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Results for "central axis": 35 found

3D Renal Microdosimetry: Evaluating Radiopharmaceuticals Using Histology-Based 3D Models

Authors: John P. Aris, Wesley E. Bolch, Madison Bushloper, Lauren E Ellis, Adam Grey Haneberg, Elizabeth Martin, Bonnie N. C. President, Andrew Robert Sforza, Alexander Zorrilla

Affiliation: Johns Hopkins University, Biomedical Engineering, University of Florida

Abstract Preview: Purpose: To develop six additional high-fidelity 3D models of kidney renal cortical labyrinth from H&E-stained histology slides to support radiation dosimetry in radiopharmaceutical therapies (RPTs).<...

A Novel 3D Printed Tool to Enable Faster More Accurate Patient Positioning for Electron Radiotherapy

Authors: Christopher J. Mart, Daniel G. McDonald, Inna V. McGowin, Sean A. Roles

Affiliation: Medical University of South Carolina

Abstract Preview: Purpose: To improve the efficiency and accuracy of the positioning process for electron treatments by providing a pointer system for patient alignment to central axis (CAX) of the field at the correct...

An Analytical Approach to Monitor Unit Calculation in Extended Distance Total Body Irradiation (TBI)

Authors: Cheewai Cheng, Indra J. Das, Jeffrey Yui Hei Wong, Poonam Yadav

Affiliation: Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine

Abstract Preview: Purpose: Radiation treatment machine replacement brings chaos and urgency of timely completion of machine commissioning for every procedure used including TBI that are time consuming. Based on past ex...

Automated Parametric Custom Collimator Creation for Preclinical Irradiation Studies

Authors: Muhammad Ramish Ashraf, Dixin Chen, Lloyd Emmanuel Kamole Ghomsi, Edward Elliot Graves, Billy W Loo, Stavros Melemenidis, Joseph B. Schulz, Lawrie Skinner

Affiliation: Department of Radiation Oncology, Department of Radiation Oncology, Stanford University School of Medicine

Abstract Preview: Purpose: Precise beam collimation is essential in preclinical radiotherapy studies to ensure accurate dose delivery. Manual design and fabrication of organ-specific collimators usually consist of mult...

Automatic 4D Lung PET-CT Segmentation Using Hybrid Deep Neural Network

Authors: Hongyi Jiang, Fang-Fang Yin

Affiliation: Duke University, Medical Physics Graduate Program, Duke Kunshan University

Abstract Preview: Purpose:
Imaging moving tissues using PET-CT can be difficult. Separating signal into phases during construction reduces signal count and increases influence of noise. Algorithms that use signal fr...

Calibration of Dynamic Collimation System Trimmers to Proton Beam Axis Using Gantry-Angle-Specific Corrections: A Look-up Table Solution

Authors: Wesley S. Culberson, Albert Du, Ryan T. Flynn, Ryan Gardner, Alonso N. Gutierrez, Patrick M Hill, Daniel E. Hyer, Blake R. Smith, Nhan Vu, Karsten K. Wake

Affiliation: University of Wisconsin, Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin - Madison, Miami Cancer Institute, Baptist Health South Florida, Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, University of Iowa, Iowa Health Care

Abstract Preview: Purpose: In proton therapy, the substantial size of the gantry introduces sag, causing the proton isocenter to drift as a function of gantry angle. While the scanning magnets correct the beam’s isocen...

Compact Representation of External Beam Photon Phase Space Data Via Implicit Neural Representation Learning

Authors: Serdar Charyyev, Cynthia Fu-Yu Chuang, Veng Jean Heng, Lianli Liu, Lei Xing, Yong Yang

Affiliation: Department of Radiation Oncology, Stanford University

Abstract Preview: Purpose: To replace large finite-size photon phase space files with a compact neural network capable of generating an infinite number of particles.
Methods: Three separate models were developed to ...

Comparison of Mlc Off-Axis Characteristics for Eclipse AAA v18 and v16 Using Portal Dosimetry

Authors: Junsheng Cao, Khushdeep Singh

Affiliation: Overlook Medical Center

Abstract Preview: Purpose: Eclipse v18 introduces Enhanced Leaf Modeling for MLCs. This study investigates the MLC off-axis characteristics using portal dosimetry
Methods:
MLC characteristics were analyzed for th...

Computational Prototype Single-Channel Vaginal Cylinder with Integrated Filter to Address Dose Uniformity in High-Dose-Rate Brachytherapy for Endometrial Cancer

Authors: Brett Bocian, Patrick James Jensen, Luis Augusto Perles, Christopher J. Tien

Affiliation: Yale University School of Medicine, University of Miami, The University of Texas MD Anderson Cancer Center, UT MD Anderson Cancer Center

Abstract Preview: Purpose: Guidelines for dose prescriptions in endometrial cancer are based upon depth from the cylinder, traditionally 5 mm or 0 mm (i.e., surface). There are no current single-channel vaginal cylinde...

Design and Testing of a 3D-Winston-Lutz Phantom to Quantify Isocentricity of Pencil Beam Scanning Proton Therapy Machines

Authors: Imad M. Ali, Nesreen Alsbou, Baraa Kalani

Affiliation: Oklahoma State University, University of Central Oklahoma, University of Oklahoma Health Sciences Center

Abstract Preview: Purpose: To develop a three-dimensional Winston-Lutz phantom to quantify the isocentricity of the gantry, couch, and on-board imager of the MEVION-S250i proton therapy machine.
Methods: A 3D-scinti...

Determine the Isocenter and Its Size for MR Linac Unity Part1: (U V) of Cax

Authors: Ting Chen, Siming Lu, Tanxia Qu, Hesheng Wang

Affiliation: NYU Langone Health

Abstract Preview: Purpose: This study, the first in a two-part series, aims to determine the isocenter position and size for the MR Linac UNITY, focusing on the central axis (CAX) alignment of its Multi-Leaf Collimator...

Determine the Isocenter and Its Size for MR Linac Unity Part2: (u v) of BB and Isocenter Position and Size

Authors: Tanxia Qu, Hesheng Wang

Affiliation: NYU Langone Health

Abstract Preview: Purpose:
This study, the second in a two-part series, evaluates the isocenter position (the point in 3D space minimizing the sum of Euclidean distances to the MLC's central axis) and isocenter size...

Directional Dependence of Detectors for Beam Profiles and Output Factors in Small Field Dosimetry

Authors: Indra J. Das, Ahtesham Ullah Khan, Andrew J. White

Affiliation: Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin - Madison, Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine

Abstract Preview: Purpose: Small field dosimetry presents challenges due to lateral disequilibrium and the selection of suitable detectors. Volume averaging and density corrections hamper accurate profile measurements....

Dose Distribution Analysis for Different Geometries of a Multiple-X-Ray Source Array (MXA) CT Scanner

Authors: Craig K Abbey, John M. Boone, Richard E. Colbeth, Andrew M. Hernandez, Vance Robinson, Paul Schwoebel, Jeffrey H. Siewerdsen, Alejandro Sisniega, Wojciech B. Zbijewski, Huanyi Zhou

Affiliation: UC Santa Barbara, University of California, UT MD Anderson Cancer Center, Johns Hopkins University, University of New Mexico Albuquerque, UC Davis Health, Varex Imaging Corporation

Abstract Preview: Purpose: A Multiple-X-ray Source Array (MXA) for CT (MXA-CT) is under development to mitigate cone beam artifacts in axial CT scans using wide collimation. The purpose of this study is to assess the i...

Dynamic 2.5D Surface Dosimetry Using Deformable Scintillator Array Imaging

Authors: Petr Bruza, Megan Clark, David J. Gladstone, Lesley A Jarvis, Allison Matous, Roman Vasyltsiv, Rongxiao Zhang

Affiliation: Dartmouth Health, Dartmouth College, Thayer School of Engineering, Dartmouth College, Dartmouth Cancer Center, University of Missouri

Abstract Preview: Purpose: On-patient dosimeters assist in clinical decision-making by measuring surface dose, but single-point measurements cannot monitor area-wide distributions and are misleading in high-gradient re...

Effects of Skin Gap and Applicator Tilt on Dose Coverage for Skin Lesions Treatment with Leipzig Applicator

Authors: Awens Alphonse, Nebi Demez, Michael Kasper, Noufal Manthala Padannayil, Shyam Pokharel, Suresh Rana, Lauren A. Rigsby, Nishan Shrestha

Affiliation: Lynn Cancer Institute, Boca Raton Regional Hospital, Baptist Health South Florida

Abstract Preview: Purpose: This study aims to quantify the dose discrepancy associated with improper placement of the Leipzig applicator on the patient's skin.
Methods: Monte Carlo simulations were performed using t...

Electronic Brachytherapy Dosimetric Reference Datasets Using Model-Based Dose Calculation Algorithms

Authors: David Ayala Alvarez, Facundo Ballester, Luc Beaulieu, Francisco Berumen-Murillo, Jean-Simon Cote, Ernesto Mainegra-Hing, Iymad Mansour, Gaël Ndoutoume-Paquet, Rowan M. Thomson, Christian Valdes, Javier Vijande, Peter G. Watson

Affiliation: Département de physique, de génie physique et d'optique, Université Laval, Laval University, Princess Margaret Cancer Centre, McGill University, Department of Physics and Medical Physics Unit, McGill University, IFIC-UV, University of Valencia, National Research Council Canada, Carleton University, 5Service de Physique Médicale et de Radioprotection, Centre Intégré de Cancérologie, CHU de Québec- Université Laval et Centre de recherche du CHU de Québec, Nuclear Medicine Department, Hospital Regional de Antofagasta

Abstract Preview: Purpose: Modelling electronic brachytherapy (eBT) sources is difficult because of the high-dose gradients and challenges associated with low-energy modelling. This study examines the accuracy of avail...

Feasibility and Consistency of a Quad Wedge with a 2D Detector Array for Routine Quality Assurance on a MR-Linac

Authors: Grace Hutchinson, Daniel E. Hyer, Samuel D. Rusu, Blake R. Smith, Joel J. St-Aubin

Affiliation: Iowa Health Care, University of Iowa

Abstract Preview: Purpose: To assess the feasibility and consistency of the Sun Nuclear Corporation (SNC) MR conditional Quad Wedge, as an accessory to the IC Profiler-MR, and to evaluate beam output and energy in the ...

Feasibility of Using a Dynamic-Platform with High-Resolution Patient-Specific QA Device for Periodic and Patient-Specific-QA in Respiratory-Gated Radiotherapy Lung SBRT Treatment

Authors: Tae Kyu Lee

Affiliation: Allina Health

Abstract Preview: Purpose: To assess the feasibility of a dynamic-platform integrated with high-resolution patient-specific-quality-assurance (PSQ device for periodic quality assurance (PQA) and PSQA in respiratory-gat...

HDR End-to-End Testing of Horizontal Leipzig Skin Applicators with Ir-192 Calibrated Oslds

Authors: ChangSeon Kim, Andrew Lukban, Mario Serrano-Sosa, Nadia M. Vassell

Affiliation: Mount Sinai Beth Israel

Abstract Preview: Purpose: Commissioning of Flexitron HDR horizontal Leipzig applicators typically includes indirect or direct output verification, using a well chamber specific Revised Correspondence Factor (CFrev) or...

Impact of Beamline Mis-Adjustment Following Central Beamline Replacement for Halcyon Linear Accelerator

Authors: Emily Y. Hirata, Xiaoyu Sherry Liu, Evan Porter, Manju Sharma

Affiliation: University of California San Francisco, University of California, San Francisco, University of California

Abstract Preview: Purpose: Introduced in 2018, the Varian Halcyon platform has increased in popularity due to its reduced cost, user-friendly design, and operational efficiency. As this platform ages, major repairs, in...

Impact of Breathing Trace on Gating Uncertainty

Authors: William P. Donahue, Lauren Smith, Shu (Stella) Xing

Affiliation: Department of Medical Physics, Memorial Sloan Kettering Cancer Center

Abstract Preview: Purpose: To quantify the dosimetric uncertainty of end-exhale gating as a function of breathing pattern.

Methods: A Truebeam delivered AP square fields to EBT4 film placed in the Quasar MRI4D M...

Impact of Mlc and Collimator Errors in Psqa Techniques for VMAT Breast Treatment Plans

Authors: Maria Jose Almada, Oscar Apaza, Carlos Bohorquez, Ezequiel Cabrera, Rogelio Diaz Moreno, Maximiliano Musso, Rosa Petit, Carlos Daniel Venencia, Lucy D. Wolfsberger

Affiliation: LAP, FaMAF, UNC, Instituto Zunino - Fundacion Marie Curie

Abstract Preview: Purpose:
PSQA employs gamma analysis to verify the planned versus delivered dose. Evaluating the effectiveness of PSQA techniques in identifying errors is crucial. This study aims to incorporate ML...

Impact of Photon Beam Energy and Symmetry on the Radial Profile Correction Factor for FFF Beams

Authors: Wesley S. Culberson, Larry A. DeWerd, Ahtesham Ullah Khan, Zachary James Welchel

Affiliation: Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin - Madison, University of Wisconsin-Madison

Abstract Preview: Purpose: Flattening filter free (FFF) linac beams exhibit a centrally peaked beam profile due to the forward-directed bremsstrahlung production from MeV electrons, leading to volume averaging effects ...

In-Vivo Dosimetry in Positron-Guided Radiation Therapy

Authors: Davide Brivio, Erno Sajo, Ryan Williams, Piotr Zygmanski

Affiliation: University of Massachusetts Lowell, Brigham and Women's Hospital, Department of Radiation Oncology, Brigham and Women’s Hospital, Dana-Farber Cancer Institute, Harvard Medical School

Abstract Preview: Purpose: To develop a non-invasive 3D in-vivo dosimetry tool exploring the relationship between positron annihilations and dose per voxel using Monte Carlo simulation. The Positron Guided Radiation Th...

Interplay of Relative Biological Effectiveness and Dose Rate in Eye Plaque Brachytherapy with Low Energy Photons

Authors: Alexei V. Chvetsov, Sunan Cui, Sunyoung Jang, Robert D. Stewart

Affiliation: University of Washington and Fred Hutchinson Cancer Center, Penn State College of Medicine, University of Washington

Abstract Preview: Purpose: To evaluate spatial variation of relative biological effectiveness (RBE) in COMS (Collaborative Ocular Melanoma Study) eye plaques with low energy 125I and 103Pd photon sources as a function ...

Investigating the Effect of Beam Flattening Filter on Dose Estimated with Varian’s Original and Enhanced Mlc Models

Authors: Kenny Guida, Hongyu Jiang, Harold Li, Hem Bahadur Moktan Tamang

Affiliation: University of Nebraska Medical Center, Department of Radiation Oncology, University of Kansas Medical Center

Abstract Preview: Purpose: Varian Eclipse v18.0 introduced Enhanced Leaf Model (ELM) of MLC, which provides better dose calculation accuracy than original DLG-based MLC model. The leaf-gap (LG) parameter for ELM repres...

Objective Verification of Mechanical and Radiation Isocenters Independent of Setup

Authors: Jonathan Dowell, Wei Luo, Shane McCarthy, Janelle A. Molloy, Markus Murphy

Affiliation: University of Kentucky, Department of Radiation Medicine, Iridesce Solutions, Inc.

Abstract Preview: Purpose: The novel machine quality assurance (QA) device nĂŒFilm (Iridesce Solutions, Lexington KY) allows for an objective assessment of light and radiation fields independent of setup. Herein, the ab...

Off- Axis Winston Lutz on C-Arm Linac Using in-House Phantom

Authors: Colton Baley, Bhuvaneswari Narayanan, Niko Papanikolaou, Daniel L. Saenz

Affiliation: UT Health San Antonio, Texas Oncology, University of Texas HSC San Antonio

Abstract Preview: Purpose: To evaluate the accuracy of off-axis winston lutz (WLT) for linac based stereotactic radiosurgery (SRS) treatments using in-house phantom.

Methods: Traditional WLT that uses cone and s...

Off-Axis Dependency of the Sun Nuclear MapCheck3 Diode Array

Authors: Alyssa Gadsby, William J. Godwin, Daniel G. McDonald, Jean L. Peng, Alek K. Rapchak, Sean A Roles, Austin M. Skinner, Stephanie Tan

Affiliation: Medical University of South Carolina

Abstract Preview: Purpose: The Sun Nuclear MapCheck3 device is used for patient-specific QA. While it is typically employed in perpendicular field-by-field delivery using the Isocentric Mounting Fixture, fields not ful...

Para-Axial Contouring for Gynecological Brachytherapy or External Radiotherapy in Monaco

Authors: M. Victoria Duran, María Fernåndez, Inés Flores, Joaquin Hernandez, Nuria Montero, Rodrigo Plaza, Manuel Ruiz, Francisco San Miguel, Sandra Williamson Puente, Zigor Zalabarria

Affiliation: Hospital Central de la Defensa 'GĂłmez Ulla', Hospital Central de la Defensa "Gomez Ulla", CSVE, Hospital Central de la Defensa 'GĂłmez Ulla', CSVE

Abstract Preview: Purpose:
Contouring guides recommend using para-axial, para-sagittal and para-coronal axis for delimitation of ROIs. These axis are rotated from the standard axis to match the anatomy of the patien...

Python Scripts for Film-Based PDD and Profile Analyses of HDR Surface Applicators

Authors: Jack Neylon

Affiliation: Department of Radiation Oncology, University of California, Los Angeles

Abstract Preview: Purpose: Commissioning surface applicators is notoriously laborious. In addition, when commissioning Varian surface applicators with vertically positioned source, we found limited data and resources a...

Transformations of the Coordinate System for Monte Carlo Dose Calculations of Spot Scanning Proton Therapy

Authors: Hongyu Jiang

Affiliation: Department of Radiation Oncology, University of Kansas Medical Center

Abstract Preview: Purpose: This study presents a method for transforming coordinates from RayStation’s treatment planning system into the Monte Carlo (MC) coordinate system used in GEANT4 for dose calculations in spot ...

Treatment Machine Matching for ELM in Eclipse v18.0 By Adjusting Physical Leaf Gap

Authors: Quyen Duong, Si Young Jang, Soyoung Lee, Samuel Ming Ho Luk

Affiliation: Boston University, Department of Radiation Oncology, University of Vermont Medical Center, Boston Medical Center

Abstract Preview: Purpose: To investigate the clinical impact of physical MLC gaps changes with Millennium 120 MLC on Enhanced Leaf Modeling (ELM) and patient plans, and to establish a new MLC model in Eclipse v18.0 on...

Validation of SRS Mapcheck for Patient-Specific Quality Assurance of Cyberknife

Authors: Dong Wook Kim, Hojae Kim, Hojin Kim, Jin Sung Kim, Tae Ho Kim, Sangmin Lee

Affiliation: Department of Radiation Oncology, Yonsei Cancer Center, Heavy Ion Therapy Research Institute, Yonsei University College of Medicine

Abstract Preview: Purpose: The CyberKnife system, designed for stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT), considers SRS MapCHECK an effective tool for patient-specific QA (PSQA). This wo...