A Cyclotron Decommissioning Radiological Assessment Exercise Performed by Student Mentees Underrepresented in the Radiation Safety Profession.

Cyclotrons used in nuclear medicine imaging accelerate protons, deuterons, and helium ions to bombard a target, which produces nuclear reactions that generate positron-emitting radionuclides. Secondary neutrons are nonuniformly emitted in these reactions and induce heterogeneous activation of the cyclotron components and concrete vault enclosure. This poses radioactive waste management complications when decommissioning a cyclotron facility, since the objective is to ensure that exposures are within regulatory limits and as low as reasonably achievable (ALARA). The McGovern Medical School in The University of Texas Health Science Center in Houston housed a Scanditronix MC40 cyclotron that produced short-lived radioisotopes for Positron Emission Tomography (PET) imaging from 1984 to 2001 until Tropical Storm Allison rendered it inoperable. The purpose of this study was to provide underrepresented Science, Technology, Engineering and Mathematics (STEM) students an ALARA experience with a practical problem encountered in the radiation safety profession. Gamma dose rate measurements were performed with both a Mirion InSpector 1000 spectrometer and Fluke 451P survey meter in the vault at locations identified as hotspots based on preliminary scoping surveys with the Ludlum model 44-9 detector. However, gamma spectra were measured with the spectrometer exclusively at hotspots along the west wall. Results indicated the maximum gamma dose rate of 129 ± 31 nSv h was about 2 times background near the central beam transport line of the now inoperable cyclotron. Furthermore, gamma emission peaks were identified in the spectra from trace amounts of Co and Eu in the vault's concrete walls.

Contextual Information for the Potential Enhancement of Annual Radiation Protection Program Review Reports.

Organizations possessing sources of ionizing radiation are required to develop, document, and implement a "radiation protection program" that is commensurate with the scope and extent of permitted activities and sufficient to ensure compliance with basic radiation safety regulations. The radiation protection program must also be reviewed at least annually, assessing program content and implementation. A convenience sample assessment of web-accessible and voluntarily-submitted radiation protection program annual review reports revealed that while the reports consistently documented compliance with necessary regulatory elements, very few included any critical contextual information describing how important the ability to possess radiation sources was to the central mission of the organization. Information regarding how much radioactive material was currently possessed as compared to license limits was also missing. Summarized here are suggested contextual elements that can be considered for possible inclusion in annual radiation protection program reviews to enhance stakeholder understanding and appreciation of the importance of the ability to possess radiation sources and the importance of maintaining compliance with associated regulatory requirements.

Radiation Monitoring Results from the First Year of Operation of a Unique Ambulance-based Computed Tomography Unit for the Improved Diagnosis and Treatment of Stroke Patients.

When a blood clot blocks the blood supply to the brain or when a blood vessel bursts, resulting in brain cell death, the medical condition is referred to as a "stroke." Stroke is a main cause of death worldwide and is a common cause of disability. A common form of stroke, called ischemic stroke, is when blood flow to the brain is decreased. Clinical research has revealed that treatment within the very first hours of symptom onset is key for ischemic stroke with recanalization of occluded arteries by thrombolysis with alteplase. Computed tomography (CT) is one of the diagnostic tools used to determine if this treatment path is appropriate. To determine if health outcomes of possible stroke patients can be improved by decreasing the time from symptom presentation to treatment, the first mobile stroke ambulance unit in the United States was deployed by The University of Texas Health Science Center at Houston (UTHealth) in 2014, equipped with a computed tomography imaging system. The mobile stroke unit shortens the time to treatment for stroke patients by allowing pre-hospital treatment. Having completed its first year of operation, radiation-monitoring data describing the doses delivered to various entities have been characterized. The CT operator's cumulative deep dose equivalent for 1 y of operation was 1.14 mSv resulting from the care of 106 patients. Area monitors were deployed and measurements performed demonstrating that general public doses did not exceed 0.02 mSv h⁻¹ or 1.0 mSv year.

Strategies for Navigating Common Ethical Dilemmas Encountered by Operational Radiation Safety Professionals.

Because operational radiation safety professionals can encounter ethical dilemmas in the course of their work, codes of ethics and professional standards of conduct are maintained by the Health Physics Society (HPS) and the American Academy of Health Physics (AAHP). While these works provide valuable guidance, they do not operationalize the types of ethical dilemmas radiation safety practitioners might encounter. For example, consider the ethical conundrum of "dual loyalty," defined as the situation in which an individual holds simultaneous obligations to two or more parties. In the case of radiation safety, practicing professionals hold obligations to the workers being protected and to the leaders of the organization. If these obligations are in conflict, serious difficulties can arise. The conundrum of dual loyalty is described and a strategy for reducing its effect is discussed. Two other common ethical issues; "confidentiality" and "organizational dissent" are similarly presented. A foundation from which to launch an ongoing dialogue about ethical issues within the radiation safety profession is also proposed.

Characterization of a sialate-O-acetylesterase (NanS) from the oral pathogen Tannerella forsythia that enhances sialic acid release by NanH, its cognate sialidase.

Tannerella forsythia, a Gram-negative member of the Bacteroidetes has evolved to harvest and utilize sialic acid. The most common sialic acid in humans is a mono-N-acetylated version termed Neu5Ac (5-N-acetyl-neuraminic acid). Many bacteria are known to access sialic acid using sialidase enzymes. However, in humans a high proportion of sialic acid contains a second acetyl group attached via an O-group, i.e. chiefly O-acetylated Neu5,9Ac2 or Neu5,4Ac2. This diacetylated sialic acid is not cleaved efficiently by many sialidases and in order to access diacetylated sialic acid, some organisms produce sialate-O-acetylesterases that catalyse the removal of the second acetyl group. In the present study, we performed bioinformatic and biochemical characterization of a putative sialate-O-acetylesterase from T. forsythia (NanS), which contains two putative SGNH-hydrolase domains related to sialate-O-acetylesterases from a range of organisms. Purification of recombinant NanS revealed an esterase that has activity against Neu5,9Ac2 and its glycolyl form Neu5Gc,9Ac. Importantly, the enzyme did not remove acetyl groups positioned at the 4-O position (Neu5,4Ac2). In addition NanS can act upon complex N-glycans released from a glycoprotein [erythropoietin (EPO)], bovine submaxillary mucin and oral epithelial cell-bound glycans. When incubated with its cognate sialidase, NanS increased sialic acid release from mucin and oral epithelial cell surfaces, implying that this esterase improves sialic acid harvesting for this pathogen and potentially other members of the oral microbiome. In summary, we have characterized a novel sialate-O-acetylesterase that contributes to the sialobiology of this important human pathogen and has potential applications in the analysis of sialic acid diacetylation of biologics in the pharmaceutical industry.

Maternal occupational exposure to ionizing radiation and major structural birth defects.

BACKGROUND: Ionizing radiation (IR) is known to be carcinogenic and mutagenic, but little is known about the association between maternal occupational exposure to IR and birth defects. METHODS: We studied 38,009 mothers who participated in the National Birth Defects Prevention Study and delivered between 1997 and 2009. We assessed odds ratios [ORs] for the association between maternal occupations with potential exposure to IR and 39 birth defects. RESULTS: We observed significant odds ratios (ORs) for isolated hydrocephaly (adjusted OR [AOR], 2.1; 95% confidence interval [CI], 1.1-4.2), isolated anotia/microtia (AOR, 2.0; 95% CI, 1.0-4.0), isolated colonic atresia (crude OR, 7.5; 95% CI, 2.5-22.3), isolated omphalocele (AOR, 2.3; 95% CI, 1.1-4.6) and isolated anencephaly (crude OR, 0.23; 95% CI, 0.06-0.94). We also observed a nonsignificant OR for birth defects in aggregate (AOR, 2.0; 95% CI, 0.9-4.6) among mothers with potential occupational exposure to fluoroscopy. CONCLUSION: We assessed 39 birth defects, observing that maternal occupations with potential exposure to IR were associated with a significantly increased risk for 4 birth defects and a significantly protected risk for 1 birth defect. These results should be interpreted cautiously because our measurement of exposure is qualitative, some of these associations may be due to occupational exposures that are correlated with IR and some may be due to chance. However, these findings serve as the first evaluation of these relationships in a large study and may be useful for generating hypotheses for future studies.

Tissue-engineered, hydrogel-based endothelial progenitor cell therapy robustly revascularizes ischemic myocardium and preserves ventricular function.

OBJECTIVES: Cell-based angiogenic therapy for ischemic heart failure has had limited clinical impact, likely related to low cell retention (<1%) and dispersion. We developed a novel, tissue-engineered, hydrogel-based cell-delivery strategy to overcome these limitations and provide prolonged regional retention of myocardial endothelial progenitor cells at high cell dosage. METHODS: Endothelial progenitor cells were isolated from Wistar rats and encapsulated in fibrin gels. In vitro viability was quantified using a fluorescent live-dead stain of transgenic enhanced green fluorescent protein(+) endothelial progenitor cells. Endothelial progenitor cell-laden constructs were implanted onto ischemic rat myocardium in a model of acute myocardial infarction (left anterior descending ligation) for 4 weeks. Intramyocardial cell injection (2 × 10(6) endothelial progenitor cells), empty fibrin, and isolated left anterior descending ligation groups served as controls. Hemodynamics were quantified using echocardiography, Doppler flow analysis, and intraventricular pressure-volume analysis. Vasculogenesis and ventricular geometry were quantified. Endothelial progenitor cell migration was analyzed by using endothelial progenitor cells from transgenic enhanced green fluorescent protein(+) rodents. RESULTS: Endothelial progenitor cells demonstrated an overall 88.7% viability for all matrix and cell conditions investigated after 48 hours. Histologic assessment of 1-week implants demonstrated significant migration of transgenic enhanced green fluorescent protein(+) endothelial progenitor cells from the fibrin matrix to the infarcted myocardium compared with intramyocardial cell injection (28 ± 12.3 cells/high power field vs 2.4 ± 2.1 cells/high power field, P = .0001). We also observed a marked increase in vasculogenesis at the implant site. Significant improvements in ventricular hemodynamics and geometry were present after endothelial progenitor cell-hydrogel therapy compared with control. CONCLUSIONS: We present a tissue-engineered, hydrogel-based endothelial progenitor cell-mediated therapy to enhance cell delivery, cell retention, vasculogenesis, and preservation of myocardial structure and function.

An updated radiation protection program prospectus based on 20 years of data describing program drivers and activities.

In 1992, the University of Texas Health Science Center at Houston (UTHSCH) Radiation Safety Program began assembling data on a monthly basis that described various program drivers and associated activities. At the end of calendar year 2002, a decade of data had been collected, so the information was summarized into a novel program prospectus, displaying various program indicator parameters in a format similar to that used in a commercial enterprise prospectus provided to potential investors. The consistent formatting of the data afforded a succinct and easily digestible snapshot of program activities and trends. Feedback from various program stakeholders, even those unfamiliar with radiation safety matters, was overwhelmingly positive. By the end of 2012, a total of 20 years of data had been collected, so an updated and slightly modified prospectus was created. The summary document has helped to describe the drivers of the program, revealed some interesting trends, and has aided in maintaining program support even in challenging economic times. The data summary has also proved to be useful in making future projections regarding program needs.

Situational photographic postings for enhancing the proper operation of infrequently utilized x-ray devices.

Radiation safety surveillance activities conducted at The University of Texas Health Science Center at Houston indicated that x-ray devices were not being operated properly in settings where the device was used infrequently and where there were high demands of other job responsibilities. This situation was considered to be a possible precursor to the delivery of unnecessary dose to patients and workers and poor diagnostic image quality. To enhance the proper operation of such devices, photographic reminders customized for each use setting were created and posted in the rooms near the x-ray equipment. Each poster consisted of operators and patients exhibiting proper techniques while using appropriate protective equipment. The photographs were captured digitally and then augmented with brief informational textboxes that highlighted key aspects. Verbal feedback from the user community after reviewing these simple images has been very positive, as many operators indicated that work demands impacted their ability to thoroughly reread instrument operating manuals prior to use. Therefore, the capturing of a simple situational photograph inclusive of the persons actually using the unit can serve as a powerful reminder of the desired and safe means of collecting quality x-ray images while avoiding unnecessary radiological exposure to health care professionals and patients.

A radiation protection program prospectus based on the collection of 10 years of key performance indicator data.

In 1992, the University of Texas Health Science Center at Houston Radiation Safety Program began assembling data on a monthly basis that described various program activities. At the end of calendar year 2002, a decade of data had been collected, so the information was summarized into a novel program prospectus, displaying various indicator parameters in a format similar to that used in a commercial enterprise prospectus provided to potential investors. The consistent formatting of the data afforded a succinct and easily digestible snapshot of program activities and trends. Feedback from various program stakeholders, even those unschooled in radiation safety matters, was overwhelmingly positive. The prospectus aided in communicating the scope of work undertaken by the program, and has helped maintain program support, even in challenging economic times. The data summary is also proving to be useful in making future projections regarding program needs.

An initial radiation safety needs assessment of Costa Rica: the South Texas Chapter of the Health Physics Society's strategic planning appraisal for participation in the "Radiation Safety Without Borders" initiative.

In response to the Health Physics Society's recent 'radiation safety without borders" initiative, the South Texas Chapter of the Health Physics Society selected Costa Rica as its partner country of choice. To develop an understanding of the radiation safety needs of this country, the fall 2001 University of Texas Health Science Center at Houston School of Public Health Environmental Radiation and Radioactivity class was tasked with the assignment of assessing the possible radiation safety needs and concerns for this country. The assignment culminated in a class presentation to the membership of the South Texas Chapter during its annual fall meeting. Using library and web based resources, tile students reviewed a number of public health and radiation-related topics. Life expectancies were found to be equivalent to the United States, even though significant differences in per capita health expenditures were noted. Costa Rica exhibited lower population mortality rates from major causes such as cardiovascular diseases, neoplasms, and external sources. Maternal and infant mortality rates were found to be much higher in Costa Rica than in the United States. Naturally occurring radiation sources such as uranium deposits were not identified as apparent major radiation issues of concern, although ultraviolet radiation exposures are consistently high. Several recent events in the country and the region involving patient overexposures suggest that concerns are likely focused on ensuring the proper use and maintenance of healing arts radiation equipment. The lack of available information on radioactive waste disposal suggests that waste handling also may be an issue warranting attention. The exercise proved to be very educational for the students, and the information gathered will serve to focus the Chapter's efforts when technical exchanges are initiated. The importance of linking this initiative to other existing programs within the country is also discussed.

Piloting a new radiation protection program strategy: rewarding compliance rather than sanctioning non-compliance.

In an attempt to improve compliance with historically problematic radiation protection program requirements, a novel incentive program was created in cooperation with a major vendor of biomedical research products. Researchers using radioisotopes that placed orders from a partnering vendor were afforded an added price discount if verified by the institutional radiation safety program to be in compliance with laboratory contamination survey requirements. The program, piloted for a period of 1 y, resulted in a total institutional savings of approximately $2,200 and a 27% improvement in compliance with targeted objectives when compared with previous years. Feedback from pilot participants was extremely positive, as the program served to shift the perception of the radiation protection program from one that sanctions non-compliance to one that rewards compliance. The relative success of the pilot program suggests that the approach may be broadly applicable both within radiation safety programs and other safety-related settings as well.