Abstract
534
Purpose: The aim of this study was to evaluate 223Ra therapy on prostate cancer with bone metastases by 18F-fluoride PET/CT, 18F-FDG PET/CT, bone scintigraphy/SPECT, and follow-up.
Methods: Ten patients with bone metastases of prostate cancer were retrospectively enrolled. As the treatment with 223Ra, 55kBq/kg 223Ra was intravenously injected. 223Ra treatment was performed every 4 weeks 6 times. Before the start of 223Ra treatment and after 6th treatment, the patients were assessed by 18F-fluoride PET/CT, 18F-FDG PET/CT, bone scintigraphy/SPECT. 18F-fluoride PET/CT and 18F-FDG PET/CT were performed 60 minutes after intravenous administration of 2.1MBq/kg of 18F fluoride or 3.7MBq/kg of 18F-FDG using a PET/CT camera (Biograph 16 or Biograph Horizon, Siemens). Bone scintigraphy/SPECT was performed 3 hours after intravenous administration of 740MBq of 99mTc-MDP or 99mTc-HMDP using gamma camera (Symbia T, Siemens). ROIs were drawn on the areas of bone metastases, and the maximal standardized uptake value (SUVmax) within ROIs was measured. PSA levels were compared before and after 223Ra therapy.
Results: Improvement of bone metastases and decrease in SUVmax confirmed after 223Ra therapy in 8 patients. Deterioration of bone metastases was observed in 2 patients. Bone metastases were more efficiently detected by 18F-fluoride PET/CT than bone scintigraphy/SPECT. The activity of bone metastases was more efficiently detected by 18F-FDG PET/CT than others. PSA levels were increased in 7 patients after 223Ra therapy.
Conclusions: The reducing effect of 223Ra on bone metastases was confirmed by 18F-fluoride PET/CT, 18F-FDG PET/CT, and bone scintigraphy/SPECT in 8 of the 10 patients with bone metastases of prostate cancer, although PSA levels were elevated in 7 of the patients after 223Ra therapy.