Abstract
The goal of this work is to further improve positron emission tomography (PET) attenuation correction and magnetic resonance (MR) sensitivity for head and neck applications of PET/MR. A dedicated 24-channel receive-only array, fully-integrated with a hydraulic system to move a transmission source helically around the patient and radiofrequency (RF) coil array, is designed, implemented, and evaluated. The device enables the calculation of attenuation coefficients from PET measurements at 511 keV including the RF coil and the particular patient. The RF coil design is PET-optimized by minimizing photon attenuation from coil components and housing. The functionality of the presented device is successfully demonstrated by calculating the attenuation map of a water bottle based on PET transmission measurements; results are in excellent agreement with reference values. It is shown that the device itself has marginal influence on the static magnetic field B0 and the radiofrequency transmit field B1 of the 3T PET/MR system. Furthermore, the developed RF array is shown to outperform a standard commercial 16-channel head and neck coil in terms of signal-to-noise ratio (SNR) and parallel imaging performance. In conclusion, the presented hardware enables accurate calculation of attenuation maps for PET/MR systems while improving the SNR of corresponding MR images in a single device without degrading the B0 and B1 homogeneity of the scanner.
Highlights
Multi-modality imaging provides valuable information for patient diagnosis
The combination of positron emission tomography (PET) with magnetic resonance imaging (MRI) is very promising [1,2,3], as MRI examinations are highly complementary to PET, offering a wide range of high-contrast imaging sequences without employing additional ionizing radiation
The combination of PET and MRI represents a major challenge for molecular imaging technology, regarding the development of PET-compatible radiofrequency (RF) coils for MR signal detection, and the implementation of novel attenuation correction (AC) methods, which do not rely on the availability of computed tomography (CT)-like transmission information
Summary
The combination of positron emission tomography (PET) with magnetic resonance imaging (MRI) is very promising [1,2,3], as MRI examinations are highly complementary to PET, offering a wide range of high-contrast imaging sequences without employing additional ionizing radiation. The combination of PET and MRI represents a major challenge for molecular imaging technology, regarding the development of PET-compatible radiofrequency (RF) coils for MR signal detection, and the implementation of novel attenuation correction (AC) methods, which do not rely on the availability of computed tomography (CT)-like transmission information. In PET/MR systems, the RF coils are located within the PET field-of-view (FOV), and may degrade PET image quality due to additional attenuation and scatter. The design and development of RF coil arrays for integrated PET/MR systems poses new challenges and requirements compared to MR-only applications. Photon attenuation due to the RF coil itself has to be minimized, and the remaining effect should be characterized precisely so as to enable efficient data correction [6,7]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
