Scatter correction based on an artificial neural network for 99mTc and 123I dual-isotope SPECT in myocardial and...

The aim of this study was to elucidate the clinical usefulness of scatter correction with an artificial neural network (ANN) in 99mTc and 123I dual-isotope SPECT.

Two algorithms for ANN scatter correction were tested: ANN-10 and ANN-3 employing 10 and 3 energy windows for data acquisition, respectively. Three patients underwent myocardial or brain SPECT with one of the following combinations of radiopharmaceuticals administered: 99mTc-tetrofosmin and 123I-metaiodobenzylguanidine (MIBG), 99mTc-methoxyisobutylisonitrile (MIBI) and 123I-beta-methyl-paraiodophenyl-pentadecanoic acid (BMIPP), or 99mTc-ethyl-cistainate dimmer (ECD) and 123I-iomazenil. The patients were also referred for single-isotope imaging incorporating conventional triple-energy window (TEW) scatter correction. Crosstalk- and scatter-corrected 99mTc- and 123I-SPECT images in dual-isotope acquisition with ANN were compared with those in single-isotope acquisition.

The ANN method well separated 123I and 99mTc primary photons. Although ANN-10 yielded images of poor quality, ANN-3 offered comparable image quality with the single-isotope scan without significant increase of acquisition time.

The proposed method is clinically useful because it provides various combinations of information without anatomical misregistration with one acquisition.