Interfraction prostate displacement during image-guided radiotherapy using intraprostatic fiducial markers and a cone-beam computed tomography system: A volumetric off-line analysis in relation to the variations of rectal and bladder volumes

Gianluca Ingrosso, Roberto Miceli, Elisabetta Ponti, Andrea Lancia, Daniela Di Cristino, Francesco De Pasquale, Pierluigi Bove, Riccardo Santoni

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: Prostate motion during the radiotherapy course is an important issue. This study investigated the inter-fraction prostate motion in controlled rectal filling condition. Methods: 10 prostate cancer patients underwent image-guided radiotherapy (IGRT) using a cone-beam computed tomography (CBCT) system, after the insertion of fiducial markers (FMs). The planning CT was the reference CT (CTref) used to estimate the reference intermarker distances, and CBCTs were used for off-line comparison with CTref. We evaluated the influence of rectal and bladder volume on prostate shifts. We calculated the required planning target volume (PTV) margins in this patient population. Results: 120 CBCTs were analyzed. Mean prostate displacements (± SD) along the 3 axes (x, y, z) averaged over the 10 patients, were: 0.90 ± 0.84 mm in x, 0.00 ± 2.07 mm in y, -0.80 ± 1.28 mm in z. There is a statistically significant anti-correlation between prostate displacements and: bladder volume variations (P < 0.001) in the y-axis, and rectal volume variations (P < 0.05) in the z-axis. PTV margins obtained for the directions x, y and z are respectively 2.5, 5.6 and 3.9 mm. Conclusion: IGRT in reproducible empty rectum condition allow a high reduction of daily treatment uncertainties.

Original languageEnglish
Pages (from-to)S69-S75
JournalJournal of Cancer Research and Therapeutics
Volume15
Issue number8
DOIs
Publication statusPublished - Mar 1 2019

Keywords

  • Image-guided radiotherapy
  • inter-fraction displacement
  • prostate cancer
  • volumetric off-line analysis

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging

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