Evaluation and mitigation of deformable image registration uncertainties for MRI‐guided adaptive radiotherapy
AAPM
by Hualiang Zhong, Kristofer K. Kainz, Eric S. Paulson
20h ago
Abstract Purpose We evaluate the performance of a deformable image registration (DIR) software package in registering abdominal magnetic resonance images (MRIs) and then develop a mechanical modeling method to mitigate detected DIR uncertainties. Materials and Methods Three evaluation metrics, namely mean displacement to agreement (MDA), DICE similarity coefficient (DSC), and standard deviation of Jacobian determinants (STD-JD), are used to assess the multi-modality (MM), contour-consistency (CC), and image-intensity (II)-based DIR algorithms in the MIM software package, as well as an in-house ..read more
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The impact of advancing the standard of care in radiotherapy on operational treatment resources
AAPM
by Michael Roumeliotis, Kundan Thind, Hali Morrison, Ben Burke, Kevin Martell, Lukas van Dyke, Lisa Barbera, Sarah Quirk
20h ago
Abstract Purpose To demonstrate the impact of implementing hypofractionated prescription regimens and advanced treatment techniques on institutional operational hours and radiotherapy personnel resources in a multi-institutional setting. The study may be used to describe the impact of advancing the standard of care with modern radiotherapy techniques on patient and staff resources. Methods This study uses radiation therapy data extracted from the radiotherapy information system from two tertiary care, university-affiliated cancer centers from 2012 to 2021. Across all patients in the analysis ..read more
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First implementation of an innovative infra‐red camera system integrated into a mobile CBCT scanner for applicator tracking in brachytherapy—Initial performance characterization
AAPM
by Andre Karius, Lisa Marie Leifeld, Vratislav Strnad, Rainer Fietkau, Christoph Bert
3d ago
Abstract Purpose To enable a real-time applicator guidance for brachytherapy, we used for the first time infra-red tracking cameras (OptiTrack, USA) integrated into a mobile cone-beam computed tomography (CBCT) scanner (medPhoton, Austria). We provide the first description of this prototype and its performance evaluation. Methods We performed assessments of camera calibration and camera-CBCT registration using a geometric calibration phantom. For this purpose, we first evaluated the effects of intrinsic parameters such as camera temperature or gantry rotations on the tracked marker positions ..read more
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Novel utilization and quantification of Xsight diaphragm tracking for respiratory motion compensation in Cyberknife Synchrony treatment of liver tumors
AAPM
by Jianping Zhang, Lin Wang, Chenyu Xie, Zhiyu Yang, Benhua Xu, Xiaobo Li
3d ago
Abstract Purpose The Xsight lung tracking system (XLTS) utilizes an advanced image processing algorithm to precisely identify the position of a tumor and determine its location in orthogonal x-ray images, instead of finding fiducials, thereby minimizing the risk of fiducial insertion-related side effects. To assess and gauge the effectiveness of CyberKnife Synchrony in treating liver tumors located in close proximity to or within the diaphragm, we employed the Xsight diaphragm tracking system (XDTS), which was based on the XLTS. Methods We looked back at the treatment logs of 11 patients (8/11 ..read more
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Characterization of a novel VenusX orthogonal dual‐layer multileaf collimator
AAPM
by Qingxin Wang, Qifeng Li, Zhongqiu Wang, Chengwen Yang, Daguang Zhang, Jun Wang, Ping Wang, Wei Wang
3d ago
Abstract Purpose To investigate and characterize the performance of a novel orthogonal dual-layer alpha multileaf collimator (αMLC) mounted on the LinaTech VenusX linac. Methods We evaluated leaf positioning accuracy and reproducibility using an electronic portal imaging device through the picket fence test. The average, interleaf, intraleaf, and leaf tip transmissions of the single and dual layers were measured using an ionization chamber. Square and rhombus fields were used to evaluate the leaf penumbra of αMLC. To investigate the advantages of the orthogonal dual-layer multileaf collimator ..read more
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Implementation of a programmatic assessment model in radiation oncology medical physics training
AAPM
by Cathy Barbagallo, Kristy Osborne, Claire Dempsey
3d ago
Abstract Purpose In 2019, a formal review and update of the current training program for medical physics residents/registrars in Australasia was conducted. The purpose of this was to ensure the program met current local clinical and technological requirements, to improve standardization of training across Australia and New Zealand and generate a dynamic curriculum and programmatic assessment model. Methods A four-phase project was initiated, including a consultant desktop review of the current program and stakeholder consultation. Overarching program outcomes on which to base the training mode ..read more
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Design and implementation of automated notification systems and an electronic whiteboard for radiation therapy planning monitoring
AAPM
by Ping Yan, Jin Shen, Amar Basavatia, Madhur K. Garg, Wolfgang A. Tomé
3d ago
Abstract Purpose Radiotherapy (RT) treatment and treatment planning is a complex process prepared and delivered by a multidisciplinary team of specialists. Efficient communication and notification systems among different team members are therefore essential to ensure the safe, timely delivery of treatments to patients. Method To address this issue, we developed and implemented automated notification systems and an electronic whiteboard to track every CT simulation, contouring task, the new-start schedule, and physician's appointments and tasks, and notify team members of overdue and missing ta ..read more
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Physician scatter dose in interventional CT fluoroscopy
AAPM
by Emily A. Knott, Jonathan L. Troville, Carlos Alberto Reynoso, Sean D. Rose, Martin G. Wagner, Fred T. Lee Jr., Jeffery L. Radtke, Daniel R. Anderson, Annie Zlevor, Meghan G. Lubner, J. Louis Hinshaw, Timothy P. Szczykutowicz
3d ago
Abstract Purpose To quantify operator dose in interventional CT fluoroscopy (CTF) procedures and compare to catheterization laboratory and interventional radiology procedures. Methods Fifteen studies quantifying operator scatter dose for c-arm fluoroscopy and CTF were reviewed from a literature survey. The dose provided in each study was normalized to skin entrance air kerma and air kerma rate including backscatter. The average air kerma rate and exposure duration were calculated and compared between c-arm fluoroscopy and CTF. To enable operator scatter dose calculations in CTF procedures, a m ..read more
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Evaluating automatically generated normal tissue contours for safe use in head and neck and cervical cancer treatment planning
AAPM
by Raphael Douglas, Adenike Olanrewaju, Raymond Mumme, Lifei Zhang, Beth M. Beadle, Laurence Edward Court
6d ago
Abstract Purpose Volumetric-modulated arc therapy (VMAT) is a widely accepted treatment method for head and neck (HN) and cervical cancers; however, creating contours and plan optimization for VMAT plans is a time-consuming process. Our group has created an automated treatment planning tool, the Radiation Planning Assistant (RPA), that uses deep learning models to generate organs at risk (OARs), planning structures and automates plan optimization. This study quantitatively evaluates the quality of contours generated by the RPA tool. Methods For patients with HN (54) and cervical (39) cancers ..read more
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Monte Carlo evaluation of uncertainties in photon and electron TG‐51 absorbed dose calibration
AAPM
by Patrick N. McDermott
6d ago
Abstract Purpose The accuracy of dose delivery to all patients treated with medical linacs depends on the accuracy of beam calibration. Dose delivery cannot be any more accurate than this. Given the importance of this, it seems worthwhile taking another look at the expected uncertainty in TG-51 photon dose calibration and a first look at electron calibration. This work builds on the 2014 addendum to TG-51 for photons and adds to it by also considering electrons. In that publication, estimates were made of the uncertainty in the dose calibration. In this paper, we take a deeper look at this imp ..read more
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