Azad GK, et al. - Compared to SUV_max and SUV_mean, researchers ascertained if noninvasive measurement of changes in ¹⁸F-fluoride metabolic flux to bone mineral (K_i) by PET/CT could deliver incremental value in response assessment of bone metastases in breast cancer. For this analysis, they included 12 breast cancer patients beginning endocrine treatment for de novo or progressive bone metastases. According to findings, K_i differentiated progressive disease (PD) from non-PD more reliably than did SUV_max and SUV_mean after 8 weeks of endocrine treatment for bone-predominant metastatic breast cancer. This may have been because measuring SUV underestimates fluoride clearance by not considering changes in input function.