Zusammenfassung
Klinisches/methodisches Problem
Dosisreduktion und adäquate Bildqualität in der digitalen Radiographie – ein Widerspruch?
Radiologische Standardverfahren
Die Verfahren der digitalen Radiographie haben die herkömmlichen Film-Folien-Systeme nahezu vollständig ersetzt.
Methodische Innovationen
Steigende Dosiseffizienz und verbesserte Ortsauflösung sind die wichtigsten Kenngrößen der rasanten Weiterentwicklung digitaler Detektorsysteme.
Leistungsfähigkeit
Bei Nadelkristalldetektoren wurde eine Dosisreduktion bis zu 50% gegenüber Film-Folien-Systemen gefunden. Weiter besteht ein Dosiseinsparungspotenzial von bis zu 50% im Vergleich von Direktradiographie(DR)- mit Computed-radiography(CR)-Systemen bei Thoraxaufnahmen. Trotz der aktuellen Fortschritte bei CR-Systemen ist die Dosiseffizienz von DR-Detektoren (Cäsiumjodidflachbilddetektor) noch deutlich höher.
Bewertung
Die Fortschritte in der Detektortechnologie haben wesentlich zur Dosisreduktion und zu verbesserter Bildqualität einerseits und zu Zeitersparnis und damit höherer Untersuchungsfrequenz andererseits beigetragen.
Empfehlung für die Praxis
Der Einsatz von Dosisindikatoren und eine longitudinale Dosiskontrolle sind wichtig zur Vermeidung eines unbemerkten Dosisanstiegs bei fehlender optischer Kontrolle. Die von der EU vorgegebenen diagnostischen Referenzwerte sollten deutlich unterschritten werden. Regelmäßige Qualitätskontrollen sowie laufende Schulungen des ärztlichen und medizinisch-technischen Personals helfen bei der Sicherstellung der Anwendung des ALARA-Prinzips („as low as reasonably achievable“).
Abstract
Clinical/methodical issue
Dose reduction and adequate image quality in digital radiography – a contradiction?
Standard radiological methods
Digital radiography has already replaced traditional screen-film systems.
Methodical innovations
Substantial improvements in both dose efficiency and spatial resolution demonstrate the rapid developments in digital radiography.
Performance
Needle-detector systems have shown up to a 50% dose reduction compared to traditional screen-film systems. There is also a dose reduction capability of up to 50% comparing direct radiography (DR) systems to computed radiography (CR) systems for chest X-rays. However, despite the most recent achievements of CR technology, the dose efficiency of DR systems (caesium iodide flat-panel detector) is unparalleled.
Achievements
The progress in detector technology has contributed to dose reduction and improved image quality, while saving time and providing a higher examination rate.
Practical recommendations
The use of dose indicators and longitudinal dose control are important to avoid substantial accidental dose increase. The dose applied to patients should fall markedly below the defined diagnostic reference levels within the European Union. Regular quality control, as well as continuous education and training of medical and technical personnel, contribute to ensure that the ALARA (as low as reasonably achievable) principle is consistently followed.
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Danksagung
Wir danken Herrn Dr. Uwe Wolff, Medizinphysiker in der Universitätsklinik für Strahlentherapie AKH/MUW Wien, für die freundliche Unterstützung bei der Erstellung der Thoraxröntgenaufnahmen am Phantom.
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Pötter-Lang, S., Dünkelmeyer, M. & Uffmann, M. Dosisreduktion und adäquate Bildqualität in der digitalen Radiographie: ein Widerspruch?. Radiologe 52, 898–904 (2012). https://doi.org/10.1007/s00117-012-2337-9
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DOI: https://doi.org/10.1007/s00117-012-2337-9
Schlüsselwörter
- Digitale Detektorsysteme
- Dosiseffizienz
- Verbesserte Ortsauflösung
- Qualitätskontrollen
- ALARA („as low as reasonably achievable“)