# First Clinical Experiences with the Ultra-Fast Time-of-Flight BIOGRAPH One Next-Generation Hybrid PET/MRI System

## TL;DR

This paper shares early clinical results using a new ultra-fast PET/MRI system, showing good image quality and potential for broader use.

## Contribution

First clinical evaluation of the BIOGRAPH One PET/MRI system across multiple tracers and body regions.

## Key findings

- PET image quality was rated as good or very good in 93% of scans.
- Diagnostic concordance was observed in 99% of readings.
- Image noise was comparable to digital PET/CT and better than first-generation PET/MRI.

## Abstract

Objective: We present the first clinical experience with the BIOGRAPH One next-generation PET/MRI system scanner, evaluating its performance for body and brain imaging in patients across multiple tracers. Methods: A total of 59 patients were scanned on the BIOGRAPH One PET/MRI following standard clinical PET/CT (n = 52) or first-generation PET/MRI (Biograph mMR, n = 7). Scans comprised 30 total body (TB), whole body (WB), or regional scans with [18F]FDG, and 29 brain scans with either [18F]FDG (n = 5), [18F]FE-PE2I (n = 10), [18F]FET (n = 4), or [68Ga]Ga-DOTATOC (n = 10). The PET image quality was visually assessed using a 5-point Likert scale (1 = very good to 5 = very bad) and compared with clinical scans acquired on either a current-generation digital PET/CT or a first-generation PET/MRI system, including evaluation of diagnostic concordance. PET quantification and image noise was compared in brain and WB/TB [18F]FDG PET scans. Results: PET image quality was rated as good or very good in 93% of scans with a median [inter-quartile range] score of 1.5 [1.5;2]. In 99% of cases, image quality was judged equal to or better than the clinical reference scan (median score 3 [2.5;3]). Diagnostic concordance was observed in 99% of readings. Imaging metrics revealed the anticipated regional bias in brain imaging, while no significant bias was observed in body imaging. Image noise was comparable to that observed with digital PET/CT and demonstrated superiority over first-generation PET/MRI despite potential degradation related to isotope decay in BIOGRAPH One PET/MRI acquisitions scans performed at the end of the imaging workflow. Conclusions: Within the study limitations related to sequential imaging, the BIOGRAPH One PET/MRI scanner demonstrated improved PET sensitivity and workflow potential over its first-generation predecessor, which may allow for broader clinical and research applications.