Nuclear Medicine

The study find that the FDG-PET/CT is the current mainstay of lung cancer staging and presents favorable sensitivity and specificity in comparison to morphological diagnostic means especially for mediastinal lymph-node assessment. However; high physiological uptake in the brain requires additional cerebral magnetic resonance imaging to complete M-staging.

Lung cancer staging

Although not a major limitation; the dependency of FDG on blood sugar and the need of preparatory fasting and to recline during the 1-h uptake phase is inconvenient; hampering smooth patient work flow FAPI) have been develop  and are find promising alternatives to FDG in several oncologic indications. Our image presents a FAPI-PET/CT (100 MBq 68GaFAPI-04) acquired 15 min post i.v. injection of a patient with an adenocarcinoma of the lung.

Maximum intensity projection of whole-body (WB-MIP; picture-in-picture) ; and its zoom to the relevant upper body half (big picture) already demonstrate the high tumor-to-background ratios of this promising new tracer in lung; mediastinum and brain. Two brain lesions not delineable on the unenhanced CT performed as part of the PET/CT; one of them with only 8–9 mm in diameter (a); presented FAPI-positive and were confirmed by contrast enhanced cerebral MRI (a, b); however; due to their typical imaging pattern of metastasis no biopsies have been taken.

Several oncologic indications

The histologically validated primary tumor in the right upper lobe but not surrounding pulmonary infiltrates demonstrates a positive FAP-expression (c). A FAPI positive lymph node in regio-4R also demonstrated radiological criteria suspicious for malignancy in contrasten hanced CT (d).

Limited tumor mass with only a small T2a primary tumor and only one potential N2 lymph node metastasis without evidence of bone or visceral metastasis; would not imply high probability of brain lesions and eventually an additional brain MRI might have been omit in such a patient to accelerate curative intended surgery.

Surrounding pulmonary infiltrates

Due to the potential to simplify clinical work-flow and its outstanding low physiological background in normal tissues (including liver and brain); FAPI-PET/CT seems to be a promising imaging probe for oncological patients. However; its true
value in particular clinical indications still needs more detailed evaluation. The radio pharmaceutical was used on an individual patient basis according to German Pharmaceuticals Act §13(2b).

The patient gave written inform consent to receive the novel diagnostics and permitted anonymize publication of relate medical data The ethical committee of Heidelberg University approved this retrospective evaluation to be in accordance with the Helsinki declaration ; (permit S016/2018). For case reports from clinical practice no trial registration is required.