Long axial field-of-view PET/CT devices: are we ready for the technological revolution?

Figures & data

Figure 1. An example of ¹⁸F-FDG Maximum Intensity Projection (MIP) images obtained by dynamic acquisition with a LAFOV PET/CT scanner (Biograph Vision Quadra, Siemens Healthineers) in a patient with metastatic melanoma and several lesions in the thoracic area (image courtesy of Prof. Antonia Dimitrakopoulou-Strauss).

Table 1. Schematization of the main technical features of PET/CT scanners mentioned in the manuscript.

PET/CT scanner	Type	FOV (cm)	Scintillators	Detectors	Injection Dose (^18F-FDG)	Possibility of Fast protocols	Sensitivity	Spatial res. (axial FWHM, mm)	TOF resolution (ps)
Biograph-mCT [11,12] (Siemens Healthineers)	Analogue	22.1	LSO	PMTs	Standard (3.7 MBq/kg)	Unscheduled	9.6 kcps/MBq	4.3	540
Biograph Vision 600 [13,14] (Siemens Healthineers)	Digital	26.3	LSO	SiPMs	Standard (3.7 MBq/kg)	Fast protocols reported as feasible	16.4 kcps/MBq	3.5	210
Biograph Vision Quadra [17,28] (Siemens Healthineers)	LAFOV	106	LSO	SiPMs (analog.)	Standard (3.7 MBq/kg) Low-dose (1.85 MBq/kg) Ultra-low (0.37 MBq/kg)	Fast protocols reported as feasible	83.4 kcps/MBq	3.4	219
PennPET Explorer [17,28] (UPenn, KAGE Medical, Philips)	LAFOV	64	LYSO	SiPMs	Standard (3.7 MBq/kg) Low-dose (1.85 MBq/kg) Ultra-low (0.37 MBq/kg)	Fast protocols reported as feasible	55 kcps/MBq	4.0	250
uEXPLORER [17,28] (United Imaging Healthcare)	LAFOV	194	LYSO	SiPMs (analog.)	Standard (3.7 MBq/kg) Low-dose (1.85 MBq/kg) Ultra-low (0.37 MBq/kg)	Fast protocols reported as feasible	174 kcps/MBq	3.0	505

TB-PET/CT: total-body PET/CT; ¹⁸F-FDG: ¹⁸F-fluorodeoxyglucose; LSO: lutetium oxyorthosilicate; LAFOV: long axial field of view; LYSO: lutetium-yttrium oxyorthosilicate; TOF: time-of-flight

Table 2. Summary of the cited papers on the applications of TB-PET/CT in oncological and non-oncological fields.

Author	Year/Country	Employed TB-PET/CT scanner	Radioph	Setting	Comment
Hu et al. [17]	2022/ China	uEXPLORER (United Imaging Healthcare)	^18F-FDG	Retrospective Staging of patients (n = 78) with hepatic tumors	Fast 2-min scan (G2) showed the same detection rate of hepatic tumors than 15-min (G15) standard protocol, but missed 3 pathological nodes
Chen et al. [19]	2022/ China	uEXPLORER (United Imaging Healthcare)	^18F-FDG	Retrospective Diagnostic performance of TB-PET/CT at half-dose in a pediatric cohort (n = 100)	TB-PET/CT with tracer half-dose (1.85 MBq/kg) is feasible in pediatric patients, also when fast-scan protocol (60-s) is employed
Wang et al. [22]	2022/China	uEXPLORER (United Imaging Healthcare)	^18F-FDG	Prospective Feasibility of dynamic TB-PET/CT in lung cancer patients (n = 30)	According dynamic TB-PET/CT data, patients with newly diagnosed lung cancer were divided into fast (F-DFM) and slow (S-DFM) metabolic groups, the former had more homogeneous uptake and also showed intra-tumoral immune cell infiltration
Alberts et al. [27]	2022/Switzerland	Biograph Vision Quadra (Siemens Healthineers)	^68Ga-PSMA-11	Retrospective Feasibility of late-time point scan in prostate cancer patients (n = 10)	^68Ga-PSMA-11 TB-PET/CT performed at 4 h provides higher TBR and SNR with respect to standard acquisition protocol at 1 h post injection
Strauss et al. [28]	2021/ Germany	Biograph Vision Quadra (Siemens Healthineers)	^68Ga-PSMA-11	Retrospective Usefulness of TB-PET/CT dynamic acquisition in prostate cancer recurrence	Dynamic acquisition identified a time window in the first 10 min, suitable for identification of biochemical recurrence
Abdelhafez et al. [30]	2022/ United States	uEXPLORER (United Imaging Healthcare)	^18F-FDG	Prospective Feasibility of TB-PET/CT with ultra-low dose in patients with autoimmune arthritis (n = 30)	TB-PET/CT at ultra-low dose (78.1 ± 4.7 MBq) was feasible for assessing inflammatory involvement of joints in patients with autoimmune inflammatory arthritides and correlated with rheumatologic findings

TB-PET/CT: total-body PET/CT; ¹⁸F-FDG: ¹⁸F-fluorodeoxyglucose; PSMA: prostate specific membrane antigen; FOV: field of view; TBR: tumor-to-background ratio; SNR: signal-to-noise ratio;

Jakoby BW, Bercier Y, Conti M, et al. Physical and clinical performance of the mCT time-of-flight PET/CT scanner. Phys Med Biol. 2011;56(8):2375–2389.

 PubMed Web of Science ®Google Scholar

Rausch I, Cal-González J, Dapra D, et al. Performance evaluation of the Biograph mCT Flow PET/CT system according to the NEMA NU2-2012 standard. EJNMMI Phys. 2015;2(1):26.

 PubMedGoogle Scholar

Carlier T, Ferrer L, Conti M, et al. From a PMT-based to a SiPM-based PET system: a study to define matched acquisition/reconstruction parameters and NEMA performance of the biograph vision 450. EJNMMI Physics. 2020;7(1):55.

 PubMed Web of Science ®Google Scholar

van Sluis J, de Jong J, Schaar J, et al. Performance characteristics of the digital biograph vision PET/CT system. J Nucl Med. 2019;60(7):1031–1036.

 PubMed Web of Science ®Google Scholar

Katal S, Eibschutz LS, Saboury B, et al. Advantages and applications of total-body PET scanning. Diagnostics. 2022;12(2):426.

 Web of Science ®Google Scholar

Yu H, Gu Y, Fan W, et al. Expert consensus on oncological [18F]FDG total-body PET/CT imaging (version 1). Eur Radiol. 2022. DOI:10.1007/s00330-022-08960-8.

 Web of Science ®Google Scholar

Prenosil GA, Sari H, Fürstner M, et al. Performance characteristics of the biograph vision quadra PET/CT system with a long axial field of view using the NEMA NU 2-2018 standard. J Nucl Med. 2022;63(3):476–484.

 PubMed Web of Science ®Google Scholar

Hu Y, Liu G, Yu H, et al. Diagnostic performance of total-body 18F-FDG PET/CT with fast 2-min acquisition for liver tumours: comparison with conventional PET/CT. Eur J Nucl Med Mol Imaging. 2022;49(10):3538–3546.

 PubMed Web of Science ®Google Scholar

Wang D, Zhang X, Liu H, et al., Assessing dynamic metabolic heterogeneity in non-small cell lung cancer patients via ultra-high sensitivity total-body [18F]FDG PET/CT imaging: quantitative analysis of [18F]FDG uptake in primary tumors and metastatic lymph nodes. Eur J Nucl Med Mol Imaging. 2022;49(13): 4692–4704.

 PubMed Web of Science ®Google Scholar

Fendler WP, Bluemel C, Czernin J, et al. PET imaging in prostate cancer, future trends: PSMA ligands. Clin Transl Imaging. 2016;4(6):467–472.

 Google Scholar