PET/CT

Summary:

Clinical studies demonstrate a gain in diagnostic accuracy by employing combined PET/CT instead of separate CT and PET imaging. However, whole-body PET/CT examinations result in a comparatively high radiation burden to patients and thus require a proper justification and optimization to avoid repeated exposure or over-exposure of patients. This review article summarizes relevant data concerning radiation exposure of patients resulting from the different components of a combined PET/CT examination and presents different imaging strategies that can help to balance the diagnostic needs and the radiation protection requirements. In addition various dose reduction measures are discussed, some of which can be adopted from CT practice, while others mandate modifications to the existing hardand software of PET/CT systems.

Zusammenfassung:

Klinische Studien belegen, dass durch kombinierte PET/CTUntersuchungen die diagnostische Aussagekraft im Vergleich zu separat durchgeführten PET- und CT-Untersuchungen verbessert werden kann. Allerdings sind PET/ CT-Untersuchungen für den einzelnen Patienten mit einer vergleichsweise hohen Strahlenexposition verbunden, so dass sie einer sorgfältigen Rechtfertigung und Optimierung bedürfen, um Wiederholungsuntersuchungen bzw. unnötig hohe Strahlenexpositionen zu vermeiden. Diese Arbeit gibt einen Überblick über die mit den einzelnen Komponenten einer PET/CT-Untersuchung verbundene Patientenexposition und stellt verschiedene Untersuchungsstrategien mit dem Ziel vor, die diagnostisch erforderliche Bildqualität mit den Anforderungen des Strahlenschutzes in Einklang zu bringen. Darüber hinaus werden verschiedene Dosisreduktionstechniken besprochen, von denen einige direkt aus der konventionellen CT-Praxis übernommen werden können, während andere Modifikationen der derzeitigen Hard- und Software von PET/CT-Systemen erforderlich machen.

Key words:

PET/CT - image fusion - exposure - dosimetry

Schlüsselwörter:

PET/CT - Bildfusion - Exposition - Dosimetrie

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