PT - JOURNAL ARTICLE AU - Franklin Wong AU - William Erwin AU - Brian Wong AU - Peter Park AU - Sam Beddar AU - Christopher Crane AU - Eugene Koay TI - Functional liver volume from Tc99m sulfur colloid liver SPECT-CT correlates with outcomes of image-guided radiotherapy of liver in patients with cirrhosis DP - 2016 May 01 TA - Journal of Nuclear Medicine PG - 1400--1400 VI - 57 IP - supplement 2 4099 - http://jnm.snmjournals.org/content/57/supplement_2/1400.short 4100 - http://jnm.snmjournals.org/content/57/supplement_2/1400.full SO - J Nucl Med2016 May 01; 57 AB - 1400Objectives Patients undergoing image-guided radiation therapy (IGRT) of liver malignancies benefit from liver SPECT-CT to identify function liver tissues to avoid excessive irradiation. This is especially important with concurrent liver dysfunction including cirrhosis. This study is to assess whether functional liver volume (FLV) derived before IGRT correlates with clinical outcomes. A secondary objective is to determine the optimal approach to derive FLV from liver SPECT-CT.Methods Under an approved protocol, Tc99m- sulfur colloid (SC) SPECT-CTs from consecutive patients who received liver IGRT were reviewed. SC was chosen as a surrogate of hepatic function because of simplicity of logistics of less stringent timing requirement after injection (as with other hepatic imaging agents such as HIDA). FLV were determined by methods based on SPECT-CT images as as appeared on PACS (FuncLivVol, Liver-TumorVol) and reprocessed methods including intensity gradient edge detection (PETEdge) and relative threshold (Th) at 20% to 50%. Systat 13 plus Exact Tests were used to calculate Pearson P to exclude random association (P>0.05) between FLVs from different methods, mean functional liver absorbed doses, liver volume received less than total dose, Child-Pugh scores and average dose per fraction versus recorded binary data survival, clinical responses and ordinal data of maximum toxicity grades.Results A total of 12 consecutive patient studies were collected; one was excluded because IGRT was not done after SPECT-CT. Exact tests from Systat 13.0 were used for statistical calculations to account for small sample sizes. At significance levels P<0.05, FLV from Th=0.20-0.50 had positive associations (best at 0.40) with clinical response to IGRT but negative associations with maximum toxicity grades (best at 0.43). Trends of naders at 0.4 to 0.43 were observed in the range of relative thresholds for the SPECT-CT.Conclusions Relative thresholds in Tc99m SC SPECT-CT are able to derive FLVs which correlates with clinical outcomes after subsequent IGRT namely, maximum toxicity grades and clinical responses. Correlation with outcome is a valid and practical criterion to optimize Th which may then allow establishing critical FLV values for radiation dose adjustment for better IGRT planning and better patient outcomes.