The Importance of SPECT Imaging Attenuation Correction During Treatment Planning for ⁹⁰Y-labeled Glass Microspheres Liver Radioembolization

Nowadays, liver radioembolization with ⁹⁰Y microscpheres represents an innovative treatment for unresectable hepatic tumors. ⁹⁰Y radioembolization treatment planning is performed by means of ^99mTc-MAA SPECT imaging. However, photons interaction within human tissues and, in particular, ^99mTc \(\gamma \)-rays attenuation, may significantly compromise the quantitative accuracy of SPECT images. The aim of this study was to validate a patient-specific and Computed Tomography (CT)-based attenuation correction of SPECT images, by employing and analyzing, both phantom models and clinical liver SPECT images. The results observed suggested that the implementation of attenuation corrections, during the iterative process of SPECT images reconstruction, resulted in qualitatively and quantitatively visually improved images, with higher contrast and increased count density profiles. Moreover, as compared to uncorrected images, attenuation corrected SPECT images presented a counts distribution more proportional to the real radiopharmaceutical concentration, both in phantom model and in human liver. Thus, the methodology implemented will permit to improve the liver radioembolization treatment planning, based on ^99mTc-MAA SPECT imaging and its efficacy, while minimizing the complications.