title: Optimization of coded aperture radioscintigraphy for sentinel lymph node mapping.
abstract: OBJECTIVE
  Radioscintigraphic imaging during sentinel lymph node (SLN) mapping could potentially improve localization; however, parallel-hole collimators have certain limitations. In this study, we explored the use of coded aperture (CA) collimators.
  
  
  METHODS
  Equations were derived for the six major dependent variables of CA collimators (i.e., masks) as a function of the ten major independent variables, and an optimized mask was fabricated. After validation, dual-modality CA and near-infrared (NIR) fluorescence SLN mapping were performed in pigs.
  
  
  RESULTS
  Mask optimization required the judicious balance of competing dependent variables, resulting in sensitivity of 0.35%, XY resolution of 2.0 mm, and Z resolution of 4.2 mm at an 11.5-cm field of view. The findings in pigs suggested that NIR fluorescence imaging and CA radioscintigraphy could be complementary, but present difficult technical challenges.
  
  
  CONCLUSIONS
  This study lays the foundation for using CA collimation for SLN mapping, and also exposes several problems that require further investigation.
authors.affiliation: Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Fujii
authors.forename: John D
authors.initials: JD
authors.lastname: Idoine
authors.forename: Sylvain
authors.initials: S
authors.lastname: Gioux
authors.forename: Roberto
authors.initials: R
authors.lastname: Accorsi
authors.forename: David R
authors.initials: DR
authors.lastname: Slochower
authors.forename: Richard C
authors.initials: RC
authors.lastname: Lanza
authors.forename: John V
authors.initials: JV
authors.lastname: Frangioni
mesh_terms: D000818:Animals; D005453:Fluorescence; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology*; D051379:Mice; D011877:Radionuclide Imaging / Q000295:instrumentation*; D015203:Reproducibility of Results; D021701:Sentinel Lymph Node Biopsy / Q000295:instrumentation*; D019265:Spectroscopy, Near-Infrared; D034421:Sus scrofa