IRCT201208084811N2 IRCT 2013-05-21 Vice chancellor for research, Ahvaz Jundishapour University of Medical Sciences Comparing image quality of low voltage CT angiography with 100 kilovoltage Comparison of image quality of low voltage CT angiography (80 kilovoltage) with standard condition (100 kilovoltage) in patients suspicious to pulmonary emboli 2012-04-20 anticipated 142 Complete https://irct.ir/trial/5162 interventional Randomization: Randomized, Blinding: Triple blinded, Placebo: Not used, Assignment: Parallel, Purpose: Diagnostic, Other design features: Patients are allocated to each group based on block randomization method. Patient, physician (who reports the CT Angiographies) and person who do statistical analysis are all blind to the voltage used in each case. All images are coded by a colleague who is not involved in taking and reporting graphies or analyzing data. So, the study is triple blinded. 1 Pulmonary emboli. Intervention 1: Intervention group: Pulmonary CT Aangiography will be done by 80 kilovoltage condition. Intervention 2: Control group: Pulmonary CT Aangiography will be done by 100 kilovoltage condition.