Radiation dose reduction via sinogram affirmed iterative reconstruction and automatic tube voltage modulation (CARE kV) in abdominal CT.
OBJECTIVE
To evaluate the feasibility of sinogram-affirmed iterative reconstruction (SAFIRE) and automated kV modulation (CARE kV) in reducing radiation dose without increasing image noise for abdominal CT examination.


MATERIALS AND METHODS
This retrospective study included 77 patients who received CT imaging with an application of CARE kV with or without SAFIRE and who had comparable previous CT images obtained without CARE kV or SAFIRE, using the standard dose (i.e., reference mAs of 240) on an identical CT scanner and reconstructed with filtered back projection (FBP) within 1 year. Patients were divided into two groups: group A (33 patients, CT scanned with CARE kV); and group B (44 patients, scanned after reducing the reference mAs from 240 to 170 and applying both CARE kV and SAFIRE). CT number, image noise for four organs and radiation dose were compared among the two groups.


RESULTS
Image noise increased after CARE kV application (p < 0.001) and significantly decreased as SAFIRE strength increased (p < 0.001). Image noise with reduced-mAs scan (170 mAs) in group B became similar to that of standard-dose FBP images after applying CARE kV and SAFIRE strengths of 3 or 4 when measured in the aorta, liver or muscle (p ≥ 0.108). Effective doses decreased by 19.4% and 41.3% for groups A and B, respectively (all, p < 0.001) after application of CARE kV with or without SAFIRE.


CONCLUSION
Combining CARE kV, reduction of mAs from 240 to 170 mAs and noise reduction by applying SAFIRE strength 3 or 4 reduced the radiation dose by 41.3% without increasing image noise compared with the standard-dose FBP images.
['Shin|Hyun Joo|HJ|', 'Chung|Yong Eun|YE|', 'Lee|Young Han|YH|', 'Choi|Jin-Young|JY|', 'Park|Mi-Suk|MS|', 'Kim|Myeong-Jin|MJ|', 'Kim|Ki Whang|KW|']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D000465:Algorithms D004867:Equipment Design D005260:Female D006801:Humans D008297:Male D008875:Middle Aged D061330:Multidetector Computed Tomography D011829:Radiation Dosage D011832:Radiation Injuries D011857:Radiographic Image Interpretation, Computer-Assisted D011860:Radiography, Abdominal D012189:Retrospective Studies
Radiation dose reduction Iterative reconstruction Tube voltage modulation Computed tomography