In this single-center , single-blinded prospective randomized trial , 501 patients with body weights of less than 100 kg with suspected acute pulmonary embolism ( PE ) were assigned to normal-dose CTPA ( 100-kVp tube energy and 100-mL CM , 255 patients ) and low-dose CTPA ( 80-kVp tube energy and 75-mL CM , 246 patients ) .