Fig. 4.

Representative imaging of patients with at least one ¹⁸F-FES-negative lesion. A Only ¹⁸F-FES-negative lesions (Fig. 2, #43). This 50-year-old woman had 4 ¹⁸F-FDG-positive lesions in her chest wall and lymph nodes, but all were negative on ¹⁸F-FES PET. She was on palbociclib combined with letrozole as first-line treatment for 2.3 months until progression occurred. B Presence of ¹⁸F-FES-positive and ¹⁸F-FES-negative lesions (Fig. 2, #49). This 53-year-old woman had innumerable ¹⁸F-FDG-positive and ¹⁸F-FES-positive lesions in the pleura, lung, lymph nodes, and bone, but the left chest wall metastasis showed outstanding uptake of ¹⁸F-FDG but not of ¹⁸F-FES. She was on palbociclib combined with fulvestrant as third-line treatment for 5.6 months until progression occurred