Objective Gallium-68-labelled fibroblast activation protein inhibitor ([68 Ga]Ga-FAPI) is a tumour-stromal imaging agent showing complementary value alongside fluorine-18 fluorodeoxyglucose ([18F]FDG) in cancer imaging. This study investigated the feasibility of a same-day dual-tracer positron emission tomography/computed tomography (PET/CT) protocol with [68 Ga]Ga-FAPI-04 following [18F]FDG in patients presenting with negative or equivocal [18F]FDG. Methods Patients with negative or equivocal [18F]FDG findings underwent dual-tracer PET/CT (named FDG-mixed FAPI PET/CT, abbreviated to mFAPI PET/CT) on the same day, with [68 Ga]Ga-FAPI-04 administered 4.0–7.75 h following [18F]FDG injection. Lesion detection rates and lesion-to-background uptake ratios (LBRs) were compared between [18F]FDG and mFAPI PET/CT. Results Forty-four patients were included in the analysis. The mFAPI PET was superior to [18F]FDG PET for primary tumour detection (86.2% [25/29] vs. 37.9% [11/29], P < 0.001), and showed higher LBRs (P < 0.001) in various types of cancer. For metastatic lesions detection, mFAPI PET yielded a greater number of positive lesions (90.3% [317/351] vs. 44.7% [157/351], P < 0.001) and higher LBRs than [18F]FDG in most lesions, especially in lymph node, peritoneal, and liver metastases (all P < 0.05). The mFAPI PET/CT scans had a prominent impact on patients with negative or equivocal [18F]FDG in different clinical situations, including characterizing suspicious lesions in 88.9% (8/9), locating the primary site in 46.2% (6/13), upgrading of tumour staging in 81.8% (9/11), and identification of recurrence in 81.8% (9/11). Conclusions A same-day dual-tracer PET/CT protocol with [68 Ga]Ga-FAPI-04 following [18F]FDG is feasible for enhancing the ability to identify indeterminate lesions, localize unknown malignant primary tumour sites, and accurately provide staging and restaging in patients presenting with negative or equivocal [18F]FDG. Trial registration NCT05034146. Registered February 23, 2021.

Same-day dual-tracer PET/CT imaging with [⁶⁸ Ga]Ga-FAPI-04 following [¹⁸F]FDG finds answers in patients presenting with negative or equivocal [¹⁸F]FDG

期刊论文
发表日期：

2025年7月4日

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Hongyan Li,
Chongjiao Li,
Yueli Tian,
Zhiwei Xiao,
Diankui Xing,
Yong He

摘要

Objective

Gallium-68-labelled fibroblast activation protein inhibitor ([⁶⁸ Ga]Ga-FAPI) is a tumour-stromal imaging agent showing complementary value alongside fluorine-18 fluorodeoxyglucose ([¹⁸F]FDG) in cancer imaging. This study investigated the feasibility of a same-day dual-tracer positron emission tomography/computed tomography (PET/CT) protocol with [⁶⁸ Ga]Ga-FAPI-04 following [¹⁸F]FDG in patients presenting with negative or equivocal [¹⁸F]FDG.

Methods

Patients with negative or equivocal [¹⁸F]FDG findings underwent dual-tracer PET/CT (named FDG-mixed FAPI PET/CT, abbreviated to mFAPI PET/CT) on the same day, with [⁶⁸ Ga]Ga-FAPI-04 administered 4.0–7.75 h following [¹⁸F]FDG injection. Lesion detection rates and lesion-to-background uptake ratios (LBRs) were compared between [¹⁸F]FDG and mFAPI PET/CT.

Results

Forty-four patients were included in the analysis. The mFAPI PET was superior to [¹⁸F]FDG PET for primary tumour detection (86.2% [25/29] vs. 37.9% [11/29], P < 0.001), and showed higher LBRs (P < 0.001) in various types of cancer. For metastatic lesions detection, mFAPI PET yielded a greater number of positive lesions (90.3% [317/351] vs. 44.7% [157/351], P < 0.001) and higher LBRs than [¹⁸F]FDG in most lesions, especially in lymph node, peritoneal, and liver metastases (all P < 0.05). The mFAPI PET/CT scans had a prominent impact on patients with negative or equivocal [¹⁸F]FDG in different clinical situations, including characterizing suspicious lesions in 88.9% (8/9), locating the primary site in 46.2% (6/13), upgrading of tumour staging in 81.8% (9/11), and identification of recurrence in 81.8% (9/11).

Conclusions

A same-day dual-tracer PET/CT protocol with [⁶⁸ Ga]Ga-FAPI-04 following [¹⁸F]FDG is feasible for enhancing the ability to identify indeterminate lesions, localize unknown malignant primary tumour sites, and accurately provide staging and restaging in patients presenting with negative or equivocal [¹⁸F]FDG.

Trial registration

NCT05034146. Registered February 23, 2021.

Same-day dual-tracer PET/CT imaging with [68 Ga]Ga-FAPI-04 following [18F]FDG finds answers in patients presenting with negative or equivocal [18F]FDG

摘要

Same-day dual-tracer PET/CT imaging with [⁶⁸ Ga]Ga-FAPI-04 following [¹⁸F]FDG finds answers in patients presenting with negative or equivocal [¹⁸F]FDG