Fig. 2

Bone density changes suggest tumor response in bone metastases. A 42-year-old man was diagnosed with lung adenocarcinoma and bone metastases. A Pretreatment axial CT scan in the bone window shows two osteolytic metastases (both lesions with diameters of 10 mm) (white arrows) in thoracic vertebrae. B, C The osseous lesions have not significantly changed in the sum of longest diameters according to RECIST 1.1 but show osteosclerotic reaction (white arrows) in 6 months (B) and 10 months (C) after targeted therapy with afatinib, an epidermal growth factor receptor (EGFR) - tyrosine kinase inhibitor (TKI), representing good response. D, E Skeletal scintigraphy shows significantly decreased uptake of radiotracer after comparison between pretreatment (D) and posttreatment (E) images, which confirmed good therapeutic response