CBETA: First Multipass Superconducting Linear Accelerator with Energy Recovery.

Energy recovery has been achieved in a multipass linear accelerator, demonstrating a technology for more compact particle accelerators operating at higher currents and reduced energy consumption. Energy delivered to the beam during the first four passes through the accelerating structure was recovered during four subsequent decelerating passes. High-energy efficiency was achieved by the use of superconducting accelerating cavities and permanent magnets. The fixed-field alternating-gradient optical system used for the return loop successfully transported electron bunches of 42, 78, 114, and 150 MeV in a common vacuum chamber. This new kind of accelerator, an eight-pass energy recovery linac, has the potential to accelerate much higher current than existing linear accelerators while maintaining small beam dimensions and consuming much less energy per electron.

Dynamic expression of JC virus in urine and its relationship to serostatus.

BACKGROUND: There is limited information regarding the daily shedding of JC virus (JCV) in urine and its correlation with serum JCV antibody levels. METHODS: The dynamic expression of JCV in urine and its correlation with JCV antibody status in patients receiving disease modifying therapy for multiple sclerosis were examined in a longitudinal case-control study. JCV antibody index levels were determined using a two-step ELISA (Stratify). JCV shedding in urine samples was determined by quantitative PCR during two 30-day study periods separated by intervals of at least 6 months. RESULTS: Of 42 study subjects (57% female; ages 22-56, average age 39.6 years), 27 (64.3%) were JCV antibody positive (index >0.40) at initial urine collection. Twelve seropositive subjects (44.4%) had detectable JCV in their urine with values ranging from 290 to 5.08 × 108 copies/mL. Daily viral shedding in these patients remained fairly constant throughout the study. Urinary JCV shedding was not detected in any JCV antibody index negative or indeterminate subject. In JCV urinary shedders, the average JCV antibody index was 2.69 (range 1.67-3.57). The average anti-JCV antibody index for the remaining JCV seropositive individuals without viral urinary shedding was 1.35 (range 0.46-3.91). CONCLUSION: MS patients displayed a consistent pattern of JCV shedding over days and months in which higher levels of viruria appeared to have driven higher levels of JCV antibody index. The findings provide additional insights into the dynamic expression of JCV and host response; however, studies in larger populations and of longer duration will be needed to determine their significance to the development of progressive multifocal leukoencephalopathy (PML).

Food Insecurity and Health-Related Quality of Life: A Cross-Sectional Analysis of Older Adults in Florida, U.S.

Individuals 65 years or older will comprise an estimated 20.0% of the U.S. population by 2030. This study investigated the association between food insecurity and health-related quality of life (HRQoL) among an older adult population (n = 234). HRQoL was measured using Healthy Days, a validated survey tool developed by the Centers of Disease Control and Prevention. Food-insecure individuals were more likely to report ≥14 physically unhealthy days (OR = 1.49, 95% CI 0.47-4.78) and ≥14 days with activity limitations (OR = 4.07, 95% CI 0.68-24.1). Although nonsignificant, the findings highlight food insecurity as a potentially important social determinant of health throughout the life course, including at an older age.

WE-E-217BCD-01: Digital Breast Tomosynthesis: Basic Principles and the QMP's Role.

Digital breast tomosynthesis is a form of limited angle tomography, in which section (slice) images are produced from a series of discrete projection images acquired at different angles. Tomosynthesis can be useful in breast imaging by providing potentially better visibility of lesions over conventional mammography, especially in patients with dense breasts. This talk will cover the various physics aspects of DBT, including reconstruction algorithms, the importance of deblurring, and optimizing image acquisition parameters. Remaining important research questions in DBT will be presented and discussed. The presentation will also discuss MQSA Certificate extension process for currently approved digital breast tomosynthesis (DBT) systems. Training requirements, manufacturer required tests for Mammography Equipment Evaluation (MEE) as acceptance tests, and phantom imaging for the purpose of approval of certificate extension will be described. The talk will emphasize the specific tests where special attention must be given and will discuss how the techs should be advised to perform these tests. LEARNING OBJECTIVES: 1. To understand the fundamentals of tomosynthesis reconstruction, including deblurring, algorithm choice, and optimization 2. To understand FDA's certificate extension process for DBT 3. To understand the requirements for MEE 4. To understand the required AEC tracking data Research sponsored in part by NIH, Siemens, and GE Healthcare.

Digital tomosynthesis of hand joints for arthritis assessment.

The two principal forms of hand arthritis, rheumatoid arthritis (RA) and osteoarthritis (OA) have large clinical and economic costs. Radiography has been shown to be a useful tool to assess the condition of the disease. A hand radiograph, however, is a two-dimensional projection of a three-dimensional object. In this report we present the results of a study that applied digital tomosynthesis to hand radiography in order to extract three-dimensional outcome measures that should be more sensitive to arthritis progression. The study was performed using simulated projection radiographs created using micro computed tomography (microCT) and a set of five dry-bone hand skeletons. These simulated projection images were then reconstructed into tomographic slices using the matrix inversion tomosynthesis (MITS) algorithm. The accuracy of the tomosynthesis reconstruction was evaluated by comparing the reconstructed images to a gold standard created using the microCT data. A parameter from image registration science, normalized mutual information, provided a quantifiable figure of merit. This study examined the effects of source displacement, number of reconstructed planes, number of acquisitions, noise added to the gray scale images, and errors in the location of a fiducial marker. We also optimized the reconstruction as a function of two variables k and alpha, that controlled the mixing of MITS with conventional shift-and-add tomosynthesis. A study using hand delineated joint margins demonstrated that MITS images provided a better measurement of average joint space width. We found good agreement between the MITS slices and the true planes. Both joint margins and trabecular structure were visible and the reconstructed slices showed additional structures not visible with the standard projection image. Using hand-delineated joint margins we compared the average joint space width of the gold standard slices to the MITS and projection images. A root-mean square deviation (RMSD), calculated for this comparison, gave RMSDproj = 0.18 mm and RMSDMITS = 0.14 mm for the projection and MITS images, respectively. We have demonstrated the potential of digital tomosynthesis for imaging of the hand to assess arthritic changes. We have also developed a methodology that can be used to optimize the technique and have studied the issues that will control the feasibility of clinical implementation.

The VALUE national hysterectomy study: description of the patients and their surgery.

OBJECTIVES: To describe hysterectomies practised in 1994 and 1995: the patients, their surgery and short term outcomes. DESIGN: One of two large cohorts, with prospective follow up, recruited to compare the outcomes of endometrial destruction with those of hysterectomy. SETTING: England, Wales and Northern Ireland. POPULATION: All women who had hysterectomies for non-malignant indications carried out during a 12-month period. METHODS: Gynaecologists in NHS and independent hospitals were asked to report cases. Follow up data were obtained at outpatient follow up approximately six weeks post-surgery. MAIN OUTCOME MEASURES: Indication for surgery, method of hysterectomy, ovarian status post-surgery, surgical complications. RESULTS: 37,298 cases were reported which is estimated to reflect about 45% of hysterectomies performed during the period studied. The median age was 45 years, and the most common indication for surgery was dysfunctional uterine bleeding (46%). Most hysterectomies were carried out by consultants (55%). The proportions of women having abdominal, vaginal or laparoscopically-assisted hysterectomy were 67%, 30% and 3%, respectively. Forty-three percent of women had no ovaries conserved after surgery. The median length of stay was five days. The overall operative complication rate was 3.5%, and highest for the laparoscopic techniques. The overall post-operative complication rate was 9%. One percent of these was regarded as severe, with the highest rate for severe in the laparoscopic group (2%). There were no operative deaths; 14 deaths were reported within the six-week post-operative period: a crude mortality rate soon after surgery of 0.38 per thousand (95% CI 0.25-0.64). CONCLUSIONS: This large study describes women who undergo hysterectomy in the UK, and presents results on early complications associated with the surgery. Operative complications occurred in one in 30 women, and post-operative complications in at least one in 10. Laparoscopic techniques tend to be associated with higher complication rates than other methods.

Imaging characteristics of an amorphous silicon flat-panel detector for digital chest radiography.

PURPOSE: To evaluate the imaging characteristics of an amorphous silicon flat-panel detector (FPD) for digital chest radiography. MATERIALS AND METHODS: The 41 x 41-cm digital FPD is constructed on a single monolithic glass substrate with a structured cesium iodide scintillator layer and an amorphous silicon thin-film transistor array for image readout. Basic imaging characteristics of the FPD and associated image processing system were assessed on acquired images, including linearity, repeatability, uniformity of response, modulation transfer function (MTF), noise power spectrum, detective quantum efficiency (DQE), contrast sensitivity, and scatter content. Results with the FPD system were compared to those with a storage phosphor computed radiography (CR) system. RESULTS: Images obtained with the FPD demonstrated excellent uniformity, repeatability, and linearity, as well as MTF and DQE that were superior to those with the storage phosphor CR system. The contrast and scatter content of images acquired with the FPD were equivalent to those acquired with the storage phosphor system. CONCLUSION: The FPD provides radiographic images with excellent inherent physical image quality.

Service learning: integrating student learning and community service.

Health professions education is directly effected by changes in health care service delivery and financing systems. In the United States, as the health care industry increasingly shifts to a market economy, service delivery venues are moving away from acute care facilities and into community-based settings. Additionally, there is increased emphasis on primary prevention programs, often provided in public health settings. For health professions programs that traditionally provide clinical training in hospitals and long-term care facilities, there are unique challenges associated with identifying new venues in order to insure that students are exposed to a wide variety of patients with a range of chronic to acute disease conditions. One set of tools that has demonstrated usefulness during these kinds of transitions is service learning. This teaching methodology emphasizes increased partnership with clinical training sites, extensive orientation to patient populations and community resources, structured reflection and instilling the ethic of service in future health care providers. Although this article describes utilization of service learning in the context of current conditions in the United States, we hope that the principles presented here can be readily adapted in any setting.

Racism as a clinical syndrome.

This paper examines the clinical effects of racism on its targets and, in particular, on its agents, the individuals who, wittingly or not, partake of the culture of racial privilege. It proposes a paradigm shift in regard to the clinical study of racism, and presents a structural model of racism, analogous to addiction as a disease, which holds that racism has an etiology and a clinical taxonomy that lends itself to differential diagnosis and treatment of those who manifest symptoms.

Creutzfeldt-Jakob disease in a recipient of a dura mater graft processed in the US: cause or coincidence?

Iatrogenic Creutzfeldt-Jakob disease (CJD) has never been reported among recipients of dura mater grafts processed in the US. We recently investigated a report of such a case in a 72-year-old man with a typical clinical presentation of CJD. We found no evidence of CJD in either the 34-year-old donor or in other, proximal patients undergoing craniotomies. Although the graft may have caused the illness, sporadic CJD is a more likely explanation, with the graft being coincidental.

Seroprevalence and incidence of genital ulcer infections in a rural Ugandan population.

OBJECTIVES: To determine age-sex specific seroprevalence and incidence rates of Treponema pallidum, Haemophilus ducreyi, and HSV-2; to assess the association between HIV-1 status and incidence of these STIs; and HSV-2 serostatus with number of lifetime sexual partners. METHODS: Antibodies against HIV-1, T pallidum, H ducreyi, and HSV-2 infections were tested using approximately 1000 paired (2 year interval) sera collected from a rural adult (15-54 years) population cohort in south west Uganda. RESULTS: Overall HIV-1 prevalence was 4.9%. Prevalence for T pallidum was 12.9% among males and 12.6% among females. The corresponding rates for H ducreyi were 9.8% and 7.3% respectively. HSV-2 prevalence rates were considerably lower in males (36.0%) than in females (71.5%), p < 0.001. Incidence rates for T pallidum per 1000 person years of observation were 8.4 for males and 12.3 for females. The corresponding rates for H ducreyi were 24.6 and 20.0 and for HSV-2 were 73.2 and 122.9 per 1000 person years of observation, respectively. The RR of HSV-2 incidence was 3.69 in HIV seropositive cases versus HIV seronegative after adjusting for age and sex. The corresponding RR for H ducreyi was 3.50 among female HIV positive cases versus negatives with no effect seen in males. Association between HIV-1 prevalence and prevalence of other STIs was significant (Mantel-Haenszel test) for H ducreyi (p = 0.01) and for HSV-2 (p = 0.004) but not for T pallidum (p > 0.4). HSV-2 prevalence was associated with number of lifetime sexual partners (females, p = 0.003; males, p = 0.08). CONCLUSIONS: The results have provided a reliable estimate of the magnitude of the STI problem and demonstrated an association between HIV-1 status and serology of other STIs in a general rural population in sub-Saharan Africa. The study has also highlighted a correlation between HSV-2 seropositivity and number of reported lifetime sexual partners.

Aortic root replacement with the freestyle stentless porcine aortic root bioprosthesis.

BACKGROUND: Stentless porcine prosthetic valves offer several advantages over traditional valves. Among these are superior hemodynamics, laminar flow patterns, lack of need for anticoagulation and perhaps improved durability. METHODS: One hundred and twelve patients were operated on from September 17, 1992 to April 13, 1998 as part of a multi-center worldwide investigation. All patients received a total aortic root replacement. Patients were evaluated postoperatively at discharge, 3 to 6 months, and yearly by clinical exam and color flow Doppler echocardiography. RESULTS: There were 4 deaths either in the hospital or within 30 days after surgery for an operative mortality of 3.6%. No patients experienced structural valve deterioration, non-structural valve deterioration, paravalvular leak, unacceptable hemodynamic performance, or postoperative endocarditis. The linearized rates for survival and thromboembolic complications at 5 years were 82.8% and 90.5% respectively. Excellent hemodynamic function is demonstrated by very low gradients, large EOA, and an exceedingly low incidence of any aortic regurgitation. CONCLUSIONS: The Medtronic Freestyle aortic root bioprosthesis can be used safely to replace the aortic root for aortic valve and aortic root pathology. Root replacement allows optimal hemodynamic performance with no significant aortic regurgitation. Early and intermediate results are encouraging, but further follow-up is needed to determine valve durability.

Gas in the sternoclavicular joints of patients with blunt chest trauma: significance and frequency of CT findings.

OBJECTIVE: In trauma patients, gas (vacuum phenomenon) in the sternoclavicular joints could represent sequelae of significant distraction forces and thus serve as a potential marker for severe intrathoracic injury. We evaluated the significance and frequency of the finding of gas in the sternoclavicular joints on chest CT of patients with blunt trauma. SUBJECTS AND METHODS: We prospectively studied all chest CT examinations performed at our institution over a 14-week period for the finding of gas in the sternoclavicular joints. Chest CT examinations (n = 267) were performed in 234 patients. We excluded data from follow-up CT examinations (n = 33), limiting our evaluation to the initial CT examination for each patient. Of the study population, 103 patients (83 men and 20 women) who ranged in age from 14 to 79 years (mean, 40 years) had sustained blunt chest trauma. For all trauma patients, we recorded the mechanism of injury and the associated thoracic injuries. RESULTS: CT revealed gas in the sternoclavicular joints in 47 patients (21%). Gas was unilateral in 27 patients and bilateral in 20 patients. Sternoclavicular joint gas was seen in 39 (38%) of the 103 trauma patients but was found in only eight (6%) of the 131 nontrauma patients (p < .0001). In the 39 trauma patients with sternoclavicular joint gas, associated thoracic injuries were seen in 17 patients (44%); either a sternal fracture or a retrosternal hematoma was seen in three patients. Radiographically evident thoracic injury was revealed in 20 (31%) of the 64 trauma patients who had no gas in the sternoclavicular joint; however, 10 of these 20 patients had either a sternal fracture or a mediastinal hematoma. CONCLUSION: Although gas in the sternoclavicular joints is more frequently seen in patients with blunt chest trauma than in patients undergoing chest CT for other indications, this finding does not indicate a greater risk of significant mediastinal or thoracic injury.

Performance characteristics of a Kodak computed radiography system.

The performance characteristics of a photostimulable phosphor based computed radiographic (CR) system were studied. The modulation transfer function (MTF), noise power spectra (NPS), and detective quantum efficiency (DQE) of the Kodak Digital Science computed radiography (CR) system (Eastman Kodak Co.-model 400) were measured and compared to previously published results of a Fuji based CR system (Philips Medical Systems-PCR model 7000). To maximize comparability, the same measurement techniques and analysis methods were used. The DQE at four exposure levels (30, 3, 0.3, 0.03 mR) and two plate types (standard and high resolution) were calculated from the NPS and MTF measurements. The NPS was determined from two-dimensional Fourier analysis of uniformly exposed plates. The presampling MTF was determined from the Fourier transform (FT) of the system's finely sampled line spread function (LSF) as produced by a narrow slit. A comparison of the slit type ("beveled edge" versus "straight edge") and its effect on the resulting MTF measurements was also performed. The results show that both systems are comparable in resolution performance. The noise power studies indicated a higher level of noise for the Kodak images (approximately 20% at the low exposure levels and 40%-70% at higher exposure levels). Within the clinically relevant exposure range (0.3-3 mR), the resulting DQE for the Kodak plates ranged between 20%-50% lower than for the corresponding Fuji plates. Measurements of the presampling MTF with the two slit types have shown that a correction factor can be applied to compensate for transmission through the relief edges.

Herpes in the time of AIDS: a comparison of the epidemiology of HIV-1 and HSV-2 in young men in northern Thailand.

OBJECTIVES: To compare the epidemiologic pattern of HIV-1, a recently introduced sexually transmitted disease (STD) agent in Thailand, with the pattern of HSV-2, a well-established STD agent, so that future trends for both viruses can be better understood. METHODS: We obtained questionnaire data and determined HSV-2 (by specific gG-2) and HIV-1 seroreactivity in a cohort of 1,115 young male army conscripts who entered service in northern Thailand in 1991. RESULTS: Seroprevalence of HIV-1 and HSV-2 was 6.9% and 14.9%, respectively. For HSV-2-seropositive men who reported previous genital ulcers, HIV-1 seroprevalence was 32%. For most variables, there was a close correspondence between the prevalence ratios for HIV-1 and for HSV-2, except that prevalence ratios for HIV-1 tended to be greater than the corresponding ratios for HSV-2. The seroprevalence of both viruses was strongly related to early and frequent contact with female sex workers (FSWs), infrequent use of condoms with FSWs, and residence in the upper north region of Thailand. When differences in sexual behavior between the upper north and lower north were controlled for, the seroprevalence of both viruses still differed significantly by region. CONCLUSIONS: Although the seroprevalence levels of HSV-2 and HIV-1 were quite different in this cohort of Thai army conscripts in 1991, the patterns of infection in terms of demographic, residential, and behavioral variables were similar. Seroprevalence studies of HSV-2 in other populations, particularly where the HIV-1 epidemic is just beginning, may be useful in predicting which subgroups might be most vulnerable to the epidemic and could therefore benefit the most from public health intervention. Where differences in the patterns of the two viruses have been noted, we hypothesize that the pattern for HIV-1 will evolve toward that seen for HSV-2.

PIP: Herpes simplex virus type 2 (HSV-2) has been in Thailand longer than has been HIV-1. The epidemiology of the 2 viruses was compared in an attempt to gain insight into likely future trends of the dissemination of HIV-1 and HSV-2 in the country. Findings are based upon questionnaire and serostatus data on a cohort of 1115 young male army conscripts who entered service in northern Thailand in 1991. The 1061 conscripts were 21 years old and the remainder were 22-27 years old. 879 were unmarried, 598 were farmers, and 55 were students. 6.9% of the young men were infected with HIV-1 and 14.9% with HSV-2. Among HSV-2-seropositive men who reported previous genital ulcers, HIV-1 seroprevalence was 32%. For most variables, there was a close correspondence between the prevalence ratios for HIV-1 and HSV-2, except that prevalence ratios for HIV-1 tended to be greater than the corresponding ratios for HSV-2. The seroprevalence of both viruses was strongly related to early and frequent contact with female prostitutes, infrequent condom use with such prostitutes, and residence in the upper northern region of Thailand. The patterns of infection were similar for the 2 viruses, suggesting the direction in which HIV-1 seroprevalence levels will go.

The epidemiology of chronic fatigue in San Francisco.

Despite considerable research on chronic fatigue syndrome (CFS) and conditions associated with unexplained chronic fatigue (CF), little is known about their prevalence and demographic distribution in the population. The present study describes the epidemiology and characteristics of self-reported CF and related conditions in a diverse urban community. The study used a cross-sectional telephone screening survey of households in San Francisco, followed by interviews with fatigued and nonfatigued residents. Respondents who appeared to meet case definition criteria for CFS, based on self-reported fatigue characteristics, symptoms, and medical history, were classified as CFS-like cases. Subjects who reported idiopathic chronic fatigue (ICF) that did not meet CFS criteria were classified as ICF-like cases. Screening interviews were completed for 8,004 households, providing fatigue and demographic information for 16,970 residents. Unexplained CF was extremely rare among household residents <18 years of age, but was reported by 2% of adult respondents. A total of 33 adults (0.2% of the study population) were classified as CFS-like cases and 259 (1.8%) as ICF-like cases. Neither condition clustered within households. CFS- and ICF-like illnesses were most prevalent among women and persons with annual household incomes below $40,000, and least prevalent among Asians. The prevalence of CFS-like illness was elevated among African Americans, Native Americans, and persons engaged in clerical occupations. Although CFS-like cases were more severely ill than those with ICF-like illness, a similar symptom pattern was observed in both groups. In conclusion, conditions associated with unexplained CF occur in all sociodemographic groups but appear to be most prevalent among women, persons with lower income, and some racial minorities.

Understanding learning styles. Implications for staff development educators.

The authors present information for understanding diverse learning styles among RNs. Various learning-style assessment tools are presented. Emphasis is placed on the use of a learning-style instrument that addresses multiple learning-style constructs. Implications for staff development educators are discussed.

Helical CT with only colonic contrast material for diagnosing diverticulitis: prospective evaluation of 150 patients.

OBJECTIVE: We prospectively evaluated a helical CT technique in which contrast material is administered only through the colon for the imaging of suspected diverticulitis. SUBJECTS AND METHODS: One hundred fifty consecutive patients who presented to our emergency department with clinically suspected diverticulitis underwent helical abdominal CT after contrast material was administered only through the colon. CT findings of diverticulitis included diverticula, muscular wall hypertrophy, focal colonic wall thickening, and pericolonic fat stranding. CT results were correlated with clinical follow-up (all patients) and with pathologic findings (41 patients). RESULTS: A final clinical diagnosis of diverticulitis was made in 64 patients (43%), of whom 62 (97%) had CT results positive for diverticulitis. Of the 86 patients for whom diverticulitis was clinically excluded, all (100%) had CT results that were negative for diverticulitis. CT interpretations had a sensitivity of 97%, a specificity of 100%, a positive predictive value of 100%, a negative predictive value of 98%, and an overall accuracy of 99%. Alternative diagnoses were noted on CT in 50 (58%) of 86 patients who did not have diverticulitis and included 50 (78%) of the 64 patients in whom an alternative condition other than nonspecific abdominal pain was established. CONCLUSION: Helical CT obtained after contrast material administered only through the colon is accurate (99%) for confirming or excluding clinically suspected diverticulitis and for suggesting alternative conditions (78%) when they are present. This CT technique avoids the risks, discomforts, and costs of oral and i.v. contrast material administration and allows immediate scanning.

Zyme, a novel and potentially amyloidogenic enzyme cDNA isolated from Alzheimer's disease brain.

The deposition of the beta amyloid peptide in neuritic plaques and cerebral blood vessels is a hallmark of Alzheimer's disease (AD) pathology. The major component of the amyloid deposit is a 4.2-kDa polypeptide termed amyloid beta-protein of 39-43 residues, which is derived from processing of a larger amyloid precursor protein (APP). It is hypothesized that a chymotrypsin-like enzyme is involved in the processing of APP. We have discovered a new serine protease from the AD brain by polymerase chain reaction amplification of DNA sequences representing active site homologous regions of chymotrypsin-like enzymes. A cDNA clone was identified as one out of one million that encodes Zyme, a serine protease. Messenger RNA encoding Zyme can be detected in some mammalian species but not in mice, rats, or hamster. Zyme is expressed predominantly in brain, kidney, and salivary gland. Zyme mRNA cannot be detected in fetal brain but is seen in adult brain. The Zyme gene maps to chromosome 19q13.3, a region which shows genetic linkage with late onset familial Alzheimer's disease. When Zyme cDNA is co-expressed with the APP cDNA in 293 (human embryonic kidney) cells, amyloidogenic fragments are detected using C-terminal antibody to APP. These co-transfected cells release an abundance of truncated amyloid beta-protein peptide and shows a reduction of residues 17-42 of Abeta (P3) peptide. Zyme is immunolocalized to perivascular cells in monkey cortex and the AD brain. In addition, Zyme is localized to microglial cells in our AD brain sample. The amyloidogenic potential and localization in brain may indicate a role for this protease in amyloid precursor processing and AD.