Technical note: A PET/MR coil with an integrated, orbiting 511 keV transmission source for PET/MR imaging validated in an animal study.
Med Phys
; 49(4): 2366-2372, 2022 Apr.
Article
in En
| MEDLINE
| ID: mdl-35224747
ABSTRACT
BACKGROUND:
MR-based methods for attenuation correction (AC) in PET/MRI either neglect attenuation of bone, or use MR-signal derived information about bone, which leads to a bias in quantification of tracer uptake in PET. In a previous study, we presented a PET/MRI specific MR coil with an integrated transmission source (TX) system allowing for direct measurement of attenuation. In phantom measurements, this system successfully reproduced the linear attenuation coefficient of water.PURPOSE:
The purpose of this study is to validate the TX system in a clinical setting using animals and to show its applicability compared to standard clinical methods.METHODS:
As test subject, a 15-kg piglet was injected with 53 MBq of 18F-NaF. The µ-map obtained with the TX system and the reconstructed activity distribution were compared to four established ACmethods:
a Dixon sequence, an ultra-short echo time (UTE) sequence, a CT scan, and a 511 keV transmission scan using a Siemens ECAT EXACT HR+ as the reference. The PET/MRI measurements were performed on a Siemens Biograph mMR to obtain the µ-map using the TX system as well as the Dixon and UTE sequence directly followed by the CT and ECAT measurements.RESULTS:
The reconstructed activity distribution using the TX system for AC showed similar results compared to the reference (<5% difference in hot regions) and outperformed the MR-based methods as implemented in the PET/MRI system (<10% difference in hot regions). However, the additional hardware of the TX system adds complexity to the acquisition process.CONCLUSION:
Our porcine study demonstrates the feasibility of post-injection transmission scans using the developed TX system in a clinical setting. This makes it a useful tool for PET/MRI in cases where transmission information is needed for AC. Potential applications are studies using larger animals where state-of-the-art atlas-based or artificial intelligence AC methods are not available.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Artificial Intelligence
/
Multimodal Imaging
Limits:
Animals
Language:
En
Journal:
Med Phys
Year:
2022
Document type:
Article
Affiliation country:
Austria