title: The impact of radiopharmaceutical particle size on the visualization and identification of sentinel nodes in breast cancer.
abstract: OBJECTIVE
  The aim of this study was to compare the success rate in lymphatic mapping and sentinel node biopsy in breast cancer using two radiopharmaceuticals.
  
  
  METHODS
  The study included 119 breast cancer patients who underwent lymphoscintigraphy after a single intratumoral injection of 99mTc-labelled human albumin colloid with a particle size of 0.2-3 microm (Albu-Res) (large particle group) and 119 pair-matched control patients who underwent lymphoscintigraphy using 99mTc-labelled albumin colloid with a particle size of < 80 nm (Nanocoll) (small particle group). The dose of the tracer was used as the matching factor.
  
  
  RESULTS
  Lymphoscintigraphy showed sentinel nodes in the axilla in 101 patients (85%) in the large particle group and in 104 patients (87%) in the small particle group. The mean number of visualized nodes in the axilla was 1.7 in the small particle group and 1.3 in the large particle group (P < 0.05). No radioactive nodes were found in the axilla during the operation in 22 patients (18%) in the small particle group and 11 patients (9%) in the large particle group (P < 0.06). Patients who avoided axillary clearance had a similar number of harvested radioactive nodes irrespective of the particle size of the tracer.
  
  
  CONCLUSIONS
  It can be concluded that the success rate in the identification of axillary sentinel nodes may be higher when using the smaller particles, despite the similar visualization rate in lymphoscintigraphy. The number of harvested radioactive nodes was not affected by the particle size of the tracer in patients who avoided axillary clearance.
authors.affiliation: Breast Surgery Unit, Maria Hospital, Helsinki University Hospital, Helsinki, Finland. marjut.leidenius@hus.fi
authors.forename: Marjut H
authors.initials: MH
authors.lastname: Leidenius
authors.forename: Esa A
authors.initials: EA
authors.lastname: Leppänen
authors.forename: Leena A
authors.initials: LA
authors.lastname: Krogerus
authors.forename: Karl A v
authors.initials: KA
authors.lastname: Smitten
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla / Q000000981:diagnostic imaging* / Q000473:pathology; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D016022:Case-Control Studies; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D010316:Particle Size; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000737:chemistry / Q000145:classification; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*; D013668:Technetium Tc 99m Aggregated Albumin / Q000737:chemistry* / Q000145:classification
chemical_list: D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin