Investigation Of Radiation Dose In Conventional CT Examination

Object To investigate the radiation dose in conventional CT examination,seek the factors which affect the radiation dose from standard CT examination protocol.Material and Methods 10 patients were selected for each position which was performed by the SIEMENS SOMATOM Sensation 16 multi-detector CT under standard CT examination protocol,and 5 patients who underwent coronary CTA. Summarize the scanning parameters and radiation doses from different position.Results Under standard CT examination protocol,patients ' CTDIvol and Effective Dose who underwent brain CT scan ranges from 49.25mGy to 54.72mGy and from 1.47 mSv to 1.93mSv respectively.Chest CT:CTDI_volfrom 5.18mGy to 6.24mGy,Effective Dose from 2.35mSv to 3.1mSv.Chest contrast-enhanced CT:from 5.26mGy to 5.88mGy,Effective Dose from 2.06mSv to 3.41mSv.Epigastric contrast-enhanced CT scan:plain scan:CTDI_volfrom 7.91mGy to 9.21mGy,Effective Dose from2.37mSv to 4.41mSv;arterial phase:CTDI_volfrom 9.06mGy to 10.54mGy,Effective Dose from2.75mSv to 5.05mSv;venous phase:CTDI_volfrom 7.91mGy to 9.21mGy,Effective Dose from2.41mSv to 4.41mSv.Pelvis CT scan:plain scan:CTDI_volfrom 3.41mGy to 6.81mGy,Effective Dose froml.3mSv to 2.9mSv;contrast-enhanced scan:CTDI_vol from 3.41mGy to 6.72mGy,Effective Dose from 1.3mSv to 2.9mSv.Coronary CTA: first scan(plain scan)CTDI_volis from 4.08mGy to5.35mGy,Effective Dose is from 0.77mSv to 1.36mSv;second scan(selecting monitoring plane)is 4.21mGy;third scan(monitoring threshold value)is from 29.84mGy to 50.84mGy;fourth scan(contrast-enhanced scan)CTDI_volis 42.82mGy,Effective Dose is from 6.48mSv to 9.24mSv.Conclusion We can conclude that the CTDI_voldetected from patients under standard CT examination protocol is significantly different.Besides patients' factors, there are body height,weight,accepting the scan or not,and so on.Moreover,our radiologists are concerned,because they determine the scan cover,FOV and injection rate.There are various factors affecting radiation dose,and we should think of anthropic factors.