The present invention provides a diagnostic agent for a therapeutic effect on cancer, containing a compound represented by formula (1-0).(In formula (1-0), R represents —O(CH2)n—, —O(CH2)nOC2H4—, —CH2O(CH2)n—, or —CH2O(CH2)nOC2H4—, n represents an integer of 1 to 5, and Q1 represents F or —OCH3.)