TY - JOUR T1 - Novel modification of reconstruction algorithm for better image quality of post PRRT and post SIRT 90-Yttrium PET scan JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 2024 LP - 2024 VL - 60 IS - supplement 1 AU - Gabriel Lim AU - Lenith Cheng AU - Xuexian Yan Y1 - 2019/05/01 UR - http://jnm.snmjournals.org/content/60/supplement_1/2024.abstract N2 - 2024Introduction: Yttrium-90 is a therapeutical radionuclide which is used in both peptide receptor radionuclide therapy (PRRT) for neuroendocrine tumors and selective intra-arterial radionuclide therapy (SIRT) for liver tumors. That it has no gamma emission significantly limits post-therapy imaging and direct dosimetry. Other than Bremsstrahlung imaging which bears inherent flaw of poor resolution, PET scan has been tried for post-therapy localization anddosimetry purposes. However, in daily clinical practice, its use has been hampered by its extremely low abundance of internal pair production that translates into prolonged scan time and relatively poor diagnostic image quality. We aim to improve image quality by optimizing the reconstruction algorithm without increasing patient dose or prolonging scan acquisition time, minimizing patient discomfort. Subjects and methods: 4 consecutive patients with neuroendocrine tumors treated with 90Y-PRRT and 6 consecutive patients with liver tumors treated with 90Y-PRRT were enrolled in the study. Administered patient dose ranged from 2.2 GBq-4.4 GBq for PRRT and 1 GBq-3 GBq for 90Y-SIRT. Post PRRT and SIRT, all patients were scanned of the region of interest for 1 bed position for 30 minutes using a GE 690 Discovery PET/CT scanner. Acquired data were reconstructed with 2 traditionally used algorithms (A, B) in our center and a purposely modified algorithm (namely LKYG) respectively. The resulting images were presented to 10 blinded, experienced nuclear medicine physicians for semi-quantitative scoring of image quality. Scores of each reconstruction algorithm on 10 scans by 10 readers were analyzed using ANOVA and t-test. Results: Reconstruction algorithm LKYG, featured by dramatic reduction of number of iterations, thinning out of the filter Cutoff, and increase of number of subsets in comparison with other routinely used algorithms, significantly improved the quality of 90Y PET scan, in all post-PRRT and post-SIRT patients. Conclusion: A modified reconstruction algorithm for 90Y PET imaging significantly enhances the image quality without an increase in scan acquisition time or a decrease in patient comfort, resulting in superior tumor delineation and accuracy of dosimetry. Based on our experience in multiple patients, we recommend this reconstruction algorithm for routine clinical use in Y-90 PET imaging. Keywords: PET, Yttrium-90, PRRT, SIRT, neuroendocrine tumor, hepatocellular carcinoma, liver metastases View this table: ER -