Pharmacokinetic Evaluation of Fibroblast Activation Protein-Targeted Radiopharmaceutical Uptake in Low-Stage…

Cohort studyCancer biotherapy & radiopharmaceuticals· Aug 2026

Pharmacokinetic Evaluation of Fibroblast Activation Protein-Targeted Radiopharmaceutical Uptake in Low-Stage Rectal Cancer Tumor Microenvironment.

XuDong Zhang, Ke Duan, YuHan Long, Tong Zhou

Nuclear & Molecular ImagingCohort studyQ2IF 1.9

Most rectal cancer patients reached tumor-ablative radiation doses with 177Lu-FAPI therapy

Pharmacokinetic Evaluation of Fibroblast Activation Protein-Targeted Radiopharmaceutical Uptake in Low-Stage Rectal Cancer Tumor Microenvironment.

XuDong Zhang … Tong Zhou

Cancer biotherapy & radiopharmaceuticals · Aug 2026 · Q2 in Radiology

Purpose

Radionuclide therapy targeting fibroblast activation protein (fibroblast activation protein) offers an effective treatment for tumors with high fibroblast activation protein expression, such as those imaged with 68 Ga-fibroblast activation protein inhibitor (FAPI) and treated with 177 Lu-FAPI.

Methods

A cohort of 26 patients (mean age: 56.3 ± 9.2 years) with stage I-II rectal cancer underwent 68 Ga-FAPI positron emission tomography/computed tomography imaging after intravenous injection of 68 Ga-FAPI (150-250 MBq).

n = 26 patients

Results

92.3%

92.3% of patients hit at least 20 Gy tumor dose, a treatment-level target

n = 26 patients

More results

SUV max ranged from 8.5 to 12.5, with imaging performed at multiple time points (10, 30, 60, and 120 min) to capture tracer kinetics.

Activity scaling was applied to estimate tumor doses with 3-7 GBq of 177 Lu-FAPI.

Kidney dosages ranged from 2.2 to 5.0 Gy, whereas liver doses varied from 1.7 to 4.1 Gy.

More results

SUV max showed a high correlation with absorbed dose ( r = 0.88, p < 0.001).

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Conclusion · 1 of 2

The methodology successfully enhanced tumor dose coverage while ensuring organ safety through activity optimization.

Conclusion · 2 of 2

This system offers a clinically applicable approach to targeted radionuclide therapy by combining positron emission tomography imaging, pharmacokinetics, and dosimetry to deliver optimal tumor doses while meeting organ-at-risk constraints.

Pharmacokinetic Evaluation of Fibroblast Activation Protein-Targeted Radiopharmaceutical Uptake in Low-Stage Rectal Cancer Tumor Microenvironment.

Pharmacokinetic Evaluation of Fibroblast Activation Protein-Targeted Radiopharmaceutical Uptake in Low-Stage Rectal Cancer Tumor Microenvironment.

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