title: Technique for implantation of fiducial markers in the prostate.
abstract: OBJECTIVE
  To describe our experience in developing a technique for implanting fiducial markers (gold markers and electromagnetic transponders) in the prostate by the transrectal approach under ultrasound guidance.
  
  
  METHODS
  Our technique requires an endocavitary probe (ultrasound transducer) designed for prostate imaging, an ultrasound system with software to visualize the biopsy trajectory on the imaging screen, and a needle guide specifically designed to fit the probe. Critical aspects of the technique include identifying appropriate implantation locations in the gland, correctly orienting the bevel of the implantation needles, ensuring that the bevel is completely within the gland before deploying markers, and achieving adequate spacing of the markers.
  
  
  RESULTS
  Since 1999 we have successfully implanted gold markers in 705 patients. Only 1 patient has developed a urinary tract infection requiring additional antibiotic therapy. There have been no instances of severe rectal bleeding or gross hematuria requiring further intervention. Complication rates have been similarly low for electromagnetic transponders implanted in 44 patients.
  
  
  CONCLUSIONS
  Implantation of fiducial markers is being used to achieve greater accuracy of external beam radiation therapy for prostate cancer. Our experience can serve as a guide to clinicians for performing this increasingly important procedure in an effective and problem-free manner.
authors.affiliation: Department of Urology, University of California San Francisco and UCSF/Mt. Zion Comprehensive Cancer Center, San Francisco, California 94143-0711, USA. katsutoshinohara@hotmail.com
authors.forename: Katsuto
authors.initials: K
authors.lastname: Shinohara
authors.forename: Mack
authors.initials: M
authors.lastname: Roach
mesh_terms: D001707:Biopsy, Needle; D055590:Electromagnetic Phenomena; D004867:Equipment Design; D006046:Gold; D006801:Humans; D008297:Male; D011467:Prostate / Q000000981:diagnostic imaging*; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy*; D019736:Prostheses and Implants; D019919:Prosthesis Implantation / Q000379:methods*; D011878:Radiotherapy / Q000295:instrumentation / Q000379:methods; D014463:Ultrasonography
chemical_list: D006046:Gold