| Title | Correlation of Technetium-99m Macroaggregated Albumin and Yttrium-90 Glass Microsphere Biodistribution in Hepatocellular Carcinoma: A Retrospective Review of Pretreatment Single Photon Emission CT and Posttreatment Positron Emission Tomography/CT. |
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| Authors | Haste, P.; Tann, M.; Persohn, S.; LaRoche, T.; Aaron, V.; Mauxion, T.; Chauhan, N.; Dreher, M.R.; Johnson, M.S. |
| Journal | J Vasc Interv Radiol |
| DOI | 10.1016/j.jvir.2016.12.1221 |
| Abstract |
PURPOSE: To evaluate whether technetium-99 ((99m)Tc)-labeled macroaggregated albumin (MAA) can predict subsequent yttrium-90 ((90)Y) distribution and imaging response in patients with hepatocellular carcinoma (HCC). MATERIALS: Retrospective review was performed of records of 83 patients with HCC who underwent (90)Y glass microsphere radioembolization with (99m)Tc-MAA single photon emission computed tomography (SPECT) and (90)Y positron emission tomography (PET)/CT between January 2013 and December 2014. Images were fused to segment the whole liver normal tissue (WLNT) and the largest tumors. Fused images were reviewed and analyzed for comparison of absorbed dose (AD) to tumors and WLNT as calculated from (99m)Tc-MAA SPECT and from (90)Y PET/CT, subjective imaging comparison of (99m)Tc-MAA SPECT and (90)Y PET for tumors and WLNT, and correlation of tumoral AD with response on follow-up CT. RESULTS: Final analysis included 73 and 63 patients for WLNT and tumor (99m)Tc-MAA/(90)Y correlation, respectively, and 62 patients for AD vs response. (99m)Tc-MAA/(90)Y limit of agreement for each reviewer was viewed as clinically acceptable only for WLNT (-15 to 15 Gy). AD interreviewer variability was clinically acceptable for WLNT but was too broad for tumor. Mean tumor AD for objective response (78%) was 313 Gy vs 234 Gy for nonresponders. No threshold was found between tumor AD and response (P > .1). Catheter mismatch between (99m)Tc-MAA and (90)Y had a direct impact on AD mismatch between the 2 image sets. CONCLUSIONS: (99m)Tc-MAA was found to be a poor surrogate to quantitatively predict subsequent (90)Y AD to hepatocellular tumors. (99m)Tc-MAA distribution correlated with (90)Y distribution in the normal hepatic parenchyma. |
See more Yttrium products. Yttrium (atomic symbol: Y, atomic number: 39) is a Block D, Group 3, Period 5 element with an atomic weight of 88.90585. 
The number of electrons in each of yttrium's shells is [2, 8, 18, 9, 2] and its electron configuration is [Kr] 4d1 5s2. The yttrium atom has a radius of 180 pm and a Van der Waals radius of 219 pm. Yttrium was discovered by Johann Gadolin in 1794 and first isolated by Carl Gustav Mosander in 1840. In its elemental form, Yttrium has a silvery white metallic appearance. Yttrium has the highest thermodynamic affinity for oxygen of any element. 
Yttrium is not found in nature as a free element and is almost always found combined with the lanthanides in rare earth minerals. While not part of the rare earth series, it resembles the heavy rare earths which are sometimes referred to as the "yttrics" for this reason. Another unique characteristic derives from its ability to form crystals with useful properties. The name yttrium originated from a Swedish village near Vaxholm called Yttbery where it was discovered.