bluuebunny/crossref_metadata_2025_split huggingface dataset:
TU‐G‐204‐09: The Effects of Reduced‐ Dose Lung Cancer Screening CT On Lung Nodule Detection Using a CAD Algorithm
Authors: Young S , Lo P , Kim G , Hsu W , Hoffman J , Brown M , McNitt‐Gray M 
Published: June 2015

Purpose:While Lung Cancer Screening CT is being performed at low doses, the purpose of this study was to investigate the effects of further reducing dose on the performance of a CAD nodule‐detection algorithm.Methods:We selected 50 cases from our local database of National Lung Screening Trial (NLST) patients for which we had both the image series and the raw CT data from the original scans. All scans were acquired with fixed mAs (25 for standard‐sized patients, 40 for large patients) on a 64‐slice scanner (Sensation 64, Siemens Healthcare). All images were reconstructed with 1‐mm slice thickness, B50 kernel. 10 of the cases had at least one nodule reported on the NLST reader forms. Based on a previously‐published technique, we added noise to the raw data to simulate reduced‐dose versions of each case at 50% and 25% of the original NLST dose (i.e. approximately 1.0 and 0.5 mGy CTDIvol). For each case at each dose level, the CAD detection algorithm was run and nodules greater than 4 mm in diameter were reported. These CAD results were compared to “truth”, defined as the approximate nodule centroids from the NLST reports. Subject‐level mean sensitivities and false‐positive rates were calculated for each dose level.Results:The mean sensitivities of the CAD algorithm were 35% at the original dose, 20% at 50% dose, and 42.5% at 25% dose. The false‐positive rates, in decreasing‐dose order, were 3.7, 2.9, and 10 per case. In certain cases, particularly in larger patients, there were severe photon‐starvation artifacts, especially in the apical region due to the high‐attenuating shoulders.Conclusion:The detection task was challenging for the CAD algorithm at all dose levels, including the original NLST dose. However, the false‐positive rate at 25% dose approximately tripled, suggesting a loss of CAD robustness somewhere between 0.5 and 1.0 mGy.NCI grant U01 CA181156 (Quantitative Imaging Network); Tobacco Related Disease Research Project grant 22RT‐0131.
TU‐G‐207‐00: Emerging Applications of X‐Ray Imaging
Authors: Xing Lei 
Published: June 2015

Last few years has witnessed the development of novel of X‐ray imaging modalities, such as spectral CT, phase contrast CT, and X‐ray acoustic/fluorescence/luminescence imaging. This symposium will present the recent advances of these emerging X‐ray imaging modalities and update the attendees with knowledge in various related topics, including X‐ray photon‐counting detectors, X‐ray physics underlying the emerging applications beyond the traditional X‐ray imaging, image reconstruction for the novel modalities, characterization and evaluation of the systems, and their practical implications. In addition, the concept and practical aspects of X‐ray activatable targeted nanoparticles for molecular X‐ray imaging will be discussed in the context of X‐ray fluorescence and luminescence CT.Learning Objectives:

Present background knowledge of various emerging X‐ray imaging techniques, such as spectral CT, phase contrast CT and X‐ray fluorescence/luminescence CT.
Discuss the practical need, technical aspects and current status of the emerging X‐ray imaging modalities.
Describe utility and future impact of the new generation of X‐ray imaging applications.
TU‐G‐207‐01: CT Imaging Using Energy‐Sensitive Photon‐Counting Detectors
Authors: Taguchi K. 
Published: June 2015

Last few years has witnessed the development of novel of X‐ray imaging modalities, such as spectral CT, phase contrast CT, and X‐ray acoustic/fluorescence/luminescence imaging. This symposium will present the recent advances of these emerging X‐ray imaging modalities and update the attendees with knowledge in various related topics, including X‐ray photon‐counting detectors, X‐ray physics underlying the emerging applications beyond the traditional X‐ray imaging, image reconstruction for the novel modalities, characterization and evaluation of the systems, and their practical implications. In addition, the concept and practical aspects of X‐ray activatable targeted nanoparticles for molecular X‐ray imaging will be discussed in the context of X‐ray fluorescence and luminescence CT.Learning Objectives:

Present background knowledge of various emerging X‐ray imaging techniques, such as spectral CT, phase contrast CT and X‐ray fluorescence/luminescence CT.
Discuss the practical need, technical aspects and current status of the emerging X‐ray imaging modalities.
Describe utility and future impact of the new generation of X‐ray imaging applications.
TU‐G‐201‐03: Imaging Systems in Radiotherapy: Buying, Installing, and Using
Authors: Hunt M. 
Published: June 2015

This session will update therapeutic physicists on technological advancements and radiation oncology features of commercial CT, MRI, and PET/CT imaging systems. Also described are physicists’ roles in every stage of equipment selection, purchasing, and operation, including defining specifications, evaluating vendors, making recommendations, and optimal and safe use of imaging equipment in radiation oncology environment.The first presentation defines important terminology of CT and PET/CT followed by a review of latest innovations, such as metal artifact reduction, statistical iterative reconstruction, radiation dose management, tissue classification by dual energy CT and spectral CT, improvement in spatial resolution and sensitivity in PET, and potentials of PET/MR. We will also discuss important technical specifications and items in CT and PET/CT purchasing quotes and their impacts.The second presentation will focus on key components in the request for proposal for a MRI simulator and how to evaluate vendor proposals. MRI safety issues in radiation Oncology, including MRI scanner Zones (4‐zone design), will be discussed. Basic MR terminologies, important functionalities, and advanced features, which are relevant to radiation therapy, will be discussed.In the third presentation, justification of imaging systems for radiation oncology, considerations in room design and construction in a RO department, shared use with diagnostic radiology, staffing needs and training, clinical/research use cases and implementation, will be discussed. The emphasis will be on understanding and bridging the differences between diagnostic and radiation oncology installations, building consensus amongst stakeholders for purchase and use, and integrating imaging technologies into the radiation oncology environment.Learning Objectives:

Learn the latest innovations of major imaging systems relevant to radiation therapy
Be able to describe important technical specifications of CT, MRI, and PET/CT
Understand the process of budget request, equipment justification, comparisons of technical specifications, site visits, vendor selection, and contract development
TU‐F‐CAMPUS‐T‐05: Replacement Computational Phantoms to Estimate Dose in Out‐Of‐Field Organs and Tissues
Authors: Gallagher K , Tannous J , Nabha R , Feghali J , Ayoub Z , Jalbout W , Youssef B , Taddei P 
Published: June 2015

Purpose:To estimate the absorbed dose in organs and tissues at risk for radiogenic cancer for children receiving photon radiotherapy for localized brain tumors (LBTs) by supplementing their missing body anatomies with those of replacement computational phantoms. Applied beyond the extent of the RT Images collected by computed tomography simulation, these phantoms included RT Image and RT Structure Set objects that encompassed sufficient extents and contours for dosimetric calculations.Method:Nine children, aged 2 to 14 years, who received three‐dimensional conformal radiotherapy for low‐grade LBTs, were randomly selected for this study under Institutional‐Review‐Board protocol. Because the extents of their RT Images were cranial only, they were matched for size and sex with patients from a previous study with larger extents and for whom contours of organs at risk for radiogenic cancer had already been delineated. Rigid fusion was performed between the patients’ data and those of the replacement computational phantoms using commercial software. In‐field dose was calculated with a clinically‐commissioned treatment planning system, and out‐of‐field dose was estimated with an analytical model.Results:Averaged over all nine children and normalized for a therapeutic dose of 54 Gy prescribed to the PTV, where the PTV is the GTV, the highest mean organ doses were 3.27, 2.41, 1.07, 1.02, 0.24, and 0.24 Gy in the non‐tumor remainder, red bone marrow, thyroid, skin, breasts, and lungs, respectively. The mean organ doses ranged by a factor of 3 between the smallest and largest children.Conclusion:For children receiving photon radiotherapy for LBTs, we found their doses in organs at risk for second cancer to be non‐negligible, especially in the non‐tumor remainder, red bone marrow, thyroid, skin, breasts, and lungs. This study demonstrated the feasibility for patient dosimetry studies to augment missing patient anatomy by applying size‐ and sex‐matched replacement computational phantoms with pre‐contoured organs.Funding is in part by the Fogarty International Center award K01TW008409, and the Portland Chapter of the Achievement Rewards for College Scientists. The content is solely the responsibility of the authors, and does not necessarily represent the official views of the sponsors. The authors declare no conflict of interest.
TU‐F‐CAMPUS‐J‐04: Setup Uncertainties in the Mediastinum Area for IMRT Treatment of Lymphoma Patients
Authors: Aristophanous M , Court L 
Published: June 2015

Purpose:Despite daily image guidance setup uncertainties can be high when treating large areas of the body. The aim of this study was to measure local uncertainties inside the PTV for patients receiving IMRT to the mediastinum region.Methods:Eleven lymphoma patients that received radiotherapy (breath‐hold) to the mediastinum were included in this study. The treated region could range all the way from the neck to the diaphragm. Each patient had a CT scan with a CT‐on‐rails system prior to every treatment. The entire PTV region was matched to the planning CT using automatic rigid registration. The PTV was then split into 5 regions: neck, supraclavicular, superior mediastinum, upper heart, lower heart. Additional auto‐registrations for each of the 5 local PTV regions were performed. The residual local setup errors were calculated as the difference between the final global PTV position and the individual final local PTV positions for the AP, SI and RL directions. For each patient 4 CT scans were analyzed (1 per week of treatment).Results:The residual mean group error (M) and standard deviation of the inter‐patient (or systematic) error (Σ) were lowest in the RL direction of the superior mediastinum (0.0mm and 0.5mm) and highest in the RL direction of the lower heart (3.5mm and 2.9mm). The standard deviation of the inter‐fraction (or random) error (σ) was lowest in the RL direction of the superior mediastinum (0.5mm) and highest in the SI direction of the lower heart (3.9mm) The directionality of local uncertainties is important; a superior residual error in the lower heart for example keeps it in the global PTV.Conclusion:There is a complex relationship between breath‐holding and positioning uncertainties that needs further investigation. Residual setup uncertainties can be significant even under daily CT image guidance when treating large regions of the body.
TU‐F‐CAMPUS‐J‐05: Fast Volumetric MRI On An MRI‐Linac Enables On‐Line QA On Dose Deposition in the Patient
Authors: Crijns S , Glitzner M , de Senneville B Denis , Kontaxis C , Maenhout M , Bol G , Lagendijk J , Raaymakers B 
Published: June 2015

Purpose:The introduction of the MRI‐linac in radiotherapy brings MRI‐guided treatment with daily plan adaptions within reach. This paradigm demands on‐line QA. With its ability to perform continuous volumetric imaging in an outstanding soft‐tissue contrast, the MRI‐ linac promises to elucidate the dose deposition process during a treatment session. Here we study for a prostate case how dynamic MRI combined with linac machine parameters and a fast dose‐engine can be used for on‐line dose accumulation.Methods:Prostate imaging was performed in healthy volunteer on a 1.5T MR‐scanner (Philips, Best, NL) according to a clinical MR‐sim protocol, followed by 10min of dynamic imaging (FLASH, 4s/volume, FOV 40×40×12cm3, voxels 3×3×3mm3, TR/TE/α=3.5ms/1.7ms/5°). An experienced radiation oncologist made delineations, considering the prostate CTV. Planning was performed on a two‐compartment pseudoCT (air/water density) according to clinical constraints (77Gy in PTV) using a Monte‐Carlo (MC) based TPS that accounts for magnetic fields. Delivery of one fraction (2.2Gy) was simulated on an emulator for the Axesse linac (Elekta, Stockholm, SE). Machine parameters (MLC settings, gantry angle, dose rate, etc.) were recorded at 25Hz. These were re‐grouped per dynamic volume and fed into the MC‐engine to calculate a dose delivered for each of the dynamics. Deformations derived from non‐rigid registration of each dynamic against the first allowed dose accumulation on a common reference grid.Results:The DVH parameters on the PTV compared to the optimized plan showed little changes. Local deformations however resulted in local deviations, primarily around the air/rectum interface. This clearly indicates the potential of intra‐fraction adaptations based on the accumulated dose. Application in each fraction helps to track the influence of plan adaptations to the eventual dose distribution. Calculation times were about twice the delivery time.Conclusion:The current Result paves the way to perform on‐line treatment delivery QA on the MRI‐linac in the near future.
WE‐E‐304‐01: SBRT Credentialing: Understanding the Process From Inquiry to Approval
Authors: Followill D. 
Published: June 2015

SBRT is having a dramatic impact on radiation therapy of early‐stage, locally advanced cancers. A number of national protocols have been and are being developed to assess the clinical efficacy of SBRT for various anatomical sites, such as lung and spine. Physics credentialing for participating and implementation of trial protocols involve a broad spectrum of requirements from image guidance, motion management, to planning technology and dosimetric constrains. For radiation facilities that do not have extensive experiences in SBRT treatment and protocol credentialing, these complex processes of credentialing and implementation could be very challenging and, sometimes, may lead to ineffective even unsuccessful execution of these processes. In this proposal, we will provide comprehensive review of some current SBRT protocols, explain the requirements and their underline rationales, illustrate representative failed and successful experiences, related to SBRT credentialing, and discuss strategies for effective SBRT credentialing and implementation.Learning Objectives:

Understand requirements and challenges of SBRT credentailing and implentation
Discuss processes and strategies of effective SBRT credentailing
Discuss practical considerations, potential pitfalls and solutions of SBRT implentation
WE‐E‐BRB‐01: Clinical Usage of Knowledge Based Treatment Planning
Authors: Zhang X. 
Published: June 2015

The knowledge‐based treatment planning automation has evolved from academic research from the clinical application with the involvement of the major industry TPS vendors. Previous work proved the concept that IMRT or VMAT plans can be designed without or with minimal human intervention. Recently, the major industry vendors start releasing the automatic planning product such as Philips automatic treatment planning, Varian's Rapidplan, and RaySearch's autoplan. Many centers start to evaluate and use the automatic planning products from TPS vendors. It is more and more becoming evident that automatic planning will be routinely used in the clinic.The first presentation will focus on the knowledge modeling for clinical treatment planning. The presenter will introduce the algorithm and theory for developing the dose volume histogram (DVH) model, summarize the results on the validation of the DVH model, and discuss the application of DVH for the automatic treatment planning. The second presenter will focus on the clinical use of the automatic treatment planning. The presenter will give an overview of the several automatic treatment planning tools including the tools developed commercially and in‐house, present the early experience of using those tools, and discuss the application of the tools in the routine clinical use and in the quality control of the treatment planning.Learning Objectives:

Describe the algorithm and theory behind the knowledge based treatment planning automation.
Clinical experience of using automatic planning in clinical trial and patient treatment
Early clinical experience of using commercial automatic planning approach
The application of automatic planning approach to perform quality assurance of treatment plan.
XD obtain the research funding from Varian Medical System, Philips Medical System and Funding support form Sister Institution Network Fund of MD Anderson, XD is also a founder of Global Oncology One
WE‐EF‐BRA‐08: Cell Survival in Modulated Radiation Fields and Altered DNA‐Repair at Field Edges
Authors: Bartzsch S , Eismann S , Oelfke U 
Published: June 2015

Purpose:Tissue damage prognoses in radiotherapy are based on clonogenic assays that provide dose dependent cell survival rates. However, recent work has shown that apart from dose, systemic reactions and cell‐cell communication crucially influence the radiation response. These effects are probably a key in understanding treatment approaches such as microbeam radiation therapy (MRT). In this study we tried to quantify the effects on a cellular level in spatially modulated radiation fields.Methods:Pancreas carcinoma cells were cultured, plated and irradiated by spatially modulated radiation fields with an X‐ray tube and at a synchrotron. During and after treatment cells were able to communicate via the intercellular medium. Afterwards we stained for DNA and DNA damage and imaged with a fluorescence microscope.Results:Intriguingly we found that DNA damage does not strictly increase with dose. Two cell entities appear that have either a high or a low amount of DNA lesions, indicating that DNA damage is also a cell stress reaction. Close to radiation boundaries damage‐levels became alike; they were higher than expected at low and lower than expected at high doses. Neighbouring cells reacted similarly. 6 hours after exposure around 40% of the cells resembled in their reactions neighbouring cells more than randomly chosen cells that received the same dose. We also observed that close to radiation boundaries the radiation induced cell‐cycle arrest disappeared and the size of DNA repair‐centres increased.Conclusion:Cell communication plays an important role in the radiation response of tissues and may be both, protective and destructive. These effects may not only have the potential to affect conventional radiotherapy but may also be exploited to spare organs at risk by intelligently designing irradiation geometries. To that end intensive work is required to shed light on the still obscure processes in cell‐signalling and radiation biology.
WE‐EF‐BRA‐10: Prophylactic Cranial Irradiation Reduces the Incidence of Brain Metastasis in a Mouse Model of Metastatic Breast Cancerr
Authors: Smith D , Debeb B , Larson R , Diagaradjane P , Woodward W 
Published: June 2015

Purpose:Prophylactic cranial irradiation (PCI) is a clinical technique used to reduce the incidence of brain metastasis and improve overall survival in select patients with acute lymphoblastic leukemia and small‐cell lung cancer. We examined whether PCI could benefit breast cancer patients at high risk of developing brain metastases.Methods:We utilized our mouse model in which 500k green fluorescent protein (GFP)‐labeled breast cancer cells injected into the tail vein of SCID/Beige mice resulted in brain metastases in approximately two‐thirds of untreated mice. To test the efficacy of PCI, one set of mice was irradiated five days after cell injection with a single fraction of 4‐Gy (two 2‐Gy opposing fields) whole‐brain irradiation on the XRAD 225Cx small‐animal irradiator. Four controls were included: a non‐irradiated group, a group irradiated two days prior to cell injection, and two groups irradiated 3 or 6 weeks after cell injection. Mice were sacrificed four and eight weeks post‐injection and were evaluated for the presence of brain metastases on a fluorescent stereomicroscope.Results:The incidence of brain metastasis in the non‐irradiated group was 77% and 90% at four and eight weeks, respectively. The PCI group had a significantly lower incidence, 20% and 30%, whereas the other three control groups had incidence rates similar to the non‐treated control (70% to 100%). Further, the number of metastases and the metastatic burden were also significantly lower in the PCI group compared to all other groups.Conclusion:The timing of irradiation to treat subclinical disease is critical, as a small dose of whole‐brain irradiation given five days after cell injection abrogated tumor burden by greater than 90%, but had no effect when administered twenty‐one days after cell injection. PCI is likely to benefit breast cancer patients at high risk of developing brain metastases and should be strongly considered in the clinic.
WE‐EF‐BRA‐11: Precision Partial‐Tumor Irradiation of Dorsal Rodent Mammary Tumors
Authors: Malcolm J , Boss K , Dewhirst M , Oldham M 
Published: June 2015

Purpose:To introduce a pre‐clinical treatment technique on a micro‐irradiator to treat specific volumes of dorsal mammary tumors in BALB/c mice while sparing lungs and spine. This technique facilitates pre‐clinical investigation of tumor response to sub‐optimal radiation treatments in which a portion of the tumor is unirradiated, known as a “marginal miss”. In‐vitro data suggests that partial tumor radiations trigger a more aggressive phenotype in non‐irradiated, regional tumor cells via bystander effects. As the lung tissue is spared, the impact of marginal miss on the development of pulmonary metastasis may be assessed.Methods:End to end test was performed on three BALB/c mice as proof of concept for larger studies. 1Gy was delivered on the micro‐irradiator employing previously unexplored lateral parallel‐opposed diamond and/or triangle‐shaped beams. The margins of the treatment beam were defined using a combination of tumor palpation, barium fiducial markers, and real‐time fluoroscopic images. The dose distribution was independently verified with kilovoltage beam Monte Carlo dose calculations with 7% statistical uncertainty and double exposure images. As a final step, the technique was used in a larger pre‐clinical study (15Gy, 36 BALB/c mice) and lung metastasis in response to tumor irradiation of 100%, 50% and 0% was quantified.Results:For the Monte‐Carlo dose calculations, the dose volume histograms established a maximum dose within the un‐irradiated and radiated portions of the mammary tumor of 0.3Gy and 1.5Gy respectively, with a sharp gradient at the boundary. 100% of the lung volume received less than 0.5Gy. This technique proved suitable for a pre‐clinical marginal miss study with 50% more lung metastases in partially‐radiated mouse models compared to completely.Conclusion:We have developed a novel treatment technique for partial or full irradiation of dorsal mammary tumors incorporating lung sparing.The technique will be useful for exploring the phenomena of aggressive tumor phenotype that may arise from miss‐irradiation.