59 Comparison between predictive and post-treatment dosimetry for hepatocellular carcinoma patients treated with90Y-glass microsphere radioembolization

Autor: Sébastien Vauclin, Denis Mariano-Goulart, Marilyne Kafrouni, F. Ben Bouallegue, Alina-Diana Ilonca, M. Fourcade
Rok vydání: 2018
Předmět:
Zdroj: Physica Medica. 56:33
ISSN: 1120-1797
Popis: Introduction The aim of this study was to analyze the differences between 99 m Tc-MAA SPECT and 90 Y-microsphere PET dosimetry investigating imaging (spatial resolution, partial volume effect, noise) and clinical factors (catheter positioning, modified vascularization, MAA/microsphere distribution). Methods Nineteen 90 Y-glass microsphere radioembolizations of hepatocellular carcinoma patients were analyzed in this study. For each treatment, predictive and post-treatment doses to tumor and normal liver (NL) were calculated with a dedicated software (PLANET® Dose, DOSIsoft, Cachan, France) applying a convolution method based on voxel-S factors. The mean ( ± standard deviation) administered activity was 3.5 GBq ( ± 1.2) for a mean tumor volume of 546 mL ( ± 408mL). In addition to the tumor average dose ( D avg ) , dose metrics extracted from dose volume histograms were analyzed: minimum dose to 70% and 50% of the tumor volume ( D 70 and D 50 ) and percentage of the tumor volume receiving at least 205 Gy ( V 205 ) , as recommended in the literature for glass-microsphere treatments [1] . Difference and correlation between predictive and post-treatment doses were assessed using a paired Student’s t test and Pearson’s correlation coefficient. Spatial concordance analysis at the voxel level between MAA and microsphere distributions is ongoing. This should provide additional information to better understand the part of dose differences related to clinical factors. Results Dose results showed a good correlation between 99 m Tc-MAA SPECT and 90 Y-microsphere PET based dosimetry (Table 1). However, difference between them was significant for all tumor and NL dose metrics considered. A 90 Y-microsphere PET tendency to underestimate 99 m Tc-MAA SPECT based doses was observed. Preliminary results indicate that the largest dose discrepancies can be explained by clinical differences in terms of administration procedure and particle distribution. Download : Download high-res image (249KB) Download : Download full-size image Conclusions The overall good correlation observed between predictive and post-treatment dosimetry confirm the MAA predictive value. A tendency of 90 Y-microsphere PET to underestimate 99 m Tc-MAA SPECT doses was observed.
Databáze: OpenAIRE
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