Objective: Intermittent CT fluoroscopic biopsy is a new technology, but has not been studied widely. This study aims to investigate correlation between the radiation dose and fluoroscopic CT exposure factors to establish the low dose parameters for performing percutaneous lung biopsies, as well as the relationship of the mean diameter and depth of lesions with radiation dose, procedure time, success and complication rates.
Materials and methods: This is a retrospective study to analyse lung biopsies performed using intermittent CT fluoroscopic technique with 18 G semi-automated coaxial gun on 256 slice scanner. A total of 50 patients were included in the study. Biopsy was done in three mAs and KVp settings (30 and 70, 10 and 120, 30 and 120, respectively). The statistical data analysis was performed using SPSS Statistics software.
Results: Pneumothorax occurred in 22 % of cases. Sampling rate was 98% but histopathological diagnosis was made in 94% cases. Mean procedure time was 30.5±11.1 minutes. Low dose protocol (30 mAs and 70 KVp) had least radiation exposure during biopsy procedure (p < 0.001) with similar success rate, complications and procedure time (p > 0.05) in comparison with high dose protocol (10 and 120, 30 and 120 mAs and KVp, respectively). Mean diameter of lesions didn't correlate with radiation dose, success rate, complications and duration of procedure (p > 0.05) while significant association was found when depth was correlated with radiation exposure during fluoroscopic biopsy, duration of procedure and complication rates (p < 0.05) while no association was found with success rates.
Conclusion: On third generation dual energy source CT scanner, reducing mAs and KVp to 30 and 70 during fluoroscopy biopsy can produce images whose complications and success rates are comparable to high dose CT. In general, intermittent CT fluoroscopy guided lung biopsy has good success rates with acceptable complications, while utilising less radiation dose and procedure time.
Keywords: Computed tomography (CT); biopsy; dose length product (DLP); fluoroscopy; intermittent; lung; radiation.