bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Dispute Concerning the TRIPS Agreement: The United States and China in the WTO
Authors: Roy Alpana
Published: March 2008

On 10 April 2007, the United States filed a complaint against China in the dispute settlement body of the World Trade Organization (WTO) with respect to the protection and enforcement of intellectual property rights. The United States has requested “consultations” with China on four separate matters: the threshold requirements for criminal procedures and penalties in Chinese law; the disposal of goods confiscated by Chinese customs authorities that infringe intellectual property rights; the issue of copyright and related rights protection for works that have not been authorized for publication or distribution within China; and the unavailability of criminal procedures and penalties for persons engaged in unauthorized reproduction or unauthorized distribution of copyrighted works. Despite widespread allegations of intellectual property piracy, this is the first official complaint that has been lodged against China in the WTO with respect to its obligations under the TRIPS Agreement. While consultations with China have been requested, no dispute settlement panel has been established with respect to the complaint. This note will outline the complaint against China in more detail.
Go and Tend the Earth: A Jewish View on an Enhanced World
Authors: Zoloth Laurie
Published: March 2008

Consider the thought experiment offered at the conference that generated this collection of essays: in this fantasy, face transplants are safe and effective. A young woman is the victim of a devastating accident. A face transplant will enable her to live a completely normal life. But, say she is African American, or Asian. Would it be ethically permissible to allow her to take the face of a Caucasian woman? Or, say you have a child with a muscle wasting disorder. Would it be permissible to alter his muscle repair system so that he not only does not have the genetic variation that causes the disease, but he has the capacity for enhanced muscular strength, beyond that of his peers, such that he could become a big league pitcher?
“Enhancing Life?” Perspectives from Traditional Chinese Value-Systems
Authors: Kirkland Russell
Published: March 2008

In his introduction to this symposium, “Religions and Cultures of East and West: Perspectives on Bioethics,” Dr. Robert Sade defined its purpose as follows: “The objective of [our] discussions…is to explore the limits of enhancement technologies in light of what makes us essentially human, in the view of world-wide cultures and religions.”

These issues would seem to be at the cutting edge of any informed deliberation concerning the merits of “human enhancement” technologies. For instance, the issue of how “what makes us essentially human” affects our reflection on issues of technological “life enhancement” is raised in a 2007 book by Harvard professor Michael J. Sandel,The Case Against Perfection: Ethics in the Age of Genetic Engineering.
Enhancement Technologies and the Person: Christian Perspectives
Authors: Lustig Andrew
Published: March 2008

Current discussions of so-called “enhancement” technologies immediately involve matters of definition, because the distinctions between enhancement and therapy invite ambiguity. Therapy is generally defined as the prevention or cure of disease, or as the restoration or approximation of return to normal physiological function. Enhancement is defined as the alteration of individual (or group) characteristics, traits, and abilities (both health- and non-health-related) beyond a measurable baseline of normal function. Both notions rely on shared understandings of disease and illness, which depend in turn on the ways that we conceptualize and operationalize judgments of normalcy. Both notions have therefore generated significant controversy among philosophers of medicine, with the result that blanket distinctions between therapy and enhancement appear unlikely to convince everyone.
Enhancement Technologies and the Person: An Islamic View
Authors: Athar Shahid
Published: March 2008

Physically and intellectually, man is not the same as a million years ago. This “improvement” in humans has occurred over a period of time and not as a result of any outside biotechnical intervention. So, the question is what is the need now? The fine line between what can be done technically and what should be done morally is the reason for biomedical ethics. What is the nature of man, and what is his relationship with his creator and his environment? Whose interest (man, God, and environment) are we as scientists and physicians to guard? What are the rights of the unborn, and who protects those rights? While seeking medical treatment for infertility and reconstructive surgery for a malformation or genetic manipulation for a genetic disease might perhaps be appropriate and recommended, is it also appropriate to create a super healthy, super human with genetic manipulation? If so, then are we embarking on the path of ethnic cleansing of humans of lesser ability, and is it appropriate to discriminate? In this paper, such questions and concerns are discussed from an Islamic perspective.
The POLST (Physician Orders for Life-Sustaining Treatment) Paradigm to Improve End-of-Life Care: Potential State Legal Barriers to Implementation
Authors: Hickman Susan E. , Sabatino Charles P. , Moss Alvin H. , Nester Jessica Wehrle
Published: March 2008

The Physician Orders for Life-Sustaining Treatment (POLST) Paradigm is designed to improve end-of-life care by converting patients’ treatment preferences into medical orders that are transferable throughout the health care system. It was initially developed in Oregon, but is now implemented in multiple states with many others considering its use. Accordingly, an observational study was conducted in order to identify potential legal barriers to the implementation of a POLST Paradigm. Information was obtained from experts at state emergency medical services and long-term care organizations/agencies in combination with a review of relevant state law. Legal analysis of survey responses and existing laws identified several potential state legal barriers to a POLST Paradigm implementation. The most potentially problematic barriers are detailed statutory specifications for out-of-hospital DNR (do not resuscitate) protocols (n = 9 states). Other potential barriers include limitations on the authority to consent to forgo life-sustaining treatments (n = 23 states), medical preconditions (n = 15), and witnessing requirements (n = 12) for out-of-hospital DNR protocols.
Race, Religion, and Informed Consent — Lessons from Social Science
Authors: Matthew Dayna Bowen
Published: March 2008

Patients belonging to ethnic, racial, and religious minorities have been all but excluded from the legal academy’s ongoing conversation about informed consent. Perhaps this is just as well, since the conversation appears to have concluded that the doctrine has failed to serve as a meaningful regulation of clinical relationships. Informed consent does not operate in practice the way it was intended in theory. More than a decade ago, Peter Schuck noted the “informed consent gap” that distinguishes the “proper” law of informed consent “on the books” from the actual consent law in action, and called for a more contextualized approach to informed consent. Susan Wolf later called for a systemic approach to informed consent in order to accommodate multiple decision points in the managed care setting. Some reformers have sought enhancements to expand the doctrine.
Teaching Health Law
Authors: Frisch Paul , Hughes Randall L. , Killgore Joan B.
Published: March 2008

I come from a medical family. My father and uncle were physicians, and my father also chaired a department at a West Coast medical school for over 30 years. I am sure I got my interest in teaching from him. My brother is a physician and is currently the safety and quality officer of a Canadian province. My mother operated the last non-automated medical laboratory in my state. I have always understood what sacrifices are made by health care professionals, and I think I have managed to learn a bit about their motivations as well.

I was in private practice for ten years with litigation firms, and the last five years of that time I worked for a firm that specialized in professional liability defense and health law.
Setting Expectations for the Federal Role in Public Health Emergencies
Authors: Hargan Eric D.
Published: March 2008

I would like to begin by discussing the legal and administrative framework of the role of the federal government in public health. At the heart of it is, of course, the Constitution. At the Department of Health and Human Services (HHS) we depend, as does much of the federal government, on our power to regulate interstate commerce. Since the Supreme Court in 1942 removed essentially any restraint from the meaning of interstate commerce in Wickard v. Filburn, the federal government has been regulating with wide latitude, in spite of small and, arguably, equivocal reverses in recent years. However, even though the Supreme Court no longer provides any real constitutional check on the federal government's interstate commerce power, some other restraints persist. For example, many parts of the health system have traditionally been deemed inherently state functions, such as the licensing and disciplining of doctors, nurses, and pharmacists, as well as the practice of medicine itself.
Public Health Emergency Legal Preparedness: Legal Practitioner Perspectives
Authors: Kouzoukas Demetrios L.
Published: March 2008

This paper provides an overview of recent US Department of Health and Human Services (HHS) initiatives and efforts — under the leadership of the General Counsel, the Secretary, and the President — regarding legal preparedness for public health emergencies. In addressing this topic, the paper focuses on four core elements comprising public health legal preparedness:

(1)

effective legal authorities to support necessary public health activities;

(2)

competencies of public health professionals to know and then to apply those laws;

(3)

coordination of the application of laws across jurisdictions (local, state, tribal, federal, and international) and across multiple sectors; and

(4)

information and best practices in public health law.
Assessing Competencies for Public Health Emergency Legal Preparedness
Authors: Hodge James G. , Gebbie Kristine M. , Hoke Chris , Fenstersheib Martin , Hoffman Sharona , Lynk Myles
Published: March 2008

Among the many components of legal preparedness for public health emergencies is the assurance that the public health workforce and its private sector partners are competent to use the law to facilitate the performance of essential public health services and functions. This is a significant challenge. Multiple categories of emergencies, stemming from natural disasters to emerging infectious diseases, confront public health practitioners. Interpreting, assessing, and applying legal principles during emergencies are complicated by the changing legal environment and differences in governmental organization of emergency management functions. While law and legal competencies are essential to routine public health practices, once government declares a state of public health emergency or disaster, the legal landscape changes. Typical legal responses to protect the public's health may no longer be the norm. Public health practitioners, legal counsel, health care partners, and others need to be able to assess changing laws and policies and apply them in real-time.
Assessing Cross-Sectoral and Cross-Jurisdictional Coordination for Public Health Emergency Legal Preparedness
Authors: Hogan Rick , Bullard Cheryl H. , Stier Daniel , Penn Matthew S. , Wall Teresa , Cleland John , Burch James H. , Monroe Judith , Ragland Robert E. , Baker Thurbert , Casciotti John
Published: March 2008

A community's abilities to promote health and maximize its response to public health threats require fulfillment of one of the four elements of public health legal preparedness, the capacity to effectively coordinate law-based efforts across different governmental jurisdictions, as well as across multiple sectors and disciplines. Government jurisdictions can be viewed “vertically” in that response efforts may entail coordination in the application of laws across multiple levels, including local, state, tribal, and federal governments, and even with international organizations. Coordination of legal responses to public health emergencies also may involve a horizontal dimension comprising numerous and diverse sectors, such as public health, public and private health care, emergency management, education, law enforcement, the judiciary, and the military.

Although responses to many acute health threats can implicate multiple jurisdictions and sectors, the jurisdictional and sectoral dimensions of legal preparedness are complex and may vary substantially by the nature of a threat, its geographic and geopolitical extent, and the operational response demanded.
Improving Laws and Legal Authorities for Public Health Emergency Legal Preparedness
Authors: Pestronk Robert M. , Kamoie Brian , Fidler David , Matthews Gene , Benjamin Georges C. , Bryan Ralph T. , Tuch Socrates H. , Gottfried Richard , Fielding Jonathan E. , Schmitz Fran , Redd Stephen
Published: March 2008

This paper is one of the four interrelated action agenda papers resulting from the National Summit on Public Health Legal Preparedness (Summit) convened in June 2007 by the Centers for Disease Control and Prevention and multi-disciplinary partners. Each of the action agenda papers deals with one of the four core elements of legal preparedness: laws and legal authorities; competency in using those laws; coordination of law-based public health actions; and information. Options presented in this paper are for consideration by policymakers and practitioners — in all jurisdictions and all relevant sectors and disciplines — with responsibilities for all-hazards emergency preparedness.

One expert's framing of the mission of public health may help improve understanding of the range of hazards for which to be legally prepared. These hazards include urgent realities — such as chronic disease, injury, disabilities, conventional communicable diseases, and an aging and obese population — and urgent threats, such as pandemic influenza, natural disasters, and terrorism.
Improving Competencies for Public Health Emergency Legal Preparedness
Authors: Gebbie Kristine M. , Hodge James G. , Meier Benjamin Mason , Barrett Drue H. , Keith Priscilla , Koo Denise , Sweeney Patricia M. , Winget Patricia
Published: March 2008

This paper is one of the four interrelated action agenda papers resulting from the National Summit on Public Health Legal Preparedness (Summit) convened in June 2007 by the Centers for Disease Control and Prevention, and multi-disciplinary partners. Each of the action agenda papers deals with one of the four core elements of legal preparedness: laws and legal authorities; competency in using those laws; and coordination of law-based public health actions; and information.

This action agenda offers options for consideration by those responsible for or interested in ensuring that public health professionals, their legal counsels, and relevant partners understand the legal framework in which they operate and are competent in applying legal authorities to public health emergency preparedness.

Competencies are critical to an individual's ability to make effective legal response to all-hazards public emergencies.
Promotion Potential of Madder Color in a Medium‐Term Multi‐Organ Carcinogenesis Bioassay Model in F344 Rats
Authors: Yokohira M. , Yamakawa K. , Hosokawa K. , Matsuda Y. , Kuno T. , Saoo K. , Imaida K.
Published: March 2008

ABSTRACT:  A medium‐term multi‐organ carcinogenesis bioassay in rats was conducted to assess any possible tumor promoting effects of madder color extracted from the root of madder. Male F344 rats were divided into 5 groups of 20 each. All rats of groups 1 to 4 were given DMD treatment, consisted of multicarcinogens, N‐nitrosodiethylamine (DEN), N‐methyl‐N‐nitrosourea (MNU), and N‐bis (2‐hydroxypropyl) nitrosamine (DHPN), for 4 wk, while group 5 served as untreated control without carcinogens. The animals were then administered a basal diet containing madder color at doses of 5.0% (group 1), 2.5% (group 2 with 0.75% additional dextrin), or 0 (groups 3 with 1.5% additional dextrin, 4 without dextrin and 5) for the following 28 wk (total 32 wk). The total amount of dextrin in groups 1 to 3 diets was adjusted to 1.5% by extra dextrin because madder color powder contained dextrin. Key organs were observed histopathologically and glutathione S‐transferase placental form (GST‐P) positive foci of the liver were quantified. In the liver, 5.0% and 2.5% treated groups showed statistically significant dose‐related increases in both number and area of GST‐P positive foci, number: 2.81 ± 0.90 and 1.96 ± 0.93 (groups 1 and 2), area: 0.99 ± 2.49 and 0.37 ± 0.77, as compared with control, number: 0.87 ± 0.72, area: 0.06 ± 0.06 (group 3). In the kidneys, incidences (and numbers) of adenoma treated with 5.0% and 2.5%, 47.4% (0.20 ± 0.24), and 47.4% (0.13 ± 0.15) (groups 1 and 2) were significantly increased compared to control, 0% (0) (group 3). In conclusion, madder color demonstrated significant tumor promoting effects in the liver and kidneys in the DMD model.
Formulation of a Cosurfactant‐Free O/W Microemulsion Using Nonionic Surfactant Mixtures
Authors: Cho Y.‐H. , Kim S. , Bae E.K. , Mok C.K. , Park J.
Published: March 2008

ABSTRACT:  A cosurfactant‐free O/W microemulsion composed of oil, a mixture of hydrophilic and hydrophobic surfactants, and water has been developed using food‐grade components as a nutrient delivery system. We started our investigation to monitor the phase behavior of this system based on a hydrophilic surfactant (Tween 80). From a phase diagram, the weight ratio of 5.4:33.8:60.8 = oil:surfactant:water was selected as a combination ratio for the O/W microemulsion system. We also investigated the combination effect of different hydrophobic surfactants to Tween 80 on microemulsion formation. Use of hydrophobic surfactants with Tween 80 produced smaller droplets than Tween 80 alone. Rheological studies showed that all microemulsions followed shear‐thinning behavior. The turbidity of microemulsions did not change after accelerated stability tests, indicating that this microemulsion system was stable under the given harsh conditions. When docosahexaenoic acid (DHA) oil was applied to this microemulsion system, the particle size and the turbidity were not significantly changed. Dilution with a different aqueous medium, either water or acidic fluid, did not significantly change the microemulsion turbidity. DHA oil incorporated in microemulsion showed higher oxidation stability than free DHA oil.
Influence of Probiotic Lactobacillus acidophilus and L. helveticus on Proteolysis, Organic Acid Profiles, and ACE‐Inhibitory Activity of cheddar Cheeses Ripened at 4, 8, and 12 °C
Authors: Ong L. , Shah N.P.
Published: March 2008

ABSTRACT:  The influence of adjunct bacteria on composition of cheeses, organic acid profiles, proteolysis, and ACE‐inhibitory activity during ripening at 4, 8, and 12 °C for 24 wk was investigated. cheddar cheeses were made with starter lactococci (control), Lactobacillus acidophilus L10, and starter lactococci (L10), and L. acidophilus L10, L. helveticus H100, and starter lactococci (H100). The counts of L. acidophilus in L10 cheeses remained at >106 colony forming units (CFU)/g after 24 wk of ripening at 4, 8, and 12 °C. Concentrations of lactic, acetic, and propionic acids of the L10 and H100 cheeses were significantly higher than those of the control cheeses after 24 wk of ripening (P < 0.05). Proteolysis of the cheeses was improved as the ripening temperature increased. Water‐soluble nitrogen, trichloroacetic acid soluble nitrogen, and phosphotungstic acid soluble nitrogen of L10 and H100 cheeses were significantly higher than those of the control cheeses (P < 0.05). Increase in ripening temperature from 4 °C to 8 and 12 °C increased the percentage of ACE inhibition. The IC50 value among cheeses ripened at 4, 8, and 12 °C, however, was not significantly different (P > 0.05). Hence, probiotic L. acidophilus L10 can be added into cheddar cheeses to improve proteolysis and ACE‐inhibitory activity.
Cortical Networks Grown on Microelectrode Arrays As a Biosensor for Botulinum Toxin
Authors: Scarlatos A. , Cadotte A.J. , DeMarse T.B. , Welt B.A.
Published: March 2008

ABSTRACT: Botulinum toxin (BoNT) is a potent neurotoxin produced by toxigenic strains ofClostridium botulinum. Botulinum toxin poses a major threat since it could be employed in a deliberate attack on the U.S. food supply. Furthermore, BoNT may be liberated in any insufficiently processed food containing a reduced oxygen atmosphere. Hence, rapid and reliable detection of BoNT in foods is necessary to reduce risks posed through food contamination. We present a BoNT biosensor employing living neural cultures grownin vitroon microelectrode arrays (MEAs). An MEA is a culture dish with a grid of electrodes embedded in its surface, enabling extracellular recording of action potentials of neural cultures grown over the array. Pharmaceutical grade BoNT A was applied to the media bath of mature cortical networks cultured on MEAs. Both spontaneous and evoked activities were monitored over 1 wk to quantify changes in the neural population produced by BoNT A. Introduction of BoNT A resulted in an increased duration and number of spikes in spontaneous and evoked bursts relative to control cultures. Increases were significant within 48 h of BoNT A dosage (P< 0.05). Application of BoNT A also induced unique oscillatory behavior within each burst that is reminiscent of early developmental activity patterns rather than the mature cultures used here. Three or more activity peaks were observed in 50% of the BoNT dosed cultures. Control cultures exhibited only a single activity peak. Thus activity of these cortical networks measured with MEAs could provide a valuable substrate for BoNT detection.
Biochemical and Conformational Changes of Myosin Purified from Pacific Sardine at Various pHs
Authors: Park J.D. , Yongsawatdigul J. , Choi Y.J. , Park J.W.
Published: March 2008

ABSTRACT:  Biochemical and conformational changes of purified sardine myosin were investigated at various pHs. The purity of myosin, as determined by SDS‐PAGE, was approximately 94.6%. One major band at 205 kDa, corresponding to myosin heavy chain, and 3 light chains at 31, 24, and 23 kDa were observed on the SDS‐PAGE gel. The greatest myosin protein solubility was observed at pH 7 and remained constant up to pH 11. Sardine myosin showed no solubility at pHs 2.5 to 5.0. Three endothermic peaks were obtained for samples prepared at pHs 7 and 10, while no peaks were shown for pH 2 samples, indicating chemical denaturation of myosin occurred before thermal treatment. The greatest Ca2+‐ATPase activity was observed at pH 7, while no activity was observed between pHs 2 and 5 and at pH 11. Total sulfhydryl content was not measured at pHs 2.5 to 4 while the greatest measure was obtained for samples at pH 5.5. Surface hydrophobicity was not detected from pHs 2.5 to 5.0; thereafter the content remained consistent through pH 11. Storage modulus, indicating the elastic element of myosin gels, was minimally affected at pH 2, indicating myosin was chemically denatured before the temperature sweep treatment. However, at pH 10, the thermal exposure of myosin, as evidenced by dynamic thermograms with deeper valleys at 40 to 60 °C, was noted, indicating myosin was not damaged by adjustment to pH 10 and therefore was still able to undergo thermal gelation.
Measurement of the Oxidation–Reduction Potential of cheddar Cheese
Authors: Topcu A. , McKinnon I. , McSweeney P.L.H.
Published: March 2008

ABSTRACT:  The objective of this study was to develop a method to measure the oxidation–reduction (redox) potential of hard cheeses such as cheddar and to investigate the impact on this parameter of measurement temperature, and factors associated with electrochemical cell design such as distance between reference and working electrodes and depth into the cheese of the platinum electrodes. For this purpose, a novel, self‐sealing, platinum working electrode was constructed which was thin and flexible enough to be inserted directly into the cheese sample. A calomel electrode was used as the reference electrode and the circuit was completed with a 3 M KCl salt bridge. The physical orientation of electrodes, such as distance between reference electrode and working electrode, had a substantial effect on equilibrium time for redox potential measurement. The time required for redox potential to reach equilibrium was 2 d in cheddar cheese and the optimum distance between the platinum and calomel electrodes was 2.5 cm. The fastest equilibration time was obtained when the working electrode was inserted 5 or 6 cm into the cheese. Temperature also had an important effect on redox potential. The shortest time to reach equilibrium of potential was at room temperature (20 °C), but it was not practical to keep cheese at this temperature for a period of 2 d. Therefore, redox measurement at 12 °C was recommended in spite of the longer equilibration time compared with room temperature. The results of this study suggest that the novel platinum working electrode allows reproducible measurement of the oxidation–reduction potential of cheddar cheese.
Short‐term temporal variability in the abundance of tropical dung beetles
Authors: ANDRESEN ELLEN
Published: March 2008

Abstract. 

Dung beetles are increasingly being used as a focal taxon in biodiversity and conservation studies. One of the alleged advantages of these insects is that sampling conducted in a few days can yield accurate data.

Dung beetles were collected twice, within a week, in a tropical dry forest in Mexico. The abundance of one species,Onthophagus landolti, increased 16 times in one of the habitats, over a period of a few days. Consequently, conclusions regarding differences between both habitats differed greatly depending on which sampling period was considered.

Short‐term temporal variability in the abundance of dung beetles, particularly if spatially asymmetric, must carefully be considered when designing sampling protocols for this group of insects in dry tropical forests.
A habitat suitability model for the narrow‐headed ant, Formica exsecta, evaluated against independent data
Authors: LITTLEWOOD NICK A. , YOUNG MARK R.
Published: March 2008

Abstract. 

Predictive models are frequently used to assist forecasts of species’ distributions. For rare species, this approach can provide insights into habitat utilisation and potential habitat suitability that can assist conservation action. However the technique has seldom been used for invertebrates.

A habitat suitability model was constructed for the rare ant, Formica exsecta, at Glenmore, a pinewood site in Scotland that contains a significant proportion of the UK population of this species. A range of botanical and environmental variables were surveyed within cells in a grid structure. The model successfully re‐classified 87% of cells according to the presence/absence of ant nests. When subject to a jackknife procedure, 70% of cells were successfully re‐classified and the median predicted probability of presence in occupied cells was significantly greater than in unoccupied cells.

The model was further evaluated against three independent datasets with rates for successful predictions of 70%, 62.5% and 25%. The performance declined with increased distance from the area from which calibration data were collected.

We conclude that caution is required when a model is validated purely by reference to the data from which it was constructed and not against independent data. However, the process can provide useful insights into habitat suitability for rare invertebrates that can assist rapid assessment of potential ranges for conservation measures such as restoration of populations.
A deformable phantom for 4D radiotherapy verification: Design and image registration evaluation
Authors: Serban Monica , Heath Emily , Stroian Gabriela , Collins D. Louis , Seuntjens Jan
Published: March 2008

Motion of thoracic tumors with respiration presents a challenge for three‐dimensional (3D) conformal radiation therapy treatment. Validation of techniques aimed at measuring and minimizing the effects of respiratory motion requires a realistic deformable phantom for use as a gold standard. The purpose of this study was to develop and study the characteristics of a reproducible, tissue equivalent, deformable lung phantom. The phantom consists of a Lucite cylinder filled with water containing a latex balloon stuffed with dampened natural sponges. The balloon is attached to a piston that mimics the human diaphragm. Nylon wires and Lucite beads, emulating vascular and bronchial bifurcations, were uniformly glued at various locations throughout the sponges. The phantom is capable of simulating programmed irregular breathing patterns with varying periods and amplitudes. A tissue equivalent tumor, suitable for holding radiochromic film for dose measurements was embedded in the sponge. To assess phantom motion, eight 3D computed tomography data sets of the static phantom were acquired for eight equally spaced positions of the piston. The 3D trajectories of 12 manually chosen point landmarks and the tumor center‐of‐mass were studied. Motion reproducibility tests of the deformed phantom were established on seven repeat scans of three different states of compression. Deformable image registration (DIR) of the extreme breathing phases was performed. The accuracy of the DIR was evaluated by visual inspection of image overlays and quantified by the distance‐to‐agreement (DTA) of manually chosen point landmarks and triangulated surfaces obtained from 3D contoured structures. In initial tests of the phantom, a 20‐mm excursion of the piston resulted in deformations of the balloon of 20 mm superior–inferior, 4 mm anterior–posterior, and 5 mm left–right. The change in the phantom mean lung density ranged from at peak exhale to at peak inhale. The SI displacement of the landmarks varied between and of the piston excursion for positions closer and farther away from the piston, respectively. The reproducibility of the phantom deformation was within the image resolution . Vector average registration accuracy based on point landmarks was found to be 0.5 (0.4 SD) mm. The tumor and lung mean 3D DTA obtained from triangulated surfaces were 0.4 (0.1 SD) mm and 1.0 (0.8 SD) mm, respectively. This phantom is capable of reproducibly emulating the physically realistic lung features and deformations and has a wide range of potential applications, including four‐dimensional (4D) imaging, evaluation of deformable registration accuracy, 4D planning and dose delivery.
An automated intensity‐weighted brachytherapy seed localization algorithm
Authors: Whitehead Gregory , Chang Zheng , Ji Jim
Published: March 2008

Brachytherapy has proven to be an effective treatment for various forms of cancer, whereby radioactive material is inserted directly into the body to maximize dosage to malignant tumors while preserving healthy tissue. In order to validate the preoperative or intraoperative dosimetric model, a postimplant evaluation procedure is needed to ensure that the locations of the implanted seeds are consistent with the planning stage. Moreover, development of an automated algorithm for seed detection and localization is necessary to expedite the postimplant evaluation process and reduce human error. Most previously reported algorithms have performed binary transforms on images before attempting to localize seeds. Furthermore, traditional approaches based upon three‐dimensional seed shape parameterization and matching require high resolution imaging. The authors propose a new computationally efficient algorithm for automatic seed localization for full three‐dimensional, low‐resolution data sets that directly applies voxel intensity to the estimation of both seed centroid location and angular seed orientation. Computer simulations, phantom studies, and in vivo computed tomography prostate seed imaging results show that the proposed algorithm can produce reliable results even for low‐resolution images.
Calibration of megavoltage cone‐beam CT for radiotherapy dose calculations: Correction of cupping artifacts and conversion of CT numbers to electron density
Authors: Petit Steven F. , van Elmpt Wouter J. C. , Nijsten Sebastiaan M. J. J. G. , Lambin Philippe , Dekker André L. A. J.
Published: March 2008

Megavoltage cone‐beam CT (MV CBCT) is used for three‐dimensional imaging of the patient anatomy on the treatment table prior to or just after radiotherapy treatment. To use MV CBCT images for radiotherapy dose calculation purposes, reliable electron density (ED) distributions are needed. Patient scatter, beam hardening and softening effects result in cupping artifacts in MV CBCT images and distort the CT number to ED conversion. A method based on transmission images is presented to correct for these effects without using prior knowledge of the object's geometry. The scatter distribution originating from the patient is calculated with pencil beam scatter kernels that are fitted based on transmission measurements. The radiological thickness is extracted from the scatter subtracted transmission images and is then converted to the primary transmission used in the cone‐beam reconstruction. These corrections are performed in an iterative manner, without using prior knowledge regarding the geometry and composition of the object. The method was tested using various homogeneous and inhomogeneous phantoms with varying shapes and compositions, including a phantom with different electron density inserts, phantoms with large density variations, and an anthropomorphic head phantom. For all phantoms, the cupping artifact was substantially removed from the images and a linear relation between the CT number and electron density was found. After correction the deviations in reconstructed ED from the true values were reduced from up to 0.30 ED units to 0.03 for the majority of the phantoms; the residual difference is equal to the amount of noise in the images. The ED distributions were evaluated in terms of absolute dose calculation accuracy for homogeneous cylinders of different size; errors decreased from to below in the center of the objects for the uncorrected and corrected images, respectively, and maximum differences were reduced from to , respectively. The presented method corrects the MV CBCT images for cupping artifacts and extracts reliable ED information of objects with varying geometries and composition, making these corrected MV CBCT images suitable for accurate dose calculation purposes.
An outlook on x‐ray CT research and development
Authors: Wang Ge , Yu Hengyong , De Man Bruno
Published: March 2008

Over the past decade, computed tomography(CT) theory, techniques and applications have undergone a rapid development. Since CT is so practical and useful, undoubtedly CT technology will continue advancing biomedical and non‐biomedical applications. In this outlook article, we share our opinions on the research and development in this field, emphasizing 12 topics we expect to be critical in the next decade: analytic reconstruction, iterative reconstruction, local/interior reconstruction, flat‐panel based CT, dual‐source CT, multi‐source CT, novel scanning modes, energy‐sensitive CT, nano‐CT, artifact reduction, modality fusion, and phase‐contrast CT. We also sketch several representative biomedical applications.
Geometric interpretation of the dose distribution comparison technique: Interpolation‐free calculation
Authors: Ju Tao , Simpson Tim , Deasy Joseph O. , Low Daniel A.
Published: March 2008

The dose comparison tool has been used by numerous investigators to quantitatively compare multidimensional dose distributions. The tool requires the specification of dose and distance‐to‐agreement (DTA) criteria for acceptable variations between the dose distributions. The tool then provides a comparison that simultaneously evaluates the dose difference and distance to agreement of the two dose distributions. One of the weaknesses of the tool is that the comparison requires one of the dose distributions to have a relatively high spatial resolution, with points spaced significantly closer than the DTA criterion. The determination of involves an exhaustive search process, so the computation time is significant if an accurate is desired. The reason for the need for high spatial resolution lies with the fact that the tool measures the closest point in one of the dose distributions (the evaluated distribution) with individual points of the other distribution (the reference distribution) when the two distributions are normalized by the dose difference and DTA criteria for the dose and spatial coordinates, respectively. The closest point in the evaluated distribution to a selected reference distribution point is the value of at that reference point. If individual evaluated dose distribution points are compared, the closest point may not accurately reflect the closest value of the evaluated distribution as if it were interpolated on an infinite resolution grid. Therefore, a reinterpretation of the distribution as the closest geometric distance between the two distributions is proposed. This is conducted by subdividing the evaluated distribution into simplexes; line segments, triangles, and tetrahedra for one, two, and three‐dimensional (3D) dose distributions. The closest distance between any point and these simplexes can be straightforwardly computed using matrix multiplication and inversion without the need of interpolating the original evaluated distribution. While an exhaustive search is still required, not having to interpolate the evaluated distribution avoids the drastic growth of calculation time incurred by interpolation and makes the tool more practical and more accurate. In our experiment, the geometric method accurately computes distributions between 3D dose distributions on a grid within two minutes.
Iterative sorting for four‐dimensional CT images based on internal anatomy motion
Authors: Zeng Rongping , Fessler Jeffrey A. , Balter James M. , Balter Peter A.
Published: March 2008

Current four‐dimensional (4D) computed tomography (CT) imaging techniques using multislice CT scanners require retrospective sorting of the reconstructed two‐dimensional (2D) CT images. Most existing sorting methods depend on externally monitored breathing signals recorded by extra instruments. External signals may not always accurately capture the breathing status and may lead to severe discontinuity artifacts in the sorted CT volumes. This article describes a method to find the temporal correspondences for the free‐breathing multislice CT images acquired at different table positions based on internal anatomy movement. The algorithm iteratively sorts the CT images using estimated internal motion indices. It starts from two imperfect reference volumes obtained from the unsorted CT images; then, in each iteration, thorax motion is estimated from the reference volumes and the free‐breathing CT images. Based on the estimated motion, the breathing indices as well as the reference volumes are refined and fed into the next iteration. The algorithm terminates when two successive iterations attain the same sorted reference volumes. In three out of five patient studies, our method attained comparable image quality with that using external breathing signals. For the other two patient studies, where the external signals poorly reflected the internal motion, the proposed method significantly improved the sorted 4D CT volumes, albeit with greater computation time.
How does CT image noise affect 3D deformable image registration for image‐guided radiotherapy planning?
Authors: Murphy Martin J. , Wei Zhouping , Fatyga Mirek , Williamson Jeffrey , Anscher Mitchell , Wallace Timothy , Weiss Elizabeth
Published: March 2008

Purpose: To measure the sensitivity of deformable image registration to image noise. Deformable image registration can be used to map organ contours and other treatment planning data from one CT to another. These CT studies can be acquired with either conventional fan‐beam CT systems or more novel cone‐beam CT techniques. However, cone‐beam CT images can have higher noise levels than fan‐beam CT, which might reduce registration accuracy. We have investigated the effect of image quality differences on the deformable registration of fan‐beam CTs and CTs with simulated cone‐beam noise. Method: Our study used three CT studies for each of five prostate patients. Each CT was contoured by three experienced radiation oncologists. For each patient, one CT was designated the source image and the other two were target images. A deformable image registration process was used to register each source CT to each target CT and then transfer the manually drawn treatment planning contours from the source CT to the target CTs. The accuracy of the automatically transferred contours (and thus of the deformable registration process) was assessed by comparing them to the manual contours on the target CTs, with the differences evaluated with respect to interobserver variability in the manual contours. Then each of the target CTs was modified to include increased noise characteristic of cone‐beam CT and the tests were repeated. Changes in registration accuracy due to increased noise were detected by monitoring changes in the automatically transferred contours. Results: We found that the additional noise caused no significant loss of registration accuracy at magnitudes that exceeded what would normally be found in an actual cone‐beam CT. Summary: We conclude that noise levels in cone‐beam CTs that might reduce manual contouring accuracy do not reduce image registration and automatic contouring accuracy.
Patient dosimetry for hybrid MRI‐radiotherapy systems
Authors: Kirkby C. , Stanescu T. , Rathee S. , Carlone M. , Murray B. , Fallone B. G.
Published: March 2008

A novel geometry has been proposed for a hybrid magnetic resonance imaging (MRI)‐linac system in which a 6 MV linac is mounted on the open end of a biplanar, low field (0.2 T) MRI magnet on a single gantry that is free to rotate around the patient. This geometry creates a scenario in which the magnetic field vector remains fixed with respect to the incident photon beam, but moves with respect to the patient as the gantry rotates. Other proposed geometries are characterized by a radiation source rotating about a fixed cylindrical magnet where the magnetic field vector remains fixed with respect to the patient. In this investigation we simulate the inherent dose distribution patterns within the two MRI‐radiation source geometries using PENELOPE and EGSnrc Monte Carlo radiation transport codes with algorithms implemented to account for the magnetic field deflection of charged particles. Simulations are performed in phantoms and for clinically realistic situations. The novel geometry results in a net Lorentz force that remains fixed with respect to the patient (in the cranial‐caudal direction) and results in a cumulative influence on dose distribution for a multiple beam treatment scenario. For a case where patient anatomy is reasonably homogeneous (brain plan), differences in dose compared to a conventional (no magnetic field) case are minimal for the novel geometry. In the case of a lung plan where the inhomogeneous patient anatomy allows for the magnetic field to have significant influence on charged particle transport, larger differences occur in a predictable manner. For a system using a fixed cylindrical geometry and higher magnetic field (1.5 T), differences from the case without a magnetic field are significantly greater.
Correction of megavoltage cone‐beam CT images for dose calculation in the head and neck region
Authors: Aubry Jean‐François , Pouliot Jean , Beaulieu Luc
Published: March 2008

Megavoltage cone‐beam computed tomography (MVCBCT) imaging systems are now available for image‐guided radiation therapy delivery and verification. In order to use the three‐dimensional anatomical information for dose calculation, the MVCBCT image must provide accurate electron density. This work proposes a new method that has been developed to correct for the cupping and missing data artifacts seen on MVCBCT images of the head and neck region. It uses a conventional kilovoltage CT (kVCT) image as a reference for electron density and rigid registration with a MVCBCT image to obtain correction factors. Dose calculations performed on MVCBCT images corrected with the proposed method agree with calculations done on kVCT images within on phantoms. With patients images the agreement is within above the shoulders and below the shoulder line. This level of dose calculation accuracy allows the use of MVCBCT images for dose verification purposes.
Digital radiography using amorphous selenium: Photoconductively activated switch (PAS) readout system
Authors: Reznik Nikita , Komljenovic Philip T. , Germann Stephen , Rowlands John A.
Published: March 2008

A new amorphous selenium digital radiography detector is introduced. The proposed detector generates a charge image in the layer in a conventional manner, which is stored on electrode pixels at the surface of the layer. A novel method, called photoconductively activated switch (PAS), is used to read out the latent x‐ray charge image. The PAS readout method uses lateral photoconduction at the surface which is a revolutionary modification of the bulk photoinduced discharge (PID) methods. The PAS method addresses and eliminates the fundamental weaknesses of the PID methods—long readout times and high readout noise—while maintaining the structural simplicity and high resolution for which PID optical readout systems are noted. The photoconduction properties of the surface were investigated and the geometrical design for the electrode pixels for a PAS radiography system was determined. This design was implemented in a single pixel PAS evaluation system. The results show that the PAS x‐ray induced output charge signal was reproducible and depended linearly on the x‐ray exposure in the diagnostic exposure range. Furthermore, the readout was reasonably rapid ( for pixel discharge). The proposed detector allows readout of half a pixel row at a time (odd pixels followed by even pixels), thus permitting the readout of a complete image in for a detector with the potential of reducing that time by using greater readout light intensity. This demonstrates that based x‐ray detectors using photoconductively activated switches could form a basis for a practical integrated digital radiography system.