Radiological Risk to Human and Non-Human Biota Due to Radioactivity in Coastal Sand and Marine Sediments, Gulf of Oman

Natural and 137Cs radioactivity in coastal marine sediment samples was measured using gamma spectrometry. Samples were collected at 16 locations from four beaches along the coastal area of Muscat City, Gulf of Oman. Radioactivity in beach sand was used to estimate the radiological risk parameters to humans, whereas the radioactivity in marine sediments was used to assess the radiological risk parameters to non-human biota, using the ERICA Tool. The average radioactivity concentrations (Bqkg-1) of 226Ra, 232Th, 40K, 210Pb and 137Cs in sediments (sand) were as follows: 16.2 (16.3), 34.5(27.8), 54.7 (45.6), 46.8 (44.9) and 0.08 (0.10), respectively. In sand samples, the estimated average indoor (Din) and outdoor (Dout) air absorbed dose rates due to natural radioactivity were 49.26 and 27.4 and the total effective dose (AEDTotal; µSvy-1) ranged from 150.2 to 498.9 (average: 275.2). The measured radioactivity resulted in an excess lifetime cancer risk (ELCR) in the range of 58-203 (average: 111) in and an average gonadal dose (AGD; µGy.y-1) ranged from 97.3 to 329.5 (average: 181.1). Total dose rate per marine organism ranged from 0.035 µGy h-1 (in zooplankton) to 0.564 µGy h-1 (in phytoplankton). The results showed marine sediments as an important source of radiation exposure to biota in the aquatic environment. Regular monitoring of radioactivity levels is vital for radiation risk confinement. The results provide an important radiological risk profile parameter to which future radioactivity levels in marine environments can be compared.

Effective doses and associated age-related risks for common paediatric diagnostic nuclear medicine and PET procedures at a large Australian paediatric hospital

INTRODUCTION

Effective dose alone cannot be used to specify and communicate the radiation risk for an individual as risks are dependent on many factors including age and gender. There are limited published data regarding age-specific effective doses and the associated lifetime risk of developing cancers for paediatrics. In this study, we have estimated the typical effective doses for six commonly performed paediatric nuclear medicine and positron emission tomography (PET) studies at the Royal Children's Hospital, Melbourne, Australia. Effective doses were used to estimate and categorise associated stochastic risks with commonly used risk terminology.

METHODS

Paediatric protocols for common nuclear medicine and PET studies and the World Health Organization (WHO) 50th percentile weight-for-age data for females and males aged up to 18 years were used to estimate typical organ and effective doses using ICRP dosimetric tables for radiopharmaceuticals and lifetime risk of cancer incidence using BEIR VII Phase 2 report data. Results were used to determine standardised levels of risk.

RESULTS

Organ doses, effective doses, corresponding lifetime risk of cancer incidence and level of risk category from six common nuclear medicine and PET studies for paediatric patients were calculated and presented for ease of communication.

CONCLUSION

Typical effective doses from common paediatric nuclear medicine and PET studies and the associated lifetime risk of cancer incidence and level of risk have been established for our institution. This can be used to convey risks to health professionals, patients and carers in ways that are easy to understand and compare with other everyday risks.

Communicating radiation risk: the role of public engagement in reaching ALARA

The ALARA (an acronym for 'as low as reasonably achievable') principle, keeping the likelihood of incurring exposure, the number of people exposed and the magnitude of their individual doses 'as low as reasonably achievable, taking into account economic and societal factors', is at the core of radiation protection. For many decades the principle has been an area of continuous development, with recent work highlighting the importance of engaging not only with the decision-makers in the ALARA process but all stakeholders who may incur an exposure. This paper considers a particular case study in which the dredging of non-hazardous sediment in the United Kingdom near a now decommissioned nuclear power station raised substantial public concern about radiological exposure. This turned what was a straightforward construction activity into a complex public engagement and reassurance task, at a significant cost disproportionate to the level of radiological risk. This paper highlights the key lessons learnt from the case study, including not only the importance of engaging the public as part of the ALARA process but also of considering the societal impact arising from stress and concerns if misinformation is allowed to promulgate. A discussion is included on the need to underpin any engagement with a clear plan, including pre-engagement, implementation and reinforcement of messages. In addition, the role of the radiation protection professional is considered in ensuring that all stakeholders are informed, so that ultimately they can come to their own decision on what is safe.

Radiation awareness in an Italian multispecialist sample assessed with a web-based survey

INTRODUCTION

The awareness of radiation doses and risks, also during interventional cardiology procedures, is essential today in order to apply the risk-benefit assessment and to reinforce the principles of justification and optimisation in clinical practice.

METHODS

A voluntary survey with 10 questions and multiple-choice answers was run on a popular cardiology website (www.cardiolink.it) independently by a scientific publisher, in order to evaluate the contemporary level of radiation awareness in a multi-speciality sample of physicians in Italy.

RESULTS

One thousand eight hundred and sixty-one physicians completed the test. The survey showed good results since both prescribers and practitioners (mostly cardiologists) working in Italy are largely aware of the cancer and non-cancer risks of medical radiation use, regardless of their subspecialty background.

CONCLUSION

Physicians are largely aware of the cancer and non-cancer risks of medical radiation use, regardless of their subspecialty background. However, there is still broad space for improvement; in the future, the awareness of radiation risk is a prerequisite to create a culture of respect for radiation hazard and a commitment to minimise exposure and maximise protection.

Lung cancer screening in Europe: where are we in 2021?

This manuscript reviews the recent evidence obtained in lung cancer screening with low dose spiral CT-scan (LDSCT) and focuses on the issues associated with its implementation in Europe. After a review of the magnitude of the lung cancer toll in lives, disease and Euro's, the recently released data of the major lung cancer screening trials are reviewed and mirrored with the results of the US National Lung Screening Trial (NLST), comparing their strengths and weaknesses and areas of future research. The specific barriers and hurdles to be addressed for widely implementing this population screening in European countries are discussed, with special emphasis on the issues of inclusion of smokers, smoking cessation interventions, radiation injury and capacity planning. The pros and cons of including current smokers will be addressed together with the issue which is the better smoking cessation intervention. A medical physicist's view on radiation exposure and quality control will address concerns about radiation induced cancers. The downstream effects of a LDSCT screening program on the capacity of CT-scans, radiologists, thoracic surgeons and radiation oncologists will follow. An estimated roadmap for the future is sketched with the expected role of all key stakeholders. This roadmap reflects the opinion leader's reflections as expressed in a number of discussions with European health authorities, taking place as part of the recently released European Beating Cancer plan.

A Study of Natural Radioactivity Levels and Radon/Thoron Release Potential of Bedrock and Soil in Southeastern Ireland

Radon (²²²Rn) and thoron (²²⁰Rn) account for almost two-thirds of the annual average radiation dose received by the Irish population. A detailed study of natural radioactivity levels and radon and thoron exhalation rates was carried out in a legislatively designated “high radon” area, as based on existing indoor radon measurements. Indoor radon concentrations, airborne radiometric data and stream sediment geochemistry were collated, and a set of soil samples were taken from the study area. The exhalation rates of radon (E²²²_Rn) and thoron (E²²⁰_Rn) for collected samples were determined in the laboratory. The resultant data were classified based on geological and soil type parameters. Geological boundaries were found to be robust classifiers for radon exhalation rates and radon-related variables, whilst soil type classification better differentiates thoron exhalation rates and correlated variables. Linear models were developed to predict the radon and thoron exhalation rates of the study area. Distribution maps of radon and thoron exhalation rates (range: E²²²_Rn [0.15–1.84] and E²²⁰_Rn [475–3029] Bq m⁻² h⁻¹) and annual effective dose (with a mean value of 0.84 mSv y⁻¹) are presented. For some parts of the study area, the calculated annual effective dose exceeds the recommended level of 1 mSv y⁻¹, illustrating a significant radiation risk. Airborne radiometric data were found to be a powerful and fast tool for the prediction of geogenic radon and thoron risk. This robust method can be used for other areas where airborne radiometric data are available.

EXPOSURE LEVELS OF UKRAINIAN POPULATION IN THE CONTEXT OF AN ACTION PLAN TO REDUCE INDOOR RADON LEVELS

OBJECTIVE

To analyze and evaluate the available information to indoor radon concentration in the context of theimplementation of the radon action plan.

METHODS

OBJECT OF STUDY

indoor radon-222 in dwellings by area and corresponding radiation risks of the population. Measurements were performed using passive track radonometry. The exposure time of the radonometers is atleast 30 days during heating season. Radiation risk calculations were performed according to the dose coefficientsand mathematical models of the ICRP.

RESULTS

It was found that for the whole country, reference level 300 Bq/m3 (radon gas) is exceeded in 16 % ofcases. It was found that geometric mean of radon gas levels was 120 Bq/m3 and varies from 35 to 265 Bq/m3 bydifferent area, namely the difference between radon levels in different territories of the country can be up to 7.5times. Variability of radon levels at the district level is also significant. It was found, radon activity concentrationdiffering by almost 10 times by districts with lognormal distribution and a geometric mean of 75 Bq/m3. The analy-sis of radiation risks of the population has established that estimated annual number of lung cancer deaths due toradon in Ukraine is almost 8,900 cases; and а direct economic loss for the country are estimated at more than $450 million a year.

CONCLUSIONS

Surveys of radon levels demonstrated significant variation in radon concentrations between different regions. For the whole country, reference level (300 Bq/m3) is exceeded on above 16 % of the dwellings, butpercentage of exceeding varies from 0.1 to 43.0 % by different area. Information on indoor radon concentrationsin almost a third of the country is non-available. For an effective implementation of the Action plan, it makes sense to introduce radon risk mapping.

COPD Imaging on a 3rd Generation Dual-Source CT: Acquisition of Paired Inspiratory-Expiratory Chest Scans at an Overall Reduced Radiation Risk

As stated by the Fleischner Society, an additional computed tomography (CT) scan in expiration is beneficial in patients with chronic obstructive pulmonary disease (COPD). It was thus the aim of this study to evaluate the radiation risk of a state-of-the-art paired inspiratory-expiratory chest scan compared to inspiration-only examinations. Radiation doses to 28 organs were determined for 824 COPD patients undergoing routine chest examinations at three different CT systems-a conventional multi-slice CT (MSCT), a 2nd generation (2nd-DSCT), and 3rd generation dual-source CT (3rd-DSCT). Patients examined at the 3rd-DSCT received a paired inspiratory-expiratory scan. Organ doses, effective doses, and lifetime attributable cancer risks (LAR) were calculated. All organ and effective doses were significantly lower for the paired inspiratory-expiratory protocol (effective doses: 4.3 ± 1.5 mSv (MSCT), 3.0 ± 1.2 mSv (2nd-DSCT), and 2.0 ± 0.8 mSv (3rd-DSCT)). Accordingly, LAR was lowest for the paired protocol with an estimate of 0.025 % and 0.013% for female and male patients (50 years) respectively. Image quality was not compromised. Paired inspiratory-expiratory scans can be acquired on 3rd-DSCT systems at substantially lower dose and risk levels when compared to inspiration-only scans at conventional CT systems, offering promising prospects for improved COPD diagnosis.

A comparison of COVID-19 and imaging radiation risk in clinical patient populations

The outbreak of coronavirus SARS-COV2 affected more than 180 countries necessitating fast and accurate diagnostic tools. Reverse transcriptase polymerase chain reaction (RT-PCR) has been identified as a gold standard test with Chest CT and Chest Radiography showing promising results as well. However, radiological solutions have not been used extensively for the diagnosis of COVID-19 disease, partly due to radiation risk. This study aimed to provide quantitative comparison of imaging radiation risk versus COVID risk. The analysis was performed in terms of mortality rate per age group. COVID-19 mortality was extracted from epidemiological data across 299,  004 patients published by ISS-Integrated surveillance of COVID-19 in Italy. For radiological risk, the study considered 659 Chest CT performed in adult patients. Organ doses were estimated using a Monte Carlo method and then used to calculate Risk Index that was converted into an upper bound for related mortality rate following NCI-SEER data. COVID-19 mortality showed a rapid rise for ages >30 years old (min: 0.30%; max: 30.20%), whereas only four deaths were reported in the analysed patient cohort for ages <20 years old. The rates decreased for radiation risk across age groups. The median mortality rate across all ages for Chest-CT and Chest-Radiography were 0.007% (min: 0.005%; max: 0.011%) and 0.0003% (min: 0.0002%; max: 0.0004%), respectively. COVID-19, Chest Radiography, and Chest CT mortality rates showed different magnitudes and trends across age groups. In higher ages, the risk of COVID-19 far outweighs that of radiological exams. Based on risk comparison alone, Chest Radiography and CT for COVID-19 care is justified for patients older than 20 and 30 years old, respectively. Notwithstanding other aspects of diagnosis, the present results capture a component of risk consideration associated with the use of imaging for COVID. Once integrated with other diagnostic factors, they may help inform better management of the pandemic.

A New Era in Zero X-ray Ablation

In this article, the authors focus on the importance of the zero X-ray ablation approach in electrophysiology. Radiation exposure related to conventional transcatheter ablation carries small but non-negligible stochastic and deterministic effects on health. Non-fluoroscopic mapping systems can significantly reduce, or even completely avoid, radiological exposure. The zero X-ray approach determines potential clinical benefits in terms of reduction of ionising radiation exposure, as well as safe technical advantages. The use of this method can result in similar outcomes when compared to the conventional fluoroscopic technique. These results are achieved without altering the duration, or compromising the effectiveness and safety, of the procedure. The zero X-ray ablation approach is a feasible and safe alternative to fluoroscopy, which is often only used in selected cases for troubleshooting. The non-fluoroscopic approach is considered a milestone for cancer prevention in ablation procedures.

Projected Cancer Risks to Residents of New Mexico from Exposure to Trinity Radioactive Fallout

The Trinity nuclear test, conducted in 1945, exposed residents of New Mexico to varying degrees of radioactive fallout. Companion papers in this issue have detailed the results of a dose reconstruction that has estimated tissue-specific radiation absorbed doses to residents of New Mexico from internal and external exposure to radioactive fallout in the first year following the Trinity test when more than 90% of the lifetime dose was received. Estimated radiation doses depended on geographic location, race/ethnicity, and age at the time of the test. Here, these doses were applied to sex- and organ-specific risk coefficients (without applying a dose and dose rate effectiveness factor to extrapolate from a population with high-dose/high-dose rates to those with low-dose/low-dose rates) and combined with baseline cancer rates and published life tables to estimate and project the range of radiation-related excess cancers among 581,489 potentially exposed residents of New Mexico. The total lifetime baseline number of all solid cancers [excluding thyroid and non-melanoma skin cancer (NMSC)] was estimated to be 183,000 from 1945 to 2034. Estimates of ranges of numbers of radiation-related excess cancers and corresponding attributable fractions from 1945 to 2034 incorporate various sources of uncertainty. We estimated 90% uncertainty intervals (UIs) of excess cancer cases to be 210 to 460 for all solid cancers (except thyroid cancer and NMSC), 80 to 530 for thyroid cancer, and up to 10 for leukemia (except chronic lymphocytic leukemia), with corresponding attributable fractions ranging from 0.12% to 0.25%, 3.6% to 20%, and 0.02% to 0.31%, respectively. In the counties of Guadalupe, Lincoln, San Miguel, Socorro, and Torrance, which received the greatest fallout deposition, the 90% UI for the projected fraction of thyroid cancers attributable to radioactive fallout from the Trinity test was estimated to be from 17% to 58%. Attributable fractions for cancer types varied by race/ethnicity, but 90% UIs overlapped for all race/ethnicity groups for each cancer grouping. Thus, most cancers that have occurred or will occur among persons exposed to Trinity fallout are likely to be cancers unrelated to exposures from the Trinity nuclear test. While these ranges are based on the most detailed dose reconstruction to date and rely largely on methods previously established through scientific committee agreement, challenges inherent in the dose estimation, and assumptions relied upon both in the risk projection and incorporation of uncertainty are important limitations in quantifying the range of radiation-related excess cancer risk.

Biologically-based modeling of radiation risk and biomarker prevalence for papillary thyroid cancer in Japanese a-bomb survivors 1958-2005

PURPOSE

Thyroid cancer of papillary histology (PTC) is the dominant type in radio-epidemiological cohorts established after nuclear accidents or warfare. Studies on post-Chernobyl PTC and on thyroid cancer in the life span study (LSS) of Japanese a-bomb survivors consistently revealed high radiation risk after exposure during childhood and adolescence. For post-Chernobyl risk assessment overexpression of the CLIP2 gene was proposed as molecular biomarker to separate radiogenic from sporadic PTC. Based on such binary marker a biologically-based risk model of PTC carcinogenesis has been developed for observational Chernobyl data. The model featured two independent molecular pathways of disease development, of which one was associated with radiation exposure. To gain credibility the concept for a mechanistic risk model must be based on general biological features which transcend findings in a single cohort. The purpose of the present study is therefore to demonstrate portability of the model concept by application to PTC incidence data in the LSS. By exploiting the molecular two-path concept we improve the determination of the probability of radiation causing cancer (POC).

MATERIALS AND METHODS

The current analysis uses thyroid cancer incidence data of the LSS with thyroid cancer diagnoses and papillary histology (n = 292) from the follow-up period between 1958 and 2005. Risk analysis was performed with both descriptive and biologically-based models.

RESULTS

Judged by goodness-of-fit all applied models described the data almost equally well. They yielded similar risk estimates in cohorts post-Chernobyl and LSS. The preferred mechanistic model was selected by biological plausibility. It reflected important features of an imperfect radiation marker which are not easily addressed by descriptive models. Precise model predictions of marker prevalence in strata of epidemiological covariables can be tested by molecular measurements. Application of the radiation-related molecular pathway from our preferred model in retrospective risk assessment decreases the threshold dose for 50% POC from 0.33 (95% confidence interval (CI) 0.18; 0.64) Gy to 0.04 (95% CI 0.01; 0.19) Gy for females and from 0.43 (95% CI 0.17; 1.84) Gy to 0.19 (95% CI 0.05; 1.00) Gy for males. These improvements are still not sufficient to separate radiation-induced from sporadic PTC cases at very low doses <0.015 Gy typical for the Fukushima accident.

CONCLUSIONS

Successful application of our preferred mechanistic model to LSS incidence data confirms and improves the biological two-path concept of radiation-induced PTC. Model predictions suggest further molecular validation studies to consolidate the basis of biologically-based risk estimation.

Radiation Doses and Risks in Breast Screening

This article describes radiation doses and cancer risks of digital breast imaging technologies used for breast cancer detection. These include digital mammography (DM), digital breast tomosynthesis (DBT), and newer technologies such as contrast-enhanced digital or spectral mammography (CEM), whole-breast computed tomography, breast-specific gamma imaging (BSGI), molecular breast imaging (MBI), and positron emission mammography (PEM). This article describes the basis for radiation risk estimates, compares radiation doses and risks, and provides benefit-to-radiation-risk ratios for different breast imaging modalities that use ionizing radiation. Current x-ray-based screening modalities such as DM and DBT have small to negligible risks of causing radiation-induced cancers in women of normal screening age. Possible new screening modalities such as CEM have similar small cancer risks. Potential screening modalities that involve radionuclide injection such as BSGI, MBI, and PEM have significantly higher cancer risks unless efficient detection systems and reduced administered doses are used. Benefit-to-radiation-risk estimates are highly favorable for screening with DM and other modalities having comparable (or higher) cancer detection rates and comparably low radiation doses.

The Importance of Neurological Examination for the Indication of Computed Tomography of the Brain in Pediatric Emergency Room

Objectives:

In this study, records of the children who underwent Computed Tomography of the Brain (CTB) were reviewed to increase the awareness of pediatricians to protect patients from radiation, whether CTB was used with right indications or if it was determinative for diagnosis.

Methods:

In total, in this study, 342 cases applied to our Pediatric Emergency Polyclinic between January 2005-December 2010 were retrospectively evaluated regarding complaints at admission, neurological examination and CTB results. The sensitivity and specificity of the neurological examination in detecting the CTB pathology was determined.

Results:

The results were normal in 319 of the 342 cases with CBT and abnormal in 23, out of which abnormal CTB results were only in three (0.99%) of the 301 patients with normal neurological examination results and in 20 (48.8%) of 41 patients with abnormal neurological examination results. The difference between the two groups was statistically significant (p=0.001). The sensitivity and specificity of the neurological examination in detecting CTB pathology were 87% and 94%, respectively.

Conclusion:

Detailed neurological examination of the patients in the pediatric emergency department has a key role in determining the indications for CTB. Clinical follow-up should guide neuroradiological imaging in children with normal results of the neurological examination.

Assessment of knowledge and perceptions of medical radiation among caregivers and adolescent patients in the paediatric emergency department

INTRODUCTION

This study aimed to assess understanding of the potential risks associated with medical imaging among caregivers and adolescent patients in a paediatric emergency department (PED) in Singapore.

METHODS

A prospective convenience sample survey was performed involving adolescents and caregivers presenting to our PED from December 2015 to May 2016. The questionnaire examined demographic data, knowledge of imaging procedures and radiation risks, and expectations regarding information provided about medical radiation.

RESULTS

A total of 349 questionnaires were returned (caregivers 82.5%, adolescents 17.5%). A mean of 6.2 ± 2.4 (out of 11) questions were correctly answered. Those who had tertiary education fared better than those who did not (36.4% vs. 17.2% scoring above the mean, p = 0.001). Age, gender, history of previous imaging and imaging performed during the visit did not affect the score. Two-thirds of the participants did not associate medical radiation with any negative lifetime risk of cancers or know that different scans entailed differing amounts of radiation. Most were unaware that the radiation dose in medical imaging is adjusted to a child's size. Among patients who underwent imaging, 90.1% received explanations on the need for scans, and 26.5% were informed of the risks involved. Almost all participants wished to be informed of imaging indications and risks. More preferred to learn this from physicians (75.6%) or technicians (51.6%) rather than through educational pamphlets (34.4%) or Internet resources (22.9%).

CONCLUSION

Awareness regarding medical radiation needs to be improved in our patient population. A mismatch exists between caregiver expectations and the actual procedure of disclosure of the risk associated with radiation.

Organ Doses, Effective Dose, and Cancer Risk From Coronary CT Angiography Examinations

OBJECTIVE. The purposes of this study were to determine organ and effective doses and to estimate the risk of exposure-induced cancer death (REID) associated with coronary CT angiography (CCTA) examinations. SUBJECTS AND METHODS. CCTA examinations were performed in three stages: calcium score, monitoring, and cardiac phases for all patients. Effective dose was calculated using two methods. The first was based on the scanner-derived dose-length product, and the second entailed use of an organ and effective dose calculator software application. Organ doses were calculated on the basis of the tissue weighting factors of International Commission on Radiation Protection report 103. REID values were assessed with a cancer risk estimator software application. RESULTS. The study included 185 patients (95 men, 90 women). For women, breast doses were high at 52.04 ± 14.08 mGy. The mean effective dose in the women was greater than that in the men (24.05 vs 16.30 mSv, p < 0.05). The mean REID values in patients undergoing CCTA with a 64-MDCT scanner were 13.4 per 10,000 men (1 in 746) and 19.6 per 10,000 women (1 in 508). The REID values were considerably higher for the younger women. CONCLUSION. The results of this study will help referring physicians justify requesting CCTA examinations by considering their benefits for diagnosis on the one hand and awareness of the risk of radiation-induced cancer on the other. In the case of CCTA scans that are properly justified by clinical indication, patients and physicians should not be concerned about the radiation risks.

High Cancer Risk in US Naval Personnel Serving in Nuclear Powered Ships

The USA Defense Threat Reduction Agency provided data in 2014 on the health status, including cancer, of the 4,843 sailors on the nuclear-powered United States Ship (USS) Ronald Reagan over the 2.55-year period from May 12, 2011 to Dec 31, 2013. Also provided were data on a matched control group of 65,269 US Navy personnel. Examination of the control population relative to the US national data gives a relative risk for all malignancies of RR = 9.2 (95% CI 8.48 < 9.2 < 9.96). The result suggests a significant cancer risk associated with serving on a nuclear-powered ship, one which is not predicted by the science underlying current radiation protection legislation.

Radiation risk of incident colorectal cancer by anatomical site among atomic bomb survivors: 1958-2009

Radiation effects on colorectal cancer rates, adjusted for smoking, alcohol intake and frequency of meat consumption and body mass index (BMI) by anatomical subsite (proximal colon, distal colon and rectum) were examined in a cohort of 105,444 atomic bomb survivors. Poisson regression methods were used to describe radiation-associated excess relative risks (ERR) and excess absolute rates (EAR) for the 1958-2009 period. There were 2,960 first primary colorectal cancers including 894 proximal, 871 distal and 1,046 rectal cancers. Smoking, alcohol intake and BMI were associated with subsite-specific cancer background rates. Significant linear dose-responses were found for total colon (sex-averaged ERR/Gy for 70 years old exposed at age 30 = 0.63, 95% confidence interval [CI]: 0.34; 0.98), proximal [ERR = 0.80, 95% CI: 0.32; 1.44] and distal colon cancers [ERR = 0.50, 95% CI: 0.04; 0.97], but not for rectal cancer [ERR = 0.023, 95% CI: -0.081; 0.13]. The ERRs for proximal and distal colon cancers were not significantly different (p = 0.41). The ERR decreased with attained age for total colon, but not for proximal colon cancer, and with calendar year for distal colon cancer. The ERRs and EARs did not vary by age at exposure, except for decreasing trend in EAR for proximal colon cancer. In conclusion, ionizing radiation is associated with increased risk of proximal and distal colon cancers. The ERR for proximal cancer persists over time, but that for distal colon cancer decreases. There continues to be no indication of radiation effects on rectal cancer incidence in this population.

Knowledge about imaging modalities, risks, and protection in radiology among medical students at the University of Hail

Aim

The aim of this study was to evaluate awareness and knowledge about radiation risks and safety principles among medical students at the College of Medicine, University of Hail, Hail, Saudi Arabia, in their clinical years.

Materials and Methods

In this cross-sectional study, an anonymous electronic questionnaire was sent to 174 randomly selected students in clinical years 4-6. The questionnaire contained 38 questions. The respondents' answers to these questions were used to classify them according to their demographic characteristics and to evaluate their knowledge about common imaging modalities, radiation risks, and safety measures. The data were analyzed using the Statistical Package for the Social Sciences (SPSS) software, version 22.

Results

Seventy-five (51.7%) of 145 respondents were female and 70 (48.3%) were male. Fifty-five respondents (37.9%) were in year 4, 38 (26.2%) were in year 5, and 52 (35.9%) were in year 6. The mean score for knowledge about common imaging modalities was 4.10 ± 2.030 of 10, that for knowledge about the risks of radiation was 3.17 ± 1.954 (range, 0-8) of 13, and that for knowledge about radiation protection measures was low at 0.79 ± 0.922 (range, 0-4) of 8. Overall, there was an improvement in knowledge about the imaging modalities and the risks of radiation as the number of clinical years increased (P = 0.000), but it was still unsatisfactory.

Conclusion

The results of this study indicate that the medical students at the University of Hail have very limited knowledge about radiation risks and safety measures. These findings highlight the need for urgent action to improve students' knowledge of these topics.

Precision Radiotherapy and Radiation Risk Assessment: How Do We Overcome Radiogenomic Diversity?

Precision medicine is a rapidly developing area that aims to deliver targeted therapies based on individual patient characteristics. However, current radiation treatment is not yet personalized; consequently, there is a critical need for specific patient characteristics of both tumor and normal tissues to be fully incorporated into dose prescription. Furthermore, current risk assessment following environmental, occupational, or accidental exposures to radiation is based on population effects, and does not account for individual diversity underpinning radiosensitivity. The lack of personalized approaches in both radiotherapy and radiation risk assessment resulted in the current situation where a population-based model, effective dose, is being used. In this review article, to stimulate scientific discussion for precision medicine in both radiotherapy and radiation risk assessment, we propose a novel radiological concept and metric - the personalized dose and the personalized risk index - that incorporate individual physiological, lifestyle-related and genomic variations and radiosensitivity, outlining the potential clinical application for precision medicine. We also review on recent progress in both genomics and biobanking research, which is promising for providing novel insights into individual radiosensitivity, and for creating a novel conceptual framework of precision radiotherapy and radiation risk assessment.

Communicating Radiation Risk: The Power of Planned, Persuasive Messaging

Every day, health physicists and physicians are expected to communicate effectively with concerned people, but rarely (if ever) are they given training on how to effectively communicate. In an age of social media, this paper presents the relevance of teachings from an ancient Greek philosopher. Aristotle's Rhetoric is still considered one of the most influential works on persuasive messaging. He puts the onus of effective communications on the people with the "true" and "just" information to communicate that information clearly to the audience. By communicating with intention-using the persuasive appeals of ethos, pathos, logos, and storytelling-radiation professionals can speak to their expertise in radiation science, while adapting their instructions, presentations, and communication styles to meet the needs of each type of audience: from scientists to concerned citizens, from doctors to first responders, and beyond.

Association Between Prevalence of Peripheral Artery Disease and Radiation Exposure in the Atomic Bomb Survivors

Background Past reports suggested that total-body irradiation at 0.5 to 1.0 Gy could be responsible for atherosclerosis. Peripheral artery disease ( PAD ) is a manifestation of systematic atherosclerosis. Whether the consequences of a low-to-moderate dose of radiation include increased risk of PAD remains to be determined. The purpose of this study was to examine the association between radiation exposure and prevalence of PAD among Japanese atomic bomb survivors. Methods and Results Radiation exposure from the atomic bombing was assessed in 3476 participants (41.1% men, mean age 74.8 years with SD 6.4 years) with a cross-sectional survey in 2010 to 2014. Left- and right-side ankle-brachial indexes and upstroke time ( UT ) were obtained using oscillometric VP -2000. PAD was defined as an ankle-brachial index of 1.0 or less or a prior history related to revascularization. UT was considered a sensitive marker of early-stage PAD . Association between radiation exposure and PAD or UT was assessed using multivariable regression analyses with adjustment for potential confounding factors. Of 3476 participants, 79 (2.3%) were identified as having prevalent PAD . Multivariate logistic regression analysis indicated that radiation dose was unrelated to PAD prevalence (odds ratio, 0.83; 95% confidence interval [0.57-1.21]). UT appeared to increase with radiation dose, but the increase was not statistically significant (1.09 ms/Gy; 95% confidence interval [-0.17 to 2.36]). Conclusions We found no clear association of radiation dose with PAD , but it remains to be determined whether UT is associated with radiation dose.

Inverted C-arm Orientation During Simulated Hip Arthroscopic Surgery

Background

Fluoroscopic guidance is routinely utilized during hip arthroscopic surgery. Previous studies have shown that the C-arm orientation can significantly affect radiation exposure for both the surgeon and the patient during orthopaedic procedures. However, this has not been previously assessed for hip arthroscopic surgery.

Hypothesis

Using an inverted C-arm during hip arthroscopic surgery will reduce radiation exposure to the patient and surgeon.

Study Design

Descriptive laboratory study.

Methods

A simulation study measured scatter radiation during hip arthroscopic surgery performed in the supine position under fluoroscopic guidance with an anthropomorphic pelvic phantom on a radiolucent operating table. Radiation exposure tested 2 different C-arm orientations: standard and inverted. Testing was performed at 6 locations corresponding to the patient, surgeon's neck, surgeon's waist, surgical technician, anesthesiologist, and radiology technician. Statistical analysis was performed using univariate and multivariate analyses assessing radiation exposure between the C-arm orientations. A risk calculation for carcinogenesis was performed based on reported radiation dosages.

Results

Radiation exposure (in mGy/min) was more than 100-fold higher for the patient compared with the surgeon in both C-arm orientations. The inverted C-arm orientation resulted in a 2.48-fold decrease in patient radiation exposure when compared with the standard orientation (10.8 mGy/min vs 26.8 mGy/min, respectively). There was a small but significant increase in surgeon radiation exposure in the inverted orientation compared with the standard orientation (0.072 vs 0.067 mGy/min, respectively). The patient's carcinogenesis risk was decreased 2.64-fold with the inverted orientation compared with the standard orientation (1.4 × 10^-5 vs 3.7 × 10^-5, respectively).

Conclusion

The inverted C-arm orientation resulted in a 2.48-fold decrease in patient radiation exposure with a 2.64-fold decrease in the carcinogenesis risk compared with the standard orientation. Inadvertently, the inverted orientation provided a 9-cm increase in the surgeon's working area. Our data supported the clinical utilization of the inverted C-arm orientation during hip arthroscopic surgery to minimize patient radiation exposure. Although there was a minimal but significant increase in surgeon radiation exposure with the inverted orientation, we believe that this is negligible when incorporated with standard leaded protective equipment as contrasted with the significant dose reduction for the patient as well as the decreased risk of carcinogenesis and hereditary disorders.

Clinical Relevance

Patients undergoing hip arthroscopic surgery routinely acquire radiation exposure during the use of the C-arm. Measures to minimize radiation via the inverted C-arm orientation will decrease the unnecessary risk to the patient while continuing to allow for optimal treatment.

2018 ACC/HRS/NASCI/SCAI/SCCT Expert Consensus Document on Optimal Use of Ionizing Radiation in Cardiovascular Imaging-Best Practices for Safety and Effectiveness, Part 1: Radiation Physics and Radiation Biology: A Report of the American College of Cardiology Task Force on Expert Consensus Decision Pathways Developed in Collaboration With Mended Hearts

The stimulus to create this document was the recognition that ionizing radiation-guided cardiovascular procedures are being performed with increasing frequency, leading to greater patient radiation exposure and, potentially, to greater exposure for clinical personnel. Although the clinical benefit of these procedures is substantial, there is concern about the implications of medical radiation exposure. The American College of Cardiology leadership concluded that it is important to provide practitioners with an educational resource that assembles and interprets the current radiation knowledge base relevant to cardiovascular procedures. By applying this knowledge base, cardiovascular practitioners will be able to select procedures optimally, and minimize radiation exposure to patients and to clinical personnel. Optimal Use of Ionizing Radiation in Cardiovascular Imaging: Best Practices for Safety and Effectiveness is a comprehensive overview of ionizing radiation use in cardiovascular procedures and is published online. To provide the most value to our members, we divided the print version of this document into 2 focused parts. Part I: Radiation Physics and Radiation Biology addresses the issue of medical radiation exposure, the basics of radiation physics and dosimetry, and the basics of radiation biology and radiation-induced adverse effects. Part II: Radiological Equipment Operation, Dose-Sparing Methodologies, Patient and Medical Personnel Protection covers the basics of operation and radiation delivery for the 3 cardiovascular imaging modalities (x-ray fluoroscopy, x-ray computed tomography, and nuclear scintigraphy) and will be published in the next issue of the Journal.

Probability Distribution of Dose and Dose-Rate Effectiveness Factor for use in Estimating Risks of Solid Cancers From Exposure to Low-Let Radiation

This paper presents an analysis to develop a subjective state-of-knowledge probability distribution of a dose and dose-rate effectiveness factor for use in estimating risks of solid cancers from exposure to low linear energy transfer radiation (photons or electrons) whenever linear dose responses from acute and chronic exposure are assumed. A dose and dose-rate effectiveness factor represents an assumption that the risk of a solid cancer per Gy at low acute doses or low dose rates of low linear energy transfer radiation, RL, differs from the risk per Gy at higher acute doses, RH; RL is estimated as RH divided by a dose and dose-rate effectiveness factor, where RH is estimated from analyses of dose responses in Japanese atomic-bomb survivors. A probability distribution to represent uncertainty in a dose and dose-rate effectiveness factor for solid cancers was developed from analyses of epidemiologic data on risks of incidence or mortality from all solid cancers as a group or all cancers excluding leukemias, including (1) analyses of possible nonlinearities in dose responses in atomic-bomb survivors, which give estimates of a low-dose effectiveness factor, and (2) comparisons of risks in radiation workers or members of the public from chronic exposure to low linear energy transfer radiation at low dose rates with risks in atomic-bomb survivors, which give estimates of a dose-rate effectiveness factor. Probability distributions of uncertain low-dose effectiveness factors and dose-rate effectiveness factors for solid cancer incidence and mortality were combined using assumptions about the relative weight that should be assigned to each estimate to represent its relevance to estimation of a dose and dose-rate effectiveness factor. The probability distribution of a dose and dose-rate effectiveness factor for solid cancers developed in this study has a median (50th percentile) and 90% subjective confidence interval of 1.3 (0.47, 3.6). The harmonic mean is 1.1, which implies that the arithmetic mean of an uncertain estimate of the risk of a solid cancer per Gy at low acute doses or low dose rates of low linear energy transfer radiation is only about 10% less than the mean risk per Gy at higher acute doses. Data were also evaluated to define a low acute dose or low dose rate of low linear energy transfer radiation, i.e., a dose or dose rate below which a dose and dose-rate effectiveness factor should be applied in estimating risks of solid cancers.