Fluoroscopy X-Ray Organ-Specific Dosimetry System (FLUXOR) for Estimation of Organ Doses and Their Uncertainties in the Canadian Fluoroscopy Cohort Study

As part of ongoing efforts to assess lifespan disease mortality and incidence in 63,715 patients from the Canadian Fluoroscopy Cohort Study (CFCS) who were treated for tuberculosis between 1930 and 1969, we developed a new FLUoroscopy X-ray ORgan-specific dosimetry system (FLUXOR) to estimate radiation doses to various organs and tissues. Approximately 45% of patients received medical procedures accompanied by fluoroscopy, including artificial pneumothorax (air in pleural cavity to collapse of lungs), pneumoperitoneum (air in peritoneal cavity), aspiration of fluid from pleural cavity and gastrointestinal series. In addition, patients received chest radiographs for purposes of diagnosis and monitoring of disease status. FLUXOR utilizes age-, sex- and body size-dependent dose coefficients for fluoroscopy and radiography exams, estimated using radiation transport simulations in up-to-date computational hybrid anthropomorphic phantoms. The phantoms include an updated heart model, and were adjusted to match the estimated mean height and body mass of tuberculosis patients in Canada during the relevant time period. Patient-specific data (machine settings, exposure duration, patient orientation) used during individual fluoroscopy or radiography exams were not recorded. Doses to patients were based on parameter values inferred from interviews with 91 physicians practicing at the time, historical literature, and estimated number of procedures from patient records. FLUXOR uses probability distributions to represent the uncertainty in the unknown true, average value of each dosimetry parameter. Uncertainties were shared across all patients within specific subgroups of the cohort, defined by age at treatment, sex, type of procedure, time period of exams and region (Nova Scotia or other provinces). Monte Carlo techniques were used to propagate uncertainties, by sampling alternative average values for each parameter. Alternative average doses per exam were estimated for patients in each subgroup, with the total average dose per individual determined by the number of exams received. This process was repeated to produce alternative cohort vectors of average organ doses per patient. This article presents estimates of doses to lungs, female breast, active bone marrow and heart wall. Means and 95% confidence intervals (CI) of average organ doses across all 63,715 patients were 320 (160, 560) mGy to lungs, 250 (120, 450) mGy to female breast, 190 (100, 340) mGy to heart wall and 92 (47, 160) mGy to active bone marrow. Approximately 60% of all patients had average doses to the four studied organs of less than 10 mGy, 10% received between 10 and 100 mGy, 25% between 100 and 1,000 mGy, and 5% above 1,000 mGy. Pneumothorax was the medical procedure that accounted for the largest contribution to cohort average doses. The major contributors to uncertainty in estimated doses per procedure for the four organs of interest are the uncertainties in exposure duration, tube voltage, tube output, and patient orientation relative to the X-ray tube, with the uncertainty in exposure duration being most often the dominant source. Uncertainty in patient orientation was important for doses to female breast, and, to a lesser degree, for doses to heart wall. The uncertainty in number of exams was an important contributor to uncertainty for ∼30% of patients. The estimated organ doses and their uncertainties will be used for analyses of incidence and mortality of cancer and non-cancer diseases. The CFCS cohort is an important addition to existing radio-epidemiological cohorts, given the moderate-to-high doses received fractionated over several years, the type of irradiation (external irradiation only), radiation type (X rays only), a balanced combination of both genders and inclusion of people of all ages.

Low Radiation X-rays: Benefiting People Globally by Reducing Cancer Risks

Modern medical imaging facilitates the diagnosis and treatment of human diseases. However, few people are aware of the cons of radiation exposure from medical imaging. Emerging evidence reveals that cumulative doses of radiation exposure will increase the morbidity and mortality of pertaining cancer. As a special young population, patients with adolescent idiopathic scoliosis (AIS) suffer more radiation harms from repeated diagnostic imaging, most of which can be avoided in clinical practice. Accumulating evidence highlights reduced cancer risks of radiation exposure for AIS patients with low/zero radiation imaging modalities proposed, amongst which easy conversion from anterior-posterior (AP) to posterior-anterior (PA) projection for whole-spine radiographs should be stressed. It can greatly reduce radiation doses without compromising the quality of diagnostic imaging. Tight collimation combined with PA projection can further reduce radiation harms, and need to be spread to benefit people globally.

Cost-risk-benefit analysis in diagnostic radiology with special reference to the application of referral guidelines

Cost-risk-benefit analysis has been applied to protection of the patient in diagnostic radiology with special reference to the application of referral guidelines. The analysis presented has extended previous work in this field to provide a theoretical framework that encompasses key factors that need to be considered in the optimisation of patient protection from both diagnostic and radiation risks. The fraction of patients whose symptoms do not meet criteria contained in the referral guidelines and, therefore, for whom an X-ray examination is not indicated has been termed the selectivity of the guidelines. Also included are the detriments arising from rejected or repeated examinations as well as the levels of patient dose employed in order to achieve given levels of true and false diagnostic outcomes. A comprehensive framework for optimisation is outlined and its relationship to justification discussed.

Clinical Biomarkers for Diagnosis of Damages in Individuals with Long-Term Exposure to X-Rays

OBJECTIVE

To determine altered manifestation of plasma proteins in X-rays technicians who are regularly exposed to low doses of radiations over a long period during their job.

STUDY DESIGN

Descriptive study.

PLACE AND DURATION OF STUDY

District Headquarters Hospital and Mufti Mahmood Memorial Teaching Hospital; from January 2017 to January 2018.

METHODOLOGY

The study enrolled 70 individuals consisting of 50 X-ray technicians working 8 to 12 hours/day for five days per week and 20 unexposed healthy controls. The serum protein expression pattern (concentrations of various serum proteins) was evaluated through cellulose acetate electrophoresis and serum antioxidant status was measured through ferric reducing ability of plasma (FRAP) assay.

RESULTS

The antioxidant assay showed significantly low trolox-equivalent antioxidant capacity (TEAC) status and FRAP value in X-ray technicians as compared to controls (p<0.001). Analysis of serum protein demonstrated a significantly reduced concentrations of albumin (p<0.001) and elevated level of the Ɣ-globulins (p<0.001), while other globulins fractions like α1 and β remain unchanged. There was a strong negative correlation (p<0.001) according to Pearson coefficient (r=87%⁽⁻⁾) between albumin and Ɣ-globulins fraction. Whereas, a positive correlation (p<0.001) (r=46%⁽⁺⁾) between alpha 1 globulin and albumin fraction was observed. A correlation between other globulin fractions and albumin was found statistically significant (p<0.001).

CONCLUSION

Elevated serum gamma globulins may be a potential protein biomarker for triage and detection of X-radiation induced damages.

Alfred Caleb Taylor (1860-1927): X-ray pioneer and martyr

Alfred Caleb Taylor was the first radiographer at the Peterborough Infirmary and Dispensary from 1896 to 1923. He constructed the first X-ray apparatus and oversaw the development of the X-ray service in Peterborough. He contracted a chronic radiation dermatitis from exposure to X-rays which was a source of considerable suffering for him. When he died in 1927, X-ray dermatitis was considered to have contributed to his death, and he was recognised as an X-ray martyr and a victim of science. In spite of his achievements and his ill-health from working with X-rays, his name is not included on the Martyrs Memorial in Hamburg.

LINE-1 hypomethylation is associated with radiation-induced genomic instability in industrial radiographers

Global DNA hypomethylation is proposed as a potential biomarker for cancer risk associated with genomic instability, which is an important factor in radiation-induced cancer. However, the associations among radiation exposure, changes in DNA methylation, and carcinogenesis are unclear. The aims of this study were (1) to examine whether low-level occupational radiation exposure induces genomic DNA hypomethylation; and (2) to determine the relationships between radiation exposure, genomic DNA hypomethylation and radiation-induced genomic instability (RIGI) in industrial radiographers. Genomic DNA methylation levels were measured in blood DNA from 40 radiographers and 28 controls using the LINE-1 pyrosequencing assay and the luminometric methylation assay. Further, the micronucleus-centromere assay was performed to measure aneuploidy of chromosomes 1 and 4 as a marker of delayed RIGI. Genomic DNA methylation levels were significantly lower in radiographers than those in controls. LINE-1 hypomethylation was not significantly correlated with recent 1-year, recent 3-year, or total cumulative radiation doses in radiographers; however, LINE-1 hypomethylation significantly correlated with the cumulative radiation dose without recent 3-year exposure data (D3dose, r = -0.39, P < 0.05). In addition, LINE-1 hypomethylation was a significant contributor to aneuploidy frequency by D3dose (F (2, 34) = 13.85, P < 0.001), in which a total of 45% of the variance in aneuploidy frequency was explained. Our results provide suggestive evidence regarding the delayed effects of low-dose occupational radiation exposure in radiographers and its association with LINE-1 hypomethylation; however, additional studies using more subjects are needed to fully understand the relationship between genomic DNA hypomethylation and RIGI. Environ. Mol. Mutagen. 60: 174-184, 2019. © 2018 Wiley Periodicals, Inc.

Patient Perspectives on Dialogue and Shared Decision Making

The fear of radiation on the part of patients and/or clinical staff can hamper adequate shared medical decision making. Typically, one-sided medical radiation risk communication methods with limited effectiveness are employed, such as paternalistic, risk numerology, and quality "assurance" approaches. More study is needed to determine patient preferences and potential fears associated with medical imaging radiation, and the results can provide insights for such discussions. Worry about the potential risks associated with medical imaging radiation has been shown to be substantial in the US population. The level of concern differs by sex, race/ethnicity, education, nationality, and overall health, suggesting that more care and individualized communication and discussion methods need to be employed by clinical staff. The opportunities for improved dialogue with patients (and parents of patients) and the public in general are plentiful.

Quality and Safety Initiatives for Radiation Safety in Imaging

There is a substantial infrastructure for quality and safety in radiologic imaging, built over decades, that is available to practices and providers. The purpose of this review is to provide an overview of those resources and place them in the context of patient care. Successful application of these resources requires both the technology as well as the culture to use the techniques. We are beginning to see more tools to support the culture change necessary to take advantage of the resources, and increased attention to the patient perspective.

Benefits and Risks in Medical Imaging

Ionizing radiation has contributed enormously to dramatic improvements in medical care. The potential risks of radiation-based medical imaging have, however, drawn considerable attention in recent years. Although such concern is beneficial in terms of critical evaluation and optimization of imaging procedures, it can create the misconception that radiation is the only risk of medical imaging. In contrast to expression of radiation risks, quantitative estimates of the benefits of medical imaging are notably lacking. Expression of benefit in purely qualitative terms vs. expression of risk in quantitative, and thus apparently more concrete, terms may contribute to a biased judgement of the relative benefits and risks of medical imaging among health care professionals as well as the public. This paper, therefore, quantitatively compares the benefits of diagnostic imaging in several cases, based on actual mortality or morbidity data if ionizing radiation were not employed, with the linear no-threshold model derived (i.e., theoretical) estimates of radiogenic cancer mortality and illustrates the large benefit-to-risk ratios typical of medical imaging procedures.

Uses of Effective Dose: The Good, the Bad, and the Future

Effective dose (E) is a risk-adjusted dosimetric quantity developed by the International Commission on Radiological Protection. It is a key metric for practical management of the risk of stochastic health effects in a comprehensive radiation protection program. The International Commission on Radiological Protection and others have emphasized repeatedly that E is not intended to represent an actual radiation dose and should not be used as a risk-related metric for a specific person or population. The cancer risk uncertainties in the low-dose range and the underlying approximations, simplifications, and sex- and age-averaging used in generating E make it unsuitable for this purpose. However, in practice, medical imaging professionals and authors of peer-reviewed medical publications frequently and incorrectly use E as a surrogate for whole-body dose in order to calculate cancer risk estimates for specific patients or patient populations. This frequent misuse has popularized E for uses for which it was neither designed nor intended. Alternatives to E have been proposed that attempt to account for known age and sex differences in radiation sensitivity. E has also been proposed as a general indicator for communicating radiation risk to patients, if its limitations are kept in mind. Forthcoming guidance from the International Commission on Radiological Protection will likely clarify if, when, and how some form of E may be used as a rough indicator of the risk of a stochastic effect, possibly with some modifications for the substantial variations in risk known to exist with respect to age, sex, and population group.

Increased radiation dose and projected radiation-related lifetime cancer risk in patients with obesity due to projection radiography

PURPOSE

Primarily to evaluate the radiation dose delivered to patients with obesity in projection radiography and its relationship to the patient's size. A secondary purpose is to estimate the subsequent projected radiation-related lifetime cancer risk to patients with obesity compared to normal-weight patients.

METHOD AND MATERIAL

Data from 1964 patients from a bariatric clinic in the UK were reviewed with the relevant permission. 630 patients were identified to have a projection radiography history and were included in the study. Patients' dose area product (DAP) data were collected for all projection radiography. Multiple exams in one day including a single DAP reading and exams with no records of DAP and exposure factors were excluded. Correlations were calculated and data analysed to yield the third quartile for each examination using STATA 14. Absorbed doses were generated from PCXMC simulation, utilising DAP data from this study and the UK national diagnostic reference level (NDRL), to calculate the effective risk for patients with obesity compared to patients with normal-weight.

RESULTS

Patients with obesity received higher DAPs for all examinations included in this study compared to NDRL. Abdominal and lumbar spine radiographs DAPs were the highest (17.6 and 30.31 Gy cm²) compared to the NDRL (2.5 and 4 Gy cm²). Only moderate to low correlations were found between patient's size and DAPs in the abdomen and chest radiographs. The projected radiation-related lifetime cancer risk for patients with obesity is up to 153% higher than for adult patients with normal weight.

CONCLUSION

Patients with obesity receive higher DAPs than normal-weight adults which may be in excess of that expected due to their size. Therefore, radiation-related lifetime cancer risk is increased in patients with obesity as a result of medical radiation exposures. This indicates more dose optimisation research is needed in this group of patients to reduce dose rate and variation.

Estimation of the effects of medical diagnostic radiation exposure based on DNA damage

X-rays are widely applied in the medical field for the diagnosis and treatment of diseases. Among the uses of X-rays in diagnosis, computed tomography (CT) has been established as one of the most informative diagnostic radiology examinations. Moreover, recent advances in CT scan technology have made this examination much easier and more informative and increased its application, especially in Japan. However, the radiation dose of CT scans is higher than that of simple X-ray examinations. Therefore, the health risk of a CT scan has been discussed in various studies, but is still controversial. Consequently, the biological and cytogenetic effects of CT scans are being analyzed. Here, we summarize the recent findings concerning the biological and cytogenetic effects of ionizing radiation from a CT scan, by focusing on DNA damage and chromosome aberrations.

Work environment and occupational risk assessment for small animal Portuguese veterinary activities

The professional work of small animal veterinary staff encompasses a wide diversity of demanding tasks. This has prompted a number of studies covering physical, chemical, biological, ergonomic, or psychological hazards, as well as their health effects upon veterinary workers. However, such results were obtained from self-reported surveys (via paper or online). This study reports the identification of potential hazards and provides a risk assessment of 15 veterinary clinics based on data from walk-through surveys, interviews with workers, and quantification of indoor air quality parameters including concentration of volatile organic compounds (total, isoflurane, and glutaraldehyde). The risk arising from X-ray exposure was unacceptable in seven clinics; X-ray examination should be discontinued in the absence of isolated radiation rooms, poor safety practices, and lack of personal protective equipment. Ergonomic-related hazards and work practices should be revised as soon as possible, considering that improper postures, as well as moving and lifting heavy animals are major causes of musculoskeletal disorders. The risk levels were, in general, small or medium (acceptable) with regard to exposure to physical hazards (such as bites, scratches, cuts, and burns) and biological hazards. It was observed that the indoor air quality parameters including temperature, respirable particulate matter and total volatile organic compounds do not indicate a comfortable workplace environment, requiring clinics' attention to keep the safe environment. The veterinarians and nurses were exposed to isoflurane (above 2 ppm) during surgery if an extractor system for waste gas was used instead of a scavenging system. Finally, veterinary workers did not possess any type of training on occupational safety and health issues, even though they recognized its importance.

Estimation of the occupational exposure dose for medical diagnostic X-ray workers in Jiangsu, China, using a retrospective dosimetry method

Medical diagnostic X-ray workers are one occupational group that has exposure to continuous low doses of external radiation over their working lifetimes. Current ICRP recommendations [ICRP. Recommendations of the International Commission on Radiological Protection. ICRP Publication 60. Ann ICRP 1991;21 (1-3)] state that there is no threshold of stochastic effects induced by radiation exposure such as carcinogenicity or genetic defects, and that the frequency of the effects is proportional to the amount of exposure to low levels of radiation, which is measured by radiation dose. In order to determine the dose information for this special occupational group over their working lifetimes (focusing particularly on workers exposed before 1985, when there was no personal dose monitoring), a sampling survey of the occupational history for these workers was conducted and an occupational history database was established. Using the database and retrospective dosimetry method of Zhang et al. (A retrospective dosimetry method for occupational dose for Chinese medical diagnostic X-ray workers. Radiat Prot Dosimetry 1998;77:69-72), the annual occupational exposure dose for medical diagnostic X-ray personnel working between 1950 and 2011 was computerized. Some annual dose results estimated using the proposed method were numerically in good agreement with the monitoring results. The average of the annual dose for these medical workers peaked during the mid-1950s and then declined, reaching very low levels by the 1990s and remaining at those levels thereafter. The trend in the annual dose is similar to that reported by earlier studies by Zielinski et al. (Health outcomes of low-dose ionizing radiation exposure among medical workers: a cohort study of the Canadian national dose registry of radiation workers. Int J Occup Med Environ Health 2009;22:149-56). The dose calculated by the retrospective dosimetry method can truly indicate the degree of the workers' exposure in their medical X-ray diagnostic work.

Diagnostic X-Ray Exposure and Thyroid Cancer Risk: Systematic Review and Meta-Analysis

BACKGROUND

Radiation exposure is a well-known risk factor for thyroid cancer. However, the specific effects of diagnostic radiation exposure on thyroid cancer risk are controversial. The purpose of this study was to perform a systematic review and meta-analysis to assess the effects of diagnostic radiation exposure on thyroid cancer risk.

METHODS

The PubMed and EMBASE databases were searched to identify eligible studies. Summary odds ratio (OR) estimates and confidence intervals (CIs) were used to compute the risk of thyroid cancer using fixed- and random-effects models. Subgroup and sensitivity analyses were performed to evaluate the potential heterogeneity.

RESULTS

Nine studies from 12 publications were included in the meta-analysis. Overall exposure to diagnostic radiation exposure was associated with a significantly increased thyroid cancer risk (OR = 1.52 [CI 1.13-2.04]). The subgroup and sensitivity analyses revealed similar results. By type of exposure, exposure to computed tomography scans (OR = 1.46 [CI 1.27-1.68]) or dental x-rays (OR = 1.69 [CI 1.17-2.44]) were associated with an increased thyroid cancer risk. Head and neck (OR = 1.31 [CI 1.02-1.69]) and chest (OR = 1.71 [CI 1.09-2.69]) exposure to diagnostic radiation was associated with an increased thyroid cancer risk.

CONCLUSIONS

The results of this meta-analysis indicate that diagnostic radiation exposure is associated with an increased thyroid cancer risk. Therefore, to the extent that it will not compromise the information being sought, radiation exposure to the thyroid should be minimized during diagnostic examinations.

[THE DETERMINATION OF EFFECTIVE EQUIVALENT DOSES DURING CHEST RADIOLOGY IN PATIENTS]

As is known, medical radiation has a big impact on the increase of population doses, which determines the risk of increasing population's radiation. Thus, it is relevant the determination of the radiation doses in patients during X-ray diagnostic procedures up to now. The aim of our research is the examination of the effective equivalent doses and their determination during X-ray. Due to the experimental modeling method by using phantom and TLD it has been determined average absorbed doses in separate organs of patients, also the effective equivalent dose during chest organs radiology, which is 122 mrem. It has been relieved that numerical index of the effective equivalent dose was significantly different from consistent inputted exposure and superficial dose indexes, that where often used for the assessment of radiation risk in patients, HE is eight times different from the corresponding value of EED, which amounted to about 1400mR per 1000 mR of EED. It has been established that on "other" organs (on the liver and gastrointestinal tract) the radiation has a big importance for the whole organism radiation exposure in the total effect. The protection of these organs is advisable in every cases, if they are the research object of X-ray or not. Additionally, the contribution of "other" organs is not less than lung lobes, which do not present the research object of X-ray. It has been established the prospects of computing methods due to conducted studies for the determination of the effective equivalent dose in patients for the assessment of X-ray radiation risk.

Clinical perspective on diagnostic X-ray examinations of pregnant patients - What to take into account

Imaging during pregnancy has increased in frequency. Radiation protection is extremely important although tissue reactions of the conceptus, requiring a threshold dose of around 100mGy, are unlikely in the diagnostic use of X-rays and stochastic effects of cancerogenesis have a rather low risk (around 10^-4/mGy for childhood cancer due to in utero exposure). This article will review the risk depending on dose and phase of pregnancy and the exposure by frequent examinations; it will then concentrate on the duties of an imaging department: screening for pregnancy, examination justification, planning and optimization, patient information, counseling, involving the patient in the decisions, and managing the situation of pregnant staff members. Typical flowcharts of investigating frequent clinical questions will finally be presented and critically discussed.

Pediatric Exposures to Ionizing Radiation: Carcinogenic Considerations

Children are at a greater risk than adults of developing cancer after being exposed to ionizing radiation. Because of their developing bodies and long life expectancy post-exposure, children require specific attention in the aftermath of nuclear accidents and when radiation is used for diagnosis or treatment purposes. In this review, we discuss the carcinogenic potential of pediatric exposures to ionizing radiation from accidental, diagnostic, and therapeutic modalities. Particular emphasis is given to leukemia and thyroid cancers as consequences of accidental exposures. We further discuss the evidence of cancers that arise as a result of radiotherapy and conclude the review with a summary on the available literature on the links between computer tomography (CT) and carcinogenesis. Appropriate actions taken to mitigate or minimize the negative health effects of pediatric exposures to ionizing radiation and future considerations are discussed.

Consecutive results of blood cell count and retrospective biodosimetry: useful tools of health protection regulation for radiation workers

BACKGROUND

Industrial radiography is known to be one of the most vulnerable lines of work among the range of different radiation work. According to the relevant law in Korea, every worker registered in this work should check their blood cell counts every year in addition to their thermoluminescent dosimeter (TLD) doses. Since the law was enacted, however, few follow-up studies have been carried out based on the obtained results.

OBJECTIVES

To ascertain the clinical usefulness of complete blood cell count (CBC) results and suggest a proper protocol of health protection for radiation workers.

METHODS

After reviewing all the consecutive results of CBC and TLD doses from radiation workers registered nationwide, we selected two groups of high-risk radiation workers, CBC-high risk (CBC-HR) and TLD-high risk (TLD-HR) groups. A control group of unexposed healthy adults was also included. We compared the absorbed doses calculated by cytogenetic biodosimetry among those three groups, and examined possible confounding factors for each group.

RESULTS

Both groups of high-risk radiation workers, CBC-HR and TLD-HR, showed higher chromosome aberrations than the control group. In the control group, previous medical history of a CT scan increased the frequency of chromosome aberrations. In contrast, the frequency of chromosome aberrations in the high-risk radiation workers was affected not by the previous CT history but only by the duration of their work.

CONCLUSIONS

We ascertain that reviewing consecutive results of blood cell counts and cytogenetic biodosimetry are useful complementary tools to TLD doses for health protection regulation. Several confounding factors including work duration and previous medical history need to be considered for the interpretation of biodosimetry results.

EXPOSURE OF THE SWISS POPULATION BY RADIODIAGNOSTICS: 2013 REVIEW

In 2013, a nationwide investigation was conducted in Switzerland to establish the population's exposure from medical X rays. A hybrid approach was used combining the Raddose database accessible on-line by the participating practices and the Swiss medical tariffication system for hospitals. This study revealed that the average annual number of examinations is 1.2 per inhabitant, and the associated annual effective dose is 1.4 mSv. It also showed that computed tomography is the most irradiating modality and that it delivers 70 % of the total dose. The annual effective dose per inhabitant registered a 17 % increase in 5 y and is comparable with what was recently reported in neighbouring countries.

A root cause analysis of the high occupational doses of industrial radiographers in Iran

The Iran Nuclear Regulatory Authority has investigated overexposure cases in industrial radiography over a period of three years. Radiographers with thermoluminescence dosimeter (TLD) records of more than 4 mSv in any 2 month routine monitoring period were asked to fill in a questionnaire explaining their points of view of the reasons for such relatively high doses. The responses showed that more than 50% of the radiographers did not agree with their recorded TLD doses, although the majority of the alternative explanations were weak. The main causes of overexposures were found to be difficult working conditions and ignoring safety principles while accidents or device failures were a minor contribution. Also, there was poor correlation between the TLDs and direct reading dosimeters worn by the radiographers, indicating that personal monitoring instructions were not being implemented appropriately.

Evaluating the Radiation From Accidental Exposure During a Nondestructive Testing Event

Industrial radiography is a common nondestructive testing (NDT) method used in various industries. An investigation was conducted for a 1999 incident in Taiwan where two workers (Operators A and B) were accidently exposed to an unshielded Ir source while conducting industrial radiography. Operators A and B experienced acute close-range radiation exposure to a source of Ir for 3 h at a strength of 2.33 × 10 Bq. The health of mammary glands, bone marrow, thyroid glands, eyes, and genital organs of these two workers after radiation exposure was examined. Subsequently, Operator A experienced severe radiation injury, including tissue necrosis and keratinization in the fingers, chromosomal abnormalities, reduced blood cell count, diffuse hyperplasia of the thyroid gland, opaque spots in the crystalline lens, and related radiation effects. The results showed that the left index finger and thumb, eyes, and gonads of Operator A were exposed to a radiation dose of about 369-1,070, 23.1-67.4, 2.4-5.3, and 4.2-11.6 Gy, respectively. Effective dose for Operator A was estimated to range from 6.9 to 18.9 Sv. The left fingers, thumb, eyes, and gonads of Operator B were exposed to a radiation dose of 184.9-646.2, 11.8-40.7, 0.49-3.33, and 0.72-7.18 Gy, respectively, and his effective dose was between 2.5 and 11.5 Sv. This accident indicated a major flaw in the control and regulation of radiation safety for conducting NDT industrial radiography in 1999; however, similar problems still exist. Modifications of the Ionizing Radiation Protection Act in Taiwan are suggested in this study to regulate the management of NDT industries, continually educate the NDT workers in radiation safety, and enact notification provisions for medical care systems toward acute radiation exposure events.

Imaging Radiation Doses and Associated Risks and Benefits in Subjects Participating in Breast Cancer Clinical Trials

BACKGROUND

Medical imaging is commonly required in breast cancer (BC) clinical trials to assess the efficacy and/or safety of study interventions. Despite the lack of definitive epidemiological data linking imaging radiation with cancer development in adults, concerns exist about the risks of imaging radiation-induced malignancies (IRIMs) in subjects exposed to repetitive imaging. We estimated the imaging radiation dose and IRIM risk in subjects participating in BC trials.

MATERIALS AND METHODS

The imaging protocol requirements in 10 phase III trials in the adjuvant and advanced settings were assessed to estimate the effective radiation dose received by a typical and fully compliant subject in each trial. For each study, the excess lifetime attributable cancer risk (LAR) was calculated using the National Cancer Institute's Radiation Risk Assessment Tool, version 3.7.1. Dose and risk calculations were performed for both imaging intensive and nonintensive approaches to reflect the variability in imaging performed within the studies.

RESULTS

The total effective imaging radiation dose was 0.4-262.2 mSv in adjuvant trials and 26-241.3 mSv in metastatic studies. The dose variability resulted from differing protocol requirements and imaging intensity approaches, with computed tomography, multigated acquisition scans, and bone scans as the major contributors. The mean LAR was 1.87-2,410/100,000 in adjuvant trials (IRIM: 0.0002%-2.41% of randomized subjects) and 6.9-67.3/100,000 in metastatic studies (IRIM: 0.007%-0.067% of subjects).

CONCLUSION

IRIMs are infrequent events. In adjuvant trials, aligning the protocol requirements with the clinical guidelines' surveillance recommendations and substituting radiating procedures with equivalent nonradiating ones would reduce IRIM risk. No significant risk has been observed in metastatic trials, and potential concerns on IRIMs are not justified.

IMPLICATIONS FOR PRACTICE

Medical imaging is key in breast cancer (BC) clinical trials. Most of these procedures expose patients to ionizing radiation, and the risk of second cancer development after imaging has prompted recent concerns and controversy. Using accepted calculation models, the number of malignancies were estimated that were potentially attributable to the imaging procedures performed during a patient's participation in BC clinical trials. The results show that for patients participating in metastatic trials, the risk of imaging radiation-induced malignancies is negligible. In adjuvant trials, some second cancers due to imaging could be expected, and measures can be taken to reduce their risk.

Manipulation of projection approach in pediatric radiography

PURPOSE

To determine whether manipulating routine projections from anteroposterior (AP) to posteroanterior (PA) during projection radiography studies will result in reduced pediatric radiation exposure.

METHOD

A literature analysis was conducted on pediatric radiation exposure, radiation protection, and tissue weighting factors. Multiple quantitative datasets were used to support findings related to projection manipulation.

RESULTS

Dosimetric studies confirm that the PA projection significantly decreases radiation exposure to nearly all radiosensitive tissue, with the exception of the patient's bone marrow.

DISCUSSION

Pediatric patients are inherently more sensitive to ionizing radiation, making this patient population a major focus of dose-reduction issues. Radiologic technologists are charged with keeping dose as low as reasonably achievable (following the ALARA principle), and performing PA projections rather than routine AP projections might decrease radiation to the pediatric population.

CONCLUSION

The PA projection results in a definitive reduction in radiation exposure to the majority of radiosensitive organs and tissues and should be considered for implementation on a routine basis.

Medical radiation exposure and human carcinogenesis-genetic and epigenetic mechanisms

Ionizing radiation (IR) is a potential carcinogen. Evidence for the carcinogenic effect of IR radiation has been shown after long-term animal investigations and observations on survivors of the atom bombs in Hiroshima and Nagasaki. However, IR has been widely used in a controlled manner in the medical imaging for diagnosis and monitoring of various diseases and also in cancer therapy. The collective radiation dose from medical imagings has increased six times in the last two decades, and grow continuously day to day. A large number of evidence has revealed the increased cancer risk in the people who had frequently exposed to x-rays, especially in childhood. It has also been shown that secondary malignancy may develop within the five years in cancer survivors who have received radiotherapy, because of IR-mediated damage to healthy cells. In this article, we review the current knowledge about the role of medical x-ray exposure in cancer development in humans, and recently recognized epigenetic mechanisms in IR-induced carcinogenesis.

Higher bone turnover is related to spinal radiographic damage and low bone mineral density in ankylosing spondylitis patients with active disease: a cross-sectional analysis

Introduction

Ankylosing spondylitis (AS) is characterized by excessive bone formation and bone loss. Our aim was to investigate the association of bone turnover markers (BTM) with spinal radiographic damage and bone mineral density (BMD) in AS patients with active disease.

Methods

201 consecutive AS outpatients of the Groningen Leeuwarden AS (GLAS) cohort were included. Serum markers of bone resorption (C-telopeptides of type-I collagen, sCTX) and bone formation (procollagen type-I N-terminal peptide, PINP; bone-specific alkaline phosphatase, BALP) were measured. Z-scores were used to correct for the normal influence that age and gender have on bone turnover. Radiographs were scored by two independent readers according to modified Stoke AS Spinal Score (mSASSS). The presence of complete bridging (ankylosis of at least two vertebrae) was considered as measure of more advanced radiographic damage. Low BMD was defined as lumbar spine and/or hip BMD Z-score ≤ −1.

Results

Of the 151 patients with complete data, 52 (34%) had ≥1 complete bridge, 49 (33%) had ≥1 syndesmophyte (non-bridging), and 50 (33%) had no syndesmophytes. 66 (44%) had low BMD. Patients with bridging had significantly higher sCTX and PINP Z-scores than patients without bridging (0.43 vs. −0.55 and 0.55 vs. 0.04, respectively). Patients with low BMD had significantly higher sCTX Z-score than patients with normal BMD (−0.08 vs. −0.61). After correcting for gender, symptom duration, and CRP, sCTX Z-score remained significantly related to the presence of low BMD alone (OR: 1.60), bridging alone (OR: 1.82), and bridging in combination with low BMD (OR: 2.26).

Conclusions

This cross-sectional study in AS patients with active and relatively long-standing disease demonstrated that higher serum levels of sCTX, and to a lesser extent PINP, are associated with the presence of complete bridging. sCTX was also associated with low BMD. Longitudinal studies are needed to confirm that serum levels of sCTX can serve as objective marker for bone-related outcome in AS.

[Appropriateness of diagnostic tests in cardiovascular prevention: what can we skip?]

In recent years, a huge increase in the use of cardiac procedures, both invasive and non-invasive, was observed. Diagnostic tests, mainly non-invasive tests, are often prescribed inappropriately, in most cases replacing the clinical evaluation. The rate of inappropriate tests in cardiology is largely variable, depending on regional issues and different medical approach. When the test entails radiation exposure, the biological risk for both the patient and the environment must be taken into account. For this reason, the test that results in less biological risk should always be preferred as a first step.Moreover, it has not been clearly demonstrated that some diagnostic tests help to improve the outcome, that is to prevent cardiovascular events. As many as one sixth of the patients who undergo stress imaging are not taking proper medication, and very frequently no change in therapy is made after the test, regardless of the outcome. Since the appropriateness of diagnostic evaluation requests is mandatory, we focused on the diagnostic tests usually performed in primary and secondary prevention that carry no contribution to the clinical management of patients. This review addresses the need to optimize available resources, reduce costs and avoid unnecessary cardiovascular assessments, thereby enhancing the more efficient care delivery models.

[Is medical imaging iatrogenic?]

Imaging is an indispensable element of modern medicine but is not without risk. Low-dose irradiation due to spinal, abdominal, pelvic or cardiac radiography, and the increasing use of CT carries an additional, albeit moderate risk of cancer. Iodinated and gadolinium-containing contrast media, besides their direct toxicity, can trigger hypersensitivity and allergic-like reactions. Spinal and articular diagnostic injections can also lead to complications. This article reviews the direct iatrogenicity of diagnostic imaging and current efforts to limit it through the use of new radiological systems, lower-dose CT non ionic contrast media, and alternative imaging techniques. The authors also examine the less known but more frequent problem of indirect iatrogenesis, which is highly dependent on the quality of the imaging personnel and technique. Finally, we propose some legislative solutions to this problem.

Approaches to aspects of optimisation of protection in diagnostic radiology in six continents

There has been an expansion in the use of x-ray imaging during the last 20 years. Effective arrangements for justification of exposures as well as for optimisation of protection are crucial. The amount of effort put into the latter, the way in which it is organised and the groups carrying this out vary across the globe. A simple survey of organisational arrangements relating to performance testing of x-ray equipment, management of patient dose and other aspects of implementing optimisation has been undertaken. A total of 137 completed survey forms were received from medical physicists in 48 countries. Results for individual countries from which more responses were received, or for groups of neighbouring ones, are compared to portray variations. Some performance testing of x-ray equipment was mandated in most countries (more than 90%), with the tests being performed primarily by hospital or private medical physicists, although other groups are involved. Testing of equipment prior to clinical use was generally high for most regions, but the frequency was lower in Latin America. There was considerable variation in the frequency and regularity of subsequent testing. The prevalence of patient dose surveys was high in Europe, but lower in other continents. Organisational arrangements for testing performance of x-ray equipment, patient dose surveys and implementing optimisation of protection in medical exposures across the globe can be divided into five main groups. Hospital medical physicists take the lead in western Europe and Australia with the involvement of radiographers. Private medical physicists test equipment in Brazil, the USA and New Zealand, and have some responsibility for optimisation in Brazil. University personnel have significant involvement, together with medical physicists in eastern Europe, but the extent of the coverage is uncertain. Government personnel and service engineers carry out equipment testing in many countries of Africa and Asia, while radiographers have a significant role in Thailand and other countries where the number of medical physicists is limited. In order for dose surveys to have an impact, action must be taken upon the findings, but there must be an effective link between surveyors and radiology facility staff to ensure that this is done.

Estimation of the collective dose in the Portuguese population due to medical procedures in 2010

In a wide range of medical fields, technological advancements have led to an increase in the average collective dose in national populations worldwide. Periodic estimations of the average collective population dose due to medical exposure is, therefore of utmost importance, and is now mandatory in countries within the European Union (article 12 of EURATOM directive 97/43). Presented in this work is a report on the estimation of the collective dose in the Portuguese population due to nuclear medicine diagnostic procedures and the Top 20 diagnostic radiology examinations, which represent the 20 exams that contribute the most to the total collective dose in diagnostic radiology and interventional procedures in Europe. This work involved the collaboration of a multidisciplinary taskforce comprising representatives of all major Portuguese stakeholders (universities, research institutions, public and private healthcare providers, administrative services of the National Healthcare System, scientific and professional associations and private service providers). This allowed us to gather a comprehensive amount of data necessary for a robust estimation of the collective effective dose to the Portuguese population. The methodology used for data collection and dose estimation was based on European Commission recommendations, as this work was performed in the framework of the European wide Dose Datamed II project. This is the first study estimating the collective dose for the population in Portugal, considering such a wide national coverage and range of procedures and consisting of important baseline reference data. The taskforce intends to continue developing periodic collective dose estimations in the future. The estimated annual average effective dose for the Portuguese population was of 0.080±0.017 mSv caput(-1) for nuclear medicine exams and of 0.96±0.68 mSv caput(-1) for the Top 20 diagnostic radiology exams.

A prospective study of medical diagnostic radiography and risk of thyroid cancer

Although diagnostic x-ray procedures provide important medical benefits, cancer risks associated with their exposure are also possible, but not well characterized. The US Radiologic Technologists Study (1983-2006) is a nationwide, prospective cohort study with extensive questionnaire data on history of personal diagnostic imaging procedures collected prior to cancer diagnosis. We used Cox proportional hazard regressions to estimate thyroid cancer risks related to the number and type of selected procedures. We assessed potential modifying effects of age and calendar year of the first x-ray procedure in each category of procedures. Incident thyroid cancers (n = 251) were diagnosed among 75,494 technologists (1.3 million person-years; mean follow-up = 17 years). Overall, there was no clear evidence of thyroid cancer risk associated with diagnostic x-rays except for dental x-rays. We observed a 13% increase in thyroid cancer risk for every 10 reported dental radiographs (hazard ratio = 1.13, 95% confidence interval: 1.01, 1.26), which was driven by dental x-rays first received before 1970, but we found no evidence that the relationship between dental x-rays and thyroid cancer was associated with childhood or adolescent exposures as would have been anticipated. The lack of association of thyroid cancer with x-ray procedures that expose the thyroid to higher radiation doses than do dental x-rays underscores the need to conduct a detailed radiation exposure assessment to enable quantitative evaluation of risk.

Appropriate and safe use of diagnostic imaging

Risks of diagnostic imaging include cancer from radiation exposure and nephrogenic systemic fibrosis. The increase in volume of imaging between 1980 and 2006 has led to a sixfold increase in annual per capita radiation exposure. It is predicted that 2 percent of future cancers will be caused by radiation from computed tomography (CT) exposure. Gadolinium contrast media should be avoided in patients with stage 4 or 5 chronic kidney disease because of the risk of nephrogenic systemic fibrosis. Appropriate use of imaging based on guidelines for specific clinical conditions can reduce these risks. Although noncontrast CT of the head is needed to rule out bleeding in patients with suspected stroke within the first three hours of symptom onset, diffusion-weighted imaging with magnetic resonance of the head and neck is superior to CT within three to 24 hours of symptom onset. Headache merits neuroimaging in special circumstances only. Sestamibi radioisotope has less radiation than thallium for myocardial perfusion imaging. Use of intravenous contrast media with abdominopelvic CT significantly increases the diagnostic accuracy for appendicitis. Cholescintigraphy has better discrimination to diagnose acute cholecystitis than CT in patients with equivocal ultrasonography results. Limited three-view intravenous urography is recommended in pregnancy to evaluate urolithiasis if initial ultrasonography findings are negative or equivocal. Given that many asymptomatic adults have abnormal findings on lumbar spine magnetic resonance imaging, this modality generally should not be performed for nonspecific chronic low back pain in the absence of red flags. Whole body scanning is not supported by current evidence.

Effective dose and breast dose reduction in paediatric scoliosis X-ray radiography by an optimal positioning

The purpose of this article is to recommend positioning to reduce the effective and breast-absorbed-doses in paediatric scoliosis radiography. Effective and breast-absorbed-doses were evaluated using Monte Carlo simulations. Head directed towards the anode (HTA) positioning rather than head directed towards the cathode (HTC) reduces the effective dose to 98 % in anterior posterior (AP), 98 % in left lateral (L LAT) and 96 % in right lateral (R LAT) projections. HTC in posterior anterior (PA) projection contributes a smaller effective dose than HTA by <1 %, but causes a breast-absorbed-dose excess (HTA/HTC breast dose ratios were 85 and 87 % for 10- and 15-y- olds). With the preferential HTA positioning, R LAT projection reduced effective dose to 85 and 84 % compared with L LAT, for 10 and 15 y olds. AP-HTA projection caused 183 and 181 % larger effective doses than PA-HTA and breast-absorbed-dose excesses of 550 and 879 %, for 10 and 15 y olds. When possible, use R LAT and PA projections to reduce effective dose; Of secondary importance, whenever possible, use HTA, with the exception that for 15 y olds, PA-HTC reduces the effective dose more than HTA (1 %) but causes a breast-absorbed-dose excess.

Medico-legal and ethical aspects of nasal fractures secondary to assault: do we owe a duty of care to advise patients to have a facial x-ray?

Guidelines advise that x-rays do not contribute to the clinical management of simple nasal fractures. However, in cases of simple nasal fracture secondary to assault, a facial x-ray may provide additional legal evidence should the victim wish to press charges, though there is no published guidance. We examine the ethical and medico-legal issues surrounding this controversial area.

Informed consent in human research: what to say and how to say it

To ensure that the possibility of harm to human research subjects is minimized, clinical trials and other research protocols are subject to oversight by Institutional Review Boards (IRBs). IRBs require that subjects be fully informed about the real or potential risks of participation in a research study. The use of radiological examinations in research protocols subjects the participants to exposure to ionizing radiation, which in theory carries a risk of stochastic effects such as radiation-induced cancer, and in practice may lead to deterministic effects such as skin injury. Because IRB members and clinical study coordinators may have little knowledge of radiation effects or how best to communicate the risk to the research subjects, they will consult with institutional Radiation Safety Committees and radiation protection professionals regarding how to integrate radiation risk information into the informed consent process. Elements of radiation informed consent include: (1) comparison of the radiation dose to some benchmark that enables the study subjects to make a value judgment regarding the acceptability of the risk; (2) a quantitative expression of the absolute risk of stochastic effects; (3) an expression of uncertainty in the risk; and (4) understandability. Standardized risk statement templates may be created for specific radiological examinations. These standardized risk statements may be deployed as paper forms or electronically in the form of internet-based applications. The technical nature of creating useful radiation risk statements represents an opportunity for radiation protection professionals to participate productively in the clinical research process.

Evaluation of the level of knowledge of Egyptian women of breast cancer and its risk factors. A cross sectional study

Breast cancer is considered the leading cause of cancer death among females in economically developing countries. Prevalence of breast carcinoma is high in Egypt and the cases of breast cancer constitute 29% of cancer cases treated at the national cancer institute. This study aimed at exploring the level of knowledge of Egyptian females of breast cancer and its risk factors. An interview questionnaire with 22 questions about breast cancer was developed. This questionnaire was previously published as a part of the German multicentre DACH study). A total of 600 female subjects that attended primary health care centres were enrolled in our study. The majority were located in Cairo with the mean age of 40.5 +/- 11.0. Most of our studied sample (94%) has heard about breast cancer as a disease. TV and radio were the main sources of knowledge about the disease (60%). The level of knowledge about breast cancer was limited in 80% of the subjects. Younger age subjects had a higher level of knowledge about breast cancer compared to older subjects with no significant difference statistically. The grade of knowledge about breast cancer was higher among highly educated subjects compared to less educated subjects with significant difference statistically. The highest known risk factors of breast cancer were exposure to X ray (79.5%), hormonal therapy (75.7%) and previous breast cancer disease (70.8%). This study clearly illustrates the need for a health education program directed to Egyptian females to improve the knowledge of breast cancer.

Effective dose and risks from medical X-ray procedures

The radiation risks from a range of medical x-ray examinations (radiography, fluoroscopy, and computed tomography) were assessed as a function of the age and sex of the patient using risk models described in Publication 103 (ICRP, 2007) and UNSCEAR (2006, Annex A). Such estimates of risk based on typical organ doses were compared with those derived from effective doses using the International Commission on Radiological Protection's nominal risk coefficients. Methodologically similar but not identical dose and risk calculations were performed independently at the Institute of Radiation Hygiene (Russia) and the Health Protection Agency (UK), and led to similar conclusions. The radiogenic risk of stochastic health effects following various x-ray procedures varied significantly with the patient's age and sex, but to differing degrees depending on which body organs were irradiated. In general, the risks of radiation-induced stochastic health effects in children are estimated to be higher (by a factor of ≤ 4) than in adults, and risks in senior patients are lower by a factor of ≥ 10 relative to younger people. If risks are assessed on the basis of effective dose, they are underestimated for children of both sexes by a factor of ≤ 4. This approach overestimates risks by a factor of ≤ 3 for adults and about an order of magnitude for senior patients. The significant sex and age dependence of radiogenic risk for different cancer types is an important consideration for radiologists when planning x-ray examinations. Whereas effective dose was not intended to provide a measure of risk associated with such examinations, it may be sufficient to make simple adjustments to the nominal risk per unit effective dose to account for age and sex differences.