Critical preparedness and operational response actions directed for the acute and post-acute COVID-19 pandemic in Brazil: the experience of a nationwide outpatient healthcare group

ABSTRACT

While the new Coronavirus Disease 2019 (COVID-19) pandemic rapidly spread across the world, South America was reached later in relation to Asia, Europe and the United States of America (USA). Brazil concentrates now the largest number of cases in the continent and, as the disease speedily progressed throughout the country, prompt and challenging operational strategies had to be taken by institutions caring for COVID-19 and non-COVID-19 patients in order to assure optimal workflows, triage, and management. Although hospitals in the USA, Europe and Asia have shared their experience on this subject, little has been discussed about such strategies in South America or by the perspective of outpatient centers, which are paramount in the radiology field. This article shares the guidelines adopted early in the pandemic by a nationwide outpatient healthcare center composed by a network of more than 200 patient service centers and nearly 2,000 radiologists in Brazil, discussing operational and patient management strategies, staff protection, changes adopted in the fellowship program, and the effectiveness of such measures.

Occupational radiation exposure and risk of cataract incidence in a cohort of US radiologic technologists

It has long been known that relatively high-dose ionising radiation exposure (> 1 Gy) can induce cataract, but there has been no evidence that this occurs at low doses (< 100 mGy). To assess low-dose risk, participants from the US Radiologic Technologists Study, a large, prospective cohort, were followed from date of mailed questionnaire survey completed during 1994-1998 to the earliest of self-reported diagnosis of cataract/cataract surgery, cancer other than non-melanoma skin, or date of last survey (up to end 2014). Cox proportional hazards models with age as timescale were used, adjusted for a priori selected cataract risk factors (diabetes, body mass index, smoking history, race, sex, birth year, cumulative UVB radiant exposure). 12,336 out of 67,246 eligible technologists reported a history of diagnosis of cataract during 832,479 person years of follow-up, and 5509 from 67,709 eligible technologists reported undergoing cataract surgery with 888,420 person years of follow-up. The mean cumulative estimated 5-year lagged eye-lens absorbed dose from occupational radiation exposures was 55.7 mGy (interquartile range 23.6-69.0 mGy). Five-year lagged occupational radiation exposure was strongly associated with self-reported cataract, with an excess hazard ratio/mGy of 0.69 × 10-3 (95% CI 0.27 × 10-3 to 1.16 × 10-3, p < 0.001). Cataract risk remained statistically significant (p = 0.030) when analysis was restricted to < 100 mGy cumulative occupational radiation exposure to the eye lens. A non-significantly increased excess hazard ratio/mGy of 0.34 × 10-3 (95% CI - 0.19 × 10-3 to 0.97 × 10-3, p = 0.221) was observed for cataract surgery. Our results suggest that there is excess risk for cataract associated with radiation exposure from low-dose and low dose-rate occupational exposures.

Can radiological technologists serve as primary screeners of low-dose computed tomography for the diagnosis of lung cancer?

BACKGROUND

The Accreditation Council for Lung Cancer CT Screening of Japan established guidelines for the certification of Radiological Technologists in 2009.

OBJECTIVE

To analyze the trends in examination pass rates of the Radiological Technologists and discuss the reasons.

METHODS

The cohort comprised 1593 Radiological Technologists (as examinees) based on 10-year of data (with a total of 17 examination runs). First, the examinees' written test results were analyzed. Second, an abnormal finding detection test was conducted using >100 client PCs connected to a dedicated server containing low-dose lung cancer CT screening images of 60 cases. The passing scores were correct answer rate >60% and sensitivity (TP) of >90%, respectively.

RESULTS

Overall, 1243 examinees passed with an overall rate of 78%. The average pass rate for the written test was 91%, whereas that for the abnormal findings detection test was 85%. There was a moderate correlation between the test pass rate and average years of clinical experience of the examinees for the abnormal findings detection test (R = 0.558), whereas no such correlation existed for the written test (R = 0.105).

CONCLUSIONS

In order for accredited Radiological Technologists to serve as primary screeners of low-dose computed tomography, it is important to revise the educational system according to current standard practices.

Supply/Demand in Radiology: A Historical Perspective and Comparison to other Labor Markets

RATIONALE AND OBJECTIVES

There has been attention on the job market recently and on radiology's supply/demand calculus. Supply is influenced by the number of trained radiologists, while demand is driven by demographics and technological innovation. We analyze the supply of radiologists historically and compare to other labor markets-medical and non-medical, domestic and foreign.

MATERIALS AND METHODS

We review National Resident Matching Program data in radiology and several other specialties from 1991 to 2015. We also review surveys, physician recruitment data, and peer-reviewed commentaries on medical specialty job markets. Trends are compared across specialties. The regulation of American medical training is compared to that in the United Kingdom and to a nonmedical labor market, unionized theatrical stage employees.

RESULTS

Radiology residency positions have increased since 1998 despite a downturn in the job market. This expansion coincides with a decreasing percentage of positions filled by domestic graduates. A similar trend has been seen in pathology, a notoriously oversupplied specialty. Conversely, other specialties have maintained their proportion of domestic graduates by way of limited supply or implicit demand.

CONCLUSIONS

The radiology job market is currently oversupplied, primarily a result of increasing residency positions despite indicators of decreasing demand. The percentage of residency positions filled by domestic graduates has decreased during the same period, suggesting that medical student interest is responsive to the market. Other specialties, particularly pathology, demonstrate the dangers of chronic oversupply. We advocate a reduction of radiology residency positions such that supply closely approximates demand without exceeding it. Additional measures may be taken, if necessary, to restore market equilibrium in the event of a mild undersupply.

A national survey of occupational radiation exposure among diagnostic radiologic technologists in South Korea

The objective of this study was to investigate representative occupational characteristics and radiation exposure for South Korean radiologic technologists. The authors conducted a national survey by stratified sampling of South Korean administrative districts and types of medical facilities. A total of 585 technologists were surveyed, and survey data were linked with dosimetry data from the National Dose Registry. A total of 73 % of radiologic technologists sampled were male, 62 % were younger than age 40 and 86.5 % began employment after 1990. The most frequent practices among radiologic technologists were diagnostic routine X-ray followed by computed tomography (CT) and portable X-ray. Male workers were more frequently involved in CT, portable X-ray and interventional radiology whereas female workers carried out most mammography procedures. The average annual effective dose was 2.3 mSv for male and 1.3 mSv for female workers. The dose was significantly higher for workers in the provinces and those who had recently started work.

Occupational ionising radiation and risk of basal cell carcinoma in US radiologic technologists (1983-2005)

OBJECTIVE

To determine risk for incident basal cell carcinoma from cumulative low-dose ionising radiation in the US radiologic technologist cohort.

METHODS

We analysed 65,719 Caucasian technologists who were cancer-free at baseline (1983-1989 or 1994-1998) and answered a follow-up questionnaire (2003-2005). Absorbed radiation dose to the skin in mGy for estimated cumulative occupational radiation exposure was reconstructed for each technologist based on badge dose measurements, questionnaire-derived work history and protection practices, and literature information. Radiation-associated risk was assessed using Poisson regression and included adjustment for several demographic, lifestyle, host and sun exposure factors.

RESULTS

Cumulative mean absorbed skin dose (to head/neck/arms) was 55.8 mGy (range 0-1735 mGy). For lifetime cumulative dose, we did not observe an excess radiation-related risk (excess relative risk/Gy=-0.01 (95% CI -0.43 to 0.52). However, we observed that basal cell carcinoma risk was increased for radiation dose received before age 30 (excess relative risk/Gy=0.59, 95% CI -0.11 to 1.42) and before 1960 (excess relative risk/Gy=2.92, 95% CI 1.39 to 4.45).

CONCLUSIONS

Basal cell carcinoma risk was unrelated to low-dose radiation exposure among radiologic technologists. Because of uncertainties in dosimetry and sensitivity to model specifications, both our null results and our findings of excess risk for dose received before age 30 and exposure before 1960 should be interpreted with caution.

Relationships Between Self-Reported Leadership Practices, Job Satisfaction, and Demographics of Radiology Administrators

PURPOSE

To evaluate the self-reported leadership practices of radiology administrators and the demographic characteristics associated with those leadership practices. The effect of these demographic characteristics and leadership practices on job satisfaction also was studied.

METHODS

One-hundred forty-nine American Society of Radiologic Technologists members who indicated they have a position of administrator/manager, chief technologist, or supervisor completed a demographic survey and the Leadership Practices Inventory (LPI) self-survey tool. The LPI divides successful leadership into 5 practices: Challenge the Process, Inspire a Shared Vision, Enable Others to Act, Encourage the Heart, and Model the Way.

RESULTS

The categories Challenge the Process and Inspire a Shared Vision had the lowest mean scores and the widest variation. Having had formal leadership training and being older were demographic characteristics associated with higher LPI scores. Having a higher LPI score and having had formal leadership training were associated with higher job satisfaction.

DISCUSSION

Formal leadership training was the only statistically significant variable when using LPI score as the response variable.

CONCLUSION

The results of this study show that radiology administrators would benefit from formal leadership training that focuses on challenging the process and inspiring a shared vision.

Degree requirement & employment opportunity in radiologic science

OBJECTIVE

To estimate the short-term effect of increasing the minimum education requirement for primary certification examination eligibility on employment opportunities in the radiologic sciences in the United States.

METHODS

Data was gathered from the websites of academic institutions, accrediting agencies, and certification bodies to determine the percentages of education programs that offer radiologic technology students certificates, associate degrees, bachelor's degrees, or master's degrees.

RESULTS

Approximately one-third of radiologic science education programs currently award certificates to their graduates.

DISCUSSION

Some certificate programs appear to be reacting slowly to the increasing of the minimum education requirement. In addition, there appears to be some recent cutbacks in the total number of professional education programs. Perhaps unfortunately, the time frame in which many education programs have been attempting to transition to award students an associate degree upon program completion has coincided with the recent period of global economic turmoil.

CONCLUSION

The short-term effect of increasing the minimum education requirement on radiologic science employment opportunities could be large and non-negligible. Thus, employment opportunities for imaging professionals could grow faster than currently projected, as the supply of graduates meeting the increased minimum education requirement of an associate degree could be limited in the short term.

Level of accessibility of radiological diagnostic tools of high technology and its effect on human health: study of ultrasonography, CT scan and MRI in different perspective

The study was conducted at JNMC, Aligarh, India, to discern the obstacles/hurdles that stood in the way of the patients and the high technology diagnostic tool. For this purpose several parameters were taken eg, education/literacy, occupation and income group, etc. From the study 97% chose to undergo USG and only 3% were defaulters; 86% chose to undergo CT scan and only 14% were defaulters; 79% chose to undergo MRI and 21% were defaulters. Low cost investigations ie, USG and CT scan were more prescribed to IVth social class but MRI was mostly prescribed to IInd. Most of the defaulters were from IVth social class and showed financial problem for getting investigation. Taking into consideration the cost and sensitivity of procedure, it was found in this study that mainly cost determines the outcome. Sensitivity did not matter in patient's perspective. This was the reason that maximum defaulters were found in MRI, followed by CT scan and least in USG. Financial constraint was primary reason declared by defaulters followed by distance. Additional parameters like literacy, occupation and social standing were also found significant in the study in the sense of prescription of investigation and being defaulter.

U.S. Technologists' radiation exposure perceptions and practices

BACKGROUND

Despite early recognition of the potential hazards of ionizing radiation and research documenting these hazards over the past 115 years, problems persist regarding the safety of medical procedures that use ionizing radiation for imaging.

OBJECTIVE

This investigation sought to evaluate current attitudes and radiation protection practices among radiologic technologists following recent reports of the dramatic increase in radiation dose in the United States.

METHOD

A survey was sent to a stratified random sample of 2000 radiologic technologists in the U.S. whose names were obtained from the American Registry of Radiologic Technologists.

RESULTS

Radiographers are aware of the increase in exposure to the U.S. population from medical sources and some of their self-reported observations and practices are contributing to this increase.

CONCLUSION

Radiologic technologists are aware of exposure increases and may be contributing to the increase in patient dose in the U.S., largely because there is a lack of in-service education. Commonly recognized and accepted methods of radiation protection practices are being applied to reduce dose to U.S. patients, but not routinely so. These skills require periodic updates and reminders.

Analyzing the glass ceiling effect among radiologic technologists

BACKGROUND

The literature has suggested that advancement within politics, academia and the health professions is influenced by gender. Purpose The authors conducted a survey to determine whether advancement was equal by gender in the radiologic science disciplines of nuclear medicine technology, radiation therapy and radiography.

METHODS

The survey was mailed to 900 subjects, 300 from each discipline. The discipline groups were further stratified by initial year of American Registry of Radiologic Technology certification; the authors selected 100 subjects from each discipline who initially were certified in 1978, 100 in 1988 and 100 in 1998.

RESULTS

Approximately 33% of those selected responded. The findings of the study provided no evidence that men are promoted differentially than women. Women perceived that men were paid more for the same work. It appears that gender bias is pervasive outside of promotion decisions and, indeed, that some illegal actions (eg, sexual harassment, inappropriate gender-related interview questions) take place in radiologic science clinical settings.

CONCLUSION

It is hoped that this study will set a baseline for future research on whether there is a glass ceiling effect in radiologic clinical practice and stimulate discussion of the importance of equal opportunity regardless of gender.

An evaluation of cone-beam computed tomography use in postgraduate orthodontic programs in the United States and Canada

The purpose of this study was to evaluate the use of cone-beam computed tomography (CBCT) in postgraduate orthodontic residency programs. An anonymous electronic survey was sent to the program director/chair of each of the sixty-nine United States and Canadian postgraduate orthodontic programs, with thirty-six (52.2 percent) of these programs responding. Overall, 83.3 percent of programs reported having access to a CBCT scanner, while 73.3 percent reported regular usage. The vast majority (81.8 percent) used CBCT mainly for specific diagnostic purposes, while 18.2 percent (n=4) used CBCT as a diagnostic tool for every patient. Orthodontic residents received both didactic and practical (hands-on) training or solely didactic training in 59.1 percent and 31.8 percent of programs, respectively. Operation of the CBCT scanner was the responsibility of radiology technicians (54.4 percent), both radiology technicians and orthodontic residents (31.8 percent), and orthodontic residents alone (13.6 percent). Interpretation of CBCT results was the responsibility of a radiologist in 59.1 percent of programs, while residents were responsible for reading and referring abnormal findings in 31.8 percent of programs. Overall, postgraduate orthodontic program CBCT accessibility, usage, training, and interpretation were consistent in Eastern and Western regions, and most CBCT use was for specific diagnostic purposes of impacted/supernumerary teeth, craniofacial anomalies, and temporomandibular joint (TMJ) disorders.

Long radiology workdays reduce detection and accommodation accuracy

PURPOSE

The aim of this study was to measure the diagnostic accuracy of fracture detection, visual accommodation, reading time, and subjective ratings of fatigue and visual strain before and after a day of clinical reading.

METHODS

Forty attending radiologists and radiology residents viewed 60 deidentified, HIPAA-compliant bone examinations, half with fractures, once before any clinical reading (early) and once after a day of clinical reading (late). Reading time was recorded. Visual accommodation (the ability to maintain focus) was measured before and after each reading session. Subjective ratings of symptoms of fatigue and oculomotor strain were collected. The study was approved by local institutional review boards.

RESULTS

Diagnostic accuracy was reduced significantly after a day of clinical reading, with average areas under the receiver operating characteristic curves of 0.885 for early reading and 0.852 for late reading (P < .05). After a day of image interpretation, visual accommodation was no more variable, though error in visual accommodation was greater (P < .01), and subjective ratings of fatigue were higher.

CONCLUSIONS

After a day of clinical reading, radiologists have reduced ability to focus, increased symptoms of fatigue and oculomotor strain, and reduced ability to detect fractures. Radiologists need to be aware of the effects of fatigue on diagnostic accuracy and take steps to mitigate these effects.

Radiography students' clinical learning styles

PURPOSE

To examine the common learning styles of radiography students during clinical practice.

METHODS

Descriptive research methodology, using a single self-report questionnaire, helped to identify common learning styles of radiography students during clinical practice.

RESULTS

The results indicated that 3 learning styles predominate among radiography students during clinical practice: task oriented, purposeful and tentative.

CONCLUSION

Insight into clinical practice learning styles can help students understand how they learn and allow them to recognize ways to maximize learning. It also heightens awareness among clinical instructors and technologists of the different learning styles and their relevance to clinical practice education.

Radiologic science educator stress and burnout

PURPOSE

To examine the perceived level of occupational stress and burnout of radiologic science educators.

METHODS

The Maslach Burnout Inventory (MBI) with health status and demographic survey was sent by e-mail to 241 members of the Association of Educators in Imaging and Radiologic Sciences Inc. The survey yielded a 62% response rate. Independent sample t-tests, regression analysis and one-way ANOVAs were used to compare data.

RESULTS

Results indicated average levels for radiologic science educator feelings of emotional exhaustion, low levels for their feelings of depersonalization and average levels for their feelings of personal accomplishment. A statistically significant result was found between all 3 subscales of the MBI and the reported health status.

CONCLUSION

This research study may help raise awareness of stress and burnout and their relationship to the health of radiologic science educators.

Retrospective biodosimetry among United States radiologic technologists

Measurement of chromosome translocations in peripheral blood lymphocytes has been used to quantify prior exposure to ionizing radiation, including for workers exposed to low, chronic doses. We assessed translocation frequencies in a subset of U.S. radiologic technologists to substantiate ionizing radiation dose estimates developed for 110,418 technologists who worked between 1916 and 1984. From 3,441 cohort members known to have begun working before 1950, we selected a sample of 152, stratified by estimated cumulative dose, over-sampling from higher-dose categories and excluding persons with a prior cancer diagnosis, a personal or family history of chromosomal instability disorders, or a current history of smoking. Estimates of film-badge dose ranged from less than 10 cSv to more than 30 cSv. Blood samples, obtained in 2004, were analyzed by fluorescence in situ hybridization (FISH) whole chromosome painting by simultaneously labeling chromosomes 1, 2 and 4 in red and 3, 5 and 6 in green. Translocations were scored in 1800 well-spread metaphase cells and expressed per 100 cell equivalents (CE) per person. Linear Poisson regression models with allowance for overdispersion were used to assess the relationship between estimated occupational red bone marrow absorbed dose in cGy and translocation frequency, adjusted for age, gender and estimated red bone marrow absorbed dose score from personal diagnostic procedures. We observed 0.09 excess translocations per 100 CE per cGy red bone marrow dose (95% CI: -0.01, 0.2; P = 0.07), which is similar to the expected estimate based on previous cytogenetic studies (0.05 excess translocations per 100 CE per cGy). Despite uncertainty in the estimates of occupational red bone marrow absorbed doses, we found good general agreement between the doses and translocation frequencies, lending support to the credibility of the dose assessment for this large cohort of U.S. radiologic technologists.

Factors affecting radiographers' organizational commitment

CONTEXT

A variety of factors influence employees' attitudes toward their workplace and commitment to the organization that employs them. However, these factors have not been well documented among radiologic technologists.

OBJECTIVE

To determine the predictive ability of selected organizational, leadership, work-role and demographic variables on organizational commitment for a national sample of radiographers.

METHODS

Three thousand radiographers registered by the American Registry of Radiologic Technologists working full time in clinical settings were surveyed by mail regarding their commitment to their employers, leadership within the organization that employs them, employer support and demographic information.

RESULTS

Overall, radiographers were found to have only a moderate level of commitment to their employers. Among the factors that significantly affected commitment were the radiographer's educational level, perceived level of organizational support, role clarity and organizational leadership.

CONCLUSION

The results of this study could provide managers and supervisors with insights on how to empower and challenge radiographers and offer opportunities that will enhance radiographers' commitment to the organization, thus reducing costly turnover and improving employee performance.

Effect of training and experience on qualitative and quantitative CT perfusion data

BACKGROUND AND PURPOSE

To evaluate interobserver reliability of obtaining CT perfusion (CTP) data for qualitative identification of perfusion abnormality and quantitative assessment through regions-of-interest (ROIs) placement.

MATERIALS AND METHODS

Six observers participated in the study (neuroradiology attending physician, neurology attending physician, neuroradiology fellow, radiology resident physician, senior and junior CT technologists). After a brief training session, each observer evaluated 20 CTP datasets for qualitative identification of a right- or left-sided perfusion abnormality or symmetric perfusion. Observers also placed a single ROI of standard size to obtain quantitative data on the most severely hypoperfused region. An additional 10 ROIs were placed on the cortex to quantitatively evaluate global cortical perfusion. Mean quantitative cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) values were analyzed.

RESULTS

The kappa values for qualitative assessment of a perfusion abnormality ranged from 0.55 to 1.0. Coefficients of variation for quantitative assessment of ischemia/infarct region were 27.10% for CBF, 13.33% for CBV, and 4.66% for MTT. Coefficients of variation for quantitative assessment of global cortical perfusion were 11.88% for CBF, 13.66% for CBV, and 3.55% for MTT. The junior CT technologist and neuroradiology fellow showed significant differences compared with other observers for the ischemia/infarct region and global cortical perfusion, respectively.

CONCLUSION

Overall, quantitative differences seen in this study would not necessarily affect quality of interpretation of ischemia/infarct region or global cortical perfusion. Therefore, obtaining qualitative and quantitative CTP data can reliably be performed in the clinical setting among observers with various levels of skill and experience when using a uniform and standard technique.

Academic tenure in radiologic technology--revisited

CONTEXT

Academic tenure is important to most educators, including those in the radiologic sciences; however, many factors can influence an educator's ability to attain tenure.

OBJECTIVE

This article empirically examines the concept of tenure among radiologic science educators using data from a national survey of registered radiologic technology educators.

RESULTS

Greater proportions of tenured and tenure-eligible faculty held higher academic rank, had higher levels of education and were employed by 2- and 4-year colleges or universities compared with nontenure-track faculty. Also, tenured R.T. educators tended to be older than tenure-eligible and nontenure-track faculty.

SUMMARY

R.T. educators are a diverse group, and attention should focus on the individual needs of educators in a variety of professional settings.

Interventional radiography and mortality risks in U.S. radiologic technologists

With the exponential increase in minimally invasive fluoroscopically guided interventional radiologic procedures, concern has increased about the health effects on staff and patients of radiation exposure from these procedures. There has been no systematic epidemiologic investigation to quantify serious disease risks or mortality. To quantify all-cause, circulatory system disease and cancer mortality risks in U.S. radiologic technologists who work with interventional radiographic procedures, we evaluated mortality risks in a nationwide cohort of 88,766 U.S. radiologic technologists (77% female) who completed a self-administered questionnaire during 1994-1998 and were followed through 31 December 2003. We obtained information on work experience, types of procedures (including fluoroscopically guided interventional procedures), and protective measures plus medical, family cancer history, lifestyle, and reproductive information. Cox proportional hazards regression models were used to compute relative risks (RRs) with 95% confidence intervals (CIs). Between completion of the questionnaire and the end of follow-up, there were 3,581 deaths, including 1,209 from malignancies and 979 from circulatory system diseases. Compared to radiologic technologists who never or rarely performed or assisted with fluoroscopically guided interventional procedures, all-cause mortality risks were not increased among those working on such procedures daily. Similarly, there was no increased risk of mortality resulting from all circulatory system diseases combined, all cancers combined, or female breast cancer among technologists who daily performed or assisted with fluoroscopically guided interventional procedures. Based on small numbers of deaths (n=151), there were non-significant excesses (40%-70%) in mortality from cerebrovascular disease among technologists ever working with these procedures. The absence of significantly elevated mortality risks in radiologic technologists reporting the highest frequency of interventional radiography procedures must be interpreted cautiously in light of the small number of deaths during the relatively short follow-up. The present study cannot rule out increased risks of cerebrovascular disease, specific cancers, and diseases with low case-fatality rates or a long latency period preceding death.

Estimating Historical Radiation Doses to a Cohort of U.S. Radiologic Technologists

Data have been collected and physical and statistical models have been constructed to estimate unknown occupational radiation doses among 90,000 members of the U.S. Radiologic Technologists cohort who responded to a baseline questionnaire during the mid-1980s. Since the availability of radiation dose data differed by calendar period, different models were developed and applied for years worked before 1960, 1960- 1976 and 1977-1984. The dose estimation used available film-badge measurements (approximately 350,000) for individual cohort members, information provided by the technologists on their work history and protection practices, and measurement and other data derived from the literature. The dosimetry model estimates annual and cumulative occupational badge doses (personal dose equivalent) for each technologist for each year worked from 1916 through 1984 as well as absorbed doses to organs and tissues including bone marrow, female breast, thyroid, ovary, testes, lung and skin. Assumptions have been made about critical variables including average energy of X rays, use of protective aprons, position of film badges, and minimum detectable doses. Uncertainty of badge and organ doses was characterized for each year of each technologist's working career. Monte Carlo methods were used to generate estimates of cumulative organ doses for preliminary cancer risk analyses. The models and predictions presented here, while continuing to be modified and improved, represent one of the most comprehensive dose reconstructions undertaken to date for a large cohort of medical radiation workers.

Measurement error of lumbar total disc replacement range of motion

STUDY DESIGN

A retrospective review of lumbar total disc replacement (TDR) radiographs.

OBJECTIVE

To determine the error and variability in measuring TDR radiographic range of motion (ROM).

SUMMARY OF BACKGROUND DATA

Motion preservation is the driving force behind lumbar TDR technology. In the recent literature, sagittal radiographic TDR ROM as low as 2 degrees has been reported. In these studies, ROM was determined by using the Cobb method to measure TDR sagittal alignment angles in flexion-extension lateral radiographs. However, previous studies in the spinal deformity literature have shown that the Cobb method is very susceptible to measurement error.

METHODS

There were 5 observers, including 2 attending orthopedic spine surgeons, 1 spine fellow, 1 fifth-year resident, and 1 fourth-year resident, who measured the ROM of 50 ProDisc II (Synthes Spine Solutions, New York, NY) TDRs on standard flexion-extension lumbar spine radiograph sets. Repeated measurements were made on 2 occasions using the Cobb method. Measurement variability was calculated using 3 statistical methods.

RESULTS

The 3 statistical methods resulted in extremely similar values for TDR ROM observer variability. Overall, the intraobserver variability of TDR ROM measurement was +/-4.6 degrees, and interobserver variability was +/-5.2 degrees .

CONCLUSIONS

To be 95% certain that an implanted TDR prosthesis has any sagittal motion, a ROM of at least 4.6 degrees must be observed, which is the upper limit of intraobserver measurement variability for a TDR with a true ROM of 0 degrees. To be 95% certain that a change in TDR ROM has occurred between 2 measurements by the same observer, a change in ROM of at least 9.6 degrees must be observed (the entire range of +/-4.6 degrees intraobserver variability). ROM measurement variability should be considered when evaluating the success or failure of motion preservation in lumbar TDR.

Patterns of care for brachytherapy in Europe results in Spain

INTRODUCTION

In 2003 ESTRO began a project whose primary objective, was to make a map in the European area of infrastructures in technology and personnel for brachytherapy.

MATERIAL AND METHOD

A survey and a web site were elaborated. The survey was sent to the 76 Spanish Radiation Oncology departments in May 2003.

RESULTS

By the end of 2003, 66 (86.8%) services had responded, 40 (71.4%) of which had brachytherapy. The services with brachytherapy treated 73.5% of the total patients, an average of 1,199 patients. The mean number of patients treated with brachytherapy by department was 135.5 and the number of applications was 265 annually. The average number of specialists was 7, 4 of them trained in brachytherapy. The average weekly work load of the radiation oncologists, physicists, and technicians was 22.6 h, 13.8 h and 21.0 h, respectively. The mean time dedicated to each patient by radiation oncologists, physicists and technicians was 9.2 h; 6.19 h; 7.2 h, respectively. The total number of afterloaders was 43 (22 HDR, 18 LDR, 3 PDR). The tumours most frequently treated with brachytherapy were gynaecological (56.24%), breast (14.2%) and prostate (11.7%). High dose rate was used in 47.46% of the patients and low dose rate in 47.24%. Between 1997 and 2002 there was an increase of 50.53% in patients treated with brachytherapy.

CONCLUSIONS

The survey shows the brachytherapy resources and activity in Spain up to 2003. Increased use of brachytherapy in prostate tumours, prevalence of gynaecology brachytherapy and similar number of treatments with HDR and LDR are demonstrated in the Patterns of Care of Brachytherapy in Europe (PCBE) study in Spain.

Emerging Technology and Practice: Characteristics of PET-CT Technologists

PURPOSE

The purpose of this study was to determine how many and which computed tomography (CT) scans are performed by technologists on positron emission tomography (PET)/CT fusion scanners.

MATERIALS AND METHODS

A survey of registrants was conducted by the American Registry of Radiologic Technologists (ARRT). The sample was selected on the basis of disciplines of employment, including nuclear medicine technology (NMT), CT, and fusion. Of 676 technologists with appropriate characteristics (eg, staff technologists), a random sample of 400 was selected. A total of 173 surveys were returned (43%), and 56 respondents were identified as PET-CT technologists.

RESULTS

Among PET-CT respondents (n = 56), 52% worked in community or university hospitals, 38% in free-standing centers, and 10% in mobile units. On the basis of the percentage of time (mean = 54%) and the number of patients per week (mean = 25), respondents spent most of their time in PET-CT or NMT. Of 53 CT-only procedures that form the ARRT's CT clinical experience requirements, 18 were identified as requirements respondents could fulfill (ie, they could be performed 3 to 5 times within a 24-month period). The average frequency of performance was at least 1 time in the past 6 months. Quality assurance procedures had higher endorsement rates (mean = 70%) and higher frequencies (mean = 1.7 times in 6 months). More than 35% of respondents could fulfill current CT clinical experience requirements.

CONCLUSIONS

Positron emission tomography/CT technologists are mainly performing fusion scans; CT-only scans are not widely performed by PET-CT technologists on fusion scanners; PET-only scans are also rare. Most of the CT-only tasks performed are quality assurance.

250,000 R.T.s

The ranks of R.T.s continue to grow and the demographics continue to evolve. The Registry is proud to say, "ARRT, a quarter of a million registered technologists, strong and growing!"

A conditional nonparametric test for comparing two areas under the ROC curves from a paired design

RATIONALE AND OBJECTIVES

To develop a conditional nonparametric procedure for comparing two correlated areas under receiver operating characteristic (ROC) curves (AUC).

MATERIALS AND METHODS

A nonparametric conditional test to compare areas under two ROC curves was developed using the distribution of the elements of the nonparametric AUC estimators in a permutation space. The conditioning is made on the observed discordances between the relative orderings of ratings of the normal and abnormal cases for the two modalities taken over all possible pairs. The type I error of the procedure was verified using computer simulations. The power of the test was compared with an existing unconditional procedure on simulated datasets from binormal distributions as well as from a mixture of binormal distributions of ratings.

RESULTS

The proposed test is conservative for low sample sizes, large AUC, and high correlation between modalities. It possesses a reasonable type I error for sample sizes as low as 20 actually positive and 20 actually negative cases. In plausible situations in which the sample in observer performance studies can not be monotonically transformed into a binormal distribution, this approach may have modest power advantages over the conventional nonparametric test.

CONCLUSION

The conditional nonparametric test presented here is an alternative approach to existing unconditional procedures and may offer advantages in certain types of observer performance studies.

Professional and economic factors affecting access to mammography: A crisis today, or tomorrow?

BACKGROUND

Objective data and anecdotal reports have suggested that access to mammography may be declining because of facility closures and difficulty in recruiting and retaining radiologists and radiologic technologists. To gain insight into the practice patterns, use of emerging technologies, and concerns of breast imagers in current practice, the Society of Breast Imaging (SBI) conducted a national survey of breast imaging practices in the U.S.

METHODS

Between October 2003 and April 2004, the SBI conducted a survey of the SBI membership database, and received completed surveys from 575 breast imaging practices in the U.S. Responses to the survey regarding practice characteristics, the utilization of standard and emerging technologies, staffing, malpractice, finance, and morale were analyzed.

RESULTS

Job vacancies for radiologists who read mammograms were reported in 163 practices (29%), 59 of which (10%) had 2 or more openings. A higher proportion of practices with job openings had long appointment waiting times for asymptomatic women when compared with fully staffed practices. Unfilled fellowship positions also were common, with 41 of 65 practices that offer fellowships reporting 47 openings. Among 554 responding practices, 55% reported that someone in their practice was sued because of a mammography related case within the past 5 years, and 50% of practices reported that the threat of lawsuits made radiologist staffing "moderately" or "a lot" more difficult. Of 521 responding practices, 35% reported financial losses in 2002. One in 5 respondents reported that they would prefer to spend less time in mammography, and fewer than 1 in 3 would recommend a breast imaging fellowship to a relative or friend. Emerging technologies, such as breast magnetic resonance imaging and screening ultrasound, currently are being performed in many practices.

CONCLUSIONS

The survey results provide support for anecdotal reports that breast imaging practices face significant challenges and stresses, including shortages of key personnel, a lack of trainees, malpractice concerns, financial constraints, increased workload due to emerging technologies, low appeal of breast imaging as a career specialty, and the steady rise in the population of women of screening age.

Accuracy of the Burns equation for stopping-power ratio as a function of depth and R50

The accuracy of the Burns et al. equation [Med. Phys. 23, 489-501 (1996)] for the Spencer-Attix water to air stopping-power ratio as a function of depth in a water phantom and electron beam quality in terms of R50 is investigated by comparison to the original data on which this fit was based. It is shown that using this equation provides dose estimates on the central axis in a clinical electron beam that are accurate to within 1% of dose maximum for all 24 clinical beams investigated except very close to the surface in swept beams. In contrast, the error in the dose as a percentage of the local dose is much higher for values of the depth/R50 greater than 1.2.

Cancer incidence in the US radiologic technologists health study, 1983-1998

BACKGROUND

Workers exposed to low doses of radiation can provide information regarding cancer risks that are of public concern. However, characterizing risk at low doses requires large populations and ideally should include a large proportion of women, both of which rarely are available.

METHODS

Among 90305 radiologic technologists in the U.S. (77% women) who were followed during 1983-1998, data concerning incident cancer occurrence was obtained from mailed questionnaires and from death records. Standardized incidence ratios (SIRs) were computed using age-specific, gender-specific, race-specific, and calendar year-specific cancer rates from the Surveillance, Epidemiology, and End Results Program.

RESULTS

The SIR for all cancers in both genders combined was 1.04 (95% confidence interval [95% CI], 1.00-1.07; n = 3292 technologists). Female technologists had an elevated risk for all solid tumors combined (SIR = 1.06; 95% CI, 1.02-1.10; n = 2168 women) and for breast cancers (SIR = 1.16; 95% CI, 1.09-1.23; n = 970 women), melanoma (SIR = 1.66; 95% CI, 1.43-1.89; n = 181 women), and thyroid cancers (SIR = 1.54; 95% CI, 1.24-1.83; n = 107 women). Male technologists experienced a decreased risk for solid tumors (SIR = 0.92; 95% CI, 0.85-0.98; n = 755 men); however, melanoma (SIR = 1.39; 95% CI, 1.00-1.79; n = 56 men) and thyroid cancers (SIR = 2.23; 95% CI, 1.29-3.59; n = 17 men) were increased. Among both genders, the risks were decreased for buccal cavity/pharyngeal cancers (SIR = 0.73; 95% CI, 0.55-0.90; n = 54 technologists), rectal cancers (SIR = 0.62; 95% CI 0.48-0.76; n = 53 technologists), and lung cancers (SIR = 0.77, 95% CI, 0.70-0.85; n = 307 technologists).

CONCLUSIONS

The elevated risk for breast cancer may have been related to occupational radiation exposure. The observed excesses of melanoma and thyroid cancers may reflect, at least in part, earlier detection among medical workers with easy access to health care.

Research and scholarship among R.T. educators

Full-time registered radiologic technologist educators were surveyed to determine their professional profile and research/scholarship productivity. Overall, research and scholarship productivity was low. More than 85% of respondents had not authored an article in a peer or nonpeer-reviewed journal, although more than half of the sample reported other scholarly activities, such as reviewing books, developing continuing education material and presenting at professional meetings. As a group, full-time educators employed in 4-year institutions and holding a higher academic degree were more productive in research and scholarship.

Interactions with 3D isotropic and homogeneous radiation fields: a Monte Carlo simulation algorithm

Monte Carlo techniques have become important tools for many biomedical applications. Many of these involve simulations of radiation fields that rely on the isotropy and homogeneity of the radiation source. The current study proposes a general algorithm to simulate such a radiation field around a fixed object. The idea is to surround the object with a sphere and to limit the source of radiation to the surface of that sphere. To insure the isotropy of the radiation source, each point on the sphere surface as seen from the object defines a direction at which a unidirectional field of particles is created. The combination of all unidirectional fields approaching from all points on the source sphere creates the effect of an isotropic and homogeneous radiation source. The algorithm is first presented without mathematical detail. Next, the expressions for the position and direction of the particles that compose the field are derived using analytical geometry. The radius of the source sphere is the only parameter needed for this algorithm. The randomness of each particle is simulated by the choice of four random numbers. Two algorithms using these analytical results are proposed, and an example of a C program is given for each. Both algorithms can be easily adapted to any situation that involves the Monte Carlo simulation of radiation interactions of a fixed object immersed within an isotropic and homogeneous radiation field.

Precise image-receptor calibration and monitoring of beam quality with a step wedge

OBJECTIVE

To describe an extended bootstrap calibration procedure that uses a step-wedge absorber and minimal equipment for rapid, accurate calibration of image receptors and simultaneous monitoring of beam quality.

METHODS

Multiple radiographs of a step wedge are made at different exposures, with a precision dosimeter as a reference. An iterative least-squares minimization procedure is used to fit the data with a single calibration function. The calibration range can be extended by varying two exposure parameters in addition to stepwedge thickness. Small variations in beam quality and other experimental artifacts can be detected by testing redundant data for self-consistency. As a demonstration, two photostimulable phosphor (PSP) systems were calibrated, one with a well-regulated X-ray source and the other with a poorly regulated source.

RESULTS

The first PSP system was calibrated over a range of 3.2 orders of magnitude with a relative standard deviation of the estimate of only 0.36%. The slope of the calibration curve agreed with the nominal, factory-set value within 0.8% (on a logarithmic scale). The second PSP system had a nearly linear response with a relative standard deviation of the estimate of 0.44% over the upper 97% of its range. Both X-ray sources showed easily detectable variations in tube potential.

CONCLUSIONS

The new calibration method eliminates many of the sources of error of previous techniques such as inverse-square sensitometry. If a suitably precise X-ray source is available, the relative accuracy is limited only by the precision of the receptor system.

An analysis of managerial skills for the current and future health care environment

A survey questioned 503 experienced practitioners about managerial tasks and responsibilities of senior professionals in four allied health fields: physiotherapy, speech-language pathology, occupational therapy, and medical radiation science. Participants worked in a range of settings, including the private and public sectors, small and large departments/units, and community and hospital-based work sites. Factor analysis identified eight managerial areas of functioning: department running, staff relations management, legislative knowledge, career path management, implementation and change, quality assurance, management of future planning, and prioritizing work. The professional field of the practitioner influenced the importances attached to these areas, while work setting and gender of practitioner had minimal impact. Level of involvement in managerial tasks had no bearing on the importance attached to competency areas. Open-ended comments added depth to the results of the factor analysis. The findings are discussed with respect to the changing requirements being placed upon health service personnel.

Design of a dual CCD configuration to improve the signal-to-noise ratio

The noise of a digital charge coupled device (CCD) detector increases with the readout speed, causing problems in a number of important applications, such as x-ray fluoroscopy and micro-CT. In this paper, we present an approach for the design of a dual-CCD configuration to improve the average signal-to-noise ratio, and hence provide an inexpensive solution within the constraint of the current technology.

[Cohen's kappa or McNemar's test? A comparison of binary repeated measurements]

This article intends to illustrate the combination of McNemar's significance test and Cohen's kappa coefficient in the comparison of repeated binary measurements. Both methods are standard statistical tools of major relevance for the evaluation and comparison of clinical imaging methods and thus have an impact on the corresponding publications. The interpretation of results obtainable with these methods will be illustrated to facilitate their use based on recent statistical software. Examples will further outline limitations and possible pitfalls in their application to clinical data.