What factors influence the R value in data-driven respiratory gating technique? A phantom study.
Naoya Hayashi1, Daisuke Ogasawara, Ryotaro Tokorodani
1Division of Radiology, Department of Medical Technology, Kochi Medical School Hospital, Nankoku, Kochi, Japan.
Nuclear Medicine Communications
|September 9, 2022
Summary
The R value, a metric for respiratory gating effectiveness in PET scanners, is influenced by sphere size, radioactivity, amplitude, and waveform shape. Optimal R values depend on these factors for accurate motion-free imaging.
Area of Science:
- Medical Imaging
- Nuclear Medicine
- Biophysics
Background:
- Respiratory motion significantly degrades PET image quality.
- Data-driven respiratory gating (DDG) algorithms aim to mitigate motion artifacts.
- The R value is a key metric for assessing respiratory waveform effectiveness in DDG.
Purpose of the Study:
- To evaluate the impact of various factors on the R value, a metric for respiratory gating effectiveness.
- To understand how phantom parameters influence the performance of the Advanced Motion Free DDG algorithm in PET.
Main Methods:
- Utilized a programmable respiratory motion phantom (QUASAR) with an 18F-filled sphere.
- Simulated respiratory motion by altering sphere diameter, radioactivity, amplitude, cycle, and waveform shape.
- Analyzed power spectra, R values, and compared DDG waveforms with input data.
Main Results:
- R values increased with sphere diameter, radioactivity concentration, and amplitude.
- The respiratory cycle of 7.5 seconds yielded the highest R value.
- Sinusoidal waveforms resulted in higher R values compared to typical waveforms; R value correlated with power spectrum.
Conclusions:
- Sphere diameter, radioactivity concentration, amplitude, respiratory cycle, and waveform shape are critical factors influencing the R value.
- Accurate peak interval acquisition is compromised by factors like absence of sphere, radioactivity, motion, or rapid respiratory cycles.
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