Evaluating the tumour detection efficacy of [18F]Fluorthanatrace positron emission tomography in a metastatic lung cancer animal model.

Lung cancer is a leading cause of cancer-related mortality worldwide, with high metastatic potential and limited imaging tools for guiding targeted therapies. Poly(ADP-ribose) polymerase (PARP)-1 is overexpressed in multiple malignancies and represents a promising target for molecular imaging. Here, we evaluated the feasibility and specificity of [18F]Fluorthanatrace ([18F]FTT), a radiolabeled PARP inhibitor analogue, for noninvasive detection of lung cancer metastases in a syngeneic mouse model. Lung metastases were established by intravenous injection of LL/2 cells into C57BL/6 mice, followed by micro-CT and dynamic/static PET imaging. [18F]FTT showed high radiochemical purity (>99%) and remained stable in vitro. Dynamic PET identified 30-45 min postinjection as the optimal imaging window (tumour-to-lung ratio: 2.15 ± 0.10). Tumour uptake was significantly reduced by pre-administration of olaparib, confirming PARP-1-specific binding. Ex vivo autoradiography and immunohistochemistry demonstrated colocalization of tracer uptake with PARP-1 expression. Together, these results support the translational potential of [18F]FTT PET imaging for detecting PARP-1-expressing lung metastases in precision oncology.