Case Studies of Fraud Associated with the Use of Radiation Sources: Practical Avoidance Strategies Based on Lessons Learned

ABSTRACT

Periodically the radiation protection profession has experienced purposeful deception practices that remained undetected for some time. Upon discovery, the cases of fraud revealed gaps in confirmation or validation practices that the radiation protection community should note. Summarized here is a convenience sample of actual cases of fraud involving radiation sources along with the exploited process vulnerabilities. Recommended process improvements that the radiation safety community may consider are presented to improve the collective fidelity of radiation protection processes.

Practical Considerations for Navigating Withdrawal from the Federal Select Agent Program

Introduction

Clear guidance is provided by the Federal Select Agent Program (FSAP) to assist registered entities in nearly all facets of compliance with the Federal select agent regulations (7 CFR Part 331; 9 CFR Part 121; 42 CFR Part 73). If a registered entity chooses to discontinue its registration, detailed instructions for registration withdrawal are deeply embedded within a document entitled "eFSAP Form 1 Amendment Instructions," which is found on the FSAP website within the electronic Federal Select Agent Program (eFSAP) Resource Center.

Methods

Using the information found within the eFSAP Form 1 Amendment Instructions, as well as extensive written and verbal guidance provided by the lead assigned entity point of contact at the FSAP, we completed the FSAP withdrawal process during a 12-month period between 2022 and 2023.

Discussion

This commentary shares our recent professional experiences navigating the FSAP withdrawal process at the University of Texas Health Science Center at Houston (UTHealth Houston). Successes, challenges, and lessons learned are shared so that others planning or considering withdrawing may benefit from our experience.

Conclusion

The resources provided for withdrawal within the eFSAP Form 1 Amendment Instructions are relatively basic, and additional details are not currently found in other FSAP guidance documents. Therefore, direct communication and support from the FSAP to the entity Responsible Officials are imperative to ensure a safe, secure, and compliant withdrawal.

A Means of Codifying Safety Cross-Training Knowledge Expectations for Biosafety Professionals

Introduction

The health and safety issues encountered by biosafety professionals in the daily conduct of their work is rarely limited solely to potentially infectious pathogens. A basic understanding of the other types of hazards inherent to laboratories is necessary. As such, management of the health and safety program at an academic health institution sought to ensure crosscutting competency for its technical staff, including staff members within the biosafety program.

Methods

Using a focus group approach, a team of safety professionals from a variety of specialties developed a list of 50 basic health and safety items that any safety specialist should know, inclusive of basic but important information about biosafety that was considered imperative for staff members to understand. This list was used as the basis for a formal cross-training effort.

Results

Staff responded positively to the approach and the associated cross-training, and overall compliance with an array of health and safety expectations was experienced across the institution. Subsequently, the list of questions has been shared broadly with other organizations for their own consideration and use.

Discussion/Conclusion

The codification of the basic knowledge expectations for technical staff within a health and safety program at an academic health institution, which includes the biosafety program technical staff, was warmly received and helped establish what information was expected to be known and what issues warranted input from other specialty areas. The cross-training expectations served to expand the health and safety services provided despite resource limitations and organizational growth.

Considerations for Radiation Safety Professionals to Prepare and Respond to the Next Pandemic

ABSTRACT

The Health Physics Society's stated mission is "excellence in the science and practice of radiation safety." Why, then, should we discuss disease outbreaks, epidemics, and pandemics with radiation safety professionals? The answer is simple: all workers are impacted by infectious diseases-and, as safety professionals, we will inevitably be called upon to prepare for and respond to these events. The COVID-19 pandemic has disrupted every facet of life, including home, school, work, and leisure. Moreover, virtually all radiation safety professionals have been impacted by the pandemic either personally, academically, or professionally. Even if radiation safety professionals were not involved directly with COVID-19 response, they were impacted by school closures, remote schooling and work, testing regimes, temperature screenings, vaccination programs, and so forth. However, many radiation safety professionals have been intimately involved in COVID-19 response through activities such as the deployment of personal protective equipment, directional airflow verification for isolation areas, disinfection and decontamination efforts, the design and layout of testing and vaccine centers, and in many other ways. Yet, it is likely that many radiation safety professionals have not received formal training in epidemiology, disease control, or other related topics, and thus may not be attuned to the key aspects to consider when the next pandemic emerges-and it will.

Basic Cyber Security Considerations for Licensees of Radioactive Materials and Registrants of Radiation Producing Devices in an Era of Remote or Hybrid Compliance Inspections

ABSTRACT

The onset of the COVID pandemic impacted various regulatory agencies' ability to safely fulfill their regulatory compliance inspection mandates via on-site inspections. Some agencies shifted to a remote or hybrid inspection process, which necessitates the electronic transmittal of a variety of records that may or may not have been transmitted in this fashion in the past, raising concerns about the records being sent and received securely. Considering this new environment, some basic cyber security diagnostic considerations are described for radiation source permit holders to consider prior to responding to an apparent legitimate regulatory inspection request, both in the current COVID cyber risk environment and the environment likely to exist into the future.

Pivoting the Biosafety Program in Response to COVID-19: Recommendations of Key Services and Tasks to Consider for the Next Pandemic

Introduction

With the onset of the COVID-19 pandemic, a rapid adjustment of work tasks was necessary for many biosafety programs (and other safety programs) to address drastic shifts in workload demands amid pandemic-related shutdowns and subsequent needs for supporting COVID-19-related safe work protocols, diagnostic testing, research, vaccine development, and so forth. From a program management standpoint, evaluating and understanding these tasks were critically important to ensure that appropriate support and resources were in place, especially during such unprecedented times of rapid change and significant impact to normal life and routine.

Methods

Described here are examples of how the biosafety program at The University of Texas Health Science Center at Houston (UTHealth Houston) addressed these challenges.

Results

As part of this required pivot, key services and tasks emerged into three distinct categories: (1) those that were temporarily diminished, (2) those that had to continue despite COVID-19 and the associated shutdowns for safety or compliance purposes, and (3) those that dramatically increased in volume, frequency, and novelty.

Conclusion

Although the adjustments described were made in situ as the pandemic evolved, the cataloging of these tasks throughout the experience can serve as a template for biosafety programs to plan and prepare for the next pandemic, which will inevitably occur.

Assessing the Established Competency Categories of the Biosafety, Infection Prevention, and Public Health Professions: A Guide for Addressing Needed Professional Development Training for the Current and Next Pandemic

A recent series of widespread infectious disease outbreaks has highlighted commonalities and differences between three key professions that operate on the front lines of response in support of research and/or direct healthcare providers: biosafety, infection prevention, and public health. This assessment, which builds upon previous study by the authors, examines the stated professional competency categories for these three areas, highlighting similarities and differences. This assessment is important as these professions are being drawn together in an operational environment driven by the current pandemic and inevitably future disease outbreaks. Cross-training opportunities for the various professions are proposed.

A 30-Year Radiation Safety Prospectus Describing Organizational Drivers, Program Activities, and Outcomes

ABSTRACT

In 1992, the University of Texas Health Science Center at Houston (UTHealth) Radiation Safety Program began assembling data on a monthly basis that described various program drivers and associated activities. A summary of the data was assembled on an annual basis and shared with the professional health physics community at the 10-y and 20-y intervals. With the inclusion of 1991 data points, three decades (1991 to 2020) of data have now been collected and summarized into an updated program prospectus. The prospectus models a commercial enterprise prospectus provided to potential investors and displays various program indicator parameters. The consistent formatting of the data affords an easily digestible and succinct snapshot of program activities and trends. Various program stakeholder's feedback regarding this data continues to be well received. Additionally, UTHealth provides increasing support for UT Physicians clinics throughout the greater Houston, Texas area. The prospectus allows succinct description of the drivers of the program, revealed interesting trends, and has identified training needs for both existing personnel and academic programs that support the radiation protection sciences.

An assessment of outpatient clinic room ventilation systems and possible relationship to disease transmission

BACKGROUND

With healthcare shifting to the outpatient setting, this study examined whether outpatient clinics operating in business occupancy settings were conducting procedures in rooms with ventilation rates above, at, or below thresholds defined in the American National Standards Institute/American Society of Heating, Refrigerating and Air-Conditioning Engineers/American Society for Health Care Engineering Standard 170 for Ventilation in Health Care Facilities and whether lower ventilation rates and building characteristics increase the risk of disease transmission.

METHODS

Ventilation rates were measured in 105 outpatient clinic rooms categorized by services rendered. Building characteristics were evaluated as determinants of ventilation rates, and risk of disease transmission was estimated using the Gammaitoni-Nucci model.

RESULTS

When compared to Standard 170, 10% of clinic rooms assessed did not meet the minimum requirement for general exam rooms, 39% did not meet the requirement for treatment rooms, 83% did not meet the requirement for aerosol-generating procedures, and 88% did not meet the requirement for procedure rooms or minor surgical procedures.

CONCLUSIONS

Lower than standard air changes per hour were observed and could lead to an increased risk of spread of diseases when conducting advanced procedures and evaluating persons of interest for emerging infectious diseases. These findings are pertinent during the SARS-CoV-2 pandemic, as working guidelines are established for the healthcare community.

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.

NIST Interlaboratory Study on Glycosylation Analysis of Monoclonal Antibodies: Comparison of Results from Diverse Analytical Methods

Glycosylation is a topic of intense current interest in the development of biopharmaceuticals because it is related to drug safety and efficacy. This work describes results of an interlaboratory study on the glycosylation of the Primary Sample (PS) of NISTmAb, a monoclonal antibody reference material. Seventy-six laboratories from industry, university, research, government, and hospital sectors in Europe, North America, Asia, and Australia submitted a total of 103 reports on glycan distributions. The principal objective of this study was to report and compare results for the full range of analytical methods presently used in the glycosylation analysis of mAbs. Therefore, participation was unrestricted, with laboratories choosing their own measurement techniques. Protein glycosylation was determined in various ways, including at the level of intact mAb, protein fragments, glycopeptides, or released glycans, using a wide variety of methods for derivatization, separation, identification, and quantification. Consequently, the diversity of results was enormous, with the number of glycan compositions identified by each laboratory ranging from 4 to 48. In total, one hundred sixteen glycan compositions were reported, of which 57 compositions could be assigned consensus abundance values. These consensus medians provide community-derived values for NISTmAb PS. Agreement with the consensus medians did not depend on the specific method or laboratory type. The study provides a view of the current state-of-the-art for biologic glycosylation measurement and suggests a clear need for harmonization of glycosylation analysis methods.

A Pilot Examination of the Methods Used to Counteract Insider Threat Security Risks Associated with the Use of Radioactive Materials in the Research and Clinical Setting

While many organizations maintain multiple layers of security control methodologies to prevent outsiders from gaining unauthorized access, persons such as employees or contractors who have been granted legitimate access can represent an "insider threat" risk. Interestingly, some of the most notable radiological events involving the purposeful contamination or exposure of individuals appear to have been perpetrated by insiders. In the academic and medical settings, radiation safety professionals focus their security efforts on (1) ensuring controls are in place to prevent unauthorized access or removal of sources, and (2) increasing security controls for the unescorted accessing of large sources of radioactivity (known as "quantities of concern"). But these controls may not completely address the threat insiders represent when radioactive materials below these quantities are present. The goal of this research project was to characterize the methodologies currently employed to counteract the insider security threat for the misuse or purposeful divergence of radioactive materials used in the academic and medical settings. A web-based survey was used to assess how practicing radiation safety professionals in academic and medical settings anticipate, evaluate, and control insider threat security risks within their institutions. While all respondents indicated that radioactive sources are being used in amounts below quantities of concern, only 6 % consider insider threat security issues as part of the protocol review for the use of general radioactive materials. The results of this survey identify several opportunities for improvement for institutions to address security gaps.

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.

Maternal exposure to radiographic exams and major structural birth defects

BACKGROUND

An increasing number of radiologic exams are performed in the United States, but very few studies have examined the effects of maternal exposure to radiologic exams during the periconceptional period and birth defects.

OBJECTIVES

To assess the association between maternal exposure to radiologic exams during the periconceptional period and 19 categories of birth defects using a large population-based study of birth defects.

METHODS

We studied 27,809 case mothers and 10,200 control mothers who participated in the National Birth Defects Prevention Study and delivered between 1997 and 2009. Maternal exposure to radiologic exams that delivered ionizing radiation to the urinary tract, lumbar spine, abdomen, or pelvis were identified based on the mother's report of type of radiologic exams, organ or body part scanned and the month during which the exam occurred

RESULTS

Overall, 0.9% of mothers reported exposure to one of these types of radiographic exams during the periconceptional period. We observed significant associations between maternal exposure during the first trimester and isolated Dandy-Walker malformation (odds ratio = 7.7; 95% confidence interval, 1.8-33) and isolated d-transposition of the great arteries (odds ratio = 3.8; 95% confidence interval, 1.4-10.3). However, the result for isolated Dandy-Walker malformation was based on only two exposed cases.

CONCLUSION

These results should be interpreted cautiously because multiple statistical tests were conducted and measurements of exposure were based on maternal report. However, our results may be useful for generating hypotheses for future studies. Birth Defects Research (Part A) 106:563-572, 2016. © 2016 Wiley Periodicals, Inc.

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.

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.

Local origins impart conserved bone type-related differences in human osteoblast behaviour

Osteogenic behaviour of osteoblasts from trabecular, cortical and subchondral bone were examined to determine any bone type-selective differences in samples from both osteoarthritic (OA) and osteoporotic (OP) patients. Cell growth, differentiation; alkaline phosphatase (TNAP) mRNA and activity, Runt-related transcription factor-2 (RUNX2), SP7-transcription factor (SP7), bone sialoprotein-II (BSP-II), osteocalcin/bone gamma-carboxyglutamate (BGLAP), osteoprotegerin (OPG, TNFRSF11B), receptor activator of nuclear factor-κβ ligand (RANKL, TNFSF11) mRNA levels and proangiogenic vascular endothelial growth factor-A (VEGF-A) mRNA and protein release were assessed in osteoblasts from paired humeral head samples from age-matched, human OA/OP (n = 5/4) patients. Initial outgrowth and increase in cell number were significantly faster (p < 0.01) in subchondral and cortical than trabecular osteoblasts, in OA and OP, and this bone type-related differences were conserved despite consistently faster growth in OA. RUNX2/SP7 levels and TNAP mRNA and protein activity were, however, greater in trabecular than subchondral and cortical osteoblasts in OA and OP. BSP-II levels were significantly greater in trabecular and lowest in cortical osteoblasts in both OA and OP. In contrast, BGLAP levels showed divergent bone type-selective behaviour; highest in osteoblasts from subchondral origins in OA and trabecular origins in OP. We found virtually identical bone type-related differences, however, in TNFRSF11B:TNFSF11 in OA and OP, consistent with greater potential for paracrine effects on osteoclasts in trabecular osteoblasts. Subchondral osteoblasts (OA) exhibited highest VEGF-A mRNA levels and release. Our data indicate that human osteoblasts in trabecular, subchondral and cortical bone have inherent, programmed diversity, with specific bone type-related differences in growth, differentiation and pro-angiogenic potential in vitro.

Assessing the Biological Safety Profession's Evaluation and Control of Risks Associated with the Field Collection of Potentially Infectious Specimens

Because the origins of the biological safety profession are rooted in the control and prevention of laboratory-associated infections, the vocation focuses primarily on the safe handling of specimens within the laboratory. But in many cases, the specimens and samples handled in the lab are originally collected in the field where a broader set of possible exposure considerations may be present, each with varying degrees of controllability. The failure to adequately control the risks associated with collecting biological specimens in the field may result in illness or injury, and could have a direct impact on laboratory safety, if infectious specimens were packaged or transported inappropriately, for example. This study developed a web-based survey distributed to practicing biological safety professionals to determine the prevalence of and extent to which biological safety programs consider and evaluate field collection activities. In cases where such issues were considered, the data collected characterize the types of controls and methods of oversight at the institutional level that are employed. Sixty-one percent (61%) of the survey respondents indicated that research involving the field collection of biological specimens is conducted at their institutions. A majority (79%) of these field collection activities occur at academic institutions. Twenty-seven percent (27%) of respondents indicated that their safety committees do not consider issues related to biological specimens collected in the field, and only 25% with an oversight committee charged to review field collection protocols have generated a field research-specific risk assessment form to facilitate the assembly of pertinent information for a project risk assessment review. The results also indicated that most biosafety professionals (73% overall; 71% from institutions conducting field collection activities) have not been formally trained on the topic, but many (64% overall; 87% from institutions conducting field collection activities) indicated that training on field research safety issues would be helpful, and even more (71% overall; 93% from institutions conducting field collection activities) would consider participation in such a training course. Results obtained from this study can be used to develop a field research safety toolkit and associated training curricula specifically targeted to biological safety professionals.

A data-driven model for estimating industry average numbers of hospital security staff

In this article the authors report the results of an expanded survey, financed by the International Healthcare Security and Safety Foundation (IHSSF), applied to the development of a model for determining the number of security officers required by a hospital.

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.

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.

How the University of Texas system responded to the need for interim storage of low-level radioactive waste materials

Faced with the prospect of being unable to permanently dispose of low-level radioactive wastes (LLRW) generated from teaching, research, and patient care activities, component institutions of the University of Texas System worked collaboratively to create a dedicated interim storage facility to be used until a permanent disposal facility became available. Located in a remote section of West Texas, the University of Texas System Interim Storage Facility (UTSISF) was licensed and put into operation in 1993, and since then has provided safe and secure interim storage for up to 350 drums of dry solid LLRW at any given time. Interim storage capability provided needed relief to component institutions, whose on-site waste facilities could have possibly become overburdened. Experiences gained from the licensing and operation of the site are described, and as a new permanent LLRW disposal facility emerges in Texas, a potential new role for the storage facility as a surge capacity storage site in times of natural disasters and emergencies is also discussed.

Staffing benchmarks: a model for determining how many security officers are enough

The authors describe the development of a model which assists with answering the question, "for a facility with certain characteristics, what would be the industry average number of security FTE's?" Through the use of multiple regression analysis using actual field data, an objective means of making this determination is possible, they report.

Surge capacity volunteer perspectives on a field training exercise specifically designed to emphasize likely roles during a disaster response

Experience gained from involvement in a number of emergency response activities since September 2001 in Texas indicated that the likely roles of statewide medical reserve corps units typically included aspects such as crowd control, registration and tracking, and information management. The need for training specifically focused on these likely roles became apparent. A novel field training exercise was developed that specifically focused on these likely roles. The exercise centered on a scenario involving the surreptitious placement of radioactivity in high traffic areas across the country, resulting in the contamination of large numbers of individuals. Because the source of the contamination was unknown, surge capacity contamination screening and data collection centers became necessary. Feedback collected from drill participants was measured to be overwhelmingly positive, with the vast majority of participants indicating a marked improvement in their understanding of their likely roles in a disaster of this type. The approach used in this training effort may be of use to other disaster surge capacity organizations as part of their strategic planning efforts as a means of ensuring that individuals involved in response activities possess familiarity with their likely roles during a wide scale public health disaster event.

Risk communication considerations to facilitate the screening of mass populations for potential contamination with radioactive material

Experience gained during a field training exercise with a Medical Reserve Corps unit on the screening of large groups of individuals for possible contamination with radioactive material revealed that while exercise participants were generally attentive to the proper use of protective equipment and detectors, they tended to overlook important basic risk communications aspects. For example, drill participants did not actively communicate with the persons waiting in line for screening, a step which would provide re-assurance, possibly minimize apprehension, and would clarify expectations. When questioned on this issue of risk communication, drill participants were often able to craft ad hoc messages, but the messages were inconsistent and likely would not have significantly helped diminish anxiety and maintain crowd control. Similar difficulties were encountered regarding messaging for persons determined to be contaminated, those departing the screening center, and those to be delivered to the media. Based on these experiences, the need for a suggested list of risk communication points was identified. To address this need, a set of risk communication templates were developed that focused on the issues likely to be encountered in a mass screening event. The points include issues such as the importance of remaining calm, steps for minimizing possible intake or uptake, considerations for those exhibiting acute injuries, expected screening wait times, the process to be followed and the information to be collected, the process to be undertaken for those exhibiting contamination, and symptoms to watch for after departure. Drill participants indicated in follow-up discussions that such pre-established risk communication templates would serve to enhance their ability to assist in times of emergency and noted the potential broader applicably of the approach for use in responses for other disasters types as well.

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.

Validation of orthopaedic bench models for trauma surgery

The aim of this study was to validate the use of three models of fracture fixation in the assessment of technical skills. We recruited 21 subjects (six experts, seven intermediates, and eight novices) to perform three procedures: application of a dynamic compression plate on a cadaver porcine model, insertion of an unreamed tibial intramedullary nail, and application of a forearm external fixator, both on synthetic bone models. The primary outcome measures were the Objective Structural Assessment of technical skills global rating scale on video recordings of the procedures which were scored by two independent expert observers, and the hand movements of the surgeons which were analysed using the Imperial College Surgical Assessment Device. The video scores were significantly different for the three groups in all three procedures (p < 0.05), with excellent inter-rater reliability (alpha = 0.88). The novice and intermediate groups specifically were significantly different in their performance with dynamic compression plate and intramedullary nails (p < 0.05). Movement analysis distinguished between the three groups in the dynamic compression plate model, but a ceiling effect was demonstrated in the intramedullary nail and external fixator procedures, where intermediates and experts performed to comparable standards (p > 0.6). A total of 85% (18 of 21) of the subjects found the dynamic compression model and 57% (12 of 21) found all the models acceptable tools of assessment. This study has validated a low-cost, high-fidelity porcine dynamic compression plate model using video rating scores for skills assessment and movement analysis. It has also demonstrated that Synbone models for the application of and intramedullary nail and an external fixator are less sensitive and should be improved for further assessment of surgical skills in trauma. The availability of valid objective tools of assessment of surgical skills allows further studies into improving methods of training.

Identifying the cellular basis for reimplantation failure in repair of the rotator cuff

We examined cultured osteoblasts derived from paired samples from the greater tuberosity and acromion from eight patients with large chronic tears of the rotator cuff. We found that osteoblasts from the tuberosity had no apparent response to mechanical stimulation, whereas those derived from the acromion showed an increase in alkaline phosphatase activity and nitric oxide release which is normally a response of bone cells to mechanical strain. By contrast, we found that cells from both regions were able to respond to dexamethasone, a well-established promoter of osteoblastic differentiation, with the expected increase in alkaline phosphatase activity. Our findings indicate that the failure of repair of the rotator cuff may be due, at least in part, to a compromised capacity for mechanoadaptation within the greater tuberosity. It remains to be seen whether this apparent decrease in the sensitivity of bone cells to mechanical stimulation is the specific consequence of the reduced load-bearing history of the greater tuberosity in these patients.

Developments in shoulder arthroplasty

Indications for shoulder arthroplasty are numerous, mainly owing to glenohumeral osteoarthritis, rheumatoid arthritis, or fracture of the proximal humerus. However, the anatomy and the biomechanics of the shoulder are complex and shoulder arthroplasty has evolved significantly over the past 30 years. This paper presents the main recent evolutions in shoulder replacement, the questions not answered yet, and the main future areas of research. The review focuses firstly on the design, positioning, and fixation of the humeral component, secondly on the design, positioning, and fixation of the glenoid implant, and thirdly on other concepts of shoulder arthroplasty such as the reversed prosthesis, the cementless surface replacement arthroplasty, and the bipolar arthroplasty. This review demonstrates that more research is needed. Although, in the long term, large randomized trials are needed to settle the fundamental questions of what type of replacement and which kind of fixation should be used, biomechanical research in the laboratory should be focused primarily on the comprehension of glenoid loosening, which is a major cause of total shoulder arthroplasty failure, and the significance of radiolucent lines which are often seen but with no clear understanding about their relation with failure.

A security vulnerabilities assessment tool for interim storage facilities of low-level radioactive wastes

Limited permanent low-level radioactive waste (LLRW) disposal capacity and correspondingly high disposal costs have resulted in the creation of numerous interim storage facilities for either decay-in-storage operations or longer term accumulation efforts. These facilities, which may be near the site of waste generation or in distal locations, often were not originally designed for the purpose of LLRW storage, particularly with regard to security. Facility security has become particularly important in light of the domestic terrorist acts of 2001, wherein LLRW, along with many other sources of radioactivity, became recognized commodities to those wishing to create disruption through the purposeful dissemination of radioactive materials. Since some LLRW materials may be in facilities that may exhibit varying degrees of security control sophistication, a security vulnerabilities assessment tool grounded in accepted criminal justice theory and security practice has been developed. The tool, which includes dedicated sections on general security, target hardening, criminalization benefits, and the presence of guardians, can be used by those not formally schooled in the security profession to assess the level of protection afforded to their respective facilities. The tool equips radiation safety practitioners with the ability to methodically and systematically assess the presence or relative status of various facility security aspects, many of which may not be considered by individuals from outside the security profession. For example, radiation safety professionals might not ordinarily consider facility lighting aspects, which is a staple for the security profession since it is widely known that crime disproportionately occurs more frequently at night or in poorly lit circumstances. Likewise, the means and associated time dimensions for detecting inventory discrepancies may not be commonly considered. The tool provides a simple means for radiation safety professionals to assess, and perhaps enhance in a reasonable fashion, the security of their interim storage operations. Aspects of the assessment tool can also be applied to other activities involving the protection of sources of radiation as well.

An analysis of 20 years of radiation-related health care complaints in Texas for the purposes of quality improvement

In an effort to reveal the possible underlying causes of radiation-related health care complaints in the State of Texas, complaint data were evaluated using historical Texas Department of Health-Bureau of Radiation Control (TDH-BRC) reports. A major aim of the study was to generate a summary of the most commonly reported complaints that might be generalized to health care providers using sources of radiation across Texas. A generalizable list of common complaints would be a valuable tool for education and prevention programs, serving to possibly reduce the overall incidence of radiation-related medical complaints. Descriptive text summary reports of complaints were obtained from the TDH-BRC for the 20-y period inclusive of 1981 to 2001. The information was systematically coded into a computerized database. During the 20-y period of study, 481 health care-related complaints were identified, with approximately 74% consisting of claims of an "uncredentialed technician" (39%), "overexposure" (21%), or "regulatory violation" (14%). The most common categories of complaints imply some patient understanding or knowledge of the credentialing requirements of workers, the applicable dose limits, or the regulatory requirements associated with medical procedures. Since it is unlikely that an average patient would be aware of such issues, the findings suggest the complaints are not actually indications of the inappropriate uses of radiation, but are rather based on the patient's broader perception of services rendered. Most of the complaints levied during the period of study were done so anonymously (58%) and were levied against a generic facility (61%) rather than a specific technician (5%), doctor (4%), or student (1%). Approximately 61% of the complaints resulted in the issuance of a notice of violation upon investigation by the TDH-BRC, but the available data did not permit definitive linkage between the initial complaint and the violation issued. Taken in aggregate, the analysis suggests that improved communications between health care providers and the patients they serve could possibly serve to prevent future complaints. Although the analysis was limited to the data from a single state, the results may be of use to quality assurance programs on a broader scale because of the objective identification of likely common issues. Possible options for improving the means of systematically collecting initial compliant data in the future are also discussed.

Reported events of stolen radioactive sources in Texas from 1956 to 2000

Incident reports describing stolen source events in Texas from the years 1956 to 2000 were obtained from the Texas Department of Health-Bureau of Radiation Control and recorded into a computerized database using a pre-established set of codes. The data were then analyzed for the identification and characterization of trends. Over the 45-y period of analysis, 113 sources were reported as stolen. The radionuclides most commonly reported in theft events were Am, Cs, and Ir. The proportion of sources including Am as the sole source or Am combined with Be, or as a companion source with Cs, represented 56% of the total reported as stolen. Key risk factors identified as associated with source theft appear to include portability status, transportation status, transporter status, and radionuclide type. Based on the observations noted, suggested improved security measures are postulated including additional permitting controls, enhanced inspections, improved locking and storage procedures, and steps for communication to the public to enhance the prospects for recovery. Suggested enhancements to further improve data collection are proposed so that crime prevention information can be derived in future research.

Characterization and geographic location of sources of radioactivity lost downhole in the course of oil and gas exploration and production activities in Texas, 1956 to 2001

Case reports describing sources of radioactivity lost downhole in Texas from 1956 to 2001 were obtained from the Texas Department of Health Bureau of Radiation Control and entered into a computerized database. The events of the 45-y period of analysis were characterized, examining aspects such as source type, amount of activity, location of loss, depth, and date of occurrence. Results of the study found that 316 downhole source incidents were reported to the agency during this period of time, representing a total of 426 distinct sources of radioactivity lost downhole within the boundaries of the State of Texas. The sources lost were predominantly AmBe, accounting for 74 TBq of radioactivity at the time of loss, and Cs, accounting for 16.3 TBq of radioactivity. A longitudinal analysis of the data showed the average loss per active oil and gas rig in Texas (known as "rig count") at approximately 24 losses per 1,000 rigs. Specific geographic information was largely missing from many of the records, which prevented the geolocation of wells described to contain lost radioactive sources. As a result, most wells could only be located to the county level, and no comprehensive geographical information system (GIS) map could be accurately created from the data. However, when available, source location information was standardized to permit the characterization of the sources reported as lost. This effort produced the first dedicated compendium of lost downhole sources for the State of Texas and provides an important source of information for regulatory agencies. The ability to provide prompt information about the fate and location of sources of radioactivity is important to regulatory officials, given the recent concerns about radiation source inventory control in the post 9/11 world as it relates to the possible creation of radiological dispersal devices.

An analysis of variables influencing the number of radiation overexposure events in Texas from 1970 to 2000

Sources of radiation are used in a variety of modern work settings, including industrial, medical, research, and agricultural applications. Although regulatory controls exist to limit radiation exposures in these different settings, instances of radiation doses in excess of acceptable limits (referred to as overexposures) do occur. A unique study examined overexposure events in Texas over a 45-y period from 1956 to 2001. The primary purpose of the study was to characterize the factors associated with overexposure events. As part of this characterization, an interesting trend in the number of overexposures by year was observed, but not completely explained. The data revealed a dramatic increase in the number of overexposure events, followed by three apparent phases of decline. These declines are of particular interest because, while the increase and subsequent decrease in overexposures occurred, the number of permits to possess radiation sources in Texas generally increased over the same time period. This study focused on the identification of the factors that led to the trends in overexposure events. Data describing the reported overexposure events in Texas from 1970 to 2000 were obtained from the Texas Department of Health Bureau of Radiation Control (TDH BRC) and entered into a computerized database. With the assistance of senior members of the TDH BRC, the three primary factors influencing the number of overexposures were identified. These included domestic oil and gas exploration and production from 1970 to 2000, wherein sources of radiation are employed in various operations; the establishment of a training and certification requirement for industrial radiographers during the period of 1986 to 1988; and modification of the applicable regulations between 1992 and 1994. The generally accepted indicator of oil and gas exploration and production activity, known as "rig count," is the measure of the number of active oil and gas exploration and production platforms at any given time. Rig count is a parameter of particular interest in Texas because the state's economy is significantly tied to the market value of this important natural resource. The rig count parameter was shown to have a strong correlation with overexposure events (Pearson correlation coefficient of 0.82, p < 0.0001). Interestingly, the sources causing the overexposures indicate that the events stem primarily not from the oil and gas exploration activity itself, but rather from support activities in the form of industrial radiographic procedures. The number of overexposure events was also determined to be influenced by the imposition of the training requirement for radiographers and the modification of the applicable regulations (e.g., the elimination of the quarterly dose limit). The relative magnitude of these influences, however, was far overshadowed by the identified predominant predictor of rig count. The determination of rig count as the significant influencing factor in overexposure events is useful in possibly recognizing the potential for future occurrences of the same nature. This assessment also serves to highlight an apparent significant public health success story, as the number of overexposures per radioactive material licensee is shown to have declined significantly over the 30-y period of study. The factors contributing to this phenomenon are described to serve as a model for use in other settings.

A comparison of the results of regulatory compliance inspections in 1999 by the states of Texas, Maine, and Washington

Inspection outcome data provided by the state of Washington Department of Health, Division of Radiation Protection, for licensees of radioactive materials was encoded according to a system established by the Texas Department of Health, Bureau of Radiation Control. The data, representing calendar year 1999 inspection activities, were then analyzed and the results compared to previously published studies for the same year in the states of Texas and Maine. Despite significant differences in regulatory program size, age, and geographic proximity, the most frequently cited violation for radioactive materials licensees were shown to be similar for all three states. Of particular note were the violations that were identified to be consistently issued in all three states. These included physical inventories and utilization logs not performed, not available, or incomplete; leak testing not performed or not performed on schedule; inadequate or unapproved operating and safety procedures; radiation survey and disposal records not available or incomplete; detection or measurement instrument calibration not performed or records not available; and radiation surveys or sampling not performed or performed with a noncalibrated instrument. Comparisons were made in an attempt to generate a summary of the most commonly issued violations that could be generalized to users of radioactive materials across the United States. A generalized list of common violations would be an invaluable tool for radiation protection programs, serving to aid in the reduction of the overall instance of program non-compliance. Any reduction in instances of non-compliance would result in the conservation of finite public health resources that might then be directed to other pressing public health matters.

An analysis of 45 years of reported overexposure incidents in Texas, 1956 to 2001

Sources of ionizing radiation are commonly encountered in a wide variety of modern work settings. The controls in place to ensure the safe use of these sources have proven to be quite effective, as events involving occupational doses in excess of established limits are quite rare. Nonetheless, instances of doses in excess of established limits, commonly referred to as "overexposures," do occur, but the rarity of such events has resulted in a body of scientific knowledge that consists essentially of sporadic case reports. In this study, incident reports describing radiation overexposure events recorded in Texas from the years 1956 to 2001 were obtained and recorded into a computerized database using a pre-established set of codes. The data were then analyzed for the identification of possible trends or commonalties. During the 45-y period of study, overexposure events accounted for 50% (n = 3,796) of all the radiation-related incidents recorded in Texas for the time period (n = 7,534). Of the overexposure events, 65% (n = 2,342) resulted in the actual deposition of energy in the individual exposed. The remainder were determined to be doses recorded only by a personal dosimetry device. In most of the cases where doses were actually delivered to an individual, the doses were less than 0.05 Sv (5 rem). In only 0.5% of the cases (n = 13) were doses greater than 1 Sv (100 rem). The predominant sources reported as involved in the events included 192Ir, 60Co, and 137Cs. The information derived from the analysis may serve as a basis for a variety of interventions, such as preventative education activities, regulatory modifications, and the possible re-design of equipment identified as commonly associated with such events. The results of the study can also assist in the training of health care providers, as the recognition of common causes and sources of overexposures and subsequent treatments can be forecasted and summary treatment protocols developed.

Sonochemical degradation of phenolic pollutants in aqueous solutions

The sonochemical degradation of phenol, 2-chlorophenol and 3,4-dichlorophenol in aqueous solutions as a function of several operating conditions has been investigated. Experiments were performed at initial substrate concentrations of 0.1, 0.5 and 1 g l(-1), liquid phase volumes of 0.05, 0.07 and 0.08 l, electric power outputs of 125, 187.5 and 250 W, liquid bulk temperatures of 20, 35, 50 and 70 degrees C and an ultrasound frequency of 20 kHz. Substrate concentration was determined as a function of time by means of high performance liquid chromatography. At the conditions under consideration, the rate of degradation follows first order kinetics with respect to the substrate concentration and increases with increasing electric power and decreasing liquid volume. The relative reactivity appears to decrease in the order: 2-chlorophenol > 3,4-dichlorophenol > phenol. Measurements of liquid phase total organic carbon content showed that degradation by-products are more recalcitrant than the original substrate. The rate of 2-chlorophenol degradation was also found to decrease with decreasing liquid bulk temperature and increasing initial concentration. Addition of t-butanol as a hydroxyl radical scavenger only partially inhibited degradation, thus implying that degradation is likely to proceed via both radical-induced and thermal reactions. Addition of Fe2+ ions at concentrations as low as about 0.2 x 10(3) g l(-1) resulted in increased degradation rates; this is attributed to iron being capable of readily decomposing hydrogen peroxide (generated by water sonolysis) in a Fenton-like process to form hydroxyl radicals as well as being an effective oxidation catalyst. The implications of the use of ultrasound in wastewater treatment are also discussed.

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.

Effectively displaying broad scope sub-licensee radioactive material inventory allocations and possession quantities

As part of its annual broad scope license radiation protection program review, the University of Texas Health Science Center at Houston radiation safety program discovered that although inventory control and monitoring mechanisms were being effectively implemented at the sublicensee level, a method did not exist to demonstrate compliance with collective broad scope license possession limits at the institutional level. To address this shortcoming, the radiation safety program data warehouse system was modified, and an automatic summary report showing collective sub-licensee maximum possession authorizations was created. But this report did not effectively present the summary information in a manner that key stakeholders could readily comprehend, as the data was not referenced to collective institutional possession limits. So a graphic version of the summary report was created wherein, for each isotope possessed, the collective institutional limit was displayed, along with the totals of all the individual sub-licensee maximum possession limits and current amounts on hand. This simple graphic served to effectively communicate the current status of the institution's radiation source inventory to the radiation safety committee, executive management, and state regulatory officials. The effort has served to simplify the sometimes-complicated source inventory control process and has facilitated subsequent program reviews. In the future, the method is expected to assist the radiation protection program in anticipating when broad license amendments may be needed to accommodate operational changes.

Statistical validation of a commonly used method for personnel dosimetry issuance determinations

In 1992, the federal requirements for personnel monitoring of occupational radiation doses were modified, making monitoring compulsory only for individuals "likely" to exceed 10% of the applicable annual dose limits. This regulatory change served as a catalyst for many radiation protection programs to re-evaluate their personnel monitoring issuance criteria to determine if some monitoring services might be reduced or eliminated. But in the absence of any clear definition of the term "likely," radiation protection programs relied on adjustments largely based on reviews of previous monitoring results and professional judgment. Although such semi-quantitative assessments may have been appropriate, the approach was not without inherent programmatic risks, as radiation dosimetry programs have been shown to be a consistent source of regulatory non-compliance upon inspection and serve as essential elements in defense against litigation efforts purporting workplace-related radiation injury. The objective of this study was to subject this commonly used method for post-regulatory change dosimetry issuance determinations to statistical validation. Personnel monitoring data from The University of Texas Health Science Center at Houston Radiation Safety Program pre- and post-1992 regulatory changes were accessed and descriptively analyzed. The dynamic nature of the institutional environment made direct comparisons of individuals between years impractical, so 1990 mean dose levels for various independent variables were compared using the Kruskal-Wallis non-parametric ANOVA test at a significance level of alpha = 0.05. The data from 1998 were then analyzed to ascertain if the groupings identified as statistically different in 1990 were still being monitored. The analyses statistically validated the monitoring program reductions made by the University of Texas Health Science Center at Houston radiation protection program. In addition, statistical support for further monitoring program reductions were identified, if such reductions were deemed to be necessary in the future.