title: Improving accuracy in image-guided prostate biopsy by using trocar-sharpened needles.
abstract: OBJECTIVE
  To optimize image-guided prostate biopsy by minimizing the target error with trocar-sharpened needle tips instead of beveled needles, which constantly deviate away from the bevel.
  
  
  METHODS
  We performed stereotactic biopsies on two prostate phantoms, which incorporate three randomly placed TRUS-visible lesions. Four stereotactic biopsies per lesion were taken under live-ultrasound guidance through a template: two biopsies with conventional beveled needles and two biopsies with novel trocar-sharpened needles. The procedural targeting error (PTE) between the virtually planned biopsy trajectory and the manually registered 3D needle position of every single biopsy core taken was calculated.
  
  
  RESULTS
  The absolute overall targeting error using the novel needle-tip design was 0.13 mm (SD: ± 0.15 mm) with the highest PTE in the sagittal plane (0.18 ± 0.16 mm), followed by the coronal (0.13 ± 0.17 mm) and axial (0.09 ± 0.05 mm) planes. Comparing the PTE of the novel trocar-shaped needles with conventional beveled needles, there was a statistically significant difference in the axial plane [p (overall) = 0.47, p(axial) = 0.03].
  
  
  CONCLUSIONS
  The targeting error of stereotactic biopsies using trocar-sharpened needles is significantly lower than the targeting error of classical beveled needles. Thus, trocar-tip configurations improve the accuracy of computer-assisted biopsies and allow precise assessment of suspicious lesions in the prostate and in other organs accessible to image-guided biopsy.
authors.affiliation: Department of Urology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Timur H
authors.initials: TH
authors.lastname: Kuru
authors.forename: Tobias
authors.initials: T
authors.lastname: Simpfendörfer
authors.forename: Matthias
authors.initials: M
authors.lastname: Roethke
authors.forename: Markus
authors.initials: M
authors.lastname: Hohenfellner
authors.forename: Boris A
authors.initials: BA
authors.lastname: Hadaschik
mesh_terms: D001707:Biopsy, Needle / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D061705:Image-Guided Biopsy / Q000295:instrumentation* / Q000379:methods*; D021621:Imaging, Three-Dimensional; D008297:Male; D009339:Needles; D019047:Phantoms, Imaging; D011467:Prostate / Q000000981:diagnostic imaging / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000473:pathology; D015203:Reproducibility of Results; D014463:Ultrasonography