title: Simultaneous dual-isotope imaging based on an artificial neural network for evaluating myocardial perfusion and fatty acid metabolism.
abstract: BACKGROUND
  We contrived a scatter correction method based on an artificial neural network (ANN) and applied it to the simultaneous evaluation of myocardial perfusion and fatty acid metabolism in single-photon emission computed tomography (SPECT).
  
  
  METHODS
  The count data of three energy windows were used as inputs of the ANN. The count ratios of the estimated primary-to-total photons for (99m)Tc and (123)I, which were used to reconstruct (99m)Tc and (123)I images, were calculated using the ANN. In a phantom study, single- and dual-isotope imaging with (99m)Tc/(123)I and (201)Tl/(123)I was performed by means of a cardiac phantom simulating patients with and without obesity. In a human study, five normal volunteers and ten patients with myocardial infarction underwent myocardial perfusion and fatty acid metabolism imaging with single and dual SPECT with combinations of (99m)Tc-methoxyisobutylisonitrile/(123)I-beta-methyl(p-iodophenyl)pentadecanoic acid (BMIPP) and (201)Tl/(123)I-BMIPP as tracers.
  
  
  RESULTS
  Technetium-99m yielded more homogeneous images than (201)Tl because of the lower degree of photon attenuation, especially in the condition of obese patients, resulting in clearer visualization of the perfusion-metabolism mismatch. Dual (99m)Tc/(123)I SPECT offered comparable images with single SPECT in assessing myocardial damage.
  
  
  CONCLUSIONS
  The method effectively separated (99m)Tc and (123)I primary photons and proved applicable to (99m)Tc/(123)I dual-isotope myocardial SPECT.
authors: Department of Radiology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan. junhashi@tokai-u.jp
authors: Jun
authors: J
authors: Hashimoto
authors: Koichi
authors: K
authors: Ogawa
authors: Jingming
authors: J
authors: Bai
authors: Atsushi
authors: A
authors: Kubo
authors: Yutaka
authors: Y
authors: Imai
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005227:Fatty Acids / Q000378:metabolism*; D005260:Female; D006801:Humans; D007462:Iodobenzenes; D008297:Male; D008875:Middle Aged; D009010:Monte Carlo Method; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D016571:Neural Networks, Computer; D019047:Phantoms, Imaging; D017785:Photons; D011857:Radiographic Image Interpretation, Computer-Assisted; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D005227:Fatty Acids; D007462:Iodobenzenes; D019275:Radiopharmaceuticals; C049338:iodofiltic acid; D017256:Technetium Tc 99m Sestamibi