bluuebunny/crossref_metadata_2025_split huggingface dataset:
TH‐B‐211‐02: Patient Organ Doses From Imaging in IGRT: KV Radiograph Vs. KV‐ CBCT Vs. MV Portal Image Vs. MV‐CBCT
Authors: Ding G , Alaei P 
Published: June 2012

Image‐guided radiation therapy (IGRT) plays an increasingly essential role in the accurate delivery of highly conformal dose to the target as it makes it possible to see the target and organs at risk before treatment while the patient is in the treatment position. X‐ray imaging devices, especially kilovoltage x‐ray imaging devices integrated in a radiation treatment delivery unit, are increasingly available in the clinics. The conventional electronic portal imaging devices (EPID) using megavoltage photon beams are still available and being used as well. X‐ray imaging procedures deliver additional radiation dose to patients and this dose may entail risk to patients. Knowledge of radiation dose resulting from x‐ray imaging and the techniques to reduce the imaging dose are important for clinicians in making informed decisions for treatment management regarding the benefit and risk to patients. This lecture will provide an overview of radiation doses to patients resulting from different imaging procedures and an update on the progress of AAPM TG‐180 report.Learning Objectives:1. Understand the different available image guidance modalities and devices used in IGRT;2. Understand the magnitude of the organ dose resulting from difference devices and acquisition procedures;3. Understand the variation of patient imaging dose distributions among different imaging procedures;4. Understand how patient dose distributions from an image procedure are calculated5. Understand the increased magnitude of the dose to bone as compared to soft tissue for kilovoltage x‐rays;6. Learn the techniques to reduce the imaging dose to patients and sensitive organs;7. Update on the progress of AAPM TG‐180 report: “Modeling and Accounting for the Imaging Guidance Radiation Doses to Radiotherapy Patients in Treatment Planning”
TH‐C‐BRCD‐01: Small Field Dosimetry: A Clinical Perspective
Authors: Das I 
Published: June 2012

Small fields on the order of few millimeters are now being used in specialized radiation treatments such as intensity modulated radiation therapy (IMRT), stereotactic radiosurgery (SRS), cyber‐knife and gamma‐knife. Small‐field dosimetry is challenging due to finite source size, lack of electronic equilibrium, size of detectors, changes in energy spectrum with associated dosimetric parameters and stopping power ratio. Source size is dependent on the design of the accelerator and could be obstructed by the collimating system with decreasing field sizes. Electronic equilibrium is a phenomenon associated with the range of secondary particles and hence dependent on the beam energy, spectrum and the composition of the medium (homogeneous vs inhomogeneous). This talk will elaborate on current understanding of the small field dosimetry. It will provide insight of the new IAEA/AAPM non‐complainant dosimetry (1) IPEM report 103 (2) and AAPM task group report 155(3). Explanation of the difficulties and possible solutions to accurately measure dose in small fields with various techniques (ion chamber, diode, diamond, TLD, films (radiographic and Gafchromic), MOSFET, bang gel, and Monte Carlo) will be elaborated. Correction factors that have been published will be presented and the consequences in accuracy for patient care will be discussed.Learning Objectives:1. Description of absolute and relative dosimetry2. Definition of small fields3. Choice of detector4. Correction factor5. Understanding the implication of small fields in clinical practice1.Alfonso P, Andreo P, Capote R, et al. A new formalism for refeence dosimetry of small and nonstandard fields. Med Phys 2008;35:5179‐5186.2.Aspradakis MM. Report No 103: Small Field MV dosimetry. York, England: IPEM; 2010.3. Das IJ, Francescon P, Ahnesjö A, et al. Task Group 155 report: Small fields and non‐equilibrium condition photon beam dosimetry. Med Phys (under review).
TH‐C‐217BCD‐06: Acoustic Radiation Force Based Imaging: An Overview
Authors: Nightingale K , Wang M , Rosenzweig S , Rotemberg V , Rouze N , Palmeri M 
Published: June 2012

Acoustic radiation force impulse (ARFI) based elasticity imaging methods have been under investigation in research laboratories for over 15 years. In ARFI imaging methods, temporally impulsive (i.e. < 1 msec) focused acoustic radiation force is used to mechanically excite tissue, and the dynamic displacement response is monitored using the same transducer and ultrasonic correlation based techniques. High resolution qualitative images can be generated that portray relative differences in tissue stiffness, maintaining structural integrity in heterogeneous media. These images are generated by monitoring the tissue response along the central axis of the excitation, and sequentially interrogating a 2D (or 3D) field of view (i.e. on‐axis, or ARFI imaging). Shear waves are generated by each of the ARFI excitations, and their propagation speed is related to the underlying tissue stiffness. Time‐of‐flight based algorithms have been developed to estimate shear wave propagation speed, and, under certain simplifying assumptions, the tissue stiffness can be quantified based upon these speeds. In the past 3 years, both Siemens Medical Systems and Supersonic Imagine (SSI) have released commercial ARFI based elasticity imaging products. This talk will provide an overview of the underlying physics of radiation force based elasticity imaging techniques, and a review of the initial clinical reports using these methods.Learning Objectives:1. To understand the differences between acoustic images, qualitative elasticity images, and shear wave images2. To understand the tradeoffs between resolution and accuracy in shear wave imaging3) to understand the limitations of the assumptions made by time‐of‐flight based algorithmsDisclosures: Some authors hold patents related to radiation force based techniques, and our lab has a research agreement with Siemens Medical Solutions. Funding: NIH R01 EB002132; R01 CA142824
TH‐C‐218‐02: Cranial SRS and SRT on a Siemens Artist Using the Brainlab IPlan Treatment Planning System
Authors: Gayou O 
Published: June 2012

Linear accelerator‐based stereotactic radiosurgery (SRS) or radiotherapy (SRT) is a well accepted technique for the treatment of cranial primary and metastatic lesions and acoustic neuromas. The requirements in terms of accuracy and reliability of the linac are more stringent for these modalities than they are for more highly fractionated treatments. However these requirements have been identified and standardized in the TG142 report on external beam quality assurance (QA). It is usually not difficult for a newly purchased modern linac to meet these requirements, giving users a wider variety of choice when considering starting an SRS/SRT program. The compatibility of these linacs with SRS/SRT‐specific equipment and software, such as cones, frames or treatment planning systems, must be established. I will report on the use at our institution of a Siemens Artiste™ linac for cranial SRS/SRT, in conjunction with the Brainlab iPlan® treatment planning system. I will discuss the various combinations of using the Brainlab SRS cones or the Siemens 160‐leaf multileaf collimator (160‐MLC) for beam shaping; the Brainlab frame or frameless system for immobilization; the Brainlab target positioning system or the Siemens MVision™ MV‐CBCT system for localization. I will describe the commissioning steps of the system, including data acquisition for beam modeling in iPlan® and end‐to‐end testing. Various issues that arose throughout the use of this Siemens/Brainlab hybrid system over the last 3 years will be discussed.Learning Objectives:1. To assess the safety and usefulness of a multivendor solution for cranial SRS/SRT.2. To understand the commissioning and quality assurance steps of a Siemens Artiste™ / Brainlab iPlan® hybrid system for cranial SRS/SRT3. To understand the limitations of the hybrid system.
TH‐D‐BRCD‐01: TG‐51 Addendum: New KQ Values
Authors: Rogers D 
Published: June 2012

The addendum to TG‐51, which is currently under review, will provide an expanded new set of beam quality conversion factors, kQ. The calculated values of kQ in the TG‐51 protocol are based on analytic calculations which make use of various tabulated values of measured and calculated factors uch as the water to air stopping‐power ratio, Pwall, Prepl and Pcel (for details see Ch 9 of the 2009 AAPM Summer School book, Med. Phys. Publishing, Madison, WI). However, with the development of the EGSnrc Monte Carlo system (Kawrakow, Med Phys 27(2000) 499) it is possible to accurately calculate the response of ion chambers. Also computers have became faster per unit cost and clever variance reduction techniques have been implemented for doing ion chamber calculations in complex geometries (Wulff et al, Med Phys 35(2008)1328). Hence ab initio Monte Carlo calculations of kQ have become both accurate and feasible using large clusters of computers. Values of kQ have been calculated this way for a total of 33 commonly used cylindrical ion chambers (Muir and Rogers, Med Phys 37(2010)5939) and these kQ values are accurately fit as a quadratic function of the beam quality specifier, %dd(10)x. Detailed estimates of the systematic uncertainty in these calculations have been made and range between 0.6% and 1.0%, depending on the assumptions made. The largest component is the uncertainty (previously 0.5%) in the assumed constancy with beam quality of (W/e)air, which relates the energy deposited in the cavity to the charge released in the air. In a detailed comparison of the calculated kQ values to the extensive high‐quality measurements by McEwen (Med Phys 37(2010)2179), Muir et al (Med Phys 38 (2011) 4600) found the mean percentage differences between the calculations and the experiments are 0.08(0.17), 0.07(0.32) and 0.23(0.31) in 6, 10 and 25 MV beams respectively (bracketed values are rms deviations). These discrepancies are well within the stated uncertainties of the measurements (about 0.3% to 0.4%) and the calculations (about 0.3% to 0.4% ignoring W/e uncertainties and assuming correlated uncertainties in photon cross section). These and similar comparisons for plane‐parallel chambers (Muir et al, Med Phys 39(2012) 1618) can be used to set an upper limit of 0.36% on the variation of (W/e)air with beam quality between 60Co and 25 MV beams (95% confidence). More importantly, the close agreement with experiment gives confidence in the accuracy of the Monte Carlo calculated values of kQ with a 68% confidence uncertainty of between 0.4% and 0.5%.The addendum to TG‐51 recommends use of these calculated values of kQ for the 21 ion chambers which meet the requirements for a reference class ion chamber.Learning Objectives1. To become aware of the new addendum to TG‐51 regarding reference dosimetry in photon beams.2. Understand how ab initio calculations of the TG‐51's beam quality conversion factor, kQ, are done3. Understand the uncertainties involved in ab initio calculations of kQ.
TH‐E‐213AB‐01: Review of Radiobiological Principles of Radiotherapy and Radiation Protection
Authors: Orton C , Borras C 
Published: June 2012

Mechanisms by which radiation kills cells and ways cell damage can be repaired will be reviewed. The effect of radiobiological parameters which we can control for radiotherapy will be discussed including dose/fraction, number of fractions, time between fractions, overall treatment time, and the LET of the radiation. Reasons why we fractionate the way we do will be discussed, along with how sparing of normal tissues using conformal techniques might affect optimal fractionation. The linear‐quadratic model for cell survival for high and low dose rate treatments and the effect of repopulation will be presented and discussed. Radiation protection and the dose response of normal tissues will be reviewed, including effects on the developing embryo/fetus. The concepts of equivalent dose and effective dose in medical radiation protection, the Sv unit, and radiation and tissue‐weighting factors will be presented. The latest information on human data on radiation‐induced cancer, genetic effects and harmful tissue effects, especially cerebrovascular and cardiovascular diseases as well as cataract formation, published by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), the Biological Effects of Ionizing Radiation (BEIR) Committee and the International Commission on Radiological Protection (ICRP) will be examined. Estimates of risk per unit exposure will be presented. Their use in the development of radiation protection guidelines and standards will be discussed.Learning Objectives1. To understand the radiobiological basis of radiation protection standards.2. To define the radiation protection magnitudes and units, their values and their practical measurement.3. To distinguish between stochastic and deterministic effects.
TH‐E‐213AB‐02: Review of the Radiobiological Principles of Radiation Protection
Authors: Borras C 
Published: June 2012

The radiobiological principles underlying radiation protection guidelines will be reviewed, analyzing the published results of the effects of ionizing radiation at the cellular level, in animal experiments and, especially, in epidemiological studies. To ensure a consistent terminology, the radiation dosimetry terms used in radiation biology and in radiation protection will be presented. The concepts of equivalent dose vs dose equivalent as well as the term effective dose, the Gray and Sv units, and the radiation and tissue weighting factors will be explained and illustrated. Human data on radiation induced cancer, including increases in the risk of second cancers following radiation therapy, as well as data on radiation induced tissue reactions, published by the International Commission on Radiological Protection (ICRP), the National Council on Radiation Protection and Measurements (NCRP) and the Biological Effects of Ionizing Radiation (BEIR) Committee, with their latest estimates of risk per unit dose, will be introduced. The dose response of normal tissues will be discussed, including effects on children and the developing embryo and fetus. Recent findings in NCRP and ICRP publications, which include follow up times for some tissues much longer than those common in radiotherapy (up to 20 to 40 versus 5 to 10 years), will be assessed. In particular, current information on acute and chronic radiation syndromes, as well as the newly proposed threshold dose of 0.5 Gy for cataract induction and cardiovascular effects, will be examined. The impact of the new findings and recommendations on the development of radiation protection guidelines and standards, especially in the International Basic Safety Standards on Protection against Ionizing Radiation and for the Safety of Radiation Sources (BSS), soon to be adopted world‐wide, will be evaluated.Learning Objectives:1. To define the radiation protection magnitudes and units, their values and their practical measurement2. To understand the radiobiological basis of radiation protection standards3. To distinguish between stochastic effects and tissue reactions
TH‐E‐BRCD‐01: Automatic Treatment Planning ‐ an MCO Perspective
Authors: Craft D 
Published: June 2012

We review three multi‐criteria optimization (MCO) approaches for automatic IMRT treatment planning: goal programming, prioritized optimization, and Pareto surface based MCO. After comparing and contrasting these approaches, we describe a hybrid approach where in step one — using any of those alternatives — a “first pass” plan is constructed. When this plan is presented to the treatment planner (or physician), the planner is allowed to navigate on a Pareto surface centered around that plan, allowing for a tuning of the plan. For this tuning step to be most useful, we require directly deliverable MCO (DMCO), by which we mean navigating on the Pareto surface in such a way that the plan you are currently viewing is ready‐to‐go from a delivery perspective (i.e. it does not need to be leaf sequenced first, the multi‐leaf collimator segmentation has already been done). We discuss current approaches to solving this DMCO problem, and finish with a discussion of how the above ideas apply to automatic volumetric modulated arc therapy (VMAT) planning.Learning objectives:1. Understand three types of multi‐criteria optimization: goal programming, prioritized optimization, and Pareto surface based MCO2. Understand the idea of Pareto surface navigation refinement of an automatically generated plan.3. Understand directly deliverable navigation. Research sponsored in part by RaySearch Laboratories.
Screening Education And Recognition in Community pHarmacies of Atrial Fibrillation to prevent stroke in an ambulant population aged ≥65 years (SEARCH-AF stroke prevention study): a cross-sectional study protocol
Authors: Lowres Nicole , Freedman Saul Benedict , Redfern Julie , McLachlan Andrew , Krass Ines , Bennett Alexandra , Briffa Thomas , Bauman Adrian , Neubeck Lis 
Published: June 2012

BackgroundAtrial fibrillation (AF) is associated with a high risk of stroke and may often be asymptomatic. AF is commonly undiagnosed until patients present with sequelae, such as heart failure and stroke. Stroke secondary to AF is highly preventable with the use of appropriate thromboprophylaxis. Therefore, early identification and appropriate evidence-based management of AF could lead to subsequent stroke prevention. This study aims to determine the feasibility and impact of a community pharmacy-based screening programme focused on identifying undiagnosed AF in people aged 65 years and older.Methods and analysisThis cross-sectional study of community-based screening to identify undiagnosed AF will evaluate the feasibility of screening for AF using a pulse palpation and handheld single-lead electrocardiograph (ECG) device. 10 community pharmacies will be recruited and trained to implement the screening protocol, targeting a total of 1000 participants. The primary outcome is the proportion of people newly identified with AF at the completion of the screening programme. Secondary outcomes include level of agreement between the pharmacist's and the cardiologist's interpretation of the single-lead ECG; level of agreement between irregular rhythm identified with pulse palpation and with the single-lead ECG. Process outcomes related to sustainability of the screening programme beyond the trial setting, pharmacist knowledge of AF and rate of uptake of referral to full ECG evaluation and cardiology review will also be collected.Ethics and disseminationPrimary ethics approval was received on 26 March 2012 from Sydney Local Health District Human Research Ethics Committee—Concord Repatriation General Hospital zone. Results will be disseminated via forums including, but not limited to, peer-reviewed publication and presentation at national and international conferences.Clinical trials registration numberACTRN12612000406808.
Reversible heart failure: toxins, tachycardiomyopathy and mitochondrial abnormalities
Authors: Morris Paul D , Robinson Tim , Channer Kevin S 
Published: June 2012

Abstract
Heart failure is usually a relentless condition associated with a poor prognosis. Triggered by a physiological insult, maladaptive neurohumoral processes result in an ever-spiralling deterioration of cardiovascular function. However, there are certain underlying conditions which are associated with a temporary reduction in contractile function leading to reversible heart failure. These conditions affect a relatively small number of patients when compared with heart failure secondary to inherited cardiomyopathies and ischaemic heart disease. There are two broad mechanisms responsible for reversible myocyte dysfunction: acute inflammatory activation in which cytokines depress myocyte function, and toxic effects in which there is impairment of intra-cellular energetics. In this review, we discuss reversible heart failure caused by toxic effects. These effects can be caused by drugs (prescribed and illicit) and by tachycardic arrhythmia (tachycardiomyopathy), and are caused by abnormalities of mitochondrial function and myocytic calcium processing. The underlying pathological mechanisms, clinical features and management options are discussed, illustrated by clinical case studies.
MDM2 Overexpression Deregulates the Transcriptional Control of RB/E2F Leading to DNA Methyltransferase 3A Overexpression in Lung Cancer
Authors: Tang Yen-An , Lin Ruo-Kai , Tsai Yo-Ting , Hsu Han-Shui , Yang Yi-Chieh , Chen Chih-Yi , Wang Yi-Ching 
Published: June 2012

Abstract
Purpose: Overexpression of DNA 5′-cytosine-methyltransferase 3A (DNMT3A), which silences genes including tumor suppressor genes (TSG), is involved in many cancers. Therefore, we examined whether the transcriptional deregulation of RB/MDM2 pathway was responsible for DNMT3A overexpression and analyzed the therapeutic potential of MDM2 antagonist for reversing aberrant DNA methylation status in lung cancer.
Experimental Design: The regulation of DNMT3A expression and TSG methylation status by RB/MDM2 was assessed in cancer cell lines and patients. The effects of Nutlin-3, an MDM2 antagonist, on tumor growth in relation to DNMT3A expression and TSG methylation status were examined by xenograft model.
Results: We found that RB suppressed DNMT3A promoter activity and mRNA/protein expression through binding with E2F1 protein to the DNMT3A promoter, leading to the decrease of methylation level globally and TSG specifically. In addition, MDM2 dramatically induced DNMT3A expression by negative control over RB. In clinical study, MDM2 overexpression inversely correlated with RB expression, while positively associating with overexpression of DNMT3A in samples from patients with lung cancer. Patients with high MDM2 and low RB expression showed DNMT3A overexpression with promoter hypermethylation in TSGs. Treatment with Nutlin-3, an MDM2 antagonist, significantly suppressed tumor growth and reduced DNA methylation level of TSGs through downregulation of DNMT3A expression in xenograft studies.
Conclusions: This study provides the first cell, animal, and clinical evidence that DNMT3A is transcriptionally repressed, in part, by RB/E2F pathway and that the repression could be attenuated by MDM2 overexpression. MDM2 is a potent target for anticancer therapy to reverse aberrant epigenetic status in cancers. Clin Cancer Res; 18(16); 4325–33. ©2012 AACR.
Validation of the Hematopoietic Cell Transplantation-Specific Comorbidity Index: a prospective, multicenter GITMO study
Authors: Raimondi Roberto , Tosetto Alberto , Oneto Rosi , Cavazzina Riccardo , Rodeghiero Francesco , Bacigalupo Andrea , Fanin Renato , Rambaldi Alessandro , Bosi Alberto 
Published: June 2012

Abstract
The development of tools for the prediction of nonrelapse mortality (NRM) after allogeneic hematopoietic stem cell transplantation (HSCT) would offer a major guidance in the therapeutic decision. Recently, the Hematopoietic Cell Transplantation-Specific Comorbidity Index (HCT-CI) has been associated with increased NRM risk in several retrospective studies, but its clinical utility has never been demonstrated prospectively in an adequately sized cohort. To this aim, we prospectively evaluated a consecutive cohort of 1937 patients receiving HSCT in Italy over 2 years. HCT-CI was strongly correlated with both 2-year NRM (14.7%, 21.3%, and 27.3% in patients having an HCT-CI score of 0, 1-2, and ≥ 3, respectively) and overall survival (56.4%, 54.5%, and 41.3%, respectively). There was an excellent calibration between the predicted and observed 2-year NRM in patients having an HCT-CI score of 0 and 1-2, whereas in the ≥ 3 group the predicted NRM overestimated the observed NRM (41% vs 27.3%). HCT-CI alone was the strongest predictor of NRM in patients with lymphoma, myelodysplastic syndrome, and acute myeloid leukemia in first remission (c-statistics 0.66, 064, and 0.59, respectively). We confirm the clinical utility of the HCT-CI score that could also identify patients at low NRM risk possibly benefiting from an HSCT-based treatment strategy.