title: Therapeutic usability of two different fiducial gold markers for robotic stereotactic radiosurgery of liver malignancies: A pilot study.
abstract: OBJECTIVE
  To assess how the application of different types of markers affects the tracking accuracy of CyberKnife's.
  
  
  METHODS
  Fifteen patients were recruited and subjected to the ultrasound-guided placement of markers. Two different type of needles 25 gauge (G) and 17 G containing two different fiducial marker, gold notched flexible anchor wire 0.28 mm × 10 mm (25 G needle) and gold cylindrical grain 1 mm × 4 mm (17 G), were used. Seven days after the procedure, a CyberKnife planning computed tomography (CT) for the simulation of radiation treatment was performed on all patients. A binary CT score was assigned to the fiducial markers visualization. Also, the CT number was calculated for each fiducial and the values compared with a specific threshold.
  
  
  RESULTS
  For each patient from 1 to 5, intra-hepatic markers were placed (one in 2 patients, three in 8 patients, four in 3 patients, and five in 2 patients). A total of 48 needles were used (thirty-two 17 G and sixteen 25 G) and 48 gold markers were placed (32 Grain shaped markers and 16 Gold Anchor). The result showed that the CT visualization of the grain markers was better than the anchor markers (P = 5 × 10(-9)). Furthermore, the grain markers were shown to present minor late complications (P = 3 × 10(-6)), and the best CT threshold number (P = 0.0005).
  
  
  CONCLUSIONS
  The study revealed that the Gold Anchor fiducial marker is correlated with a greater number of late minor complications and low visualization by the CT.
authors.affiliation: Maria Marsico, Integrate Activity Department 1, Gastroenterology, AOU Modena University Hospital, 41121 Modena, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Marsico
authors.affiliation: Maria Marsico, Integrate Activity Department 1, Gastroenterology, AOU Modena University Hospital, 41121 Modena, Italy.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Gabbani
authors.affiliation: Maria Marsico, Integrate Activity Department 1, Gastroenterology, AOU Modena University Hospital, 41121 Modena, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Livi
authors.affiliation: Maria Marsico, Integrate Activity Department 1, Gastroenterology, AOU Modena University Hospital, 41121 Modena, Italy.
authors.forename: Maria Rosa
authors.initials: MR
authors.lastname: Biagini
authors.affiliation: Maria Marsico, Integrate Activity Department 1, Gastroenterology, AOU Modena University Hospital, 41121 Modena, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Galli
keywords: CyberKnife; Fiducial markers; Liver malignancies; Radiation therapy; Robotic radiosurgery; Stereotactic radiosurgery