1. Liver Dose Deposition (mGy)
Optimization of Image-based Dosimetry in Y90 Radioembolization: a Monte Carlo approach using the GATE simulation toolkit
K. Mountris1, A. Autret2, P. Papadimitroulas1, G. Loudos3, D. Visvikis2, G. Nikiforidis1
1 Department of Medical Physics, School of Medicine, University of Patras, Rion, GR , 2 LaTIM, UMR 1101 INSERM, CHRU Brest, Brest, France
3 Department of Biomedical Engineering, Technological Educational institute of Athens, Ag. Spyridonos Street, Egaleo GR , Athens, Greece
Introduction: Y90 Radioembolization is a selective internal radiation therapy based on the heterogeneous distribution of Y90 microspheres in the target area through the hepatic artery, exploiting the unique blood flow of the human liver.
Purpose: The improvement of the pretreatment image-based (IB) dosimetry using as imaging surrogate macroaggregated albumin (MAA) labeled with Ga68 or Cu64 instead of Tc99m was investigated according to the correlation with the follow up image-based dosimetric results of Y90 microspheres PET acquisition , using Monte Carlo (MC) simulations.
Methods:
Results:
Divergence
(%)
Tc99m-MAA
Ga68-MAA
Cu64-MAA
IB tumor dose
+1.58%
-2.61%
-0.36%
IB liver dose
+12.77%
+4.26%
+3.29%
XCAT phantom generation with tumor of kg
MC simulations with GATE open source toolkit
Y90 IB tumor dose: Gy
Y90 IB liver dose: Gy
52.31 mGy liver dose deposition
from 200 MBq Tc99m-MAA
Liver Dose Deposition (mGy)
Tc99m-MAA
Ga68-MAA
Cu64-MAA
52.31
33.35
66.01
OPL-EM / ML-EM reconstruction
Y90 kernel convolution
MC estimation of imaging surrogates’ dose deposition in liver
36.2 % decrease in dose for 100 MBq
of Ga68-MAA
26.2 % increase in dose for 100 MBq
of Cu64-MAA
Conclusions:
Ability to simulate PET-based follow up dosimetry exploiting the tiny branch of positron emission of Y90.
Improvement in correlation with the pre-treatment planning using PET imaging surrogates.
Ga68-MAA showed dosimetric improvement and decrease in dose deposition supports further research.
The radiochemical stability of Cu64-MAA has to be investigated due to it’s appealing dosimetric results.
References:
Konstantinos Mountris et al. “Liver Radioembolization with microspheres Y90: Method Investigation and dosimetry improvement using Monte Carlo Simulations”, Master Thesis University of Patras, Greece.