UCSF

Background

Computed-tomography-guided interventions are attractive for tissue sampling of pediatric bone lesions; however, it comes with exposure to ionizing radiation, inherent to CT and magnified by multiple passes during needle localization.

Objective

We evaluate a method of CT-guided bone biopsy that minimizes ionizing radiation exposure by lowering CT scanner tube current (mAs) and voltage (kVp) during each localization scan.

Materials and methods

We retrospectively reviewed all CT-guided bone biopsies (n = 13) over a 1-year period in 12 children. Three blinded readers identified the needle tip on the reduced-dose CT images (mAs = 50, kVp = 80) during the final localization scan at biopsy and rated the image quality as high, moderate or low.

Results

The image quality of the reduced-dose scans during biopsy was rated as either high or moderate, with needle tip visualized in 12 out of 13 biopsies. Twelve of 13 biopsies also returned sufficient sample for a pathological diagnosis. The average savings in exposure using the dose-reduction technique was 87%.

Conclusion

Our results suggest that a low mAs and kVp strategy for needle localization during CT-guided bone biopsy yields a large dose reduction and produces acceptable image quality without sacrificing yield for biopsy diagnosis.