title: Ventilation-perfusion SPECT with 99mTc-DTPA versus Technegas: a head-to-head study in obstructive and nonobstructive disease.
abstract: Lung scintigraphy is primarily used to diagnose pulmonary embolism. Ventilation imaging is often performed using (99m)Tc-DTPA or Technegas, an ultrafine dispersion of (99m)Tc-labeled carbon. Despite the common use of these radioaerosols, they have not been compared in an intraindividual study, and not with ventilation-perfusion (V/P) SPECT. The aim of the present head-to-head study was to systematically investigate differences in ventilation studies performed with (99m)Tc-diethylenetriaminepentaacetate (DTPA) and Technegas.
  
  
  METHODS
  Sixty-three patients, 28 without and 35 with obstructive lung disease, were examined with V/P SPECT using both (99m)Tc-DTPA and Technegas. V/P SPECT images were randomized and assessed independently by 2 masked physicians according to a predefined scoring system. A paired comparison was performed using the Wilcoxon signed-rank test.
  
  
  RESULTS
  In both obstructive and nonobstructive disease, the overall unevenness of radiotracer deposition and the degree of central deposition were more pronounced in (99m)Tc-DTPA than Technegas studies. Because of better peripheral penetration, the extent of reverse mismatch was less when Technegas was used. Additionally, in obstructive disease, the degree of focal deposition in distal airways was more pronounced with (99m)Tc-DTPA. Mismatched perfusion defects were more frequently found with Technegas in obstructive disease.
  
  
  CONCLUSIONS
  This intraindividual comparative study shows that Technegas is the preferred radioaerosol, particularly in obstructive disease.
authors.affiliation: Department of Clinical Physiology, Lund University and Skåne University Hospital, Lund, Sweden. jonas.jogi@med.lu.se
authors.forename: Jonas
authors.initials: J
authors.lastname: Jögi
authors.forename: Björn
authors.initials: B
authors.lastname: Jonson
authors.forename: Marie
authors.initials: M
authors.lastname: Ekberg
authors.forename: Marika
authors.initials: M
authors.lastname: Bajc
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008168:Lung / Q000000981:diagnostic imaging / Q000378:metabolism; D008171:Lung Diseases / Q000000981:diagnostic imaging*; D008173:Lung Diseases, Obstructive / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D013670:Sodium Pertechnetate Tc 99m / Q000493:pharmacokinetics; D016284:Technetium Tc 99m Pentetate / Q000493:pharmacokinetics; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D019275:Radiopharmaceuticals; C056708:Technegas; D013670:Sodium Pertechnetate Tc 99m; D016284:Technetium Tc 99m Pentetate