Viabilidad de la PET/TC con 18F-fluciclovina para identificar metástasis cerebrales

Patients with recently diagnosed brain metastatic lesion(s) will be recruited based on MRI with or without histological confirmation, per standard of care. All patients will undergo an 18F-fluciclovine head PET/CT scan prior to treatment for brain metastatic lesions, post treatment, and 3 years post treatment.

PET/CT protocol:

All patients will be instructed to fast for 4 hr. prior to the scan. CT imaging of the head will be performed using GE Discovery MI Digital PET/CT (Boston, Massachusetts) prior to the injection of 18F-fluciclovine. While the patient is in a supine position on the PET table, 5 mCi (185 MBq) of 18F-fluciclovine will be administrated intravenously, followed by a saline flush. At the time of the injection, a continuous dynamic PET images lasting 60 min will be performed using 3D-dynamic and list-mode acquisition: 2.0 mm slice thickness, number of frames(f) x time in seconds(s) and minutes(m) of: 4f x 15s, 4f x 30s, 6f x 2m, 5f x 3m, and 6f x 5m. PET images at 0-5 (flow), 15-25 (early), 25-35 (mid), 45-60 min (delayed) post-injection will be reconstructed using Qclear 500 and OSEM iterative reconstruction with TOF (VPFX): 8 iterations, 5 subsets, 440 image matrix, 4 mm Gaussian filter, TOF. [24, 27].

The primary objective is to evaluate whether anti-3-[18F]FACBC (FACBC, fluciclovine, Axumin) uptake (measured by standardized uptake values, SUV, and visualized uptake) in brain metastatic lesions is above normal brain background. We will evaluate scan results, against positive histology confirmation or confirmatory MRI images.

As a second phase of this study 20 patients who underwent baseline PET/CT will undergo a second 18F-fluciclovine PET/CT to evaluate 18F-fluciclovine uptake in treated lesions over 60 minutes. Uptake within the lesions and the benign brain parenchyma will be plotted on a 60 min time activity curve. Absolute SUV values will be compared with contralateral normal brain, cerebellum, pituitary gland, and superior sagittal sinus (SSS)[1]. We hypothesize that uptake of lesions with complete response will demonstrate significant reduction of uptake with persistent mild uptake above the pituitary gland. Focal uptake will be considered as residual viable disease. Truth will be corelated with histology confirmation, Standard of care (SOC) images, and or follow up.

For this Aim, 10 patients who underwent localized brain lesion/s management and are presenting with intermediate surveillance MRI results for true local recurrence or radionecrosis will undergo a 3rd 18F-fluciclovine PET/CT to evaluate the use of 18F-fluciclovine to delineate true progression from radionecrosis.

The investigators will evaluate scan results, against positive histology confirmation or confirmatory follow up with standard of care images.