title: Intraoperative segmentation of iodine and palladium radioactive sources in C-arm images.
abstract: OBJECTIVE
  Dynamic dosimetry is becoming the standard to evaluate the quality of radioactive implants during brachytherapy. For this, it is essential to obtain a 3D visualization of the implanted seeds and their relative position to the prostate. A method was developed to obtain a robust and precise segmentation of seeds in C-arm images, and this approach was tested using clinical datasets.
  
  
  METHODS
  A region-based implicit active contour approach was used to delineate implanted seeds. Then, a template-based matching was employed to segment iodine implants whereas a K-means algorithm is implemented to resolve palladium seed clusters. To validate the method, 55 C-arm images from 10 patients were used for the segmentation of iodine sources, whereas 225 C-arm images from 16 patients were used for the palladium case.
  
  
  RESULTS
  Compared to manual ground truth segmentation of 6,002 iodine seeds and 15,354 palladium seeds, 98.7 % of iodine sources were automatically detected and declustered showing a false-positive rate of only 1.7 %. A total of 98.7 % of palladium sources were automatically detected and declustered with a false-positive rate of only 2.0 %.
  
  
  CONCLUSIONS
  An automated segmentation method was developed that is able to perform the identification and annotation processes of seeds on par with a human expert. This method was shown to be robust and suitable for integration in the dynamic dosimetry workflow of prostate brachytherapy interventions.
authors: Technical University of Munich, Munich, Germany, filippo@in.tum.de.
authors: Chiara
authors: C
authors: Amat di San Filippo
authors: Gabor
authors: G
authors: Fichtinger
authors: William James
authors: WJ
authors: Morris
authors: Septimiu E
authors: SE
authors: Salcudean
authors: Ehsan
authors: E
authors: Dehghan
authors: Pascal
authors: P
authors: Fallavollita
mesh_terms: D000465:Algorithms; D001918:Brachytherapy / Q000379:methods*; D019160:Endosonography / Q000379:methods; D006801:Humans; D021621:Imaging, Three-Dimensional; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D016343:Monitoring, Intraoperative / Q000379:methods*; D010165:Palladium / Q000627:therapeutic use*; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000532:radiotherapy* / Q000601:surgery; D011829:Radiation Dosage; D011868:Radioisotopes / Q000627:therapeutic use*; D025321:Surgery, Computer-Assisted
chemical_list: D007457:Iodine Radioisotopes; D011868:Radioisotopes; D010165:Palladium