimetric evaluation of different planning techniques based on flattening filter-free beams for central and peripheral lung stereotactic body radiotherapy.

Biomed Phys Eng Express 2021 Oct 12. Epub 2021 Oct 12.

Department of Radiotherapy, Government Medical College Patiala, Sangrur Road, Patiala, Punjab, 147001, INDIA.

This study aimed to dosimetrically compare and evaluate the flattening filter-free (FFF) photon beam-based three-dimensional conformal radiotherapy (3DCRT), intensity-modulated radiation therapy (IMRT), and volumetric modulated arc therapy (VMAT) for lungstereotactic body radiotherapy (SBRT). RANDO phantom computed tomography (CT) images were used for treatment planning. Gross tumor volumes (GTVs) were delineated in the central and peripheral lung locations. Read More

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October 2021

Accuracy of electroanatomical mapping-guided cardiac radiotherapy for ventricular tachycardia: pitfalls and solutions.

Europace 2021 Sep 15. Epub 2021 Sep 15.

Willem Einthoven Center for Cardiac Arrhythmia research and Management, Department of Cardiology, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands.

Aims: To analyse and optimize the interobserver agreement for gross target volume (GTV) delineation on cardiac computed tomography (CCT) based on electroanatomical mapping (EAM) data acquired to guide radiotherapy for ventricular tachycardia (VT).

Methods And Results: Electroanatomical mapping data were exported and merged with the segmented CCT using manual registration by two observers. A GTV was created by both observers for predefined left ventricular (LV) areas based on preselected endocardial EAM points indicating a two-dimensional (2D) surface area of interest. Read More

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September 2021

Quantitative Bioluminescence Tomography-guided Conformal Irradiation for Preclinical Radiation Research.

Int J Radiat Oncol Biol Phys 2021 Aug 16. Epub 2021 Aug 16.

Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland; Biomedical Imaging and Radiation Technology Laboratory, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas. Electronic address:

Purpose: Widely used cone beam computed tomography (CBCT)-guided irradiators in preclinical radiation research are limited to localize soft tissue target because of low imaging contrast. Knowledge of target volume is a fundamental need for radiation therapy (RT). Without such information to guide radiation, normal tissue can be overirradiated, introducing experimental uncertainties. Read More

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Postsurgical geometrical variations of tumor bed and brainstem during photon and proton therapy for pediatric tumors of the posterior fossa: dosimetric impact and predictive factors.

Strahlenther Onkol 2021 Aug 5. Epub 2021 Aug 5.

Antoine Lacassagne Centre, Department of Radiation Oncology, Fédération Claude-Lalanne, University of Côte d'Azur, Nice, France.

Purpose: Brainstem radionecrosis is an important issue during the irradiation of tumors of the posterior fossa. The aim of the present study is to analyze postsurgical geometrical variations of tumor bed (TB) and brainstem (BS) and their impact on dosimetry.

Methods: Retrospective collection of data from pediatric patients treated at a single institution. Read More

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Intrafraction stability using full head mask for brain stereotactic radiotherapy.

J Appl Clin Med Phys 2021 Sep 4;22(9):360-370. Epub 2021 Aug 4.

Department of Radiation Oncology, Juntendo University, Tokyo, Japan.

Purpose: We investigated the immobilization accuracy of a new type of thermoplastic mask-the Double Shell Positioning System (DSPS)-in terms of geometry and dose delivery.

Methods: Thirty-one consecutive patients with 1-5 brain metastases treated with stereotactic radiotherapy (SRT) were selected and divided into two groups. Patients were divided into two groups. Read More

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September 2021

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 Sep 24;162:170-177. Epub 2021 Jul 24.

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 10 mm and subsequently another 155 patients with 6 mm margin. The CTV-PTV margin was 3 mm for both groups. Read More

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September 2021

Additional Value of 18F-FDOPA Amino Acid Analog Radiotracer to Irradiation Planning Process of Patients With Glioblastoma Multiforme.

Front Oncol 2021 6;11:699360. Epub 2021 Jul 6.

Doctoral School of Health Sciences, University of Pécs, Pécs, Hungary.

Purpose: To investigate the added value of 6-(18F]-fluoro-L-3,4-dihydroxyphenylalanine (FDOPA) PET to radiotherapy planning in glioblastoma multiforme (GBM).

Methods: From September 2017 to December 2020, 17 patients with GBM received external beam radiotherapy up to 60 Gy with concurrent and adjuvant temozolamide. Target volume delineations followed the European guideline with a 2-cm safety margin clinical target volume (CTV) around the contrast-enhanced lesion+resection cavity on MRI gross tumor volume (GTV). Read More

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Planning target volume margin assessment for online adaptive MR-guided dose-escalation in rectal cancer on a 1.5 T MR-Linac.

Radiother Oncol 2021 Sep 17;162:150-155. Epub 2021 Jul 17.

Department of Radiation Oncology, University Medical Center Utrecht, The Netherlands.

Purpose: This study assessed the margins needed to cover tumor intrafraction motion during an MR-guided radiotherapy (MRgRT) dose-escalation strategy in intermediate risk rectal cancer.

Methods: Fifteen patients with rectal cancer were treated with neoadjuvant short-course radiotherapy, 5x5 Gy, according to an online adaptive workflow on a 1.5 T MR-linac. Read More

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September 2021

Limited recurrence distance of glioblastoma under modern radiotherapy era.

BMC Cancer 2021 Jun 22;21(1):720. Epub 2021 Jun 22.

NHC Key Laboratory of Personalized Diagnosis and Treatment of Nasopharyngeal Carcinoma (Jiangxi Cancer Hospital of Nanchang University), 519 East Beijing Road, Nanchang, 330029, China.

Background: The optimal treatment volume for Glioblastoma multiforme (GBM) is still a subject of debate worldwide. The current study was aimed to determine the distances between recurring tumors and the edge of primary lesions, and thereby provide evidence for accurate target area delineation.

Methods: Between October 2007 and March 2019, 68 recurrent patients with GBM were included in our study. Read More

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Use of genetic algorithm for PTV optimization in single isocenter multiple metastases radiosurgery treatments with Brainlab Elements™.

Phys Med 2021 Jun 29;86:82-90. Epub 2021 May 29.

Instituto Zunino, Obispo Oro 423, 5000 Córdoba, Argentina. Electronic address:

Purpose: To optimize PTV margins for single isocenter multiple metastases stereotactic radiosurgery through a genetic algorithm (GA) that determines the maximum effective displacement of each target (GTV) due to rotations.

Method: 10 plans were optimized. The plans were created with Elements Multiple Mets™ (Brainlab AG, Munchen, Germany) from a predefined template. Read More

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Joint Optimization of Photon-Carbon Ion Treatments for Glioblastoma.

Int J Radiat Oncol Biol Phys 2021 10 28;111(2):559-572. Epub 2021 May 28.

Department of Medical Physics in Radiation Oncology, German Cancer Research Center, Heidelberg, Germany.

Purpose: Carbon ions are radiobiologically more effective than photons and are beneficial for treating radioresistant gross tumor volumes (GTV). However, owing to a reduced fractionation effect, they may be disadvantageous for treating infiltrative tumors, in which healthy tissue inside the clinical target volume (CTV) must be protected through fractionation. This work addresses the question: What is the ideal combined photon-carbon ion fluence distribution for treating infiltrative tumors given a specific fraction allocation between photons and carbon ions?

Methods And Materials: We present a method to simultaneously optimize sequentially delivered intensity modulated photon (IMRT) and carbon ion (CIRT) treatments based on cumulative biological effect, incorporating both the variable relative biological effect of carbon ions and the fractionation effect within the linear quadratic model. Read More

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October 2021

CyberKnife radiation therapy as a platform for translational mouse studies.

Int J Radiat Biol 2021 23;97(9):1261-1269. Epub 2021 Jun 23.

Department of Radiation Oncology and CyberKnife Center, Faculty of Medicine, University Hospital Cologne, University of Cologne, Cologne, Germany.

Purpose: Radiation therapy (RT) is a common nonsurgical treatment in the management of patients with cancer. While genetically engineered mouse models (GEMM) recapitulate human disease, conventional linear particle accelerator systems are not suited for state-of-the-art, imageguided targeted RT (IGRT) of these murine tumors. We employed the CyberKnife (CK; Accuray) platform for IGRT of GEMM-derived non-small cell lung cancer (NSCLC) lesions. Read More

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September 2021

A clinicopathologic analysis of microscopic extension in small cell lung cancer and lung adenocarcinoma: Determination of clinical target volume with precise radiotherapy.

Thorac Cancer 2021 07 24;12(13):1973-1982. Epub 2021 May 24.

Department of Radiation Oncology, Peking University First Hospital, Beijing, China.

Purpose: The identification of the clinical target volume (CTV) is particularly important in the precise radiotherapy of lung cancer. The purpose of this study was to determine the extension margin from gross tumor volume (GTV) to CTV in primary small cell lung cancer (SCLC) and lung adenocarcinoma (ADC) by microscopic extension (ME).

Material And Methods: The data of 25 cases of SCLC and 29 cases of ADC from August 2015 to August 2020 were analyzed. Read More

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Dosimetric feasibility on hypofractionated intensity-modulated radiotherapy and simultaneous integrated boost for locally advanced unresectable pancreatic cancer with helical tomotherapy.

J Gastrointest Oncol 2021 Apr;12(2):496-506

Department of Radiotherapy, Air Force Medical Center of PLA, Beijing, China.

Background: This dosimetric study on locally advanced pancreatic cancer (LAPC) and the surrounding gastrointestinal organs at risk (OARs) aimed at exploring the potential of further improving the internal dose and reducing the fractionation number by concurrent hypofractionated simultaneous integrated boost (SIB) radiotherapy using helical tomotherapy (HT).

Methods: We collected computed tomography positioning images from a LAPC study of 17 consecutive patients. Gross tumor volume (GTV)1, GTV2, and GTV3 were defined as the GTV minus a margin of 3, 6, and 9 mm from the external part in all directions, respectively. Read More

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Impact of PTV margin reduction (2 mm to 0 mm) on pseudoprogression in stereotactic radiotherapy of solitary brain metastases.

Tech Innov Patient Support Radiat Oncol 2021 Mar 3;17:40-47. Epub 2021 Mar 3.

Department of Radiation Oncology, Haaglanden Medical Center, The Hague, the Netherlands.

Purpose: To determine the influence of PTV-margin (0 mm versus 2 mm) on the incidence of pseudoprogression (PP) and local tumour control (LC) in patients treated with stereotactic radiotherapy (SRT) for solitary brain metastases.

Methods: Patients were treated on Novalis LINAC. Three dose schedules were used depending on the PTV-size. Read More

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Can reducing planning safety margins broaden the inclusion criteria for lung stereotactic ablative body radiotherapy?

J Med Radiat Sci 2021 Sep 2;68(3):298-309. Epub 2021 May 2.

South Western Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.

Introduction: Stereotactic ablative body radiotherapy (SABR) is currently indicated for inoperable, early-stage non-small cell lung carcinoma (NSCLC). Advancements in image-guidance technology continue to improve treatment precision and enable reductions in planning safety margins. We investigated the dosimetric benefits of margin reduction, its potential to extend SABR to more NSCLC patients and the factors influencing plan acceptability. Read More

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September 2021

Reduction of margin to compensate the respiratory tumor motion by the analysis of dosimetric internal target volume in lung SBRT with nonuniform volume prescription method.

Med Phys 2021 Jun 24;48(6):3200-3207. Epub 2021 Apr 24.

Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Hiroshima, 734-8551, Japan.

Purpose: To develop a dosimetric internal target volume (ITV) margin (DIM) for respiratory motion in lung stereotactic body radiotherapy (SBRT) and to evaluate DIM with a nonuniform volume prescription (NVP) and the point prescription (PP).

Methods: Volumetric modulated arc therapy (VMAT) treatment plans with PP and NVP were created on a heterogeneous programmable respiratory motion phantom, with a tumor (30-mm diameter) inside a cylindrical lung insert. The tumor was defined as the gross tumor volume (GTV), equal to the clinical target volume (CTV). Read More

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Geometric Reproducibility of Fiducial Markers and Efficacy of a Patient-Specific Margin Design Using Deep Inspiration Breath Hold for Stereotactic Body Radiation Therapy for Pancreatic Cancer.

Adv Radiat Oncol 2021 Mar-Apr;6(2):100655. Epub 2021 Jan 22.

Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University of School of Medicine, Baltimore, Maryland.

Purpose: In patients undergoing stereotactic body radiation therapy (SBRT) for pancreatic adenocarcinoma, the reproducibility of tumor positioning between deep-inspiration breath holds is unclear. We characterized this variation with fiducials at simulation and treatment and investigated whether a patient-specific breath-hold (PSBH) margin would help account for intrafraction variation at treatment.

Methods And Materials: We analyzed 20 consecutive patients with pancreatic cancer who underwent SBRT with deep-inspiration breath holds. Read More

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January 2021

The Definition and Delineation of the Target Area of Radiotherapy Based on the Recurrence Pattern of Glioblastoma After Temozolomide Chemoradiotherapy.

Front Oncol 2020 22;10:615368. Epub 2021 Feb 22.

Department of Radiation Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.

Radiotherapy is an important treatment for glioblastoma (GBM), but there is no consensus on the target delineation for GBM radiotherapy. The Radiation Therapy Oncology Group (RTOG) and European Organisation for Research and Treatment of Cancer (EORTC) each have their own rules. Our center adopted a target volume delineation plan based on our previous studies. Read More

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February 2021

An Inter-observer Study to Determine Radiotherapy Planning Target Volumes for Recurrent Gynaecological Cancer Comparing Magnetic Resonance Imaging Only With Computed Tomography-Magnetic Resonance Imaging.

Clin Oncol (R Coll Radiol) 2021 05 25;33(5):307-313. Epub 2021 Feb 25.

Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, Sutton, London, UK.

Aims: Target delineation uncertainty is arguably the largest source of geometric uncertainty in radiotherapy. Several factors can affect it, including the imaging modality used for delineation. It is accounted for by applying safety margins to the target to produce a planning target volume (PTV), to which treatments are designed. Read More

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Evaluation of interim MRI changes during limited-field radiation therapy for glioblastoma and implications for treatment planning.

Radiother Oncol 2021 05 13;158:237-243. Epub 2021 Feb 13.

Department of Radiation Oncology, Washington University School of Medicine, St. Louis, United States. Electronic address:

Background And Purpose: Consensus for defining gross tumor volume (GTV) and clinical target volume (CTV) for limited-field radiation therapy (LFRT) of GBM are not well established. We leveraged a department MRI simulator to image patients before and during LFRT to address these questions.

Materials And Methods: Supratentorial GBM patients receiving LFRT (46 Gy + boost to 60 Gy) underwent baseline MRI (MRI1) and interim MRI during RT (MRI2). Read More

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New target volume delineation and PTV strategies to further personalise radiotherapy.

Phys Med Biol 2021 02 25;66(5):055024. Epub 2021 Feb 25.

Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, Fulham Road, London, SW3 6JJ, United Kingdom.

Target volume delineation uncertainty (DU) is arguably one of the largest geometric uncertainties in radiotherapy that are accounted for using planning target volume (PTV) margins. Geometrical uncertainties are typically derived from a limited sample of patients. Consequently, the resultant margins are not tailored to individual patients. Read More

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February 2021

Delivery of magnetic resonance-guided single-fraction stereotactic lung radiotherapy.

Phys Imaging Radiat Oncol 2020 Apr 20;14:17-23. Epub 2020 May 20.

Department of Radiation Oncology, Amsterdam University Medical Centers, Location VUmc, de Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.

Background And Purpose: Single-fraction stereotactic ablative radiotherapy (SABR) is an effective treatment for early-stage lung cancer, but concerns remain about the accurate delivery of SABR in a single session. We evaluated the delivery of single-fraction lung SABR using magnetic resonance (MR)-guidance.

Materials And Methods: An MR-simulation was performed in 17 patients, seven of whom were found to be unsuitable, largely due to unreliable tracking of small tumors. Read More

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Does an immobilization mask have added value during planning magnetic resonance imaging for stereotactic radiotherapy of brain tumours?

Phys Imaging Radiat Oncol 2020 Jan 6;13:7-13. Epub 2020 Mar 6.

UMC Utrecht, Department of Radiation Oncology, Utrecht, The Netherlands.

Background And Purpose: When using an immobilization mask, a magnetic resonance imaging (MRI) head receive coil cannot be used and patients may experience discomfort during the examination. We therefore wish to assess the added value of an immobilization mask during all MRI scans intended for cranial stereotactic radiotherapy (SRT) planning.

Materials And Methods: An MRI was acquired with and without a thermoplastic immobilization mask in ten patients eligible for SRT. Read More

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January 2020

Focal low-dose-rate prostate brachytherapy for low- and intermediate-risk prostate cancer.

J Contemp Brachytherapy 2020 Dec 16;12(6):554-561. Epub 2020 Dec 16.

Department of Radiation Oncology, Juntendo University, Tokyo, Japan.

Purpose: To prospectively investigate the efficacy and feasibility of focal low-dose-rate (LDR) prostate brachytherapy for low- and intermediate-risk prostate cancer.

Material And Methods: Between October 2014 and May 2019, nineteen low- and intermediate-risk prostate cancer patients who presented with abnormality on both diffusion-weighted and T2-weighted magnetic resonance imaging (MRI) underwent focal LDR brachytherapy at our institution. Focal gross tumor volume (F-GTV) was delineated on transrectal ultrasound, based on abnormality seen on fused T2-weighted MRI. Read More

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December 2020

Maximum distance in single-isocenter technique of stereotactic radiosurgery with rotational error using margin-based analysis.

Radiol Phys Technol 2021 Mar 3;14(1):57-63. Epub 2021 Jan 3.

Department of Radiology and Radiation Oncology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Japan.

Through geometrical simulation, we evaluated the effect of rotational error in patient setup on geometrical coverage and calculated the maximum distance between the isocenter and target, where the clinical PTV margin secures geometrical coverage with a single-isocenter technique. We used simulated spherical GTVs with diameters of 1.0 (GTV 1), 1. Read More

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DeepTarget: Gross tumor and clinical target volume segmentation in esophageal cancer radiotherapy.

Med Image Anal 2021 02 19;68:101909. Epub 2020 Nov 19.

PAII Inc., Bethesda, MD, USA.

Gross tumor volume (GTV) and clinical target volume (CTV) delineation are two critical steps in the cancer radiotherapy planning. GTV defines the primary treatment area of the gross tumor, while CTV outlines the sub-clinical malignant disease. Automatic GTV and CTV segmentation are both challenging for distinct reasons: GTV segmentation relies on the radiotherapy computed tomography (RTCT) image appearance, which suffers from poor contrast with the surrounding tissues, while CTV delineation relies on a mixture of predefined and judgement-based margins. Read More

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February 2021

Three-dimensional MRI-based treatment planning approach for non-invasive ocular proton therapy.

Med Phys 2021 Mar 17;48(3):1315-1326. Epub 2021 Jan 17.

Department of Radiation Oncology, Erasmus Medical Center, Rotterdam, The Netherlands.

Purpose: To develop a high-resolution three-dimensional (3D) magnetic resonance imaging (MRI)-based treatment planning approach for uveal melanomas (UM) in proton therapy.

Materials/methods: For eight patients with UM, a segmentation of the gross tumor volume (GTV) and organs-at-risk (OARs) was performed on T1- and T2-weighted 7 Tesla MRI image data to reconstruct the patient MR-eye. An extended contour was defined with a 2. Read More

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1.5 T MR-linac planning study to compare two different strategies of rectal boost irradiation.

Clin Transl Radiat Oncol 2021 Jan 3;26:86-91. Epub 2020 Dec 3.

Department of Radiation Oncology, University Hospital and Medical Faculty, Eberhard Karls University, Tübingen, Germany.

Purpose: To compare treatment plans of two different rectal boost strategies: up-front versus adaptive boost at the 1.5 T MR-Linac.

Methods: Patients with locally advanced rectal cancer (LARC) underwent standard neoadjuvant radiochemotherapy with 50. Read More

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January 2021