Materials and methods: A total of 40 patients (160 sessions of brachytherapy), unselected brachytherapy out patients at Chulabhorn Hospital, Thailand were enrolled with informed consent and randomized to receive meperidine or fentanyl. Data of perceived pain (according to standard 10-cm visual analog scales [VAS]), and perceived Quality of life (EQ-5D) were collected. Patients and all brachytherapy staffs directly involved with the procedure were blinded about the drug used.