2,109 results match your criteria setup errors

Fiducial marker motion relative to the tumor bed has a significant impact on PTV margins in partial breast irradiation.

Radiother Oncol 2021 Jul 27. Epub 2021 Jul 27.

Erasmus MC Cancer Institute, Department of Radiation Oncology, PO Box 2040, 3000 CA Rotterdam, The Netherlands.

Introduction: With the introduction of accelerated partial breast irradiation (APBI) and the trend of reducing the number of fractions, the geometric accuracy of treatment delivery becomes critical. APBI patient setup is often based on fiducials, as the seroma is frequently not visible on pretreatment imaging. We assessed the motion of fiducials relative to the tumor bed between planning CT and treatment, and calculated margins to compensate for this motion. Read More

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Automatic triangulated mesh generation of pulmonary airways from segmented lung 3DCTs for computational fluid dynamics.

Int J Comput Assist Radiol Surg 2021 Jul 30. Epub 2021 Jul 30.

University of California, Los Angeles, CA, 90095, USA.

Purpose: Computational fluid dynamics (CFD) of lung airflow during normal and pathophysiological breathing provides insight into regional pulmonary ventilation. By integrating CFD methods with 4D lung imaging workflows, regions of normal pulmonary function can be spared during treatment planning. To facilitate the use of CFD simulations in a clinical setup, a robust, automated, and CFD-compliant airway mesh generation technique is necessary. Read More

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Psychosomatic symptoms affect radiotherapy setup errors in early breast cancer patients.

Chin J Cancer Res 2021 Jun;33(3):323-330

Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Psycho-oncology, Peking University Cancer Hospital & Institute, Beijing 100142, China.

Objective: To examine the trajectory of psychosomatic symptoms and to explore the impact of psychosomatic symptoms on setup error in patients undergoing breast cancer radiotherapy.

Methods: A total of 102 patients with early breast cancer who received initial radiotherapy were consecutively recruited. The M. Read More

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Dosimetric effects of quality assurance-related setup errors in passive proton therapy for prostate cancer with and without a hydrogel spacer.

Radiol Phys Technol 2021 Jul 27. Epub 2021 Jul 27.

Faculty of Radiological Technology, School of Health Sciences, Fujita Health University, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi, 470-1192, Japan.

The purpose of this study was to evaluate the effect of quality assurance (QA)-related setup errors in passive proton therapy for prostate cancer with and without a hydrogel spacer. We used 20 typical computed tomography (CT) images of prostate cancer: 10 patients with and 10 patients without spacers. The following 12 model errors were assumed: output error ± 2%, range error ± 1 mm, setup error ± 1 mm for three directions, and multileaf collimator (MLC) position error ± 1 mm. Read More

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Inferring Trust From Users' Behaviours; Agents' Predictability Positively Affects Trust, Task Performance and Cognitive Load in Human-Agent Real-Time Collaboration.

Front Robot AI 2021 8;8:642201. Epub 2021 Jul 8.

Department of Computer and Information Sciences, University of Strathclyde, Glasgow, United Kingdom.

Collaborative virtual agents help human operators to perform tasks in real-time. For this collaboration to be effective, human operators must appropriately trust the agent(s) they are interacting with. Multiple factors influence trust, such as the context of interaction, prior experiences with automated systems and the quality of the help offered by agents in terms of its transparency and performance. Read More

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Acute Application of Imidacloprid Alters the Sensitivity of Direction Selective Motion Detecting Neurons in an Insect Pollinator.

Front Physiol 2021 8;12:682489. Epub 2021 Jul 8.

Department of Biology, Lund University, Lund, Sweden.

Cholinergic pesticides, such as the neonicotinoid imidacloprid, are the most important insecticides used for plant protection worldwide. In recent decades, concerns have been raised about side effects on non-target insect species, including altered foraging behavior and navigation. Although pollinators rely on visual cues to forage and navigate their environment, the effects of neonicotinoids on visual processing have been largely overlooked. Read More

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Smartphone Location Recognition with Unknown Modes in Deep Feature Space.

Sensors (Basel) 2021 Jul 14;21(14). Epub 2021 Jul 14.

Department of Marine Technologies, University of Haifa, 199 Aba Khoushy Ave., Haifa 3498838, Israel.

Smartphone location recognition aims to identify the location of a smartphone on a user in specific actions such as talking or texting. This task is critical for accurate indoor navigation using pedestrian dead reckoning. Usually, for that task, a supervised network is trained on a set of defined user modes (smartphone locations), available during the training process. Read More

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Assessment of a Diaphragm Override Strategy for Robustly Optimized Proton Therapy Planning for Esophageal Cancer Patients.

Med Phys 2021 Jul 20. Epub 2021 Jul 20.

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

Purpose: To ensure target coverage in the treatment of esophageal cancer, a density override to the region of diaphragm motion can be applied in the optimization process. Here, we evaluate the benefit of this approach during robust optimization for intensity modulated proton therapy (IMPT) planning.

Materials And Methods: For ten esophageal cancer patients, two robustly optimized IMPT plans were created either using (WDO) or not using (NDO) a diaphragm density override of 1. Read More

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Waveform Estimation from Approximate Quantum Nondemolition Measurements.

Phys Rev Lett 2021 Jul;127(1):010502

Institute for Theoretical Physics, ETH Zurich, 8093 Zurich, Switzerland.

With the advent of gravitational wave detectors employing squeezed light, quantum waveform estimation-estimating a time-dependent signal by means of a quantum-mechanical probe-is of increasing importance. As is well known, backaction of quantum measurement limits the precision with which the waveform can be estimated, though these limits can, in principle, be overcome by "quantum nondemolition" (QND) measurement setups found in the literature. Strictly speaking, however, their implementation would require infinite energy, as their mathematical description involves Hamiltonians unbounded from below. Read More

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Analysis of experimental errors in Mueller matrix channeled polarimeters.

Appl Opt 2021 Jun;60(18):5456-5464

This work analyzes the effect of experimental errors and measurement noise on Mueller matrix channeled spectropolarimeters. The main advantage of this type of polarimeter is the independence on temporal resolution, as it can be used as a snapshot polarimeter. The simulation of the polarimeters with experimental errors and two published extraction methods of the sample Mueller matrix are also presented. Read More

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Proton range uncertainty reduction benefits for skull base tumors in terms of normal tissue complication probability (NTCP) and healthy tissue doses.

Med Phys 2021 Jul 14. Epub 2021 Jul 14.

Division of Radiation Biophysics, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.

Purpose: Proton therapy allows for more conformal dose distributions and lower organ at risk and healthy tissue doses than conventional photon-based radiotherapy, but uncertainties in the proton range currently prevent proton therapy from making full use of these advantages. Numerous developments therefore aim to reduce such range uncertainties. In this work, we quantify the benefits of reductions in range uncertainty for treatments of skull base tumors. Read More

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Investigation of pixel scale calibration on the Elekta iView electronic portal imager.

J Appl Clin Med Phys 2021 Jul 11. Epub 2021 Jul 11.

Genesis Care, Perth, Australia.

This study investigated the variation in electronic portal imager pixel scale at the isocenter plane for Elekta Agility linear accelerators. An in-house MATLAB script was written to process and calculate the pixel scale based on a metal calibration plate supplied by Elekta. Eight pixel plates were compared and found to have manufacturing tolerances within 0. Read More

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The feasibility of an approximate irregular field dose distribution simulation program applied to a respiratory motion compensation system.

Phys Med 2021 Jul 5;88:117-126. Epub 2021 Jul 5.

Department of Mechanical Engineering, National Taipei University of Technology, Taipei, Taiwan. Electronic address:

Purpose: This study optimized our previously proposed simulation program for the approximate irregular field dose distribution (SPAD) and applied it to a respiratory motion compensation system (RMCS) and respiratory motion simulation system (RMSS). The main purpose was to rapidly analyze the two-dimensional dose distribution and evaluate the compensation effect of the RMCS during radiotherapy.

Methods: This study modified the SPAD to improve the rapid analysis of the dose distribution. Read More

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Development and Longitudinal Analysis of Plan-Based Streamlined Quality Assurance on Multiple Positioning Guidance Systems With Single Phantom Setup.

Front Oncol 2021 16;11:683733. Epub 2021 Jun 16.

Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, Beijing, China.

Purpose: This study was to propose and validate an efficient and streamlined quality assurance (QA) method with a single phantom setup to check performances of patient positioning guidance systems including six-degree-of-freedom (6DoF) couch, X-ray modalities (kV-kV, MV-MV and CBCT), optical surface imaging system (AlignRT), lasers and optical distance indicator (ODI).

Methods And Materials: The QA method was based on a pseudo-patient treatment plan using the AlignRT cube phantom. The cube was first randomly set up on the couch, and the initial position offsets were acquired by AlignRT and CBCT. Read More

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Visual Localisation for Knee Arthroscopy.

Int J Comput Assist Radiol Surg 2021 Jul 4. Epub 2021 Jul 4.

QUT Centre for Robotics, Queensland University of Technology, Brisbane, 4000, Australia.

PURPOSE  : Navigation in visually complex endoscopic environments requires an accurate and robust localisation system. This paper presents the single image deep learning based camera localisation method for orthopedic surgery. METHODS  : The approach combines image information, deep learning techniques and bone-tracking data to estimate camera poses relative to the bone-markers. Read More

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Treatment planning and 4D robust evaluation strategy for proton therapy of lung tumors with large motion amplitude.

Med Phys 2021 Jul 2. Epub 2021 Jul 2.

Department of Radiation Oncology (MAASTRO), GROW - School for Oncology, Maastricht University Medical Centre+, Maastricht, Netherlands.

Purpose: Intensity-modulated proton therapy (IMPT) for lung tumors with a large tumor movement is challenging due to loss of robustness in the target coverage. Often an upper cut-off at 5-mm tumor movement is used for proton patient selection. In this study, we propose (1) a robust and easily implementable treatment planning strategy for lung tumors with a movement larger than 5 mm, and (2) a four-dimensional computed tomography (4DCT) robust evaluation strategy for evaluating the dose distribution on the breathing phases. Read More

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Evaluation of two-dimensional electronic portal imaging device using integrated images during volumetric modulated arc therapy for prostate cancer.

Rep Pract Oncol Radiother 2021 14;26(2):281-290. Epub 2021 Apr 14.

Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan.

Background: The aim of the study was to evaluate analysis criteria for the identification of the presence of rectal gas during volumetric modulated arc therapy (VMAT) for prostate cancer patients by using electronic portal imaging device (EPID)-based dosimetry (IVD).

Materials And Methods: All measurements were performed by determining the cumulative EPID images in an integrated acquisition mode and analyzed using PerFRACTION commercial software. Systematic setup errors were simulated by moving the anthropomorphic phantom in each translational and rotational direction. Read More

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Residual Set Up Errors of the Surrogate-guided Registration Using Four-dimensional CT Images and Breath Holding Ones in Respiratory Gated Radiotherapy for Liver Cancer.

In Vivo 2021 Jul-Aug;35(4):2089-2098

Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan.

Background/aim: To evaluate the surrogate-guided registration accuracy of two computed tomography (CT) image sets, expiratory phase four-dimensional (Ex4D) CT and breath-holding CT (BHCT), in respiratory-gated radiotherapy for liver cancer.

Materials And Methods: The surrogate-guided registration errors were defined as the differences between the diaphragm- and fiducial-guided registrations or the differences between upper and lower fiducial registrations in three directions: left-right (LR), anterior-posterior (AP), and cranio-caudal (CC).

Results: The mean±SDs of the absolute errors for diaphragm-guided registration were 1. Read More

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Development and Accuracy Evaluation of Augmented Reality-based Patient Positioning System in Radiotherapy: A Phantom Study.

In Vivo 2021 Jul-Aug;35(4):2081-2087

Department of Radiology, Hyogo College of Medicine, Hyogo, Japan.

Background/aim: To develop and evaluate the accuracy of augmented reality (AR)-based patient positioning systems in radiotherapy.

Materials And Methods: AR head-mounted displays (AR-HMDs), which virtually superimpose a three-dimensional (3D) image generated by the digital imaging and communications in medicine (DICOM) data, have been developed. The AR-based positioning feasibility was evaluated. Read More

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Estimation of delivered dose to lung tumours considering setup uncertainties and breathing motion in a cohort of patients treated with stereotactic body radiation therapy.

Phys Med 2021 Jun 25;88:53-64. Epub 2021 Jun 25.

Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden; Department of Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Stockholm, Sweden. Electronic address:

Introduction: Dose-response relationships for local control of lung tumours treated with stereotactic body radiotherapy (SBRT) have proved ambiguous, however, these have been based on the prescribed or planned dose. Delivered dose to the target may be a better predictor for local control. In this study, the probability of the delivered minimum dose to the clinical target volume (CTV) in relation to the prescribed dose was estimated for a cohort of patients, considering geometrical uncertainties. Read More

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Noncovalent Interactions by the Quantum Monte Carlo Method: Strong Influence of Isotropic Jastrow Cutoff Radii.

J Chem Theory Comput 2021 Jul 25;17(7):4242-4249. Epub 2021 Jun 25.

Department of Physics, Faculty of Science, University of Ostrava, 30. dubna 22, 701 03 Ostrava, Czech Republic.

We present a paradigmatic example of a strong effect of Jastrow cutoff radii setup on the accuracy of noncovalent interaction energy differences within one-determinant Slater-Jastrow fixed-node diffusion Monte Carlo (1FNDMC) simulations using isotropic Jastrow terms and effective-core potentials. Analysis of total energies, absolute and relative errors, and local energy variance of energy differences vs the reference results suggests a simple procedure to marginalize the related biases. The presented data showcase improvements in dispersion-bounded systems within such a 1FNDMC method. Read More

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Training Surgeons to Perform Arthroscopic All-Inside Meniscal Repair: A Randomized Controlled Trial Evaluating the Effectiveness of a Novel Cognitive Task Analysis Teaching Tool, Imperial College London/University College London Meniscus Repair Cognitive Task Analysis (IUMeRCTA).

Am J Sports Med 2021 Jul 24;49(9):2341-2350. Epub 2021 Jun 24.

Department of Surgery and Cancer, Imperial College London, London, UK.

Background: All-inside meniscal repair is an increasingly common technique for the surgical treatment of meniscal tears. There are currently no standardized techniques for training residents in this procedure. Cognitive task analysis (CTA) is a method of analyzing and standardizing key steps in a procedure that allows training to be conducted in a validated and reproducible manner. Read More

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Distortion correction for particle image velocimetry using multiple-input deep convolutional neural network and Hartmann-Shack sensing.

Opt Express 2021 Jun;29(12):18669-18687

Aberrations degrade the accuracy of quantitative, imaging-based measurements, like particle image velocimetry (PIV). Adaptive optical elements can in principle correct the wavefront distortions, but are limited by their technical specifications. Here we propose an actuator-free correction based on a multiple-input deep convolutional neural network which uses an additional input from a wavefront sensor to correct time-varying distortions. Read More

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Radiobiological evaluation considering setup error on single-isocenter irradiation in stereotactic radiosurgery.

J Appl Clin Med Phys 2021 Jul 20;22(7):266-275. Epub 2021 Jun 20.

Department of Radiology and Radiation Oncology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.

Purpose: We calculated the dosimetric indices and estimated the tumor control probability (TCP) considering six degree-of-freedom (6DoF) patient setup errors in stereotactic radiosurgery (SRS) using a single-isocenter technique.

Methods: We used simulated spherical gross tumor volumes (GTVs) with diameters of 1.0 cm (GTV 1), 2. Read More

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A novel restricted single-isocenter stereotactic body radiotherapy (RESIST) method for synchronous multiple lung lesions to minimize setup uncertainties.

Med Dosim 2021 Jun 17. Epub 2021 Jun 17.

Medical Physics Graduate Program, Department of Radiation Oncology, University of Kentucky, Lexington KY, USA.

Treating multiple lung lesions synchronously using a single-isocenter volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) plan can improve treatment efficiency and patient compliance. However, due to set up uncertainty, aligning multiple lung tumors on a single daily cone beam CT (CBCT) image has shown clinically unacceptable loss of target(s) coverage. Herein, we propose a Restricted Single-Isocenter Stereotactic Body Radiotherapy (RESIST), an alternative treatment that mitigates patient setup uncertainties. Read More

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Error analysis of channeled Stokes polarimeters.

Appl Opt 2021 Jun;60(16):4511-4518

This work presents an analysis of passive polarimeters with spectral channeling, referred to as Stokes channeled spectropolarimeters (SCS). The SCS setup comprises two thick birefringent retarders, followed by a horizontal linear polarizer. The simulation of these polarimeters and two extraction methods for the incident Stokes vector is presented as well. Read More

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Automated capture-based NGS workflow: one thousand patients experience in a clinical routine framework.

Diagnosis (Berl) 2021 Jun 16. Epub 2021 Jun 16.

Department of Laboratory Medicine and Pathology, Diagnostic Hematology and Clinical Genomics Unit, Modena University Hospital, Modena, Italy.

Objectives: The Next Generation Sequencing (NGS) based mutational study of hereditary cancer genes is crucial to design tailored prevention strategies in subjects with different hereditary cancer risk. The ease of amplicon-based NGS library construction protocols contrasts with the greater uniformity of enrichment provided by capture-based protocols and so with greater chances for detecting larger genomic rearrangements and copy-number variations. Capture-based protocols, however, are characterized by a higher level of complexity of sample handling, extremely susceptible to human bias. Read More

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Study of Spinal Cord Substructure Expansion Margin in Esophageal Cancer.

Technol Cancer Res Treat 2021 Jan-Dec;20:15330338211024559

Department of Radiation Oncology, 571884The Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou, Henan, China.

Purpose: To analyze the setup errors and residual errors of different spinal cord parts in esophageal cancer patients and to explore the necessity of spinal cord segmental expansion.

Methods And Materials: Sixty cases of esophageal cancer were included with 20 patients subdivided into the following groups: neck, chest and abdomen as per the treatment site. The patients underwent intensity modulated radiation therapy (IMRT) between 2017 and 2019. Read More

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Organ motion in linac-based SBRT for glottic cancer.

Radiat Oncol 2021 Jun 12;16(1):106. Epub 2021 Jun 12.

Department of Radiation Oncology, IRCSS Regina Elena National Cancer Institute, Rome, Italy.

Purpose: The purpose of this study is to evaluate inter- and intra-fraction organ motion as well as to quantify clinical target volume (CTV) to planning target volume (PTV) margins to be adopted in the stereotactic treatment of early stage glottic cancer.

Methods And Materials: Stereotactic body radiotherapy (SBRT) to 36 Gy in 3 fractions was administered to 23 patients with early glottic cancer T1N0M0. Patients were irradiated with a volumetric intensity modulated arc technique delivered with 6 MV FFF energy. Read More

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An Adaptable Computed Tomography-Derived Three-Dimensional-Printed Alignment Fixture Minimizes Errors in Radius Biomechanical Testing.

J Biomech Eng 2021 Nov;143(11)

Department of Mechanical Engineering & Mechanics, Packard Laboratory, Lehigh University, 19 Memorial Drive West, Bethlehem, PA 18015.

Biomechanical testing of long bones can be susceptible to errors and uncertainty due to malalignment of specimens with respect to the mechanical axis of the test frame. To solve this problem, we designed a novel, customizable alignment and potting fixture for long bone testing. The fixture consists of three-dimensional-printed components modeled from specimen-specific computed tomography (CT) scans to achieve a predetermined specimen alignment. Read More

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November 2021