Exclusive MRI-based tandem and colpostats reconstruction in gynaecological brachytherapy treatment planning

Radiother Oncol. 2009 May;91(2):181-6. doi: 10.1016/j.radonc.2008.09.004. Epub 2008 Oct 22.

Abstract

Purpose: According to the GYN GEC-ESTRO Recommendations, MRI is needed with the modality of T2 weighted. CT-MR compatible tandem plus colpostats (T/C) (Nucletron) is widely used in cervical brachytherapy. The major challenge of MRI is the lack of dummy catheters. Therefore, an additional imaging modality is usually required. One disadvantage of sliced-based reconstruction is that resolution in longitudinal directions can be affected by the slice thickness. The aim of this study is to present a modified T/C applicator in which the catheter visibility is significantly improved.

Methods and materials: A modification to the existing T/C applicator has been made available, increasing the catheter entrance diameter. It allows a greater dummy catheter diameter, and consequently it can be filled with more material per unit length. Visibility was studied with different materials.

Results: The catheter filled with saline water plus iodine compound was clearly seen in both axial and longitudinal acquisitions. To avoid uncertainties introduced by the slice thickness, a simple procedure is presented using longitudinal acquisitions.

Conclusions: The modified applicator plus catheter allows a powerful signal in T2 weighted MRI, using a very simple and accessible material. Also, a method is proposed to solve the problem of the uncertainty derived from slice thickness using few longitudinal acquisitions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brachytherapy / instrumentation
  • Brachytherapy / methods*
  • Catheterization
  • Female
  • Genital Neoplasms, Female / radiotherapy*
  • Humans
  • Magnetic Resonance Imaging / methods*
  • Radiotherapy Dosage
  • Radiotherapy Planning, Computer-Assisted*