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Radioimmunotherapy with radioactive nanoparticles: Biological doses and treatment efficiency for vascularized tumors with or without a central hypoxic area
Author(s) -
Bouchat V.,
Nuttens V. E.,
Michiels C.,
Masereel B.,
Feron O.,
Gallez B.,
Vander Borght T.,
Lucas S.
Publication year - 2010
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3368599
Subject(s) - radioimmunotherapy , radioresistance , dosimetry , nuclear medicine , radiobiology , radiation therapy , radionuclide , cancer research , relative biological effectiveness , monoclonal antibody , radiochemistry , chemistry , radiation , antibody , medicine , physics , immunology , nuclear physics
Purpose: Radioactive atoms attached to monoclonal antibodies are used in radioimmunotherapy to treat cancer while limiting radiation to healthy tissues. One limitation of this method is that only one radioactive atom is linked to each antibody and the deposited dose is often insufficient to eradicate solid and radioresistant tumors. In a previous study, simulations with the Monte Carlo N‐Particle eXtended code showed that physical doses up to 50 Gy can be delivered inside tumors by replacing the single radionuclide by a radioactive nanoparticle of 5 nm diameter containing hundreds of radioactive atoms. However, tumoral and normal tissues are not equally sensitive to radiation, and previous works did not take account the biological effects such as cellular repair processes or the presence of less radiosensitive cells such as hypoxic cells. Methods: The idea is to adapt the linear‐quadratic expression to the tumor model and to determine biological effective doses (BEDs) delivered through and around a tumor. This BED is then incorporated into a Poisson formula to determine the shell control probability (SCP) which predicts the cell cluster‐killing efficiency at different distances “ r ” from the center of the tumor. BED and SCP models are used to analyze the advantages of injecting radioactive nanoparticles instead of a single radionuclide per vector in radioimmunotherapy. Results: Calculations of BED and SCP for different distances r from the center of a solid tumor, using the non‐small‐cell lung cancer as an example, were investigated forY902O 3nanoparticles. With a total activity of about 3.5 and 20 MBq for tumor radii of 0.5 and 1.0 cm, respectively, results show that a very high BED is deposited in the well oxygenated part of the spherical carcinoma. Conclusions: For either small or large solid tumors, BED and SCP calculations highlight the important benefit in replacing the single β ‐emitterY90attached to each antibody by aY902O 3nanoparticle.