title: Efficacy of high-energy collimator for sentinel node lymphoscintigraphy of early breast cancer patients.
abstract: BACKGROUND
  Lymphoscintigraphy is an important part of sentinel node mapping in breast cancer patients. Sometimes star shaped artefacts due to septal penetration can be problematic during imaging. In the current study, we evaluated the possibility of high energy (HE) collimators use for lymphoscintigraphy.
  
  
  METHODS
  Twenty patients with early breast carcinoma were included. Thirty minutes after radiotracer injection (99mTc-antimony sulphide colloid), anterior and lateral images were acquired using a dual head gamma camera equipped with a parallel hole low energy high resolution (LEHR) collimator on one head and HE collimator on another head. All images were reviewed by two nuclear medicine specialists regarding detectability and number of axillary sentinel nodes and presence of star artefact.
  
  
  RESULTS
  All images taken by LEHR collimators showed star artefact of the injection site. No image taken by HE collimator showed this effect. In two patients the sentinel node was visible only by HE collimator. Tumour location in both of these patients was in the upper lateral quadrant and both had history of excisional biopsy. In two patients additional sentinel node was visible adjacent to the first one only on the LEHR images.
  
  
  CONCLUSIONS
  HE collimators can be used for sentinel lymph node mapping and lymphoscintigraphy of the breast cancer patients. This collimator can almost eliminate star-shaped artefacts due to septal penetration which can be advantageous in some cases. However, to separate two adjacent sentinel nodes from each other LEHR collimators perform better.
authors.affiliation: Nuclear Medicine Research Center, Faculty of Medicine, Imam Reza Hospital, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Kamran
authors.initials: K
authors.lastname: Aryana
authors.forename: Mohaddeseh
authors.initials: M
authors.lastname: Gholizadeh
authors.forename: Mehdi
authors.initials: M
authors.lastname: Momennezhad
authors.forename: Maryam
authors.initials: M
authors.lastname: Naji
authors.forename: Mohsen
authors.initials: M
authors.lastname: Aliakbarian
authors.forename: Mohammad Naser
authors.initials: MN
authors.lastname: Forghani
authors.forename: Ramin
authors.initials: R
authors.lastname: Sadeghi