• Ramadan Ali Hassan
• Saud Hamid AL Lehyani
• Banan . Bahuwayrith
• Saeid Al-Qahtan

The aim to study the effects of source concentration, acquisition & processing parameters on DSPECT image quality. The FWHM, differential uniformity, contrast, and SNR in the three transverse slices of the phantom was analyzed. When the phantom was filled with 20 mCi 99m Tc & 0.4 mCi 131I, were FWHM, differential uniformity and contrast are improved (P-values were statistically significant) with the higher SNR. On the other hand, HEGP collimator had better FWHM, differential uniformity and contrast with a suitable SNR. In the case of showed improvement of resolution in the case of 128 views rather than in 32 and 64 views. But in the case of Diff. Unif. % and the contrast we found that 64 NOP has the better values, which indicate the higher image quality. For SNR 32 NOP given the best values. In practice, approximately 60 views are adequate for most clinical studies. The scattering compensation is TEW subtraction method. Also, the study showed that, the reconstruction of DSPECT data were by (OSEM) iterative algorithm demonstrated quantitative accuracy comparable to FBP, FLASH-3D algorithm.

Simultaneous radioisotope, 131I & 99m Tc imaging, Dual Single Photon Emission Computed Tomography (DSPECT), Imaging factors, image quality.

"Evaluation of Simultaneous Dual-radioisotope SPECT Imaging Using 99m Tc and 131I", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.9, Issue 4, page no.d709-d729, April-2022, Available :http://www.jetir.org/papers/JETIR2204385.pdf

"Evaluation of Simultaneous Dual-radioisotope SPECT Imaging Using 99m Tc and 131I", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.9, Issue 4, page no. ppd709-d729, April-2022, Available at : http://www.jetir.org/papers/JETIR2204385.pdf