Use of needle track detection to quantify the displacement of stranded seeds following prostate brachytherapy

Julio R. Lobo, Mehdi Moradi, Nick Chng, Ehsan Dehghan, William J. Morris, Gabor Fichtinger, Septimiu E. Salcudean

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


We aim to compute the movement of permanent stranded implant brachytherapy radioactive sources (seeds) in the prostate from the planned seed distribution to the intraoperative fluoroscopic distribution, and then to the postimplant computed tomography (CT) distribution. We present a novel approach to matching the seeds in these distributions to the plan by grouping the seeds into needle tracks. First, we identify the implantation axis using a sample consensus algorithm. Then, we use a network flow algorithm to group seeds into their needle tracks. Finally, we match the needles from the three stages using both their transverse plane location and the number of seeds per needle. We validated our approach on eight clinical prostate brachytherapy cases, having a total of 871 brachytherapy seeds distributed in 193 needles. For the intraoperative and postimplant data, 99.31% and 99.41% of the seeds were correctly assigned, respectively. For both the preplan to fluoroscopic and fluoroscopic to CT registrations, 100% of the needles were correctly matched. We show that there is an average intraoperative seed displacement of 4.94 ± 2.42 mm and a further 2.97 ± 1.81 mm of postimplant movement. This information reveals several directional trends and can be used for quality control, treatment planning, and intraoperative dosimetry that fuses ultrasound and fluoroscopy.

Original languageEnglish (US)
Article number6095633
Pages (from-to)738-748
Number of pages11
JournalIEEE Transactions on Medical Imaging
Issue number3
StatePublished - Mar 2012
Externally publishedYes


  • Computed-tomography (CT)
  • minimum cost network flow
  • prostate brachytherapy
  • X-ray fluoroscopy

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Computer Science Applications
  • Radiological and Ultrasound Technology
  • Software


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