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Updated: Jul 7, 2026
Use of MRI-ultrasound Fusion to Achieve Targeted Prostate Biopsy
Published on: April 9, 2019
Technique for implantation of fiducial markers in the prostate
Katsuto Shinohara1, Mack Roach
1Department of Urology, University of California San Francisco and UCSF/Mt. Zion Comprehensive Cancer Center, San Francisco, California 94143-0711, USA. katsutoshinohara@hotmail.com
Objectives:
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.
