Comparison of intelligent 4D CT sequence scanning and conventional spiral 4D CT: a first comprehensive phantom study
| Autor: | Frederic Madesta, Thilo Sentker, Susanne Fernolendt, Tobias Gauer, René Werner, Annette Schwarz, Marc Vornehm, Christian Hofmann, Christoph Bert, Juliane Szkitsak |
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| Rok vydání: | 2021 |
| Předmět: |
Artifact (error)
Radiological and Ultrasound Technology Phantoms Imaging Computer science Image quality business.industry Respiration Phase image Imaging phantom 030218 nuclear medicine & medical imaging Intensity (physics) 03 medical and health sciences 0302 clinical medicine 030220 oncology & carcinogenesis Breathing Humans Radiology Nuclear Medicine and imaging Four-Dimensional Computed Tomography Projection (set theory) Nuclear medicine business Tomography Spiral Computed Spiral Retrospective Studies |
| Zdroj: | Physics in Medicine & Biology. 66:015004 |
| ISSN: | 1361-6560 0031-9155 |
| DOI: | 10.1088/1361-6560/abc93a |
| Popis: | 4D CT imaging is a cornerstone of 4D radiotherapy treatment. Clinical 4D CT data are, however, often affected by severe artifacts. The artifacts are mainly caused by breathing irregularity and retrospective correlation of breathing phase information and acquired projection data, which leads to insufficient projection data coverage to allow for proper reconstruction of 4D CT phase images. The recently introduced 4D CT approach i4DCT (intelligent 4D CT sequence scanning) aims to overcome this problem by breathing signal-driven tube control. The present motion phantom study describes the first in-depth evaluation of i4DCT in a real-world scenario. Twenty-eight 4D CT breathing curves of lung and liver tumor patients with pronounced breathing irregularity were selected to program the motion phantom. For every motion pattern, 4D CT imaging was performed with i4DCT and a conventional spiral 4D CT mode. For qualitative evaluation, the reconstructed 4D CT images were presented to clinical experts, who scored image quality. Further quantitative evaluation was based on established image intensity-based artifact metrics to measure (dis)similarity of neighboring image slices. In addition, beam-on and scan times of the scan modes were analyzed. The expert rating revealed a significantly higher image quality for the i4DCT data. The quantitative evaluation further supported the qualitative: While 20% of the slices of the conventional spiral 4D CT images were found to be artifact-affected, the corresponding fraction was only 4% for i4DCT. The beam-on time (surrogate of imaging dose) did not significantly differ between i4DCT and spiral 4D CT. Overall i4DCT scan times (time between first beam-on and last beam-on event, including scan breaks to compensate for breathing irregularity) were, on average, 53% longer compared to spiral CT. Thus, the results underline that i4DCT significantly improves 4D CT image quality compared to standard spiral CT scanning in the case of breathing irregularity during scanning. |
| Databáze: | OpenAIRE |
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