Dosimetry Output of CT-Expo and WAZA-ARI in Different Acquisition Parameter of CT Abdomen-Pelvis Examination: A Comparative Study

Abstract

This study aimed to evaluate radiation doses of Computed Tomography Abdomen-Pelvis (CT AP) examinations after implementing optimization protocols and to compare the value of organ equivalent dose (D) and E (E) obtain from both CTExpo (Ver. 2.5, German) and WAZA-ARI (Japan). Six CT AP protocols, one routine (R1) and five modified protocols (R2 to R6) were scrutinize on various CT scanner Canon Aquilion 64-slice (Japan), Siemens Sensation 16 (German) and Siemens Sensation 64 (German). The differences of E value between WAZA ARI and CT-Expo for scanning region between 20 cm to 50 cm were estimated. Furthermore, six organs equivalent dose; lung, liver, gall bladder, gonad or testicles, kidney and stomach were determined and the differences of organ dose between both dose calculators with different CT scanner were analyzed. The highest variation of E between CT-Expo and WAZA ARI is about 27% with average differences observed is around 21%. In term of scanning range, WAZA ARI reported to have large variation of E when compared to CT-Expo. Between different CT scanner, stomach indicate highest D with 80.3 mGy in Canon Acquilion. There was a slight difference between the two softwares but WAZA ARI had overall gave higher reading of E compared to CT-Expo. Our results show that increasing tube potential and reducing pitch factor may increase radiation dose and as increasing scan range of examination also elevate the amount of radiation dose.