[Frequency and doses of diagnostic and interventional X­ray applications : Trends between 2007 and 2014]. / Häufigkeit und Dosis diagnostischer und interventioneller Röntgenanwendungen : Trends zwischen 2007 und 2014.

BACKGROUND: In Germany, approximately 95% of man-made radiation exposure of the population results from diagnostic and interventional X­ray procedures. Thus, radiation protection of patients in this field of application is of great importance. OBJECTIVE: Quantification and evaluation of current data on the frequency and doses of X­ray procedures as well as temporal trends for the years 2007-2014. MATERIAL AND METHODS: For outpatients the frequency of X­ray procedures was estimated using reimbursement data from health insurances and for inpatients by means of hospital statistics. For the years under review, representative values for the effective dose per X­ray application were determined mainly from data reported by X­ray departments to the competent authorities. RESULTS: In 2014 approximately 140 million X­ray procedures were performed in Germany with some 40% from dental examinations. On average 1.7 procedures per inhabitant and year were almost constantly carried out between 2007 and 2014. Besides dental diagnostics, X­ray examinations of the skeleton and thorax were performed most frequently. The number of computed tomography (CT) examinations increased by approximately 40%. The increase in magnetic resonance imaging (MRI) was even more pronounced with approximately 55% but overall CT examinations were still performed more often than MRI. The doses per X­ray procedure were only slightly reduced, despite the various dose reduction approaches established in recent years; therefore, the mean effective dose per inhabitant increased from approximately 1.4 mSv in 2007 to 1.6 mSv in 2014, mainly due to the increasing frequency of CT examinations. CONCLUSION: The principles of justification and optimization of radiological procedures are to be consistently applied in each individual instance, especially in the case of CT examinations.

Prospective Evaluation of the radiologist's hand dose in CT-guided interventions.

PURPOSE: Assessment of radiologist's hand dose in CT-guided interventions and determination of influencing factors. MATERIALS AND METHODS: The following CT-guided interventions were included: Core biopsy, drainage, periradicular therapy, and celiac plexus neurolysis. The hand dose was measured with an immediately readable dosimeter, the EDD-30 (Unfors, Sweden). The default parameters for CT fluoroscopy were 120 kV, 90 mA and a 4 mm slice thickness. All interventions were performed on a 16-slice CT unit (Aquilion 16 Toshiba, Japan). The tumor size, degree of difficulty (1 - 3), level of experience and device parameters (mAs, dose-length product, scan time) were documented. RESULTS: 138 CT-guided interventions (biopsy n = 99, drainage n = 23, pain therapy n = 16) at different locations (lung n = 41, retroperitoneum n = 53, liver n = 25, spine n = 19) were included. The lesion size was 4 - 240 mm (median: 23 mm). The fluoroscopy time per intervention was 4.6 - 140.2 s (median: 24.2 s). The measured hand dose ranged from 0.001 - 3.02 mSv (median: 0.22 mSv). The median hand dose for lung puncture (n = 41) was slightly higher (median: 0.32 mSv, p = 0.01) compared to that for the liver, retroperitoneum and other. Besides physical influencing factors, the degree of difficulty (p = 0.001) and summed puncture depth (p = 0.004) correlated significantly with the hand dose. CONCLUSION: The median hand dose for different CT-guided interventions was 0.22 mSv. Therefore, the annual hand dose limit would normally only be reached with about 2000 interventions.

[Radiation hygiene in medical X-ray imaging. Part 3: radiation exposure of patients and risk assessment]. / Strahlenhygiene in der medizinischen Röntgenbildgebung : Teil 3: Strahlenexposition des Patienten und Risikobewertung.

The frequency of X-ray examinations in Germany and the resulting radiation exposure is amongst the highest in comparison with other European countries. To reduce medical radiation exposure and to safeguard radiation protection regulations, the X-ray ordinance stipulates a justification of each individual X-ray application. The justification principle means that the X-ray application should produce sufficient health benefit to offset the radiation risk. Such a benefit-risk assessment needs an adequate estimation of radiation risk. The aim of this paper is to explain the principles of benefit-risk assessment for different situations (e.g. healthcare and screening). The basics and concepts of radiation effects and radiation epidemiology as well as examples of risk estimation and benefit-risk assessments are given.

Incidence of leukaemia and other malignant diseases following injections of the short-lived alpha-emitter 224Ra into man.

We performed an epidemiological study on 1,471 ankylosing spondylitis patients treated with repeated intravenous injections of the short lived alpha-emitter (224)Ra (excluding radiation therapy with X-rays) between 1948 and 1975. These patients have been followed together with a control group of 1,324 ankylosing spondylitis patients treated neither with radioactive drugs nor with X-rays. The mean follow-up time was 26.3 years in the exposed and 24.6 years in the control group. To date, causes of death have been ascertained for 1,006 exposed patients and 1,072 controls. Special emphasis was placed on the reporting of malignant diseases. Expected numbers of cases were computed for the age, sex and calendar year distribution of both groups using cancer registry incidence rates. In the exposed group 18 cases of kidney cancer (vs. 9.1 cases expected, P < 0.01) and 4 malignant thyroid tumours (vs. 1.2 cases expected, P = 0.03) were observed. In the control group the observed cases for these tumours were not significantly elevated. The most striking observation, however, were the 21 cases of leukaemia in the exposed group (vs. 6.8 cases expected, P < 0.001) compared to 12 cases of leukaemia in the control group (vs. 7.5 cases expected). Further sub-classification of the leukaemias demonstrated a high increase of myeloid leukaemia in the exposed group (12 cases observed vs. 2.9 cases expected, P < 0.001), and out of these, especially a high excess of acute myeloid leukaemias (7 cases observed vs. 1.8 expected, P = 0.003). In the controls the observed cases are within the expected range (4 myeloid leukaemias vs. 3.1 cases). This increase in total leukaemias as well as particularly in myeloid leukaemias is significant in direct comparison between the exposed and control groups too (P < 0.05). The enhanced leukaemia incidence in the exposed group is in line with the observation of increased leukaemia incidence in mice injected with (224)Ra.

[Nuclear-medical irradiation during pregnancy. Risk assessment for the offspring]. / Nuklearmedizinische Strahlenexpositionen während der Schwangerschaft. Risikoabschätzungen für die Leibesfrucht.

UNLABELLED: AIM To estimate and evaluate the risks for the offspring due to the administration of radiopharmaceuticals to women during the first pregnancy weeks after conception (weeks p.c.). METHODS: The in-utero exposition of the embryo due to diagnostic nuclear medicine procedures, for which diagnostic reference levels (DRL) are specified, as well as due to radio iodine therapy (RIT) was determined. To this end, it is assumed that the activity of the diagnostic radiopharmaceuticals administered to the mother corresponds with the DRL and amounts to 600 MBq or 4 GBq 131I for RIT of benign or malignant thyroid disease, respectively. Based on these data, the radiation risk for the offspring was assessed and compared with the spontaneous risks (R0). RESULTS: The dose for the offspring does not exceed 7.8 mSv for the diagnostic procedures considered, resulting in an excess risk for the offspring of less than 0.12% (R0 approximately 25%) to die from cancer during life, of less than 0.07% (R0 approximately 0.2%) to develop cancer up to the age of 15 years, and of less than 0.16% (R0 approximately 2%) for hereditary effects. RIT during the first 8 weeks p.c. results in doses for the offspring of about 100-460 mSv, resulting in an excess risk for malformations of the child of 3.4%-22% (R0 approximately 6%). CONCLUSIONS: The risk of stochastic radiation effects for the offspring due to a diagnostic nuclear medicine procedure of the mother during the first 8 weeks p.c. is--compared with the spontaneous risks--very small; deterministic effects are unlikely. In contrast, deterministic effects for the offspring may occur following RIT. In order to decide on a possibly indicated abortion after RIT, an individual risk assessment is mandatory.

Increased risk of myeloid leukaemia in patients with ankylosing spondylitis following treatment with radium-224.

OBJECTIVE: To investigate long-term health effects in AS patients treated with (224)Ra. METHODS: A prospective epidemiological study has been carried out on 1471 AS patients treated with repeated intravenous injections of (224)Ra between 1948 and 1975. These patients have been followed together with a control group of 1324 AS patients not treated with radioactive drugs and/or X-rays. Numbers of malignancies expected in a normal population were computed from German and Danish cancer registry data. RESULTS: After a mean follow-up time of 26 yrs in the exposed group or 25 yrs in the control group, causes of death have been ascertained for 1006 exposed patients and 1072 controls. In particular, 19 cases of leukaemia were observed in the exposure group (vs 6.8 cases expected, P < 0.001) compared to 12 cases of leukaemia in the control group (vs 7.5 cases expected). Further subclassification of the leukaemia cases demonstrated a high increase of myeloid leukaemia in the exposure group (11 cases observed vs 2.9 cases expected, P < 0.001), especially a high excess of acute myeloid leukaemias (7 cases observed vs 1.8 cases expected, P = 0.003), whereas in the controls the observed cases are within the expected range (4 myeloid leukaemias vs 3.1 cases expected). CONCLUSIONS: The enhanced leukaemia incidence in the exposed group is in line with results from experiments in mice injected with varying amounts of the bone-seeking alpha-emitter (224)Ra. In these studies, in animals exposed to lower doses of (224)Ra, i.e. at doses lower than those found to induce osteosarcomas, an increased risk of leukaemia was observed.

[Introduction of a mammography screening program in Germany. Consideration of benefits and risks]. / Einführung eines Mammographiescreeningprogramms in Deutschland Erwägungen zu Nutzen und Risiko.

For women between 50 and 70 years of age, X-ray mammography presently represents the most effective method for early breast cancer detection. It is commonly accepted that quality assured mammography examinations conducted at regular intervals can reduce mortality from breast cancer. In the year 2002, the German Bundestag agreed to the implementation of a mammography screening program for Germany based on the European guidelines. The effectiveness of a mammography screening program is controversially discussed and two of the most commonly cited hazards are the occurrence of false-positive results and the so-called overdiagnosis. Another issue of criticism is the radiation risk due to the mammography examinations. However, in women aged 50-70 years the radiation risk has no substantial importance. In contrast to the present situation in Germany in which opportunistic screening is widespread, standardized quality assured screening will guarantee that false-positive rates are kept as low as possible and that further assessment diagnostics are effective and minimally invasive.

Lung cancer mortality among nuclear workers of the Mayak facilities in the former Soviet Union. An updated analysis considering smoking as the main confounding factor.

A new analysis of lung cancer mortality in a cohort of male Mayak workers who started their employment in the plutonium and reprocessing plants between 1948 and 1958 has been carried out in terms of a relative risk model. The follow-up has been extended until 1999, moreover a new dosimetry system (DOSES2000) has been established. Particular emphasis has been given to a discrimination of the effects of external gamma-exposure and internal alpha-exposure due to incorporated plutonium. This study has also utilized and incorporated the information from a cohort of Mayak reactor workers, who were exposed only externally to gamma-rays. The influence of smoking as the main confounding factor for lung cancer has been studied. The baseline lung cancer mortality rate was not taken from national statistics but was derived from the cohort itself. The estimated excess relative risk for the plutonium alpha-rays was 0.23/Sv (95%CI: 0.16-0.31). The resulting risk coefficient for external gamma-ray exposure was very low with a statistically insignificant estimate of 0.058/Sv (95%CI: -0.072-0.20). The inferred relative risk for smokers was 16.5 (95%CI: 12.6-20.5).

On the conversion of solid cancer excess relative risk into lifetime attributable risk.

Risk coefficients representing the lifetime radiation-induced cancer mortality (or incidence) attributable to an exposure to ionizing radiation, have been published by major international scientific committees. The calculations involve observations in an exposed population and choices of a standard population (for risk transportation), of suitable numerical models, and of computational techniques. The present lack of a firm convention for these choices makes it difficult to inter-compare risk estimates presented by different scientific bodies. Some issues that relate to a necessary harmonization and standardization of risk estimates are explored here. Computational methods are discussed and, in line with the approach utilized by ICRP, conversion factors from excess relative risk (ERR) to lifetime attributable risk (LAR) are exemplified for exposures at all ages and for occupational exposures. A standard population is specified to illustrate the possibility of a simplified standard for risk transportation computations. It is suggested that a more realistic perception of lifetime risk could be gained by the use of coefficients scaled to the lifetime spontaneous cancer rates in the standard population. The resulting quantity lifetime fractional risk (LFR) is advantageous also because it depends much less on the choice of the reference population than the lifetime attributable risk (LAR).

Childhood leukemia in Belarus before and after the Chernobyl accident: continued follow-up.

Earlier assessments led to the conclusion that due to the added radiation after the Chernobyl accident, childhood leukemia in Belarus was not recognisably increased in the years 1987-1994 compared to the years 1982-1986, i.e. the period before the accident. The present paper gives the data of the continued follow-up (1995-1998) which was conducted by the Institute of Haematology and Blood Transfusion, Minsk. In line with the earlier observations no increase has been identified. The incidence rates have been compared to the data of the newly established Belarussian Childhood Cancer Registry and a tentative explanation is given for apparent differences between the rates from our follow-up and the data reported earlier by the Belarussian Childhood Cancer Registry.

The LNT-controversy and the concept of "controllable dose".

There is no firm scientific information on the potential health effects, such as increased cancer rates, due to low doses of ionizing radiation. In view of this uncertainty ICRP has adopted as a prudent default option the linear no-threshold (LNT) assumption and has used it to derive nominal risk coefficients. Subsequent steps, such as the comparison of putative fatality rates in radiation workers with observed accident rates in other professions, have given the risk estimates a false appearance of scientific fact. This has encouraged meaningless computations of radiation-induced fatalities in large populations and has caused a trend to measure dose limits for the public not against the magnitude of the natural radiation exposure and its geographic variations, but against the numerical risk estimates. In reaction to this development, opposing claims are being made of a threshold in dose for deleterious health effects in humans. In view of the growing polarization, ICRP is now exploring a new concept "controllable dose" that aims to abandon the quantity collective dose, emphasizing, instead, individual dose and, in particular, the control of the maximum individual dose from single sources. Essential features of the new proposal are here examined, and it is concluded that the control of individual dose will still have to be accompanied by the avoidance of unnecessary exposures of large populations, even if their magnitude lies below that acceptable to the individual. If a reasonable cut-off at trivial doses is made, the collective dose can remain useful. Misapplications of collective dose are not the deeper cause of the current controversy; the actual root is the misrepresentation of the LNT-assumption as a scientific fact and the amplification of this confusion by loose terminology. If over-interpretation and distortion are avoided, the current system of radiation protection is workable and essentially sound, and there is no need for a fruitless LNT-controversy. The new concept of controllable dose promises simplifications and improvements, but any major change of principles needs to be carefully considered in a broad discussion that ICRP is presently seeking.

Induction of malignant bone tumors in radium-224 patients: risk estimates based on the improved dosimetry.

Mainly between 1945 and 1955, several thousand German patients with ankylosing spondylitis, tuberculosis, or--in a few cases--other diseases received multiple injections of the short-lived alpha-particle emitter radium-224. In the early 1950s, the follow-up of 899 patients was initiated, and the study has continued since then. It includes most of the high-dose patients and nearly all of those treated as children or juveniles, i.e. under the age of 21. In the study cohort, 56 malignant bone tumors occurred in a temporal wave that peaked 8 years after exposure, whereas less than one case would have been expected during the follow-up. Most of the malignant bone tumors were osteosarcomas and fibrous-histiocytic sarcomas. A new analysis has now been performed, primarily because an improved dosimetry resulted in modified bone surface doses, especially for those treated at younger ages. A significant increase in bone tumor risk with decreasing age at exposure is now demonstrated. The earlier finding of an inverse protraction factor is confirmed. In the new formulation, the dependence on dose rate or duration applies only at higher doses; i.e., the initial slope of the dose dependence is unrelated to dose rate or exposure duration, which is in contrast to earlier analyses but is in agreement with microdosimetric considerations and general radiobiological experience.

Malignancies in patients treated with high doses of radium-224.

Predominantly from 1945 to 1955, a group of patients in Germany was treated with multiple injections of the short-lived alpha-particle emitter (224)Ra. The patients suffered from ankylosing spondylitis, tuberculosis and in a few cases from other diseases. The "Spiess study" (study I) follows up the health of 899 of these patients; it includes most of the patients who were treated with high doses (mean bone surface dose: 30 Gy, mean specific activity: 0.66 MBq/kg), and nearly all of those treated under the age of 21 years. The most striking consequence of the (224)Ra injections was the occurrence of 56 malignant bone tumors. They appeared in a temporal wave that peaked around 8 years after exposure. A new analysis was recently performed, because a reassessment of the dosimetry resulted in changed bone surface doses, especially for the patients treated at younger ages. Averaged over all ages at exposure, the estimated risk coefficient is in general agreement with earlier analyses. However, there is now an increase in bone tumor risk that is significantly greater for younger ages at exposure. The earlier finding of an inverse protraction factor is confirmed. During the most recent years of follow-up, a significant excess of nonskeletal solid malignancies has become manifest. In 1998, a significant increase of breast cancer incidence, of soft tissue malignancies, of thyroid carcinomas, and of liver, kidney and bladder cancer was found. An eightfold increased risk of mammary cancers in those treated at a young age is particularly striking. Equally notable are two cases of breast cancer in male patients. To identify potential confounders, a control group of tuberculosis patients not treated with (224)Ra was established. The comparison confirms that the (224)Ra treatment is responsible for most of the excess of mammary cancer.

Late effects in ankylosing spondylitis patients treated with 224Ra.

This study is comprised of 1577 ankylosing spondylitis patients from 9 German hospitals who have been treated with multiple injections of (224)Ra. The majority of the patients, most of them treated in the years 1948-1975, received one series of 10 weekly intravenous injections of about 1 MBq of (224)Ra each. This dose leads to a mean absorbed dose due to alpha-particle radiation of 0.56 Gy to the marrow-free skeleton of a 70- kg man (mean bone surface dose of about 5 Gy). To provide comparative information on causes of death and on health effects possibly related to the basic disease itself, a control group of 1462 ankylosing spondylitis patients with roughly the same age distribution has been established. By the end of 1998, 649 patients in the exposed group and 762 control patients had died. Among other observations, it is of particular interest that 13 cases of leukemia in the exposed group have been observed. This is a highly significant excess (P < 0.001) compared to a standard population, but only a marginally significant excess in comparison to the seven cases observed in the control group. Subclassification of the leukemias shows a clear preponderance of the myeloid leukemias in the exposed group (8 cases observed compared to 1.7 cases expected, P < 0.001), whereas in the control group the observed cases are within the expected range for myeloid leukemia (3 cases observed compared to 2.2 cases expected, P = 0.3). The (224)Ra cohort of the earlier study (higher-dose group) has provided a risk coefficient that predicts about 8 excess malignant bone tumors for the irradiated cohort in this study. In actuality, 4 cases of malignant tumors in the skeleton have been observed so far. However, excess of breast cancer has not been observed in either the irradiated or the control group, which is in contrast to the findings in the earlier (224)Ra cohort of Study I.