A new technique for performing Syed-Neblett template interstitial implants for gynecologic malignancies using transrectal-ultrasound guidance

Purpose: Interstitial brachytherapy plays an important role in the treatment of advanced and recurrent gynecologic malignancies. Unfortunately, the inability to visualize the tumor and surrounding normal structures during the implant has hampered the accuracy and safety of the implant. Transrectal ultrasound guided Syed-Neblett template implantation is a new technique for performing interstitial implants under direct visualization. The details of the technique are presented to demonstrate the ability to accurately guide needle placement into tumor and avoid needle insertion into critical surrounding normal structures. Methods and Materials: The transrectal ultrasound is positioned so that it can visualize the tumor, and normal surrounding structures in both transverse and longitudinal planes. The Syed- Neblett template is positioned and sutured into the perineum. Needles are inserted into the target area under direct visualization through transverse imaging. The bladder and rectum can be directly imaged and thus avoided. Longitudinal imaging is then used to guide the needles to the appropriate depth. In addition, it can be used to assess the length of the target volume and aid in determining the active length of the sources. Results: A total of 12 procedures have been performed on seven patients from August 30, 1995 to April 12, 1996. The presenting diseases included: Stage IIIb cervical cancer in four cases, recurrent endometrial cancer in two cases, and Stage III vaginal cancer in one case. The total length of time for implantation of the needles ranged from 45 to 165 min (median-130 min). Conclusion: Transrectal ultrasound guidance provides real-time visualization of the target volume and normal tissues during interstitial implantation of gynecologic malignancies and allows for accurate needle placement.