Nuyts, Johan (2020) Using time-of-flight information for PET, PET/CT and PET/MRI reconstruction. Il nuovo cimento C, 43 (1). pp. 1-3. ISSN 1826-9885
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Abstract
The timing resolution of PET detectors is rapidly improving thanks to new developments in detector design. As a result, the time of flight (TOF) measurement in PET systems is becoming more accurate as well. It has been shown that the TOF measurement supplies information that is not present in non-TOF PET emission data. Because TOF reduces the uncertainty associated with each measured coincidence event, it improves the signal to noise ratio of the reconstructed images. For the same reason, the convergence of iterative reconstruction algorithms is faster and more uniform as well, which also benefits the quality of the reconstructed images. When the TOF resolution is sufficiently high, one can estimate from the TOF-PET data not only the activity distribution, but also the attenuation coefficients. This enables attenuation correction in stand-alone PET scanners and the correction of the available attenuation map in hybrid PET systems. This correction may be valuable, because the CT-based attenuation maps in PET/CT and the MRbased attenuation maps in PET/MR can be degraded by motion, metal artefacts and/or conversion errors. It is observed that for the estimation of the attenuation (or detector sensitivities) from TOF-PET emission data, accurate timing calibration and scatter correction is mandatory. When the calibration and the scatter estimates are accurate, we find that attenuation correction based on the TOF-PET data themselves produces activity images that differ only up to a few percent from the activity images obtained with reference CT-based attenuation correction. With improving TOF resolution, the power of the attenuation estimation algorithms increases, but the accuracy requirements for the timing calibration become more stringent as well.
| Item Type: | Article |
|---|---|
| Subjects: | 500 Scienze naturali e Matematica > 530 Fisica |
| Depositing User: | Marina Spanti |
| Date Deposited: | 29 Jan 2021 15:15 |
| Last Modified: | 29 Jan 2021 15:15 |
| URI: | http://eprints.bice.rm.cnr.it/id/eprint/20711 |
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