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Apr 1 – 5, 2019
Fairmont Château Laurier Hotel
UTC timezone

Image-based approach for absorbed dose estimation of 64Cu/225Ac-DOTA-trastuzumab using Monte Carlo simulation

Not scheduled
15m
Fairmont Château Laurier Hotel

Fairmont Château Laurier Hotel

Speaker

Dr Sang-Keun Woo (Korea Institute of Radiological and Medical Sciences)

Description

Purpose: Image-based absorbed dose calculation studies have been performed to evaluate the characteristics of theranostic radiopharmaceuticals. The aim of this study was to evaluate the 64Cu and 225Ac-DOTA-trastuzumab absorbed dose in mice using image-based Monte Carlo simulation. Materials and Methods: 64Cu-DOTA-trastuzumab PET image was acquired at 3 time point at 3, 24, and 48 hour after radiopharmaceuticals injection in mice. Time-integrated activity coefficient in source organs called residence time was calculate in region of interest (ROI) delineable organs. Image-based source organ 64Cu/225Ac S-value were calculate using Geant 4 Monte Carlo simulation. Absorbed dose for 225Ac-DOTA-trastuzumab was calculated by 64Cu-DOTA-trastuzumab residence time and Monte Carlo simulated 225Ac dose map. The relative biological efficiency (RBE) of the alpha particles emitted from 225Ac, was estimated to be 5 (RBE = 5). 225Ac-DOTA-trastuzumab absorbed dose was considered all decay step of 225Ac radioisotopes (221Fr, 217At, 213Bi, 213Po, 209Tl and 209Pb) and summed up after applying weighting factors in the two possible pathways, 2% for 209Tl and 98% for 213Po. Results: Residence time of 64Cu-DOTA-trastuzumav in liver was 1.80 MBq-h/MBq that is high uptake region in normal subject. Liver absorbed dose of 64Cu- and 225Ac DOTA-trastuzumab were 2.73E-02 mGy/MBq, 6.37E+00 SvRBE5/MBq. 64Cu-DOTA-trastuzumab absorbed does in lung, kidney, and spleen were 2.97E-03, 3.86E-04, 3.62E-05 mGy/MBq, respectively. 225Ac-DOTA-trastuzumab absorbed does in lung, kidney, and spleen were 3.10E-01, 9.18E-02, 9.12E-03 SvRBE5/MBq, respectively. 225Ac-DOTA-trastuzumab absorbed dose was 2.34E+02 fold higher than 64Cu-DOTA-trastuzumab. Conclusion: We performed the 64Cu-DOTA-trastuzumab PET imaging and estimated the image-based internal absorbed dose of 225Ac-DOTA-trastuzumab. This result may help to strategy of treatment for HER2-positive cancer patients using targeted alpha therapy of 225Ac radioisotope.
Email Address skwoo@kirams.re.kr
Presentation Type Poster

Primary author

Dr Sang-Keun Woo (Korea Institute of Radiological and Medical Sciences)

Co-authors

Dr Chul-Hee Lee (Department of Nuclear Medicine, Korea Institute of Radiological and Medical Sciences, Seoul, Korea) Dr Hwunjae Lee (Department of Nuclear Medicine, Korea Institute of Radiological and Medical Sciences, Seoul, Korea) Dr Ilhan Lim (Department of Nuclear Medicine, Korea Institute of Radiological and Medical Sciences, Seoul, Korea) Dr Kyo Chul Lee (Division of applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, Korea) Dr Sang Moo Lim (Department of Nuclear Medicine, Korea Institute of Radiological and Medical Sciences, Seoul, Korea) Mr Wook Kim (Division of applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, Korea) Dr Yong Jin Lee (Division of applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, Korea)

Presentation materials

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