Photon-electron coincidence experiments at synchrotron radiation facilities with arbitrary bunch modes.

We report the adaptation of an electron-photon coincidence detection scheme to the multibunch hybrid mode of the synchrotron radiation source BESSY II (Helmholtz-Zentrum Berlin). Single-event-based data acquisition and evaluation, combined with the use of relative detection times between the coincident particles, enable the acquisition of proper coincidence signals from a quasi-continuous excitation pattern. The background signal produced by accidental coincidences in the time difference representation is modeled using the non-coincident electron and photon spectra. We validate the method by reproducing previously published results, which were obtained in the single bunch mode, and illustrate its usability for the multibunch hybrid mode by investigating the photoionization of CO2 into CO2 + B satellite states, followed by subsequent photon emission. The radiative lifetime obtained and the electron binding energy are in good agreement with earlier publications. We expect this method to be a useful tool to extend the versatility of coincident particle detection to arbitrary operation modes of synchrotron radiation facilities and other excitation sources without the need for additional experimental adjustments.

[Generating statements at whole-body imaging with a workflow-optimized software tool--first experiences with multireader analysis]. / Befunderstellung bei der Ganzkörperbildgebung mittels einer workflowoptimierten Befundungssoftware--Erste Erfahrungen einer Multireader-Analyse.

INTRODUCTION: Due to technical innovations in sectional diagram methods, whole-body imaging has increased in importance for clinical radiology, particularly for the diagnosis of systemic tumor disease. Large numbers of images have to be evaluated in increasingly shorter time periods. The aim was to create and evaluate a new software tool to assist and automate the process of diagnosing whole-body datasets. MATERIAL AND METHODS: Thirteen whole-body datasets were evaluated by 3 readers using the conventional system and the new software tool. The times for loading the datasets, examining 5 different regions (head, neck, thorax, abdomen and pelvis/skeletal system) and retrieving a relevant finding for demonstration were acquired. Additionally a Student T-Test was performed. For qualitative analysis the 3 readers used a scale from 0 - 4 (0 = bad, 4 = very good) to assess dataset loading convenience, lesion location assistance, and ease of use. Additionally a kappa value was calculated. RESULTS: The average loading time was 39.7 s (+/- 5.5) with the conventional system and 6.5 s (+/- 1.4) (p < 0.01) with the new software tool. For the different regions (conventional system/new software tool), the time reduction for readers 1, 2, and 3 were as follows: in the head region 35.9 % (p < 0.01)/49.9 % (p < 0.01)/54.3 % (p < 0,01), in the neck region 48.5 % (p < 0.01)/52.6 % (p < 0.01)/59.4 % (p < 0.05), in the thorax region 59.1 % (p < 0.01)/56.2 % (p < 0.05)/62.1 % (p < 0.05), in the abdominal region 61.9 % (p < 0.01)/62.7 % (p < 0.05)/47.9 % (p < 0.01) and in the pelvis region 73.1 % (p < 0.01)/63.7 % (p < 0.05)/55 % (p < 0.01), respectively. 148.2 s (+/- 94.8) compared to 2.5 s (+/- 0.5) were required to retrieve a previously described finding (p < 0.01). With and without the new software tool the same number of metastases was found (p < 0.01, k > 0.9). The qualitative analysis showed a significant advantage with respect to convenience (p < 0.01, k > 0.9). CONCLUSION: Use of the new software can achieve a significant time savings when working with whole-body datasets with a constant quality of findings and a significant advantage with respect to convenience. As a result, the problem of evaluating examinations with thousands of images can be approached systematically.

System solutions for the integration of devices in the OR.

The technical complexity of the surgical arena, as well as of related specialised fields, has increased significantly. A look at the current situation in various surgical disciplines shows that, despite existing high-tech equipment, the operating room (OR) can still not be considered an ergonomic and optimised work environment. Industrial suppliers have integrated new procedures and techniques into surgical disciplines, often without consulting other manufacturers and without establishing or implementing appropriate standards. This paper describes the development of an integrated workstation for the OR and its related technical and clinical aspects, e.g. process analysis, system integration, standardisation, image processing, user interfaces, communication protocols (CANopen, DICOM) and networking. The first introduction of the prototype to our clinical partners has confirmed that the implementation of an optimised system workstation in the OR results in improved processes. The standardised and simplified user guidance leads to improved ergonomy. The selected communication standard between the subsystems of the diverse industrial suppliers gives the user more flexibility in configuring the individual OR system. Intensive collaboration between industry and clinical partners will continue to be vital for the further development of such complex system workstations in medicine.

[Argon plasma coagulation through a flexible endoscope. Evaluation of a new therapeutic method after 1606 uses]. / Argonplasmakoagulation in der flexiblen Endoskopie. Bewertung eines neuen therapeutischen Verfahrens nach 1606 Anwendungen.

BACKGROUND AND OBJECTIVE: Argon plasma coagulation (APC) through a flexible endoscope provides a new technique for thermal devitalization or blood coagulation which is gaining wider attention. This study was undertaken to test clinically the efficacy, safety and ergonomics of the method. PATIENTS AND METHODS: 697 consecutive patients (386 men, 311 women; mean age 67 years [3 months--97 years]) had undergone the procedure in 1606 sitting since 1991. Applications included various forms and causes of bleeding in the upper or lower gastrointestinal tract or bronchial system, malignant and benign tumours, ingrowth of tissues and over-growth in stents, fistulas and, since 1993, angiodysplasias and other dysplasias. RESULTS: The precisely defined therapeutic aim was achieved in nearly all cases during an average of 2.3 sittings per patient, while it failed in 1.5%. Perforations occurred in 5 (0.31%), ending fatally in one. Intestinal wall emphysema was diagnosed in 8 cases (0.5%), all remaining symptom-free. During a mean follow-up period of 23 (1-72) months there were no other serious immediate or late complications or side effects ascribable to the procedure. CONCLUSION: APC is a new efficacious, repeatable, safe and easily learned method for devitalization of tissues and for achieving haemostasis, especially for bleeding from surfaces. Similar applications are being developed in other specialties.

[Esophageal carcinoma: downstaging or stent?]. / Osophaguskarzinom: Downstaging oder Stent?

Multimodal therapeutic concepts including radio-chemotherapy show: High therapeutic benefit for the (10-40%) responses. -No adequate local and/or systemic response in 35-80% of patients. -Relatively high therapeutic risk (20-70% complication rate). -Hardly acceptable quality of life during downstaging. It is concluded that downstaging should be performed only in controlled trials with differentiated staging and control of the local and distant tumor manifestations. Unclear remains the role of surgery. For palliative intentions endoscopy offers new methods (argon plasma coagulation, metal stents) with high effectivity, low complication rate and high comfort for the patient.

[Computer supported documentation of diagnostic results and interpretation of bone scintigraphy]. / Computergestützte Befunddokumentation und -interpretation der Skelettszintigraphie.

A PC software program with a graphical users platform was developed which enables the transfer of bone scintigraphy results to vectorgraphy-based skeleton images, and to implement a fully automatic anatomical localization definition of lesions. Documentation of the results is made possible by a complete, conventional structured medical letter. Additional information such as data on the patient, diagnostic methods and results, sacro-iliacal indexes, recommendations and remarks can be added to the scintigrams. By implementation of a database and PCX-interface, the system is open.

[Highly flexible self-expanding metal mesh stents: a new kind of palliative therapy of malignant dysphagia]. / Hochflexible selbstexpandierende Metallgitterstents: Neuartige Palliativtherapie der malignen Dysphagie.

Metal mesh stents are a new way in the treatment of malignant stenoses. Between 11/91 and 12/93 in 79 patients with malignant stenoses of the esophagus and the esophago-gastric junction 96 highly elastic, knitted, self-expanding nitinol stents (Ultraflex, Boston Scientific) were implanted. Most of the tumors being problematic, preoperated or preradiated, in 78 of 96 implantations endoscopic pretreatment (Laser, Argon Plasma Coagulation (APC), dilatation)--mostly in the same session--was necessary. Follow up time was 21 (2-108) weeks. In this pilot study 3.5 (1-27) controlendoscopies with 2.5 (1-10) endoscopic interventions were performed. 90 of 96 implantations were primarily successful and led to a functional success in 73 of 79 patients. The ability to swallow improved significantly, the score of dysphagia improved from 3.5 to 1.0 (p < 0.001). There were no relevant complications and no stent-related mortality. All stents could be kept patent during the follow up period using the new developed Argon-plasma-coagulation (APC) to treat the ingrowth of granulation tissue or tumor, which was observed during follow up in 72 of 93 implantations. Tumor ingrowth represents the main problem of the method and demands endoscopic posttreatment (APC) in cases with relevant re-obstruction. Impairment of the stent lumen by tumor ingrowth (granulation tissue plays no role) would have been observed in about 60% of the patients without such a treatment.(ABSTRACT TRUNCATED AT 250 WORDS)