Program Information
Comparison of Uptake Distribution Between Yttrium-90 SPECT/CT and Pretreatment Technetium-99m-Macroaggregated Albumin (99mTc-MAA) SPECT/CT in Selective Internal Radiation Therapy
SA Debebe1*, J Franquiz2 , A McGoron3 , (1) Florida International University (FIU), Miami, FL, (2) Radiological Physics of South Florida, Miami, Florida, Miami, Florida, (3) Florida International University, Miami, Florida
Presentations
TU-C3-GePD-IT-1 (Tuesday, August 1, 2017) 10:30 AM - 11:00 AM Room: Imaging ePoster Theater
Purpose: The aim of this study is to apply quantitative image improvement on yttrium-90 (90Y) single-photon emission computed tomography (SPECT) images after Selective Internal Radiation Therapy (SIRT) to be able to quantitatively compare uptake distribution with pretherapeutic Technetium-99m-macroaggregated albumin (99mTc-MAA) SPECT images.
Methods: SPECT/CT data of patients who underwent SIRT for primary or metastatic liver cancer were acquired. 99mTc-MAA SPECT/CT scans were collected for the corresponding patients. A Jasczak phantom with eight spherical inserts of various sizes was used to obtain optimal iteration number of the spatial resolution recovery algorithm for improving the quality of 90Y SPECT images. Calibration factors (CF) for activity estimation were generated from the 90Y SPECT images. Tumor areas were segmented using an active contour method. Finally, comparison of uptakes on 99mTc-MAA and 90Y SPECT images were assessed using tumor to healthy liver ratios (TLRs). The 99mTc-MAA and 90Y SPECT images were registered for correlation analysis.
Results: We were able to achieve improvement in contrast to noise ratio as well as contrast recovery coefficients on patient and phantom 90Y SPECT images respectively after spatial resolution recovery. Total activity estimation in liver gave mean percent error of -4 ± 12 (mean ± std, range -30 to +14) for patients using CF generated from liver segment only. Activity estimation in the spherical inserts of the phantom gave mean percent error of -23 ± 41. Total mean TLR was 7.20 ± 7.82 and 5.05 ± 1.79 on 99mTc-MAA and 90Y SPECT respectively. Result of the regression analysis of the mean TLRs between 99mTc-MAA and 90Y SPECT images exhibited a significant correlation (r=0.77, p<0.05).
Conclusion: This study demonstrates that significant correlation can be obtained between pretherapeutic 99mTc-MAA and posttherapeutic 90Y SPECT mean TLR after post reconstruction image improvement on 90Y SPECT images.
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