Prostate Postbrachytherapy Seed Distribution: Comparison of High-Resolution, Contrast-Enhanced, T1- and T2-Weighted Endorectal Magnetic Resonance Imaging Versus Computed Tomography: Initial Experience

B. Nicolas Bloch, Robert E. Lenkinski, Thomas H. Helbich, Long Ngo, Renee Oismueller, Silvia Jaromi, Klaus Kubin, Robert Hawliczek, Irving D. Kaplan, Neil M. Rofsky

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

Purpose: To compare contrast-enhanced, T1-weighted, three-dimensional magnetic resonance imaging (CEMR) and T2-weighted magnetic resonance imaging (T2MR) with computed tomography (CT) for prostate brachytherapy seed location for dosimetric calculations. Methods and Materials: Postbrachytherapy prostate MRI was performed on a 1.5 Tesla unit with combined surface and endorectal coils in 13 patients. Both CEMR and T2MR used a section thickness of 3 mm. Spiral CT used a section thickness of 5 mm with a pitch factor of 1.5. All images were obtained in the transverse plane. Two readers using CT and MR imaging assessed brachytherapy seed distribution independently. The dependency of data read by both readers for a specific subject was assessed with a linear mixed effects model. Results: The mean percentage (± standard deviation) values of the readers for seed detection and location are presented. Of 1205 implanted seeds, CEMR, T2MR, and CT detected 91.5% ± 4.8%, 78.5% ± 8.5%, and 96.1% ± 2.3%, respectively, with 11.8% ± 4.5%, 8.5% ± 3.5%, 1.9% ± 1.0% extracapsular, respectively. Assignment to periprostatic structures was not possible with CT. Periprostatic seed assignments for CEMR and T2MR, respectively, were as follows: neurovascular bundle, 3.5% ± 1.6% and 2.1% ± 0.9%; seminal vesicles, 0.9% ± 1.8% and 0.3% ± 0.7%; periurethral, 7.1% ± 3.3% and 5.8% ± 2.9%; penile bulb, 0.6% ± 0.8% and 0.3% ± 0.6%; Denonvillier's Fascia/rectal wall, 0.5% ± 0.6% and 0%; and urinary bladder, 0.1% ± 0.3% and 0%. Data dependency analysis showed statistical significance for the type of imaging but not for reader identification. Conclusion: Both enumeration and localization of implanted seeds are readily accomplished with CEMR. Calculations with MRI dosimetry do not require CT data. Dose determinations to specific extracapsular sites can be obtained with MRI but not with CT.

Original languageEnglish (US)
Pages (from-to)70-78
Number of pages9
JournalInternational Journal of Radiation Oncology Biology Physics
Volume69
Issue number1
DOIs
StatePublished - Sep 1 2007

Keywords

  • Brachytherapy
  • CT
  • MRI
  • PDA
  • Prostate cancer
  • Seed dislocation

ASJC Scopus subject areas

  • Radiation
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research

Fingerprint Dive into the research topics of 'Prostate Postbrachytherapy Seed Distribution: Comparison of High-Resolution, Contrast-Enhanced, T1- and T2-Weighted Endorectal Magnetic Resonance Imaging Versus Computed Tomography: Initial Experience'. Together they form a unique fingerprint.

  • Cite this