From dose rate to websites: making measurements accessible, understandable and helpful to the lay public.

The key role of public information in emergency preparedness has more recently been corroborated by the experience of the Great Eastern Japan Earthquake and Tsunami and the subsequent nuclear accident at the Fukushima NPP. Information should meet quality criteria such as openness, accessibility and authenticity. Existing information portals of radiation monitoring networks were frequently used even in Europe, although there was no imminent radiation risk. BfS responded by increasing the polling frequency, publishing current data not validated, refurbishing the website of the BfS 'odlinfo.bfs.de' and adding explanatory text. Public feedback served as a valuable input for improving the site's design. Additional services were implemented for developers of smart phone apps. Websites similar to 'ODLInfo' are available both on European and international levels. NGOs and grass root projects established platforms for uploading and visualising private dose rate measurements in Japan after 11 March 2011. The BfS site is compared with other platforms. Government information has to compete with non-official sources. Options on information strategies are discussed.

Open-source hardware and software and web application for gamma dose rate network operation.

The German Federal Office for Radiation Protection operates a network of about 1800 gamma dose rate stations as a part of the national emergency preparedness plan. Each of the six network centres is capable of operating the network alone. Most of the used hardware and software have been developed in-house under open-source license. Short development cycles and close cooperation between developers and users ensure robustness, transparency and fast maintenance procedures, thus avoiding unnecessary complex solutions. This also reduces the overall costs of the network operation. An easy-to-expand web interface has been developed to make the complete system available to other interested network operators in order to increase cooperation between different countries. The interface is also regularly in use for education during scholarships of trainees supported, e.g. by the 'International Atomic Energy Agency' to operate a local area dose rate monitoring test network.

A new approach to estimate nuclide ratios from measurements with activities close to background.

Measurements of low-level radioactivity often give results of the order of the detection limit. For many applications, interest is not only in estimating activity concentrations of a single radioactive isotope, but focuses on multi-isotope analyses, which often enable inference on the source of the activity detected (e.g. from activity ratios). Obviously, such conclusions become questionable if the measurement merely gives a detection limit for a specific isotope. This is particularly relevant if the presence of an isotope, which shows a low signal only (e.g. due to a short half-life or a small transition probability), is crucial for gaining the information of interest. This paper discusses a new approach which has the potential to solve these problems. Using Bayesian statistics, a method is presented which allows statistical inference on nuclide ratios taking into account both prior knowledge and all information collected from the measurements. It is shown that our method allows quantitative conclusion to be drawn if counts of single isotopes are low or become even negative after background subtraction. Differences to the traditional statistical approach of specifying decision thresholds or detection limits are highlighted. Application of this new approach is illustrated by a number of examples of environmental low-level radioactivity measurements. The capabilities of our approach for spectrum interpretation and source identification are demonstrated with real spectra from air filters, sewage sludge and soil samples.

[Sporadic adult form of nemaline myopathy--a difficult differential diagnosis]. / Sporadische adulte Form der Nemalinmyopathie--eine schwierige Differenzialdiagnose.

We report on a 79 years old female patient with slowly progressive painful weakness of the proximal upper and lower limbs. CK was slightly elevated (242 U 7 l). MRI guided biopsy of the proximal lower limbs revealed the rare findings of nemaline myopathy.

Statistical analysis of uncertainties of gamma-peak identification and area calculation in particulate air-filter environment radionuclide measurements using the results of a Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) organized intercomparison, Part I: assessment of reliability and uncertainties of isotope detection and energy precision using artificial spiked test spectra, Part II: assessment of the true type I error rate and the quality of peak area estimators in relation to type II errors using large numbers of natural spectra.

In this paper, the uncertainties of gamma-ray small peak analysis have been examined. As the intensity of a gamma-ray peak approaches its detection decision limit, derived parameters such as centroid channel energy, peak area, peak area uncertainty, baseline determination, and peak significance are statistically sensitive. The intercomparison exercise organized by the CTBTO provided an excellent opportunity for this to be studied. Near background levels, the false-positive and false-negative peak identification frequencies in artificial test spectra have been compared to statistically predictable limiting values. In addition, naturally occurring radon progeny were used to compare observed variance against nominal uncertainties. The results infer that the applied fit algorithms do not always represent the best estimator. Understanding the statistically predicted peak-finding limit is important for data evaluation and analysis assessment. Furthermore, these results are useful to optimize analytical procedures to achieve the best results.

Digital amorphous silicon flat-panel detector radiography at different exposure doses versus mammography film: possibility of radiation dose reduction in detecting rheumatologic bone defects.

BACKGROUND: Radiographic examinations of the skeleton are the most commonly performed radiologic procedures, even outnumbering examinations of the chest. The imaging systems used in skeletal radiography must meet high standards in terms of contrast and spatial resolution to effectively visualize the high contrast between bone and soft tissue as well as fine bone structures. PURPOSE: To determine the performance of amorphous silicon flat-panel detector radiography compared to mammography film in detecting rheumatologic bone defects at different exposure doses. MATERIAL AND METHODS: The study enrolled 44 patients with known or presumed skeletal changes of the hand associated with inflammatory rheumatic diseases. Following a clinically indicated radiographic examination of the peripheral extremities using mammography film, a survey radiograph of one hand was taken in the posteroanterior (PA) view by digital radiography, at the same exposure dose and at a dose reduced to one quarter of the mammography film doses. Four independent radiologists scored the resultant images using the Sharp/van der Heijde and Ratingen scoring methods. The study received University of Cologne Ethics Committee and German Federal Radiation Protection Agency approval. RESULTS: Compared to mammography film, digital flat-panel detector radiography produced a significantly better image quality at identical uptake doses. A greater number of erosions were detected with the digital flat-panel detector than with mammography film at the same and at reduced doses. CONCLUSION: Although the spatial resolution of the digital flat-panel system used in this study was poorer than mammography film, this was compensated for by its wider dynamic range and improved contrast resolution, even at the reduced dose.

Drug-eluting stents in renal artery stenosis.

Because of higher acute and long-term success rates compared with balloon angioplasty alone, percutaneous stent implantation has become an accepted therapy for the treatment of atherosclerotic renal artery stenosis. Restenosis rates after successful renal stent placement vary from 6 up to 40%, depending on the definition of restenosis, the diameter of the treated vessel segment and comorbidities. The safety and efficacy of drug-eluting stents for the treatment of renal-artery stenosis is poorly defined. The recently published GREAT study is the only prospective study, comparing bare-metal and sirolimus-coated low profile stent systems in renal artery stenosis, showing a relative risk reduction of angiographic binary in-stent restenosis by 50%. This is an opinion paper on indications, current treatment options and restenosis rates following renal artery stenting and the potential use of drug-eluting stents for this indication.

Three years of operational experience from Schauinsland CTBT monitoring station.

Data from three years of operation of a low-level aerosol sampler and analyzer (RASA) at Schauinsland monitoring station are reported. The system is part of the International Monitoring System (IMS) for verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The fully automatic system is capable to measure aerosol borne gamma emitters with high sensitivity and routinely quantifies 7Be and 212Pb. The system had a high level of data availability of 90% within the reporting period. A daily screening process rendered 66 tentative identifications of verification relevant radionuclides since the system entered IMS operation in February 2004. Two of these were real events and associated to a plausible source. The remaining 64 cases can consistently be explained by detector background and statistical phenomena. Inter-comparison with data from a weekly sampler operated at the same station shows instabilities of the calibration during the test phase and a good agreement since certification of the system.

[Ultrasound guided implantation of chest port systems via the lateral subclavian vein]. / Die sonographisch gezielte Implantation von Portkathetersystemen über die laterale Vena subclavia.

PURPOSE: Retrospective analysis of the success and complication rates of chest port implantation via the lateral subclavian vein. MATERIALS AND METHODS: Between January 2003 and June 2004, the lateral subclavian vein in 271 patients (186 women, 85 men, mean age 53.2 years) was punctured guided by ultrasound. This access was used to insert a port system, and the catheter tip was placed at the cavoatrial junction. The port reservoir was implanted in a subcutaneous infraclavicular pocket and fixed to the fascia of the pectoralis muscle. Indications for port implantation were chemotherapy (n = 239), total parenteral nutrition (n = 2) and intravenous medication (n = 30). The patient follow-up was mainly performed either by the oncology division of the department of gynecology or by the department of internal medicine. RESULTS: A chest port catheter system was successfully implanted in all patients. The catheter remained in place for a mean duration of 269.4 days (SD 192.3 days). No complications occurred during implantation. In the post-interventional period, 6 catheter dysfunctions were found (thrombotic 0.09 per 1000 catheter days; mechanic 0.05 per 1000 catheter days). While one local infection occurred in the early post-interventional period, 3 local and 15 systemic infections were independent of the port catheter placement (0.39 per 1000 catheter days). The rate of port catheter ex-plantation due to dysfunction or infection was 0.07 per 1000 catheter days. CONCLUSION: Ultrasound-guided puncture of the lateral subclavian vein is a safe procedure for the insertion of central venous port catheter systems and had a very low complication rate in our study. For further evaluation of our port placement technique, prospective studies compared to placement through the internal jugular vein are necessary.

[Digital X-ray mammography: comparison of the image quality achievable with a wet laser imager, a dry infrared laser imager and a dry laser imager using direct thermography]. / Digitale Röntgenmammographie: Bildqualitativer Vergleich eines Nasslaserdruckers, eines infrarotbasierten Trockenlaserdruckers und eines thermographiebasierten Trockendruckers.

PURPOSE: To compare the image quality of digital X-ray mammographies obtained with wet imagers with that of standard dry imaging technology. MATERIAL AND METHODS: Beginning 03/08/2003, 200 X-ray mammographies with a digital fullfield mammography system (Lorad Selenia, Lorad/Hologic) were prospectively and consecutively documented with a wet laser imager (Scopix LR 5200, Agfa), a dry infrared laser imager (DryView 8610, Kodak) and a dry imager using the principle of direct thermography (Drystar 4500M, Agfa, N = 166). One X-ray exposure was systematically chosen from each examination and was presented in an anonymous and randomized form to three radiologists who evaluated the films using a structured questionnaire. RESULTS: The visualization of normal anatomic structures was considered being good to excellent for all imagers with the mean assessments 1.0 - 2.4 for the Drystar 4500M, 1.0 - 2.1 for the DryView 8610 and 1.1 - 2.0 for the Scopix LR 5200. The mean assessments were 0.1 - 0.6 points lower in dense than in normal parenchyma, thus, the parenchymal density is the predominant factor for image quality. CONCLUSION: In view of the comparable image quality obtained with the different imagers used in the study, individual decisions to purchase a specific imager will be based on economics rather than on diagnostic points of view.

Computed-tomography-guided percutaneous core needle biopsies of suspected malignant lymphomas: impact of biopsy, lesion, and patient parameters on diagnostic yield.

PURPOSE: To investigate the diagnostic yield of core needle biopsy in patients with malignant lymphoma. MATERIAL AND METHODS: Computed-tomography-guided core needle biopsies in patients with malignant lymphoma performed in the period 1996 to 2001 were evaluated retrospectively. A biopsy was considered as "fully diagnostic" if a histological diagnosis, including the histologic subtype in the event of malignant lymphoma, was achieved and the clinical course and CT follow-up of at least 6 months confirmed the biopsy results. A biopsy was regarded as "partly diagnostic" if histological work-up defined malignant lymphoma but not the histological subtype, and if histological diagnosis bore therapeutic relevance. Diagnostic yield was correlated with features such as size of specimen, location and depth of the target lesion, and experience of the investigator. RESULTS: 45 biopsies were performed in 40 patients. With respect to definite histopathological diagnosis, 31 biopsies (68.9%) were diagnostic and 14 (31.1%) non-diagnostic. In 4 cases (8.8%), biopsies yielded partly diagnostic results, since therapy could be scheduled after biopsy without final sub-classification. Statistical analysis of biopsy parameters revealed that sample sizes were significantly larger in the diagnostic group. CONCLUSION: CT-guided biopsy can be considered as an alternative for lymphoma diagnosis and should be the first interventional procedure. The most important parameter for diagnostic success is the size of the specimen.

[MR-coronary angiography: comparison of SSFP and spoiled GRE sequence (bright blood technique) and a TSE sequence (black blood technique) in healthy volunteers]. / MR-Koronarangiographie: Vergleich von SSFP- und gespoilter GRE-Sequenz (Brightblood-Technik) und TSE-Sequenz (Blackblood-Technik) bei gesunden Probanden.

PURPOSE: Comparison of a free breathing steady-state free precession (SSFP), a spoiled gradient-echo (GRE) and a turbo spin-echo sequence (TSE) for imaging of the coronary arteries (MRCA) in healthy volunteers. MATERIALS AND METHODS: Twenty-two healthy volunteers were imaged with a standard clinical scanner (1.5 T, Intera, Philips), with the right coronary system imaged in 11 and the left coronary system in the other 11 volunteers. Images were obtained with a 3D-SSFP (balanced TFE, TR 6.2 ms, TE 3.1 ms, alpha 65 degrees ), a 3D-GRE (TFE, TR 7.2 ms, TE 2.2 ms, alpha 30 degrees ) and a 2D-TSE (Dual-IR, TR 2RR, TE 25 ms) sequence. The in plane resolution was 0.7 x 0.8 mm for both the SSFP and GRE sequence with an effective slice thickness of 1.5 mm. For the TSE sequence, an in-plane resolution of 0.7 x 0.9 mm and a slice thickness of 3.0 mm were used. All investigations were performed using prospective navigator gating and slice-following technique. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) for the blood pool to myocardium and blood pool to epicardial fat were calculated. Image quality and measurement artifacts were assessed for all sequences by 5 independent investigators using a 4- and 5-point grading scale. RESULTS: CNR was significantly higher for the GRE sequence compared with the SSFP sequence and TSE sequence (mean 20.8 +/- 4.8 vs. 14.6 +/- 5.0 and 10.1 +/- 3.7 for blood pool to myocardium; mean 27.5 +/- 6.3 vs. 16.4 +/- 5.4 and 18.1 +/- 5.7 for blood pool to fat). The SNR revealed no significant differences between the SSFP and GRE sequences. The SSFP and the TSE sequences showed significantly more artefacts than the spoiled GRE sequence. Image quality was graded slightly higher for the GRE than for the SSFP sequence for the right coronary system, while there was no substantial difference in the left coronary system (median 2.1 +/- 0.6 and 2.5 +/- 0.6 vs. 2.5 +/- 0.8 and 2.6 +/- 0.7 for the right and left coronary system). In comparison, image quality was lower with the TSE sequence (median 2.9 +/- 0.5 for the right coronary system with p < 0.05 vs. GRE sequence and 3.0 +/- 0.3 for the left coronary system). CONCLUSION: For the scan parameters chosen in this study, the GRE-sequence represents the most robust technique for imaging of the coronary arteries. Currently, the TSE sequence is no alternative.

Radiosurgery for cerebral arteriovenous malformations in hereditary hemorrhagic telangiectasia.

The authors evaluated the efficacy of radiosurgery (RS) for cerebral arteriovenous malformations in hereditary hemorrhagic telangiectasia (HHT AVMs). Two patients with seven HHT AVMs were treated by linear accelerator-RS. Complete obliteration was achieved 18 to 24 months post-treatment without side effects. Because HHT AVMs are small and multiple, RS is superior to microsurgery because it is noninvasive and all AVMs can be treated in one session regardless of their location.

Reducing the radiation dose during excretory urography: flat-panel silicon x-ray detector versus computed radiography.

OBJECTIVE: The purpose of the study was to examine the possibilities for reducing radiation exposure in uroradiology using digital flat-panel silicon X-ray detector radiography. We compared the subjectively determined image quality of abdominal radiographs and urograms obtained on a digital flat-panel detector radiography system with those obtained on a computed radiography system. SUBJECTS AND METHODS. Fifty patients who had a clinical indication for urography underwent unenhanced abdominal imaging that was alternately performed using flat-panel silicon X-ray detector radiography or computed radiography. For patients who required a second radiograph with contrast medium, the examination modality was changed to avoid exposing the patients to excess radiation. The images obtained on flat-panel X-ray detector radiography were obtained at half the radiation dose of the images obtained on computed radiography (800 speed vs 400 speed). The resulting 50 pairs of images were interpreted by four independent observers who rated the detectability of structures of bone and the efferent urinary tract relevant to diagnosis and compared the image quality. RESULTS: At half the radiation dose, digital flat-panel X-ray detector radiography provided equivalent image quality of the liver and spleen, lumbar vertebrae 2 and 5, pelvis, and psoas margin on abdominal radiographs. The image quality obtained with digital flat-panel X-ray detector radiography of the kidneys, the hollow cavities of the upper efferent urinary tract, and the urinary bladder was judged to be statistically better than those obtained with computed radiography. CONCLUSION: With half the exposure dose of computed radiography, the flat-panel X-ray detector produced urograms with an image quality equivalent to or better than computed radiography.

Current indication for endovascular treatment of thoracic aneurysms.

The morbidity and mortality for open treatment of thoracic aortic aneurysms have declined over the years, but it is still a major clinical problem. The reason for the mortality is in almost 50% of the cases cardiac failure. Endoluminal treatment of abdominal aortic aneurysm is widely distributed and with promising results, although not as free from complications as expected 10 years ago. This technique has also been adopted for the thoracic aortic aneurysm as the trauma is much less than in open surgery. In our own personal series no specific workup for coronary heart disease has been made and the mortality of stentgrafting of the thoracic aorta was 2.4%. A survey of the world literature, including elective and acute dissections and aneurysms revealed 642 patients treated with stentgraft with a mortality of 6.2%, although no cardiologic work up had been performed. These numbers compete well with those of open surgery, but a systematic prospective comparison would be needed in order to state the real mortality in both groups.

[Internal carotid artery dissection at the carotid canal after blunt trauma: case report of endovascular repair and literature review]. / Traumatische Dissektion der linken Arteria carotis interna durch stumpfes Trauma: Behandlung mittels endovaskulärer Stent-Versorgung.

Symptomatic dissecting aneurysms of the extracranial internal carotid artery after blunt trauma are not frequent. Medical treatment of these lesions can be ineffective and surgical options present high morbidity. We describe a case successfully treated with endovascular therapy, using a self-expanding stent. The advantages of the endovascular treatment are outlined, the literature on carotid artery injuries by blunt trauma and management strategies are reviewed.

[Quality control of outpatient imaging examinations in North Rhine-Westphalia, Part II]. / Qualitätskontrolle der ambulanten bildgebenden Diagnostik in Nordrhein-Westfalen, Teil II.

PURPOSE: In the state of North Rhine-Westphalia (NRW), Germany, a survey was conducted on radiologic examinations ordered by general practitioners (GPs). Part II of this study aims to determine the quality of the process and outcome. The reference standard is the assessment of both radiologists and physicians without board certification in radiology working at a university hospital and in outpatient facilities. MATERIALS AND METHODS: AllGPs in NRW were asked to cooperate. Participating GPs filled out a questionnaire for each patient. The patients recorded the symptoms prompting the imaging examinations. The radiologists or other physicians performing the examinations were asked to provide the images and written reports and to complete a questionnaire. A file was created for each of the 394 patients with image documentation of at least one examination. Each file, which included medical history, physical findings, imaging documentation and written report, was sequentially forwarded to a board-certified radiologist and to a physician without board certification in radiology working in a university hospital and in an outpatient facility. All physicians were requested to complete a structured questionnaire for each file. RESULTS: The referral diagnoses were rated as medically plausible in 81%, the indications for imaging found correct in 76%, the examination techniques considered appropriate in 69%, the clinical question answered in 63%, the interpretation judged medically correct in 50% and all incidental findings documented in 49%. In retrospect, 32 % of the examinations were judged superfluous. The sequence of multiple examinations performed on a particular patient was rated as appropriate in 51%. The interpretation revealed specialty-related differences. The plausibility of the referral diagnoses had a significant impact on the appropriateness of subsequent diagnostic investigations. Marked deficits showed sonography, performance by non-radiologists, self-referrals by GPs, gastroenterologic radiology and the ICD-10 coding (suspicion of cardiovascular disease). CONCLUSION: In the "best-case" scenario, the process quality proved to have moderate deficiencies and the outcome quality severe deficiencies. In consequence, GPs and radiologists should be more communicative by sharing information and exchanging opinions. GP self-referrals should be restricted. Sonography and examinations performed by physicians without board certification in radiology should undergo stricter quality controls. A more intensive interdisciplinary collaboration is needed to determine the optimum implementation of diagnostic imaging of gastroenterologic and cardiovascular diseases.