PETMRT

PETMRT is a hybrid medical imaging modality that combines positron emission tomography (PET) with magnetic resonance tomography (MRT) to enable simultaneous acquisition of metabolic information and high-resolution MRT-based anatomical and functional imaging. The term is used in some texts as a variant of PET/MRT; most literature uses PET/MRT or PET-MRT.

In PETMRT systems, PET detectors are integrated with an MRT scanner to allow concurrent PET and MRT imaging. Detectors must operate in strong magnetic fields; advances such as time-of-flight PET and multi-channel MRT coils improve localization and image quality. MRT-based attenuation correction uses MRT images to estimate photon attenuation, with methods including Dixon or UTE-based segmentation and atlas- or machine-learning approaches; bone representation remains challenging.

Advantages include reduced radiation exposure relative to PET/CT, superior soft-tissue contrast from MRT, and the ability to acquire complementary data in a single session. Applications span neurology (neurodegenerative disease mapping, epilepsy), oncology (tumor detection, staging, treatment response), and cardiology (viability and fibrosis assessment). Limitations include higher cost, longer scan times, MRT safety constraints (implants, claustrophobia), complexities of attenuation correction, and susceptibility to motion and metal artifacts.

History and development: Hybrid PET-MRT platforms appeared in the late 2000s; initial clinical systems in the early 2010s, with ongoing improvements in detectors, software, and workflows. Research directions include multimodal biomarkers, advanced MRT sequences, and robust attenuation correction. As of now, PETMRT is a terminology variant for PET-MRT, with adoption in research and select clinical centers.