[Radiation exposure of patients from diagnostic and interventional X-ray procedures. Facts, assessment and trends]

Clinical consequence of the 4-week X-ray control after ESIN osteosynthesis of forearm fractures in children

PURPOSE

The absence of evidence based general guidelines for radiographic follow-ups of pediatric diaphyseal forearm fractures treated with ESIN results in an arbitrary array of X-ray examinations. In most pediatric traumatology departments, an X-ray check is carried out 4 weeks after ESIN osteosynthesis of forearm shaft fractures to detect incipient consolidation of the fracture. However, the elevated sensitivity to ionizing radiation requires special precautions in the pediatric populations. To prevent the indiscriminate use of this diagnostic tool it is necessary to assess the consequence of routinely taken X-rays at the 4-week follow-up.

METHODS

This retrospective analysis included 219 pediatric patients who underwent ESIN treatment for a diaphyseal forearm fracture between 2010 and 2018 at the same pediatric trauma center. The primary outcome was defined as the prevalence of aberrant radiographic findings (ARF) during the 4-week follow-up with an otherwise normal clinical course and examination. Pathologies in the physical exam and irregularities in the medical history were summarized as non-radiological abnormalities (nRD). Binary logistic regression was calculated to identify risk factors associated with an increased likelihood of an ARF.

RESULTS

Of the 219 pediatric patients included, 123 patients had no nRDs at the 4-week follow-up. Only one patient was found to have an ARF (absolute risk = 0.008). Regression showed that the odds of receiving an ARF increased significantly as other nRDs were detected (p = 0.012, OR 14.554). A positive correlation was found especially for irregularities in the medical history (n = 59, p = 0.003, OR = 8.134).

CONCLUSION

This study provides evidence that standardized radiographic follow-up 4 weeks after surgical treatment has no clinical consequences if the course of the fracture is otherwise uneventful. It should be strictly reserved for pediatric patients with a complicated course.

[Imaging after trauma in clinics and practice for children and adolescents : Part 1 of the results of a nationwide online survey of the Pediatric Traumatology Section of the German Trauma Society]

BACKGROUND

The indication for radiography should strictly follow the ALARA (as low as reasonably achievable) principle in pediatric and adolescent trauma patients. The effect of radiation on the growing sensitive tissue of these patients should not be disregarded.

QUESTION

The Pediatric Traumatology Section (SKT) of the German Trauma Society (DGU) wanted to clarify how the principle is followed in trauma care.

METHODS

An online survey was open for 10 weeks. Target groups were trauma surgeons, pediatric surgeons, general surgeons, and orthopedic surgeons.

RESULTS

From Nov. 15, 2019, to Feb. 29, 2020, 788 physicians participated: branch office 20.56%, MVZ 4.31%, hospital 75.13%; resident 16.62%, senior 38.07%, chief 22.59%. By specialist qualification, the distribution was: 38.34% surgery, 33.16% trauma surgery, 36.66% special trauma surgery, 70.34% orthopedics and trauma surgery, 18.78% pediatric surgery. Frequency of contact with fractures in the above age group was reported as 37% < 10/month, 27% < 20/M, 36% > 20/M. About 52% always request radiographs in 2 planes after acute trauma. X-ray of the opposite side for unclear findings was rejected by 70%. 23% use sonography regularly in fracture diagnosis. In polytrauma children and adolescents, whole-body CT is never used in 18%, rarely in 50%, and standard in 14%.

DISCUSSION

The analysis shows that there is no uniform radiological management of children and adolescents with fractures among the respondents.

CONCLUSION

Comparing the results of the survey with the consensus findings of the SKT recently published in this journal, persuasion is still needed to change the use of radiography in primary diagnosis.

Second follow-up of a German cohort on childhood cancer incidence after exposure to postnatal diagnostic x-ray

Studies on children exposed to ionising radiation by computed tomography (CT) indicate an increased risk of leukemia and central nervous system (CNS) tumors. Evidence of the risks associated with diagnostic x-ray examinations, the most frequent examination in pediatric radiology, in which the radiation dose is up to 750 times lower compared to CT examinations, is less clear. This study presents results of the second follow-up for the risk of childhood cancer in a cohort of children (<15 years) with diagnostic x-ray exposure at a large German hospital during 1976-2003 followed for additional 10 years until 2016. With a latency period of 6 months, 92 998 children contributed 794 549 person-years. The median effective dose was 7 μSv. Hundred incident cancer cases were identified: 35 leukemia, 13 lymphomas, 12 CNS tumors, 15 blastomas, 15 sarcomas and 10 other solid tumors, consisting of six germ cells tumors, three thyroid cancers and one adrenocortical carcinoma. For all cancer cases combined the standardised incidence ratio (SIR) was 1.14 (95% confidence interval (CI) 0.93-1.39), for leukemia 1.15 (95% CI 0.63-1.61), for lymphomas 1.03 (95% CI 0.55-1.76), for CNS tumors 0.65 (95% CI 0.34-1.14), for blastomas 1.77 (95% CI 0.91-2.91), for sarcomas 1.28 (95% CI 0.71-2.11) and for other solid tumors 2.38 (95% CI 1.14-4.38). Dose-response analysis using Poisson regression revealed no significant trend for dose groups. Results did not differ substantially with a latency period of 2 years for all cancer entities and 5 years for solid tumors in sensitivity analyses. Overall, the null results of the first follow-up were confirmed. Although an association between radiation exposure and a risk for certain solid tumors like thyroid cancer is known, the significantly increased SIR in the group of other solid tumors must be critically interpreted in the context of the small number of cases and the very low doses of radiation exposure in this group.

Regional Deprivation and Non-Cancer Related Computed Tomography Use in Pediatric Patients in Germany: Cross-Sectional Analysis of Cohort Data

BACKGROUND

Conflicting findings were observed in recent studies assessing the association between patients' area-level socio-economic status and the received number of computed tomography (CT) examinations in children. The aim was to investigate the association between area-level socio-economic status and variation in CT examination practice for pediatric patients in Germany.

METHODS

Data from Radiology Information Systems for children aged 0 to < 15 years without cancer who had at least one CT examination between 2001 and 2010 were extracted in 20 hospitals across Germany. The small-area German Index of Multiple Deprivation (GIMD) was used to assess regional deprivation. The GIMD scores were classified into least, medium and most deprived areas and linked with the patient's last known postal code. A multinomial logistic regression model was used to assess the association between patients' CT numbers and regional deprivation adjusting for age, sex, and location of residence (urban/rural).

RESULTS

A total of 37,810 pediatric patients received 59,571 CT scans during the study period. 27,287 (72%) children received only one CT, while n = 885 (2.3%) received six or more. Increasing numbers of CT examinations in non-cancer patients were significantly associated with higher regional deprivation, which increased, although CI overlap, for higher CT categories: '2-3 CT' odds ratio (OR) = 1.45, 95%CI: 1.40-1.50; '4-5 CT' OR = 1.48, 95%CI: 1.38-1.59; '6+CT' OR = 1.54, 95%CI: 1.41-1.69. In addition, male sex, higher age categories, and specific body regions were positively associated with increased numbers of CT examinations.

CONCLUSION

We observed a positive association between regional deprivation and CT numbers in non-cancer pediatric patients. Limitations of the ecological approach and the lack of differentiation of CT details have to be acknowledged. More information on CT indications is necessary for a full assessment of this finding. In addition, further work on ways to assess socio-economic status more accurately may be required.

Retrospective assessment of self-reported exposure to medical ionizing radiation: results of a feasibility study conducted in Germany

Background

Exposure to medical ionizing radiation has been increasing over the past decades and constitutes the largest contributor to overall radiation exposure in the general population. While occupational exposures are generally monitored by national radiation protection agencies, individual data on medical radiation exposure for the general public are not regularly collected. The aim of this study was to determine the feasibility of assessing lifetime medical ionizing radiation exposure from diagnostic and therapeutic procedures retrospectively and prospectively within the framework of the German National Cohort study.

Methods

Retrospective assessment of individual medical radiation exposure was done using an interviewer-based questionnaire among 199 participants (87 men and 112 women) aged 20–69 randomly drawn from the general population at two recruitment locations in Germany. X-ray cards were distributed to 97 participants at one recruitment center to prospectively collect medical radiation exposure over a 6-month period. The Wilcoxon–Mann–Whitney test was used to test differences in self-reported median examination frequencies for the variables age, sex, and recruitment center. To evaluate the self-reported information on radiological procedures, agreement was assessed using health insurance data as gold standard for the time period 2005 to 2010 from 8 participants.

Results

Participants reported a median of 7 lifetime X-ray examinations (interquartile range 4–13), and 42% (n = 83) reported having had a CT scan (2, IQR = 1–3). Women reported statistically significant more X-ray examinations than men. Individual frequencies above the 75th percentile (≥15 X-ray examinations) were predominantly observed among women and in individuals >50 years of age. The prospective exposure assessment yielded a 60% return-rate of X-ray cards (n = 58). 16 (28%) of the returned cards reported radiological examinations conducted during the 6-month period but generally lacked more detailed exposure information. X-ray examinations reported for the period for which health insurance data were available provided a moderately valid measure of individual medical radiation exposure.

Conclusions

The assessment of more recent medical examinations seems in the German National Cohort study feasible, whereas lifetime medical radiation exposure appears difficult to assess via self-reports. Health insurance data may be a potentially useful tool for the assessment of individual data on medical radiation exposure both retrospectively and prospectively.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-015-1268-8) contains supplementary material, which is available to authorized users.

Accuracy of the sonographic fat pad sign for primary screening of pediatric elbow fractures: a preliminary study

PURPOSE

The purpose of this study was to evaluate the diagnostic accuracy of the sonographic fat pad sign (FPS) as a predictor for pediatric elbow fractures.

PATIENTS AND METHODS

This is a prospective study of children under 14 years with suspected elbow fractures. All participants underwent at first ultrasonography focused on a FPS followed by standard elbow radiographs. US findings were compared to final fracture diagnosis.

RESULTS

38 out of 79 children had an elbow fracture. A sonographic FPS predicted an elbow fracture with a sensitivity/specificity of 97.3/90.5 %, positive/negative likelihood ratios (LR) were 10.2/0.03 and correct/false classification rates were 93.7/6.3 %. Primary US findings were later reviewed by a blinded physician giving a congruity of 96.2 %. These secondary US findings predicted an elbow fracture with a sensitivity/specificity of 92.1/92.7 %, positive/negative LRs were 12.6/0.09 and correct/false classification rates were 92.4/7.5 %.

CONCLUSION

The sonographic FPS could serve as a useful screening tool in primary evaluation of pediatric elbow injuries. If a fracture is unlikely after clinical and US evaluation, additional radiographs are dispensable, thereby potentially minimizing the radiation burden in childhood and reducing the length of stay in the Emergency Department.

Influence of age, sex and calendar year on lifetime accumulated red bone marrow dose from diagnostic radiation exposure

Our aim is to evaluate the relevance of different factors influencing lifetime accumulated red bone marrow dose, such as calendar year, age and sex. The lifetime dose was estimated for controls interviewed in person (N = 2811, 37.5% women) of the population-based representative Northern Germany Leukemia and Lymphoma Study. Data were assessed in standardized computer-assisted personal interviews. The calculation of doses is based on a comprehensive quantification model including calendar year, sex, kind of examination, and technical development. In multivariate regression models the annual red bone marrow dose was analyzed depending on age, sex and calendar year to consider simultaneously temporal changes in radiologic practice and individual risk factors. While the number of examinations continuously rises over time, the dose shows two peaks around 1950 and after 1980. Men are exposed to higher doses than woman. Until 1970 traditional examinations like conventional and mass screening examinations caused the main dose. They were then replaced by technically advanced examinations mainly computed tomography and cardiac catheter. The distribution of the red bone marrow dose over lifetime depends highly on the technical standards and radiation protection survey. To a lesser extent it is influenced by age and sex of the subjects. Thus epidemiological studies concerning the assessment of radiation exposure should consider the calendar year in which the examination was conducted.

Computed tomographies and cancer risk in children: a literature overview of CT practices, risk estimations and an epidemiologic cohort study proposal

Radiation protection is a topic of great public concern and of many scientific investigations, because ionizing radiation is an established risk factor for leukaemia and many solid tumours. Exposure of the public to ionizing radiation includes exposure to background radiation, as well as medical and occupational exposures. A large fraction of the exposure from diagnostic procedures comes from medical imaging. Computed tomography (CT) is the major single contributor of diagnostic radiation exposure. An increase in the use of CTs has been reported over the last decades in many countries. Children have smaller bodies and lower shielding capacities, factors that affect the individual organ doses due to medical imaging. Several risk models have been applied to estimate the cancer burden caused by ionizing radiation from CT. All models predict higher risks for cancer among children exposed to CT as compared to adults. However, the cancer risk associated with CT has not been assessed directly in epidemiological studies. Here, plans are described to conduct an historical cohort study to investigate the cancer incidence in paediatric patients exposed to CT before the age of 15 in Germany. Patients will be recruited from radiology departments of several hospitals. Their individual exposure will be recorded, and time-dependent cumulative organ doses will be calculated. Follow-up for cancer incidence via the German Childhood Cancer Registry will allow computation of standardized incidence ratios using population-based incidence rates for childhood cancer. Dose-response modelling and analyses for subgroups of children based on the indication for and the result of the CT will be performed.

Radiation protection in pediatric radiology

BACKGROUND

The German Federal Law on Radiation Control contains no special provisions for X-ray studies in children and adolescents, even though exposure to ionizing radiation must be kept especially low in young persons, because their tissues are highly radiosensitive. Children, who have many years left to live, are more likely than adults to develop radiation-induced cancer; also, as future parents, they are at risk for passing on radiation-induced genetic defects to the next generation. Whenever possible, radiological studies on children and adolescents should be of a type that does not involve ionizing radiation, such as ultrasonography or magnetic resonance imaging. Pediatric conventional X-rays and computerized tomography (CT) require special examining techniques and protocols that are adapted to the patient's age and to the indication for the study.

METHODS

We selectively review the literature on pediatric dose reduction and discuss our own investigations on the subject as well.

RESULTS

The essential technical prerequisites for lowering the dose of ionizing radiation in conventional X-ray studies include the proper setting of tube voltage, the use of tube filters, suitable patient positioning and fixation, variable use of a scattered-radiation grid, and a modern storage-plate system. In CT studies, the use of age- and indication-adapted protocols can lower radiation exposure by as much as 95%.

CONCLUSION

There are now many ways to lower the exposure of children and adolescents to ionizing radiation without sacrificing diagnostic reliability. The main factors in lowering exposure are proper attention to clinical indications, the use of special X-ray protocols, the use of alternative imaging studies without ionizing radiation wherever possible, and the expertise of the examiner.

Effective doses in radiology and diagnostic nuclear medicine: a catalog

Medical uses of radiation have grown very rapidly over the past decade, and, as of 2007, medical uses represent the largest source of exposure to the U.S. population. Most physicians have difficulty assessing the magnitude of exposure or potential risk. Effective dose provides an approximate indicator of potential detriment from ionizing radiation and should be used as one parameter in evaluating the appropriateness of examinations involving ionizing radiation. The purpose of this review is to provide a compilation of effective doses for radiologic and nuclear medicine procedures. Standard radiographic examinations have average effective doses that vary by over a factor of 1000 (0.01-10 mSv). Computed tomographic examinations tend to be in a more narrow range but have relatively high average effective doses (approximately 2-20 mSv), and average effective doses for interventional procedures usually range from 5-70 mSv. Average effective dose for most nuclear medicine procedures varies between 0.3 and 20 mSv. These doses can be compared with the average annual effective dose from background radiation of about 3 mSv.

Comparison of the image quality of various fixed and dose modulated protocols for soft tissue neck CT on a GE Lightspeed scanner

PURPOSE

Up-to-date CT scanners provide high quality soft tissue imaging of the neck, but scanning protocols often are not optimized regarding radiation dose. Thus, we tried to find a dose-optimized protocol for soft tissue imaging of the neck.

MATERIAL AND METHODS

70 patients were scanned with a 16-row CT-scanner (Lightspeed, GE) with seven different protocols. We used four fixed tube current settings (225, 200, 175 and 150 mA; corresponding CTDI(vol)=10.6, 9.5, 8.3 and 7.1 mGy) and three z-axis dose modulations with a relatively high, moderate and low dose (calculated CTDI(vol)=10.5, 9.1, 7.7 mGy). Representative slices of seven anatomical regions (from the nasopharynx to the aortic arch) were subjectively judged by two radiologists with respect to image quality (five-point rating scale for noise and sharpness). For each protocol and for each judged anatomical region we determined and compared mean values regarding image quality and local tube current. For each protocol, mean values regarding the volume CT dose index (CTDI(vol)) and the dose-length product (DLP) were statistically compared. Moreover, using the software CT-Expo the respective effective doses and the cumulative organ doses of the thyroid gland were compared.

RESULTS

For a fixed tube current of at least 200 mA (CTDI(vol)=9.5 mGy) and for dose modulations with a moderate or high dose adjustment (calculated CTDI(vol)=9.1 and 10.5 mGy) the image quality was sufficient to excellent. As compared to a fixed tube current of 200 mA, dose modulation with a moderate dose adjustment improved the image quality in regions more vulnerable to noise-related artifacts such as at the level of the shoulder, without a noteworthy difference regarding the DLP. However, the cumulative organ dose of the thyroid gland was 17% lower using dose modulation with a moderate dose adjustment as compared to the fixed tube current of 200 mA. Thus, for a comparison with other scanners, we recommend dose modulation and an averaged CTDI(vol)<9 mGy (or a DLP<250 mGycm).

CONCLUSION

A combination of dose modulation and an averaged CTDI(vol)<9 mGy or a DLP<250 mGycm yields sufficient image quality for soft tissue CT-imaging of the neck.

Radiation protection in diagnostic radiology

INTRODUCTION

The use of ionizing radiation is regulated by legislative bodies to limit both individuals' and the population's exposure to radiation. Germany has implemented the European 97/43/EURATOM directive in national law by updating the existing radiation protection regulations. The German Commission on Radiological Protection regularly publishes statements and recommendations on radiation protection in medicine and diagnostic radiology, such as the introduction of diagnostic reference levels and referral guidelines for radiological and nuclear medicine imaging.

METHODS

Review of selected literature, national and international recommendations and legal texts.

RESULTS

From a radiological protection perspective, clear justification for radiological examinations and techniques aimed at minimizing radiation dose while providing the required diagnostic information, are essential.

DISCUSSION

Referring doctors should be sure to use existing guidelines for medical imaging, and liaise with radiologists and nuclear medicine specialists, with whom they share the responsibility for choosing appropriate imaging modalities.

Medical exposure of the population from diagnostic use of ionizing radiation in luxembourg between 1994 and 2002

A national evaluation on radiation doses from diagnostic procedures (x rays and nuclear medicine) was conducted in Luxembourg for the period 1994-2002 aiming at the estimation of the annual collective dose. The calculations were based on a survey of frequencies of more than 250 types of radiological examinations and included more than 425,000 patients. This evaluation ensured the practical implementation of Article 12 of the European Directive 97/43/EURATOM, which obliges the Member States to determinate the population dose from medical exposure. The results show an increase of the annual effective dose per capita from 1.59 mSv in 1994 to 1.98 mSv in 2002. The impact of computed tomography to dose received from medical use of radiation has dramatically increased in this time period. Luxembourg has one of the highest computed tomography examination rates compared to other health care level I countries. The following measures to minimize medical exposures were proposed in the study: medical physicists should have a more central role to play in patient dosimetry in interventional and diagnostic radiology, especially concerning computed tomography. Also, the implementation of an electronic "X-ray patient card" for all irradiated patients--except dental--and the use of the European referral criteria that give guidance and recommend investigations in various clinical settings can both help to decrease medical radiation exposures.

Heavy metal pad shielding during fluoroscopic interventions

Significant direct and scatter radiation doses to patient and physician may result from routine interventional radiology practice. A lead-free disposable tungsten antimony shielding pad was tested in phantom patients during simulated diagnostic angiography procedures. Although the exact risk of low doses of ionizing radiation is unknown, dramatic dose reductions can be seen with routine use of this simple, sterile pad made from lightweight tungsten antimony material.

[Conventional X-rays and conventional tomography in orthopaedics. Current status]

Although sonography, computed tomography (CT) and magnetic resonance imaging (MRI) are common tools in radiology, conventional X-rays still have a place in orthopaedic diagnostic investigation. The advantages of radiographic imaging are high local resolution concerning bone, economy of time besides relatively low costs and worldwide experience. The conventional X-ray is indispensable for planning surgical procedures and clinical monitoring. For several pathological processes an X-ray is sufficient for diagnosis and therapy (i.e. degeneration, fracture). Early changes of the bone (i.e. osteonecrosis) cannot be detected by X-ray. CT and MRI have closed the diagnostic gap. Indications for conventional tomography are rare.