bluuebunny/crossref_metadata_2025_split huggingface dataset:
WE‐DE‐202‐01: Connecting Nanoscale Physics to Initial DNA Damage Through Track Structure Simulations
Authors: Schuemann J. 
Published: July 2016

Radiation therapy for the treatment of cancer has been established as a highly precise and effective way to eradicate a localized region of diseased tissue. To achieve further significant gains in the therapeutic ratio, we need to move towards biologically optimized treatment planning. To achieve this goal, we need to understand how the radiation‐type dependent patterns of induced energy depositions within the cell (physics) connect via molecular, cellular and tissue reactions to treatment outcome such as tumor control and undesirable effects on normal tissue.Several computational biology approaches have been developed connecting physics to biology. Monte Carlo simulations are the most accurate method to calculate physical dose distributions at the nanometer scale, however simulations at the DNA scale are slow and repair processes are generally not simulated. Alternative models that rely on the random formation of individual DNA lesions within one or two turns of the DNA have been shown to reproduce the clusters of DNA lesions, including single strand breaks (SSBs), double strand breaks (DSBs) without the need for detailed track structure simulations. Efficient computational simulations of initial DNA damage induction facilitate computational modeling of DNA repair and other molecular and cellular processes. Mechanistic, multiscale models provide a useful conceptual framework to test biological hypotheses and help connect fundamental information about track structure and dosimetry at the sub‐cellular level to dose‐response effects on larger scales.In this symposium we will learn about the current state of the art of computational approaches estimating radiation damage at the cellular and sub‐cellular scale. How can understanding the physics interactions at the DNA level be used to predict biological outcome? We will discuss if and how such calculations are relevant to advance our understanding of radiation damage and its repair, or, if the underlying biological processes are too complex for a mechanistic approach. Can computer simulations be used to guide future biological research? We will debate the feasibility of explaining biology from a physicists’ perspective.

Learning Objectives:
Understand the potential applications and limitations of computational methods for dose‐response modeling at the molecular, cellular and tissue levels
Learn about mechanism of action underlying the induction, repair and biological processing of damage to DNA and other constituents
Understand how effects and processes at one biological scale impact on biological processes and outcomes on other scalesJ. Schuemann, NCI/NIH grantsS. McMahon, Funding: European Commission FP7 (grant EC FP7 MC‐IOF‐623630)
WE‐DE‐202‐02: Are Track Structure Simulations Truly Needed for Radiobiology at the Cellular and Tissue Levels?
Authors: Stewart R. 
Published: July 2016

Radiation therapy for the treatment of cancer has been established as a highly precise and effective way to eradicate a localized region of diseased tissue. To achieve further significant gains in the therapeutic ratio, we need to move towards biologically optimized treatment planning. To achieve this goal, we need to understand how the radiation‐type dependent patterns of induced energy depositions within the cell (physics) connect via molecular, cellular and tissue reactions to treatment outcome such as tumor control and undesirable effects on normal tissue.Several computational biology approaches have been developed connecting physics to biology. Monte Carlo simulations are the most accurate method to calculate physical dose distributions at the nanometer scale, however simulations at the DNA scale are slow and repair processes are generally not simulated. Alternative models that rely on the random formation of individual DNA lesions within one or two turns of the DNA have been shown to reproduce the clusters of DNA lesions, including single strand breaks (SSBs), double strand breaks (DSBs) without the need for detailed track structure simulations. Efficient computational simulations of initial DNA damage induction facilitate computational modeling of DNA repair and other molecular and cellular processes. Mechanistic, multiscale models provide a useful conceptual framework to test biological hypotheses and help connect fundamental information about track structure and dosimetry at the sub‐cellular level to dose‐response effects on larger scales.In this symposium we will learn about the current state of the art of computational approaches estimating radiation damage at the cellular and sub‐cellular scale. How can understanding the physics interactions at the DNA level be used to predict biological outcome? We will discuss if and how such calculations are relevant to advance our understanding of radiation damage and its repair, or, if the underlying biological processes are too complex for a mechanistic approach. Can computer simulations be used to guide future biological research? We will debate the feasibility of explaining biology from a physicists’ perspective.

Learning Objectives:
Understand the potential applications and limitations of computational methods for dose‐response modeling at the molecular, cellular and tissue levels
Learn about mechanism of action underlying the induction, repair and biological processing of damage to DNA and other constituents
Understand how effects and processes at one biological scale impact on biological processes and outcomes on other scalesJ. Schuemann, NCI/NIH grantsS. McMahon, Funding: European Commission FP7 (grant EC FP7 MC‐IOF‐623630)
WE‐DE‐209‐05: Self‐Held Breath Control with Respiratory Monitoring and Feedback Guidance
Authors: Gifford K. 
Published: July 2016

Breast radiation therapy is associated with some risk of lung toxicity as well as cardiac toxicity for left‐sided cases. Radiation doses to the lung and heart can be reduced by using the deep inspiration breath hold (DIBH) technique, in which the patient is simulated and treated during the deep inspiration phase of the breathing cycle. During DIBH, the heart is usually displaced posteriorly, inferiorly, and to the right, effectively expanding the distance between the heart and the breast/chest wall. As a result, the distance between the medial treatment field border and heart/lung is increased. Also, in a majority of DIBH patients, the air drawn into the thoracic cavity increases the total lung volume.The DIBH was discussed by an AAPM Task Group 10 years ago in the AAPM TG 76 report. However, DIBH is still not the standard of care in many clinics, which may be partially due to challenges associated with its implementation. Therefore, this seccion will focus primarily on how to clinically implement four different DIBH techniques: (1) Active Breathing Control, (2) Spirometric Motion Management, (3) 3D Surface Image‐Guided, and (4) Self‐held Breath Control with Respiratory Monitoring and Feedback Guidance.

Learning Objectives:
Describe the physical displacement of the heart and the change in lung volume during DIBH and discuss dosimetric consequences of those changes.
Provide an overview of the technical aspects.
Describe work flow for patient simulation and treatment.
Give an overview of commissioning and routine.
Provide practical tips for clinical implementation.
WE‐DE‐206‐02: MRI Hardware ‐ Magnet, Gradient, RF Coils
Authors: Kocharian A. 
Published: July 2016

Magnetic resonance imaging (MRI) has become an essential part of clinical imaging due to its ability to render high soft tissue contrast. Instead of ionizing radiation, MRI use strong magnetic field, radio frequency waves and field gradients to create diagnostic useful images. It can be used to image the anatomy and also functional and physiological activities within the human body. Knowledge of the basic physical principles underlying MRI acquisition is vitally important to successful image production and proper image interpretation.This lecture will give an overview of the spin physics, imaging principle of MRI, the hardware of the MRI scanner, and various pulse sequences and their applications. It aims to provide a conceptual foundation to understand the image formation process of a clinical MRI scanner.

Learning Objectives:
Understand the origin of the MR signal and contrast from the spin physics level.
Understand the main hardware components of a MRI scanner and their purposes
Understand steps for MR image formation including spatial encoding and image reconstruction
Understand the main kinds of MR pulse sequences and their characteristics.
WE‐DE‐209‐00: Practical Implementation of Deep Inspiration Breath Hold Techniques for Breast Radiation Therapy
Authors: Howell Rebecca 
Published: July 2016

Breast radiation therapy is associated with some risk of lung toxicity as well as cardiac toxicity for left‐sided cases. Radiation doses to the lung and heart can be reduced by using the deep inspiration breath hold (DIBH) technique, in which the patient is simulated and treated during the deep inspiration phase of the breathing cycle. During DIBH, the heart is usually displaced posteriorly, inferiorly, and to the right, effectively expanding the distance between the heart and the breast/chest wall. As a result, the distance between the medial treatment field border and heart/lung is increased. Also, in a majority of DIBH patients, the air drawn into the thoracic cavity increases the total lung volume.The DIBH was discussed by an AAPM Task Group 10 years ago in the AAPM TG 76 report. However, DIBH is still not the standard of care in many clinics, which may be partially due to challenges associated with its implementation. Therefore, this seccion will focus primarily on how to clinically implement four different DIBH techniques: (1) Active Breathing Control, (2) Spirometric Motion Management, (3) 3D Surface Image‐Guided, and (4) Self‐held Breath Control with Respiratory Monitoring and Feedback Guidance.

Learning Objectives:
Describe the physical displacement of the heart and the change in lung volume during DIBH and discuss dosimetric consequences of those changes.
Provide an overview of the technical aspects.
Describe work flow for patient simulation and treatment.
Give an overview of commissioning and routine.
Provide practical tips for clinical implementation.
WE‐DE‐209‐01: Dosimetric Benefits of DIBH
Authors: Howell R. 
Published: July 2016

Breast radiation therapy is associated with some risk of lung toxicity as well as cardiac toxicity for left‐sided cases. Radiation doses to the lung and heart can be reduced by using the deep inspiration breath hold (DIBH) technique, in which the patient is simulated and treated during the deep inspiration phase of the breathing cycle. During DIBH, the heart is usually displaced posteriorly, inferiorly, and to the right, effectively expanding the distance between the heart and the breast/chest wall. As a result, the distance between the medial treatment field border and heart/lung is increased. Also, in a majority of DIBH patients, the air drawn into the thoracic cavity increases the total lung volume.The DIBH was discussed by an AAPM Task Group 10 years ago in the AAPM TG 76 report. However, DIBH is still not the standard of care in many clinics, which may be partially due to challenges associated with its implementation. Therefore, this seccion will focus primarily on how to clinically implement four different DIBH techniques: (1) Active Breathing Control, (2) Spirometric Motion Management, (3) 3D Surface Image‐Guided, and (4) Self‐held Breath Control with Respiratory Monitoring and Feedback Guidance.

Learning Objectives:
Describe the physical displacement of the heart and the change in lung volume during DIBH and discuss dosimetric consequences of those changes.
Provide an overview of the technical aspects.
Describe work flow for patient simulation and treatment.
Give an overview of commissioning and routine.
Provide practical tips for clinical implementation.
WE‐DE‐209‐02: Active Breathing Control
Authors: Comsa D. 
Published: July 2016

Breast radiation therapy is associated with some risk of lung toxicity as well as cardiac toxicity for left‐sided cases. Radiation doses to the lung and heart can be reduced by using the deep inspiration breath hold (DIBH) technique, in which the patient is simulated and treated during the deep inspiration phase of the breathing cycle. During DIBH, the heart is usually displaced posteriorly, inferiorly, and to the right, effectively expanding the distance between the heart and the breast/chest wall. As a result, the distance between the medial treatment field border and heart/lung is increased. Also, in a majority of DIBH patients, the air drawn into the thoracic cavity increases the total lung volume.The DIBH was discussed by an AAPM Task Group 10 years ago in the AAPM TG 76 report. However, DIBH is still not the standard of care in many clinics, which may be partially due to challenges associated with its implementation. Therefore, this seccion will focus primarily on how to clinically implement four different DIBH techniques: (1) Active Breathing Control, (2) Spirometric Motion Management, (3) 3D Surface Image‐Guided, and (4) Self‐held Breath Control with Respiratory Monitoring and Feedback Guidance.

Learning Objectives:
Describe the physical displacement of the heart and the change in lung volume during DIBH and discuss dosimetric consequences of those changes.
Provide an overview of the technical aspects.
Describe work flow for patient simulation and treatment.
Give an overview of commissioning and routine.
Provide practical tips for clinical implementation.
WE‐DE‐207B‐06: Artifact Reduction in Digital Breast Tomosynthesis with the Denoised Ordered‐Subset Statistically Penalized Algebraic Reconstruction Technique (DOS‐SPART) Algorithm
Authors: Garrett J , Li Y , Li K , Chen G 
Published: July 2016

Purpose:Digital breast tomosynthesis (DBT) is an emerging breast imaging modality. It uses x‐ray absorption projection images acquired over a narrow angular span to provide high spatial resolution pseudo‐three dimensional images for breast cancer screening and diagnosis. Unfortunately, the narrow range used to acquire data (typically <30 degrees) results in significant out of plane artifacts for high contrast objects when conventional reconstruction techniques are used. In this work, the denoised ordered‐subset statistically penalized algebraic reconstruction technique (DOS‐SPART) algorithm was adapted to breast tomosynthesis imaging to reduce out‐of‐plane blurring artifacts.Methods:The DOS‐SPART algorithm was implemented for use with DBT datasets. The ACR mammography accreditation phantom was imaged for quantitative measurement and subjective image analysis. The artifact spread function (ASF) was measured for images generated by the commercial reconstruction method as well as DOS‐SPART with different total number of iterations (5, 10, 15, and 20). The FWHM of the ASF was used to quantify out‐of‐plane blurring. A cluster of calcifications in the ACR phantom was also inspected subjectively, and images above and below the feature were examined for artifacts.Results:The DOS‐SPART algorithm was able to efficiently reconstruct sharp image at the in‐focus plane, while significantly reducing out‐of‐plane blurring artifacts (total reconstruction time <90 seconds for a 1996×2457×70 voxel volume with 5 iterations). The FWHM of the ASF was reduced by as much as 35% using the algorithm. Subjectively, the out‐of‐plane artifacts from the high contrast calcification are still clearly visible in the commercial reconstruction at 1 cm above or below the in‐focus plane, whereas no artifacts from the calcification are detectable in the out‐of‐plane images generated with DOS‐SPART.Conclusion:The application of DOS‐SPART to DBT can help limit out‐of‐plane artifacts in DBT imaging, potentially improving localization of microcalcifications and image contrast for adjacent structures.Funding support: This work was support in part by NIH R01 EB020521. Disclosures: J Garrett: None. Y. Li: None. K. Li: None. GH Chen: Research funded, GE Healthcare and Siemens AX
WE‐DE‐207B‐07: Hotelling Templates Without Additional Training Data for Breast Tomosynthesis Observer Models
Authors: Zeng R , Badano A 
Published: July 2016

Purpose:To describe and test a practical approach that uses minimal training data for estimating signal mean and background statistics to compute the Hotelling observer (HO) in digital breast tomosynthesis (DBT).Methods:Best among all linear observers, Hotelling observer (HO) is desired for many detection tasks. However, training data cost is usually high for obtaining prior information regarding the signal and data covariance. This limits the HO's utility in many practical situations. We propose that, in breast tomosynthesis images, it is feasible to estimate priors without using additional training data. The approach consists of obtaining the signal mean from a subtraction of noiseless reconstructions of a uniform background with and without signal and the noise power spectrum (NPS) computed from each breast tomosynthesis image itself, and implementing the HO in the Fourier domain. We call this approach no‐additional‐training Fourier HO (FHO). We compare this approach to the usual‐training approach with pre‐acquired training data to examine whether the resulting performances are comparable. We utilize a baseline model observer (MO) without prewhitening and an efficient MO with Laguerre‐Gauss channelized HO (LG‐CHO) to examine the efficiency of the no‐additional‐training FHO. Performance is evaluated in terms of lesion detectability using simulated DBT images corresponding to the UPENN breast phantoms with spherical lesions and two types of reconstruction.Results:The no‐additional‐training FHO yielded similar and even higher performance compared to the usual‐training approach in all the simulated imaging conditions. The performance improvement over non‐prewhitening MO was substantial and over LG‐CHO was also moderate, indicating a higher efficiency of the no‐additional‐training FHO in detecting lesions from the simulated DBT images.Conclusion:The approach to estimate HO templates without additional training data shows excellent performance with simulated breast tomosynthesis data. Its efficiency will be further tested on virtual and real patient breast tomosynthesis image sets.
WE‐DE‐207B‐09: Scatter Radiation Measurement From a Digital Breast Tomosynthesis System and Its Impact On Shielding Consideration
Authors: Yang K , Li X , Liu B 
Published: July 2016

Purpose:To accurately measure the scatter radiation from a Hologic digital breast tomosynthesis (DBT) system and to provide updated scatter distribution to guide radiation shielding calculation for DBT rooms.Methods:A high sensitivity GOS‐based linear detector was used to measure the angular distribution of scatter radiation from a Hologic Selenia Dimensions DBT system. The linear detector was calibrated for its energy response of typical DBT spectra. Following the NCRP147 approach, the measured scatter intensity was normalized by the primary beam area and primary air kerma at 1m from the scatter phantom center and presented as the scatter fraction. Direct comparison was made against Simpkin's initial measurement. Key parameters including the phantom size, primary beam area, and kV/anode/target combination were also studied.Results:The measured scatter‐to‐primary‐ratio and scatter fraction data closely matched with previous data from Simpkin. The measured data demonstrated the unique nonisotropic distribution of the scattered radiation around a Hologic DBT system, with two strong peaks around 25° and 160°. The majority scatter radiation (>70%) originated from the imaging detector assembly, instead of the phantom. With a workload from a previous local survey, the scatter air kerma at 1m from the phantom center for wall/door is 0.018mGy/patient, for floor is 0.164mGy/patient, and for ceiling is 0.037mGy/patient.Conclusion:Comparing to Simpkin's previous data, the scatter air kerma from Holgoic DBT is at least two times higher. The main reasons include the harder primary beam with higher workload, added tomosynthesis acquisition, and strong small angle forward scattering. Due to the highly conservative initial assumptions, the shielding recommendation from NCRP147 is still sufficient for the Hologic DBT system given the workload from a previous local survey. With the data provided from this study, accurate shielding calculation can be performed for Hologic DBT systems with specific workload and barrier distance.
WE‐C‐TOUR‐I‐01: Dosimters for QC in Diagnostic Imaging
Authors: Jiang X. 
Published: July 2016

Tour Leader: Xia Jiang, Ohio State University, Columbus, OHTour Guides:Xia Jiang, Ohio State University, Columbus, OHKevin Little, The University of Chicago, Chicago, ILAdrien Sanchez, University of Chicago, Chicago, ILParticipating Vendors:IBAPTW ‐ New YorkRadcal CorporationRTI Electronics, Inc.Exhibit Hall Guided Tours is a new program launching this year at the Annual Meeting. The Guided Tours are designed to enhance the interaction between meeting attendees and exhibitors. This year's Imaging Guided Tours are organized around the theme of dosimeters for quality control in diagnostic imaging. Tours will begin with an introduction and background given by Dr. Xia Jiang, the Tour Leader. The introduction will cover the types and properties of different radiation dosimeters used for quality assurance in clinical radiology. Attendees will then break into smaller groups, each lead by an AAPM‐member Tour Guide. The tour groups will visit the exhibit booths of vendors who provide appropriate dosimeters, and a vendor representative will give a presentation to the group about their particular product(s). The vendor representatives as well as the Tour Guides will be available to answer questions.Outline:
Types and properties of radiation detectors and dosimeters
Ionization chamber dosimeters
Solid state dosimeters
Dosimeter calibration: Primary and secondary standards dosimetry laboratories
Instruments for measuring tube voltage and exposure timeVendor presentations will likely cover features and innovations of different dosimeter systems, as well as their practical use.

Learning Objectives:
Understand the types and properties of different instrumentations used for quality control in diagnostic imaging.
Understand the process of dosimeter calibration.
Gain familiarity with the latest commercial dosimeter systems from different vendors.