Abstract
Positron emission tomography (PET) scanners have significantly contributed to the advancement of Nuclear Medicine. The integration of PET scanners with computed tomography (CT) and magnetic resonance imaging (MRI) has led to the development of PET/BT and PET/MRI systems, enabling the acquisition of both functional and anatomical information within the same image. The higher soft tissue contrast resolution of MRI compared to CT has improved diagnostic image quality. Additionally, since MRI does not involve ionizing radiation, the radiation dose administered to patients has been reduced. Furthermore, the integrated nature of PET/MRI systems allows for the simultaneous acquisition of axial, coronal, and sagittal sectional images. The dijital nature of the PET module has resulted in higher sensitivity, thereby reducing the amount of radiopharmaceuticals administered to the patient by approximately 50%. However, the longer MRI scanning time compared to CT decreases patient throughput. Moreover, the high cost of PET/MRI systems poses a significant barrier to their widespread adoption.
Keywords: PET/MRI, PET/BT, PET radiation doses, PET imaging, PET image quality
References
Espana S, Fraile L, Herraiz J, Udias J, Desco M, Vaquero J. Performance evaluation of SiPM photodetectors for PET imaging in the presence of magnetic fields. Nucl Instrum Methods Phys Res A. 2010;613:308-316.
Currie GM, Kamvosoulis P, Bushong S. PET/MRI, part 2: technologic principles. J Nucl Med Technol. 2021;49:217-225.
Huang Y, Wang M, Jiang L, et al. Optimal clinical protocols for total-body 18F-FDG PET/CT examination under different activity administration plans. EJNMMI Phys. 2023;10:14.
Rose A. The Visual Process. In: Vision: human and electronic. Boston: Springer US; 1973. p. 1-27.
Øen SK, Aasheim LB, Eikenes L, Karlberg AM. Image quality and detectability in Siemens Biograph PET/MRI and PET/CT systems-a phantom study. EJNMMI Phys. 2019;6:16.
Vandenberghe S, Marsden PK. PET-MRI: a review of challenges and solutions in the development of integrated multimodality imaging. Phys Med Biol. 2015;60:R115-R154.
Schaart DR, Seifert S, Vinke R, et al. LaBr(3):Ce and SiPMs for time-of-flight PET: achieving 100 ps coincidence resolving time. Phys Med Biol. 2010;55:N179-N189.
Martin O, Schaarschmidt BM, Kirchner J, et al. PET/MRI versus PET/CT for whole-body staging: results from a single-center observational study on 1,003 sequential examinations. J Nucl Med. 2020;61:1131-1136.
Brix G, Günther E, Rössler U, et al. Double-strand breaks in lymphocyte DNA of humans exposed to [18F]fluorodeoxyglucose and the static magnetic field in PET/MRI. EJNMMI Res. 2020;10:43.
Fahey FH, Goodkind A, MacDougall RD, et al. Operational and dosimetric aspects of pediatric PET/CT. J Nucl Med. 2017;58:1360-1366.
Kinahan PE, Townsend DW, Beyer T, Sashin D. Attenuation correction for a combined 3D PET/CT scanner. Med Phys. 1998;25:2046-2053.
Burger C, Goerres G, Schoenes S, Buck A, Lonn AH, Von Schulthess GK. PET attenuation coefficients from CT images: experimental evaluation of the transformation of CT into PET 511-keV attenuation coefficients. Eur J Nucl Med Mol Imaging. 2002;29:922-927.
Beyer T, Weigert M, Quick HH, et al. MR-based attenuation correction for torso-PET/MR imaging: pitfalls in mapping MR to CT data. Eur J Nucl Med Mol Imaging. 2008;35:1142-1146.
Andersen FL, Ladefoged CN, Beyer T, et al. Combined PET/MR imaging in neurology: MR-based attenuation correction implies a strong spatial bias when ignoring bone. Neuroimage. 2014;84:206-216.
Mollet P, Keereman V, Bini J, Izquierdo-Garcia D, Fayad ZA, Vandenberghe S. Improvement of attenuation correction in time-of-flight PET/MR imaging with a positron-emitting source. J Nucl Med. 2014;55:329-336.
Liu F, Jang H, Kijowski R, Bradshaw T, McMillan AB. Deep learning MR ımaging-based attenuation correction for PET/MR ımaging. Radiology. 2018;286:676-684.
Krokos G, MacKewn J, Dunn J, Marsden P. A review of PET attenuation correction methods for PET-MR. EJNMMI Phys. 2023;10:52.
Chen Y, Ying C, Binkley MM, et al. Deep learning-based T1-enhanced selection of linear attenuation coefficients (DL-TESLA) for PET/MR attenuation correction in dementia neuroimaging. Magn Reson Med. 2021;86:499-513.
Demir M, Toklu T, Abuqbeitah M, et al. Evaluation of PET scanner performance in PET/MR and PET/CT systems: NEMA tests. Mol Imaging Radionucl Ther. 2018;27:10-18.
Hsu DFC, Ilan E, Peterson WT, Uribe J, Lubberink M, Levin CS. Studies of a next-generation silicon-photomultiplier-based time-of-flight PET/CT system. J Nucl Med. 2017;58:1511-1518.
Peng H, Levin CS. Study of PET intrinsic spatial resolution and contrast recovery improvement for PET/MRI systems. Phys Med Biol. 2012;57:N101-N115.
