Fides Schwartz1, Bram Stieltjes2, Zsolt Szucs-Farkas3, André Euler4. 1. Clinic of Radiology and Nuclear Medicine, University Hospital Basel, Basel, Switzerland. Electronic address: fides.schwartz@usb.ch. 2. Clinic of Radiology and Nuclear Medicine, University Hospital Basel, Basel, Switzerland. Electronic address: bram.stieltjes@usb.ch. 3. Institute of Radiology, Hospital Centre of Biel, Biel, Switzerland. Electronic address: zsolt.szuecs@szb-chb.ch. 4. Clinic of Radiology and Nuclear Medicine, University Hospital Basel, Basel, Switzerland. Electronic address: andre.euler@duke.edu.
Abstract
OBJECTIVES: Compare incidence of over-scanning in chest CT among six hospitals and impact on effective and organ effective radiation dose. METHODS: Scout images of 600 chest CTs from six hospitals (A-F) were retrospectively reviewed using a radiation dose tracking software (RTS). Optimal scan range was determined and compared to the actual scan range. Incidence of cranial and caudal over-scanning was assessed and changes in total and organ effective dose were calculated. Descriptive statistics, Tukey- and Wilcoxon matched pairs test were applied. RESULTS: Simultaneous cranial and caudal over-scanning occurred in 29 of 600 scans (A = 0%, B = 1%, C = 12%, D = 3%, E = 11%, F = 2%). Effective radiation dose increased on average by 0.29 mSv (P < 0.001). Cranial over-scanning was observed in 45 of 600 scans (A = 0%, B = 8%, C = 2%, D = 15%, E = 17%, F = 3%) and increased organ effective dose by 0.35 mSv in the thyroid gland (P < 0.001). Caudal over-scanning occurred in 147 of 600 scans (A = 7%, B = 9%, C = 35%, D = 4%, E = 32%, F = 60%) and increased organ effective doses in the upper abdomen by up to 14% (P < 0.001 for all organs). CONCLUSIONS: Substantial differences in the incidence of over-scanning in chest CT exist among different hospitals. These differences result in excessive effective radiation dose and increased individual organ effective doses in patients.
OBJECTIVES: Compare incidence of over-scanning in chest CT among six hospitals and impact on effective and organ effective radiation dose. METHODS: Scout images of 600 chest CTs from six hospitals (A-F) were retrospectively reviewed using a radiation dose tracking software (RTS). Optimal scan range was determined and compared to the actual scan range. Incidence of cranial and caudal over-scanning was assessed and changes in total and organ effective dose were calculated. Descriptive statistics, Tukey- and Wilcoxon matched pairs test were applied. RESULTS: Simultaneous cranial and caudal over-scanning occurred in 29 of 600 scans (A = 0%, B = 1%, C = 12%, D = 3%, E = 11%, F = 2%). Effective radiation dose increased on average by 0.29 mSv (P < 0.001). Cranial over-scanning was observed in 45 of 600 scans (A = 0%, B = 8%, C = 2%, D = 15%, E = 17%, F = 3%) and increased organ effective dose by 0.35 mSv in the thyroid gland (P < 0.001). Caudal over-scanning occurred in 147 of 600 scans (A = 7%, B = 9%, C = 35%, D = 4%, E = 32%, F = 60%) and increased organ effective doses in the upper abdomen by up to 14% (P < 0.001 for all organs). CONCLUSIONS: Substantial differences in the incidence of over-scanning in chest CT exist among different hospitals. These differences result in excessive effective radiation dose and increased individual organ effective doses in patients.