Abstract
1280
Background: We investigated the relationship between the semi-quantitative value of F-18 sodium fluoride (18F-NaF) PET/CT and serum ALP of the Castration-resistant Prostate Cancer patients with bone metastases before and after taking Radium-223 dichloride (223RaCl2) therapy.
Methods: From March 2017 to October 2018, 6 castration-resistant Prostate Cancer patients with bone metastases (age 65-77 yrs, median 68 yrs) underwent 18F-NaF PET/CT before initial use of the 223RaCl2 therapy. Three of 6 patients underwent 18F-NaF PET/CT after 6 courses of 223RaCl2 therapies. Average dose of 18F-NaF was 250MBq and whole body scan was performed 60 min after the administration. ALP was measured in all patients before and after receiving 6 courses of therapies. We investigated bone tumor volume (TV10) of each patient as the volume of lesion with SUVmax ≧ 10 using whole body 18F-NaF PET/CT. Total lesion activity (TL10) was defined as multiplication of the SUVmean and TV10. ALP% was defined as the change rate of ALP between before and after the therapies. We investigated the correlation between semi-quantitative values (SUVmax, TV10, and TL10) and ALP and also investigated the correlation between semi-quantitative values (SUVmax, TV10, and TL10) and ALP%.
Results: Weak positive correlations were observed between ALP and each semi-quantitative values and negative correlation were observed between ALP% and each semi-quantitative value. Especially, strong negative correlation was observed between ALP% and SUVmax (R2 = 0.84).
Conclusions: The SUVmax of 18F-NaF PET / CT predicting reduction rate of ALP after the 223RaCl2 therapies for bone metastases of the castration-resistant prostate cancer patients.