Effects of urethrography on prostate position: considerations for radiotherapy treatment planning of prostate carcinoma

Shawn Malone, Remco Donker, Mark Broader, Simone Dahrouge, Janos Szanto, Lee Gerig, Greg Bociek, Juanita Crook

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

Purpose: Retrograde urethrography is commonly used to define the prostate apex at simulation. This study evaluated the hypothesis that urethrography causes prostate displacement, resulting in an error in treatment planning.Methods and Materials: Forty-five patients with carcinoma of the prostate were evaluated. Gold seeds were placed in the apex, posterior wall, and base of the gland. In the first 20 patients, the position of the seed-defined apex was compared at simulation (with urethrogram) and on day 1 of treatment (without urethrogram). In the second cohort of 25 patients, the effects of urethrography on prostate position were evaluated directly at simulation by comparing the position of apex pre- and post-urethrography. An analysis was performed to estimate the possible impact of urethrogram-induced prostate motion on target coverage.Results: The mean superior displacement in the first and second cohort was 5.2 mm and 6.8 mm, respectively (combined mean shift 6.1 mm). With a 10-mm field margin below the tip of the urethrogram cone, 56% of patients in this study would have inadequate planning target volume (PTV) coverage.Conclusion: Retrograde urethrography causes a significant superior shift of the prostate. Strict reliance on urethrography in determining the inferior field margin could result in inadequate treatment.

Original languageEnglish (US)
Pages (from-to)89-93
Number of pages5
JournalInternational Journal of Radiation Oncology Biology Physics
Volume46
Issue number1
DOIs
StatePublished - Jan 1 2000

Keywords

  • Conformal radiotherapy
  • Fiducial markers
  • Prostate apex
  • Prostate fiducials
  • Urethrogram

ASJC Scopus subject areas

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

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