Article
Chemistry, Physical
Stalyn Mutsakanyi, Freek du Plessis
Summary: This study focused on the dosimetric characterization of clinical electron beams shaped by an Elekta Synergy linear accelerator with a 160 leaf Agility MLC, showing potential for application in Modulated Electron Radiation Therapy. Results indicated improved efficiency in treatment with faster completion and better dose distribution.
RADIATION PHYSICS AND CHEMISTRY
(2021)
Article
Physics, Multidisciplinary
Me Young Kim, Jai-Woong Yoon, Kwang-Ho Cheong, Sei-Kwon Kang, Taeryool Koo, Kyoung Ju Kim, Soah Park
Summary: This study aimed to evaluate the usefulness of MLC and jaw shielding in the MLB plan for cervical cancer treatment. The shape of the MLC opening was considered to close the jaw or diaphragm, depending on the Linac used. The radiation dose to unintended areas was evaluated using the Exradin A19 Ion Chamber and calibrated EBT3 film. The results showed dose leakage in both Linac types, but using shielded fields reduced the dose to the rectum and bladder.
JOURNAL OF THE KOREAN PHYSICAL SOCIETY
(2023)
Article
Radiology, Nuclear Medicine & Medical Imaging
Christina Stengl, Eric Arbes, Long-Yang Jan Thai, Gernot Echner, Jose Vedelago, Jeannette Jansen, Oliver Jaekel, Joao Seco
Summary: In this study, a versatile and low-cost mini-beam collimator was designed and manufactured for pre-clinical applications with X-ray beams. The collimator allows the adjustment of various parameters such as full width at half maximum, center-to-center distance, peak-to-valley dose ratio and source-to-collimator distance. Dosimetric measurements confirmed the accuracy of the designed mini-beam dose distributions, and the collimator was able to deliver and quantify mini-beam dose distribution patterns in vitro.
Article
Nuclear Science & Technology
Taylan Tugrul
Summary: In this study, we investigated the effect of tongue-and-groove on irregular fields and intensity-modulated radiotherapy plan, as well as the depth dependence of the tongue-and-groove effect. We found consistent results of the tongue-and-groove effect in both measurements, with a calculated dose reduction between 6% and 14%. The tongue-and-groove effect decreased as the depth increased. Although the effect did not significantly impact the dose distribution in multi-field use, it could occur at the edge of the field, highlighting the importance of examining dose differences due to multileaf collimator structure and the consideration of these effects in treatment planning systems.
RADIATION EFFECTS AND DEFECTS IN SOLIDS
(2023)
Article
Radiology, Nuclear Medicine & Medical Imaging
Maude Gondre, Fanny Marsolat, Jean Bourhis, Francois Bochud, Raphael Moeckli
Summary: The study commissioned and evaluated the MC dose calculation algorithm for CyberKnife with MLC, showing good agreement in measurements but underestimating the delivered dose by an average of 1.5%. The MC model is recommended for use in heterogeneous regions and shallow-seated tumors.
JOURNAL OF APPLIED CLINICAL MEDICAL PHYSICS
(2022)
Article
Radiology, Nuclear Medicine & Medical Imaging
Sae Nakamura, Madoka Sakai, Natsuki Ishizaka, Kazuki Mayumi, Tomotaka Kinoshita, Shinya Akamatsu, Takayuki Nishikata, Shunpei Tanabe, Hisashi Nakano, Satoshi Tanabe, Takeshi Takizawa, Takumi Yamada, Hironori Sakai, Motoki Kaidu, Ryuta Sasamoto, Hiroyuki Ishikawa, Satoru Utsunomiya
Summary: This study successfully created and evaluated deep learning-based models to detect and classify errors in multi-leaf collimator modeling parameters in volumetric modulated radiation therapy (VMAT). The accuracy of the models depends on the magnitude of the errors, treatment site, and the degree of mimicked measurement doses.
JOURNAL OF APPLIED CLINICAL MEDICAL PHYSICS
(2023)
Article
Oncology
Diana Grishchuk, Alexis Dimitriadis, Arjun Sahgal, Antonio De Salles, Laura Fariselli, Rupesh Kotecha, Marc Levivier, Lijun Ma, Bruce E. Pollock, Jean Regis, Jason Sheehan, John Suh, Shoji Yomo, Ian Paddick
Summary: This literature review aimed to develop ISRS consensus technical guidelines for the treatment of small (<= 1 cm) intracranial metastases with stereotactic radiosurgery. The review included a systematic analysis of 81 relevant papers and 7 international guidelines, covering areas such as imaging specifications, target volume delineation, margin usage, treatment planning techniques, and patient positioning. The review concluded that SRS can be safely performed on GK, CK, and modern LINACs, but requires expertise and resources based on the latest evidence.
PRACTICAL RADIATION ONCOLOGY
(2023)
Article
Radiology, Nuclear Medicine & Medical Imaging
Veng Jean Heng, Monica Serban, Jan Seuntjens, Marc-Andre Renaud
Summary: The study successfully validated the delivery process of mixed electron-photon radiation therapy (MBRT) on a Varian TrueBeam accelerator and laid the foundation for a patient-specific quality assurance (QA) protocol based on ion chamber point measurements and 2D film measurements. The results showed good agreement between measured and simulated MBRT doses, indicating that the dose distributions obtained from the MBRT treatment planning algorithm are achievable in practice. Further investigation is needed to confirm the accuracy of ionization chamber correction factors kMBRT calculations at low electron energies.
Article
Engineering, Biomedical
Emily A. Hewson, Doan Trang Nguyen, Andrew Le, Jeremy T. Booth, Paul J. Keall, Lars Mejnertsen
Summary: A dose-optimised multi-target MLC tracking method was developed to minimize errors in the treatment of locally advanced prostate cancer. It showed better performance compared to geometric-optimised tracking and no tracking.
PHYSICS IN MEDICINE AND BIOLOGY
(2022)
Article
Multidisciplinary Sciences
Evelien de Greef, Alexander Suh, Matt J. Thorstensen, Kira E. Delmore, Kevin C. Fraser
Summary: The impact of climate change on spring phenology is a risk for migratory birds controlled by endogenous mechanisms. The genetic basis and genomic regions associated with migration timing phenotypes in wild individuals need further investigation. This study examined the genetic architecture of migration timing in purple martins by integrating genomic data and direct migratory tracks, finding a significant genetic component and potential genes associated with nocturnal flights and epigenetic modifications on chromosome 1.
SCIENTIFIC REPORTS
(2023)
Article
Engineering, Biomedical
Gian Guyer, Silvan Mueller, Paul-Henry Mackeprang, Daniel Frei, Werner Volken, Daniel M. Aebersold, Kristina Loessl, Peter Manser, Michael K. Fix
Summary: An effective treatment planning process (TPP) for Arc-MBRT was developed and showed the potential to improve plan quality while maintaining short delivery times compared to Static-MBRT. This has significance in integrating pMLC-based MBRT into clinical practice.
PHYSICS IN MEDICINE AND BIOLOGY
(2023)
Article
Nuclear Science & Technology
Ning Tang, Chun-dong Hu, Yuan-lai Xie, Jiang-long Wei, Zhi-Wei Cui, Jun-Wei Xie, Zhuo Pan, Yao Jiang
Summary: This paper calculates the heat load distribution of the collimator through experimental data and conducts transient thermodynamic simulation analysis. The optimized model improves the heat transfer performance and reduces the maximum temperature. Steady-state simulations are performed to adapt to long-pulse steady-state operation. The research provides reference for the design of components under high-energy and long-pulse operational conditions.
NUCLEAR ENGINEERING AND TECHNOLOGY
(2022)
Article
Radiology, Nuclear Medicine & Medical Imaging
W. Hoegele, P. Zygmanski
Summary: This study introduces a new detector, SDA, for monitoring MLC shaped x-ray beams in radiotherapy. The SDA demonstrates accurate reconstruction of MLC leaf positions and Monitor Units, making it suitable for real-time Quality Control.
BIOMEDICAL PHYSICS & ENGINEERING EXPRESS
(2022)
Article
Oncology
Emily A. Hewson, Andrew Dipuglia, John Kipritidis, Yuanyuan Ge, Ricky O'Brien, Stephanie Roderick, Linda Bell, Per R. Poulsen, Thomas Eade, Jeremy T. Booth, Paul J. Keall, Doan T. Nguyen
Summary: This study demonstrates the first experimental implementation of real-time multi-target tracking system for locally advanced prostate cancer, which shows significant reduction in dosimetric and geometric errors compared to single-target tracking and no tracking.
RADIOTHERAPY AND ONCOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Hongsheng Liu, Ruilei Xue, Jianping Zhou, Yang Bao, Xiaojuan Li
Summary: This study proposes a two-stage algorithm to achieve seam tracking and oscillation width adaptation in NG-GMAW pipeline welding using principal component analysis (PCA) eigenvectors. Experimental results show that the proposed scheme can achieve seam tracking and oscillation width adaptation with an accuracy of 0.1 mm.
SCIENCE AND TECHNOLOGY OF WELDING AND JOINING
(2023)
Article
Radiology, Nuclear Medicine & Medical Imaging
Monchai Phonlakrai, Saadallah Ramadan, John Simson, Neda Golizda, Jameen Arm, Kate Skehan, Jonathan Goodwin, Yuvnik Trada, Jarad Martin, Swetha Sridharan, Bishnu Lamichhane, Steven Bollipo, Peter Greer
Summary: This study aimed to investigate the feasibility of voxel-based hepatic extraction fraction (HEF) quantification using low-temporal resolution (LTR) dynamic contrast-enhanced MRI for liver sparing radiotherapy. The results showed that the implemented method accurately reproduced simulated liver function. HEF could distinguish between different grades of liver function impairment and may be used for functional guidance in radiotherapy.
JOURNAL OF MEDICAL RADIATION SCIENCES
(2023)
Article
Oncology
Tokihiro Yamamoto, Sven Kabus, Matthieu Bal, Paul J. Keall, Angel Moran, Cari Wright, Stanley H. Benedict, Devin Holland, Nichole Mahaffey, Lihong Qi, Megan E. Daly
Summary: The study aimed to assess the safety and feasibility of lung functional avoidance radiation therapy (RT) using 4-dimensional (4D) computed tomography (CT) ventilation imaging. The results demonstrated that functional avoidance RT significantly reduced the dose to ventilated lung regions and was safe and feasible.
INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS
(2023)
Article
Radiology, Nuclear Medicine & Medical Imaging
Chandrima Sengupta, Simon Skouboe, Thomas Ravkilde, Per Rugaard Poulsen, Doan Trang Nguyen, Peter B. Greer, Trevor Moodie, Nicholas Hardcastle, Amy J. Hayden, Sandra Turner, Shankar Siva, Keen-Hun Tai, Jarad Martin, Jeremy T. Booth, Ricky O'Brien, Paul J. Keall
Summary: This study quantified the dosimetric impact of intrafraction prostate rotation on the delivery of radiation therapy. The results suggest that the standard CTV-PTV margin is sufficient to account for the observed rotation, and residual dose errors due to uncorrected rotation can be minimized with different treatment adaptation strategies to improve dosimetric accuracy.
Article
Radiology, Nuclear Medicine & Medical Imaging
David E. J. Waddington, Nicholas Hindley, Neha Koonjoo, Christopher Chiu, Tess Reynolds, Paul Z. Y. Liu, Bo Zhu, Danyal Bhutto, Chiara Paganelli, Paul J. J. Keall, Matthew S. S. Rosen
Summary: Research shows that using deep learning techniques for real-time MRI data reconstruction can improve the accuracy of tumor tracking and reduce damage to healthy tissues. By utilizing the AUTOMAP neural network for fast reconstruction, equivalent accuracy to traditional methods can be achieved in a shorter processing time.
Article
Radiology, Nuclear Medicine & Medical Imaging
Brendan Whelan, Billy W. W. Loo Jr, Jinghui Wang, Paul Keall
Summary: This study describes and tests TopasOpt, a free, open-source and extensible library for mathematical optimization of Monte Carlo simulations in Topas. TopasOpt allows any Topas model to be transformed into an optimization problem and any parameter within the model to be treated as an optimization variable. Three case studies are presented to validate the tool, showing improved accuracy and efficiency in Monte Carlo simulations.
Article
Radiology, Nuclear Medicine & Medical Imaging
Jae Hyuk Choi, Behzad Asadi, John Simpson, Jason A. Dowling, Stephan Chalup, James Welsh, Peter Greer
Summary: The purpose of this study is to provide a metric that reflects the dosimetric utility of synthetic CT (sCT) and can be rapidly determined. Image similarity measurements and automatic determination of water equivalent depth (WED) were conducted and compared with the isocentre dose difference (ADiso) between the two scans. The results showed that AWED is highly correlated with ADiso, and it can facilitate the process of developing and evaluating new sCT generation algorithms.
PHYSICA MEDICA-EUROPEAN JOURNAL OF MEDICAL PHYSICS
(2023)
Article
Engineering, Biomedical
P. B. Greer, T. Standen, R. David, N. Miri, K. Bobrowski, J. Lehmann, B. Zwan, A. Moore
Summary: The objective of this study was to develop and validate a method for remote dosimetric auditing that compares dose-volume histogram parameters of measured and planned dose in the patient CT volume. The method combines a remote electronic portal imaging (EPID) based auditing method and a method to estimate 3D in-patient dose distributions from planar dosimetric measurements. The method was tested with error-induced plans and showed promising results in reproducing dose errors and detecting small positioning errors. The audit method provides clinically meaningful DVH metrics and improves the understanding of a center's radiotherapy quality.
PHYSICS IN MEDICINE AND BIOLOGY
(2023)
Article
Engineering, Biomedical
Guneet Kaur, Joerg Lehmann, Peter B. Greer, Jarad Martin, John Simpson
Summary: This study quantified the performance of IMR during prostate SBRT treatments and evaluated its impact on treatment. The results showed that IMR has good accuracy and real-time capability, significantly improving target dose coverage. The use of the Default Search Region method can better detect clinically relevant prostate motion.
PHYSICAL AND ENGINEERING SCIENCES IN MEDICINE
(2023)
Article
Radiology, Nuclear Medicine & Medical Imaging
Abdella M. Ahmed, Maegan Gargett, Levi Madden, Adam Mylonas, Danielle Chrystall, Ryan Brown, Adam Briggs, Trang Nguyen, Paul Keall, Andrew Kneebone, George Hruby, Jeremy Booth
Summary: This study evaluated three deep learning frameworks for marker tracking in pancreas SBRT. The results showed that the DL models predicted marker positions with submillimeter accuracy compared to the ground truth data, and the detection times were fast enough to meet the requirements for real-time application.
BIOMEDICAL PHYSICS & ENGINEERING EXPRESS
(2023)
Article
Radiology, Nuclear Medicine & Medical Imaging
Mark Gardner, Youssef Ben Bouchta, Adam Mylonas, Marco Mueller, Chen Cheng, Phillip Chlap, Robert Finnegan, Jonathan Sykes, Paul J. Keall, Doan Trang Nguyen
Summary: This study aims to develop a method for detecting and segmenting head and neck tumors during radiation therapy (RT). A conditional generative adversarial network (cGAN) was used to detect and segment tumors in kV images acquired during RT. The method showed high accuracy in segmenting the tumors, demonstrating its feasibility for H&N cancer patients during RT.
Article
Engineering, Biomedical
Danielle Chrystall, Adam Mylonas, Emily Hewson, Jarad Martin, Paul Keall, Jeremy Booth, Doan Trang Nguyen
Summary: This study developed a novel real-time marker tracking system based on a convolutional neural network classifier. The system achieved high classification performance and sub-millimeter accuracy in tracking markers on MV images. This has significant potential for real-time image guided radiation therapy.
PHYSICS IN MEDICINE AND BIOLOGY
(2023)
Article
Medicine, Research & Experimental
Hilary L. Byrne, Elisabeth Steiner, Jeremy Booth, Gillian Lamoury, Marita Morgia, Kylie Richardson, Leigh Ambrose, Kuldeep Makhija, Cameron Stanton, Benjamin Zwan, Regina Bromley, John Atyeo, Shona Silvester, Natalie Plant, Paul Keall
Summary: The BRAVEHeart trial aims to evaluate the accuracy and usability of a novel device, Breathe Well, for guiding deep inspiration breath hold (DIBH) in left-sided breast cancer patients. Compared to the existing monitoring system RPM, Breathe Well has higher accuracy in monitoring chest wall motion and can help reduce cardiac dose during radiotherapy.
Article
Radiology, Nuclear Medicine & Medical Imaging
Yuvnik Trada, Peter Lin, Mark T. Lee, Michael G. Jameson, Phillip Chlap, Paul Keall, Daniel Moses, Allan Fowler
Summary: This study evaluated the impact of different ROI delineation methods on FDG-PET response prediction in mucosal head and neck squamous cell carcinoma during radiotherapy. The findings suggest that using a gradient-based method is preferable for assessing volumetric tumour response and predicting treatment outcomes compared to threshold-based methods.
QUANTITATIVE IMAGING IN MEDICINE AND SURGERY
(2023)