1997 Volume 67 Issue 11 Pages 529-534
CT fluoroscopy is a method of displaying CT images real-time with an ultra-high speed image reorganization system, which conventional CT examinations are unable to do. CT fluoroscopy has contrast resolution superior than that of either fluororoentgenography or ultrasonic fluoroscopy. However, physicians perform paracentesis within areas of radiation beams during fluoroscopy, and are thus exposed to radiation. In this study, we measured the amount of exposure suffered by physicians during CT fluoroscopy. We then used an apparatus designed to hold the puncture needle, which acted to reduce the exposure amount, and measured the exposure dose. Fluoroscopic conditions were set as fllows : tube voltage of 80 kV, tube electric current of 30 mA, for a duration of 10 seconds. The doses of radiation exposure at the hands and fingers (where physicians suffer the greatest radiation exposure) were 0.453mSv/sec inside radiation beams when protective/shield gloves were not used; 0.153mSv/sec when such gloves were used; and 0.001mSv/sec when both puncture needle holders and protective gloves were used. These results confirmed that, with adequate protection ,physicians can safely operate and not exceed the dose limit as stipulated under current laws and as recommended by the ICRP90. Also, to study the radiation exposure of patients, we compared the dose of 10-second CT fluoroscopy with the average dose absorbed during ordinary chest CT examinations. The doses at the phantom center were 3.24mGy and 9.27mGy, respectively, showing that the dose of CT fluoroscopy was about one-third that of ordinary chest CT imaging.
