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Targeted dose enhancement in radiotherapy for breast cancer using gold nanoparticles, part 2: A treatment planning study
Author(s) -
Strigari Lidia,
Ferrero Veronica,
Visonà Giovanni,
Dalmasso Federico,
Gobbato Andrea,
Cerello Piergiorgio,
Visentin Sonja,
Attili Andrea
Publication year - 2017
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 - 10.1002/mp.12178
Subject(s) - radiation therapy , breast cancer , radiation treatment planning , colloidal gold , dosimetry , irradiation , distribution (mathematics) , nuclear medicine , cancer , medicine , nanoparticle , materials science , nanotechnology , physics , mathematics , mathematical analysis , nuclear physics
Purpose In recent years, there has been growing interest in the use of gold nanoparticles (GNPs) combined with radiotherapy to improve tumor control. However, the complex interplay between GNP uptake and dose distribution in realistic clinical treatment are still somewhat unknown. Methods The effects of different concentrations of 2 nm diameter GNP, ranging from 0 to 5 × 10 5nanoparticles per tumoral cell, were theoretically investigated. A parametrization of the GNP distribution outside the target was carried out using a Gaussian standard deviation σ , from a zero value, relative to a selective concentration of GNPs inside the tumor volume alone, to 50mm, when GNPs are spatially distributed also in the healthy tissues surrounding the tumor. Treatment simulations of five patients with breast cancer were performed with 6 and 15 MV photons assuming a partial breast irradiation. A closed analytical reformulation of the Local Effect Model coupled with the estimation of local dose deposited around a GNP was validated using an in vitro study for MDA‐MB‐231 tumoral cells. The expected treatment outcome was quantified in terms of tumor control probability (TCP) and normal tissue complication probability (NTCP) as a function of the spatially varying gold uptake. Results Breast cancer treatment planning simulations show improved treatment outcomes when GNPs are selectively concentrated in the tumor volume (i.e., σ = 0 mm). In particular, the TCP increases up to 18% for 5 × 10 5nanoparticles per cell in the tumor region depending on the treatment schedules, whereas an improvement of the therapeutic index is observed only for concentrations of about 10 5 GNPs per tumoral cell and limited spatial distribution in the normal tissue. Conclusions The model provides a useful framework to estimate the nanoparticle‐driven radiosensitivity in breast cancer treatment irradiation, accounting for the complex interplay between dose and GNP uptake distributions.