title: A compact mechatronic system for 3D ultrasound guided prostate interventions.
abstract: OBJECTIVE
  Ultrasound imaging has improved the treatment of prostate cancer by producing increasingly higher quality images and influencing sophisticated targeting procedures for the insertion of radioactive seeds during brachytherapy. However, it is critical that the needles be placed accurately within the prostate to deliver the therapy to the planned location and avoid complications of damaging surrounding tissues.
  
  
  METHODS
  The authors have developed a compact mechatronic system, as well as an effective method for guiding and controlling the insertion of transperineal needles into the prostate. This system has been designed to allow guidance of a needle obliquely in 3D space into the prostate, thereby reducing pubic arch interference. The choice of needle trajectory and location in the prostate can be adjusted manually or with computer control.
  
  
  RESULTS
  To validate the system, a series of experiments were performed on phantoms. The 3D scan of the string phantom produced minimal geometric error, which was less than 0.4 mm. Needle guidance accuracy tests in agar prostate phantoms showed that the mean error of bead placement was less then 1.6 mm along parallel needle paths that were within 1.2 mm of the intended target and 1 degree from the preplanned trajectory. At oblique angles of up to 15 degrees relative to the probe axis, beads were placed to within 3.0 mm along a trajectory that were within 2.0 mm of the target with an angular error less than 2 degrees.
  
  
  CONCLUSIONS
  By combining 3D TRUS imaging system to a needle tracking linkage, this system should improve the physician's ability to target and accurately guide a needle to selected targets without the need for the computer to directly manipulate and insert the needle. This would be beneficial as the physician has complete control of the system and can safely maneuver the needle guide around obstacles such as previously placed needles.
authors: Robarts Research Institute, 100 Perth Drive, London, Ontario N6A 5K8, Canada. jbax@imaging.robarts.ca
authors: Jeffrey
authors: J
authors: Bax
authors: David
authors: D
authors: Smith
authors: Laura
authors: L
authors: Bartha
authors: Jacques
authors: J
authors: Montreuil
authors: Shi
authors: S
authors: Sherebrin
authors: Lori
authors: L
authors: Gardi
authors: Chandima
authors: C
authors: Edirisinghe
authors: Aaron
authors: A
authors: Fenster
mesh_terms: D000362:Agar; D002138:Calibration; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation*; D008297:Male; D019047:Phantoms, Imaging; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D011881:Radiotherapy, Computer-Assisted / Q000295:instrumentation*; D012984:Software; D014463:Ultrasonography
chemical_list: D000362:Agar